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Sample records for rayleigh scattering

  1. Rayleigh Scattering Diagnostics Workshop

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard (Compiler)

    1996-01-01

    The Rayleigh Scattering Diagnostics Workshop was held July 25-26, 1995 at the NASA Lewis Research Center in Cleveland, Ohio. The purpose of the workshop was to foster timely exchange of information and expertise acquired by researchers and users of laser based Rayleigh scattering diagnostics for aerospace flow facilities and other applications. This Conference Publication includes the 12 technical presentations and transcriptions of the two panel discussions. The first panel was made up of 'users' of optical diagnostics, mainly in aerospace test facilities, and its purpose was to assess areas of potential applications of Rayleigh scattering diagnostics. The second panel was made up of active researchers in Rayleigh scattering diagnostics, and its purpose was to discuss the direction of future work.

  2. Rayleigh's Scattering Revised

    NASA Astrophysics Data System (ADS)

    Kolomiets, Sergey; Gorelik, Andrey

    Mie’s waves while sounding within coincident volumes. Being sensitive to the size of scatters, Mie’s waves can give us additional information about particle size distribution. But how about using several wavelengths corresponding to Rayleigh’s diffraction on scatters only? Can any effects be detected in such a case and what performance characteristics of the equipment are required to detect them? The deceptive simplicity of the negative answer to the first part of the question posed will disappear if one collects different definitions of Rayleigh's scattering and consider them more closely than usually. Several definitions borrowed from the introductory texts and most popular textbooks and articles can be seen as one of the reasons for the research presented in the report. Hopefully, based on the comparison of them all, anyone could easily conclude that Rayleigh's scattering has been analyzed extensively, but despite this extensive analysis made fundamental ambiguities in introductory texts are not eliminated completely to date. Moreover, there may be found unreasonably many examples on how these ambiguities have already caused an error to be foreseen, published on the one article, amplified in another one, then cited with approval in the third one, before being finally corrected. Everything indicated that in the light of all the lesions learned and based on modern experimental data, it is time to address these issues again. After the discussion of ambiguities of Rayleigh's scattering concepts, the development of the corrections to original ideas looks relatively easy. In particular, there may be distinguished at least three characteristic regions of the revised models application from the point of view of the scattered field statistical averaging. The authors of the report suggest naming them Rayleigh’s region, Einstein’s region and the region with compensations of the scattering intensity. The most important fact is that the limits of applicability of all

  3. Interferometric Rayleigh Scattering Measurement System

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Danehy, Paul M. (Inventor); Lee, Joseph W. (Inventor)

    2008-01-01

    A method and apparatus for performing simultaneous multi-point measurements of multiple velocity components in a gas flow is described. Pulses of laser light are directed to a measurement region of unseeded gas to produce Rayleigh or Mie scattered light in a plurality of directions. The Rayleigh or Mie scattered light is collected from multiple directions and combined in a single collimated light beam. The Rayleigh or Mie scattered light is then mixed together with a reference laser light before it is passed through a single planar Fabry-Perot interferometer for spectral analysis. At the output of the interferometer, a high-sensitivity CCD camera images the interference fringe pattern. This pattern contains the spectral and spatial information from both the Rayleigh scattered light and the reference laser light. Interferogram processing software extracts and analyzes spectral profiles to determine the velocity components of the gas flow at multiple points in the measurement region. The Rayleigh light rejected by the interferometer is recirculated to increase the accuracy and the applicability of the method for measurements at high temperatures without requiring an increase in the laser energy.

  4. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    ERIC Educational Resources Information Center

    Liebl, Michael

    2010-01-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…

  5. Improvement in Rayleigh Scattering Measurement Accuracy

    NASA Technical Reports Server (NTRS)

    Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2012-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous velocity, density, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of an acousto-optic frequency shifting device to improve measurement accuracy in Rayleigh scattering experiments at the NASA Glenn Research Center. The frequency shifting device is used as a means of shifting the incident or reference laser frequency by 1100 MHz to avoid overlap of the Rayleigh and reference signal peaks in the interference pattern used to obtain the velocity, density, and temperature measurements, and also to calibrate the free spectral range of the Fabry-Perot etalon. The measurement accuracy improvement is evaluated by comparison of Rayleigh scattering measurements acquired with and without shifting of the reference signal frequency in a 10 mm diameter subsonic nozzle flow.

  6. Rayleigh scattering measurements of several fluorocarbon gases.

    PubMed

    Zadoo, Serena; Thompson, Jonathan E

    2011-11-01

    Integrating nephelometers are commonly used to monitor airborne particulate matter. However, they must be calibrated prior to use. The Rayleigh scattering coefficients (b(RS), Mm(-1)), scattering cross sections (σ(RS), cm(2)), and Rayleigh multipliers for tetrafluoromethane (R-14), sulfur hexafluoride, pentafluoroethane (HFC-125), hexafluoropropene (HFC-216), 1,1,1,2,3,3,3,-heptafluoropropane (HFC-227ea), and octafluorocyclobutane (C-318) are reported from measurements made using a Radiance Research M903 integrating nephelometer operating at λ = 530 nm and calibration with gases of known scattering constants. Rayleigh multipliers (±90% conf. int.) were found to be 2.6 ± 0.5, 6.60 ± 0.07, 7.5 ± 1, 14.8 ± 0.9, 15.6 ± 0.5, and 22.3 ± 0.8 times that of air, respectively. To the best of our knowledge, these are the first reported values for R-14, HFC-216, HFC-125, and C-318. Experimental accuracy is supported through measurements of values for SF(6) and HFC-227ea which agree to within 3% of previous literature reports. In addition to documenting fundamental Rayleigh scattering data for the first time, the information presented within will find use for calibration of optical scattering sensors such as integrating nephelometers. PMID:22027960

  7. Transient Rayleigh scattering from single semiconductor nanowires

    SciTech Connect

    Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M.; Yarrison-Rice, Jan M.; Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati

    2013-12-04

    Transient Rayleigh scattering spectroscopy is a new pump-probe technique to study the dynamics and cooling of photo-excited carriers in single semiconductor nanowires. By studying the evolution of the transient Rayleigh spectrum in time after excitation, one can measure the time evolution of the density and temperature of photo-excited electron-hole plasma (EHP) as they equilibrate with lattice. This provides detailed information of dynamics and cooling of carriers including linear and bimolecular recombination properties, carrier transport characteristics, and the energy-loss rate of hot electron-hole plasma through the emission of LO and acoustic phonons.

  8. Simultaneous CARS and Interferometric Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Grinstead, Keith D., Jr.; Tedder, Sarah; Cutler, Andrew D.

    2006-01-01

    This paper reports for the first time the combination of a dual-pump coherent anti-Stokes Raman scattering system with an interferometric Rayleigh scattering system (CARS - IRS) to provide time-resolved simultaneous measurement of multiple properties in combustion flows. The system uses spectrally narrow green (seeded Nd:YAG at 532 nm) and yellow (552.9 nm) pump beams and a spectrally-broad red (607 nm) beam as the Stokes beam. A spectrometer and a planar Fabry-Perot interferometer used in the imaging mode are used to record the spectrally broad CARS spectra and the spontaneous Rayleigh scattering spectra, respectively. Time-resolved simultaneous measurement of temperature, absolute mole fractions of N2, O2, and H2, and two components of velocity in a Hencken burner flame were performed to demonstrate the technique.

  9. Rayleigh scattering of linear alkylbenzene in large liquid scintillator detectors

    SciTech Connect

    Zhou, Xiang Zhang, Zhenyu; Liu, Qian; Zheng, Yangheng; Wurm, Michael; Zhang, Qingmin; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-07-15

    Rayleigh scattering poses an intrinsic limit for the transparency of organic liquid scintillators. This work focuses on the Rayleigh scattering length of linear alkylbenzene (LAB), which will be used as the solvent of the liquid scintillator in the central detector of the Jiangmen Underground Neutrino Observatory. We investigate the anisotropy of the Rayleigh scattering in LAB, showing that the resulting Rayleigh scattering length will be significantly shorter than reported before. Given the same overall light attenuation, this will result in a more efficient transmission of photons through the scintillator, increasing the amount of light collected by the photosensors and thereby the energy resolution of the detector.

  10. Optical switching by stimulated thermal Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Peterson, Lauren M.

    1986-06-01

    Preliminary experiments were conducted whose ultimate goal is to develop all-optical control functions useful in an all-optical or optical-electronic hybrid digital computer or for optical interconnects. Stimulated thermal Rayleigh scattering (STRS) based upon generator experiments was pursued for scattering angles of 90 deg and 180 deg (backscattering). A pulsed nitrogen laser pumped dye laser served as the radiation source and the interaction medium was a liquid to which an absorbing dye was added. STRS amplifier experiments were successful and gain was observed and studied parametrically using eosine dye in ethanol. The gain was found to increase (although the gain coefficient decreased) with increasing pump power and the gain was found to be a maximum at an absorption coefficient of about 2.6 per cm. The generator experiments did not lead to stimulated scattering due to the limited output power of the laser and its multi-longitudinal spectral mode content. These studies will be continued along with analytical modeling in order to characterize the interaction and to enable the optimization of the scattering process.

  11. Rayleigh Scattering for Measuring Flow in a Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Gomez, Carlos R.; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-engine-component test facility for surveying supersonic plumes from jet-engine exhaust. A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-enginecomponent test facility for surveying supersonic plumes from jet-engine exhaust

  12. Technical Report: Rayleigh Scattering Combustion Diagnostic

    SciTech Connect

    Adams, Wyatt; Hecht, Ethan

    2015-07-29

    A laser Rayleigh scattering (LRS) temperature diagnostic was developed over 8 weeks with the goal of studying oxy-combustion of pulverized coal char in high temperature reaction environments with high concentrations of carbon dioxide. Algorithms were developed to analyze data collected from the optical diagnostic system and convert the information to temperature measurements. When completed, the diagnostic will allow for the kinetic gasification rates of the oxy-combustion reaction to be obtained, which was previously not possible since the high concentrations of high temperature CO2 consumed thermocouples that were used to measure flame temperatures inside the flow reactor where the combustion and gasification reactions occur. These kinetic rates are important for studying oxycombustion processes suitable for application as sustainable energy solutions.

  13. Hyper-Rayleigh scattering in centrosymmetric systems

    NASA Astrophysics Data System (ADS)

    Williams, Mathew D.; Ford, Jack S.; Andrews, David L.

    2015-09-01

    Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E13, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E12M1 and E12E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E12E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties.

  14. Hyper-Rayleigh scattering in centrosymmetric systems

    SciTech Connect

    Williams, Mathew D.; Ford, Jack S.; Andrews, David L.

    2015-09-28

    Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E1{sup 3}, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E1{sup 2}M1 and E1{sup 2}E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E1{sup 2}E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties.

  15. Rayleigh scattering: blue sky thinking for future CMB observations

    SciTech Connect

    Lewis, Antony

    2013-08-01

    Rayleigh scattering from neutral hydrogen during and shortly after recombination causes the CMB anisotropies to be significantly frequency dependent at high frequencies. This may be detectable with Planck, and would be a strong signal in any future space-based CMB missions. The later peak of the Rayleigh visibility compared to Thomson scattering gives an increased large-scale CMB polarization signal that is a greater than 4% effect for observed frequencies ν ∼> 500GHz. There is a similar magnitude suppression on small scales from additional damping. Due to strong correlation between the Rayleigh and primary signal, measurement of the Rayleigh component is limited by noise and foregrounds, not cosmic variance of the primary CMB, and should observable over a wide range of angular scales at frequencies 200GHz ∼< ν ∼< 800GHz. I give new numerical calculations of the temperature and polarization power spectra, and show that future CMB missions could measure the temperature Rayleigh cross-spectrum at high precision, detect the polarization from Rayleigh scattering, and also accurately determine the cross-spectra between the Rayleigh temperature signal and primary polarization. The Rayleigh scattering signal may provide a powerful consistency check on recombination physics. In principle it can be used to measure additional horizon-scale primordial perturbation modes at recombination, and distinguish a significant tensor mode B-polarization signal from gravitational lensing at the power spectrum level.

  16. Mechanisms universally permitting hyper-Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Williams, Mathew D.; Ford, Jack S.; Andrews, David L.

    2015-02-01

    Hyper-Rayleigh scattering (HRS) is an incoherent variant of second harmonic generation. The theory involves terms of increasing order of optical nonlinearity: for molecules or unit cells that are centrosymmetric, and which accordingly lack even-order susceptibilities, HRS is often regarded as formally forbidden. However, for the three-photon interaction, theory based on the standard electric dipole approximation, represented as E13, does not include the detail required to describe what is observed experimentally, in the absence of a static field. New results emerge upon extending the theory to include E12E2 and E12M1, incorporating one electric quadrupolar or magnetic dipolar interaction respectively. Both additional interactions require the deployment of higher orders in the multipole expansion to govern these processes, with the E12E2 interaction analogous in rank and parity to a four-wave susceptibility. A key feature of the present work is its foundation upon a formal tensor derivation which does not oversimplify the molecular components, yet leads to results whose interpretation can be correlated with experimental observations. Results are summarized for the perpendicular detection of both parallel and perpendicular polarizations. Using such methods to investigate molecular systems that might have useful nonlinear characteristics, HRS therefore provides a route to data with direct physical interpretation, to enable more sophisticated design of molecules with sought optical properties.

  17. Rayleigh scattering in the atmospheres of hot stars

    NASA Astrophysics Data System (ADS)

    Fišák, J.; Krtička, J.; Munzar, D.; Kubát, J.

    2016-05-01

    Context. Rayleigh scattering is a result of an interaction of photons with bound electrons. Rayleigh scattering is mostly neglected in calculations of hot star model atmospheres because most of the hydrogen atoms are ionized and the heavier elements have a lower abundance than hydrogen. In atmospheres of some chemically peculiar stars, helium overabundant regions containing singly ionized helium are present and Rayleigh scattering can be a significant opacity source. Aims: We evaluate the contribution of Rayleigh scattering by neutral hydrogen and singly ionized helium in the atmospheres of hot stars with solar composition and in the atmospheres of helium overabundant stars. Methods: We computed several series of model atmospheres using the TLUSTY code and emergent fluxes using the SYNSPEC code. These models describe atmospheres of main sequence B-type stars with different helium abundance. We used an existing grid of models for atmospheres with solar chemical composition and we calculated an additional grid for helium-rich stars with N(He)/N(H) = 10. Results: Rayleigh scattering by neutral hydrogen can be neglected in atmospheres of hot stars, while Rayleigh scattering by singly ionized helium can be a non-negligible opacity source in some hot stars, especially in helium-rich stars.

  18. Correction of Rayleigh Scattering Effects in Cloud Optical Thickness Retrievals

    NASA Technical Reports Server (NTRS)

    Wang, Meng-Hua; King, Michael D.

    1997-01-01

    We present results that demonstrate the effects of Rayleigh scattering on the 9 retrieval of cloud optical thickness at a visible wavelength (0.66 Am). The sensor-measured radiance at a visible wavelength (0.66 Am) is usually used to infer remotely the cloud optical thickness from aircraft or satellite instruments. For example, we find that without removing Rayleigh scattering effects, errors in the retrieved cloud optical thickness for a thin water cloud layer (T = 2.0) range from 15 to 60%, depending on solar zenith angle and viewing geometry. For an optically thick cloud (T = 10), on the other hand, errors can range from 10 to 60% for large solar zenith angles (0-60 deg) because of enhanced Rayleigh scattering. It is therefore particularly important to correct for Rayleigh scattering contributions to the reflected signal from a cloud layer both (1) for the case of thin clouds and (2) for large solar zenith angles and all clouds. On the basis of the single scattering approximation, we propose an iterative method for effectively removing Rayleigh scattering contributions from the measured radiance signal in cloud optical thickness retrievals. The proposed correction algorithm works very well and can easily be incorporated into any cloud retrieval algorithm. The Rayleigh correction method is applicable to cloud at any pressure, providing that the cloud top pressure is known to within +/- 100 bPa. With the Rayleigh correction the errors in retrieved cloud optical thickness are usually reduced to within 3%. In cases of both thin cloud layers and thick ,clouds with large solar zenith angles, the errors are usually reduced by a factor of about 2 to over 10. The Rayleigh correction algorithm has been tested with simulations for realistic cloud optical and microphysical properties with different solar and viewing geometries. We apply the Rayleigh correction algorithm to the cloud optical thickness retrievals from experimental data obtained during the Atlantic

  19. Progress on a Rayleigh Scattering Mass Flux Measurement Technique

    NASA Technical Reports Server (NTRS)

    Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.; Hirt, Stefanie M.

    2010-01-01

    A Rayleigh scattering diagnostic has been developed to provide mass flux measurements in wind tunnel flows. Spectroscopic molecular Rayleigh scattering is an established flow diagnostic tool that has the ability to provide simultaneous density and velocity measurements in gaseous flows. Rayleigh scattered light from a focused 10 Watt continuous-wave laser beam is collected and fiber-optically transmitted to a solid Fabry-Perot etalon for spectral analysis. The circular interference pattern that contains the spectral information that is needed to determine the flow properties is imaged onto a CCD detector. Baseline measurements of density and velocity in the test section of the 15 cm x 15 cm Supersonic Wind Tunnel at NASA Glenn Research Center are presented as well as velocity measurements within a supersonic combustion ramjet engine isolator model installed in the tunnel test section.

  20. Rayleigh Scattering Diagnostic for Dynamic Measurement of Velocity and Temperature

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, J.

    2001-01-01

    A new technique for measuring dynamic gas velocity and temperature is described. The technique is based on molecular Rayleigh scattering of laser light, so no seeding of the flow is necessary. The Rayleigh scattered light is filtered with a fixed cavity, planar mirror Fabry-Perot interferometer. A minimum number of photodetectors were used in order to allow the high data acquisition rate needed for dynamic measurements. One photomultiplier tube (PMT) was used to measure the total Rayleigh scattering, which is proportional to the gas density. Two additional PMTs were used to detect light that passes through two apertures in a mask located in the interferometer fringe plane. An uncertainty analysis was used to select the optimum aperture parameters and to predict the measurement uncertainty due to photon shot-noise. Results of an experiment to measure the velocity of a subsonic free jet are presented.

  1. Multiple-Point Mass Flux Measurement System Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Clem, Michelle M.

    2009-01-01

    A multiple-point Rayleigh scattering diagnostic is being developed to provide mass flux measurements in gas flows. Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, temperature, and velocity measurements. Rayleigh scattered light from a focused 18 Watt continuous-wave laser beam is directly imaged through a solid Fabry-Perot etalon onto a CCD detector which permits spectral analysis of the light. The spatial resolution of the measurements is governed by the locations of interference fringes, which can be changed by altering the etalon characteristics. A prototype system has been used to acquire data in a Mach 0.56 flow to demonstrate feasibility of using this system to provide mass flux measurements. Estimates of measurement uncertainty and recommendations for system improvements are presented

  2. Rayleigh scattering in few-mode optical fibers

    PubMed Central

    Wang, Zhen; Wu, Hao; Hu, Xiaolong; Zhao, Ningbo; Mo, Qi; Li, Guifang

    2016-01-01

    The extremely low loss of silica fibers has enabled the telecommunication revolution, but single-mode fiber-optic communication systems have been driven to their capacity limits. As a means to overcome this capacity crunch, space-division multiplexing (SDM) using few-mode fibers (FMF) has been proposed and demonstrated. In single-mode optical fibers, Rayleigh scattering serves as the dominant mechanism for optical loss. However, to date, the role of Rayleigh scattering in FMFs remains elusive. Here we establish and experimentally validate a general model for Rayleigh scattering in FMFs. Rayleigh backscattering not only sets the intrinsic loss limit for FMFs but also provides the theoretical foundation for few-mode optical time-domain reflectometry, which can be used to probe perturbation-induced mode-coupling dynamics in FMFs. We also show that forward inter-modal Rayleigh scattering ultimately sets a fundamental limit on inter-modal-crosstalk for FMFs. Therefore, this work not only has implications specifically for SDM systems but also broadly for few-mode fiber optics and its applications in amplifiers, lasers, and sensors in which inter-modal crosstalk imposes a fundamental performance limitation. PMID:27775003

  3. Control of experimental uncertainties in filtered Rayleigh scattering measurements

    NASA Technical Reports Server (NTRS)

    Forkey, Joseph N.; Finkelstein, N. D.; Lempert, Walter R.; Miles, Richard B.

    1995-01-01

    Filtered Rayleigh Scattering is a technique which allows for measurement of velocity, temperature, and pressure in unseeded flows, spatially resolved in 2-dimensions. We present an overview of the major components of a Filtered Rayleigh Scattering system. In particular, we develop and discuss a detailed theoretical model along with associated model parameters and related uncertainties. Based on this model, we then present experimental results for ambient room air and for a Mach 2 free jet, including spatially resolved measurements of velocity, temperature, and pressure.

  4. Rayleigh scattering from argon clusters in a planar expansion

    SciTech Connect

    DeArmond, F. M.; Suelzer, J.; Masters, M. F.

    2008-05-01

    Rayleigh scattering is presented as evidence for the presence of large argon clusters formed in a planar expansion. Based on the observed scattering signal, the dependence of mean cluster size on stagnation pressure is {proportional_to}P{sub 0}{sup 3.38}. This is in contrast to the dependence of the mean cluster size on stagnation pressure for a symmetric expansion of {proportional_to}P{sub 0}{sup 2.29}.

  5. Rayleigh scattering on the cavitation region emerging in liquids.

    PubMed

    Shneider, M N; Pekker, M

    2016-03-15

    It is shown that the scattering of laser radiation off cavitation ruptures in fluids is similar to scattering by gas particles. When the characteristic dimensions of microscopic voids and bubbles are considerably smaller than the laser wavelength, the scattered light is in the Rayleigh regime, which allows for the detection of early stage cavitation. Simple estimates of the scattered radiation intensity and the dynamics of its changes in connection with the generation of cavitation in the test volume are obtained, allowing us to find the critical conditions for cavitation inception. PMID:26977641

  6. Rayleigh scattering of a spherical sound wave.

    PubMed

    Godin, Oleg A

    2013-02-01

    Acoustic Green's functions for a homogeneous medium with an embedded spherical obstacle arise in analyses of scattering by objects on or near an interface, radiation by finite sources, sound attenuation in and scattering from clouds of suspended particles, etc. An exact solution of the problem of diffraction of a monochromatic spherical sound wave on a sphere is given by an infinite series involving products of Bessel functions and Legendre polynomials. In this paper, a simple, closed-form solution is obtained for scattering by a sphere with a radius that is small compared to the wavelength. Soft, hard, impedance, and fluid obstacles are considered. The solution is valid for arbitrary positions of the source and receiver relative to the scatterer. Low-frequency scattering is shown to be rather sensitive to boundary conditions on the surface of the obstacle. Low-frequency asymptotics of the scattered acoustic field are extended to transient incident waves. The asymptotic expansions admit an intuitive interpretation in terms of image sources and reduce to classical results in appropriate limiting cases.

  7. Rayleigh-Brillouin Scattering in Binary-Gas Mixtures.

    PubMed

    Gu, Z; Ubachs, W; Marques, W; van de Water, W

    2015-06-19

    Precise measurements are performed on spectral line shapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral line shape without adjustable parameters, yielding excellent agreement for the case of binary monatomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media. PMID:26196978

  8. Dual-Line Detection Rayleigh Scattering Measurements of Density and Temperature

    NASA Technical Reports Server (NTRS)

    Annen, Kurt; Otugen, Volkan; Seasholtz, Richard

    1996-01-01

    Measurements of the laser Rayleigh scattering signal in a flow to determine density and temperature have been commonly employed in open flames and in wind tunnel environments. In these measurements, the density or reciprocal temperature is correlated with the Rayleigh scattering signal intensity. A major advantage of Rayleigh scattering for these applications is the simple experimental arrangement allowed by this technique. Intensity-based Rayleigh scattering measurements of density and temperature have been limited to relatively clean flows in open environments so that interference from particle scattering and laser scattering is minimal. A new approach, using dual-line detection Rayleigh (DLDR) scattering extends the applicability of Rayleigh scattering measurements of density and temperature to enclosed environments where surface scattering interference is high. Depending on particle size and optical properties, this approach may also reduce interference from particle scattering.

  9. Rayleigh scattering and nonlinear inversion of elastic waves

    SciTech Connect

    Gritto, R.

    1995-12-01

    Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.

  10. Time-Resolved Rayleigh Scattering Measurements in Hot Gas Flows

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen

    2008-01-01

    A molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded gas flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultipler tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. Mean and rms velocity and temperature fluctuation measurements in both an electrically-heated jet facility with a 10-mm diameter nozzle and also in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA Glenn Research Center are presented.

  11. Linear approximation of Rayleigh-Brillouin scattering spectra.

    PubMed

    Binietoglou, Ioannis; Giampouras, Paris; Belegante, Livio

    2016-09-20

    Rayleigh-Brillouin scattering is the basis of many remote sensing techniques, including high spectral resolution lidar measurements of aerosols and wind. Rayleigh-Brillouin spectra can be accurately estimated using physics-based models like the so-called Tenti's S6 and Pan's S7 models. Unfortunately, these are computationally expensive and can be the bottleneck for real-time lidar processing and iterative parameter estimation problems. This short article describes a very efficient linear approximation of the Rayleigh-Brillouin spectra based on Principal Component Analysis (PCA). Using PCA, the outputs of the above models can be approximated with very high accuracy using a single matrix multiplication. The described method can be applied to the output of any detailed scattering model, thus it can be used for a wide range of problems, e.g., for scattering from different gases (Air, N2, O2,…) and for different ranges of temperature and pressure. The precision of the approximation can be adapted to the requirements of the studied problem, and can easily exceed the actual accuracy of the reference models. PMID:27661601

  12. Laser scattering on an atmospheric pressure plasma jet: disentangling Rayleigh, Raman and Thomson scattering

    NASA Astrophysics Data System (ADS)

    van Gessel, A. F. H.; Carbone, E. A. D.; Bruggeman, P. J.; van der Mullen, J. J. A. M.

    2012-02-01

    Laser scattering provides a very direct method for measuring the local densities and temperatures inside a plasma. We present new experimental results of laser scattering on an argon atmospheric pressure microwave plasma jet operating in an air environment. The plasma is very small so a high spatial resolution is required to study the effect of the penetration of air molecules into the plasma. The scattering signal has three overlapping contributions: Rayleigh scattering from heavy particles, Thomson scattering from free electrons and Raman scattering from molecules. The Rayleigh scattering signal is filtered out optically with a triple grating spectrometer. The disentanglement of the Thomson and Raman signals is done with a newly designed fitting method. With a single measurement we determine profiles of the electron temperature, electron density, gas temperature, partial air pressure and the N2/O2 ratio, with a spatial resolution of 50 µm, and including absolute calibration.

  13. An equipment for Rayleigh scattering of Mössbauer radiation

    NASA Astrophysics Data System (ADS)

    Enescu, S. E.; Bibicu, I.; Zoran, V.; Kluger, A.; Stoica, A. D.; Tripadus, V.

    1998-07-01

    A personal computer driven equipment designed for Rayleigh scattering of Mössbauer radiation experiments at room temperature is described. The performances of the system were tested using like scatterers crystals with different mosaic divergences: lithium fluoride (LiF) and pyrolytic graphite (C). The equipment, suitable for any kind of Mössbauer scattering experiments, permits low and adjustable horizontal divergences of the incident beam. On décrit un équipement dédié aux mesures de diffusion Rayleigh de la radiation Mössbauer controlée par ordinateur. Les performances du système ont été testées sur des cristaux ayant des divergences de mosaïque différentes: le fluorure de lithium (LiF) et le graphite pyrolytique (C). L'équipement, qui peut être utilisé dans des différents types d'expérimentations basées sur la diffusion de la radiation Mössbauer, admet des divergences horizontales du faisceau incident faibles et réglables.

  14. Analytical evaluation of atomic form factors: Application to Rayleigh scattering

    SciTech Connect

    Safari, L.; Santos, J. P.; Amaro, P.; Jänkälä, K.; Fratini, F.

    2015-05-15

    Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wave functions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.

  15. POLARIZED LIGHT REFLECTED AND TRANSMITTED BY THICK RAYLEIGH SCATTERING ATMOSPHERES

    SciTech Connect

    Natraj, Vijay; Hovenier, J. W.

    2012-03-20

    Accurate values for the intensity and polarization of light reflected and transmitted by optically thick Rayleigh scattering atmospheres with a Lambert surface underneath are presented. A recently reported new method for solving integral equations describing Chandrasekhar's X- and Y-functions is used. The results have been validated using various tests and techniques, including the doubling-adding method, and are accurate to within one unit in the eighth decimal place. Tables are stored electronically and expected to be useful as benchmark results for the (exo)planetary science and astrophysics communities. Asymptotic expressions to obtain Stokes parameters for a thick layer from those of a semi-infinite atmosphere are also provided.

  16. Multiple Point Dynamic Gas Density Measurements Using Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard; Panda, Jayanta

    1999-01-01

    A nonintrusive technique for measuring dynamic gas density properties is described. Molecular Rayleigh scattering is used to measure the time-history of gas density simultaneously at eight spatial locations at a 50 kHz sampling rate. The data are analyzed using the Welch method of modified periodograms to reduce measurement uncertainty. Cross-correlations, power spectral density functions, cross-spectral density functions, and coherence functions may be obtained from the data. The technique is demonstrated using low speed co-flowing jets with a heated inner jet.

  17. Thomson Scattering Density Calibration by Rayleigh and Rotational Raman Scattering on NSTX

    SciTech Connect

    B.P. LeBlanc

    2008-07-16

    The multi-point Thomson scattering (MPTS) diagnostic measures the profiles of the electron temperature Te(R) and density ne(R) on the horizontal midplane of NSTX. Normal operation makes use of Rayleigh scattering in nitrogen or argon to derive the density profile. While the Rayleigh scattering ne(R) calibration has been validated by comparison with other density measurements and through its correlation with plasma phenomena, it does require dedicated detectors at the laser wavelength in this filter polychromator based diagnostic. The presence of dust and/or stray laser light precludes routine use of these dedicated spectral channels for Thomson scattering measurement. Hence it is of interest to investigate the use of Raman scattering in nitrogen for the purpose of density calibration, since it could free up detection equipment, which could then be used for the instrumentation of additional radial channels. In this paper the viewing optics "geometrical factor" profiles obtained from Rayleigh and Raman scattering are compared. While both techniques agree nominally, residual effects on the order of 10% remain and will be discussed.

  18. Optical measurement of acoustic pressure amplitudes-at the sensitivity limits of Rayleigh scattering.

    PubMed

    Rausch, Anne; Fischer, André; Kings, Nancy; Bake, Friedrich; Roehle, Ingo

    2012-07-01

    Rayleigh scattering is a measurement technique applicable for the determination of density distributions in various technical or natural flows. The current sensitivity limits of the Rayleigh scattering technique were investigated experimentally. It is shown that it is possible to measure density oscillations caused by acoustic pressure oscillations noninvasively and directly. Acoustical standing waves in a rectangular duct were investigated using Rayleigh scattering and compared to microphone measurements. The comparison showed a sensitivity of the Rayleigh scattering technique of 75 Pa (7·10(-4) kg/m(3)) and a precision of 14 Pa (1·10(-4) kg/m(3)). Therefore, it was also shown that Rayleigh scattering is applicable for acoustic measurements. PMID:22743495

  19. Characterization of a Combined CARS and Interferometric Rayleigh Scattering System

    NASA Technical Reports Server (NTRS)

    Tedder, Sarah A.; Bivolaru, Daniel; Danehy, Paul M.; Weikl, M. C.; Beyrau, F.; Seeger, T.; Cutler, Andrew D.

    2007-01-01

    This paper describes the characterization of a combined Coherent anti-Stokes Raman Spectroscopy and Interferometric Rayleigh Scattering (CARS-IRS) system by reporting the accuracy and precision of the measurements of temperature, species mole fraction of N2, O2, and H2, and two-components of velocity. A near-adiabatic H2-air Hencken burner flame was used to provide known properties for measurements made with the system. The measurement system is also demonstrated in a small-scale Mach 1.6 H2-air combustion-heated supersonic jet with a co-flow of H2. The system is found to have a precision that is sufficient to resolve fluctuations of flow properties in the mixing layer of the jet.

  20. Coherent Rayleigh-Brillouin scattering as a flow diagnostic technique

    SciTech Connect

    Graul, J. S.; Lilly, T. C.

    2014-12-09

    Broadband coherent Rayleigh-Brillouin scattering (CRBS) was used to measure translational gas temperatures for nitrogen at the ambient pressure of 0.8 atm using a purpose-built Fabry-Perot etalon spectrometer. Temperatures derived from the CRBS spectral analysis were compared with experimentally-measured temperatures, and were found to be, on average, within 2% of the experimentally-measured value. Axial flow velocities from a double jet at a pressure ratio of 0.38 were also measured by looking at the Doppler shift of the CRBS line shape. With recent developments in chirped laser technology and the capacity of CRBS to simultaneously provide thermodynamic and bulk flow information, the CRBS line shape acquisition and analysis technique presented here may allow for future time-resolved, characterization of aerospace flows.

  1. Rayleigh Scattering Measurements Using a Tunable Liquid Crystal Fabry-Perot Interferometer

    NASA Technical Reports Server (NTRS)

    Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.

    2010-01-01

    Spectroscopic Rayleigh scattering is an established flow diagnostic that has the ability to provide simultaneous density, velocity, and temperature measurements. The Fabry-Perot interferometer or etalon is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating these flow properties. This paper investigates the use of a tunable liquid crystal (LC) Fabry-Perot etalon in Rayleigh scattering experiments at NASA Glenn Research Center. The LC etalon provides a robust interferometry system that can be tuned rapidly by adjusting the voltage applied to the liquid crystal interface. Tuning the interferometer is often necessary to control the physical locations of the concentric interference fringes when Rayleigh light is imaged through the LC etalon. The LC etalon diagnostic system was tested in a 1-cm diameter nozzle flow in two different scattering configurations to evaluate its usefulness for Rayleigh measurements compared to a traditional non-tunable fused silica Fabry-Perot etalon.

  2. Ring effect studies: Rayleigh scattering, including molecular parameters for rotational Raman scattering, and the Fraunhofer spectrum.

    PubMed

    Chance, K V; Spurr, R J

    1997-07-20

    Improved parameters for the description of Rayleigh scattering in air and for the detailed rotational Raman scattering component for scattering by O(2) and N(2) are presented for the wavelength range 200-1000 nm. These parameters enable more accurate calculations to be made of bulk molecular scattering and of the Ring effect for a variety of atmospheric radiative transfer and constituent retrieval applications. A solar reference spectrum with accurate absolute vacuum wavelength calibration, suitable for convolution with the rotational Raman spectrum for Ring effect calculations, has been produced at 0.01-nm resolution from several sources. It is convolved with the rotational Raman spectra of O(2) and N(2) to produce an atmospheric Ring effect source spectrum.

  3. Matrix operator theory of radiative transfer. 1: rayleigh scattering.

    PubMed

    Plass, G N; Kattawar, G W; Catchings, F E

    1973-02-01

    An entirely rigorous method for the solution of the equations for radiative transfer based on the matrix operator theory is reviewed. The advantages of the present method are: (1) all orders of the reflection and transmission matrices are calculated at once; (2) layers of any thickness may be combined, so that a realistic model of the atmosphere can be developed from any arbitrary number of layers, each with different properties and thicknesses; (3) calculations can readily be made for large optical depths and with highly anisotropic phase functions; (4) results are obtained for any desired value of the surface albedo including the value unity and for a large number of polar and azimuthal angles including the polar angle theta = 0 degrees ; (5) all fundamental equations can be interpreted immediately in terms of the physical interactions appropriate to the problem; (6) both upward and downward radiance can be calculated at interior points from relatively simple expressions. Both the general theory and its history together with the method of calculation are discussed. As a first example of the method numerous curves are given for both the reflected and transmitted radiance for Rayleigh scattering from a homogeneous layer for a range of optical thicknesses from 0.0019 to 4096, surface albedo A = 0, 0.2, and 1, and cosine of solar zenith angle micro = 1, 0.5397, and 0.1882. It is shown that the matrix operator approach contains the doubling method as a special case.

  4. Cavity-modified collective Rayleigh scattering of two atoms.

    PubMed

    Reimann, René; Alt, Wolfgang; Kampschulte, Tobias; Macha, Tobias; Ratschbacher, Lothar; Thau, Natalie; Yoon, Seokchan; Meschede, Dieter

    2015-01-16

    We report on the observation of cooperative radiation of exactly two neutral atoms strongly coupled to the single mode field of an optical cavity, which is close to the lossless-cavity limit. Monitoring the cavity output power, we observe constructive and destructive interference of collective Rayleigh scattering for certain relative distances between the two atoms. Because of cavity backaction onto the atoms, the cavity output power for the constructive two-atom case (N=2) is almost equal to the single-emitter case (N=1), which is in contrast to free-space where one would expect an N^{2} scaling of the power. These effects are quantitatively explained by a classical model as well as by a quantum mechanical model based on Dicke states. We extract information on the relative phases of the light fields at the atom positions and employ advanced cooling to reduce the jump rate between the constructive and destructive atom configurations. Thereby we improve the control over the system to a level where the implementation of two-atom entanglement schemes involving optical cavities becomes realistic. PMID:25635545

  5. Imaging of Passive Scalar Fields by Filtered Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Kearney, Sean; Grasser, Thomas; Beresh, Steven; Schefer, Robert

    2002-11-01

    Filtered Rayleigh Scattering (FRS) is a molecular-filter-based, laser-diagnostic approach for multiparameter flowfield imaging that has been gaining popularity over the past 5-10 years [1]. Advantages of FRS for noninvasive gas-phase imaging include: (1) elimination of particle or chemical seeding requirements, (2) increased optical noise rejection allowing imaging close to walls and in "dirty" laboratory environments, (3) imaging of multiple flowfield parameters with a single diagnostic. In this work, the construction and performance of a FRS optical system for passive scalar imaging at Sandia National Laboratories is presented. Data were obtained in an open lab where no special precautions for the elimination of room particulate were made. Results from nonreacting jets and from a premixed flame are shown. Temperature imaging in a nonreacting, steady calibration jet reveals the precision of the time-averaged FRS thermometry results to be ±20 K, or 4of the characteristic temperature difference, while the single-laser-pulse precision is degraded to approximately ±40-50 K. These results are adequate for combustion thermometry purposes. Relative to the jet temperature measurements, species concentration imaging of a buoyant helium jet displays increased signal dynamic range and further improved precision. Reacting flow measurements from the combustion-product region of a methane-air Hencken-type premixed flame are also presented and a comparison of FRS and coherent anti-Stokes Raman scattering (CARS) experiments to calculated adiabatic-equilibrium product temperatures is made which validates the suitability of our FRS instrument for combustion temperature imaging. [1]G.S. Elliott, N. Glumac, and C.D. Carter, Meas. Sci. Tech., 12, 452, 2001.

  6. Ultraviolet Molecular Rayleigh Scattering Used to Measure Velocity in High-Speed Flow

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1997-01-01

    Molecular Rayleigh scattering offers a means to measure gas flow parameters including density, temperature, and velocity. No seeding of the flow is necessary. The Rayleigh scattered power is proportional to the gas density, the spectral width is related to the gas temperature, and the shift in the frequency of the spectral peak is proportional to one component of the fluid velocity. Velocity measurements based on Rayleigh scattering are more suitable for high-speed flow, where the bulk fluid velocity is on the order of, or larger than, the molecular thermal velocities. Use of ultraviolet wavelengths for Rayleigh scattering diagnostics is attractive for two reasons. First, the Rayleigh scattering cross section is proportional to the inverse 4th power of the wavelength. And second, the reflectivity of metallic surfaces is generally less than it is at longer wavelengths. This is of particular interest in confined flow situations, such as in small wind tunnels and aircraft engine components, where the stray laser light scattered from the windows and internal surfaces in the test facility limits the application of Rayleigh scattering diagnostics. In this work at the NASA Lewis Research Center, molecular Rayleigh scattering of the 266-nm fourth harmonic of a pulsed, injection seeded Nd:YAG (neodymium:yttriumaluminum- garnet) laser was used to measure velocity in a supersonic free air jet with a 9.3- mm exit diameter. The frequency of the Rayleigh scattered light was analyzed with a planar mirror Fabry-Perot interferometer used in a static imaging mode, with the images recorded on a cooled, high-quantum-efficiency charge-coupled discharge (CCD) camera. In addition, some unshifted light from the same laser pulse was imaged through the interferometer to generate a reference. Data were obtained with single laser pulses at velocities up to Mach 1.3. The measured velocities were in good agreement with velocities calculated from isentropic flow relations. Our conclusion from

  7. High-speed laser anemometry based on spectrally resolved Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1991-01-01

    Laser anemometry in unseeded flows based on the measurement of the spectrum of Rayleigh scattered laser light is reviewed. The use of molecular scattering avoids the well known problems (particle lag, biasing effects, seed generation, seed injection) of seeded flows. The fundamental limits on velocity measurement accuracy are determined using maximum likelihood methods. Measurement of the Rayleigh spectrum with scanning Fabry-Perot interferometers is analyzed and accuracy limits are established for both single pass and multipass configurations. Multipass configurations have much higher selectivity and are needed for measurements where there is a large amount of excess noise caused by stray laser light. It is shown that Rayleigh scattering is particularly useful for supersonic and hypersonic flows. The results of the analysis are compared with measurements obtained with a Rayleigh scattering diagnostic developed for study of the exhaust plume of a small hydrogen-oxygen rocket, where the velocities are in the range of 1000 to 5000 m/sec.

  8. Investigation of Condensation/Clustering Effects on Rayleigh Scattering Measurements in a Hypersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Tyler, Charles

    1996-01-01

    Rayleigh scattering, a nonintrusive measurement technique for the measurement of density in a hypersonic wind tunnel, is under investigation at Wright Laboratory's Mach 6 wind tunnel. Several adverse effects, i.e., extraneous scatter off walls and windows, hinder Rayleigh scattering measurements. Condensation and clustering of flow constituents also present formidable obstacles. Overcoming some of these difficulties, measurements have been achieved while the Mach 6 test section was pumped down to a vacuum, as well as for actual tunnel operation for various stagnation pressures at fixed stagnation temperatures. Stagnation pressures ranged from 0.69 MPa to 6.9 MPa at fixed stagnation temperatures of 511, 556, and 611 K. Rayleigh scatter results show signal levels much higher than expected for molecular scattering in the wind tunnel. Even with higher than expected signals, scattering measurements have been made in the flowfield of an 8-degree half-angle blunt nose cone with a nose radius of 1.5 cm.

  9. Contribution of Rayleigh scattering on Brillouin comb line generation in Raman fiber laser.

    PubMed

    Zamzuri, Abdul Kadir; Al-Mansoori, Mohammed Hayder; Samsuri, Norhakimah Md; Mahdi, Mohd Adzir

    2010-06-20

    We demonstrate the generation of multiple Brillouin Stokes lines generation assisted by Rayleigh scattering in Raman fiber laser. The linear cavity is utilized to take advantage of the Rayleigh scattering effect, and it also produces two strong spectral peaks at 1555 and 1565nm. Under a strong pumping condition, the Rayleigh backscatters contribute to the oscillation efficiency, which increases the Brillouin Stokes lines intensity between these two wavelength ranges. The multiple Stokes lines get stronger by suppressing the buildup of free-running longitudinal modes in the laser structure.

  10. Investigation of differential diffusion in turbulent jet flows using planar laser Rayleigh scattering

    SciTech Connect

    Dibble, Robert W.; Long, Marshall B.

    2005-12-01

    A series of laser Rayleigh-scattering experiments has been performed to investigate the effects of differential molecular diffusion in turbulent nonreacting jet flows. A turbulent jet of a mixture of Freon and H{sub 2} exiting into coflowing air was studied at various Reynolds numbers. In laminar flow, Rayleigh scattering clearly showed H{sub 2} diffusing ahead of Freon. In turbulent flow, the instantaneous Rayleigh images showed differential diffusion at the many interfaces between jet fluid and entrained air. Yet, ensemble averages of instantaneous images showed no average diffusion of H{sub 2} ahead of Freon.

  11. Use of two profilers during MCTEX for unambiguous identification of Bragg scattering and Rayleigh scattering

    SciTech Connect

    Gage, K.S.; Williams, C.R.; Ecklund, W.L.; Johnston, P.E.

    1999-11-01

    A 2835-MHz (10.6-cm wavelength) profiler and a 920-MHz (32.6-cm wavelength) profiler were collocated by the NOAA Aeronomy Laboratory at Garden Point, Australia, in the Tiwi Islands during the Maritime Continent Thunderstorm Experiment (MCTEX) field campaign in November and December 1995. The two profilers were directed vertically and observed vertical velocities in the clear atmosphere and hydrometeor fall velocities in deep precipitating cloud systems. In the absence of Rayleigh scatterers, the profilers obtain backscattering from the refractive index irregularities created from atmospheric turbulence acting upon refractive index gradients. This kind of scattering is commonly referred to as Bragg scattering and is only weakly dependent on the radar wavelength provided the radar half-wavelength lies within the inertial subrange of homogeneous, isotropic turbulence. In the presence of hydrometeors the profilers observe Rayleigh backscattering from hydrometeors much as weather radars do and this backscatter is very dependent upon radar wavelength, strongly favoring the shorter wavelength profiler resulting in a 20-dB enhancement of the ability of the 2835-MHz profiler to observe hydrometeors. This paper presents observations of equivalent reflectivity, Doppler velocity, and spectral width made by collocated profilers during MCTEX. Differential reflectivity is used to diagnose the type of echo observed by the profilers in the spectral moment data.

  12. Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.

    1999-01-01

    The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.

  13. Gas temperature measurements using the dual-line detection Rayleigh scattering technique

    NASA Technical Reports Server (NTRS)

    Otugen, M. Volkan; Seasholtz, Richard G.; Annen, Kurt D.

    1992-01-01

    A new laser-induced Rayleigh scattering method is presented for the improved temperature diagnostics of gas flows. In the present technique, the two lines of a copper vapor laser are used to obtain the time and space resolved temperature. A single set of optics is used to form the optical probe and to collect the signal simultaneously from both the 510 nm and the 578 nm lines. The dual-line detection allows for the determination and removal of surface-scattered laser light from a Rayleigh signal thereby improving the applicability of Rayleigh scattering to near wall flows with a high degree of glare. An optical system using the dual-line detection technique is built, calibrated and tested in a hot air jet under various levels of background contamination. The results indicate that highly accurate temperature measurements are possible even when the laser-line background intensity, captured by the collecting optics, is five times that of the Rayleigh signal.

  14. Stimulated Rayleigh-Bragg scattering in two-photon absorbing media

    SciTech Connect

    He, Guang S.; Lu Changgui; Zheng Qingdong; Prasad, Paras N.; Zerom, Petros; Boyd, Robert W.; Samoc, Marek

    2005-06-15

    The origin and mechanism of backward stimulated Rayleigh scattering in two-photon absorbing media are studied theoretically and experimentally. This type of stimulated scattering has the unusual features of no frequency shift and low pump threshold requirement compared to all other known stimulated scattering effects. This frequency-unshifted stimulated Rayleigh scattering effect can be well explained by a two-photon-excitation-enhanced Bragg grating reflection model. The reflection of the forward pump beam from this stationary Bragg grating may substantially enhance the backward Rayleigh scattering beam, providing a positive feedback mechanism without causing any frequency shift. A two-counterpropagating-beam-formed grating experiment in a two-photon absorbing dye solution is conducted. The measured dynamic behavior of Bragg grating formation and reflectivity properties are basically consistent with the predictions from the proposed model.

  15. Study of Injection of Helium into Supersonic Air Flow Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seaholtz, Richard G.; Buggele, Alvin E.

    1997-01-01

    A study of the transverse injection of helium into a Mach 3 crossflow is presented. Filtered Rayleigh scattering is used to measure penetration and helium mole fraction in the mixing region. The method is based on planar molecular Rayleigh scattering using an injection-seeded, frequency-doubled ND:YAG pulsed laser and a cooled CCD camera. The scattered light is filtered with an iodine absorption cell to suppress stray laser light. Preliminary data are presented for helium mole fraction and penetration. Flow visualization images obtained with a shadowgraph and wall static pressure data in the vicinity of the injection are also presented.

  16. Demonstration and Analysis of Filtered Rayleigh Scattering Flow Field Diagnostic System

    NASA Technical Reports Server (NTRS)

    Forkey, Joseph N.; Lempert, Walter R.; Miles, Richard B.

    1996-01-01

    Filtered Rayleigh Scattering (FRS) is a diagnostic technique which measures velocity, temperature, and pressure by determining Doppler shift, total intensity, and spectral line shape of laser induced Rayleigh-Brillouin scattering. In the work reported here, this is accomplished by using a narrow line width, injection seeded Nd-YAG laser sheet to induce Rayleigh-Brillouin scattering from a gas flow. This light is passed through an optical notch filter, and transmitted light is imaged onto an intensified charge coupled display (CCD) camera. By monitoring the grayscale value at a particular pixel while the laser frequency is tuned, the convolution between the Rayleigh-Brillouin scattering profile and the filter transmission profile is attained. Since the filter profile can be independently measured, it can be deconvolved from the measuring signal, yielding the Rayleigh-Brillouin scattering profile. From this profile, flow velocity, temperature, and pressure are determined. In this paper the construction and characterization of the optical notch filter and a newly developed frequency apparatus are discussed.

  17. Radial profile of micro-discharge temperature measured by ultraviolet laser Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Adams, Steven; Caplinger, James

    2012-10-01

    Air micro-discharge temperature profiles have been derived from measurements of elastic Rayleigh scatter of an ultraviolet laser pulse. Rayleigh scatter images have been recorded to measure spatially resolved translational temperatures along the radial dimension of the dc micro-discharge at various currents. The scatter image intensity along the laser beam axis is proportional to the background gas target density and thus, according to the ideal gas law, is inversely proportional to gas translational temperature. By measuring the scatter image with and without a discharge, the temperature was determined in one-dimension along the laser beam passing radially through the discharge. This laser scatter technique was compared to the technique of measuring rotational and vibrational temperatures by passive optical emission spectroscopy (OES) of the N2 second positive system. Results were generally consistent with the common assumption that Tvibrational>>Trotational=Ttranslational. Slight differences between Trotational and Ttranslational measured by laser scatter and OES techniques respectively are discussed.

  18. In situ nanoparticle diagnostics by multi-wavelength Rayleigh-Mie scattering ellipsometry

    NASA Astrophysics Data System (ADS)

    Gebauer, G.; Winter, J.

    2003-04-01

    We present and discuss the method of multiple-wavelength Rayleigh-Mie scattering ellipsometry for the in situ analysis of nanoparticles. It is applied to the problem of nanoparticles suspended in low-pressure plasmas. We discuss experimental results demonstrating that the size distribution and the complex refractive index can be determined with high accuracy and present a study on the in situ analysis of etching of melamine-formaldehyde nanoparticles suspended in an oxygen plasma. It is also shown that particles with a shell structure (core plus mantle) can be analysed by Rayleigh-Mie scattering ellipsometry. Rayleigh-Mie scattering ellipsometry is also applicable to in situ analysis of nanoparticles under high gas pressures and in liquids.

  19. Planar Rayleigh Scattering Results in Helium/Air Mixing Experiments in a Mach 6 Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Balla, R. Jeffrey; Hillard, M. E.; Anders, J. B.; Exton, R. J.; Waitz, I. A.

    1991-01-01

    Planar Rayleigh scattering measurements using an ArF-excimer laser have been performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach 6facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross sectional area (5 cm by 10 cm) of the flow field in the absence of clusters.

  20. Flow Visualization of Density in a Cryogenic Wind Tunnel Using Planar Rayleigh and Raman Scattering

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Shirinzadeh, Behrooz

    2002-01-01

    Using a pulsed Nd:YAG laser (532 nm) and a gated, intensified charge-coupled device, planar Rayleigh and Raman scattering techniques have been used to visualize the unseeded Mach 0.2 flow density in a 0.3-meter transonic cryogenic wind tunnel. Detection limits are determined for density measurements by using both unseeded Rayleigh and Raman (N2 vibrational) methods. Seeding with CO2 improved the Rayleigh flow visualization at temperatures below 150 K. The seeded Rayleigh version was used to demonstrate the observation of transient flow features in a separated boundary layer region, which was excited with an oscillatory jet. Finally, a significant degradation of the laser light sheet, in this cryogenic facility, is discussed.

  1. Determination of the quantized topological magneto-electric effect in topological insulators from Rayleigh scattering

    PubMed Central

    Ge, Lixin; Zhan, Tianrong; Han, Dezhuan; Liu, Xiaohan; Zi, Jian

    2015-01-01

    Topological insulators (TIs) exhibit many exotic properties. In particular, a topological magneto-electric (TME) effect, quantized in units of the fine structure constant, exists in TIs. Here, we theoretically study the scattering properties of electromagnetic waves by TI circular cylinders particularly in the Rayleigh scattering limit. Compared with ordinary dielectric cylinders, the scattering by TI cylinders shows many unusual features due to the TME effect. Two proposals are suggested to determine the TME effect of TIs simply by measuring the electric-field components of scattered waves in the far field at one or two scattering angles. Our results could also offer a way to measure the fine structure constant. PMID:25609462

  2. Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

    2008-01-01

    This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

  3. Horizontal lidar measurements for the proof of spontaneous Rayleigh-Brillouin scattering in the atmosphere.

    PubMed

    Witschas, Benjamin; Lemmerz, Christian; Reitebuch, Oliver

    2012-09-01

    Several atmospheric lidar techniques rely on the exact knowledge of the spectral line shape of molecular scattered light in air, which, however, has not been accurately measured in real atmosphere up to now. In this paper we report on the investigation of spontaneous Rayleigh-Brillouin scattering within the atmosphere, utilizing horizontal lidar measurements (λ=355 nm, θ=180°) performed from the mountain observatory Schneefernerhaus (2650 m), located below Germany's highest mountain, the Zugspitze. These lidar measurements give proof of the effect of Brillouin scattering within the atmosphere for the first time to our knowledge. The measurements confirm that the Tenti S6 model can be used to adequately describe spontaneous Rayleigh-Brillouin spectra of light scattered in air under real atmospheric conditions. The presented results are of relevance for spectrally resolving lidars like those deployed on the Atmospheric Dynamics Mission Aeolus (ADM-Aeolus) andthe Earth Clouds, Aerosols, and Radiation Explorer Mission (EarthCARE).

  4. Study of Fabry-Perot Etalon Stability and Tuning for Spectroscopic Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Clem, Michelle M.; Mielke-Fagan, Amy F.; Elam, Kristie A.

    2010-01-01

    The Fabry-Perot interferometer is a commonly employed instrument for resolving the spectrum of molecular Rayleigh scattered light for the purpose of evaluating flow properties such as gas velocity and temperature. Rayleigh scattered light from a focused laser beam can be directly imaged through a solid Fabry-Perot etalon onto a CCD detector to provide the spectral content of the scattered light. The spatial resolution of the measurements is governed by the locations of interference fringes. The location of the fringes can be changed by altering the etalon?s physical characteristics, such as thickness and index of refraction. For a fused silica solid etalon the physical properties can be adjusted by changing the etalon temperature; hence changing the order of the interference pattern and the physical fringe locations. Controlling the temperature of the etalon can provide for a slow time-response spatial scanning method for this type of etalon system. A custom designed liquid crystal Fabry-Perot (LCFP) can provide for a fast time-response method of scanning the etalon system. Voltage applied to the liquid crystal interface sets the etalon?s properties allowing Rayleigh measurements to be acquired at varying spatial locations across the image of the laser beam over a very short time period. A standard fused silica etalon and a tunable LCFP etalon are characterized to select the system that is best suited for Rayleigh scattering measurements in subsonic and supersonic flow regimes. A frequency-stabilized laser is used to investigate the apparent frequency stability and temperature sensitivity of the etalon systems. Frequency stability and temperature sensitivity data of the fused silica and LCFP etalon systems are presented in this paper, along with measurements of the LCFP etalon?s tuning capabilities. Rayleigh scattering velocity measurements with both etalon systems are presented, in an effort to determine which etalon is better suited to provide optical flow

  5. On the critical role of Rayleigh scattering in single-molecule surface-enhanced Raman scattering via a plasmonic nanogap.

    PubMed

    Chen, Bao-Qin; Zhang, Chao; Li, Jiafang; Li, Zhi-Yuan; Xia, Younan

    2016-08-25

    Electromagnetic and chemical enhancement mechanisms are commonly used to account for single-molecule surface-enhanced Raman scattering (SM-SERS). Due to many practical limitations, however, the overall enhancement factor summed up from these two mechanisms is typically 5-6 orders of magnitude below the level of 10(14)-10(15) required for SM-SERS. Here, we demonstrate that the multiple elastic Rayleigh scattering of a molecule could play a critical role in further enhancing the Raman signal, when the molecule is trapped in a 2 nm gap between two Ag nanoparticles, pushing the overall enhancement factor close to the level needed for SM-SERS. As a universal physical process for all molecules interacting with light, we believe that Rayleigh scattering plays a pivotal and as yet unrecognized role in SERS, in particular, for enabling single-molecule sensitivity. PMID:27526632

  6. Ultraviolet Rayleigh scatter imaging in atmospheric microdischarges for spatial temperature profiles

    NASA Astrophysics Data System (ADS)

    Caplinger, James; Adams, Steven; Hensley, Amber; Tolson, Boyd

    2014-10-01

    Spatially resolved temperature measurements within a microdischarge in atmospheric pressure air have been conducted using Rayleigh scattering of a pulsed ultraviolet laser. The scatter image intensity along the laser beam axis is proportional to the background gas target density and thus, according to the ideal gas law, is inversely proportional to gas translational temperature. By measuring the scatter image with and without a discharge, the temperature was determined in 1-dimension along the laser beam passing radially through the discharge. The 1-dimensional scattering intensity profiles were then used to generate 2-dimensional cross-sectional slices of temperature by transitioning the height of the laser beam. The cross-sectional temperature profiles exhibited a high degree of cylindrical symmetry with the radial width of the high temperature region expanding with increasing discharge current. Peak temperatures determined by Rayleigh scattering for each current were compared to temperatures derived from standard optical emission spectral analyses of N2(C-B) bands, where the calculated rotational temperatures from emission were in reasonable agreement with the Rayleigh translational temperature profiles. Air Force Office of Scientific Research.

  7. Translational Temperature Profiles in Atmospheric Air Microdischarges by Ultraviolet Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Adams, Steven; Caplinger, James; Hensley, Amber; Tolson, Allen

    2014-03-01

    Spatially resolved temperature measurements within a microdischarge in atmospheric pressure air have been conducted using Rayleigh scattering of a pulsed ultraviolet laser. The scatter image intensity along the laser beam axis is proportional to the background gas target density and thus, according to the ideal gas law, is inversely proportional to gas translational temperature. By measuring the scatter image with and without a discharge, the temperature was determined in 1-dimension along the laser beam passing radially through the discharge. The 1-dimensional scattering intensity profiles were then used to generate 2-dimensional cross-sectional slices of temperature by transitioning the height of the laser beam. The cross-sectional temperature profiles exhibited a high degree of cylindrical symmetry with the radial width of the high temperature region expanding with increasing discharge current. Peak temperatures determined by Rayleigh scattering for each current were compared to temperatures derived from standard optical emission spectral analyses of N2(C-B) bands, where the calculated rotational temperatures from emission were in reasonable agreement with the Rayleigh translational temperature profiles.

  8. Errors induced by the neglect of polarization in radiance calculations for Rayleigh-scattering atmospheres

    NASA Technical Reports Server (NTRS)

    Mishchenko, M. I.; Lacis, A. A.; Travis, L. D.

    1994-01-01

    Although neglecting polarization and replacing the rigorous vector radiative transfer equation by its approximate scalar counterpart has no physical background, it is a widely used simplification when the incident light is unpolarized and only the intensity of the reflected light is to be computed. We employ accurate vector and scalar multiple-scattering calculations to perform a systematic study of the errors induced by the neglect of polarization in radiance calculations for a homogeneous, plane-parallel Rayleigh-scattering atmosphere (with and without depolarization) above a Lambertian surface. Specifically, we calculate percent errors in the reflected intensity for various directions of light incidence and reflection, optical thicknesses of the atmosphere, single-scattering albedos, depolarization factors, and surface albedos. The numerical data displayed can be used to decide whether or not the scalar approximation may be employed depending on the parameters of the problem. We show that the errors decrease with increasing depolarization factor and/or increasing surface albedo. For conservative or nearly conservative scattering and small surface albedos, the errors are maximum at optical thicknesses of about 1. The calculated errors may be too large for some practical applications, and, therefore, rigorous vector calculations should be employed whenever possible. However, if approximate scalar calculations are used, we recommend to avoid geometries involving phase angles equal or close to 0 deg and 90 deg, where the errors are especially significant. We propose a theoretical explanation of the large vector/scalar differences in the case of Rayleigh scattering. According to this explanation, the differences are caused by the particular structure of the Rayleigh scattering matrix and come from lower-order (except first-order) light scattering paths involving right scattering angles and right-angle rotations of the scattering plane.

  9. Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering.

    PubMed

    Antoun, Ayman; Pavlov, Michael Y.; Tenson, Tanel; Ehrenberg M, M åNs

    2004-01-01

    Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix. PMID:15103398

  10. RAYLEIGH SCATTERING IN THE ATMOSPHERE OF THE WARM EXO-NEPTUNE GJ 3470B

    SciTech Connect

    Dragomir, Diana; Benneke, Björn; Pearson, Kyle A.; Crossfield, Ian J. M.; Barman, Travis; Eastman, Jason; Biddle, Lauren I.

    2015-12-01

    GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes.

  11. Rayleigh Scattering Diagnostic for Simultaneous Measurements of Dynamic Density and Velocity

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, J.

    2000-01-01

    A flow diagnostic technique based on the molecular Rayleigh scattering of laser light is used to obtain dynamic density and velocity data in turbulent flows. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer and recording information about the interference pattern with a multiple anode photomultiplier tube (PMT). An artificial neural network is used to process the signals from the PMT to recover the velocity time history, which is then used to calculate the velocity power spectrum. The technique is illustrated using simulated data. The results of an experiment to measure the velocity power spectrum in a low speed (100 rn/sec) flow are also presented.

  12. Rayleigh Scattering Diagnostic for Measurement of Velocity and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2002-01-01

    A new molecular Rayleigh scattering based flow diagnostic is used for the first time to measure the power spectrum of gas density and radial velocity component in the plumes of high speed jets. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer used in the static, imaging mode. The PC based data acquisition system is capable of simultaneous sampling of velocity and density at rates to 100 kHz and data record lengths to 10 million. Velocity and density power spectra and velocity-density cross spectra are presented for a subsonic jet, an underexpanded screeching jet, and for Mach 1.4 and Mach 1.8 supersonic jets. Software and hardware interfaces were developed to allow computer control of all aspects of the experiment and data acquisition.

  13. Rayleigh Scattering Diagnostic for Dynamic Measurement of Velocity Fluctuations in High Speed Jets

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2001-01-01

    A flow diagnostic technique based on the molecular Rayleigh scattering of laser light is used to obtain dynamic density and velocity data in a high speed flow. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer used in the static, imaging mode. An analysis is presented that established a lower bound for measurement uncertainty of about 20 m/sec for individual velocity measurements obtained in a 100 microsecond time interval. Software and hardware interfaces were developed to allow computer control of all aspects of the experiment and data acquisition. The signals from three photomultiplier tubes were simultaneously recorded using photon counting at a 10 kHz sampling rate and 10 second recording periods. Density and velocity data, including distribution functions and power spectra, taken in a Mach 0.8 free jet, are presented.

  14. Dynamics of macroscopic fluctuations in aqueous systems according to Rayleigh scattering data

    NASA Astrophysics Data System (ADS)

    Belovolova, L. V.; Glushkov, M. V.; Timashev, S. F.

    2015-09-01

    The general question of the existence of macrofluctuations of physical characteristics of aqueous systems are discussed. Using the example of analyzing fluctuations in the Rayleigh scattering of natural untreated water, along with catholyte and anolyte obtained in its electrochemical treatment, the possibility of obtaining of quantitative information on the states and dynamics of changes in such systems is shown. Data on the parameters of oscillations in the Rayleigh light scattering of water catholyte and anolyte immediately after electrolysis, and one and two days after its completion, are presented. Calculations are performed using the general phenomenological approach to analyzing chaotic signals (flicker-noise spectroscopy). Quantitative characteristics that reveal substantial differences in the dynamics of macrofluctuations that develop in the catholyte and anolyte of the studied water are presented.

  15. Reduction of double Rayleigh scattering noise in distributed Raman amplifiers employing higher-order pumping.

    PubMed

    Bolognini, Gabriele; Bononi, Alberto

    2009-04-27

    We present a theoretical study of the performance of distributed Raman amplifiers with higher order pumping schemes, focusing in particular on double Rayleigh scattering (DRS) noise. Results show an unexpected significant DRS noise reduction for pumping order higher than third, allowing for an overall performance improvement of carefully designed distributed amplifiers, ensuring a large optical signal-to-noise ratio improvement together with reduced DRS-induced penalties.

  16. Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

    DOE PAGESBeta

    Gerakis, A.; Shneider, M. N.; Stratton, B. C.

    2016-07-21

    Here, we measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co2, SF6, and air, and confirm the already established quadratic dependence of the signal on the gas density. Finally, we propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition.

  17. Development of Filtered Rayleigh Scattering for Accurate Measurement of Gas Velocity

    NASA Technical Reports Server (NTRS)

    Miles, Richard B.; Lempert, Walter R.

    1995-01-01

    The overall goals of this research were to develop new diagnostic tools capable of capturing unsteady and/or time-evolving, high-speed flow phenomena. The program centers around the development of Filtered Rayleigh Scattering (FRS) for velocity, temperature, and density measurement, and the construction of narrow linewidth laser sources which will be capable of producing an order MHz repetition rate 'burst' of high power pulses.

  18. Intracavity Rayleigh/Mie Scattering for Multipoint, Two-Component Velocity Measurement

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.

    2006-01-01

    A simultaneous multi-point two-component Doppler velocimeter is described. The system uses two optical cavities: a Fabry-Perot etalon and an optical cavity for collecting and re-circulating the Rayleigh/Mie scattered light that is collected from the measurement volume in two parallel, but opposite directions. Single-pulse measurements of two orthogonal components of the velocity vector in a supersonic free jet were performed to demonstrate the technique. The re-circulation of the light rejected by the interferometer input mirror also increased the signal intensity by a factor of 3.5. 2005 Optical Society of America Interferometric Rayleigh scattering has previously been used for single-point velocity measurements in unseeded gas flow. However, this past work has generally been limited to probing with continuous-wave lasers resulting in time-averaged measurements of velocity. Multiple velocity components have been measured simultaneously by separate instruments.1,2 It has also been demonstrated that two orthogonal velocity components can be measured simultaneously at one point using one interferometer by reflecting back the probing laser beam, although this approach results in directional ambiguity of the flow velocity vector.3 This measurement ambiguity was removed by prior knowledge of the approximate magnitude and sign of the velocity components. Furthermore, it was shown that multiple points could be measured simultaneously with a Rayleigh scattering interferometric approach, but only one component of velocity was measured.4 Another method of performing multiple component velocity measurements with Rayleigh scattering uses a pair of cameras to image the flow, one of which views the flow through an iodine gas filter. This iodine-filter technique has the advantage of allowing high-resolution velocity imaging, but it generally has a lower dynamic range.

  19. Apparatus and Method for Measuring Strain in Optical Fibers using Rayleigh Scatter

    NASA Technical Reports Server (NTRS)

    Froggatt, Mark E. (Inventor); Moore, Jason P. (Inventor)

    2003-01-01

    An apparatus and method for measuring strain in an optical fiber using the spectral shift of Rayleigh scattered light. The interference pattern produced by an air gap reflector and backscattered radiation is measured. Using Fourier Transforms, the spectrum of any section of fiber can be extracted. Cross correlation with an unstrained measurement produces a correlation peak. The location of the correlation peak indicates the strain level in the selected portion of optical fiber.

  20. Development of a noninvasive diabetes screening device using the ratio of fluorescence to Rayleigh scattered light

    NASA Astrophysics Data System (ADS)

    Yu, Nai-Teng; Krantz, Brian S.; Eppstein, Jonathan A.; Ignotz, Keith D.; Samuels, Mark A.; Long, James R.; Price, John

    1996-07-01

    We have developed a new lens measurement system that simultaneously measures the intensities of fluorescence and Rayleigh components at various distances into the lens along the optical axis. The noninvasive measurement is performed through an undilated pupil, and with the assistance of a pupil tracking system that facilitates maintaining the x and y positions of the sample volume to within +/- 100 micrometers of any programmed 'lock' position. The intensity of the Rayleigh component that is used to normalize the measured fluorescent signal serves to correct the attenuation effects due to absorption and lens light scatter. This report, resulting from a SpectRx Site L clinical study using a refined instrumentation, presents analysis of fluorescence and Rayleigh data from the lenses of 923 controls and 239 diabetic subjects ranging from 23 to 75 years old. Fluorescence and Rayleigh data have been obtained via confocal mode from various locations nominally along the lens optical axis for controls and diabetics, at different ages, using three pairs of excitation and collection wavelengths: 364/495 nm, 434/495 nm, and 485/515 nm. For control subjects, there exists a strong, almost linear relationship between age and fluorescence, while diabetic subjects tend to deviate from this age-fluorescence relationship. Our data show that the lenses of diabetic patients are subject to an accelerated aging process, presumably due to an elevated level of brown and fluorescence protein adducts and crosslinks from nonenzymatic glycosylation. We have also shown that by using the measured Rayleigh profiles to normalize the measured fluorescence, most of the absorption effects are removed and therefore the separation between the fluorescence of diabetics and controls is greatly improved. Thus, the device for measuring fluorescence/Rayleigh ratios can be used to noninvasively screen populations for possible undiagnosed diabetes.

  1. Rapid determination of ciprofloxacin lactate in drugs by the Rayleigh light scattering technique

    NASA Astrophysics Data System (ADS)

    Xiao, Jian Bo; Yang, Chun Sheng; Lian Ren, Fen; Jiang, Xin Yu; Xu, Ming

    2007-03-01

    A Rayleigh light scattering technique to determine ciprofloxacin lactate (CPFL) in drugs by tetraphenylboron sodium (TPB) was developed. Ciprofloxacin lactate was found to bind B(C6H5)4- anion and transformed to CPFL-TPB aggregate which displayed intense Rayleigh scattering light. Effects of factors such as wavelength, acidity, stabilizers and interferents on the RLS of CPFL-TPB were investigated in detail. The RLS intensity of the CPFL-TPB suspension was obtained in acetate buffer (0.50 mol L-1, pH = 4.0). The Rayleigh scattering light intensity at the maximum RLS peak of 408 nm was linear to the concentration of ciprofloxacin lactate in the range of 8.0-20.0 µg mL-1 with a detection limit of 6.0 µg mL-1. Good results were also obtained with the recovery range of 93.68-104.06%. The method was applied to determine ciprofloxacin lactate in injections, eye drops and tablets, showing high sensitivity and accuracy compared with the high performance liquid chromatography method (HPLC) according to Chinese Pharmacopoeia.

  2. Velocity and Temperature Measurement in Supersonic Free Jets Using Spectrally Resolved Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Panda, J.; Seasholtz, R. G.

    2004-01-01

    The flow fields of unheated, supersonic free jets from convergent and convergent-divergent nozzles operating at M = 0.99, 1.4, and 1.6 were measured using spectrally resolved Rayleigh scattering technique. The axial component of velocity and temperature data as well as density data obtained from a previous experiment are presented in a systematic way with the goal of producing a database useful for validating computational fluid dynamics codes. The Rayleigh scattering process from air molecules provides a fundamental means of measuring flow properties in a non-intrusive, particle free manner. In the spectrally resolved application, laser light scattered by the air molecules is collected and analyzed using a Fabry-Perot interferometer (FPI). The difference between the incident laser frequency and the peak of the Rayleigh spectrum provides a measure of gas velocity. The temperature is measured from the spectral broadening caused by the random thermal motion and density is measured from the total light intensity. The present point measurement technique uses a CW laser, a scanning FPI and photon counting electronics. The 1 mm long probe volume is moved from point to point to survey the flow fields. Additional arrangements were made to remove particles from the main as well as the entrained flow and to isolate FPI from the high sound and vibration levels produced by the supersonic jets. In general, velocity is measured within +/- 10 m/s accuracy and temperature within +/- 10 K accuracy.

  3. Rayleigh scattering correlation spectroscopy on diffusion dynamics of nanoparticles under intense laser irradiation

    NASA Astrophysics Data System (ADS)

    Hee, Ping-Yu; Uwada, Takayuki; Okano, Kazunori; Miura, Atsushi; Masuhara, Hiroshi

    2013-09-01

    Rayleigh scattering correlation microspectroscopy is developed and applied to study diffusion dynamics of some nanospheres in water. It was clearly found that the diffusion constant of gold nanoparticles decreased with increasing excitation laser power at the excitation wavelength of higher absorption cross section. This behavior was explained in terms of a coupling between laser trapping by the scattering excitation laser itself and laser heating of the particle. In the case of non-absorbing nanospheres such as silica and polystyrene, the excitation power dependence can be ascribed only to the laser trapping. Experimental setup is introduced, theoretical formulation is described, and future development of this measurement is considered.

  4. Rayleigh approximation for the scattering of small partially charged sand particles.

    PubMed

    Li, Xingcai; Min, Xing; Liu, Dandan

    2014-07-01

    Based on the Rayleigh approximation, this paper presents the electromagnetic scattering properties of the small partially charged isotropic sphere and those of a similar anisotropic sphere and then discusses the effect of surface charges on particles' optical properties. The numerical simulation results show that the surface charges on a charged particle can enhance the scattering of the incident waves, and the effect on an anisotropic charged sphere is much greater than that on an isotropic charged particle. Therefore it is necessary to consider the medium property (isotropic or anisotropic) and electric effects of dust particles in the remote sensing of sandstorms. PMID:25121437

  5. Spatially-and Temporally-Resolved Multi-Parameter Interferometric Rayleigh Scattering System and Method

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel (Inventor); Cutler, Andrew D. (Inventor); Danehy, Paul M. (Inventor)

    2015-01-01

    A system that simultaneously measures the translational temperature, bulk velocity, and density in gases by collecting, referencing, and analyzing nanosecond time-scale Rayleigh scattered light from molecules is described. A narrow-band pulsed laser source is used to probe two largely separated measurement locations, one of which is used for reference. The elastically scattered photons containing information from both measurement locations are collected at the same time and analyzed spectrally using a planar Fabry-Perot interferometer. A practical means of referencing the measurement of velocity using the laser frequency, and the density and temperature using the information from the reference measurement location maintained at constant properties is provided.

  6. Standoff detection of large organic molecules using Rydberg fingerprint spectroscopy and microwave Rayleigh scattering

    SciTech Connect

    Rudakov, Fedor M; Zhang, Zhili

    2012-01-01

    We present a technique for nonintrusive and standoff detection of large organic molecules using coherent microwave Rayleigh scattering from plasma produced by structure sensitive photoionization through Rydberg states. We test the method on 1,4-diazobicyclooctane. Transitions between the 3s Rydberg state and higher lying Rydberg states are probed using two-color photoionization with 266?nm photons and photons in the range of 460-2400 nm. Photoionization is detected using microwave radiation, which is scattered by the unbounded electrons. Highly resolved Rydberg spectra are acquired in vacuum and in air.

  7. Dynamic Measurement of Temperature, Velocity, and Density in Hot Jets Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2009-01-01

    A molecular Rayleigh scattering technique is utilized to measure gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz, providing fluctuation information up to 5 kHz based on the Nyquist theorem. A high-power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultiplier tubes operated in the photon counting mode allow high-frequency sampling of the total signal level and the circular interference pattern to provide dynamic density, temperature, and velocity measurements. Mean and root mean square velocity, temperature, and density, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA John H. Glenn Research Center at Lewis Field. The Rayleigh measurements are compared with particle image velocimetry data and computational fluid dynamics predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

  8. Dynamic Measurement of Temperature, Velocity, and Density in Hot Jets Using Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2008-01-01

    A molecular Rayleigh scattering technique was utilized to measure time-resolved gas temperature, velocity, and density in unseeded gas flows at sampling rates up to 10 kHz. A high power continuous-wave (cw) laser beam was focused at a point in an air flow field and Rayleigh scattered light was collected and fiber-optically transmitted to a Fabry-Perot interferometer for spectral analysis. Photomultipler tubes operated in the photon counting mode allowed high frequency sampling of the total signal level and the circular interference pattern to provide time-resolved density, temperature, and velocity measurements. Mean and rms velocity and temperature, as well as power spectral density calculations, are presented for measurements in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at the NASA Glenn Research Center (GRC). The Rayleigh measurements are compared with particle image velocimetry data and CFD predictions. This technique is aimed at aeronautics research related to identifying noise sources in free jets, as well as applications in supersonic and hypersonic flows where measurement of flow properties, including mass flux, is required in the presence of shocks and ionization occurrence.

  9. Long-range measurement of Rayleigh scatter signature beyond laser coherence length based on coherent optical frequency domain reflectometry.

    PubMed

    Ohno, Shingo; Iida, Daisuke; Toge, Kunihiro; Manabe, Tetsuya

    2016-08-22

    Long-range C-OFDR measurement of fiber Rayleigh scatter signature is described. The Rayleigh scatter signature, which is an interference pattern of backscatters from the random refractive indices in fibers, is known to be applicable to fiber identification and temperature or strain sensing by measuring its repeatability and its spectral shift. However, these applications have not been realized at ranges beyond the laser coherence length since laser phase noise degrades its repeatability. This paper proposes and demonstrates a method for analyzing the optical power spectrum of local Rayleigh backscatter to overcome the limitation imposed by laser phase noise. The measurable range and spatial performance are also investigated experimentally with respect to the remaining phase noise and noise reduction by signal averaging with the proposed method. The feasibility of Rayleigh scatter signature measurement for long-range applications is confirmed. PMID:27557243

  10. Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

    NASA Astrophysics Data System (ADS)

    Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc

    2016-05-01

    A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.

  11. Single-pulse Multi-point Multi-component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Lee, Joseph W.; Gaffney, Richard L., Jr.; Cutler, Andrew W.

    2006-01-01

    A simultaneous multi-point, multi-component velocimeter using interferometric detection of the Doppler shift of Rayleigh, Mie, and Rayleigh-Brillouin scattered light in supersonic flow is described. The system uses up to three sets of collection optics and one beam combiner for the reference laser light to form a single collimated beam. The planar Fabry-Perot interferometer used in the imaging mode for frequency detection preserves the spatial distribution of the signal reasonably well. Single-pulse multi-points measurements of up to two orthogonal and one non-orthogonal components of velocity in a Mach 2 free jet were performed to demonstrate the technique. The average velocity measurements show a close agreement with the CFD calculations using the VULCAN code.

  12. Temperature Deviations in the Midlatitude Mesosphere During Stratospheric Warmings as Measured with Rayleigh-Scatter Lidar

    NASA Astrophysics Data System (ADS)

    Sox, Leda; Wickwar, Vincent; Fish, Chad; Herron, Joshua P.

    2016-06-01

    While mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected an extensive set of temperature data for 11 years in the 45-90 km altitude range. This work focuses on the extensive Rayleigh lidar observations made during six major SSW events that occurred between 1993 and 2004, providing a climatological study of the midlatitude mesospheric temperatures during these SSW events. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions during SSW events, and warmings in the lower mesosphere.

  13. Estimation of effective atomic number in the Rayleigh to Compton scattering ratio using different methods

    NASA Astrophysics Data System (ADS)

    Kurudirek, M.; Büyükyıldız, M.

    2016-06-01

    The Rayleigh to Compton scattering ratio (R/C) is a very convenient parameter, which can be utilized in material analysis and estimating effective atomic number (Zeff). In the case for a relatively low scattering angle, for which the energy of the Compton scattered photons is not very much different from that of incident photons, the corrections due to self-absorption for Rayleigh and Compton scattering will be roughly equal. Therefore, it enables a result to be obtained which is almost independent of X-ray attenuation inside the sample and it will depend only on the material under investigation. The most frequently used method for calculation of Zeff available in literature is plotting R/C of elements as a function of atomic number and constituting the best fit curve. From this fit curve, the respective Zeff can be determined using R/C of the material. In the present study, we report Zeff of different materials using different methods such as interpolation and direct methods as possible alternatives to the most common fitting method. The results were compared with the experiments wherever possible. The agreement between interpolation method and the fitting method was found to be very satisfactory as relative changes (%) were always less than 9% while the direct method results with somehow significantly higher values of Zeff when compared to the other methods.

  14. Setting up a Rayleigh Scattering Based Flow Measuring System in a Large Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Panda, Jayanta; Gomez, Carlos R.

    2002-01-01

    A molecular Rayleigh scattering based air density measurement system has been built in a large nozzle testing facility at NASA Glenn Research Center. The technique depends on the light scattering by gas molecules present in air; no artificial seeding is required. Light from a single mode, continuous wave laser was transmitted to the nozzle facility by optical fiber, and light scattered by gas molecules, at various points along the laser beam, is collected and measured by photon-counting electronics. By placing the laser beam and collection optics on synchronized traversing units, the point measurement technique is made effective for surveying density variation over a cross-section of the nozzle plume. Various difficulties associated with dust particles, stray light, high noise level and vibration are discussed. Finally, a limited amount of data from an underexpanded jet are presented and compared with expected variations to validate the technique.

  15. Temperature-dependent bulk viscosity of nitrogen gas determined from spontaneous Rayleigh-Brillouin scattering.

    PubMed

    Gu, Ziyu; Ubachs, Wim

    2013-04-01

    Values for the bulk viscosity η(b) of molecular nitrogen gas (N2) were derived from spontaneous Rayleigh-Brillouin scattering at ultraviolet wavelengths (λ=366.8 nm) and at a 90° scattering angle. Analysis of the scattering profiles yields values showing a linear increasing trend, ranging from η(b)=0.7×10(-5) to 2.0×10(-5) kg·m(-1)·s(-1) in the temperature interval from 255 to 340 K. The present values, pertaining to hypersound acoustics at frequencies in the gigahertz domain, are found to be in agreement with results from acoustic attenuation experiments in N2 performed at megahertz frequencies.

  16. Rayleigh scatter in kilovoltage x-ray imaging: is the independent atom approximation good enough?

    PubMed

    Poludniowski, G; Evans, P M; Webb, S

    2009-11-21

    Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks in medical kilovoltage x-ray imaging. As a means of comparison, we incorporate a more realistic 'interference function' model into a custom-written Monte Carlo code. First, we conduct simulations of scatter from isolated voxels of soft tissue, adipose, cortical bone and spongiosa. Then, we simulate scatter profiles from a cylinder of water and from phantoms of a patient's head, thorax and pelvis, constructed from diagnostic-quality CT data sets. Lastly, we reconstruct CT numbers from simulated sets of projection images and investigate the quantitative effects of the approximation. We show that the IAA can produce errors of several per cent of the total scatter, across a projection image, for typical x-ray beams and patients. The errors in reconstructed CT number, however, for the phantoms simulated, were small (typically < 10 HU). The IAA can therefore be considered sufficient for the modelling of scatter correction in CT imaging. Where accurate quantitative estimates of scatter in individual projection images are required, however, the appropriate interference functions should be included.

  17. Rayleigh scatter in kilovoltage x-ray imaging: is the independent atom approximation good enough?

    NASA Astrophysics Data System (ADS)

    Poludniowski, G.; Evans, P. M.; Webb, S.

    2009-11-01

    Monte Carlo simulation is the gold standard method for modelling scattering processes in medical x-ray imaging. General-purpose Monte Carlo codes, however, typically use the independent atom approximation (IAA). This is known to be inaccurate for Rayleigh scattering, for many materials, in the forward direction. This work addresses whether the IAA is sufficient for the typical modelling tasks in medical kilovoltage x-ray imaging. As a means of comparison, we incorporate a more realistic 'interference function' model into a custom-written Monte Carlo code. First, we conduct simulations of scatter from isolated voxels of soft tissue, adipose, cortical bone and spongiosa. Then, we simulate scatter profiles from a cylinder of water and from phantoms of a patient's head, thorax and pelvis, constructed from diagnostic-quality CT data sets. Lastly, we reconstruct CT numbers from simulated sets of projection images and investigate the quantitative effects of the approximation. We show that the IAA can produce errors of several per cent of the total scatter, across a projection image, for typical x-ray beams and patients. The errors in reconstructed CT number, however, for the phantoms simulated, were small (typically < 10 HU). The IAA can therefore be considered sufficient for the modelling of scatter correction in CT imaging. Where accurate quantitative estimates of scatter in individual projection images are required, however, the appropriate interference functions should be included.

  18. A systematic study of Rayleigh-Brillouin scattering in air, N2, and O2 gases

    NASA Astrophysics Data System (ADS)

    Gu, Ziyu; Ubachs, Wim

    2014-09-01

    Spontaneous Rayleigh-Brillouin scattering experiments in air, N2, and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90° scattering angle. Measurements of the Rayleigh-Brillouin spectral scattering profile were conducted at high signal-to-noise ratio for all three species, yielding high-quality spectra unambiguously showing the small differences between scattering in air, and its constituents N2 and O2. Comparison of the experimental spectra with calculations using the Tenti S6 model, developed in the 1970s based on linearized kinetic equations for molecular gases, demonstrates that this model is valid to high accuracy for N2 and O2, as well as for air. After previous measurements performed at 366 nm, the Tenti S6 model is here verified for a second wavelength of 403 nm, and for the pressure-temperature parameter space covered in the present study (250-340 K and 0.6-3 bars). In the application of the Tenti S6 model, based on the transport coefficients of the gases, such as thermal conductivity κ, internal specific heat capacity cint and shear viscosity η, as well as their temperature dependencies taken as inputs, values for the more elusive bulk viscosity ηb for the gases are derived by optimizing the model to the measurements. It is verified that the bulk viscosity parameters obtained from previous experiments at 366 nm are valid for wavelengths of 403 nm. Also for air, which is treated as a single-component gas with effective gas transport coefficients, the Tenti S6 treatment is validated for 403 nm as for the previously used wavelength of 366 nm, yielding an accurate model description of the scattering profiles for a range of temperatures and pressures, including those of relevance for atmospheric studies. It is concluded that the Tenti S6 model, further verified in the present study, is applicable to LIDAR applications for exploring the wind velocity and the temperature profile distributions of the

  19. Correction of radiation absorption on biological samples using Rayleigh to Compton scattering ratio

    NASA Astrophysics Data System (ADS)

    Pereira, Marcelo O.; Conti, Claudio de Carvalho; dos Anjos, Marcelino J.; Lopes, Ricardo T.

    2012-06-01

    The aim of this work was to develop a method to correct the absorbed radiation (the mass attenuation coefficient curve) in low energy (E < 30 keV) applied to a biological matrix based on the Rayleigh to Compton scattering ratio and the effective atomic number. For calibration, scattering measurements were performed on standard samples of radiation produced by a gamma-ray source of 241Am (59.54 keV) also applied to certified biological samples of milk powder, hay powder and bovine liver (NIST 1557B). In addition, six methods of effective atomic number determination were used as described in literature to determinate the Rayleigh to Compton scattering ratio (R/C), in order to calculate the mass attenuation coefficient. The results obtained by the proposed method were compared with those obtained using the transmission method. The experimental results were in good agreement with transmission values suggesting that the method to correct radiation absorption presented in this paper is adequate for biological samples.

  20. Size Estimation and Time Evolution of Large Size Rare Gas Clusters by Rayleigh Scattering Techniques

    NASA Astrophysics Data System (ADS)

    Liu, Bing-Chen; Zhu, Pin-Pin; Li, Zhao-Hui; Ni, Guo-Quan; Xu, Zhi-Zhan

    2002-05-01

    Large rare gas clusters Arn, Krn and Xen were produced at room temperature in the process of supersonic adiabatic expansion. The cluster size is examined by a Rayleigh scattering experiment. Power variations of the average cluster size 0256-307X/19/5/316/art16 with the gas backing pressure P0 give size scaling as 0256-307X/19/5/316/art16 ∝P02.0, resulting in the largest cluster sizes which are estimated in the present work to be about 1.5×104, 2.6×104 and 4.0×104 atoms (the corresponding diameters of the cluster spheres are about 9, 13 and 17 nm) for Ar, Kr and Xe, respectively. A time resolving Rayleigh scattering experiment was conducted to investigate the time evolution of cluster formation and decay processes. A surprising two-plateau structure of the time evolution characteristic of cluster formation and decay processes of Kr and Xe clusters was revealed as compared with a ``normal'' single structure for the case of Ar gas. In the second plateau, the intensity of the scattered light is enhanced greatly, by even as much as 62 times, over that in the first plateau, indicating a significant increase in cluster size. This finding supports the importance of nuclei in the gas condensation process and may be helpful for further insight into the phenomenon of clustering.

  1. Molecular Rayleigh Scattering Diagnostic for Dynamic Temperature, Velocity, and Density Measurements

    NASA Technical Reports Server (NTRS)

    Mielke, Amy R.; Elam, Kristie A.; Sung, Chi-Jen

    2006-01-01

    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations.

  2. Rayleigh Scattering Diagnostic for Measurement of Temperature, Velocity, and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 10 kHz. A high power CW laser beam is focused at a point in a heated air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature, velocity, and density of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 10 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. Power spectral density calculations of temperature, velocity, and density fluctuations, as well as mean and fluctuating quantities are demonstrated for various radial locations in the jet flow at a fixed axial distance from the jet exit plane. Results are compared with constant current anemometry and pitot probe measurements at the same locations.

  3. The application of laser Rayleigh scattering to a reciprocating model engine

    SciTech Connect

    Arcoumains, C.; Green, H.G.; Whitelaw, J.H.

    1984-02-01

    The Rayleigh light scattering technique has been used to quantify the mean and fluctuating concentration of a passive scalar used to simulate fuel injection in a reciprocating, two-stroke model engine motored at 200 rpm in the absence of compression. The transient concentration field, which results from injection of Freon-12 vapour through the centre of an axisymmetrically located permanently open valve, has been investigated for injection timings of 40 deg. before and at top-dead-centre as a function of spatial position and crank angle. The purpose-built Rayleigh system, with gated digital data acquisition and software dust particle filtering, was first evaluated in a Freon-12 free jet by comparing results to those obtained with a sampling probe. At low concentration fluctuations and independent of particle density the agreement between the two methods is excellent but at high concentration fluctuations and particle density the Rayleigh system overestimates the Freon-12 mole fraction by up to about 10% for reasons which are discussed. The results obtained in the model engine indicate that the Freon-12 concentration field expressed in terms of ensemble-averaged mole fractions and rms of concentration fluctuations, is dominated by the high momentum transient jet which, in the near field, exhibits similar trends to the steady jet. Impingement of the jet onto the flat piston improves mixing giving rise to nearly uniform concentration fluctuations of about 10%.

  4. Time-Average Measurement of Velocity, Density, Temperature, and Turbulence Using Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Krisie A.; Panda, Jayanta

    2004-01-01

    Measurement of time-averaged velocity, density, temperature, and turbulence in gas flows using a nonintrusive, point-wise measurement technique based on molecular Rayleigh scattering is discussed. Subsonic and supersonic flows in a 25.4-mm diameter free jet facility were studied. The developed instrumentation utilizes a Fabry-Perot interferometer to spectrally resolve molecularly scattered light from a laser beam passed through a gas flow. The spectrum of the scattered light contains information about velocity, density, and temperature of the gas. The technique uses a slow scan, low noise 16-bit depth CCD camera to record images of the fringes formed by Rayleigh scattered light passing through the interferometer. A kinetic theory model of the Rayleigh scattered light is used in a nonlinear least squares fitting routine to estimate the unknown parameters from the fringe images. The ability to extract turbulence information from the fringe image data proved to be a challenge since the fringe is broadened by not only turbulence, but also thermal fluctuations and aperture effects from collecting light over a range of scattering angles. Figure 1 illustrates broadening of a Rayleigh spectrum typical of flow conditions observed in this work due to aperture effects and turbulence for a scattering angle, chi(sub s), of 90 degrees, f/3.67 collection optics, mean flow velocity, u(sub k), of 300 m/s, and turbulent velocity fluctuations, sigma (sub uk), of 55 m/s. The greatest difficulty in processing the image data was decoupling the thermal and turbulence broadening in the spectrum. To aid in this endeavor, it was necessary to seed the ambient air with smoke and dust particulates; taking advantage of the turbulence broadening in the Mie scattering component of the spectrum of the collected light (not shown in the figure). The primary jet flow was not seeded due to the difficulty of the task. For measurement points lacking particles, velocity, density, and temperature

  5. A Dual-Line Detection Rayleigh Scattering Diagnostic Technique for the Combustion of Hydrocarbon Fuels and Filtered UV Rayleigh Scattering for Gas Velocity Measurements

    NASA Technical Reports Server (NTRS)

    Otugen, M. Volkan

    1997-01-01

    Non-intrusive techniques for the dynamic measurement of gas flow properties such as density, temperature and velocity, are needed in the research leading to the development of new generation high-speed aircraft. Accurate velocity, temperature and density data obtained in ground testing and in-flight measurements can help understand the flow physics leading to transition and turbulence in supersonic, high-altitude flight. Such non-intrusive measurement techniques can also be used to study combustion processes of hydrocarbon fuels in aircraft engines. Reliable, time and space resolved temperature measurements in various combustor configurations can lead to a better understanding of high temperature chemical reaction dynamics thus leading to improved modeling and better prediction of such flows. In view of this, a research program was initiated at Polytechnic University's Aerodynamics Laboratory with support from NASA Lewis Research Center through grants NAG3-1301 and NAG3-1690. The overall objective of this program has been to develop laser-based, non-contact, space- and time-resolved temperature and velocity measurement techniques. In the initial phase of the program a ND:YAG laser-based dual-line Rayleigh scattering technique was developed and tested for the accurate measurement of gas temperature in the presence of background laser glare. Effort was next directed towards the development of a filtered, spectrally-resolved Rayleigh/Mie scattering technique with the objective of developing an interferometric method for time-frozen velocity measurements in high-speed flows utilizing the uv line of an ND:YAG laser and an appropriate molecular absorption filter. This effort included both a search for an appropriate filter material for the 266 nm laser line and the development and testing of several image processing techniques for the fast processing of Fabry-Perot images for velocity and temperature information. Finally, work was also carried out for the development of

  6. The application of laser Rayleigh scattering to gas density measurements in hypersonic helium flows

    NASA Technical Reports Server (NTRS)

    Hoppe, J. C.; Honaker, W. C.

    1979-01-01

    Measurements of the mean static free-stream gas density have been made in two Langley Research Center helium facilities, the 3-inch leg of the high-Reynolds-number helium complex and the 22-inch hypersonic helium tunnel. Rayleigh scattering of a CW argon ion laser beam at 514.5 nm provided the basic physical mechanism. The behavior of the scattered signal was linear, confirmed by a preliminary laboratory study. That study also revealed the need to introduce baffles to reduce stray light. A relatively simple optical system and associated photon-counting electronics were utilized to obtain data for densities from 10 to the 23rd to 10 to the 25th per cu m. The major purpose, to confirm the applicability of this technique in the hypersonic helium flow, was accomplished.

  7. Long-range orientation correlation in dipolar liquids probed by hyper-Rayleigh scattering.

    PubMed

    Shelton, David P

    2015-10-01

    Hyper-Rayleigh scattering (HRS) is sensitive to long-range molecular orientation correlation in isotropic liquids composed of dipolar molecules. The correlation functions that appear in the calculation of HRS mediated by the vector part of the first hyperpolarizability β are the same as the correlation functions for the homogeneous isotropic random vector fields that appear in the description of fluid turbulence. Recent experiments measuring the angle and polarization dependence of HRS from water find a dominant transverse mode contribution with amplitude independent of the scattering wavevector, and this observation of transverse mode HRS strongly constrains the form of the orientation correlation function. Analysis of these HRS results for water determines that the long-range molecular orientation correlation function varies as r(-3±ε) with |ε| < 0.03 on spatial scales up to 2000 nm. PMID:26450319

  8. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    SciTech Connect

    Nedanovska, E.; Nersisyan, G.; Lewis, C. L. S.; Riley, D.; Graham, W. G.; Morgan, T. J.; Hüwel, L.; Murakami, T.

    2015-01-07

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 10{sup 17 }cm{sup −3} to 9 × 10{sup 13 }cm{sup −3}, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t{sup 0.4} consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He{sub 2}{sup +} molecular ion play an important role.

  9. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    NASA Astrophysics Data System (ADS)

    Nedanovska, E.; Nersisyan, G.; Morgan, T. J.; Hüwel, L.; Murakami, T.; Lewis, C. L. S.; Riley, D.; Graham, W. G.

    2015-01-01

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 1017 cm-3 to 9 × 1013 cm-3, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ˜ t0.4 consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He2+ molecular ion play an important role.

  10. Resonance Rayleigh scattering technology as a new method for the determination of the inclusion constant of β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Li, Nianbing; Luo, Hongqun; Liu, Shaopu; Chen, Guonan

    2002-02-01

    The interaction of procaine hydrochloride and β-cyclodextrin in aqueous solution was studied using resonance Rayleigh scattering technology. The molar ratio of the inclusion complex was 1:1 established by spectrophotometry. The resonance Rayleigh scattering technology was first applied in the determination of the β-cyclodextrin inclusion constant. The inclusion constant of procaine hydrochloride-β-cyclodextrin complex Kf is 1.23×10 2 and 1.27×10 2 l mol -1 for method I and 1.15×10 2 and 1.21×10 2 l mol -1 for method II. These determination results were in correspondence with the results of the spectrophotometric and fluorescence methods. Therefore, the resonance Rayleigh scattering method can be used as a new technology for the determination of the inclusion constant.

  11. Direct-View Multi-Point Two-Component Interferometric Rayleigh Scattering Velocimeter

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Gaffney, Richard L., Jr.; Cutler, Andrew D.

    2008-01-01

    This paper describes an instantaneous velocity measurement system based on the Doppler shift of elastically scattered laser light from gas molecules (Rayleigh scattering) relative to an incident laser. The system uses a pulsed laser as the light source, direct-viewing optics to collect the scattered light, an interferometer to analyze spectrally the scattered light mixed with the incident laser light, and a CCD camera to capture the resulting interferogram. The system is capable of simultaneous, spatially (approximately 0.2 mm(exp 3)) and temporally (approximately 40 ns) resolved, multiple point measurements of two orthogonal components of flow velocity in the presence of background scattered light, acoustic noise and vibrations, and flow particulates. Measurements in a large-scale axi-symmetric Mach 1.6 H2-air combustion-heated jet running at a flow sensible enthalpy specific to Mach 5.5 hypersonic flight are performed to demonstrate the technique. The measurements are compared with CFD calculations using a finite-volume discretization of the Favre-averaged Navier-Stokes equations (VULCAN code).

  12. Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air, and moist air.

    PubMed

    Witschas, Benjamin; Vieitez, Maria O; van Duijn, Eric-Jan; Reitebuch, Oliver; van de Water, Willem; Ubachs, Wim

    2010-08-01

    Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh-Brillouin scattering measurements in the ultraviolet at a scattering angle of 90 degrees on N(2) and on dry and moist air. The measured line shapes are compared to the Tenti S6 model, which is shown to describe the scattering line shapes in air at atmospheric pressures with small but significant deviations. We demonstrate that the line profiles of N(2) and air under equal pressure and temperature conditions differ significantly, and that this difference can be described by the S6 model. Moreover, we show that even a high water vapor content in air up to a volume fraction of 3.6vol.% has no influence on the line shape of the scattered light. The results are of relevance for the future spaceborne lidars on ADM-Aeolus (Atmospheric Dynamics Mission) and EarthCARE (Earth Clouds, Aerosols, and Radiation Explorer). PMID:20676176

  13. Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air, and moist air.

    PubMed

    Witschas, Benjamin; Vieitez, Maria O; van Duijn, Eric-Jan; Reitebuch, Oliver; van de Water, Willem; Ubachs, Wim

    2010-08-01

    Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh-Brillouin scattering measurements in the ultraviolet at a scattering angle of 90 degrees on N(2) and on dry and moist air. The measured line shapes are compared to the Tenti S6 model, which is shown to describe the scattering line shapes in air at atmospheric pressures with small but significant deviations. We demonstrate that the line profiles of N(2) and air under equal pressure and temperature conditions differ significantly, and that this difference can be described by the S6 model. Moreover, we show that even a high water vapor content in air up to a volume fraction of 3.6vol.% has no influence on the line shape of the scattered light. The results are of relevance for the future spaceborne lidars on ADM-Aeolus (Atmospheric Dynamics Mission) and EarthCARE (Earth Clouds, Aerosols, and Radiation Explorer).

  14. Demonstration of Imaging Flow Diagnostics Using Rayleigh Scattering in Langley 0.3-Meter Transonic Cryogenic Tunnel

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Herring, G. C.; Barros, Toya

    1999-01-01

    The feasibility of using the Rayleigh scattering technique for molecular density imaging of the free-stream flow field in the Langley 0.3-Meter Transonic Cryogenic Tunnel has been experimentally demonstrated. The Rayleigh scattering was viewed with a near-backward geometry with a frequency-doubled output from a diode-pumped CW Nd:YAG laser and an intensified charge-coupled device camera. Measurements performed in the range of free-stream densities from 3 x 10(exp 25) to 24 x 10(exp 25) molecules/cu m indicate that the observed relative Rayleigh signal levels are approximately linear with flow field density. The absolute signal levels agree (within approx. 30 percent) with the expected signal levels computed based on the well-known quantities of flow field density, Rayleigh scattering cross section for N2, solid angle of collection, transmission of the optics, and the independently calibrated camera sensitivity. These results show that the flow field in this facility is primarily molecular (i.e., not contaminated by clusters) and that Rayleigh scattering is a viable technique for quantitative nonintrusive diagnostics in this facility.

  15. Rayleigh theory of ultrasound scattering applied to liquid-filled contrast nanoparticles

    NASA Astrophysics Data System (ADS)

    Flegg, M. B.; Poole, C. M.; Whittaker, A. K.; Keen, I.; Langton, C. M.

    2010-06-01

    We present a novel modified theory based upon Rayleigh scattering of ultrasound from composite nanoparticles with a liquid core and solid shell. We derive closed form solutions to the scattering cross-section and have applied this model to an ultrasound contrast agent consisting of a liquid-filled core (perfluorooctyl bromide, PFOB) encapsulated by a polymer shell (poly-caprolactone, PCL). Sensitivity analysis was performed to predict the dependence of the scattering cross-section upon material and dimensional parameters. A rapid increase in the scattering cross-section was achieved by increasing the compressibility of the core, validating the incorporation of high compressibility PFOB; the compressibility of the shell had little impact on the overall scattering cross-section although a more compressible shell is desirable. Changes in the density of the shell and the core result in predicted local minima in the scattering cross-section, approximately corresponding to the PFOB-PCL contrast agent considered; hence, incorporation of a lower shell density could potentially significantly improve the scattering cross-section. A 50% reduction in shell thickness relative to external radius increased the predicted scattering cross-section by 50%. Although it has often been considered that the shell has a negative effect on the echogeneity due to its low compressibility, we have shown that it can potentially play an important role in the echogeneity of the contrast agent. The challenge for the future is to identify suitable shell and core materials that meet the predicted characteristics in order to achieve optimal echogenity.

  16. Instantaneous 2D Velocity and Temperature Measurements in High Speed Flows Based on Spectrally Resolved Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1995-01-01

    A Rayleigh scattering diagnostic for high speed flows is described for the simultaneous, instantaneous measurement of gas temperature and velocity at a number (up to about one hundred) of locations in a plane illuminated by an injection-seeded, frequency doubled Nd:YAG laser. Molecular Rayleigh scattered light is collected and passed through a planar mirror Fabry-Perot interferometer. The resulting image is analyzed to determine the gas temperature and bulk velocity at each of the regions. The Cramer Rao lower bound for measurement uncertainty is calculated. Experimental data is presented for a free jet and for preliminary measurements in the Lewis 4 inch by 10 inch supersonic wind tunnel.

  17. Spatially and Temporally-Resolved Multi-Parameter Interferometric Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.

    2011-01-01

    A novel approach to simultaneously measure the translational temperature, bulk velocity, and density in gases by collecting, referencing, and analyzing nanosecond time-scale Rayleigh scattered light from molecules is described. A narrow-band pulsed laser source is used to probe two largely separated measurement locations, one of which is used for reference. The elastically scattered photons containing information from both measurement locations are collected at the same time and analyzed spectrally using a planar Fabry - Perot interferometer. A practical means of referencing the measurement of velocity using the laser frequency, and the density and temperature using the information from the reference measurement location maintained at constant properties is described. To demonstrate the technique single-shot spectra of elastic scattered light are obtained in a near zero velocity H2-air Hencken burner flame and simultaneously in an N2-filled gas cell. A simplified Gaussian distribution model to the scattered light spectra is used to obtain the flame properties. Corrections to this model are applied at lower gas temperatures when the simplified Gaussian approximation is no longer suitable. The near-zero measured velocity as a function of the measured flame temperature, and a comparison of the measured flame density and temperature with the perfect gas law are presented.

  18. What is the contribution of scattering to the Love-to-Rayleigh ratio in ambient microseismic noise?

    NASA Astrophysics Data System (ADS)

    Ziane, D.; Hadziioannou, C.

    2015-12-01

    Several observations show the existence of both Rayleigh and Love waves in the secondary microseism. While the Rayleigh wave excitation is well described by Longuet-Higgins, the process responsible for Love wave generation still needs further investigation. Several different mechanisms could excite Love waves in this frequency band: broadly speaking, we can differentiate between source effects, like pressure variations on the oblique sea floor, or internal effects in the medium along the propagation path, such as scattering and conversions. Here we will focus on the internal effects. We perform single scattering tests in 2D and 3D to gain a better understanding of the scattering radiation pattern and the conversion between P, S, Rayleigh and Love waves. Furthermore, we use random media with continuous variations of the elastic parameters to create a scattering regime similar to the Earths interior, e.g. Gaussian or von Karmann correlation functions. The aim is to explore the contribution of scattering along the propagation path to the observed Love to Rayleigh wave energy ratios, assuming a purely vertical force source mechanism. We use finite different solvers to calculate the synthetic seismograms, and to separate the different wave types we measure the rotational and divergent components of the wave field.

  19. A High Performance Computing approach to model multiple Rayleigh scattering in the Earth atmosphere

    NASA Astrophysics Data System (ADS)

    Franssens, Ghislain; Dekemper, Emmanuel; Mateshivili, Nina; Vanhellemont, filip; fussen, didier; pieroux, didier

    2016-04-01

    The retrieval of atmospheric trace gases and aerosols in the Earth atmosphere from light scattering measurements typically involves an iterative inversion algorithm. A key part of this algorithm is its forward model, which takes care of calculating the amount of light that the remote sensing instrument will see, for any assumed atmosphere composition. The forward model is usually an atmospheric radiative transfer code. It is a serious challenge for a radiative transfer code to be, at the same time, sufficiently accurate and sufficiently fast, so that it can be included in the iterative retrieval loop of an operational service. An accurate code must be able to calculate multiple Rayleigh scattering (important in the UV and/or at lower altitudes) by the air in a spherical atmosphere. This is something that currently only a Monte Carlo algorithm can do. However, any Monte Carlo code is far too slow to be included in the retrieval loop, even if we make use of the currently available HPC power. We report some first results that were obtained by a new solution to this old problem. We first use a HPC cluster to tabulate multiple Rayleigh scattering in a standard Earth atmosphere, using a Monte Carlo code, as function of 6 parameters (albedo, view zenith angle, solar zenith angle, relative azimuth angle, altitude and wavelength). Then, a well chosen empirical function is fitted on the tabulated data. From this function, correction factors are derived and appropriately inserted in a fast single scattering algorithm, which so effectively becomes a multiple scattering algorithm. Since the evaluation of the empirical function is also very fast, we end up with a radiative transfer code that is both accurate and sufficiently fast for operational data production. Our conclusion is that commonly available and affordable HPC systems can still not directly solve the retrieval problem with sufficient accuracy in real time. However, the above described two step approach now becomes

  20. Highly sensitive detection of chromium (III) ions by resonance Rayleigh scattering enhanced by gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Min; Cai, Huai-Hong; Yang, Fen; Lin, Dewen; Yang, Pei-Hui; Cai, Jiye

    2014-01-01

    Simple and sensitive determination of chromium (III) ions (Cr3+) has potential applications for detecting trace contamination in environment. Here, the assay is based on the enhancement of resonance Rayleigh scattering (RRS) by Cr3+-induced aggregation of citrate-capped gold nanoparticles (AuNPs). Transmission electron microscopy (TEM) and UV-vis absorption spectroscopy were employed to characterize the nanostructures and spectroscopic properties of the Cr3+-AuNP system. The experiment conditions, such as reaction time, pH value, salt concentration and interfering ions, were investigated. The combination of signal amplification of Cr3+-citrate chelation with high sensitivity of RRS technique allow a selective assay of Cr3+ ions with a detection limit of up to 1.0 pM. The overall assay can be carried out at room temperature within only twenty minutes, making it suitable for high-throughput routine applications in environment and food samples.

  1. A method of atmospheric density measurements during space shuttle entry using ultraviolet-laser Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1988-01-01

    An analytical study and its experimental verification are described which show the performance capabilities and the hardware requirements of a method for measuring atmospheric density along the Space Shuttle flightpath during entry. Using onboard instrumentation, the technique relies on Rayleigh scattering of light from a pulsed ArF excimer laser operating at a wavelength of 193 nm. The method is shown to be capable of providing density measurements with an uncertainty of less than 1 percent and with a spatial resolution along the flightpath of 1 km, over an altitude range from 50 to 90 km. Experimental verification of the signal linearity and the expected signal-to-noise ratios is demonstrated in a simulation facility at conditions that duplicate the signal levels of the flight environment.

  2. Superradiant rayleigh scattering and collective atomic recoil lasing in a ring cavity.

    PubMed

    Slama, S; Bux, S; Krenz, G; Zimmermann, C; Courteille, Ph W

    2007-02-01

    Collective interaction of light with an atomic gas can give rise to superradiant instabilities. We experimentally study the sudden buildup of a reverse light field in a laser-driven high-finesse ring cavity filled with ultracold thermal or Bose-Einstein condensed atoms. While superradiant Rayleigh scattering from atomic clouds is normally observed only at very low temperatures (i.e., well below 1 microK), the presence of the ring cavity enhances cooperativity and allows for superradiance with thermal clouds as hot as several 10 microK. A characterization of the superradiance at various temperatures and cooperativity parameters allows us to link it to the collective atomic recoil laser.

  3. Molecular Rayleigh Scattering Techniques Developed for Measuring Gas Flow Velocity, Density, Temperature, and Turbulence

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta

    2005-01-01

    Nonintrusive optical point-wise measurement techniques utilizing the principles of molecular Rayleigh scattering have been developed at the NASA Glenn Research Center to obtain time-averaged information about gas velocity, density, temperature, and turbulence, or dynamic information about gas velocity and density in unseeded flows. These techniques enable measurements that are necessary for validating computational fluid dynamics (CFD) and computational aeroacoustic (CAA) codes. Dynamic measurements allow the calculation of power spectra for the various flow properties. This type of information is currently being used in jet noise studies, correlating sound pressure fluctuations with velocity and density fluctuations to determine noise sources in jets. These nonintrusive techniques are particularly useful in supersonic flows, where seeding the flow with particles is not an option, and where the environment is too harsh for hot-wire measurements.

  4. A nanogold resonance Rayleigh scattering method for determination of trace As based on the hydride nanoreaction.

    PubMed

    Jiang, Caina; Chen, Chunqiang; Lu, Zujun; Liu, Qingye; Tang, Meiling; Liang, Aihui; Jiang, Zhiliang

    2015-09-01

    In H2 SO4 solution, As(III) was reduced to arsine (AsH3 ) by NaBH4 , and was absorbed in HAuCl4 solution to form nanogold particles (NGs) that exhibited a resonance Rayleigh scattering (RRS) effect at 370 nm. Under the selected conditions, when the As(III) concentration increased the RRS peak also increased due to the formation of more NGs. There was a linear correlation between RRS intensity and As(III) concentration in the range 6-1000 ng/mL, with a detection limit of 3 ng/mL. This new hydride generation-nanogold reaction RRS (HG-NG RRS) method was applied to determine trace amounts of As in milk samples, with satisfactory results.

  5. A new resonance Rayleigh scattering spectral method for determination of O3 with victoria blue B

    NASA Astrophysics Data System (ADS)

    Wen, Guiqing; Yang, Duo; Jiang, Zhiliang

    2014-01-01

    Ozone (O3) could be absorbed by boric acid-potassium iodide (BKI) absorbent solution to produce tri-iodine ion (I3-) that react with victoria blue B (VBB) to form the associated particle (VBB-I3)n and exhibited a strong resonance Rayleigh scattering (RRS) peak at 722 nm. Under the chosen conditions, the RRS peak intensity was linear with O3 concentration in the range of 0.2-50 μmol/L, with a linear regression equation of ΔI722 = 17.9c - 45.4 and detection limit of 0.057 μmol/L. Accordingly, a simple, rapid and sensitive RRS spectral method was set up for determination of trace O3 in air, with satisfactory results.

  6. The development of a tunable, single-frequency ultraviolet laser source for UV filtered Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Finkelstein, N.; Gambogi, J.; Lempert, Walter R.; Miles, Richard B.; Rines, G. A.; Finch, A.; Schwarz, R. A.

    1995-01-01

    We present the development of a flexible, high power, narrow line width, tunable ultraviolet source for diagnostic application. By frequency tripling the output of a pulsed titanium-sapphire laser, we achieve broadly tunable (227-360 nm) ultraviolet light with high quality spatial and spectral resolution. We also present the characterization of a mercury vapor cell which provides a narrow band, sharp edge absorption filter at 253.7 nm. These two components form the basis for the extension of the Filtered Rayleigh Scattering technique into the ultraviolet. The UV-FRS system is comprised of four pieces: a single frequency, cw tunable Ti:Sapphire seeding source; a high-powered pulsed Ti:Sapphire oscillator; a third harmonic generator system; and an atomic mercury vapor filter. In this paper we discuss the development and characterization of each of these elements.

  7. Feasibility of Rayleigh Scattering Flow Diagnostics in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Lee, Joseph W.; Goad, William K.

    2015-01-01

    Laser-based Rayleigh light scattering (RLS) was performed in the National Transonic Facility (NTF) at NASA Langley Research Center. The goal was to determine if the free-stream flow undergoes clustering (early stage of condensation from gas to liquid) or remains in a pure diatomic molecular phase. Data indicate that clusters are not observable down to levels of 10% of the total light scatter for a variety of total pressures at one N2 cryogenic-mode total temperature (Tt = -50 F = 227 K) and one air-mode temperature (Tt = +130 F = 327 K). Thus RLS appears viable as a qualitative or quantitative diagnostic for flow density in NTF in the future. Particles are distinguished from optically unresolvable clusters because they are much larger and individually resolvable in the laser beam image with Mie scattering. The same RLS apparatus was also used, without modification, to visualize naturally occurring particles entrained in the flow for both cryogenic and air-modes. Estimates of the free-stream particle flux are presented, which may be important for interpretation of laminar-to-turbulent boundary-layer transition studies. 1

  8. Rayleigh-Brillouin scattering for high-pressure gas temperature measurements

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1991-01-01

    An experiment was set up to evaluate the feasibility of using Rayleigh-Brillouin scattering as a diagnostic technique for measuring gas temperature in high pressure environments, such as the Space Shuttle Main Engine (SSME) Preburner. A high pressure furnace is used as the scattering chamber. Either nitrogen or hydrogen may be used. An argon ion laser beam is focused into the furnace. Light backscattering from the gas in the furnace is collected and analyzed with a 5-pass scanning Fabry-Perot interferometer and photon counting electronics. The multi-pass configuration provides the high frequency selectively needed to measure the Brillouin peaks in the presence of large amounts of spuriously scattered light at the laser frequency. Preliminary measurements were made at room temperature in nitrogen at pressures up to 2000 psia. The free spectral range of the interferometer and frequency separation of the Brillouin peaks are determined from measured spectra. Temperature measurements are then obtained using the simple continuum theory with low frequency values of specific heat ratio and shear viscosity. The measured temperatures are within 10 percent of the true value.

  9. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre.

    PubMed

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-06-16

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre's intrinsically higher Rayleigh scatter signal.

  10. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre

    PubMed Central

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-01-01

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre’s intrinsically higher Rayleigh scatter signal. PMID:26077365

  11. Rayleigh scatter based order of magnitude increase in distributed temperature and strain sensing by simple UV exposure of optical fibre

    NASA Astrophysics Data System (ADS)

    Loranger, Sébastien; Gagné, Mathieu; Lambin-Iezzi, Victor; Kashyap, Raman

    2015-06-01

    We present a technique to improve signal strength, and therefore sensitivity in distributed temperature and strain sensing (DTSS) using Frequency domain Rayleigh scatter. A simple UV exposure of a hydrogen loaded standard SMF-28 fibre core is shown to enhance the Rayleigh back-scattered light dramatically by ten-fold, independent of the presence of a Bragg grating, and is therefore created by the UV exposure alone. This increase in Rayleigh back-scatter allows an order-of-magnitude increase in temperature and strain resolution for DTSS compared to un-exposed SMF-28 fibre used as a sensing element. This enhancement in sensitivity is effective for cm range or more sensor gauge length, below which is the theoretical cross-correlation limit. The detection of a 20 mK temperature rise with a spatial resolution of 2 cm is demonstrated. This gain in sensitivity for SMF-28 is compared with a high Ge doped photosensitive fibre with a characteristically high NA. For the latter, the UV enhancement is also present although of lower amplitude, and enables an even lower noise level for sensing, due to the fibre’s intrinsically higher Rayleigh scatter signal.

  12. Ultrasensitive detection of target analyte-induced aggregation of gold nanoparticles using laser-induced nanoparticle Rayleigh scattering.

    PubMed

    Lin, Jia-Hui; Tseng, Wei-Lung

    2015-01-01

    Detection of salt- and analyte-induced aggregation of gold nanoparticles (AuNPs) mostly relies on costly and bulky analytical instruments. To response this drawback, a portable, miniaturized, sensitive, and cost-effective detection technique is urgently required for rapid field detection and monitoring of target analyte via the use of AuNP-based sensor. This study combined a miniaturized spectrometer with a 532-nm laser to develop a laser-induced Rayleigh scattering technique, allowing the sensitive and selective detection of Rayleigh scattering from the aggregated AuNPs. Three AuNP-based sensing systems, including salt-, thiol- and metal ion-induced aggregation of the AuNPs, were performed to examine the sensitivity of laser-induced Rayleigh scattering technique. Salt-, thiol-, and metal ion-promoted NP aggregation were exemplified by the use of aptamer-adsorbed, fluorosurfactant-stabilized, and gallic acid-capped AuNPs for probing K(+), S-adenosylhomocysteine hydrolase-induced hydrolysis of S-adenosylhomocysteine, and Pb(2+), in sequence. Compared to the reported methods for monitoring the aggregated AuNPs, the proposed system provided distinct advantages of sensitivity. Laser-induced Rayleigh scattering technique was improved to be convenient, cheap, and portable by replacing a diode laser and a miniaturized spectrometer with a laser pointer and a smart-phone. Using this smart-phone-based detection platform, we can determine whether or not the Pb(2+) concentration exceed the maximum allowable level of Pb(2+) in drinking water.

  13. Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

    SciTech Connect

    Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.

    2004-01-01

    Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS

  14. Hyper-Rayleigh scattering and hyper-Raman scattering of dye-adsorbed silver nanoparticles induced by a focused continuous-wave near-infrared laser

    SciTech Connect

    Itoh, Tamitake; Ozaki, Yukihiro; Yoshikawa, Hiroyuki; Ihama, Takashi; Masuhara, Hiroshi

    2006-02-20

    We report that hyper-Rayleigh scattering, surface-enhanced hyper-Raman scattering, and two-photon excited luminescence occur intermittently by focusing a continuous-wave near-infrared (cw-NIR) laser into a colloidal silver solution including rhodamine 6G (R6G) and sodium chloride (NaCl). On the other hand, continuous hyper-Rayleigh scattering is observed from colloidal silver free from R6G and NaCl, demonstrating that hyper-Raman scattering and two-photon excited luminescence are attributed to R6G and their intermittent features are dependent on the colloidal dispersion. These results suggest that the cw-NIR laser has three roles; the source of the nonlinear response, optical trapping of nanoparticles, and making nanoparticle aggregates possessing the high activity for the nonlinear response.

  15. Highly efficient and two-photon excited stimulated Rayleigh-Bragg scattering in organic solutions

    SciTech Connect

    He, Guang S. Prasad, Paras N.; Kannan, Ramamurthi; Tan, Loon-Seng

    2015-07-21

    The properties of backward stimulated Rayleigh-Bragg scattering (SRBS) in three highly two-photon active AF-chromophores solutions in tetrahydrofuran (THF) have been investigated using 816-nm and 8-ns pump laser beam. The nonlinear reflectivity R, spectral structure, temporal behavior, and phase-conjugation capability of the backward SRBS output have been measured, respectively. Under the same experimental condition, the pump threshold for SRBS in three solution samples can be significantly (∼one order of magnitude) lower than that for stimulated Brillouin scattering (SBS) in the pure solvent (THF). With the optimized concentration value and at a moderate pump energy (∼1.5 mJ) level, the measured nonlinear reflectivity was R ≥ 35% for the 2 cm-long solution sample, while for the SBS from a pure solvent sample of the same length was R ≈ 4.7%. The peculiar features of very low pump threshold, no spectral shift, tolerant pump spectral linewidth requirement (≤1 cm{sup −1}), and phase-conjugation capability are favorable for those nonlinear photonics applications, such as highly efficiency phase-conjugation reflectors for high-brightness laser oscillator/amplifier systems, special imaging through turbid medium, self-adaptive remote optical sensing, as well as for optical rangefinder and lidar systems.

  16. Using gold nanoparticles as probe for detection of salmeterol xinafoate by resonance Rayleigh light scattering.

    PubMed

    Bi, Shuyun; Wang, Tianjiao; Wang, Yu; Zhao, Tingting; Zhou, Huifeng

    2015-01-25

    The paper explores the method of determination of salmeterol xinafoate at nanogram level with gold nanoparticles (AuNPs) probe, to measure the intensity of resonance Rayleigh light scattering (RLS) by a common spectrofluorometer. The RLS intensity of salmeterol xinafoate was greatly enhanced by AuNPs, with the maximum scattering peak at 357 nm. The salmeterol xinafoate was determined basing on the binding of salmeterol xinafoate to AuNPs by electrostatic adsorption. Under the optimum conditions, the enhanced RLS intensity was directly proportional to the concentration of salmeterol xinafoate in the range of 0.054-6.038 μg mL(-1) with a good linear relationship (r=0.9928). The limit of detection (LOD) was 9.48 ng mL(-1). The interference tests were performed carefully. With the proposed method, the synthetic samples were analyzed satisfactorily, the recovery and RSD were 102.5-103.0% and 0.67-1.0% respectively. PMID:25173524

  17. Determination of surface normal temperature gradients using thermographic phosphors and filtered Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Brübach, J.; Zetterberg, J.; Omrane, A.; Li, Z. S.; Aldén, M.; Dreizler, A.

    2006-09-01

    Wall temperature as well as the temperature distribution within or close-by the boundary layer of an electrically heated axisymmetric jet impinging on a flat plate were monitored to deduce wall-normal temperature gradients. The radial surface temperature profile of the plate was determined by coating it with thermographic phosphors (TPs), materials whose phosphorescence decay time is dependent on their temperature. The TP was excited electronically by a frequency-tripled Nd:YAG laser (355 nm) and the temporal decay of the phosphorescence intensity was measured zero-dimensionally by a photomultiplier tube. In this case the 659-nm emission line of Mg3F2GeO4:Mn was monitored. The non-intrusive measurement of gas temperatures near the surface was performed two-dimensionally by filtered Rayleigh scattering (FRS). A tunable frequency-tripled single-longitudinal-mode alexandrite laser beam at 254 nm was formed into a light sheet pointing parallel to the surface. The scattered light was imaged through a very narrow linewidth atomic mercury filter onto an intensified charged coupled device (ICCD). The elastic stray light from surfaces was strongly suppressed, whereas Doppler-broadened light was detected. Thermographic phosphors proved to be reliable for the measurement of surface temperatures. Dependent on the specific experimental conditions, problems appeared with signals interfering with the FRS radiation close-by the surface. Results and challenges of this approach are discussed.

  18. Absolute Rayleigh scattering cross sections of gases and freons of stratospheric interest in the visible and ultraviolet regions

    NASA Technical Reports Server (NTRS)

    SHARDANAND; Rao, A. D. P.

    1977-01-01

    The laboratory measurements of absolute Rayleigh scattering cross sections as a function wavelength are reported for gas molecules He, Ne, Ar, N2, H2, O2, CO2, CH4 and for vapors of most commonly used freons CCl2F2, CBrF3, CF4, and CHClf2. These cross sections are determined from the measurements of photon scattering at an angle of 54 deg 44 min which yield the absolute values independent of the value of normal depolarization ratios. The present results show that in the spectral range 6943-3638A deg, the values of the Rayleigh scattering cross section can be extrapolated from one wavelength to the other using 1/lambda (4) law without knowing the values of the polarizabilities. However, such an extrapolation can not be done in the region of shorter wavelengths.

  19. [Resonance Rayleigh scattering determination of trace tobramycin using aptamer-modified nanogold as probe ].

    PubMed

    Ma, Lu; Wen, Gui-Qing; Liu, Qing-Ye; Liang, Ai-Hui; Jiang, Zhi-Liang

    2014-09-01

    Nanogold (NG) was prepared using NaBH4 reduction of HAuCl4. The NG was modified by the tobramycin-aptamer to obtain a stable Apt-NG probe for tobramycin. The three aptamers containing 15, 21 and 27 bases were examined, and results showed that the aptamer with 21 bases was best and was chosen for use. In pH 6. 8 PBS buffer solution and in the presence of NaCl, the Apt-GN probes were not aggregated. When tobramycin was added, it reacted with the Apt of Apt-NG probe to form a very stable Apt-Tbc complex and released NGs that were aggregated into big particles under the action of NaCl with three resonance Rayleigh scattering peaks at 285, 368 and 525 nm respectively. The resonance Rayleigh scattering peak increased at 368 nm due to the formation of big NG particles from the probe. The effect of pH buffer solution, its volume, and Apt-GN probe concentration on the ΔI value was considered. A 200 μL pH 6. 8 PBS buffer solution and 19. 1 nmol · L(-3) Apt-GN, giving max ΔI value, were chosen for use. Under the chosen conditions, the increased resonance Rayleigh scattering intensity ΔI368 nm was linear with Tbc concentration in the range of 1.9-58.3 ng mL(-3), with a regress equation of ΔI = 35.3c-23 and a detection limit of 0.8 ng · mL(-3) Tbc. A 10.0, 20.0 and 30.0 ng mL-3 Tbc was determined five times respectively, and the relative standard deviations were 6.8%, 5.0% and 4.4%. The influence of some foreign substances was examined on the determination of 38.9 ng · mL(-3) Tbc, within ±10% related error. Results showed that a 80 times of Zn2+, 40 times of L-glutamic acid, Cu2+, Mg2+ and Ca2+, 20 times of glucose and terramycin, 10 times of L-phenylalanine and glycin, 2 times of L-aspartic acid, and 6 times of bovine serum albumin (BSA) and human serum albumin (HSA) do not interfere with the RRS determination of Tbc. The results showed that this aptamer-nanogold RRS method is of good selectivity. Tbc in real sample was analyzed, and the analytical result was in

  20. Molecular Rayleigh Scattering Diagnostic for Measurement of High Frequency Temperature Fluctuations

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.

    2005-01-01

    A novel technique for measurement of high frequency temperature fluctuations in unseeded gas flows using molecular Rayleigh scattering is investigated. The spectrum of laser light scattered from molecules in a gas flow is resolved using a Fabry-Perot interferometer. The width of the spectral peak is broadened by thermal motion of the molecules and hence is related to gas temperature. The interference fringe pattern containing spectral information is divided into four concentric regions using a series of mirrors angled with respect to one another. Light from each of these regions is directed towards photomultiplier tubes and sampled at 10 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows measurement of gas temperature. Independently monitoring the total scattered intensity provides a measure of gas density. This technique also has the potential to simultaneously measure a single component of flow velocity by monitoring the spectral peak location. Measurements of gas temperature and density are demonstrated using a low speed heated air jet surrounded by an unheated air co-flow. Mean values of temperature and density are shown for radial scans across the jet flow at a fixed axial distance from the jet exit plane. Power spectra of temperature and density fluctuations at several locations in the jet are also shown. The instantaneous measurements have fairly high uncertainty; however, long data records provide highly accurate statistically quantities, which include power spectra. Mean temperatures are compared with thermocouple measurements as well as the temperatures derived from independent density measurements. The accuracy for mean temperature measurements was +/- 7 K.

  1. Comparison of Coincident Rayleigh-Scatter and Sodium Resonance Lidar Temperature Measurements from the Mesosphere-Lower-Thermosphere Region

    NASA Astrophysics Data System (ADS)

    Sox, L.; Wickwar, V. B.; Yuan, T.; Criddle, N.

    2015-12-01

    There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh scatter and resonance lidars, particularly sodium resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics (gravity waves, tides) and long-term temperature trends (upper atmosphere cooling) of the MLT region can be studied. The Utah State University (USU; 41.7º N, 111.8º W) campus hosts a unique upper atmospheric observatory which houses both a high-power, large-aperture Rayleigh lidar and a sodium resonance Doppler lidar. For the first time, we will present coordinated, night-time averaged temperatures, overlapping in observational range (80-110 km), from the two lidars. This overlap has been achieved through the relocation of the sodium lidar from Colorado State University to USU's campus and through upgrades to the existing USU Rayleigh lidar which elevated its observational range from 45-90 km to 70-115 km. The comparison of the two sets of temperature measurements is important because the two lidar techniques derive temperature profiles using different scattering processes and analysis methods. Furthermore, previous climatological comparisons, between Rayleigh and sodium lidar, [Argall and Sica, 2007] have suggested that significant temperature differences can occur. This comparison aims to explore possible temperature effects from the differences in the two measurement techniques.

  2. Resonance Rayleigh scattering method for highly sensitive detection of chitosan using aniline blue as probe.

    PubMed

    Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan

    2016-11-01

    This paper describes a highly sensitive and accurate approach using aniline blue (AB) (water soluble) as a probe to determine chitosan (CTS) through Resonance Rayleigh scattering (RRS). Under optimum experimental conditions, the intensities of RRS were linearly proportional to the concentration of CTS in the range from 0.01 to 3.5μg/mL, and the limit of detection (LOD) was 6.94ng/mL. Therefore, a new and highly sensitive method based on RRS for the determination of CTS has been developed. Furthermore, the effect of molecular weight of CTS and the effect of the degree of deacetylation of CTS on the accurate quantification of CTS was studied. The experimental data was analyzed by linear regression analysis, which indicated that the molecular weight and the degree of deacetylation of CTS had no statistical significance and this method could be used to determine CTS accurately. Meanwhile, this assay was applied for CTS determination in health products with satisfactory results.

  3. Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10

    NASA Technical Reports Server (NTRS)

    Balla, R. Jeffrey; Everhart, Joel L.

    2012-01-01

    In an exploratory investigation, quantitative unclustered laser Rayleigh scattering measurements of density were performed in the air in the NASA Langley Research Center's 31 in. Mach 10 wind tunnel. A review of 20 previous years of data in supersonic and Mach 6 hypersonic flows is presented where clustered signals typically overwhelmed molecular signals. A review of nucleation theory and accompanying nucleation calculations are also provided to interpret the current observed lack of clustering. Data were acquired at a fixed stagnation temperature near 990Kat five stagnation pressures spanning 2.41 to 10.0 MPa (350 to 1454 psi) using a pulsed argon fluoride excimer laser and double-intensified charge-coupled device camera. Data averaged over 371 images and 210 pixels along a 36.7mmline measured freestream densities that agree with computed isentropic-expansion densities to less than 2% and less than 6% at the highest and lowest densities, respectively. Cluster-free Mach 10 results are compared with previous clustered Mach 6 and condensation-free Mach 14 results. Evidence is presented indicating vibrationally excited oxygen and nitrogen molecules are absorbed as the clusters form, release their excess energy, and inhibit or possibly reverse the clustering process. Implications for delaying clustering and condensation onset in hypersonic and hypervelocity facilities are discussed.

  4. A silver nanorod resonance rayleigh scattering-energy transfer analytical platform for trace tea polyphenols.

    PubMed

    Liang, Aihui; Wang, Yaohui; Wen, Guiqing; Zhang, Xinghui; Luo, Yanghe; Jiang, Zhiliang

    2016-04-15

    The stable silver nanorod (AgNR) sol in red was prepared by the two-step procedure of NaBH4-H2O2 and citrate heating reduction, and it exhibited a strong resonance Rayleigh scattering (RRS) peak at 346 nm. In pH 3.8 HAc-NaAc buffer solution, tea polyphenols (TP) reacted with ammonium molybdate (AM) to form yellow organic molybdate (OM) as receptor that was closed to the donor of AgNR, the RRS energy transfer (RRS-ET) takes place, owing to the overlapping between the AgNR RRS spectra and OM absorption spectra. When TP concentration increased, the RRS intensity decreased due to the RRS-ET increasing. So, a simple and sensitive AgNR surface plasmon RRS-ET analytical platform was fabricated to detect trace TP in the range of 0.05-0.85 μg/mL, with a detection limit of 0.03 μg/mL TP. The TP in tea samples was analyzed by this RRS-ET analysis platform, with satisfactory results.

  5. Resonance Rayleigh scattering method for highly sensitive detection of chitosan using aniline blue as probe

    NASA Astrophysics Data System (ADS)

    Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan

    2016-11-01

    This paper describes a highly sensitive and accurate approach using aniline blue (AB) (water soluble) as a probe to determine chitosan (CTS) through Resonance Rayleigh scattering (RRS). Under optimum experimental conditions, the intensities of RRS were linearly proportional to the concentration of CTS in the range from 0.01 to 3.5 μg/mL, and the limit of detection (LOD) was 6.94 ng/mL. Therefore, a new and highly sensitive method based on RRS for the determination of CTS has been developed. Furthermore, the effect of molecular weight of CTS and the effect of the degree of deacetylation of CTS on the accurate quantification of CTS was studied. The experimental data was analyzed by linear regression analysis, which indicated that the molecular weight and the degree of deacetylation of CTS had no statistical significance and this method could be used to determine CTS accurately. Meanwhile, this assay was applied for CTS determination in health products with satisfactory results.

  6. Resonance Rayleigh scattering method for the determination of cationic surfactants with chromium(VI)-iodide system.

    PubMed

    Liu, Shaopu; Shi, Yan; Liu, Zhongfang; Luo, Hongqun; Kong, Ling

    2006-05-01

    A method for detecting and identifying cationic surfactant in some chemical samples for daily use that include Head & Shoulder Ampoule and Slek Shower Lotion has been developed. In an acid medium, chromium(VI) oxidizes I(-) to produce I(2), I(2) binds excess of I(-) to form I(3)(-), and I(3)(-) can further react with a cationic surfactant (CS) (such as cetyldimethyl benzylammonium chloride (CDBAC), Zephiramine (Zeph), cetylpyridinium bromide (CPB), tetradecyl pyridinium bromide (TPB) and cetyltrimethylammonium bromide (CTAB)) to form ion-association complexes [CS][I(3)]. This results in a significant enhancement of resonance Rayleigh scattering (RRS) and appearance of new RRS spectra. The RRS spectral characteristics of the ion-association complexes, the influencing factors and the optimum conditions of the reactions have been investigated. The intensities of RRS are directly proportional to the concentration of CS. CS in samples are collected using a treated anion exchange column and subsequently complexed by I(3)(-); then the RRS intensities of CS complex are determined at 495 nm. The reactions have high sensitivities, and their detection limits are 7.05 - 9.62 ng/mL for different CS. The effects of foreign substances are investigated and the results show that the method has good selectivity.

  7. Determination of thiram using gold nanoparticles and Resonance Rayleigh scattering method.

    PubMed

    Parham, Hooshang; Pourreza, Nahid; Marahel, Farzaneh

    2015-08-15

    A sensitive, simple and novel method was developed to determine thiram fungicide in water and plant samples. This method was based on the interaction between gold nanoparticles (AuNPs) and thiram fungicide followed by increasing of the Resonance Rayleigh scattering (RRS) intensity of nanoparticles. The change in RRS intensity (∆IRRS) was linearly correlated to the concentration of thiram over the range of 1.0-200.0µgL(-1). Thiram can be measured in a short time (4min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RRS intensities such as pH, concentration of AuNPs, standing time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a very good selectivity and could be used conveniently for the determination of thiram. The limit of detection (LOD) and limit of quantification (LOQ) were 0.3 and 1.0µg L(-1), respectively. Relative standard deviations (RSD) for 20.0 and 80.0µg L(-1) of thiram were 3.0 and 1.1, respectively. Possible mechanisms for the RRS changes of AuNPs in the presence of thiram were discussed and the method was successfully applied for the analysis of spiked real water samples and fresh plant samples such as tomato and cucumber.

  8. Characterization of the nonlinear optical properties of nanocrystals by Hyper Rayleigh Scattering

    PubMed Central

    2013-01-01

    Background Harmonic Nanoparticles are a new family of exogenous markers for multiphoton imaging exerting optical contrast by second harmonic (SH) generation. In this tutorial, we present the application of Hyper-Rayleigh Scattering (HRS) for a quantitative assessment of the nonlinear optical properties of these particles and discuss the underlying theory and some crucial experimental aspects. Methods The second harmonic properties of BaTiO3, KNbO3, KiTiOPO4 (KTP), LiNbO3 and ZnO nanocrystals (NCs) are investigated by HRS measurements after careful preparation and characterization of colloidal suspensions. Results A detailed analysis of the experimental results is presented with emphasis on the theoretical background and on the influence of some experimental parameters including the accurate determination of the nanocrystal size and concentration. The SH generation efficiency and averaged nonlinear optical coefficients are then derived and compared for six different types of NCs. Conclusions After preparation of colloidal NC suspensions and careful examination of their size, concentration and possible aggregation state, HRS appears as a valuable tool to quantitatively assess the SH efficiency of noncentrosymmetric NCs. All the investigated nanomaterials show high SH conversion efficiencies, demonstrating a good potential for bio-labelling applications. PMID:24564891

  9. A simple and rapid resonance Rayleigh scattering method for detection of indigo carmine in soft drink.

    PubMed

    Li, Qin; Yang, Jidong; Tan, Xuanping; Zhang, Zhan; Hu, Xiaomei; Yang, Menghuan

    2016-08-01

    A novel method that uses acridine orange (AO) to detect indigo carmine (IC) in soft drinks was developed. The method is highly sensitive and is based on a resonance Rayleigh scattering (RRS) technique. In Britton-Robinson (BR) buffer solution, pH 4.3, the weak RRS intensity of AO was greatly enhanced by the addition of IC, with the maximum peak located at 332 nm. Under optimum conditions, it was found that the enhanced RRS intensity was proportional to the concentration of IC over a range of 2-32 × 10(-6)  mol/L. A low detection limit of 2.4 × 10(-8)  mol/L was achieved. The sensitivity and selectivity of the method are high enough to permit the determination of trace amounts of IC without any significant interference from high levels of other components such as common anions and other amino acids. Finally, the concentration of IC in three different soft drinks was determined with satisfactory results. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26791156

  10. Verification of radiative transfer results by inserting them into the RTE: A demonstration for Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Hollstein, André

    2012-10-01

    The verification of a new or updated radiative transfer model (RTM) is one of the important steps in its development; this is usually achieved by comparisons with real measurements or published tables of generally accepted radiative transfer results. If such tables do not exist, verification becomes more complicated and an external review of the implementation is often unpractical due to the sheer amount and complexity of the code. The presented verification approach is to “simply” insert results of radiative transfer (RT) calculations into the radiative transfer equation (RTE). The evaluation of the RTE consists of numerically calculating partial derivatives and integrals, which is much simpler to implement than a solution of the RTE. Presented is a demonstration of this approach for a case of Rayleigh scattering in a plane parallel atmosphere, which showed only very small deviation from the radiative transfer equation.This approach has two key benefits. First, its implementation into a high level computer language can be very short (≈60 lines in MATHEMATICA) and clear compared to a full RTM; and such code is much more easy to review. Second, this approach can be easily extended to cases where no other independent RT implementation is available for validation. The proposed implementation and data are provided with this paper.

  11. Resonance Rayleigh scattering study of interaction of heparin with some cationic surfactants and their analytical application

    NASA Astrophysics Data System (ADS)

    Liu, Shao Pu; Luo, Hong Qun; Xu, Hong; Li, Nian Bing

    2005-03-01

    Binding of heparin with a cationic surfactant such as cetyldimethyl benzylammonium chloride (CDBAC), tetradecyldimethyl benzylammonium chloride (Zeph), cetylpyridinium bromide (CPB), tetradecane pyridinium bromide (TPB) and cetyltrimethylammonium bromide (CTAB) in a near-neutral medium can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensities. The results showed that the reaction conditions and RRS spectral characteristics of these reactions are similar, but their sensitivities are obviously different. Among them, the sensitivity of CDBAC with an aryl and large molecular weight is the highest, while that of CTAB without aryl and with small molecular weight is the lowest. The detection limit for heparin of the former is 11 ng ml -1 while that of the latter is 33 ng ml -1. The method has better selectivity and was applied to the determination of trace amounts of heparin in sodium heparin injection samples with satisfactory results. Furthermore, it is discovered that the RRS intensity is related to the structure and molecular weight of the cationic surfactant.

  12. Amplification of resonant Rayleigh light scattering response using immunogold colloids for detection of lysozyme.

    PubMed

    Truong, Phuoc Long; Choi, Seung Phill; Sim, Sang Jun

    2013-10-25

    A strategy for attomolar-level detection of small molecule-size proteins is reported based on Rayleigh light scattering spectroscopy of individual nanoplasmonic aptasensors by exploiting the outstanding characteristics of gold colloids to amplify the nontransparent resonant signal at ultralow analyte concentrations. The fabrication method utilizes thiol-mediated adsorption of a DNA aptamer on the immobilized Au nanoparticle surface, the interfacial binding characteristics of the aptamer with its target molecules, and the antibody-antigen interaction through plasmonic resonance coupling of the Au nanoparticles. Using lysozyme as a model analyte for disease detection, the detection limit of the aptasensor is ∼7 × 10(3) aM, corresponding to the LSPR λmax shift of ∼2.25 nm. Up to a 380% increase in the localized resonant λmax shift is demonstrated upon antibody binding to the analyte compared to the primary response during signal amplification using immunogold colloids. This enhancement leads to a limit of detection of ∼7 aM, which is an improvement of three orders of magnitude. The results demonstrate substantial promise for developing coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes.

  13. Pulsed laser Rayleigh scattering diagnostic for hydrogen/oxygen rocket exit plane flowfield velocimetry

    NASA Technical Reports Server (NTRS)

    Zupanc, Frank J.

    1993-01-01

    A Doppler-resolved, pulsed laser Rayleigh scattering diagnostic has been developed to obtain local flowfield velocity measurements at the exit plane of a low thrust hydrogen/oxygen rocket engine operating in a high-altitude test facility. Fiberoptic signal collection was employed to obtain the forescatter and backscatter Doppler shifts necessary to resolve the axial and radial velocity components. A radial profile was obtained by traversing the collection probes along the beam path at the nozzle exit. The results are compared with theoretical predictions from a full Navier-Stokes model (RK/RPLUS). Significant discrepancies between the measured and predicted axial velocity profiles are observed, in terms of both magnitude and character. Radial velocity measurements exhibit excellent agreement with predictions near the centerline but show some departure off-axis. The discrepancies between theory and experiment are potentially the result of enhanced mixing between the core and fuel-film region beyond that predicted, and/or flow stratification between the hydrogen and oxygen injected into the central core region.

  14. Hydride generation-resonance Rayleigh scattering and SERS spectral determination of trace Bi

    NASA Astrophysics Data System (ADS)

    Liang, Xiaojing; Wen, Guiqing; Liu, Qingye; Liang, Aihui; Jiang, Zhiliang

    2016-09-01

    In acidic solutions, Bi(III) was reduced by NaBH4 to form BiH3 gas. Using I3- graphene oxide (GO) as absorption solution, the BiH3 gas reacted with I3- to form I- that resulted in the I3- concentration decreasing. In the absence of BiH3, the I3- concentration was high, and as receptors it was closed to the surfaces of GO which was as donors. Then the surface plasmon resonance Rayleigh scattering (RRS) energy of GO transfers to I3- heavily, and results in the RRS quenching severely. With the increase of the Bi(III) concentration, the receptors and the RRS energy transfer (RRS-ET) decreased, so the RRS intensity enhanced linearly at 370 nm. The RRS intensity was linear to the Bi(III) concentration in 0.05-5.5 μmol/L, with a detection limit of 4 ng/mL Bi. A new RRS-ET spectral method was developed for the determination of trace Bi(III). Using I3- as the absorption solution, silver nanorod (AgNR) as sol substrate and Vitoria blue B (VBB) as molecular probe, a SERS method was developed for detection of Bi.

  15. Resonance Rayleigh scattering method for highly sensitive detection of chitosan using aniline blue as probe.

    PubMed

    Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan

    2016-11-01

    This paper describes a highly sensitive and accurate approach using aniline blue (AB) (water soluble) as a probe to determine chitosan (CTS) through Resonance Rayleigh scattering (RRS). Under optimum experimental conditions, the intensities of RRS were linearly proportional to the concentration of CTS in the range from 0.01 to 3.5μg/mL, and the limit of detection (LOD) was 6.94ng/mL. Therefore, a new and highly sensitive method based on RRS for the determination of CTS has been developed. Furthermore, the effect of molecular weight of CTS and the effect of the degree of deacetylation of CTS on the accurate quantification of CTS was studied. The experimental data was analyzed by linear regression analysis, which indicated that the molecular weight and the degree of deacetylation of CTS had no statistical significance and this method could be used to determine CTS accurately. Meanwhile, this assay was applied for CTS determination in health products with satisfactory results. PMID:27294549

  16. Resonance Rayleigh scattering method for the determination of cationic surfactants with chromium(VI)-iodide system.

    PubMed

    Liu, Shaopu; Shi, Yan; Liu, Zhongfang; Luo, Hongqun; Kong, Ling

    2006-05-01

    A method for detecting and identifying cationic surfactant in some chemical samples for daily use that include Head & Shoulder Ampoule and Slek Shower Lotion has been developed. In an acid medium, chromium(VI) oxidizes I(-) to produce I(2), I(2) binds excess of I(-) to form I(3)(-), and I(3)(-) can further react with a cationic surfactant (CS) (such as cetyldimethyl benzylammonium chloride (CDBAC), Zephiramine (Zeph), cetylpyridinium bromide (CPB), tetradecyl pyridinium bromide (TPB) and cetyltrimethylammonium bromide (CTAB)) to form ion-association complexes [CS][I(3)]. This results in a significant enhancement of resonance Rayleigh scattering (RRS) and appearance of new RRS spectra. The RRS spectral characteristics of the ion-association complexes, the influencing factors and the optimum conditions of the reactions have been investigated. The intensities of RRS are directly proportional to the concentration of CS. CS in samples are collected using a treated anion exchange column and subsequently complexed by I(3)(-); then the RRS intensities of CS complex are determined at 495 nm. The reactions have high sensitivities, and their detection limits are 7.05 - 9.62 ng/mL for different CS. The effects of foreign substances are investigated and the results show that the method has good selectivity. PMID:16770060

  17. Measurement of the thermal diffusivity of liquids by the forced Rayleigh scattering method: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Nagasaka, Y.; Hatakeyama, T.; Okuda, M.; Nagashima, A.

    1988-07-01

    This article is devoted to the theory and experiment of the forced Rayleigh scattering method for measurement of thermal diffusivity of liquids which can be employed in the form of an instrument operated optically in a contact-free manner. The theoretical considerations included are: (1) effect of cell wall, (2) effect of dye, (3) effect of Gaussian beam intensity distribution, (4) effect of heating duration time, and (5) effect of coupled dye and wall for a heavily absorbing sample. The errors caused by inadequate setting of optical conditions are also analyzed: (1) effects of grating thickness and (2) effects of initial temperature amplitude. Experimental verifications of the theory have been carried out through the measurements on toluene and water as standard reference substances. As a result of these experiments and theory, the criteria for optimum measuring conditions became available. To demonstrate the applicability of the present theory and the apparatus, the thermal diffusivities of toluene and methanol have been measured near room temperature under atmospheric pressure. The accuracy of the present measurement is estimated to be ±3%.

  18. Coupling of a single diamond nanocrystal to a whispering-gallery microcavity: Photon transport benefitting from Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Liu, Yong-Chun; Xiao, Yun-Feng; Li, Bei-Bei; Jiang, Xue-Feng; Li, Yan; Gong, Qihuang

    2011-07-01

    We study the Rayleigh scattering induced by a diamond nanocrystal in a whispering-gallery-microcavity-waveguide coupling system and find that it plays a significant role in the photon transportation. On the one hand, this study provides insight into future solid-state cavity quantum electrodynamics aimed at understanding strong-coupling physics. On the other hand, benefitting from this Rayleigh scattering, effects such as dipole-induced transparency and strong photon antibunching can occur simultaneously. As a potential application, this system can function as a high-efficiency photon turnstile. In contrast to B. Dayan [ScienceSCIEAS0036-807510.1126/science.1152261 319, 1062 (2008)], the photon turnstiles proposed here are almost immune to the nanocrystal’s azimuthal position.

  19. Coupling of a single diamond nanocrystal to a whispering-gallery microcavity: Photon transport benefitting from Rayleigh scattering

    SciTech Connect

    Liu Yongchun; Xiao Yunfeng; Li Beibei; Jiang Xuefeng; Li Yan; Gong Qihuang

    2011-07-15

    We study the Rayleigh scattering induced by a diamond nanocrystal in a whispering-gallery-microcavity-waveguide coupling system and find that it plays a significant role in the photon transportation. On the one hand, this study provides insight into future solid-state cavity quantum electrodynamics aimed at understanding strong-coupling physics. On the other hand, benefitting from this Rayleigh scattering, effects such as dipole-induced transparency and strong photon antibunching can occur simultaneously. As a potential application, this system can function as a high-efficiency photon turnstile. In contrast to B. Dayan et al. [Science 319, 1062 (2008)], the photon turnstiles proposed here are almost immune to the nanocrystal's azimuthal position.

  20. Rayleigh light scattering detection of three α1-adrenoceptor antagonists coupled with high performance liquid chromatograph

    NASA Astrophysics Data System (ADS)

    Li, Ai Ping; Peng, Huanjun; Peng, Jing Dong; Zhou, Ming Qiong; Zhang, Jing

    2015-08-01

    Herein, a Rayleigh light-scattering (RLS) detection method combined with high performance liquid chromatograph (HPLC) without any post-column probe was developed for the separation and determination of three α1-adrenoceptor antagonists. The quantitative analysis is benefiting from RLS signal enhancement upon addition of methanol which induced molecular aggregation to form an hydrophobic interface between aggregates and water that produce a sort of superficial enhanced scattering effect. A good chromatographic separation among the compounds was achieved using a Gemini 5u C18 reversed phase column (250 mm × 4.6 mm; 4 μm) with a mobile phase consisting of methanol and ammonium acetate-formic acid buffer solution (25 mM; pH = 3.0) at the flow rate of 0.7 mL min-1. The RLS signal was monitored at λex = λem = 354 nm. A limit of detection (LOD) of 0.065-0.70 μg L-1 was reached and a linear range was found between peak height and concentration in the range of 0.75-15 μg L-1 for doxazosin mesylate (DOX), 0.075-3.0 μg L-1 for prazosin hydrochloride (PRH), and 0.25-5 μg L-1 for terazosin hydrochloride (TEH), with linear regression coefficients all above 0.999. Recoveries from spiked urine samples were 88.4-99.0% which is within acceptable limits. The proposed method is convenient, reliable and sensitive which has been used successfully in human urine samples.

  1. Rayleigh Scattering Diagnostic Used to Measure Velocity and Density Fluctuation Spectra

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Panda, Jayanta; Elam, Kristie A.

    2003-01-01

    A new, molecular Rayleigh-scattering-based flow diagnostic developed at the NASA Glenn Research Center has been used for the first time to measure the power spectrum of both gas density and radial velocity components in the plumes of high-speed jets. The objective of the work is to develop an unseeded, nonintrusive dynamic measurement technique for studying turbulent flows in NASA test facilities. This technique provides aerothermodynamic data not previously obtainable. It is particularly important for supersonic flows, where hot wire and pitot probes are difficult to use and disturb the flow under study. The effort is part of the nonintrusive instrumentation development program supporting propulsion research at the NASA Glenn Research Center. In particular, this work is measuring fluctuations in flow velocity, density, and temperature for jet noise studies. These data are valuable to researchers studying the correlation of flow fluctuations with far-field noise. One of the main objectives in jet noise research is to identify noise sources in the jet and to determine their contribution to noise generation. The technique is based on analyzing light scattered from molecules within the jet using a Fabry-Perot interferometer operating in a static imaging mode. The PC-based data acquisition system can simultaneously sample velocity and density data at rates to about 100 kHz and can handle up to 10 million data records. We used this system to interrogate three different jet nozzle designs in a Glenn free-jet facility. Each nozzle had a 25.4-mm exit diameter. One was convergent, used for subsonic flow measurements and to produce a screeching underexpanded jet with a fully expanded Mach number of 1.42. The other nozzles (Mach 1.4 and 1.8) were convergent-divergent types. The radial component of velocity and gas density were simultaneously measured in this work.

  2. Half space albedo problem for the nonconservative vector equation of transfer with a combination of Rayleigh and isotropic scattering

    NASA Astrophysics Data System (ADS)

    Şenyiğit, M.

    2016-09-01

    The half-space albedo problem has been solved for a combination of Rayleigh and isotropic scattering using HN method which is developed for the neutron transport studies. The numerical results are compared with exact values obtained using variational method and Chandrasekhar's equation for the {H}-matrix. The analytical solutions of HN method are easy to handle in comparison with the other methods. The numerical results are in good agreement with previous works in literature.

  3. High performance liquid chromatography coupled with resonance Rayleigh scattering for the detection of three fluoroquinolones and mechanism study.

    PubMed

    Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping

    2015-02-01

    A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex=λem=330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N=3) of 0.05-0.12 μg mL(-1) was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.

  4. A novel method for the determination of fast green in grape wine based on resonance Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Li, Qin; Tan, Xuanping; Zheng, Xiaobo; Tang, Weiwei; Yang, Jidong

    2015-11-01

    A novel resonance Rayleigh scattering method was developed for the determination of fast green (FCF) in grape wine. In pH 2.5 Britton Robinson (BR) buffer solution, the scattering signal of acridine orange (AO) was remarkably enhanced after adding trace amount of FCF and forming an ion-association complex, which not only resulted in the change of absorption spectrum, fluorescence spectra, but also led to a significant enhancement of resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS), and second order scattering (SOS). The linear ranges and detection limits for RRS, SOS and FDS were 2-45 × 10-6 mol L-1, 2-24 × 10-6 mol L-1, 2-20 × 10-6 mol L-1, and 8.0 × 10-8 mol L-1, 4.7 × 10-7 mol L-3, 1.0 × 10-7 mol L-3, respectively. In this work, the optimum conditions, the influencing factors and the effects of coexisting substances on the reaction were investigated. The method can be applied to the determination of FCF in grape wine and the results were satisfactory.

  5. Scalar gradient trajectory measurements using high-frequency cinematographic planar Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Gampert, Markus; Narayanaswamy, Venkat; Peters, Norbert

    2013-12-01

    In this work, we perform an experimental investigation into statistics based on scalar gradient trajectories in a turbulent jet flow, which have been suggested as an alternative means to analyze turbulent flow fields by Wang and Peters (J Fluid Mech 554:457-475, 2006, 608:113-138, 2008). Although there are several numerical simulations and theoretical works that investigate the statistics along gradient trajectories, only few experiments in this area have been reported. To this end, high-frequency cinematographic planar Rayleigh scattering imaging is performed at different axial locations of a turbulent propane jet issuing into a CO2 coflow at nozzle-based Reynolds numbers Re 0 = 3,000-8,600. Taylor's hypothesis is invoked to obtain a three-dimensional reconstruction of the scalar field in which then the corresponding scalar gradient trajectories can be computed. These are then used to examine the local structure of the mixture fraction with a focus on the scalar turbulent/non-turbulent interface. The latter is a layer that is located between the fully turbulent part of the jet and the outer flow. Using scalar gradient trajectories, we partition the turbulent scalar field into these three regions according to an approach developed by Mellado et al. (J Fluid Mech 626:333-365, 2009). Based on the latter, we investigate the probability to find the respective regions as a function of the radial distance to the centerline, which turns out to reveal the meandering nature of the scalar T/NT interface layer as well as its impact on the local structure of the turbulent scalar field.

  6. SEARCH FOR RAYLEIGH SCATTERING IN THE ATMOSPHERE OF GJ1214b

    SciTech Connect

    De Mooij, E. J. W.; Jayawardhana, R.; Brogi, M.; Snellen, I. A. G.; Hoekstra, H.; Otten, G. P. P. L.; Bekkers, D. H.; Haffert, S. Y.; Van Houdt, J. J.; De Kok, R. J.; Croll, B.

    2013-07-10

    We investigate the atmosphere of GJ1214b, a transiting super-Earth planet with a low mean density, by measuring its transit depth as a function of wavelength in the blue optical portion of the spectrum. It is thought that this planet is either a mini-Neptune, consisting of a rocky core with a thick, hydrogen-rich atmosphere, or a planet with a composition dominated by water. Most observations favor a water-dominated atmosphere with a small scale-height, however, some observations indicate that GJ1214b could have an extended atmosphere with a cloud layer muting the molecular features. In an atmosphere with a large scale-height, Rayleigh scattering at blue wavelengths is likely to cause a measurable increase in the apparent size of the planet toward the blue. We observed the transit of GJ1214b in the B band with the FOcal Reducing Spectrograph at the Very Large Telescope and in the g band with both ACAM on the William Herschel Telescope (WHT) and the Wide Field Camera at the Isaac Newton Telescope (INT). We find a planet-to-star radius ratio in the B band of 0.1162 {+-} 0.0017, and in the g band 0.1180 {+-} 0.0009 and 0.1174 {+-} 0.0017 for the WHT and INT observations, respectively. These optical data do not show significant deviations from previous measurements at longer wavelengths. In fact, a flat transmission spectrum across all wavelengths best describes the combined observations. When atmospheric models are considered, a small scale-height water-dominated model fits the data best.

  7. Pushing the upper limit of Rayleigh-scatter Temperatures Retrievals into the Lower Thermosphere Using an Inversion Approach

    NASA Astrophysics Data System (ADS)

    Bandoro, J.; Sica, R. J.; Argall, S.

    2012-12-01

    An important aspect of solar terrestrial relations is the coupling between the lower and upper atmosphere-ionosphere system. The coupling is evident in the general circulation of the atmosphere, where waves generate in the lower atmosphere play an important role in the dynamics of the upper atmosphere, which feeds back on the lower atmosphere's circulation. To address coupling problems requires measurements over the broadest range of heights possible. A recently developed retrieval method for temperature profiles from Rayleigh-scatter lidar measurements using an inversion approach allows the upward extension of the altitude range of temperature by 10 to 15 km over the conventional method, thus producing the equivalent of increasing the systems power-aperture product by 4 times [1]. The method requires no changes to the lidar's hardware and thus, can be applied to the body of existing measurements. In addition, since the uncertainties of the retrieved temperature profile are found by a Monte Carlo error analysis, it is possible to isolate systematic and random uncertainties to model the effect of each one on the final uncertainty product for the temperature profile. This unambiguous separation of uncertainties was not previously possible as only the propagation of the statistical uncertainties are typically reported. For the Purple Crow Lidar, corrections for saturation (e.g. non-linearity) in the photocount returns, ozone extinction and background removal all contribute to the overall systematic uncertainty. Results of individually varying each systematic correction and the effect on the final temperature uncertainty through Monte Carlo realizations are presented to determine the importance for each one. For example, it was found that treatment of the background correction as a systematic versus statistical uncertainty gave results in agreement with each other. This new method is then applied to measurements obtained by the Purple Crow lidar' Rayleigh-scatter

  8. Geometry and quadratic nonlinearity of charge transfer complexes in solution using depolarized hyper-Rayleigh scattering.

    PubMed

    Pandey, Ravindra; Ghosh, Sampa; Mukhopadhyay, S; Ramasesha, S; Das, Puspendu K

    2011-01-28

    We report large quadratic nonlinearity in a series of 1:1 molecular complexes between methyl substituted benzene donors and quinone acceptors in solution. The first hyperpolarizability, β(HRS), which is very small for the individual components, becomes large by intermolecular charge transfer (CT) interaction between the donor and the acceptor in the complex. In addition, we have investigated the geometry of these CT complexes in solution using polarization resolved hyper-Rayleigh scattering (HRS). Using linearly (electric field vector along X direction) and circularly polarized incident light, respectively, we have measured two macroscopic depolarization ratios D=I(2ω,X,X)/I(2ω,Z,X) and D(')=I(2ω,X,C)/I(2ω,Z,C) in the laboratory fixed XYZ frame by detecting the second harmonic scattered light in a polarization resolved fashion. The experimentally obtained first hyperpolarizability, β(HRS), and the value of macroscopic depolarization ratios, D and D('), are then matched with the theoretically deduced values from single and double configuration interaction calculations performed using the Zerner's intermediate neglect of differential overlap self-consistent reaction field technique. In solution, since several geometries are possible, we have carried out calculations by rotating the acceptor moiety around three different axes keeping the donor molecule fixed at an optimized geometry. These rotations give us the theoretical β(HRS), D and D(') values as a function of the geometry of the complex. The calculated β(HRS), D, and D(') values that closely match with the experimental values, give the dominant equilibrium geometry in solution. All the CT complexes between methyl benzenes and chloranil or 1,2-dichloro-4,5-dicyano-p-benzoquinone investigated here are found to have a slipped parallel stacking of the donors and the acceptors. Furthermore, the geometries are staggered and in some pairs, a twist angle as high as 30° is observed. Thus, we have demonstrated in

  9. Improvement in Suppression of Pulsed Nd:YAG Laser Light With Iodine Absorption Cells for Filtered Rayleigh Scattering Measurements

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.; Buggele, Alvin E

    1997-01-01

    Filtered Rayleigh scattering using iodine absorption cells is an effective technique for obtaining density, temperature, and velocity measurements in high speed confined flows. By tuning a single frequency laser to a strong iodine absorption line, stray scattered laser light can be greatly suppressed. For example, the minimum transmission predicted by an iodine absorption model calculation is less than 10(exp -5) at the 18788.44/cm line using a 200 mm absorption cell containing iodine vapor at 0.46 T. Measurements obtained by other researches using a CW Nd:YAG laser agree with the model calculations. However, measurements made by us and by others using Q-switched, injection-seeded, frequency doubled Nd:YAG lasers only show minimum transmission of about 3 x 10(exp -3). This greatly reduces the applicability of the filtered Rayleigh scattering technique using these lasers in experiments having large amounts of stray scattered laser light. The purposes of the present study are to characterize the spectrum of the excess light transmitted by the iodine cell and to make changes to the laser to reduce the transmitted laser light. Transmission data as a function of laser frequency for the iodine absorption line at 18788.44/cm are presented. A planar mirror Fabry-Perot interferometer was used to characterize the frequency spectrum of the light passed through the cell. Measurements taken with the laser tuned to the center of the iodine absorption line show the light transmitted through the iodine cell to have a component with a bandwidth of about 40 GHz. This is probably caused by other modes in the laser that exist in spite of the single frequency injection beam. A second broadband component was also observed, possibly caused by the laser flash lamps or by fluorescence. An intracavity etalon was installed in the laser oscillator cavity to suppress the 40 GHz component. Measurements taken with the etalon tuned to the injection frequency showed a reduction in the transmitted

  10. [Determination of Trace Boron Based on Gold Nanorod Plasmonic Resonance Rayleigh Scattering Energy Transfer to the Coordinate].

    PubMed

    Ye, Ling-ling; Li, Ting-sheng; Luo, Yang-he; Wen, Gui-qing; Liang, Ai-hui; Jiang, Zhi-liang

    2015-05-01

    B is a necessary trace element for human and animals, but the excess intake of B caused poison. Thus, it is very important to determination of B in foods and water. The target of this study is development of a new, sensitive and selective resonance Rayleigh scattering energy transfer (RRS-ET) for the determination of B. The combination of energy transfer with resonance Rayleigh scattering (RRS) has developed a new technology called RRS-ET, which can realize selective and sensitive detection of boric acid. The gold nanorods in diameter of 12 nm and length of 37 nm were prepared by the seed growth procedure. In pH 5. 6 NH4 Ac-HAc buffer solution and in the presence of azomethine-H (AMH), the gold nanorod particles exhibited a strong resonance Rayleigh scattering (RRS) peak at 404 nm. In the presence of boric acid, it reacts with AMH to form AMH-boric acid (AMH-B) complexes. When the complexe as a receptor close to the gold nanorod as a donor, the resonance Rayleigh scattering energy transfer (RRS-ET) take placed that resulted in the Rayleigh scattering signal quenching. With the increase of the concentration of boric acid, the formed complexes increased, the scattering light energy of gold nanorod transfer to the complexes increased, resulting in the Rayleigh scattering intensity linearly reduced at 404 nrn. The decreased RRS intensity responds linearly to the concentration of boron over 10~750 ng . mL-1 B, with a regress equation of ΔI404 nm =3. 53c+24 and a detection of 5 ng mL-1 B. The influence of coexistence substances on the RRS-ET determination of 2. 3 X 10(-7) mol . L-1 B was considered in details. Results showed that this new RRS-ET method is of high selectivity, that is, 4 X 10(-4) mol . L-1 Mn2+, Cd2+, Zn2+, Bi+, Na+, Al3+, glucose, Hg2+, IO3-, F-, SO(2-)3, SiO3-, NO3-, CIO4-, H2O2, mannitol, glycerol, and ethylene glycol, 4X 10(-5) mol . L-1 L-tyrosine, and 2 X 10(-4) mol . L-1 L-glutamic acid do not interfere with the determination. Based on this, a new

  11. [DNAzyme cracking-nanogold resonance Rayleigh scattering spectral method for the determination of trace Cu2+].

    PubMed

    Wang, Sheng-Mian; Wu, Meng; Liang, Ai-Hui; Jiang, Zhi-Liang

    2013-01-01

    In the condition of pH 7.0 HEPES buffer solution and 0.19 mol x L(-1) NaCl, the substrate strand DNA (SS) and the enzyme strand DNA (ES) hybridized into a double-stranded DNA (dsDNA) at 80 degrees C. The substrate chain of dsDNA could be cracked by Cu2+, and the released single-stranded DNA (ssDNA) were adsorbed on the nanogold(NG) surface to produce a stable NGssDNA conjugate. The unprotected NG was aggregated to form NG aggregation (NGA) that exhibited a resonance Rayleigh scattering (RRS) peak at 627 nm. When the Cu2+ was added, the NGssDNA increased, and the NGA decreased that caused the RRS intensity decreasing at 627 nm, and the solution color changed from blue to red. The decreased RS intensity deltaI was linear with the Cu2+ was added, the NGssDNA increased, and the NGA decreased that caused the RRS intensity decreasing at 627 nm, the solution color changed from blue to red. The decreased RS intensity deltaI was linear to the Cu2+ concentration in the range of 15-1 250 nmol x L(-1), with a regression equation of deltaI = 0.17c-2.3, coefficient of 0.989 5 and a detection limit of 8 nmol x L(-1) Cu2+. In addition, the influence of foreign substances on the determination of 0.75 micromol x L(-1) Cu2+ was considered. The results show that 3 micro mol x L(-1) Ca2+, Pb2+ and Hg2+, 2 micromol x L(-1) Fe2+, 1 micromol x L(-1) Sn2+, 4 micromol x L(-1) Al3+, 12 micromol x L(-1) Mn2+, 4 micromol x L(-1) Co2+ and Ni2+ did not interfered with the determination. This indicates that this method has good selectivity. This new, rapid, sensitive, selective RRS method was applied to the determination of Cu2+ in water, with satisfactory results.

  12. Study on the interaction between fluoroquinolones and erythrosine by absorption, fluorescence and resonance Rayleigh scattering spectra and their application

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Liu, Zhongfang; Liu, Jiangtao; Liu, Shaopu; Shen, Wei

    2008-03-01

    In pH 4.4-4.5 Britton-Robinson (BR) buffer solution, fluoroquinolone antibiotics (FLQs) including ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV) and lomefloxacin (LOM) could react with erythrosine (Ery) to form 1:1 ion-association complexes, which not only resulted in the changes of the absorption spectra and the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS). These offered some indications of the determination of fluoroquinolone antibiotics by spectrophotometric, fluorescence and resonance Rayleigh scattering methods. The detection limits for fluoroquinolone antibiotics were in the range of 0.097-0.265 μg/mL for absorption methods, 0.022-0.100 μg/mL for fluorophotometry and 0.014-0.027 μg/mL for RRS method, respectively. Among them, the RRS method had the highest sensitivity. In this work, the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions and the properties of the analytical chemistry were investigated. The methods have been successfully applied to determination of some fluoroquinolone antibiotics in human urine samples and tablets. Taking CIP-Ery system as an example, the charge distribution, the enthalpy of formation and the mean polarizability were calculated by density function theory (DFT) method. In addition, the reasons for the enhancement of scattering spectra were discussed.

  13. Time-Average Molecular Rayleigh Scattering Technique for Measurement of Velocity, Denisty, Temperature, and Turbulence Intensity in High Speed Nozzle Flows

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Seasholtz, Richard G.; Elam, Kristie A.; Panda, Jayanta

    2004-01-01

    A molecular Rayleigh scattering based flow diagnostic is developed to measure time average velocity, density, temperature, and turbulence intensity in a 25.4-mm diameter nozzle free jet facility. The spectrum of the Rayleigh scattered light is analyzed using a Fabry-Perot interferometer operated in the static imaging mode. The resulting fringe pattern containing spectral information of the scattered light is recorded using a low noise CCD camera. Nonlinear least squares analysis of the fringe pattern using a kinetic theory model of the Rayleigh scattered light provides estimates of density, velocity, temperature, and turbulence intensity of the gas flow. Resulting flow parameter estimates are presented for an axial scan of subsonic flow at Mach 0.95 for comparison with previously acquired pitot tube data, and axial scans of supersonic flow in an underexpanded screeching jet. The issues related to obtaining accurate turbulence intensity measurements using this technique are discussed.

  14. Study of the pair correlations between p-nitroaniline molecules in solution by depolarized hyper-Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Chan, Y. C.; Wong, K. Y.

    2012-05-01

    The concentration dependence of the hyper-Rayleigh scattering depolarization ratios of p-nitroaniline in solution was obtained and the results were compared with theory. It was found that the experimental data can be theoretically accounted for by using a pair distribution function that includes only direct correlation, with the molecules interact through a dipolar hard-sphere potential. The results show that short-range dipole-dipole interactions are responsible for the correlation between pairs of p-nitroaniline molecules in solution.

  15. A dual-wavelength overlapping resonance Rayleigh scattering method for the determination of chondroitin sulfate with nile blue sulfate

    NASA Astrophysics Data System (ADS)

    Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

    2011-12-01

    A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).

  16. Noise induced in optical fibers by double Rayleigh scattering of a laser with a 1/fν frequency noise.

    PubMed

    Fleyer, Michael; Heerschap, Seth; Cranch, Geoffrey A; Horowitz, Moshe

    2016-03-15

    We study, theoretically and experimentally, intensity noise induced by double Rayleigh scattering in long optical fibers. The results of the theoretical model are compared to experimental results performed with a high-coherence-length laser with a frequency noise spectrum that is dominated by 1/fν noise. Excellent quantitative agreement between theoretical and experimental RF spectra were obtained for frequencies as low as 10 Hz and for fiber lengths between 4 and 45 km. Strong low-frequency intensity noise that is induced by 1/fν frequency noise of the laser may limit the performance of interferometric fiber optic sensors that require high-coherence-length lasers. The intensity noise due to double Rayleigh backscattering can be suppressed by reducing the coherence length of the laser. Therefore, the intensity noise has a complex and non-monotonic dependence on the 1/fν frequency noise amplitude of the laser. Stimulated Brillouin scattering will add a significant noise for input powers greater than about 7 mW for a 30 km length fiber.

  17. New technique for retrieval of atmospheric temperature profiles from Rayleigh-scatter lidar measurements using nonlinear inversion.

    PubMed

    Khanna, Jaya; Bandoro, Justin; Sica, R J; McElroy, C Thomas

    2012-11-20

    The conventional method of calculating atmospheric temperature profiles using Rayleigh-scattering lidar measurements has limitations that necessitate abandoning temperatures retrieved at the greatest heights, due to the assumption of a pressure value required to initialize the integration at the highest altitude. An inversion approach is used to develop an alternative way of retrieving nightly atmospheric temperature profiles from the lidar measurements. Measurements obtained by the Purple Crow lidar facility located near The University of Western Ontario are used to develop and test this new technique. Our results show temperatures can be reliably retrieved at all heights where measurements with adequate signal-to-noise ratio exist. A Monte Carlo technique was developed to provide accurate estimates of both the systematic and random uncertainties for the retrieved nightly average temperature profile. An advantage of this new method is the ability to seed the temperature integration from the lowest rather than the greatest height, where the variability of the pressure is smaller than in the mesosphere or lower thermosphere and may in practice be routinely measured by a radiosonde, rather than requiring a rocket or satellite-borne measurement. Thus, this new technique extends the altitude range of existing Rayleigh-scatter lidars 10-15 km, producing the equivalent of four times the power-aperture product.

  18. Applicability of the Rayleigh-Gans approximation for scattering by snowflakes at microwave frequencies in vertical incidence

    NASA Astrophysics Data System (ADS)

    Tyynelä, J.; Leinonen, J.; Westbrook, C. D.; Moisseev, D.; Nousiainen, T.

    2013-02-01

    Abstract The applicability of the <span class="hlt">Rayleigh</span>-Gans approximation (RGA) for <span class="hlt">scattering</span> by snowflakes is studied in the microwave region of the electromagnetic spectrum. Both the shapes of the single ice crystals, or monomers, and their amounts in the modeled snowflakes are varied. For reference, the discrete-dipole approximation (DDA) is used to produce numerically accurate solutions to the single-<span class="hlt">scattering</span> properties, such as the backscattering and extinction cross-sections, single-<span class="hlt">scattering</span> albedo, and the asymmetry parameter. We find that the single-<span class="hlt">scattering</span> albedo is the most accurate with only about 10% relative bias at maximum. The asymmetry parameter has about 0.12 absolute bias at maximum. The backscattering and extinction cross-sections show about - 65% relative biases at maximum, corresponding to about - 4.6 dB difference. Overall, the RGA agrees well with the DDA computations for all the cases studied and is more accurate for the integrated quantities, such as the single-<span class="hlt">scattering</span> albedo and the asymmetry parameter than the cross-sections for the same snowflakes. The accuracy of the RGA seems to improve, when the number of monomers is increased in an aggregate, and decrease, when the frequency increases. It is also more accurate for less dense monomer shapes, such as stellar dendrites. The DDA and RGA results are well correlated; the sample correlation coefficients of those are close to unity throughout the study. Therefore, the accuracy of the RGA could be improved by applying appropriate correction factors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21163688','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21163688"><span id="translatedtitle">Study on the ternary mixed ligand complex of palladium(II)-aminophylline-fluorescein sodium by resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, second-order <span class="hlt">scattering</span> and frequency doubling <span class="hlt">scattering</span> spectrum and its analytical application.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Peili; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli</p> <p>2011-01-01</p> <p>The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, second-order <span class="hlt">scattering</span> and frequency doubling <span class="hlt">scattering</span> spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS), second-order <span class="hlt">scattering</span> (SOS) and frequency doubling <span class="hlt">scattering</span> spectrum (FDS) were enhanced. The maximum <span class="hlt">scattering</span> wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The <span class="hlt">scattering</span> intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive <span class="hlt">scattering</span> methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. PMID:21163688</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AcSpA..74...36L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AcSpA..74...36L"><span id="translatedtitle">Resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and resonance non-linear <span class="hlt">scattering</span> method for the determination of aminoglycoside antibiotics with water solubility CdS quantum dots as probe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Zhengwen; Liu, Shaopu; Wang, Lei; Peng, Juanjuan; He, Youqiu</p> <p>2009-09-01</p> <p>In pH 6.6 Britton-Robinson buffer medium, the CdS quantum dots capped by thioglycolic acid could react with aminoglycoside (AGs) antibiotics such as neomycin sulfate (NEO) and streptomycin sulfate (STP) to form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which resulted in a great enhancement of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) and resonance non-linear <span class="hlt">scattering</span> such as second-order <span class="hlt">scattering</span> (SOS) and frequency doubling <span class="hlt">scattering</span> (FDS). The maximum <span class="hlt">scattering</span> peak was located at 310 nm for RRS, 568 nm for SOS and 390 nm for FDS, respectively. The enhancements of <span class="hlt">scattering</span> intensity (Δ I) were directly proportional to the concentration of AGs in a certain ranges. A new method for the determination of trace NEO and STP using CdS quantum dots probe was developed. The detection limits (3 σ) were 1.7 ng mL -1 (NEO) and 4.4 ng mL -1 (STP) by RRS method, were 5.2 ng mL -1 (NEO) and 20.9 ng mL -1 (STP) by SOS method and were 4.4 ng mL -1 (NEO) and 25.7 ng mL -1 (STP) by FDS method, respectively. The sensitivity of RRS method was the highest. The optimum conditions and influence factors were investigated. In addition, the reaction mechanism was discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995ApOpt..34.7410S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995ApOpt..34.7410S"><span id="translatedtitle">Mie and <span class="hlt">Rayleigh</span> modeling of visible-light <span class="hlt">scattering</span> in neonatal skin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saidi, Iyad S.; Jacques, Steven L.; Tittel, Frank K.</p> <p>1995-11-01</p> <p>Reduced-<span class="hlt">scattering</span> coefficients of neonatal skin were deduced in the 450-750-nm range from integrating-sphere measurements of the total reflection and total transmission of 22 skin samples. The reduced-<span class="hlt">scattering</span> coefficients increased linearly at each wavelength with gestational maturity. The distribution of diameters d and concentration rho A of the skin-sample collagen fibers were measured in histological sections of nine neonatal skin samples of varying gestational ages. An algorithm that calculates Mie <span class="hlt">scattering</span> by cylinders was used to model the <span class="hlt">scattering</span> by the collagen fibers in the skin. The fraction of the reduced-<span class="hlt">scattering</span> coefficient mu s` that was attributable to Mie <span class="hlt">scattering</span> by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcSpA.162...93Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcSpA.162...93Y"><span id="translatedtitle">The fluorescence and resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> spectral study and analytical application of cerium (IV) and cefoperazone system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Yusheng; Fu, Shenghui; Xu, Qianying; Yang, Jidong; Hu, Xiaoli; Liu, Shaopu</p> <p>2016-06-01</p> <p>In weak acidic medium of pH 3.5-5.6, Ce(IV) can be reduced by cefoperazone (CPZ) to be Ce(III), which further combined with CPZ to form complex Ce(OH)3CPZ. This complex not only has higher fluorescence than Ce(III), but also results in significant increase of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS), second order <span class="hlt">scattering</span> (SOS) and frequency doubling <span class="hlt">scattering</span> (FDS). The wavelengths of maximum fluorescence exciting and emission are located at 356 nm/349 nm, while the maximum wavelengths of RRS, SOS and FDS are at 312 nm, 550 nm and 390 nm, respectively. The intensity of fluorescence and <span class="hlt">scattering</span> are all linear with the concentration of CPZ in certain conditions. The detection limit of most sensitive RRS method for CPZ is 2.1 ng mL- 1. The optimum conditions for detecting CPZ using RRS method are investigated. The effect of co-existing substances shows that the method has excellent selectivity, especially since other cephalosporins don't have similar reactions. Therefore, it can be achieved to determine CPZ in cephalosporins selectively. The paper also focuses on the reaction mechanism, the consistent and contracture of the resultant. The reasons for enhanced intensity are presumed in the meantime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15765711','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15765711"><span id="translatedtitle">Ultraviolet <span class="hlt">Rayleigh</span>-Mie lidar with Mie-<span class="hlt">scattering</span> correction by Fabry-Perot etalons for temperature profiling of the troposphere.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao</p> <p>2005-03-01</p> <p>A <span class="hlt">Rayleigh-Mie-scattering</span> lidar system at an eye-safe 355-nm ultraviolet wavelength that is based on a high-spectral-resolution lidar technique is demonstrated for measuring the vertical temperature profile of the troposphere. Two <span class="hlt">Rayleigh</span> signals, which determine the atmospheric temperature, are filtered with two Fabry-Perot etalon filters. The filters are located on the same side of the wings of the <span class="hlt">Rayleigh-scattering</span> spectrum and are optically constructed with a dual-pass optical layout. This configuration achieves a high rejection rate for Mie <span class="hlt">scattering</span> and reasonable transmission for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. The Mie signal is detected with a third Fabry-Perot etalon filter, which is centered at the laser frequency. The filter parameters were optimized by numerical calculation; the results showed a Mie rejection of approximately -45 dB, and <span class="hlt">Rayleigh</span> transmittance greater than 1% could be achieved for the two <span class="hlt">Rayleigh</span> channels. A Mie correction method is demonstrated that uses an independent measure of the aerosol <span class="hlt">scattering</span> to correct the temperature measurements that have been influenced by the aerosols and clouds. Simulations and preliminary experiments have demonstrated that the performance of the dual-pass etalon and Mie correction method is highly effective in practical applications. Simulation results have shown that the temperature errors that are due to noise are less than 1 K up to a height of 4 km for daytime measurement for 300 W m(-2) sr(-1) microm(-1) sky brightness with a lidar system that uses 200 mJ of laser energy, a 3.5-min integration time, and a 25-cm telescope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcSpA.140...15T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcSpA.140...15T"><span id="translatedtitle">Study on erythrosine-phen-Cd(II) systems by resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, absorption spectra and their analytical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tian, Jing; Zhang, Qiqi; Liu, Shaopu; Yang, Jidong; Teng, Ping; Zhu, Jinghui; Qiao, Man; Shi, Ying; Duan, Ruilin; Hu, Xiaoli</p> <p>2015-04-01</p> <p>In pH 7.0-8.0 KH2PO4-Na2HPO4 buffer solution, Cd(II) reacted with 1,10-phenanthroline to form chelate cation [Cd(phen)3]2+, which further reacted with anion of erythrosine to form ternary ion-association complex through electrostatic attraction and hydrophobic effect. This process could result in remarkable absorption spectra change and produce obvious fading reaction at 528 nm. Absorbance change (ΔA) of system was directly proportional to the concentration of Cd(II). Hereby, a highly sensitive spectrophotometric method for the determination of Cd(II) was established. The molar absorption coefficient was 2.29 × 105 L mol-1 cm-1 and the detection limit of Cd(II) was 26.5 ng mL-1. Furthermore, the resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) of this system with two peaks located at 371 and 590 nm enhanced significantly, and second-order <span class="hlt">scattering</span> (SOS) and frequence doubling <span class="hlt">scattering</span> (FDS) of this system changed notably at 640 and 350 nm, respectively. Under the optimum conditions, the <span class="hlt">scattering</span> intensities (ΔIRRS, ΔIDWO-RRS, ΔISOS and ΔIFDS) had good linear relationship with the concentration of Cd(II) in certain ranges. The detection limits of Cd(II) were 1.27 ng mL-1, 1.39 ng mL-1, 4.03 ng mL-1, 5.92 ng mL-1 and 14.7 ng mL-1 for dual-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (DWO-RRS), RRS (371 nm), RRS (590 nm), SOS and FDS, respectively. In addition, the suitable reaction conditions and effects of coexisting substances were investigated. The methods had been successfully applied to the determination of Cd(II) in environmental water samples. The recovery range was between 93.0% and 103.0% and the relative standard deviation (RSD) was between 2.5% and 4.3%. The results were in agreement with those obtained from atomic absorption spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcSpA.162...75W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcSpA.162...75W"><span id="translatedtitle">A sensitive and selective resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> method for quick detection of avidin using affinity labeling Au nanoparticles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Qi; Huang, Xi; Fu, Xuan; Deng, Huan; Ma, Meihu; Cai, Zhaoxia</p> <p>2016-06-01</p> <p>Avidin is a glycoprotein with antinutritional property, which should be limited in daily food. We developed an affinity biosensor system based on resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) and using affinity biotin labeling Au nanoparticles (AuNPs). This method was selective and sensitive for quick avidin detection due to the avidin-biotin affinitive interaction. Under optimal conditions, RRS intensity of biotin-AuNPs increase linearly with an increasing concentration of avidin from 5 to 160 ng/mL. The lower limit of detection was 0.59 ng/mL. This rapid and selective avidin detection method was used in synthetic samples and egg products with recoveries of between 102.97 and 107.92%, thereby demonstrating the feasible and practical application of this assay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24723431','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24723431"><span id="translatedtitle">A new and highly sensitive resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> assay for lysozyme using aptamer-nanogold as a probe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Lu; Zhang, Xinghui; Liang, Aihui; Liu, Qingye; Jiang, Zhiliang</p> <p>2014-12-01</p> <p>Gold nanoparticles (GN), 10 nm in size, were modified by using lysozyme aptamer (Apt) to obtain a stable Apt–GN probe in pH 8.05 Tris/HCl buffer solutions containing 0.04 mol/L NaCl. Upon addition of lysozyme (LYS), it reacted with the Apt of the probe to form a very stable Apt–LYS complex and to release GNs, which aggregated to form large clusters with a resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) peak at 368 nm. The enhanced peak intensity, ΔI, was linear to the LYS concentration in the range 0.2–5.2 nmol/L, with a detection limit of 0.05 nmol/L. The influence of foreign substance was tested, and the results showed that this RRS method has high selectivity. This Apt–GN RRS method was applied to the analysis of LYS in a real sample, with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24686652','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24686652"><span id="translatedtitle">Daytime measurements of atmospheric temperature profiles (2-15 km) by lidar utilizing <span class="hlt">Rayleigh</span>-Brillouin <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Witschas, Benjamin; Lemmerz, Christian; Reitebuch, Oliver</p> <p>2014-04-01</p> <p>In this Letter, we report on a novel method for measuring atmospheric temperature profiles by lidar during daytime for heights of 2-15.3 km, with a vertical resolution of 0.3-2.2 km, using <span class="hlt">Rayleigh</span>-Brillouin <span class="hlt">scattering</span>. The measurements are performed by scanning a laser (λ=355 nm) over a 12 GHz range and using a Fabry-Pérot interferometer as discriminator. The temperature is derived by using a new analytical line shape model assuming standard atmospheric pressure conditions. Two exemplary temperature profiles resulting from measurements over 14 and 27 min are shown. A comparison with radiosonde temperature measurements shows reasonable agreement. In cloud-free conditions, the temperature difference reaches up to 5 K within the boundary layer, and is smaller than 2.5 K above. The statistical error of the derived temperatures is between 0.15 and 1.5 K. PMID:24686652</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27561996','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27561996"><span id="translatedtitle">On-Resonance Fluorescence, Resonance <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span>, and Ratiometric Resonance Synchronous Spectroscopy of Molecular- and Quantum Dot-Fluorophores.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siriwardana, Kumudu; Nettles, Charles B; Vithanage, Buddhini C N; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao</p> <p>2016-09-20</p> <p>Existing studies on molecular fluorescence have almost exclusively been focused on Stokes-shifted fluorescence spectroscopy (SSF) in which the emitted photon is detected at the wavelengths longer than that for the excitation photons. Information on fluorophore on-resonance fluorescence (ORF) and resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) is limited and often problematic due to the complex interplay of the fluorophore photon absorption, ORF emission, RRS, and solvent <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. Reported herein is a relatively large-scale systematic study on fluorophore ORF and RRS using the conventional UV-vis extinction and SSF measurements in combination with the recently reported ratiometric resonance synchronous spectroscopic (R2S2, pronounced as "R-Two-S-Two") method. A series of fundamental parameters including fluorophore ORF cross sections and quantum yields have been quantified for the first time for a total of 12 molecular and 6 semiconductor quantum dot (QD) fluorophores. All fluorophore spectra comprise a well-defined Gaussian peak with a full width at half-maximum ranging from 4 to 30 nm. However, the RRS features of fluorophores differ drastically. The effect of fluorophore aggregation on its RRS, UV-vis, R2S2, and SSF spectra was also discussed. This work highlights the critical importance of the combined UV-vis extinction, SSF, and R2S2 spectroscopic measurements for material characterizations. The method and insights described in this work can be directly used for improving the reliability of RRS spectroscopic methods in chemical analysis. In addition, it should pave the way for developing novel R2S2-based analytical applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007OExpr..15.5572G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007OExpr..15.5572G"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Gans <span class="hlt">scattering</span> approximation: surprisingly useful for understanding backscattering from disk-like particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gordon, Howard R.</p> <p>2007-04-01</p> <p>Recent computations of the backscattering cross section of randomly-oriented disk-like particles (refractive index, 1.20) with small-scale internal structure, using the discrete-dipole approximation (DDA), have been repeated using the <span class="hlt">Rayleigh</span>-Gans approximation (RGA). As long as the thickness of the disks is approximately 20% of the wavelength (or less), the RGA agrees reasonably well quantitatively with the DDA. The comparisons show that the RGA is sufficiently accurate to be useful as a quantitative tool for exploring the backscattering features of disk-like particles with complex structure. It is used here to develop a zeroth-order correction for the neglect of birefringence on modeling the backscattering of detached coccoliths from E. huxleyi.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010A%26A...522A..41F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010A%26A...522A..41F"><span id="translatedtitle">Spectral line polarization with angle-dependent partial frequency redistribution. I. A Stokes parameters decomposition for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frisch, H.</p> <p>2010-11-01</p> <p>Context. The linear polarization of a strong resonance lines observed near the solar limb is created by a multiple-<span class="hlt">scattering</span> process. Partial frequency redistribution (PRD) effects must be accounted for to explain the polarization profiles. The redistribution matrix describing the <span class="hlt">scattering</span> process is a sum of terms, each containing a PRD function multiplied by a <span class="hlt">Rayleigh</span> type phase matrix. A standard approximation made in calculating the polarization is to average the PRD functions over all the <span class="hlt">scattering</span> angles, because the numerical work needed to take the angle-dependence of the PRD functions into account is large and not always needed for reasonable evaluations of the polarization. Aims: This paper describes a Stokes parameters decomposition method, that is applicable in plane-parallel cylindrically symmetrical media, which aims at simplifying the numerical work needed to overcome the angle-average approximation. Methods: The decomposition method relies on an azimuthal Fourier expansion of the PRD functions associated to a decomposition of the phase matrices in terms of the Landi Degl'Innocenti irreducible spherical tensors for polarimetry T^K_Q(i, Ω) (i Stokes parameter index, Ω ray direction). The terms that depend on the azimuth of the <span class="hlt">scattering</span> angle are retained in the phase matrices. Results: It is shown that the Stokes parameters I and Q, which have the same cylindrical symmetry as the medium, can be expressed in terms of four cylindrically symmetrical components I_Q^K (K = Q = 0, K = 2, Q = 0, 1, 2). The components with Q = 1, 2 are created by the angular dependence of the PRD functions. They go to zero at disk center, ensuring that Stokes Q also goes to zero. Each component I_Q^K is a solution to a standard radiative transfer equation. The source term S_Q^K are significantly simpler than the source terms corresponding to I and Q. They satisfy a set of integral equations that can be solved by an accelerated lambda iteration (ALI) method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFD.1A011F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFD.1A011F"><span id="translatedtitle">Development of a Burner System and <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span> Method to Measure Soot Concentration for Diesel-Relevant Fuels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fletcher, Sara; Fisher, Brian</p> <p>2013-11-01</p> <p>Soot, a harmful component of particulate matter, is found in high concentrations in diesel exhaust. This work aims to develop a better understanding of the relationship between chemical structure and soot evolution, which is expected to inform methods to reduce or eliminate soot in diesel combustion. Successful aspects of previous experiments have been combined into a new method to characterize soot formation, growth, and oxidation. Soot is quantified via combined <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and extinction, using a pulsed 532-nm Nd:YAG laser and sensitive photodetectors. A methane/oxygen diffusion flame serves as a baseline, then species of interest are doped into the fuel stream in low concentration and the change in soot is quantified relative to the base flame. This perturbation method enables study of soot for different species in a flame that has nominally constant global properties. This study focused on fuel components n-heptane and toluene, which have straight-chain and aromatic molecular structures, respectively. Soot was quantified throughout the flame, and it was found that the soot <span class="hlt">scattering</span> signal was significantly higher for toluene than for n-heptane. Analysis of the signals to quantify actual soot concentrations remains a topic of future work. Funding from NSF REU grant 1062611.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27507443','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27507443"><span id="translatedtitle">Highly sensitive determination of antimony in food by resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>-energy transfer between grapheme oxide and I3(.).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wen, Guiqing; Zhang, Xinghui; Li, Yuan; Luo, Yanghe; Liang, Aihui; Jiang, Zhiliang</p> <p>2017-01-01</p> <p>Sb(III) was reduced to SbH3 gas and introduced to the I3(-)-grapheme oxide (GO) or I3(-)-silver nanorod (AgNR)-Victoria blue B (VBB) solutions. Resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> energy transfer (RRS-ET) occurred between the donor GO and the acceptor I3(-) due to the overlap between the absorption peak of I3(-) and RRS peak of GO. When I3(-) was reduced by SbH3, RRS-ET weakened and the RRS intensity enhanced. The increased RRS intensity was linear to Sb concentration in the range of 2.1-376.6μg/L. In the I3(-)-AgNR-VBB solution, I3(-) combined with VBB to form VBB-I3 and there was a weak surface-enhanced Raman <span class="hlt">scattering</span> (SERS) effect. When SbH3 reduced I3(-), the SERS intensity increased due to the release of SERS active VBB. The enhanced SERS intensity was linear for Sb concentration in the range of 8.4-292.9μg/L. The RRS-ET method was applied for determination of Sb in food with satisfactory results. PMID:27507443</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcSpA.161...19T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcSpA.161...19T"><span id="translatedtitle">Double-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> technique for the simultaneous quantitative analysis of three β-adrenergic blockade</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tan, Xuanping; Yang, Jidong; Li, Qin; Yang, Qiong; Shen, Yizhong</p> <p>2016-05-01</p> <p>Four simple and accurate spectrophotometric methods were proposed for the simultaneous determination of three β-adrenergic blockade, e.g. atenolol, metoprolol and propranolol. The methods were based on the reaction of the three drugs with erythrosine B (EB) in a Britton-Robinson buffer solution at pH 4.6. EB could combine with the drugs to form three ion-association complexes, which resulted in the resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) intensity that is enhanced significantly with new RRS peaks that appeared at 337 nm and 370 nm, respectively. In addition, the fluorescence intensity of EB was also quenched. The enhanced <span class="hlt">scattering</span> intensities of the two peaks and the fluorescence quenched intensity of EB were proportional to the concentrations of the drugs, respectively. What is more, the RRS intensity overlapped with the double-wavelength of 337 nm and 370 nm (so short for DW-RRS) was also proportional to the drugs concentrations. So, a new method with highly sensitive for simultaneous determination of three bisoprolol drugs was established. Finally, the optimum reaction conditions, influencing factors and spectral enhanced mechanism were investigated. The new DW-RRS method has been applied to simultaneously detect the three β-blockers in fresh serum with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992JaJAP..31..329H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992JaJAP..31..329H"><span id="translatedtitle">Cell Thickness Effects in the Determination of Elastic Constant Ratios by Observing <span class="hlt">Rayleigh</span> Light <span class="hlt">Scattered</span> Intensity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hall, Richard; Miyachi, Kouichi; Newton, David; Takezoe, Hideo; Fukuda, Atsuo</p> <p>1992-02-01</p> <p>The effects of the finite <span class="hlt">scattering</span> volume on the values of elastic constant ratios determined have been studied by computer simulation. The errors in the simulated values of K1/K2 and K3/K2 are dependent on the position of the starting angle of the scan. The error is greatest for thinner cells (≈7 μm) and in the angular regions where the geometrical factor Gm introduced by de Gennes, or a component of the <span class="hlt">scattering</span> vector q becomes zero, i.e. for external <span class="hlt">scattering</span> angles approximately less than 10° and those between approximately 20° and 60°, depending on the <span class="hlt">scattering</span> geometry used. The approximation introduced by van der Meulen and Zijlstra in defining the orthogonal base system (\\hat{\\mbi{e}}1, \\hat{\\mbi{e}}2, \\hat{\\mbi{e}}3) has also been discussed; it is inappropriate in thin cells to use the <span class="hlt">scattering</span> vector q instead of the wave vector \\mbi{k}l of the director fluctuations when determining K1/K2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22051291','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22051291"><span id="translatedtitle">Collision-induced hyper-<span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> in gaseous dihydrogen-neon mixtures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Glaz, W.; Bancewicz, T.; Godet, J.-L.; Haskopoulos, A.; Maroulis, G.</p> <p>2011-07-15</p> <p>Cartesian components of the collision-induced (CI) hyperpolarizability {Delta}{beta} tensor are computed for the linear, T-shaped, and 45 deg. configurations of the H{sub 2}-Ne pair in the intermolecular range 3 to 14 bohr. Symmetry-adapted components {Delta}{beta}{sub {lambda}L}{sup (K)}(R) of the vector (K=1) part, as well as the septor (K=3) part, of the H{sub 2}-Ne CI hyperpolarizability are calculated starting from the ab initio Cartesian hyperpolarizability tensor values transformed into their spherical counterparts. By applying these quantities, the vector together with the septor collision-induced hyper-<span class="hlt">Rayleigh</span> (CIHR) spectra for the H{sub 2}-Ne binary gas mixture are determined in the frequency range from -1250 to 2500 cm{sup -1}. The profiles are partially employed as a benchmarking device to estimate the importance of the short intermolecular distance part of the {Delta}{beta}(R) dependence. The depolarization ratio of the CIHR spectra in the whole frequency range is also calculated. The nature of the CIHR signal and the feasibility of the related experiments are discussed and analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JOpt...18g5007A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JOpt...18g5007A"><span id="translatedtitle">Numerical investigation of the <span class="hlt">Rayleigh</span> hypothesis for electromagnetic <span class="hlt">scattering</span> by a particle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Auguié, Baptiste; Somerville, Walter R. C.; Roache, Stanley; Le Ru, Eric C.</p> <p>2016-07-01</p> <p>The validity of the <span class="hlt">Rayleigh</span> hypothesis (RH) has been a long-standing issue in the applicability of the T-matrix method to near-field calculations, and despite numerous theoretical works, the practical consequences for numerical simulations have remained unclear. Such calculations are increasingly important in the field of nano-optics, for which accurate and efficient modeling tools are in high demand. We here tackle this challenge by investigating numerically the convergence behavior of series expansions of the electric field around spheroidal particles, which provides us with unambiguous examples to clarify the conditions of convergence. This study is made possible by the combination of alternative methods to compute near-fields accurately, and crucially, the recent improvements in the calculation of T-matrix elements free from numerical instabilities, as such errors would otherwise obfuscate the intrinsic convergence properties of the field series. The resulting numerical confirmation for the range of validity of the RH, complemented by a better understanding of the convergence behavior of the field expansions, is a crucial step toward future developments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6186219','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6186219"><span id="translatedtitle">Dense medium radiative transfer theory for two <span class="hlt">scattering</span> layers with a <span class="hlt">Rayleigh</span> distribution of particle sizes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>West, R.; Tsang, Leung; Winebrenner, D.P. )</p> <p>1993-03-01</p> <p>Dense medium radiative transfer theory is applied to a three-layer model consisting of two <span class="hlt">scattering</span> layers overlying a homogeneous half space with a size distribution of particles in each layer. A model with a distribution of sizes gives quite different results than those obtained from a model with a single size. The size distribution is especially important in the low frequency limit when <span class="hlt">scattering</span> is strongly dependent on particle size. The size distribution and absorption characteristics also affect the extinction behavior as a function of fractional volume. Theoretical results are also compared with experimental data. The sizes, permittivities, and densities used in the numerical illustrations are typical values for snow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JQSRT.178...66R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JQSRT.178...66R"><span id="translatedtitle">Violation of a Bell-like inequality by a combination of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> with a Mach-Zehnder setup</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rother, Tom</p> <p>2016-07-01</p> <p>In this paper I propose a classical optics experiment that results in a maximum violation of a Bell-like inequality. The first part is concerned with the Bell-like inequality (the so-called CHSH-inequality) itself. Its importance and its maximum violation in Quantum Mechanics (QM) are discussed in detail by employing an abstract probability state concept in a 4-dim. but classical event space. A T-matrix that represents the integral part of a corresponding Green's function as well as a statistical operator that contains a negative quasi-probability can be related to the corresponding quantum mechanical experiment. It is demonstrated that the derivation and usage of the T-matrix and the Green's function is equivalent to what is known from classical <span class="hlt">scattering</span> theory. It is shown moreover that the negative quasi-probability of the statistical operator may be interpreted as a sink of probabilities related to two single events of the considered 4-dim. event space. A necessary condition for the violation of the CHSH-inequality is derived and discussed afterwards. In the second part of this paper I discuss a modification of the 4-dim. event space considered in the first part. It is shown that a combination of conventional <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> with a Mach-Zehnder setup would be able to put this modification into practice. Thus it becomes possible to achieve a maximum violation of the CHSH-inequality, if formulated in terms of intensities, on a pure classical way. The combination of classical light <span class="hlt">scattering</span> with correlation experiments such as proposed in this paper may open new ways to study and to use the violation of Bell-like inequalities in modern optics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22493083','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22493083"><span id="translatedtitle">Confocal detection of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> for residual stress measurement in chemically tempered glass</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hödemann, S. Möls, P.; Kiisk, V.; Saar, R.; Kikas, J.; Murata, T.</p> <p>2015-12-28</p> <p>A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of <span class="hlt">scattered</span> laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na{sup +} ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional <span class="hlt">scattered</span> light tomography of mechanical imaging in birefringent materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...118x3103H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...118x3103H"><span id="translatedtitle">Confocal detection of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> for residual stress measurement in chemically tempered glass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hödemann, S.; Möls, P.; Kiisk, V.; Murata, T.; Saar, R.; Kikas, J.</p> <p>2015-12-01</p> <p>A new optical method is presented for evaluation of the stress profile in chemically tempered (chemically strengthened) glass based on confocal detection of <span class="hlt">scattered</span> laser beam. Theoretically, a lateral resolution of 0.2 μm and a depth resolution of 0.6 μm could be achieved by using a confocal microscope with high-NA immersion objective. The stress profile in the 250 μm thick surface layer of chemically tempered lithium aluminosilicate glass was measured with a high spatial resolution to illustrate the capability of the method. The confocal method is validated using transmission photoelastic and Na+ ion concentration profile measurement. Compositional influence on the stress-optic coefficient is calculated and discussed. Our method opens up new possibilities for three-dimensional <span class="hlt">scattered</span> light tomography of mechanical imaging in birefringent materials.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcSpA.126..135T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcSpA.126..135T"><span id="translatedtitle">Study on the interaction between albendazole and eosin Y by fluorescence, resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and frequency doubling <span class="hlt">scattering</span> spectra and their analytical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin</p> <p></p> <p>In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) and frequency doubling <span class="hlt">scattering</span> (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12509156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12509156"><span id="translatedtitle"><span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> study on the supramolecular interactions of beta-cyclodextrin derivatives with tetrakis(4-methoxylphenyl)porphyrin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Ronghua; Li, Ke'an; Wang, Kemin; Liu, Feng; Li, Na; Zhao, Fenglin</p> <p>2003-01-01</p> <p>The supramolecular interactions of beta-cyclodextrin(beta-CD) and four kinds of alkylated beta-cyclodextrin (beta-CDs), i.e. heptakis (2,6-di-O-isobutyl)-beta-cyclodextrin (Ob-beta-CD), heptakis (2,6-di-O-n-octyl)-beta-cyclodextrin (Oc-beta-CD), heptakis (2,6-di-O-n-dodecyl)-beta-cyclodextrin (Od-beta-CD) and heptakis (2,6-di-O-n-hexadecyl)-beta-cyclodextrin (Oh-beta-CD) with tetrakis(4-methoxylphenyl)porphyrin (TMOPP) have been investigated by <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> (RLS) technique. Beta-CDs form 2:1 inclusion complex with TMOPP following an obvious RLS enhancement of TMOPP. The inclusion abilities of different beta-CDs were compared. The results show that the inclusion ability of beta-CDs is related to the size of the alkylated substituent. Thus, a new mechanism of inclusion interaction has been proposed. The exact stoichiometric ratios and the association constants of the inclusion complexes have been examined by application of curve fitting method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/638296','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/638296"><span id="translatedtitle">Resonant <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> for the determination of trace amounts of mercury (II) with thiocyanate and basic triphenylmethane dyes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liu, S.; Liu, Z.; Zhou, G.</p> <p>1998-05-01</p> <p>Intense resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenylmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), malachite green (MG) or indine green (IG), to form an ion-association complex of the type (BTPMD){sub 2}[Hg(SCN){sub 4}]. The characteristics of RRS spectra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proportional to the concentration of mercury (II) in the range of 0--2.0 {micro}g/25 ml. The RRS methods have very high sensitivities for determination of mercury (II); their detection limits are between 1.68 ng/ml and 6.00 ng/ml on different dye systems. The effects of foreign ions and ways to improve the selectivity were studied. The new highly sensitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16455096','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16455096"><span id="translatedtitle">Incorporation of flow injection analysis or capillary electrophoresis with resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> detection for inorganic ion analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qi, Li; Han, Zhi-qiang; Chen, Yi</p> <p>2006-03-31</p> <p>Resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) has been explored as a detection (RRSD) technique for capillary electrophoresis (CE) or flow injection analysis (FIA) of inorganic ions. The detection was achieved through a <span class="hlt">scattering</span> probe of ion-association complex formed from rhodamine B (Rh B) and iodine. The probe <span class="hlt">scatters</span> strongly at 630 nm when oxidants such as Cr(2)O(7)(2-), MnO(4)(-) and ClO(-) present in a mixed solution of Rh B and iodide. The <span class="hlt">scattering</span> disappears once iodine is reduced by reductants. Oxidant or reductant species in a sample can thus be detected by positive or negative RRS signal. To verify the RRSD, FIA-RRSD was first constructed and continuous measurement of testing samples containing Cr(2)O(7)(2-), MnO(4)(-) and/or ClO(-) was performed. The detection limits reached a level of decade nM and a linear range was found between peak height and concentration at the range of 0.255-2.04microM for Cr(2)O(7)(2-), 0.158-3.16microM for MnO(4)(-), and 1.18-9.43microM for ClO(-), with linear regression coefficients of all above 0.99. The run-to-run relative standard deviation of peak height was less than 3% (n=6). CE-RRSD was then set up and studied, using a capillary of 75microm i.d.x33cm filled with a running buffer of 50mM citrate and 25mM Tris (pH 3.32) and worked under -12kV at room temperature. The CE eluent was at-line conducted into a stream of rhodamine B and iodine flowing inner a wide tube by plugging the capillary outlet into the wide tube. Different mixtures prepared from Cr(2)O(7)(2-), MnO(4)(-) and ClO(-) were successfully separated and detected by the CE-RRSD. PMID:16455096</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMOp...63.1886M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMOp...63.1886M"><span id="translatedtitle">Semi-classical dynamics of superradiant <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in a Bose-Einstein condensate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Müller, J. H.; Witthaut, D.; le Targat, R.; Arlt, J. J.; Polzik, E. S.; Hilliard, A. J.</p> <p>2016-10-01</p> <p>Due to its coherence properties and high optical depth, a Bose-Einstein condensate [BEC] provides an ideal setting to investigate collective atom-light interactions. Superradiant light <span class="hlt">scattering</span> [SLS] in a BEC is a fascinating example of such an interaction. It is an analogous process to Dicke superradiance, in which an electronically inverted sample decays collectively, leading to the emission of one or more light pulses in a well-defined direction. Through time-resolved measurements of the superradiant light pulses emitted by an end-pumped BEC, we study the close connection of SLS with Dicke superradiance. A 1D model of the system yields good agreement with the experimental data and shows that the dynamics result from the structures that build up in the light and matter-wave fields along the BEC. This paves the way for exploiting the atom-photon correlations generated by the superradiance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27409683','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27409683"><span id="translatedtitle">Enhancement of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in a two-dimensional Fabry-Perot resonator loaded with impurities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sadreev, Almas F</p> <p>2016-07-01</p> <p>We study wave transmission through a Fabry-Perot resonator (FPR) loaded with point-like impurities. We show both analytically in the framework of the coupled mode theory and numerically that there are two different regimes for transmission dependent on the quality of the FPR mirrors. For low quality, we obtain transmittance very similar to the clean FPR with slightly shifted Lorentz peaks. However, for good quality, the transmittance peaks are strongly reduced and substituted with Gaussian peaks because of multiple <span class="hlt">scattering</span> of waves by each impurity. As a side effect, we observe the angular (channel) conversion in the disordered FPR. We demonstrate that the resonant peaks are dependent on the concentration of impurities to pave a way for resonant measurement of the concentration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070021761','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070021761"><span id="translatedtitle">Development of a <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span> Diagnostic for Time-Resolved Gas Flow Velocity, Temperature, and Density Measurements in Aerodynamic Test Facilities</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen</p> <p>2007-01-01</p> <p>A molecular <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded turbulent flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and <span class="hlt">Rayleigh</span> <span class="hlt">scattered</span> light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultiplier tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. An acoustically driven nozzle flow is studied to validate velocity fluctuation measurements, and an asymmetric oscillating counterflow with unequal enthalpies is studied to validate the measurement of temperature fluctuations. Velocity fluctuations are compared with constant temperature anemometry measurements and temperature fluctuations are compared with constant current anemometry measurements at the same locations. Time-series and power spectra of the temperature and velocity measurements are presented. A numerical simulation of the light <span class="hlt">scattering</span> and detection process was developed and compared with experimental data for future use as an experiment design tool.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SuScT..26j5015C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SuScT..26j5015C"><span id="translatedtitle">Spatial and temporal resolution requirements for quench detection in (RE)Ba2Cu3Ox magnets using <span class="hlt">Rayleigh-scattering</span>-based fiber optic distributed sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, W. K.; Flanagan, G.; Schwartz, J.</p> <p>2013-10-01</p> <p>One of the key remaining challenges to safe and reliable operation of large, high temperature superconductor (HTS)-based magnet systems is quench detection and protection. Due to the slow quench propagation in HTS systems, the conventional discrete voltage-tap approach developed for NbTi and Nb3Sn magnets may not be sufficient. In contrast, a distributed temperature profile, generated by a distributed temperature sensor and facilitating continuous monitoring of the temperature at any monitored locations within a magnet with high spatial resolution, may be required. One such distributed temperature sensing option is the use of <span class="hlt">Rayleigh</span>-based fiber optic sensors (FOS), which are immune to electromagnetic interference. The detection of a quench via <span class="hlt">Rayleigh</span>-based FOS relies on converting the spectral shifts in the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> spectra into temperature variations. As a result, the higher the spatial sampling resolution the larger the data processing volume, and thus the lower the temporal sampling resolution. So, for effective quench detection, which requires the quick and accurate identification of a hot spot, it is important to find a balance between the spatial and temporal resolutions executable on a given data acquisition and processing (DAQ) system. This paper discusses a method for finding an appropriate DAQ technology that matches the characteristic of a superconducting coil, and determining the acceptable resolutions for efficient and safe quench detection. A quench detection algorithm based on distributed temperature sensing is proposed and its implementation challenges are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920066946&hterms=zones+ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dzones%2Bocean','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920066946&hterms=zones+ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dzones%2Bocean"><span id="translatedtitle">Surface roughness considerations for atmospheric correction of ocean color sensors. I - The <span class="hlt">Rayleigh-scattering</span> component. II - Error in the retrieved water-leaving radiance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gordon, Howard R.; Wang, Menghua</p> <p>1992-01-01</p> <p>The first step in the Coastal Zone Color Scanner (CZCS) atmospheric-correction algorithm is the computation of the <span class="hlt">Rayleigh-scattering</span> (RS) contribution, L sub r, to the radiance leaving the top of the atmosphere over the ocean. In the present algorithm, L sub r is computed by assuming that the ocean surface is flat. Calculations of the radiance leaving an RS atmosphere overlying a rough Fresnel-reflecting ocean are presented to evaluate the radiance error caused by the flat-ocean assumption. Simulations are carried out to evaluate the error incurred when the CZCS-type algorithm is applied to a realistic ocean in which the surface is roughened by the wind. In situations where there is no direct sun glitter, it is concluded that the error induced by ignoring the <span class="hlt">Rayleigh</span>-aerosol interaction is usually larger than that caused by ignoring the surface roughness. This suggests that, in refining algorithms for future sensors, more effort should be focused on dealing with the <span class="hlt">Rayleigh</span>-aerosol interaction than on the roughness of the sea surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcSpA.122...75T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcSpA.122...75T"><span id="translatedtitle">Study on interaction between palladium(ІІ)-Linezolid chelate with eosin by resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, second order of <span class="hlt">scattering</span> and frequency doubling <span class="hlt">scattering</span> methods using Taguchi orthogonal array design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.</p> <p>2014-03-01</p> <p>Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span> (RRS), Second-order <span class="hlt">Scattering</span> (SOS) and Frequency Doubling <span class="hlt">Scattering</span> (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the <span class="hlt">scattering</span> intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for <span class="hlt">scattering</span> intensity enhancement was discussed in this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApPhB.116..681S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApPhB.116..681S"><span id="translatedtitle">Improvements in filtered <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> measurements using Fabry-Perot etalons for spectral filtering of pulsed, 532-nm Nd:YAG output</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutton, Jeffrey A.; Patton, Randy A.</p> <p>2014-09-01</p> <p>In this manuscript, we investigate a new methodology for increasing the spectral purity of the second-harmonic output of an injection-seeded, frequency-doubled, Q-switched Nd:YAG laser operating near 532 nm. Specifically, tunable Fabry-Perot etalons (FPEs) are used as ultra-narrowband spectral filters, transmitting the desired single-mode output, while filtering out a significant portion of the broadband pedestal characteristic of injection-seeded lasers. A specific emphasis is placed on the design and optimization of the FPEs in the context of filtered <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (FRS) measurements and how their utilization results in substantial increases in spectral purity, realizable attenuation of unwanted <span class="hlt">scattering</span>, and applications in environments with high particulate levels. Experimental results show an increase in laser spectral purity of more than one order-of-magnitude (from 0.99997 to 0.999998) when using FPE filters, which led to a two-order-of-magnitude increase in achievable attenuation of laser light passing through a molecular iodine filter. The utility of the FPE-based spectral filtering of the pulsed Nd:YAG output for 2D FRS imaging was demonstrated in turbulent, isothermal gas-phase jets, seeded with varying levels of non-evaporating droplets with particle volume fractions ( F Vp) ranging from ~5 to >60 parts-per-million (ppm). After implementation of an optimized air-spaced FPE in the 532-nm output, no particle <span class="hlt">scattering</span> was observed (based on visual and statistical analysis), even for the highest seed case ( F Vp ~ 60 ppm), and the gas-phase <span class="hlt">Rayleigh</span>-Brillouin signals were collected without interference from the flowfield particulate. The current results suggest that the implementation of properly specified FPEs allows FRS to be applied in environments with high flowfield particulate levels; levels are well beyond what have been suitable for previous FRS measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985SPIE..540..643H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985SPIE..540..643H"><span id="translatedtitle">Banquet Speech Some Sketches Of <span class="hlt">Rayleigh</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howard, John N.</p> <p>1985-11-01</p> <p>Several short sketches are presented of Lord <span class="hlt">Rayleigh</span>, to show his method of working and his interaction with his fellow scientists. The topics discussed are: his research on the blue of the sky (<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>); his rescue of Waterston from near-oblivion; his research on surface acoustic waves (<span class="hlt">Rayleigh</span> waves); his collaboration with Agnes Pockels; his research on blackbody radiation (the <span class="hlt">Rayleigh</span>-Jeans Law).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25794718','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25794718"><span id="translatedtitle">Highly sensitive and selective determination of fluorine ion by graphene oxide/nanogold resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>-energy transfer analytical platform.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liang, Aihui; Peng, Jing; Liu, Qingye; Wen, Guiqing; Lu, Zhujun; Jiang, Zhiliang</p> <p>2015-08-15</p> <p>In pH 4.0 acetate buffer solution, fluorine ions react with fluorine reagent (FR) and La(III) to generate blue ternary complex that exhibited strong absorption at about 370 nm. Upon addition of graphene oxide/nanogold (GO/NG) as resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) spectral probe with strong RRS peak at 370 nm, the color changed to gray, and the RRS intensity decreased with the increase of fluorine ion concentration due to the RRS energy transfer (RRSET) from GO/NG to the complex. Under the selected condition, the decreased RRS peak ΔI370 nm was linear to fluorine ion concentration in the range of 6.0 × 10(-8)-1.3 × 10(-5)mol/L, with a detection limit of 3.0 × 10(-8)mol/L F(-). This RRSET method was applied to the analysis of fluorine in toothpaste and water samples, with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24124025','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24124025"><span id="translatedtitle">A simple and sensitive resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> method for determination of As(III) using aptamer-modified nanogold as a probe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tang, Meiling; Wen, Guiqing; Liang, Aihui; Jiang, Zhiliang</p> <p>2014-09-01</p> <p>A simple and selective aptamer (ssDNA)-modified nanogold probe (AussDNA) was prepared for the determination of trace As(III) in HEPES buffer solution (pH 8.2) containing 0.05 mol/L NaCl. The method coupled the aptamer reaction of AussDNA-As(III) and the resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) of nanogold aggregations at 278 nm. When the As(III) concentration increased, the RRS intensity at 278 nm increased to form more nanogold aggregation and a stable As(III)-ssDNA complex. Under selected conditions, the increased RRS intensity (ΔI) was linear to the concentration of As(III) in the range 3.8-230.4 ng/mL, with a detection limit of 1.9 ng/mL. This RRS method was applied to detect As(III) in water samples, with simplicity, sensitivity and selectivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24769380','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24769380"><span id="translatedtitle">Incorporation of flow injection analysis with dual-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> for rapid determination of malachite green and its metabolite in fish.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli</p> <p>2014-09-15</p> <p>A flow injection analysis (FIA) system combined with dual-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (DWO-RRS) has been established and validated for rapid determination of malachite green (MG) and its metabolite in fish samples. Under experimental condition, MG would react with Erythrosin (Ery) to form ion-association complexes, resulting in the occurrence of two RRS peaks and a dramatic enhancement of RRS intensity. The maximum RRS peaks were located at 286 nm and 337 nm. It is noted that the increments of both of these two peaks were proportional to the concentration of MG. The detection limit of DWO-RRS was 1.5 ng/mL, which was comparable to several reported methods. Moreover, the results of real sample analysis exhibited an acceptable recovery between 97.5% and 103.6%, indicating that the method had good reproducibility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcSpA.130...90Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcSpA.130...90Z"><span id="translatedtitle">Incorporation of flow injection analysis with dual-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> for rapid determination of malachite green and its metabolite in fish</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Jinghui; Qin, Mingyou; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli</p> <p>2014-09-01</p> <p>A flow injection analysis (FIA) system combined with dual-wavelength overlapping resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (DWO-RRS) has been established and validated for rapid determination of malachite green (MG) and its metabolite in fish samples. Under experimental condition, MG would react with Erythrosin (Ery) to form ion-association complexes, resulting in the occurrence of two RRS peaks and a dramatic enhancement of RRS intensity. The maximum RRS peaks were located at 286 nm and 337 nm. It is noted that the increments of both of these two peaks were proportional to the concentration of MG. The detection limit of DWO-RRS was 1.5 ng/mL, which was comparable to several reported methods. Moreover, the results of real sample analysis exhibited an acceptable recovery between 97.5% and 103.6%, indicating that the method had good reproducibility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.446.2428S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.446.2428S"><span id="translatedtitle">HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sing, D. K.; Wakeford, H. R.; Showman, A. P.; Nikolov, N.; Fortney, J. J.; Burrows, A. S.; Ballester, G. E.; Deming, D.; Aigrain, S.; Désert, J.-M.; Gibson, N. P.; Henry, G. W.; Knutson, H.; Lecavelier des Etangs, A.; Pont, F.; Vidal-Madjar, A.; Williamson, M. W.; Wilson, P. A.</p> <p>2015-01-01</p> <p>We present Hubble Space Telescope optical and near-IR transmission spectra of the transiting hot-Jupiter WASP-31b. The spectrum covers 0.3-1.7 μm at a resolution R ˜ 70, which we combine with Spitzer photometry to cover the full-optical to IR. The spectrum is dominated by a cloud deck with a flat transmission spectrum which is apparent at wavelengths > 0.52 μm. The cloud deck is present at high altitudes and low pressures, as it covers the majority of the expected optical Na line and near-IR H2O features. While Na I absorption is not clearly identified, the resulting spectrum does show a very strong potassium feature detected at the 4.2σ confidence level. Broadened alkali wings are not detected, indicating pressures below ˜10 mbar. The lack of Na and strong K is the first indication of a sub-solar Na/K abundance ratio in a planetary atmosphere (ln[Na/K] = -3.3 ± 2.8), which could potentially be explained by Na condensation on the planet's night side, or primordial abundance variations. A strong <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> signature is detected at short wavelengths, with a 4σ significant slope. Two distinct aerosol size populations can explain the spectra, with a smaller sub-micron size grain population reaching high altitudes producing a blue <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> signature on top of a larger, lower lying population responsible for the flat cloud deck at longer wavelengths. We estimate that the atmospheric circulation is sufficiently strong to mix micron size particles upwards to the required 1-10 mbar pressures, necessary to explain the cloud deck. These results further confirm the importance of clouds in hot Jupiters, which can potentially dominate the overall spectra and may alter the abundances of key gaseous species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2270354','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2270354"><span id="translatedtitle">Neutron activation analysis and X-ray <span class="hlt">Rayleigh</span> and Raman <span class="hlt">scattering</span> of hair and nail clippings as noninvasive bioindicators for Cu liver status in Labrador Retrievers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bueno, Maria Izabel Maretti Silveira; Bortoleto, Gisele G.; Hoffmann, Gaby; van den Ingh, Ted S. G. A. M.; Rothuizen, Jan</p> <p>2008-01-01</p> <p>The heritability of chronic hepatitis in the Labrador Retriever is studied with the aim of identifying the related gene mutation. Identification of cases and controls is largely based on instrumental neutron activation analysis (INAA) Cu determination in liver biopsies. The burden for these companion animals may be reduced if nail clippings and hair (fur) could serve as a noninvasive indicator for the hepatic Cu concentrations. No correlation was found between hepatic Cu concentrations and Cu concentrations in hair and nail samples. However, hair and nail samples were also analyzed by X-ray tube excitation, taking advantage of the X-ray Compton, <span class="hlt">Rayleigh</span>, and Raman <span class="hlt">scattering</span> which reflects the organic components such as the type of melanin. Principal component analysis provided first indications that some differentiation between healthy and sick dogs could indeed be obtained from hair and nail analysis. Figure Principal component analysis of <span class="hlt">scattered</span> region of x-ray fluorescence spectra of Labrador dog nails, demonstrating the differentiation towards dogs with high and low Cu liver levels (respectively positive and negative PC2 values) reflecting hepatitis, as well as gender (PC1: negative values for female and positive values for males) PMID:18264701</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27505442','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27505442"><span id="translatedtitle">Bacterial Light-Harvesting Complexes Showing Giant Second-Order Nonlinear Optical Response as Revealed by Hyper-<span class="hlt">Rayleigh</span> Light <span class="hlt">Scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Fei; Yu, Long-Jiang; Ma, Xiao-Hua; Wang, Peng; Wang-Otomo, Zheng-Yu; Zhang, Jian-Ping</p> <p>2016-09-01</p> <p>The second-order nonlinear optical (NLO) properties of light-harvesting complexes (LHs) from the purple photosynthetic bacteria Thermochromatium (Tch.) tepidum were investigated for the first time by means of hyper-<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (HRS). The carotenoid (Car) molecules bound to the isolated LH1 and LH2 proteins gave rise to second-harmonic <span class="hlt">scattering</span>; however, they showed an opposite effect of the collective contribution from Car, that is, the first hyperpolarizability (β) reduced substantially from (10 510 ± 370) × 10(-30) esu for LH1 to (360 ± 120) × 10(-30) esu for LH2. Chromatophores of Tch. tepidum also showed a giant hyperpolarizability of (11 640 ± 630) × 10(-30) esu. On the basis of the structural information on bacterial LHs, it is found that the effective β of an LH is governed by the microenvironment and orientational correlation among the Car chromophores, which is concluded to be coherently enhanced for LH1. For LH2, however, additional destructive effects between different Car molecules may account for the small β value. This work demonstrates that LH1 and native membranes of purple bacteria can be potent NLO materials and that HRS is a promising spectroscopic means for investigating structural information of pigment-protein supramolecules. PMID:27505442</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPB.368..129P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPB.368..129P"><span id="translatedtitle">Refinement of the Compton-<span class="hlt">Rayleigh</span> <span class="hlt">scatter</span> ratio method for use on the Mars Science Laboratory alpha particle X-ray spectrometer: II - Extraction of invisible element content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perrett, Glynis M.; Campbell, John L.; Gellert, Ralf; King, Penelope L.; Nield, Emily; O'Meara, Joanne M.; Pradler, Irina</p> <p>2016-02-01</p> <p>The intensity ratio C/R between Compton and <span class="hlt">Rayleigh</span> <span class="hlt">scatter</span> peaks of the exciting Pu L X-rays in the alpha particle X-ray spectrometer (APXS) is strongly affected by the presence of very light elements such as oxygen which cannot be detected directly by the APXS. C/R values are determined along with element concentrations by fitting APXS spectra of geochemical reference materials (GRMs) with the GUAPX code. A quantity K is defined as the ratio between the C/R value determined by Monte Carlo simulation based on the measured element concentrations and the fitted C/R value from the spectrum. To ensure optimally accurate K values, the choice of appropriate GRMs is explored in detail, with attention paid to Rb and Sr, whose characteristic Kα X-ray peaks overlap the Pu Lα <span class="hlt">scatter</span> peaks. The resulting relationship between the ratio K and the overall oxygen fraction is linear. This provides a calibration from which the concentration of additional light invisible constituents (ALICs) such as water may be estimated in unknown rock and conglomerate samples. Several GRMs are used as 'unknowns' in order to evaluate the accuracy of ALIC concentrations derived in this manner.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AcSpA.105..612W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AcSpA.105..612W"><span id="translatedtitle">Study on the interactions of antiemetic drugs and 12-tungstophosphoric acid by absorption and resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> spectra and their analytical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yaqiong; Liu, Shaopu; Liu, Zhongfang; Yang, Jidong; Hu, Xiaoli</p> <p>2013-03-01</p> <p>In 0.1 mol L-1 HCl medium, antiemetic drugs (ATM), such as granisetron hydrochloride (GS) and tropisetron hydrochloride (TS), reacted with H3PW12O40·nH2O and formed 3:1 ion-association complex of [(ATM)3PW12O40], then self-aggregated into nanoparticles-[(ATM)3PW12O40]n with an average size of 100 nm. The reaction resulted in the enhancement of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) and the absorption spectra. The increments of <span class="hlt">scattering</span> intensity (ΔIRRS) and the change of absorbance (ΔA) were both directly proportional to the concentrations of ATM in certain ranges. Accordingly, two new RRS and spectrophotometric methods were proposed for ATM detection. The detection limits (3σ) of GS and TS were 3.2 ng mL-1 and 4.0 ng mL-1(RRS method), 112.5 ng mL-1 and 100.0 ng mL-1(spectrophotometric method). These two methods were applied to determine GS in orally disintegrating tablets and the results were in good agreement with the official method. The ground-state geometries and electronic structures of GS and TS were optimized by the hybrid density functional theory (DFT) method and the shape of [(ATM)3PW12O40]n was characterized by atomic force microscopy (AFM). Take the RRS method with higher sensitivity as an example, the reaction mechanism and the reasons for enhancement of <span class="hlt">scattering</span> were discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcSpA.167...19Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcSpA.167...19Y"><span id="translatedtitle">In-situ formation of ion-association nanoparticles induced enhancements of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> intensities for quantitative analysis of trace Hg2 + ions in environmental samples</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Qingling; Liu, Jian; Li, Banglin; Hu, Xiaoli; Liu, Shaopu; Chen, Gangcai</p> <p>2016-10-01</p> <p>In this paper, Hg2 + ions are demonstrated to form anionic [HgI4]2 - complexes after interacting with massive amount of I- ions. Subsequently, the addition of tetradecyl pyridyl bromide (TPB) can make [HgI4]2 - anionic complexes react with univalent tetradecyl pyridyl cationic ions (TP+), forming dispersed ion-association complexes (TP)2(HgI4). Due to the extrusion action of water and Van der Waals force, the hydrophobic ion-association complexes aggregate together, forming dispersed nanoparticles with an average size of about 8.5 nm. Meanwhile, resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) intensity is apparently enhanced due to the formation of (TP)2(HgI4) ion-association nanoparticles, contributing to a novel technique for Hg2 + detection. The wavelength of 365 nm is chosen as a detection wavelength and several conditions affecting the RRS responses of Hg2 + are optimized. Under the optimum condition, the developed method is used for the determination of Hg2 + in aqueous solution and the detection limit is estimated to be 0.8 ng mL- 1. Finally, the practical application of the developed method can be confirmed through the detections of Hg2 + in waste and river water samples with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27096866','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27096866"><span id="translatedtitle">Resonance <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span> Spectra of an Ion-Association Complex of Naphthol Green B-Chitosan System and Its Application in the Highly Sensitive Determination of Chitosan.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan</p> <p>2016-04-01</p> <p>This work describes a highly-sensitive and accurate approach for the determination of chitosan (CTS) using Naphthol Green B (NGB) as a probe in the Resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) method. The interaction between CTS and NGB leads to notable enhancement of RRS, and the enhancement is proportional to the concentration of CTS over a certain range. Under optimum conditions, the calibration curve of ΔI against CTS concentration was ΔI = 1860.5c + 86.125 (c, µg/mL), R² = 0.9999, and the linear range and detection limit (DL) were 0.01-5.5 µg/mL and 8.87 ng/mL. Moreover, the effect of the molecular weight of CTS on the accurate quantification of CTS was studied. The experimental data were analyzed through linear regression analysis using SPSS20.0, and the molecular weight was found to have no statistical significance. This method has been applied to assay two CTS samples and obtained good recovery and reproducibility. PMID:27096866</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24637271','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24637271"><span id="translatedtitle">The resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> spectral investigation on the interaction of DNA with camellia sinensis in the presence of CPC and its analytical application.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bi, Shuyun; Wang, Tianjiao; Zhao, Tingting; Wang, Yu</p> <p>2014-06-01</p> <p>A novel method with high sensitivity was designed for the determination of trace nucleic acids by using cationic surfactant cetylpyridinium chloride (CPC) and camellia sinensis (CS) as resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> (RLS) probes. It was found DNA could combine with CS and CPC in Tris-HCl buffer (pH=7.4). Under optimum conditions, the RLS intensity of DNA can be enhanced by CPC-CS obviously at 294nm, and the enhanced RLS intensity was directly proportional to DNA concentration in the range from 0.024 to 3.48μgmL(-1) with a good linear relationship (r=0.9940). The limit of detection (LOD) was 1.49ngmL(-1) (S/N=3). In addition, the effects of some interferences including K(+), Na(+), Mg(2+), Zn(2+), Cu(2+), Ca(2+) and glucose on the determination were studied. The developed RLS assay was successfully applied to three synthetic samples to measure DNA, the recovery was 94.7-106.3% and RSD was 0.58-3.33%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcSpA.127..335B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcSpA.127..335B"><span id="translatedtitle">The resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> spectral investigation on the interaction of DNA with camellia sinensis in the presence of CPC and its analytical application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bi, Shuyun; Wang, Tianjiao; Zhao, Tingting; Wang, Yu</p> <p>2014-06-01</p> <p>A novel method with high sensitivity was designed for the determination of trace nucleic acids by using cationic surfactant cetylpyridinium chloride (CPC) and camellia sinensis (CS) as resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> (RLS) probes. It was found DNA could combine with CS and CPC in Tris-HCl buffer (pH = 7.4). Under optimum conditions, the RLS intensity of DNA can be enhanced by CPC-CS obviously at 294 nm, and the enhanced RLS intensity was directly proportional to DNA concentration in the range from 0.024 to 3.48 μg mL-1 with a good linear relationship (r = 0.9940). The limit of detection (LOD) was 1.49 ng mL-1 (S/N = 3). In addition, the effects of some interferences including K+, Na+, Mg2+, Zn2+, Cu2+, Ca2+ and glucose on the determination were studied. The developed RLS assay was successfully applied to three synthetic samples to measure DNA, the recovery was 94.7-106.3% and RSD was 0.58-3.33%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24957549','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24957549"><span id="translatedtitle">Synthesis of water-soluble Ag₂Se QDs as a novel resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> sensor for highly sensitive and selective ConA detection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Shuguang; Zhang, Lichun; Tang, Yurong; Lv, Yi</p> <p>2014-09-01</p> <p>Ag2Se quantum dots (QDs) have attracted a lot of interest due to their potential applications in biosensing and bioimaging. A strategy is presented that involves coupling of selenium powder reduction with the binding of silver ions, and thioglycollic acid (TGA) and glycine as stabilizers to obtain ultrasmall Ag2Se QDs at 85 °C in aqueous solution. This strategy avoids high temperatures, high pressures and organic solvents so that water-soluble 3 nm Ag2Se QDs can be directly obtained. The conjugation of ConA to TGA stabilized Ag2Se QDs by hydrogen bonds leads to the adsorption of ConA to Ag2Se QDs and forms the aggregation and leads to the generation of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) as a readout signal for the sensing events. The reaction mechanism of Ag2Se QD RRS enhancement is studied in this work. The resulting RRS sensor enables the detection of ConA with limit of detection reaching 0.08 μg mL(-1) concentration in a wide linear range from 0.27 μg mL(-1) to 35 μg mL(-1). The recovery of spiked ConA in human serum samples ranges from 94% to 106%. The relative standard deviation (RSD) for eleven replicate detections is 3.6%. Our results correlate many important experimental observations and will fuel the further growth of this field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AcSpA..90..158B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AcSpA..90..158B"><span id="translatedtitle">An investigation on the interaction of DNA with hesperetin/apigenin in the presence of CTAB by resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> technique and its analytical application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bi, Shuyun; Wang, Yu; Pang, Bo; Yan, Lili; Wang, Tianjiao</p> <p>2012-05-01</p> <p>Two new systems for measuring DNA at nanogram levels by a resonance <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> (RLS) technique with a common spectrofluorometer were proposed. In the presence of cetyltrimethylammonium bromide (CTAB), the interaction of DNA with hesperetin and apigenin (two effective components of Chinese herbal medicine) could enhance RLS signals with the maximum peak at 363 and 433 nm respectively. The enhanced intensity of RLS was directly proportional to the concentration of DNA in the range of 0.022-4.4 μg mL-1 for DNA-CTAB-hesperetin system and 0.013-4.4 μg mL-1 for DNA-CTAB-apigenin system. The detection limit was 2.34 ng mL-1 and 2.97 ng mL-1 respectively. Synthetic samples were measured satisfactorily. The recovery of DNA-CTAB-hesperetin system was 97.3-101.9% and that of DNA-CTAB-apigenin system was 101.2-109.5%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ExFl...39..375P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ExFl...39..375P"><span id="translatedtitle">Measurement of the conditioned turbulence and temperature field of a premixed Bunsen burner by planar laser <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and stereo particle image velocimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pfadler, Sebastian; Löffler, Micha; Dinkelacker, Friedrich; Leipertz, Alfred</p> <p>2005-08-01</p> <p>The turbulence and temperature field of Bunsen-type turbulent lean methane/air flames has been investigated using planar laser <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (PLRS) and stereo particle image velocimetry (stereo PIV). Temporally averaged reaction progress variable plots have been computed from PLRS measurements in order to provide a basis with regards to the verification of computational fluid dynamics (CFD) models. Turbulence was characterised by stereo PIV in one plane for all three velocity components. Averaged velocity fields have been calculated, as well as Reynolds-decomposed fluctuation vector fields. Conditioned root mean square (RMS) values of the turbulent fluctuations in terms of unburnt and burnt gas could be determined by making use of the information gained from a threshold setting procedure in the PIV raw images. Furthermore, several length scales were measured indirectly from PIV vector plots. In this context, all integral length scales being accessible with stereo PIV were computed separately for the burnt and unburnt regions and were compared to each other. It could be observed that all integral length scales increased in the burnt zone. Additionally, the conditioned Taylor and Kolmogorov lengths have been extracted from the PIV field data, derived either from the zero-radius curvature of the correlation function or from common turbulence theory relations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24010452','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24010452"><span id="translatedtitle">Observation of <span class="hlt">Rayleigh</span> phonon <span class="hlt">scattering</span> through excitation of extremely high overtones in low-loss cryogenic acoustic cavities for hybrid quantum systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goryachev, Maxim; Creedon, Daniel L; Galliou, Serge; Tobar, Michael E</p> <p>2013-08-23</p> <p>The confinement of high frequency phonons approaching 1 GHz is demonstrated in phonon-trapping acoustic cavities at cryogenic temperatures using a low-coupled network approach. The frequency range is extended by nearly an order of magnitude, with excitation at greater than the 200th overtone achieved for the first time. Such a high frequency operation reveals <span class="hlt">Rayleigh</span>-type phonon <span class="hlt">scattering</span> losses due to highly diluted lattice impurities and corresponding glasslike behavior, with a maximum Q(L)×f product of 8.6×10(17) at 3.8 K and 4×10(17) at 15 mK. This suggests a limit on the Q×f product due to unavoidable crystal disorder. Operation at 15 mK is high enough in frequency that the average phonon occupation number is less than unity, with a loaded quality factor above half a billion. This work represents significant progress towards the utilization of such acoustic cavities for hybrid quantum systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AcSpA..69...71L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AcSpA..69...71L"><span id="translatedtitle">A novel method for study of the aggregation of protein induced by metal ion aluminum(III) using resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Long, Xiufen; Zhang, Caihua; Cheng, Jiongjia; Bi, Shuping</p> <p>2008-01-01</p> <p>We present a novel method for the study of the aggregation of protein induced by metal ion aluminum(III) using resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) technique. In neutral Tris-HCl medium, the effect of this aggregation of protein results in the enhancement of RRS intensity and the relationship between the enhancement of the RRS signal and the Al concentration is nonlinear. On this basis, we established a new method for the determination of the critical induced-aggregation concentrations ( CCIAC) of metal ion Al(III) inducing the protein aggregation. Our results show that many factors, such as, pH value, anions, salts, temperature and solvents have obvious effects. We also studied the extent of aggregation and structural changes using ultra-violet spectrometry, protein intrinsic fluorescence and circular dichroism to further understand the exact mechanisms of the aggregation characteristics of proteins induced by metal ion Al(III) at the molecular level, to help us to develop effective methods to investigate the toxicity of metal ion Al, and to provide theoretical and quantitative evidences for the development of appropriate treatments for neurodementia such as Parkinson's disease, Alzheimer's disease and dementia related to dialysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4849075','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4849075"><span id="translatedtitle">Resonance <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span> Spectra of an Ion-Association Complex of Naphthol Green B–Chitosan System and Its Application in the Highly Sensitive Determination of Chitosan</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Weiai; Ma, Caijuan; Su, Zhengquan; Bai, Yan</p> <p>2016-01-01</p> <p>This work describes a highly-sensitive and accurate approach for the determination of chitosan (CTS) using Naphthol Green B (NGB) as a probe in the Resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) method. The interaction between CTS and NGB leads to notable enhancement of RRS, and the enhancement is proportional to the concentration of CTS over a certain range. Under optimum conditions, the calibration curve of ΔI against CTS concentration was ΔI = 1860.5c + 86.125 (c, µg/mL), R2 = 0.9999, and the linear range and detection limit (DL) were 0.01–5.5 µg/mL and 8.87 ng/mL. Moreover, the effect of the molecular weight of CTS on the accurate quantification of CTS was studied. The experimental data were analyzed through linear regression analysis using SPSS20.0, and the molecular weight was found to have no statistical significance. This method has been applied to assay two CTS samples and obtained good recovery and reproducibility. PMID:27096866</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20939548','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20939548"><span id="translatedtitle">First hyperpolarizability of the natural aromatic amino acids tryptophan, tyrosine, and phenylalanine and the tripeptide lysine-tryptophan-lysine determined by hyper-<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Duboisset, J; Matar, G; Russier-Antoine, I; Benichou, E; Bachelier, G; Jonin, Ch; Ficheux, D; Besson, F; Brevet, P F</p> <p>2010-11-01</p> <p>We report the first hyperpolarizability of tryptophan (Trp) and tyrosine (Tyr) and an upper limit for that of phenylalanine (Phe), three natural aromatic amino acids. The measurements were performed with hyper-<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in an aqueous Tris buffer solution at a pH of 8.5 and 150 mM salt concentration with a fundamental wavelength of 780 nm. A value of (4.7 ± 0.7) × 10(-30) esu is found for Trp and (4.1 ± 0.7) × 10(-30) esu for Tyr whereas the upper limit of 1.4 × 10(-30) esu is found for that of Phe due to its limited solubility. The influence of the presence of lysine (Lys) in close vicinity of Trp is investigated with a measurement of the first hyperpolarizabilty of Trp in an excess of Lys and compared to the first hyperpolarizability obtained for the tripeptide Lys-Trp-Lys. The clear decrease of the values measured in these two cases indicates that the first hyperpolarizabilty of Trp is very sensitive to its local environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27235829','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27235829"><span id="translatedtitle">In-situ formation of ion-association nanoparticles induced enhancements of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> intensities for quantitative analysis of trace Hg(2+) ions in environmental samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Qingling; Liu, Jian; Li, Banglin; Hu, Xiaoli; Liu, Shaopu; Chen, Gangcai</p> <p>2016-10-01</p> <p>In this paper, Hg(2+) ions are demonstrated to form anionic [HgI4](2-) complexes after interacting with massive amount of I(-) ions. Subsequently, the addition of tetradecyl pyridyl bromide (TPB) can make [HgI4](2-) anionic complexes react with univalent tetradecyl pyridyl cationic ions (TP(+)), forming dispersed ion-association complexes (TP)2(HgI4). Due to the extrusion action of water and Van der Waals force, the hydrophobic ion-association complexes aggregate together, forming dispersed nanoparticles with an average size of about 8.5nm. Meanwhile, resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) intensity is apparently enhanced due to the formation of (TP)2(HgI4) ion-association nanoparticles, contributing to a novel technique for Hg(2+) detection. The wavelength of 365nm is chosen as a detection wavelength and several conditions affecting the RRS responses of Hg(2+) are optimized. Under the optimum condition, the developed method is used for the determination of Hg(2+) in aqueous solution and the detection limit is estimated to be 0.8ngmL(-1). Finally, the practical application of the developed method can be confirmed through the detections of Hg(2+) in waste and river water samples with satisfactory results. PMID:27235829</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcSpA.156...22L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcSpA.156...22L"><span id="translatedtitle">A simple and rapid method for direct determination of Al(III) based on the enhanced resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> of hemin-functionalized graphene-Al(III) system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ling, Yu; Chen, Ling Xiao; Dong, Jiang Xue; Li, Nian Bing; Luo, Hong Qun</p> <p>2016-03-01</p> <p>A novel method for direct determination of Al(III) by using hemin-functionalized graphene (H-GO) has been established based on the enhancement of resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) intensity. The characteristics of RRS spectra, the optimum reaction conditions, and the reaction mechanism have been investigated. In this experiment, the Al(III) would exist in sol-gel Al(OH)3 species under the condition of pH 5.9 in aqueous solutions. When H-GO existed in the solution, the sol-gel Al(OH)3 would react with H-GO and result in enhancement of RRS intensity, owing to the enhanced hydrophobicity of H-GO surface. Therefore, a simple and rapid sensor for Al(III) was developed. The increased intensity of RRS is directly proportional to the concentration of Al(III) in the range of 10 nM-6 μM, along with a detection limit of 0.87 nM. Moreover, the sensor has been applied to determination of Al(III) concentration in real water and aspirin tablet samples with satisfactory results. Therefore, the proposed method is promising as an effective means for selective and sensitive determination of Al(III).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000eaa..bookE4796.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000eaa..bookE4796."><span id="translatedtitle"><span class="hlt">Rayleigh</span> Limit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murdin, P.</p> <p>2000-11-01</p> <p>The theoretical resolving power of a telescope according to a criterion devised by Lord <span class="hlt">Rayleigh</span> (1842-1919). Because of the phenomenon of diffraction the image of a point source of light (such as a star) produced even by a perfect optical instrument consists of a central bright spot (the Airy disk) surrounded by concentric dark and light rings. If two point sources are very close together, the r...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9783E..0AB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9783E..0AB"><span id="translatedtitle"><span class="hlt">Rayleigh</span> imaging in spectral mammography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berggren, Karl; Danielsson, Mats; Fredenberg, Erik</p> <p>2016-03-01</p> <p>Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton <span class="hlt">scattering</span>. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient <span class="hlt">scatter</span> rejection of the system enables measurement of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17375827','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17375827"><span id="translatedtitle">Lord <span class="hlt">Rayleigh</span>: John William Strutt, third Baron <span class="hlt">Rayleigh</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wells, Peter N T</p> <p>2007-03-01</p> <p>John William Strutt, first son of the second Baron <span class="hlt">Rayleigh</span>, was born on November 12, 1842. He was a sickly boy, so his schooling was sporadic. Nevertheless, he graduated first in his year at Cambridge and subsequently was a Fellow of Trinity College until his marriage in 1871. His father died in 1873, and he succeeded to the title third Baron <span class="hlt">Rayleigh</span>. He converted the stable block of his country house, Terling Place, into a laboratory. In 1879, he moved back to Cambridge as Professor of Experimental Physics, but he returned to Terling in 1884. He published The Theory of Sound in 1877/1878 and, in his lifetime, 466 scientific articles. He received the 1904 Nobel Prize in Physics for the discovery of argon and made numerous seminal contributions to scientific progress. In the field of acoustics, he studied <span class="hlt">scattering</span>, the diffraction limit, surface waves, resonance phenomena, reciprocity, streaming, radiation force, cavitation, relaxation, and binaural perception. He received many honors, was President of the Royal Society, one of the founding members of the Order of Merit, and Chancellor of Cambridge University. He also was interested in psychical research. Lord <span class="hlt">Rayleigh</span> died on June 30, 1919. PMID:17375827</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26163781','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26163781"><span id="translatedtitle">Cu²⁺ functionalized N-acetyl-L-cysteine capped CdTe quantum dots as a novel resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> probe for the recognition of phenylalanine enantiomers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Jidong; Tan, Xuanping; Zhang, Xiaoning; Yang, Qiong; Shen, Yizhong</p> <p>2015-01-01</p> <p>A simple protocol that can be used to simultaneously determinate enantiomers is extremely intriguing and useful. In this study, we proposed a low-cost, facile, sensitive method for simultaneous determination. The molecular recognition of Cu(2+) functionalized N-acetyl-l-cysteine capped CdTe quantum dots (Cu(2+)-NALC/CdTe QDs) with phenylalanine (PA) enantiomers was investigated based on the resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> (RRS) spectral technique. The RRS intensity of NALC/CdTe QDs is very weak, but Cu(2+) functionalized NALC/CdTe QDs have extremely high RRS intensity, the most important observations are that PA could quench the RRS intensity of Cu(2+)-NALC/CdTe QDs, and that l-PA and d-PA have different degree of influence. In addition, those experimental factors such as acidity, concentration of Cu(2+) and reaction time were investigated in regards to their effects on enantioselective interaction. Finally, the applicability of the chiral recognized sensor for the analysis of chiral mixtures on enantiomers has been demonstrated, and the results that were obtained high precision (<4.63%) and low error (<3.06%).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20709781','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20709781"><span id="translatedtitle">Passive retrieval of <span class="hlt">Rayleigh</span> waves in disordered elastic media</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Larose, Eric; Derode, Arnaud; Clorennec, Dominique; Margerin, Ludovic; Campillo, Michel</p> <p>2005-10-01</p> <p>When averaged over sources or disorder, cross correlation of diffuse fields yields the Green's function between two passive sensors. This technique is applied to elastic ultrasonic waves in an open <span class="hlt">scattering</span> slab mimicking seismic waves in the Earth's crust. It appears that the <span class="hlt">Rayleigh</span> wave reconstruction depends on the <span class="hlt">scattering</span> properties of the elastic slab. Special attention is paid to the specific role of bulk to <span class="hlt">Rayleigh</span> wave coupling, which may result in unexpected phenomena, such as a persistent time asymmetry in the diffuse regime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16383554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16383554"><span id="translatedtitle">Passive retrieval of <span class="hlt">Rayleigh</span> waves in disordered elastic media.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Larose, Eric; Derode, Arnaud; Clorennec, Dominique; Margerin, Ludovic; Campillo, Michel</p> <p>2005-10-01</p> <p>When averaged over sources or disorder, cross correlation of diffuse fields yields the Green's function between two passive sensors. This technique is applied to elastic ultrasonic waves in an open <span class="hlt">scattering</span> slab mimicking seismic waves in the Earth's crust. It appears that the <span class="hlt">Rayleigh</span> wave reconstruction depends on the <span class="hlt">scattering</span> properties of the elastic slab. Special attention is paid to the specific role of bulk to <span class="hlt">Rayleigh</span> wave coupling, which may result in unexpected phenomena, such as a persistent time asymmetry in the diffuse regime.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001RaPC...61..339C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001RaPC...61..339C"><span id="translatedtitle">90° Compton and <span class="hlt">Rayleigh</span> measurements and imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cesareo, R.; Balogun, F.; Brunetti, A.; Cappio Borlino, C.</p> <p>2001-06-01</p> <p>A simple apparatus for measurement and imaging of objects using <span class="hlt">scattered</span> X-rays was designed and constructed. This is composed of a well-collimated photon beam from an X-ray tube, a CZT thermoelectrically cooled semiconductor detector and an ( x, y, ϑ) translation-rotation table containing the object to be studied. First, the output beam was monochromatized; studies on Compton and <span class="hlt">Rayleigh</span> <span class="hlt">scattered</span> radiation were then carried out, including the Compton profile. Then direct bremsstrahlung radiation of proper energy was employed, and energy intervals are selected where <span class="hlt">Rayleigh</span> or Compton effects largely prevail. Compton images were finally obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012APS..DFD.G8002S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012APS..DFD.G8002S&link_type=ABSTRACT"><span id="translatedtitle">Sessile <span class="hlt">Rayleigh</span> drop instability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steen, Paul; Bostwick, Josh</p> <p>2012-11-01</p> <p><span class="hlt">Rayleigh</span> (1879) determined the mode shapes and frequencies of the inviscid motion of a free drop held by surface tension. We study the inviscid motions of a sessile <span class="hlt">Rayleigh</span> drop - a drop which rests on a planar solid and whose contact-line is free to move. Linear stability analysis gives the modes and frequencies of the droplet motions. In this talk, we focus on the ``walking instability,'' an unstable mode wherein the drop moves across a planar substrate in an inviscid rocking-like motion. The mode shape is non-axisymmetric. Although the experimental literature has hinted at such a mode, this is the first prediction from linear stability analysis, as far as we are aware. The ``walking instability'' of the drop converts energy stored in the liquid shape into the energy of liquid motion - which represents a heretofore unknown pathway of energy conversion of potentially wide significance for a broad range of applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22330519','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22330519"><span id="translatedtitle">Light spin forces in optical traps: comment on "Trapping metallic <span class="hlt">Rayleigh</span> particles with radial polarization".</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Iglesias, Ignacio; Sáenz, Juan José</p> <p>2012-01-30</p> <p>An incomplete modeling of the <span class="hlt">scattering</span> forces on a <span class="hlt">Rayleigh</span> particle without taking into account the light spin forces in "Trapping metallic <span class="hlt">Rayleigh</span> particles with radial polarization" by Q. Zhan, leads to erroneous statements on the advantages of using radial polarization to trap metallic particles. PMID:22330519</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JOSAA..12.1254T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JOSAA..12.1254T"><span id="translatedtitle">Relation between the <span class="hlt">Rayleigh</span> equation in diffraction theory and the equation based on Green's formula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tatarskii, V. I.</p> <p>1995-06-01</p> <p>The steps necessary to produce the <span class="hlt">Rayleigh</span> equation that is based on the <span class="hlt">Rayleigh</span> hypothesis from the equation that is based on the Green's formula are shown. First a definition is given for the <span class="hlt">scattering</span> amplitude that is true not only in the far zone of diffraction but also near the <span class="hlt">scattering</span> surface. With this definition the <span class="hlt">Rayleigh</span> equation coincides with the rigorous equation for the surface secondary sources that is based on Green's formula. The <span class="hlt">Rayleigh</span> hypothesis is equivalent to substituting the far-zone expression of the <span class="hlt">scattering</span> amplitude into this rigorous equation. In this case it turns out to be the equation not for the sources but directly for the <span class="hlt">scattering</span> amplitude, which is the main advantage of this method. For comparing the <span class="hlt">Rayleigh</span> equation with the initial rigorous equation, the <span class="hlt">Rayleigh</span> equation is represented in terms of secondary sources. The kernel of this equation contains an integral that converges for positive and diverges for negative values of some parameter. It is shown that if we regularize this integral, defining it for the negative values of this parameter as an analytical continuation from the domain of positive values, this kernel becomes equal to the kernel of the initial rigorous equation. It follows that the formal perturbation series for the <span class="hlt">scattering</span> amplitude obtained from the <span class="hlt">Rayleigh</span> equation and from Green's equation always coincide. This means that convergence of the perturbation series is a sufficient condition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000eaa..bookE4026.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000eaa..bookE4026."><span id="translatedtitle">Strutt, John William [Lord <span class="hlt">Rayleigh</span>] (1842-1919)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murdin, P.</p> <p>2000-11-01</p> <p>Born in Langford Grove (near Maldon), Essex, England, Nobel prizewinner (1904) for the discovery of argon. He worked in many areas of physics, including electromagnetism and sound; the <span class="hlt">Rayleigh</span> theory of the <span class="hlt">scattering</span> of light was the first correct explanation of why the sky is blue....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005APS..APRU11003M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005APS..APRU11003M"><span id="translatedtitle">The <span class="hlt">Rayleigh</span> Papers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Thomas; Bederson, Benjamin</p> <p>2005-04-01</p> <p>The Third Lord <span class="hlt">Rayleigh</span> (1842-1919), aka John William Strutt, was among the most stellar physicists of the Nineteenth Century, in both theory and experiment. He spent most of his mature years in his own laboratory, self-funded, on his family estate. One of the consequences was the fact that all of his papers remained at the estate upon his death. After his son's (Robert John Strutt, 1875-1947) death both their scientific papers ended up on the auction block. (Robert John was himself an atmospheric physicist.) Part of the Strutt collection went to the Burndy Library of the Dibner Institute at MIT, but most landed in the library at the US Air Force Cambridge Research Laboratory (now the Air Force Research Laboratory at Hansom AFB), purchased from the auctioneer out of library funds, for 9,000. The individual most responsible for preserving these papers was John N. Howard, the laboratory Chief Scientist, who was a founding editor of the journal Applied Optics. Recently the authors examined first hand the <span class="hlt">Rayleigh</span> papers. Included in these are a complete set of his handwritten scientific notes, taken over the period 1862-1919, from the time he was a student at Trinity College, Cambridge until just months before his death. We will show a number of interesting examples from these notes, including his first identification of argon, as well as some other fascinating items from the collection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005APS..DFD.NB012D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005APS..DFD.NB012D"><span id="translatedtitle">Microscopic <span class="hlt">Rayleigh</span> Droplet Beams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doak, R. B.</p> <p>2005-11-01</p> <p>A periodically triggered <span class="hlt">Rayleigh</span> Droplet Beam (RDB) delivers a perfectly linear and periodic stream of identical, monoenergetic droplets that are phase-locked to the trigger signal. The droplet diameter and spacing are easily adjusted of choice of nozzle diameter and trigger frequency. Any liquid of low viscosity may be emloyed as the beam fluid. Although the field of nanofluidics is expanding rapidly, little effort has yet been devoted to ``external flows'' such as RDB's. At ASU we have generated RDB's of water and methanol down to 2 microns in droplet diameter. Nozzle clogging is the sole impediment to smaller droplets. Microscopic <span class="hlt">Rayleigh</span> droplet beams offer tremendous potential for fundamental physical measurements, fluid dynamics research, and nanofabrication. This talk will describe the apparatus and techniques used at ASU to generate RDB's (surprisingly simple and inexpensive), discuss the triboelectric phenomena that play a role (surprisingly significant), present some initial experimental fluid dynamics measurements, and briefly survey RDB applications. Our particular interest in RDB's is as microscopic transport systems to deliver hydrated, undenatured proteins into vacuum for structure determination via serial diffraction of x-rays or electrons. This may offer the first general method for structure determination of non-crystallizable proteins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18360530','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18360530"><span id="translatedtitle">Spectral structure of laser light <span class="hlt">scattering</span> revisited: bandwidths of nonresonant <span class="hlt">scattering</span> lidars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>She, C Y</p> <p>2001-09-20</p> <p>It is well known that <span class="hlt">scattering</span> lidars, i.e., Mie, aerosol-wind, <span class="hlt">Rayleigh</span>, high-spectral-resolution, molecular-wind, rotational Raman, and vibrational Raman lidars, are workhorses for probing atmospheric properties, including the backscatter ratio, aerosol extinction coefficient, temperature, pressure, density, and winds. The spectral structure of molecular <span class="hlt">scattering</span> (strength and bandwidth) and its constituent spectra associated with <span class="hlt">Rayleigh</span> and vibrational Raman <span class="hlt">scattering</span> are reviewed. Revisiting the correct name by distinguishing Cabannes <span class="hlt">scattering</span> from <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, and sharpening the definition of each <span class="hlt">scattering</span> component in the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> spectrum, the review allows a systematic, logical, and useful comparison in strength and bandwidth between each <span class="hlt">scattering</span> component and in receiver bandwidths (for both nighttime and daytime operation) between the various <span class="hlt">scattering</span> lidars for atmospheric sensing. PMID:18360530</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22089441','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22089441"><span id="translatedtitle">Microwave <span class="hlt">scattering</span> from laser spark in air</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sawyer, Jordan; Zhang Zhili; Shneider, Mikhail N.</p> <p>2012-09-15</p> <p>In this paper, microwave Mie <span class="hlt">scattering</span> from a laser-induced plasma in atmospheric air is computed. It shows that the <span class="hlt">scattered</span> microwave transitions from coherent <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> to Mie <span class="hlt">scattering</span> based on the relative transparency of the laser-induced plasma at the microwave frequency. The microwave penetration in the plasma alters from total transparency to partial shielding due to the sharp increase of the electron number density within the avalanche ionization phase. The transition from <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> to Mie <span class="hlt">scattering</span> is verified by both the temporal evolution of the <span class="hlt">scattered</span> microwave and the homogeneity of polar <span class="hlt">scattering</span> plots.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAG...116...93W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAG...116...93W"><span id="translatedtitle">Effect of near-surface topography on high-frequency <span class="hlt">Rayleigh</span>-wave propagation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Limin; Xu, Yixian; Xia, Jianghai; Luo, Yinhe</p> <p>2015-05-01</p> <p><span class="hlt">Rayleigh</span> waves, which are formed due to interference of P- and Sv-waves near the free surface, propagate along the free surface and vanish exponentially in the vertical direction. Their propagation is strongly influenced by surface topography. Due to the high resolution and precision requirements of near-surface investigations, the high-frequency <span class="hlt">Rayleigh</span> waves are usually used for near-surface structural detecting. Although there are some numerical studies on high-frequency <span class="hlt">Rayleigh</span>-wave propagation on topographic free surface, detailed analysis of characters of high-frequency <span class="hlt">Rayleigh</span>-wave propagation on topographic free surface remains untouched. Hence, research of propagation of <span class="hlt">Rayleigh</span> waves on complex topographic surface becomes critical for <span class="hlt">Rayleigh</span>-wave methods in near-surface applications. To study the propagation of high-frequency <span class="hlt">Rayleigh</span> waves on topographic free surface, two main topographic models are designed in this study. One of the models contains a depressed topographic surface, and another contains an uplifted topographic surface. We numerically simulate the propagation of high-frequency <span class="hlt">Rayleigh</span> waves on these two topographic surfaces by finite-difference method. Soon afterwards, we analyze the propagation character of high-frequency <span class="hlt">Rayleigh</span> waves on such topographic models, and compare the variations on its energy and frequency before and after passing the topographic region. At last, we discuss the relationship between the variations and topographical steepness of each model. Our numerical results indicate that influence of depressed topography for high-frequency <span class="hlt">Rayleigh</span> waves is more distinct than influence of uplifted topography. <span class="hlt">Rayleigh</span> waves produce new <span class="hlt">scattering</span> body waves during passing the depressed topography with reduction of amplitude and loss of high-frequency components. Moreover, the steeper the depressed topography is, the more energy of <span class="hlt">Rayleigh</span> waves is lost. The uplifted topography with gentle slope produces similar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27410156','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27410156"><span id="translatedtitle"><span class="hlt">Rayleigh</span> radiance computations for satellite remote sensing: accounting for the effect of sensor spectral response function.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Menghua</p> <p>2016-05-30</p> <p>To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) <span class="hlt">Rayleigh-scattering</span> radiance computation, new TOA <span class="hlt">Rayleigh</span> radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new <span class="hlt">Rayleigh</span> LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new <span class="hlt">Rayleigh</span> LUTs, the sensor SRF effect on the accuracy of the TOA <span class="hlt">Rayleigh</span> radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large <span class="hlt">Rayleigh</span> optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA <span class="hlt">Rayleigh</span> radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the <span class="hlt">Rayleigh</span> radiance computation can be used for other satellite sensors. In addition, with the new <span class="hlt">Rayleigh</span> LUTs, the effect of surface atmospheric pressure variation on the TOA <span class="hlt">Rayleigh</span> radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new <span class="hlt">Rayleigh</span> LUTs for satellite remote sensing, including an efficient and accurate TOA <span class="hlt">Rayleigh</span> radiance computation for hyperspectral satellite remote sensing, detector-based TOA <span class="hlt">Rayleigh</span> radiance computation, <span class="hlt">Rayleigh</span> radiance calculations for high altitude</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27410156','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27410156"><span id="translatedtitle"><span class="hlt">Rayleigh</span> radiance computations for satellite remote sensing: accounting for the effect of sensor spectral response function.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Menghua</p> <p>2016-05-30</p> <p>To understand and assess the effect of the sensor spectral response function (SRF) on the accuracy of the top of the atmosphere (TOA) <span class="hlt">Rayleigh-scattering</span> radiance computation, new TOA <span class="hlt">Rayleigh</span> radiance lookup tables (LUTs) over global oceans and inland waters have been generated. The new <span class="hlt">Rayleigh</span> LUTs include spectral coverage of 335-2555 nm, all possible solar-sensor geometries, and surface wind speeds of 0-30 m/s. Using the new <span class="hlt">Rayleigh</span> LUTs, the sensor SRF effect on the accuracy of the TOA <span class="hlt">Rayleigh</span> radiance computation has been evaluated for spectral bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System (JPSS)-1, showing some important uncertainties for VIIRS-SNPP particularly for large solar- and/or sensor-zenith angles as well as for large <span class="hlt">Rayleigh</span> optical thicknesses (i.e., short wavelengths) and bands with broad spectral bandwidths. To accurately account for the sensor SRF effect, a new correction algorithm has been developed for VIIRS spectral bands, which improves the TOA <span class="hlt">Rayleigh</span> radiance accuracy to ~0.01% even for the large solar-zenith angles of 70°-80°, compared with the error of ~0.7% without applying the correction for the VIIRS-SNPP 410 nm band. The same methodology that accounts for the sensor SRF effect on the <span class="hlt">Rayleigh</span> radiance computation can be used for other satellite sensors. In addition, with the new <span class="hlt">Rayleigh</span> LUTs, the effect of surface atmospheric pressure variation on the TOA <span class="hlt">Rayleigh</span> radiance computation can be calculated precisely, and no specific atmospheric pressure correction algorithm is needed. There are some other important applications and advantages to using the new <span class="hlt">Rayleigh</span> LUTs for satellite remote sensing, including an efficient and accurate TOA <span class="hlt">Rayleigh</span> radiance computation for hyperspectral satellite remote sensing, detector-based TOA <span class="hlt">Rayleigh</span> radiance computation, <span class="hlt">Rayleigh</span> radiance calculations for high altitude</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvA..93d3807Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvA..93d3807Y&link_type=ABSTRACT"><span id="translatedtitle">Tractor beams in the <span class="hlt">Rayleigh</span> limit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yevick, Aaron; Ruffner, David B.; Grier, David G.</p> <p>2016-04-01</p> <p>A tractor beam is a traveling wave that transports illuminated objects back to its source, opposite to the wave's direction of propagation, along its entire length. The requisite retrograde force arises when an object <span class="hlt">scatters</span> the wave's momentum density downstream into the direction of propagation and then recoils upstream by conservation of momentum. Achieving this condition imposes constraints on the structure of the wave, which we elucidate in the <span class="hlt">Rayleigh</span> limit, when the wavelength exceeds the size of the object. Continuously propagation-invariant modes such as Bessel beams do not satisfy these conditions at dipole order in the multipole expansion and so cannot serve as general-purpose long-ranged tractor beams. Modes with discrete propagation invariance, however, can act as first-order tractor beams. We demonstrate this by introducing a class of minimal solenoidal waves together with a set of design criteria that distinguish tractor beams that pull objects from repulsor beams that push them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930060951&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dwater%2Bfilter','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930060951&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dwater%2Bfilter"><span id="translatedtitle"><span class="hlt">Rayleigh</span> rejection filters for 193-nm ArF laser Raman spectroscopy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mckenzie, Robert L.</p> <p>1993-01-01</p> <p>Selected organic absorbers and their solvents are evaluated as spectral filters for the rejection of 193-nm <span class="hlt">Rayleigh</span> light associated with the use of an ArF excimer laser for Raman spectroscopy. A simply constructed filter cell filled with 0.5 percent acetone in water and an optical path of 7 mm is shown effectively to eliminate stray <span class="hlt">Rayleigh</span> light underlying the Raman spectrum from air while transmitting 60 percent of the Raman light <span class="hlt">scattered</span> by O2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020050548','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020050548"><span id="translatedtitle">Assessing the <span class="hlt">Rayleigh</span> Intensity Remote Leak Detection Technique</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clements, Sandra</p> <p>2001-01-01</p> <p>Remote sensing technologies are being considered for efficient, low cost gas leak detection. An exploratory project to identify and evaluate remote sensing technologies for application to gas leak detection is underway. During Phase 1 of the project, completed last year, eleven specific techniques were identified for further study. One of these, the <span class="hlt">Rayleigh</span> Intensity technique, would make use of changes in the light <span class="hlt">scattered</span> off of gas molecules to detect and locate a leak. During the 10-week Summer Faculty Fellowship Program, the <span class="hlt">scatter</span> of light off of gas molecules was investigated. The influence of light <span class="hlt">scattered</span> off of aerosols suspended in the atmosphere was also examined to determine if this would adversely affect leak detection. Results of this study indicate that in unconditioned air, it will be difficult, though perhaps not impossible, to distinguish between a gas leak and natural variations in the aerosol content of the air. Because information about the particle size distribution in clean room environments is incomplete, the applicability in clean rooms is uncertain though more promising than in unconditioned environments. It is suggested that problems caused by aerosols may be overcome by using the <span class="hlt">Rayleigh</span> Intensity technique in combination with another remote sensing technique, the <span class="hlt">Rayleigh</span> Doppler technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1230250-thomson-scattering-lineshape-fitting-plasma-diagnostics','SCIGOV-ESTSC'); return false;" href="http://www.osti.gov/scitech/biblio/1230250-thomson-scattering-lineshape-fitting-plasma-diagnostics"><span id="translatedtitle">Thomson <span class="hlt">Scattering</span> Lineshape Fitting for Plasma Diagnostics</span></a></p> <p><a target="_blank" href=""></a></p> <p></p> <p>1994-02-04</p> <p>HFIT30 is used for interpreting lineshape (intensity versus frequency) data from Thomson and <span class="hlt">Rayleigh</span> light <span class="hlt">scattering</span> from a plasma, to obtain temperatures and number densities of the component species in the plasma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvF...1e4405B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvF...1e4405B"><span id="translatedtitle">Rotating <span class="hlt">Rayleigh</span>-Taylor turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boffetta, G.; Mazzino, A.; Musacchio, S.</p> <p>2016-09-01</p> <p>The turbulent <span class="hlt">Rayleigh</span>-Taylor system in a rotating reference frame is investigated by direct numerical simulations within the Oberbeck-Boussinesq approximation. On the basis of theoretical arguments, supported by our simulations, we show that the Rossby number decreases in time, and therefore the Coriolis force becomes more important as the system evolves and produces many effects on <span class="hlt">Rayleigh</span>-Taylor turbulence. We find that rotation reduces the intensity of turbulent velocity fluctuations and therefore the growth rate of the temperature mixing layer. Moreover, in the presence of rotation the conversion of potential energy into turbulent kinetic energy is found to be less effective, and the efficiency of the heat transfer is reduced. Finally, during the evolution of the mixing layer we observe the development of a cyclone-anticyclone asymmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25679119','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25679119"><span id="translatedtitle">Fano coupling between <span class="hlt">Rayleigh</span> anomaly and localized surface plasmon resonance for sensor applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Feifei; Zhang, Xinping</p> <p>2015-06-15</p> <p>Fano coupling between <span class="hlt">Rayleigh</span> anomaly and localized surface plasmon resonance has been observed in diffractive grating structures consisting of aluminum nanolines deposited on the top surface of photoresist with each nanoline composed of tightly aggregated aluminum nanoparticles. Localized surface plasmon resonance is excited both in the nanoparticles and in the nanolines by differently polarized light. The surface propagation mode excited by the first- and second-order <span class="hlt">Rayleigh</span> diffraction anomaly is strongly <span class="hlt">scattered</span> and diffracted by the plasmonic aluminum grating structures, producing light rays in the same direction as the reflected light beam with the same spectral feature as the <span class="hlt">Rayleigh</span> anomaly. The narrow-band diffracted and <span class="hlt">scattered</span> light appears as sharp dips in the broad-band reflective optical extinction spectrum of plasmon resonance, which is recognized as a kind of Fano coupling. This kind of coupled mode is utilized successfully in refractive-index-sensor devices with excellent sensitivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013815','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013815"><span id="translatedtitle">Asymptotic <span class="hlt">Rayleigh</span> instantaneous unit hydrograph</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Troutman, B.M.; Karlinger, M.R.</p> <p>1988-01-01</p> <p>The instantaneous unit hydrograph for a channel network under general linear routing and conditioned on the network magnitude, N, tends asymptotically, as N grows large, to a <span class="hlt">Rayleigh</span> probability density function. This behavior is identical to that of the width function of the network, and is proven under the assumption that the network link configuration is topologically random and the link hydraulic and geometric properties are independent and identically distributed random variables. The asymptotic distribution depends only on a scale factor, {Mathematical expression}, where ?? is a mean link wave travel time. ?? 1988 Springer-Verlag.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGE....12..365E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGE....12..365E"><span id="translatedtitle">Diffraction of <span class="hlt">Rayleigh</span> wave by simple surface irregularity using boundary element method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eslami Haghighat, Abbas</p> <p>2015-06-01</p> <p>The topographic amplification effect is studied in this paper in the case of a semi-circular canyon under incident <span class="hlt">Rayleigh</span> wave. Time-frequency domain boundary element method has been applied to investigate the wave diffraction phenomena. The model consists of a semi-circular canyon cut from an isotropic elastic half plane. The total response is decomposed into free field motion and <span class="hlt">scattered</span> wave field. The former can be constructed analytically by superposing on incident and reflected <span class="hlt">Rayleigh</span> waves in the half plane and the later by using boundary element method with linear elements. The analyses are performed in the frequency domain and then converted into time domain using fast Fourier transform (FFT) algorithm. It is shown that the weak and strong singularities in the governing integral equations for linear elements can be removed by analytical approaches. Different ranges of <span class="hlt">Rayleigh</span> wavelengths from low to high are considered. The results are presented versus dimensionless frequency and distance. A limiting value for <span class="hlt">Rayleigh</span> wavelength can be recognized beyond which the canyon has no important effects on <span class="hlt">scattering</span> of harmonic incident waves. Furthermore, a parametric study has been performed for different values of Poisson’s ratios. The published works in the effects of this parameter are somewhat few and limited to specific values of Poisson’s ratio. Finally, the spatial variations of surface displacements for the <span class="hlt">Rayleigh</span> wave impulse of Ricker wavelet type are obtained. The spatial distribution shows the generation of backward-<span class="hlt">scattered</span> <span class="hlt">Rayleigh</span> wave which its intensity depends on predominant frequency of the input impulse as well as Poisson’s ratio of the medium. Dynamic responses of the points just located at the edges of the semi-circular canyon are compared to each other which accounts for the isolation efficiency of the canyon.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21574842','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21574842"><span id="translatedtitle">RADIATIVE <span class="hlt">RAYLEIGH</span>-TAYLOR INSTABILITIES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jacquet, Emmanuel; Krumholz, Mark R. E-mail: krumholz@ucolick.org</p> <p>2011-04-01</p> <p>We perform analytic linear stability analyses of an interface separating two stratified media threaded by a radiation flux, a configuration relevant in several astrophysical contexts. We develop a general framework for analyzing such systems and obtain exact stability conditions in several limiting cases. In the optically thin, isothermal regime, where the discontinuity is chemical in nature (e.g., at the boundary of a radiation pressure-driven H II region), radiation acts as part of an effective gravitational field, and instability arises if the effective gravity per unit volume toward the interface overcomes that away from it. In the optically thick 'adiabatic' regime where the total (gas plus radiation) specific entropy of a Lagrangian fluid element is conserved, for example at the edge of radiation pressure-driven bubble around a young massive star, we show that radiation acts like a modified equation of state and derive a generalized version of the classical <span class="hlt">Rayleigh</span>-Taylor stability condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/971276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/971276"><span id="translatedtitle">Nonideal <span class="hlt">Rayleigh</span>-Taylor mixing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sharp, David Howland; Lin, Hyun K; Iwerks, Justin G; Gliman, James G</p> <p>2009-01-01</p> <p><span class="hlt">Rayleigh</span>-Taylor mixing is a classical hydrodynamic Instability, which occurs when a light fluid pushes against a heavy fluid. The two main sources of nonideal behavior in <span class="hlt">Rayleigh</span>-Taylor (RT) mixing are regularizations (physical and numerical) which produce deviations from a pure Euler equation, scale Invariant formulation, and non Ideal (i.e. experimental) initial conditions. The Kolmogorov theory of turbulence predicts stirring at all length scales for the Euler fluid equations without regularization. We Interpret mathematical theories of existence and non-uniqueness in this context, and we provide numerical evidence for dependence of the RT mixing rate on nonideal regularizations, in other words indeterminacy when modeled by Euler equations. Operationally, indeterminacy shows up as non unique solutions for RT mixing, parametrized by Schmidt and Prandtl numbers, In the large Reynolds number (Euler equation) limit. Verification and validation evidence is presented for the large eddy simulation algorithm used here. Mesh convergence depends on breaking the nonuniqueness with explicit use of the laminar Schmidt and PrandtJ numbers and their turbulent counterparts, defined in terms of subgrid scale models. The dependence of the mixing rate on the Schmidt and Prandtl numbers and other physical parameters will be illustrated. We demonstrate numerically the influence of initial conditions on the mixing rate. Both the dominant short wavelength Initial conditions and long wavelength perturbations are observed to playa role. By examination of two classes of experiments, we observe the absence of a single universal explanation, with long and short wavelength initial conditions, and the various physical and numerical regularizations contributing In different proportions In these two different contexts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/991721','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/991721"><span id="translatedtitle">Nonideal <span class="hlt">Rayleigh</span>-Taylor Mixing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lim, H.; Glimm, J.; Iwerks, J.; Sharp, D.H.</p> <p>2010-08-01</p> <p><span class="hlt">Rayleigh</span>-Taylor mixing is a classical hydrodynamic instability that occurs when a light fluid pushes against a heavy fluid. The two main sources of nonideal behavior in <span class="hlt">Rayleigh</span>-Taylor (RT) mixing are regularizations (physical and numerical), which produce deviations from a pure Euler equation, scale invariant formulation, and nonideal (i.e., experimental) initial conditions. The Kolmogorov theory of turbulence predicts stirring at all length scales for the Euler fluid equations without regularization. We interpret mathematical theories of existence and nonuniqueness in this context, and we provide numerical evidence for dependence of the RT mixing rate on nonideal regularizations; in other words, indeterminacy when modeled by Euler equations. Operationally, indeterminacy shows up as nonunique solutions for RT mixing, parametrized by Schmidt and Prandtl numbers, in the large Reynolds number (Euler equation) limit. Verification and validation evidence is presented for the large eddy simulation algorithm used here. Mesh convergence depends on breaking the nonuniqueness with explicit use of the laminar Schmidt and Prandtl numbers and their turbulent counterparts, defined in terms of subgrid scale models. The dependence of the mixing rate on the Schmidt and Prandtl numbers and other physical parameters will be illustrated. We demonstrate numerically the influence of initial conditions on the mixing rate. Both the dominant short wavelength initial conditions and long wavelength perturbations are observed to play a role. By examination of two classes of experiments, we observe the absence of a single universal explanation, with long and short wavelength initial conditions, and the various physical and numerical regularizations contributing in different proportions in these two different contexts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930000205&hterms=density+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddensity%2Bair','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930000205&hterms=density+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddensity%2Bair"><span id="translatedtitle">Measuring Density Of Air By Ultraviolet <span class="hlt">Rayleigh</span> <span class="hlt">Scattering</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mckenzie, Robert L.</p> <p>1992-01-01</p> <p>Report presents theoretical and experimental studies directed toward development of optoelectronic instrument to measure density of air at altitudes from 50 to 90 km and possibly beyond. Instrument mounted in Space Shuttle orbiter and operated during reentry into atmosphere. Data gathered by instrument needed because density of upper atmosphere highly variable in space and time and this variability affects aerodynamic behavior and trajectory of reentering Shuttle. Variations in density also meteorologically significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960049948','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960049948"><span id="translatedtitle"><span class="hlt">Rayleigh</span> Light <span class="hlt">Scattering</span> for Concentration Measurements in Turbulent Flows</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pitts, William M.</p> <p>1996-01-01</p> <p>Despite intensive research over a number of years, an understanding of scalar mixing in turbulent flows remains elusive. An understanding is required because turbulent mixing has a pivotal role in a wide variety of natural and technologically important processes. As an example, the mixing and transport of pollutants in the atmosphere and in bodies of water are often dependent on turbulent mixing processes. Turbulent mixing is also central to turbulent combustion which underlies most hydrocarbon energy use in modern societies as well as in unwanted fire behavior. Development of models for combusting flows is therefore crucial, however, an understanding of scalar mixing is required before useful models of turbulent mixing and, ultimately, turbulent combustion can be developed. An important subset of turbulent flows is axisymmetric turbulent jets and plumes because they are relatively simple to generate, and because the provide an appropriate test bed for the development of general theories of turbulent mixing which can be applied to more complex geometries and flows. This paper focuses on a number of experimental techniques which have been developed at the National Institute of Standards and Development for measuring concentration in binary axisymmetric turbulent jets. In order to demonstrate the value of these diagnostics, some of the more important results from earlier and on-going investigations are summarized. Topics addressed include the similarity behavior of variable density axisymmetric jets, the behavior of absolutely unstable axisymmetric helium jets, and the role of large scale structures and scalar dissipation in these flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730036238&hterms=upward+transmission&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dupward%2Btransmission','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730036238&hterms=upward+transmission&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dupward%2Btransmission"><span id="translatedtitle">Matrix operator theory of radiative transfer. I - <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Plass, G. N.; Kattawar, G. W.; Catchings, F. E.</p> <p>1973-01-01</p> <p>An entirely rigorous method for the solution of the equations for radiative transfer based on the matrix operator theory is reviewed. The advantages of the present method are: (1) all orders of the reflection and transmission matrices are calculated at once; (2) layers of any thickness may be combined, so that a realistic model of the atmosphere can be developed from any arbitrary number of layers, each with different properties and thicknesses; (3) calculations can readily be made for large optical depths and with highly anisotropic phase functions; (4) results are obtained for any desired value of the surface albedo including the value unity and for a large number of polar and azimuthal angles; (5) all fundamental equations can be interpreted immediately in terms of the physical interactions appropriate to the problem; and (6) both upward and downward radiance can be calculated at interior points from relatively simple expressions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5913007','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5913007"><span id="translatedtitle">Overview of <span class="hlt">Rayleigh</span>-Taylor instability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sharp, D.H.</p> <p>1983-01-01</p> <p>The aim of this talk is to survey <span class="hlt">Rayleigh</span>-Taylor instability, describing the phenomenology that occurs at a Taylor unstable interface, and reviewing attempts to understand these phenomena quantitatively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARS23013M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARS23013M"><span id="translatedtitle"><span class="hlt">Rayleigh</span> surface waves, phonon mode conversion, and thermal transport in nanostructures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maurer, Leon; Knezevic, Irena</p> <p></p> <p>We study the effects of phonon mode conversion and <span class="hlt">Rayleigh</span> (surface) waves on thermal transport in nanostructures. We present a technique to calculate thermal conductivity in the elastic-solid approximation: a finite-difference time-domain (FDTD) solution of the elastic or scalar wave equations combined with the Green-Kubo formula. The technique is similar to an equilibrium molecular dynamics simulation, captures phonon wave behavior, and scales well to nanostructures that are too large to simulate with many other techniques. By imposing fixed or free boundary conditions, we can selectively turn off mode conversion and <span class="hlt">Rayleigh</span> waves to study their effects. In the example case of graphenelike nanoribbons with rough edges, we find that mode conversion among bulk modes has little effect on thermal transport, but that conversion between bulk and <span class="hlt">Rayleigh</span> waves can significantly reduce thermal conductivity. With increasing surface disorder, <span class="hlt">Rayleigh</span> waves readily become trapped by the disorder and draw energy away from the propagating bulk modes, which lowers thermal conductivity. We discuss the implications on the accuracy of popular phonon-surface <span class="hlt">scattering</span> models that stem from scalar wave equations and cannot capture mode conversion to <span class="hlt">Rayleigh</span> waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/40277874','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/40277874"><span id="translatedtitle"><span class="hlt">Rayleigh</span>--Taylor spike evaporation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schappert, G. T.; Batha, S. H.; Klare, K. A.; Hollowell, D. E.; Mason, R. J.</p> <p>2001-09-01</p> <p>Laser-based experiments have shown that <span class="hlt">Rayleigh</span>--Taylor (RT) growth in thin, perturbed copper foils leads to a phase dominated by narrow spikes between thin bubbles. These experiments were well modeled and diagnosed until this '' spike'' phase, but not into this spike phase. Experiments were designed, modeled, and performed on the OMEGA laser [T. R. Boehly, D. L. Brown, R. S. Craxton , Opt. Commun. 133, 495 (1997)] to study the late-time spike phase. To simulate the conditions and evolution of late time RT, a copper target was fabricated consisting of a series of thin ridges (spikes in cross section) 150 {mu}m apart on a thin flat copper backing. The target was placed on the side of a scale-1.2 hohlraum with the ridges pointing into the hohlraum, which was heated to 190 eV. Side-on radiography imaged the evolution of the ridges and flat copper backing into the typical RT bubble and spike structure including the '' mushroom-like feet'' on the tips of the spikes. RAGE computer models [R. M. Baltrusaitis, M. L. Gittings, R. P. Weaver, R. F. Benjamin, and J. M. Budzinski, Phys. Fluids 8, 2471 (1996)] show the formation of the '' mushrooms,'' as well as how the backing material converges to lengthen the spike. The computer predictions of evolving spike and bubble lengths match measurements fairly well for the thicker backing targets but not for the thinner backings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22j2707S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22j2707S"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor mixing in supernova experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swisher, N. C.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.; Abarzhi, S. I.</p> <p>2015-10-01</p> <p>We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced <span class="hlt">Rayleigh</span>-Taylor instability and <span class="hlt">Rayleigh</span>-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the <span class="hlt">Rayleigh</span>-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of <span class="hlt">Rayleigh</span>-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments <span class="hlt">Rayleigh</span>-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; <span class="hlt">Rayleigh</span>-Taylor mixing keeps order.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22486444','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22486444"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor mixing in supernova experiments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Swisher, N. C.; Abarzhi, S. I.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.</p> <p>2015-10-15</p> <p>We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced <span class="hlt">Rayleigh</span>-Taylor instability and <span class="hlt">Rayleigh</span>-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the <span class="hlt">Rayleigh</span>-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of <span class="hlt">Rayleigh</span>-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments <span class="hlt">Rayleigh</span>-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; <span class="hlt">Rayleigh</span>-Taylor mixing keeps order.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15765712','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15765712"><span id="translatedtitle">Ultraviolet <span class="hlt">Rayleigh</span>-Mie lidar for daytime-temperature profiling of the troposphere.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao</p> <p>2005-03-01</p> <p>A UV <span class="hlt">Rayleigh</span>-Mie <span class="hlt">scattering</span> lidar has been developed for daytime measurement of temperature and aerosol optical properties in the troposphere. The transmitter is a narrowband, injection-seeded, pulsed, third-harmonic Nd:YAG laser at an eye-safe wavelength of 355 nm. Two Fabry-Perot etalons (FPEs) with a dual-pass optical layout filter the molecular <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> components spectrally for retrieval of the temperature and provide a high rejection rate for aerosol Mie <span class="hlt">scattering</span> in excess of 43 dB. The Mie signal is filtered with a third FPE filter for direct profiling of aerosol optical properties. The Mie <span class="hlt">scattering</span> component in the <span class="hlt">Rayleigh</span> signals, which will have influence on temperature measurements, is corrected by using a measure of aerosol <span class="hlt">scattering</span> because of the relative insufficiency of Mie rejection of <span class="hlt">Rayleigh</span> filters in the presence of dense aerosols or clouds, and the Mie rejection capability of system is thus improved. A narrowband interference filter is incorporated with the FPEs to block solar radiation. Also, the small field of view (0.1 mrad) of the receiver and the UV wavelength used enhance the ability of the lidar to suppress the solar background signal in daytime measurement. The system is relatively compact, with a power-aperture product of 0.18 W m(-2), and has a high sensitivity to temperature change (0.62%/K). Lidar measurements taken under different weather conditions (winter and summer) are demonstrated. Good agreement between the lidar and the radiosonde measurements was obtained in terms of lapse rates and inversions. Statistical temperature errors of less than 1 K up to a height of 2 km are obtainable, with an averaging time of approximately 12 min for daytime measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15765712','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15765712"><span id="translatedtitle">Ultraviolet <span class="hlt">Rayleigh</span>-Mie lidar for daytime-temperature profiling of the troposphere.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hua, Dengxin; Uchida, Masaru; Kobayashi, Takao</p> <p>2005-03-01</p> <p>A UV <span class="hlt">Rayleigh</span>-Mie <span class="hlt">scattering</span> lidar has been developed for daytime measurement of temperature and aerosol optical properties in the troposphere. The transmitter is a narrowband, injection-seeded, pulsed, third-harmonic Nd:YAG laser at an eye-safe wavelength of 355 nm. Two Fabry-Perot etalons (FPEs) with a dual-pass optical layout filter the molecular <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> components spectrally for retrieval of the temperature and provide a high rejection rate for aerosol Mie <span class="hlt">scattering</span> in excess of 43 dB. The Mie signal is filtered with a third FPE filter for direct profiling of aerosol optical properties. The Mie <span class="hlt">scattering</span> component in the <span class="hlt">Rayleigh</span> signals, which will have influence on temperature measurements, is corrected by using a measure of aerosol <span class="hlt">scattering</span> because of the relative insufficiency of Mie rejection of <span class="hlt">Rayleigh</span> filters in the presence of dense aerosols or clouds, and the Mie rejection capability of system is thus improved. A narrowband interference filter is incorporated with the FPEs to block solar radiation. Also, the small field of view (0.1 mrad) of the receiver and the UV wavelength used enhance the ability of the lidar to suppress the solar background signal in daytime measurement. The system is relatively compact, with a power-aperture product of 0.18 W m(-2), and has a high sensitivity to temperature change (0.62%/K). Lidar measurements taken under different weather conditions (winter and summer) are demonstrated. Good agreement between the lidar and the radiosonde measurements was obtained in terms of lapse rates and inversions. Statistical temperature errors of less than 1 K up to a height of 2 km are obtainable, with an averaging time of approximately 12 min for daytime measurements. PMID:15765712</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5095505','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5095505"><span id="translatedtitle">On the linear instability of the <span class="hlt">Rayleigh</span> spheroidization process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hackney, S.A. . Dept. of Metallurgical Engineering)</p> <p>1991-01-01</p> <p>The problem of diffusional stability of infinitely long cylinders with respect to spheroidization has been analyzed. It is well known that long solid cylinders will break down into individual particles of spherical geometry under the action of an appropriate shape perturbation. The driving force for this process is considered to be the chemical potential gradients associated with variations in curvature which develop on the surface, or interface, in response to the perturbation. The resulting diffusional flow of material can lead to a breakdown of the rod morphology. From a practical point of view, the cylindrical geometry is one which occurs in fiber reinforced composites and rod shaped precipitates in eutectic/eutectoid structures. The shape stability of such rods is an important aspect of high temperature mechanical behavior. The general method of study for this problem involves analyzing the time dependent behavior of a perturbation; which is an imposed, mass conserving and periodic surface wave of small amplitude. These surface undulations will be referred to here as <span class="hlt">Rayleigh</span> surface waves. In most cases, attention is focused on the surface wavelength which gives the maximum growth rate of the perturbation. This choice has not been justified by experimental results on rod eutectics which show significant <span class="hlt">scatter</span> in the instability wavelength, and little or no physical basis, such as a stability argument, has been presented for the operation of the maximum growth rate hypothesis in the growth of periodic <span class="hlt">Rayleigh</span> surface waves. Despite the many detailed studies on the behavior of <span class="hlt">Rayleigh</span> surface waves, the possibility that the surface waves themselves might actually be unstable has not been considered in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/518351','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/518351"><span id="translatedtitle">Stimulated <span class="hlt">Rayleigh</span> resonances and recoil-induced effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Courtois, J.Y.; Grynberg, G.</p> <p>1996-12-31</p> <p>The organization of this paper is as follows. We present in Section II the basic ideas about stimulated <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> by considering more particularly the situation where it arises from a relaxation process going on in the material system, and we describe a few experimental observations made in atomic and molecular physics. We then consider the case of nonstationary two-level atoms, and we derive the shape and characteristics of the recoil-induced resonances (Section III). In particular, we show that these resonances can be interpreted either as originating from a stimulated <span class="hlt">Rayleigh</span> effect or as a stimulated Raman phenomena between atomic energy-momentum states having different momenta. Finally, to make a clear distinction between the physical phenomena that pertain directly to recoil-induced processes (i.e., that actually permit the measurement of the photon recoil) and those for which the introduction of the recoil constitutes a mere physical convenience, we review in Section IV some indisputable manifestations of the photon recoil in atomic and molecular physics. 92 refs., 22 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984PhRvA..30.2802S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984PhRvA..30.2802S"><span id="translatedtitle">Possibility of modification of the <span class="hlt">Rayleigh</span> line in a nonequilibrium fluid with a constant shear velocity gradient</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sahoo, Debendranath; Sood, A. K.</p> <p>1984-11-01</p> <p>We show that the recent prediction of the García-Colín and Velasco <article>[Phys. Rev. A 26 2187 (1982)]</article> regarding the modification of the <span class="hlt">Rayleigh</span> line, in the <span class="hlt">scattering</span> of light from a fluid kept under a constant shear veloity gradient, is incorrect. A correct application of fluctuating hydrodynamics is shown to predict no such change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730056627&hterms=tapping&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtapping','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730056627&hterms=tapping&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtapping"><span id="translatedtitle">On the surface-to-bulk mode conversion of <span class="hlt">Rayleigh</span> waves.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, C.-P.; Tuan, H.-S.</p> <p>1973-01-01</p> <p>Surface-to-bulk wave conversion phenomena occurring at a discontinuity characterized by a surface contour deformation are shown to be usable as a means for tapping <span class="hlt">Rayleigh</span> waves in a nonpiezoelectric solid. A boundary perturbation technique is used in the treatment of the mode conversion problem. A systematic procedure is presented for calculating not only the first-order <span class="hlt">scattered</span> waves, which include the reflected surface wave and the converted bulk wave, but also the higher order terms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhSen...6..209L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhSen...6..209L"><span id="translatedtitle">Study of <span class="hlt">Rayleigh</span>-backscattering induced coherence collapse in an asymmetric DFB FL sensor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Wen; Ma, Lina; Hu, Zhengliang; Feng, Ying; Yang, Huayong</p> <p>2016-09-01</p> <p><span class="hlt">Rayleigh</span>-back <span class="hlt">scattering</span> induced coherence collapse of an asymmetric distributed feedback fiber laser (DFB FL) sensor is investigated using a composite cavity model. The coherence collapse threshold condition of the asymmetric DFB FL sensor is measured. The DFB FL sensor shows different dynamic behaviors in different pump configurations. According to the asymmetric behavior to the external optical feedback, a novel method to find the actual phase shift position of the asymmetric DFB FL sensor is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890020559','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890020559"><span id="translatedtitle">Gravity wave climatology at midlatitude from <span class="hlt">Rayleigh</span> lidar data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, R.; Chanin, M. L.; Hauchecorne, A.</p> <p>1989-01-01</p> <p>Atmospheric sounding of the middle atmosphere by <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> has been performed in France for several years, from two stations with different orographic situations: one in the Alps, the Observatoire de Haute Provence, one on the Atlantic coast at Biscarosse. The vertical profiles of density and temperature are obtained with a temporal and spatial resolution of, respectively, 15 mn and 300 m between 30 and 80 km. A statistical study of the atmospheric fluctuations due to gravity waves was performed and the main results are presented: climatology of the gravity wave activity, distribution of energy versus vertical wave number and altitude, and comparison of the observations at the two sites. Conclusions are presented on the saturation of the wave field, the filtering by the mean wind, the transfer of energy and momentum into the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHEP...11..036B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHEP...11..036B"><span id="translatedtitle">Chromo-<span class="hlt">Rayleigh</span> interactions of dark matter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bai, Yang; Osborne, James</p> <p>2015-11-01</p> <p>For a wide range of models, dark matter can interact with QCD gluons via chromo-<span class="hlt">Rayleigh</span> interactions. We point out that the Large Hadron Collider (LHC), as a gluon machine, provides a superb probe of such interactions. In this paper, we introduce simplified models to UV-complete two effective dark matter chromo-<span class="hlt">Rayleigh</span> interactions and identify the corresponding collider signatures, including four jets or a pair of di-jet resonances plus missing transverse energy. After performing collider studies for both the 8 TeV and 14 TeV LHC, we find that the LHC can be more sensitive to dark matter chromo-<span class="hlt">Rayleigh</span> interactions than direct detection experiments and thus provides the best opportunity for future discovery of this class of models.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......284A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......284A"><span id="translatedtitle">The <span class="hlt">Rayleigh</span> ratio measurement for SNO+ liquid scintillator and background studies of the internal ropes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asahi, Satoko</p> <p></p> <p>As a successor of the Sudbury Neutrino Observatory, the SNO+ experiment is planned to start data taking in early 2013. Making use of the liquid scintillator, Linear Alkylbenzene (LAB), the SNO+ experiment aims to perform flux measurements of low energy solar neutrinos in one phase, and wait for neutrinoless double beta decay events in another phase where 44 kg of natural Neodymium would be added into LAB. The <span class="hlt">Rayleigh</span> ratio of LAB was found to be 16.60 +/- 3.14 x 10--6 cm--1 at 546 nm using the relative measurement technique. The wavelength dependency of the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> was also examined and compared with the theoretical prediction. A setup which is usable to measure the angular dependency of the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> was built, and an isotropic behaviour of the <span class="hlt">scattering</span> was tested. The beta and gamma backgrounds, due to the internal calibration ropes situated in the scintillator volume, were studied using the SNO+ Monte Carlo Package. Also, the amount of 210Pb originating from the internal calibration ropes due to the intrinsic contamination of 238U, Rn emanation and plated on the surface prior to the installation were assessed to examine if it is a tolerable level to achieve the target level of 13.4 background events per day.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3715...60J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3715...60J"><span id="translatedtitle">Optical results with <span class="hlt">Rayleigh</span> quotient discrimination filters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Juday, Richard D.; Rollins, John M.; Monroe, Stanley E., Jr.; Morelli, Michael V.</p> <p>1999-03-01</p> <p>We report experimental laboratory results using filters that optimize the <span class="hlt">Rayleigh</span> quotient [Richard D. Juday, 'Generalized <span class="hlt">Rayleigh</span> quotient approach to filter optimization,' JOSA-A 15(4), 777-790 (April 1998)] for discriminating between two similar objects. That quotient is the ratio of the correlation responses to two differing objects. In distinction from previous optical processing methods it includes the phase of both objects -- not the phase of only the 'accept' object -- in the computation of the filter. In distinction from digital methods it is explicitly constrained to optically realizable filter values throughout the optimization process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750021532','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750021532"><span id="translatedtitle">Multiple <span class="hlt">scattered</span> radiation emerging from continental haze layers. 1: Radiance, polarization, and neutral points</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kattawar, G. W.; Plass, G. N.; Hitzfelder, S. J.</p> <p>1975-01-01</p> <p>The complete radiation field is calculated for <span class="hlt">scattering</span> layers of various optical thicknesses. Results obtained for <span class="hlt">Rayleigh</span> and haze <span class="hlt">scattering</span> are compared. Calculated radiances show differences as large as 23% compared to the approximate scalar theory of radiative transfer, while the same differences are approximately 0.1% for a continental haze phase function. The polarization of reflected and transmitted radiation is given for various optical thicknesses, solar zenith angles, and surface albedos. Two types of neutral points occur for aerosol phase functions. <span class="hlt">Rayleigh</span>-like neutral points arise from zero polarization that occurs at <span class="hlt">scattering</span> angles of 0 deg and 180 deg. For <span class="hlt">Rayleigh</span> phase functions, the position of these points varies with the optical thickness of the <span class="hlt">scattering</span> layer. Non-<span class="hlt">Rayleigh</span> neutral points are associated with the zeros of polarization which occur between the end points of the single <span class="hlt">scattering</span> curve, and are found over a wide range of azimuthal angles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JPhCS.454a2033N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JPhCS.454a2033N"><span id="translatedtitle">Validity of the <span class="hlt">Rayleigh</span> hypothesis for two-dimensional randomly rough metal surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nordam, T.; Letnes, P. A.; Simonsen, I.</p> <p>2013-08-01</p> <p>The <span class="hlt">Rayleigh</span> hypothesis is the assumption that the field in the region above (below) a rough surface can be expressed as a weighted sum of upwards (downwards) propagating <span class="hlt">scattered</span> (transmitted) modes, and that these expressions can be used to satisfy the boundary conditions on the fields at the surface. This hypothesis is expected to be valid for surfaces of sufficiently small slopes. For one-dimensional sinusoidal surfaces, the region of validity is known analytically, while for randomly rough surfaces in one and two dimensions, the limits of validity of the <span class="hlt">Rayleigh</span> hypothesis are not known. In this paper, we perform a numerical study of the validity of the <span class="hlt">Rayleigh</span> hypothesis for two-dimensionally rough metal and perfectly conducting surfaces by considering the conservation of energy. It is found for a perfect electric conductor that the region of validity is defined by the ratio of the root-mean-square roughness, δ, over the correlation length, α, being less than about 0.2, while for silver we find δ/α lesssim 0.08 for an incident wavelength λ = 457.9 nm. Limitations in our simulations made us unable to check the <span class="hlt">Rayleigh</span> hypothesis for roughness where δ gtrsim 0.13λ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930008806','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930008806"><span id="translatedtitle">Laser <span class="hlt">Rayleigh</span> and Raman Diagnostics for Small Hydrogen/oxygen Rockets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Degroot, Wilhelmus A.; Zupanc, Frank J.</p> <p>1993-01-01</p> <p>Localized velocity, temperature, and species concentration measurements in rocket flow fields are needed to evaluate predictive computational fluid dynamics (CFD) codes and identify causes of poor rocket performance. Velocity, temperature, and total number density information have been successfully extracted from spectrally resolved <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in the plume of small hydrogen/oxygen rockets. Light from a narrow band laser is <span class="hlt">scattered</span> from the moving molecules with a Doppler shifted frequency. Two components of the velocity can be extracted by observing the <span class="hlt">scattered</span> light from two directions. Thermal broadening of the <span class="hlt">scattered</span> light provides a measure of the temperature, while the integrated <span class="hlt">scattering</span> intensity is proportional to the number density. Spontaneous Raman <span class="hlt">scattering</span> has been used to measure temperature and species concentration in similar plumes. Light from a dye laser is <span class="hlt">scattered</span> by molecules in the rocket plume. Raman spectra <span class="hlt">scattered</span> from major species are resolved by observing the inelastically <span class="hlt">scattered</span> light with linear array mounted to a spectrometer. Temperature and oxygen concentrations have been extracted by fitting a model function to the measured Raman spectrum. Results of measurements on small rockets mounted inside a high altitude chamber using both diagnostic techniques are reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSM.U22A..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSM.U22A..05M"><span id="translatedtitle">Multiphase <span class="hlt">Rayleigh</span> Fractionation Redux and the Laramie-Kiglapait Connection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morse, S. A.; Scoates, J. S.; Lindsley, D. H.</p> <p>2006-05-01</p> <p>Three distinct paths occur in multicomponent <span class="hlt">Rayleigh</span> fractionation, two as limits and the third as a resultant. The limiting DEPLETION effect, brought to our attention by Paul Asimow, causes a rapid evolution of a binary solution by itself in the presence of another component, as the quantity of liquid remains high when a second phase fails to crystallize. The limiting EXTENDED COTECTIC effect occurs when the crystallizing region is re- supplied from an infinite reservoir within the magma chamber. The resultant of the two is exactly equal to fractionation on the PURE BINARY. The MELTS algorithm recognizes the depletion effect and a cotectic that lies on the binary. Multiphase <span class="hlt">Rayleigh</span> fractionation (MRF; Morse 2005, ChemGeo 226/3-4:212) recognizes the extended cotectic effect. Natural cotectic systems tend to occupy the entire region from the binary to the extended cotectic. Experimental fractionation mimics the infinite reservoir effect and closely matches the evolution of plagioclase and olivine in the Kiglapait Intrusion (KI). MRF describes the evolution of binary solutions taken one at a time in cotectic systems. It is aided by the linear partitioning principle D = KD*X2S +X1S, where D is the partition coefficient X1S/X1L, X is the mole (mass, atom) fraction, S and L are solid and liquid, and the exchange coefficient KD is the intercept of D at pure (2), from which D runs to 1.0 at pure (1); (Morse, 2000 GCA 64:2309). Stepwise fractionation calculations describe the evolution of D, X1L = C, and Co in the <span class="hlt">Rayleigh</span> equation C=CoF(L)(D-1), where the fraction of liquid remaining, F(L), is the leading variable. The two limiting paths of fractionation are found by applying an operator, the fraction f(alpha) of the active phase, to the <span class="hlt">Rayleigh</span> exponent (D-1). The depletion path is generated by (D-1)/f(alpha); the extended cotectic path is generated by f(alpha)(D-1), and the cotectic path is generated by both together, hence f(alpha)(D- 1)/f(alpha) = (D-1), which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21544813','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21544813"><span id="translatedtitle">Doppler optical mixing spectroscopy in multiparticle <span class="hlt">scattering</span> fluids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dubnishchev, Yu N</p> <p>2011-03-31</p> <p>We discuss the basic scheme of laser Doppler optical mixing spectroscopy for the analysis of media with multiparticle <span class="hlt">scattering</span>. It is shown that the <span class="hlt">Rayleigh</span> scheme, in contrast to the heterodyne and differential schemes, is insensitive to the effects of multiparticle <span class="hlt">scattering</span>. (laser applications and other aspects of quantum electronics)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16270544','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16270544"><span id="translatedtitle">Use of <span class="hlt">Rayleigh</span> imaging and ray tracing to correct for beam-steering effects in turbulent flames.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaiser, Sebastian A; Frank, Jonathan H; Long, Marshall B</p> <p>2005-11-01</p> <p>Laser <span class="hlt">Rayleigh</span> imaging has been applied in a number of flow and flame studies to measure concentration or temperature distributions. <span class="hlt">Rayleigh</span> cross sections are dependent on the index of refraction of the <span class="hlt">scattering</span> medium. The same index of refraction changes that provide contrast in <span class="hlt">Rayleigh</span> images can also deflect the illuminating laser sheet. By applying a ray-tracing algorithm to the detected image, it is possible to correct for some of these beam-steering effects and thereby improve the accuracy of the measured field. Additionally, the quantification of the degree of beam steering through the flow provides information on the degradation of spatial resolution in the measurement. Application of the technique in a well-studied laboratory flame is presented, along with analysis of the effects of image noise and spatial resolution on the effectiveness of the algorithm. PMID:16270544</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22311425','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22311425"><span id="translatedtitle">Experimental confirmation of neoclassical Compton <span class="hlt">scattering</span> theory</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aristov, V. V.; Yakunin, S. N.; Despotuli, A. A.</p> <p>2013-12-15</p> <p>Incoherent X-ray <span class="hlt">scattering</span> spectra of diamond and silicon crystals recorded on the BESSY-2 electron storage ring have been analyzed. All spectral features are described well in terms of the neoclassical <span class="hlt">scattering</span> theory without consideration for the hypotheses accepted in quantum electrodynamics. It is noted that the accepted tabular data on the intensity ratio between the Compton and <span class="hlt">Rayleigh</span> spectral components may significantly differ from the experimental values. It is concluded that the development of the general theory (considering coherent <span class="hlt">scattering</span>, incoherent <span class="hlt">scattering</span>, and Bragg diffraction) must be continued.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70037250','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70037250"><span id="translatedtitle">High-frequency <span class="hlt">Rayleigh</span>-wave method</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xia, J.; Miller, R.D.; Xu, Y.; Luo, Y.; Chen, C.; Liu, J.; Ivanov, J.; Zeng, C.</p> <p>2009-01-01</p> <p>High-frequency (???2 Hz) <span class="hlt">Rayleigh</span>-wave data acquired with a multichannel recording system have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave techniques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a non-invasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of <span class="hlt">Rayleigh</span> waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency <span class="hlt">Rayleigh</span>-waves in near-surface media, which builds a foundation for shallow seismic or <span class="hlt">Rayleigh</span>-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OptCo.317...13P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OptCo.317...13P"><span id="translatedtitle">Low <span class="hlt">scattering</span> loss fiber with segmented-core and depressed inner cladding structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pournoury, Marzieh; Moon, Dae Seung; Nazari, Tavakol; Kassani, Sahar Hosseinzadeh; Do, Mun-Hyun; Lee, Yeong Seop; Oh, Kyunghwan</p> <p>2014-04-01</p> <p>In this paper, using the FEM method new low-loss fiber is proposed to minimize <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> with a segmented-core and depressed inner-cladding. The optical loss of the designed fiber is calculated based on <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> losses. <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> loss (RSL) has been estimated by <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> coefficient (RSC) and power distribution in the fiber. We have shown loss of less than 0.3 dB/km at 1310 nm, 0.18 dB/km at 1550 nm for step-index fibers which consist of conventional glass compositions such as SiO2, GeO2-SiO2, F-SiO2 while satisfying all of ITU-G.652.D attributes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/264007','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/264007"><span id="translatedtitle">Evaluation of surface fatigue cracks using <span class="hlt">Rayleigh</span> waves. Ph.D. Thesis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cheng, A.</p> <p>1994-01-01</p> <p>An acoustic <span class="hlt">scattering</span> model for a planar distribution of cracks in an infinite space is derived based on the generalized reciprocity and Kino`s <span class="hlt">scattering</span> formalism. Subsequently, an acoustic <span class="hlt">scattering</span> model of <span class="hlt">Rayleigh</span> waves for a linear distribution of surface cracks in a half space in the form of the local stress intensity factor of the surface cracks is developed by using the elastostatic energy balance of crack formation. The weight function estimation method is introduced into the <span class="hlt">scattering</span> model to approximately evaluate the local stress intensity factor of the crack in the stress fields of <span class="hlt">Rayleigh</span> waves to improve the evaluation results and to extend the maximum crack depth region which can be evaluated. The initiation and growth behavior of the surface cracks which are related with the reflection coefficient are studied by evaluating the reflection coefficient varying with respect to: crack aspect ratios, frequencies, and the number of cracks for several aerospace materials such as Al 7075 T6, Al-Li 2090 T6, Ti-24Al-11Nb and Ti 6Al-4V. The results show that by using the newly developed model not only the evaluation of the reflection coefficient of <span class="hlt">Rayleigh</span> waves for a linear distribution of surface cracks become possible but also the evaluation results are improved. Contacting surface acoustic wave wedge transducers are optimally designed and fabricated using principles of physical acoustics, and the impedance matching networks are introduced to increase the efficiency of the transducer. The new transducers used in combination with the variable impedance matching networks increase the efficiency of SAW devices produced by a factor of five. An automated detection system including the control software is developed. Isolated surface fatigue microcracks in the size range from 120 to 135 micron are detected on hourglass shaped laboratory test specimens of Al-Li 2090 using the detection system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18301575','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18301575"><span id="translatedtitle">Single <span class="hlt">scattering</span> by red blood cells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hammer, M; Schweitzer, D; Michel, B; Thamm, E; Kolb, A</p> <p>1998-11-01</p> <p>A highly diluted suspension of red blood cells (hematocrit 0.01) was illuminated with an Ar or a dye laser in the wavelength range of 458-660 nm. The extinction and the angle-resolved intensity of <span class="hlt">scattered</span> light were measured and compared with the predictions of Mie theory, the <span class="hlt">Rayleigh</span>-Gans approximation, and the anomalous diffraction approximation. Furthermore, empirical phase functions were fitted to the measurements. The measurements were in satisfactory agreement with the predictions of Mie theory. However, better agreement was found with the anomalous diffraction model. In the <span class="hlt">Rayleigh</span>-Gans approximation, only small-angle <span class="hlt">scattering</span> is described appropriately. The <span class="hlt">scattering</span> phase function of erythrocytes may be represented by the Gegenbauer kernel phase function. PMID:18301575</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720055949&hterms=1088&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231088','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720055949&hterms=1088&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231088"><span id="translatedtitle"><span class="hlt">Rayleigh</span> wave effects in an elastic half-space.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aggarwal, H. R.</p> <p>1972-01-01</p> <p>Consideration of <span class="hlt">Rayleigh</span> wave effects in a homogeneous isotropic linearly elastic half-space subject to an impulsive uniform disk pressure loading. An approximate formula is obtained for the <span class="hlt">Rayleigh</span> wave effects. It is shown that the <span class="hlt">Rayleigh</span> waves near the center of loading arise from the portion of the dilatational and shear waves moving toward the axis, after they originate at the edge of the load disk. A study is made of the vertical displacement due to <span class="hlt">Rayleigh</span> waves at points on the axis near the surface of the elastic half-space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24950635','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24950635"><span id="translatedtitle">Gaining improved chemical composition by exploitation of Compton-to-<span class="hlt">Rayleigh</span> intensity ratio in XRF analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hodoroaba, Vasile-Dan; Rackwitz, Vanessa</p> <p>2014-07-15</p> <p>The high specificity of the coherent (<span class="hlt">Rayleigh</span>), as well as incoherent (Compton) X-ray <span class="hlt">scattering</span> to the mean atomic number of a specimen to be analyzed by X-ray fluorescence (XRF), is exploited to gain more information on the chemical composition. Concretely, the evaluation of the Compton-to-<span class="hlt">Rayleigh</span> intensity ratio from XRF spectra and its relation to the average atomic number of reference materials via a calibration curve can reveal valuable information on the elemental composition complementary to that obtained from the reference-free XRF analysis. Particularly for matrices of lower mean atomic numbers, the sensitivity of the approach is so high that it can be easily distinguished between specimens of mean atomic numbers differing from each other by 0.1. Hence, the content of light elements which are "invisible" for XRF, particularly hydrogen, or of heavier impurities/additives in light materials can be calculated "by difference" from the <span class="hlt">scattering</span> calibration curve. The excellent agreement between such an experimental, empirical calibration curve and a synthetically generated one, on the basis of a reliable physical model for the X-ray <span class="hlt">scattering</span>, is also demonstrated. Thus, the feasibility of the approach for given experimental conditions and particular analytical questions can be tested prior to experiments with reference materials. For the present work a microfocus X-ray source attached on an SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectroscopy) system was used so that the Compton-to-<span class="hlt">Rayleigh</span> intensity ratio could be acquired with EDX spectral data for improved analysis of the elemental composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.206..241B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.206..241B"><span id="translatedtitle">Imaging <span class="hlt">Rayleigh</span> wave attenuation with USArray</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bao, Xueyang; Dalton, Colleen A.; Jin, Ge; Gaherty, James B.; Shen, Yang</p> <p>2016-07-01</p> <p>The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity and provide important constraints on the temperature, composition, melt content, and volatile content of the mantle. The surface wave amplitudes that constrain upper-mantle attenuation are sensitive to factors in addition to attenuation, including the earthquake source excitation, focusing and defocusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, <span class="hlt">Rayleigh</span> wave traveltime and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique, which takes advantage of waveform similarity at nearby stations. Several estimates of <span class="hlt">Rayleigh</span> wave attenuation and site amplification are generated at each period, using different approaches to separate the effects of attenuation and local site amplification on amplitude. It is assumed that focusing and defocusing effects can be described by the Laplacian of the traveltime field. All approaches identify the same large-scale patterns in attenuation, including areas where the attenuation values are likely contaminated by unmodelled focusing and defocusing effects. Regionally averaged attenuation maps are constructed after removal of the contaminated attenuation values, and the variations in intrinsic shear attenuation that are suggested by these <span class="hlt">Rayleigh</span> wave attenuation maps are explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21408874','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21408874"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability in binary condensates</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gautam, S.; Angom, D.</p> <p>2010-05-15</p> <p>We propose a well-controlled experimental scheme to initiate and examine the <span class="hlt">Rayleigh</span>-Taylor instability in two-species Bose-Einstein condensates. We identify the {sup 85}Rb-{sup 87}Rb mixture as an excellent candidate to observe experimentally. The instability is initiated by tuning the {sup 85}Rb-{sup 85}Rb interaction through a magnetic Feshbach resonance. We show that the observable signature of the instability is the damping of the radial oscillations. We also propose a semianalytic scheme to determine the stationary state of binary condensates with the Thomas-Fermi approximation for axisymmetric traps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhA...49p5202C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhA...49p5202C"><span id="translatedtitle">Global study of <span class="hlt">Rayleigh</span>-Duffing oscillators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Hebai; Zou, Lan</p> <p>2016-04-01</p> <p>In this paper we investigate the global dynamics of <span class="hlt">Rayleigh</span>-Duffing oscillators with global parameters, including equilibria at both finity and infinity, existences and coexistence of limit cycles and homoclinic loops. In fact, this oscillator will occur Hopf bifurcations, homoclinic bifurcations and double limit cycle bifurcations. Moreover, we find that the homoclinic bifurcation of this oscillator is special which is a gluing bifurcation. The global bifurcation diagram and all phase portrait are given, and numerical simulations are shown to verify our analysis finally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16876218','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16876218"><span id="translatedtitle">Leaky <span class="hlt">Rayleigh</span> wave investigation on mortar samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Neuenschwander, J; Schmidt, Th; Lüthi, Th; Romer, M</p> <p>2006-12-01</p> <p>Aggressive mineralized ground water may harm the concrete cover of tunnels and other underground constructions. Within a current research project mortar samples are used to study the effects of sulfate interaction in accelerated laboratory experiments. A nondestructive test method based on ultrasonic surface waves was developed to investigate the topmost layer of mortar samples. A pitch and catch arrangement is introduced for the generation and reception of leaky <span class="hlt">Rayleigh</span> waves in an immersion technique allowing the measurement of their propagation velocity. The technique has been successfully verified for the reference materials aluminium, copper, and stainless steel. First measurements performed on mortar specimens demonstrate the applicability of this new diagnostic tool.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JSV...333..520H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JSV...333..520H"><span id="translatedtitle">Vibrational energy flow models for the <span class="hlt">Rayleigh</span>-Love and <span class="hlt">Rayleigh</span>-Bishop rods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Ju-Bum; Hong, Suk-Yoon; Song, Jee-Hun; Kwon, Hyun-Wung</p> <p>2014-01-01</p> <p>Energy Flow Analysis (EFA) has been developed to predict the vibrational energy density of the system structures in the medium-to-high frequency range. The elementary longitudinal wave theory is often used to describe the longitudinal vibration of a slender rod. However, for relatively large diameter rods or high frequency ranges, the elementary longitudinal wave theory is inaccurate because the lateral motions are not taken into account. In this paper, vibrational energy flow models are developed to analyze the longitudinally vibrating <span class="hlt">Rayleigh</span>-Love rod considering the effect of lateral inertia, and the <span class="hlt">Rayleigh</span>-Bishop rod considering the effect not only of the lateral inertia but also of the shear stiffness. The derived energy governing equations are second-order differential equations which predict the time and space averaged energy density and active intensity distributions in a rod. To verify the accuracy of the developed energy flow models, various numerical analyses are performed for a rod and coupled rods. Also, the EFA results for the <span class="hlt">Rayleigh</span>-Love and <span class="hlt">Rayleigh</span>-Bishop rods are compared with the analytical solutions for these models, the traditional energy flow solutions, and the analytical solutions for the classical rod.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvL.108y5006M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvL.108y5006M"><span id="translatedtitle">First Measurements of <span class="hlt">Rayleigh</span>-Taylor-Induced Magnetic Fields in Laser-Produced Plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manuel, M. J.-E.; Li, C. K.; Séguin, F. H.; Frenje, J.; Casey, D. T.; Petrasso, R. D.; Hu, S. X.; Betti, R.; Hager, J. D.; Meyerhofer, D. D.; Smalyuk, V. A.</p> <p>2012-06-01</p> <p>The first experimental demonstration of <span class="hlt">Rayleigh</span>-Taylor-induced magnetic fields due to the Biermann battery effect has been made. Experiments with laser-irradiated plastic foils were performed to investigate these illusive fields using a monoenergetic proton radiography system. Path-integrated B field strength measurements were inferred from radiographs and found to increase from 10 to 100Tμm during the linear growth phase for 120μm perturbations. Proton fluence modulations were corrected for Coulomb <span class="hlt">scattering</span> using measured areal density profiles from x-ray radiographs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/383891','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/383891"><span id="translatedtitle">Theory of the Anomalous <span class="hlt">Rayleigh</span> Dispersion at H/W(110) Surfaces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bungaro, C.; de Gironcoli, S.; Baroni, S. |</p> <p>1996-09-01</p> <p>The nature of the anomalies observed in the helium-atom <span class="hlt">scattering</span> (HAS) and electron energy-loss (EELS) spectra of hydrogenated W(110) surfaces is investigated by calculating the full dispersion of the <span class="hlt">Rayleigh</span> mode, using density-functional perturbation theory. We find excellent agreement between our calculations and the upper anomalous branch which is observed with both HAS and EELS. The lower branch{emdash}which is only detected by HAS{emdash}is instead not predicted. A hitherto unrecognized mechanism possibly responsible for the appearance of the second branch is proposed. {copyright} {ital 1996 The American Physical Society.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25607971','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25607971"><span id="translatedtitle"><span class="hlt">Rayleigh</span> beacon for measuring the surface profile of a radio telescope.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Padin, S</p> <p>2014-12-01</p> <p>Millimeter-wavelength <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3  mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned anywhere in the sky, as long as there are clouds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25607971','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25607971"><span id="translatedtitle"><span class="hlt">Rayleigh</span> beacon for measuring the surface profile of a radio telescope.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Padin, S</p> <p>2014-12-01</p> <p>Millimeter-wavelength <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3  mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned anywhere in the sky, as long as there are clouds. PMID:25607971</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/820806','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/820806"><span id="translatedtitle">Investigation of the <span class="hlt">Rayleigh</span>-Taylor and Richtmyer-Meshkov instabilities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Riccardo Bonazza; Mark Anderson; Leslie Smith</p> <p>2004-01-14</p> <p>Some of the major difficulties encountered in the effort to achieve nuclear fusion by means of inertial confinement arise from the unstable behavior of the interface between the shell material and the nuclear fuel which develops upon implosion of the shell by direct or indirect laser drive. The fluid flows that develop (termed the <span class="hlt">Rayleigh</span>-Taylor (RT) and the Richtmyer-Meshkov (RM) instabilities) cause the gassified shell material to mix with the nuclear fuel, causing a reduction in energy yield or no ignition altogether. The present research program addresses the <span class="hlt">Rayleigh</span>-Taylor and the Richtmyer-Meshkov instabilities with extensive laboratory and computational experiments. In the past year, three new activities have been initiated: a new shock tube experiment, involving the impulsive acceleration of a test gas-filled soap bubble, diagnosed with planar Mie <span class="hlt">scattering</span> or planar induced fluorescence; a <span class="hlt">Rayleigh</span>-Taylor experiment based on the use of a magnetorheological (MR) fluid to fix the initial shape of the interface between the MR fluid and water; and a series of computer calculations using the Raptor code (made available by Lawrence Livermore National Laboratory) to design and simulate the shock tube experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25321553','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25321553"><span id="translatedtitle">Stratospheric temperature measurement with scanning Fabry-Perot interferometer for wind retrieval from mobile <span class="hlt">Rayleigh</span> Doppler lidar.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xia, Haiyun; Dou, Xiankang; Shangguan, Mingjia; Zhao, Ruocan; Sun, Dongsong; Wang, Chong; Qiu, Jiawei; Shu, Zhifeng; Xue, Xianghui; Han, Yuli; Han, Yan</p> <p>2014-09-01</p> <p>Temperature detection remains challenging in the low stratosphere, where the <span class="hlt">Rayleigh</span> integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low <span class="hlt">scattering</span> cross section. To correct the impacts of temperature on the <span class="hlt">Rayleigh</span> Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and <span class="hlt">Rayleigh</span> integration techniques is incorporated into the <span class="hlt">Rayleigh</span> Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the <span class="hlt">Rayleigh</span> Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and <span class="hlt">Rayleigh</span> integration lidar from 27 km to 34 km. PMID:25321553</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25321553','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25321553"><span id="translatedtitle">Stratospheric temperature measurement with scanning Fabry-Perot interferometer for wind retrieval from mobile <span class="hlt">Rayleigh</span> Doppler lidar.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xia, Haiyun; Dou, Xiankang; Shangguan, Mingjia; Zhao, Ruocan; Sun, Dongsong; Wang, Chong; Qiu, Jiawei; Shu, Zhifeng; Xue, Xianghui; Han, Yuli; Han, Yan</p> <p>2014-09-01</p> <p>Temperature detection remains challenging in the low stratosphere, where the <span class="hlt">Rayleigh</span> integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low <span class="hlt">scattering</span> cross section. To correct the impacts of temperature on the <span class="hlt">Rayleigh</span> Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and <span class="hlt">Rayleigh</span> integration techniques is incorporated into the <span class="hlt">Rayleigh</span> Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the <span class="hlt">Rayleigh</span> Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and <span class="hlt">Rayleigh</span> integration lidar from 27 km to 34 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.206.1179L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.206.1179L"><span id="translatedtitle">On <span class="hlt">Rayleigh</span> wave in half-space: an asymptotic approach to study the <span class="hlt">Rayleigh</span> function and its relation to the <span class="hlt">Rayleigh</span> wave</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Tianshi; Feng, Xi; Zhang, Haiming</p> <p>2016-08-01</p> <p>To obtain the synthetic seismogram using the Cagniard-de Hoop method, one needs to calculate the integral over slowness. When the source is shallow and the slowness is near the zero of the <span class="hlt">Rayleigh</span> function, the integrand behaves like a sharp pulse. In this study, we attempt to study this pulse with an asymptotic approach, and conclude that the <span class="hlt">Rayleigh</span> wave in the time domain originates from this pulse in the slowness domain. We therefore offer an explanation of the excitation of the <span class="hlt">Rayleigh</span> wave in a mathematical point of view. In addition, we propose a method to improve the efficiency of the numerical quadrature in the calculation of the synthetic seismogram.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9205E..0IH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9205E..0IH"><span id="translatedtitle">Modeling stray light from rough surfaces and subsurface <span class="hlt">scatter</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harvey, James E.; Goshy, John J.; Pfisterer, Richard N.</p> <p>2014-09-01</p> <p>Over the years we have developed an adequate theory and understanding of surface <span class="hlt">scatter</span> from smooth optical surfaces (<span class="hlt">Rayleigh</span>-Rice), moderately rough surfaces with paraxial incident and <span class="hlt">scattered</span> angles (Beckmann- Kirchhoff) and even for moderately rough surfaces with arbitrary incident and <span class="hlt">scattered</span> angles where a linear systems formulation requiring a two-parameter family of surface transfer functions is required to characterize the surface <span class="hlt">scatter</span> process (generalized Harvey-Shack). However, there is always some new material or surface manufacturing process that provides non-intuitive <span class="hlt">scatter</span> behavior. The linear systems formulation of surface <span class="hlt">scatter</span> is potentially useful even for these situations. In this paper we will present empirical models of several classes of rough surfaces or materials (subsurface <span class="hlt">scatter</span>) that allow us to accurately model the <span class="hlt">scattering</span> behavior at any incident angle from limited measured <span class="hlt">scatter</span> data. In particular, <span class="hlt">scattered</span> radiance appears to continue being the natural quantity that exhibits simple, elegant behavior only in direction cosine space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982JGR....8710514S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982JGR....8710514S"><span id="translatedtitle">Role of <span class="hlt">Rayleigh</span>-Taylor instabilities on prompt striation evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sperling, J. L.</p> <p>1982-12-01</p> <p>It is suggested that a <span class="hlt">Rayleigh</span>-Taylor instability driven by ion inertia is a source of additional growth for prompt striations following the saturation of the seed, kinetic, loss cone instability. The destabilization of <span class="hlt">Rayleigh</span>-Taylor modes on the prompt striation scale size is seen as implying a simultaneous excitation of large scale size <span class="hlt">Rayleigh</span>-Taylor modes. The long-term influence of prompt striations on large scale fluid turbulence and on the outer scale of the power spectral density may be minimal. The kinetic loss cone and <span class="hlt">Rayleigh</span>-Taylor instabilities are treated in an asymptotic sense, with the kinetic loss cone instability being driven by an ion loss cone distribution function and possibly a density gradient and the <span class="hlt">Rayleigh</span>-Taylor instability (the result of a simultaneous density gradient and an electric polarization drift).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22489657','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489657"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-type parametric chemical oscillation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ghosh, Shyamolina; Ray, Deb Shankar</p> <p>2015-09-28</p> <p>We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained <span class="hlt">Rayleigh</span>-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JChPh.143l4901G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JChPh.143l4901G"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-type parametric chemical oscillation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghosh, Shyamolina; Ray, Deb Shankar</p> <p>2015-09-01</p> <p>We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained <span class="hlt">Rayleigh</span>-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyS...91g4004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyS...91g4004S"><span id="translatedtitle">Anelastic <span class="hlt">Rayleigh</span>-Taylor mixing layers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schneider, N.; Gauthier, S.</p> <p>2016-07-01</p> <p>Anelastic <span class="hlt">Rayleigh</span>-Taylor mixing layers for miscible fluids are investigated with a recently built model (Schneider and Gauthier 2015 J. Eng. Math. 92 55-71). Four Chebyshev-Fourier-Fourier direct numerical simulations are analyzed. They use different values for the compressibility parameters: Atwood number (the dimensionless difference of the heavy and light fluid densities) and stratification (accounts for the vertical variation of density due to gravity). For intermediate Atwood numbers and finite stratification, compressibility effects quickly occurs. As a result only nonlinear behaviours are reached. The influence of the compressibility parameters on the growth speed of the RTI is discussed. The 0.1—Atwood number/0.4—stratification configuration reaches a turbulent regime. This turbulent mixing layer is analyzed with statistical tools such as moments, PDFs, anisotropy indicators and spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26429035','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26429035"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-type parametric chemical oscillation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ghosh, Shyamolina; Ray, Deb Shankar</p> <p>2015-09-28</p> <p>We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained <span class="hlt">Rayleigh</span>-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26429035','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26429035"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-type parametric chemical oscillation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ghosh, Shyamolina; Ray, Deb Shankar</p> <p>2015-09-28</p> <p>We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained <span class="hlt">Rayleigh</span>-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions. PMID:26429035</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/102369','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/102369"><span id="translatedtitle">Classical <span class="hlt">Rayleigh</span> Taylor experiments on Nova</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Budil, K.S.; Remington, B.A.; Peyser, T.A.</p> <p>1995-07-01</p> <p>The evolution of the <span class="hlt">Rayleigh</span>-Taylor (RT) instability in a compressible medium was investigated both at an accelerating embedded interface and at the ablation front in a new series of experiments on Nova. The x-ray drive generated in a hohlraum ablatively accelerated a planar target consisting of a doped plastic pusher which was in some cases backed by a higher density titanium payload. Both target types were diagnosed by face-on and side-on radiography. Experiments have been done with a variety of wavelengths and initial amplitudes. In the case where the perturbed RT-unstable embedded interface is isolated from the ablation front, short wavelength perturbations are observed to grow strongly. When the perturbation is at the ablation front, the short wavelengths are observed to be severely stabilized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDD22010M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDD22010M"><span id="translatedtitle">Experiments on the rarefaction wave driven <span class="hlt">Rayleigh</span>-Taylor instability initiated with a random initial perturbation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morgan, Robert; Jacobs, Jeffrey</p> <p>2014-11-01</p> <p>Experiments are presented in which a diffuse interface between two gases is accelerated to become <span class="hlt">Rayleigh</span>-Taylor unstable. The initially flat interface is generated by the opposing flow of two test gases at matched volumetric flow rates exiting through small holes in the test section. A random, three-dimensional interface perturbation is forced using a loudspeaker. The interface is then accelerated by an expansion wave which is generated by the rupturing of a diaphragm separating the heavy gas from a vacuum tank evacuated to ~0.01 atm. The expansion wave generates a large (of order 1000 g), non-constant acceleration acting on the interface causing the <span class="hlt">Rayleigh</span>-Taylor instability to develop. Planar Mie <span class="hlt">scattering</span> is employed to visualize the flow using a planar laser sheet generated at the top of the apparatus, which illuminates smoke particles seeded in the heavy gas. The <span class="hlt">scattered</span> light is then recorded using a CMOS camera operating at 12 kHz. The mixing layer width is obtained from an ensemble of experiments and the turbulent growth parameter α is extracted and compared with previous experiments and simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820053377&hterms=Band+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DBand%2Bspectrum','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820053377&hterms=Band+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DBand%2Bspectrum"><span id="translatedtitle">Dayglow emissions of the O2 Herzberg bands and the <span class="hlt">Rayleigh</span> backscattered spectrum of the earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Frederick, J. E.; Abrams, R. B.</p> <p>1982-01-01</p> <p>It is pointed out that numerous fluorescent emissions from the Herzberg bands of molecular oxygen lie in the spectral region 242-300 nm. This coincides with the wavelength range used by orbiting spectrometers that observe the <span class="hlt">Rayleigh</span> backscattered spectrum of the earth for the purpose of monitoring the vertical distribution of stratospheric ozone. Model calculations suggest that Herzberg band emissions in the dayglow could provide significant contamination of the ozone measurements if the quenching rate of O2(A3Sigma) is sufficiently small. It is noted that this is especially true near 255 nm, where the most intense fluorescent emissions relative to the <span class="hlt">Rayleigh</span> <span class="hlt">scattered</span> signal are located and where past satellite measurements have shown a persistent excess radiance above that expected for a pure ozone absorbing and molecular <span class="hlt">scattering</span> atmosphere. Very small quenching rates, however, are adequate to reduce the dayglow emission to negligible levels. Noting that available laboratory data have not definitely established the quenching on the rate of O2(A3Sigma) as a function of vibration level, it is emphasized that such information is required before the Herzberg band contributions can be evaluated with confidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/832936','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/832936"><span id="translatedtitle">Imaging shallow objects with <span class="hlt">scattered</span> guided waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Herman, Gerard C.; Milligan, Paul A.; Huggins, Robert J.; Rector, James W.</p> <p>1999-10-01</p> <p>Current surface seismic reflection techniques based on the common-midpoint (CMP) reflection stacking method cannot be readily used to image small objects in the first few meters of a weathered layer. We discuss a seismic imaging method to detect such objects; it uses the first-arrival (guided) wave, <span class="hlt">scattered</span> by shallow heterogeneities and converted into <span class="hlt">scattered</span> <span class="hlt">Rayleigh</span> waves. These guided waves and <span class="hlt">Rayleigh</span> waves are dominant in the shallow weathered layer and therefore might be suitable for shallow object imaging. We applied this method to a field data set and found that we could certainly image meter-size objects up to about 3 m off to the side of a survey line consisting of vertical geophones. There are indications that cross-line horizontal geophone data could be used to identify shallow objects up to 10 m offline in the same region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900010097','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900010097"><span id="translatedtitle">Analytical optical <span class="hlt">scattering</span> in clouds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Phanord, Dieudonne D.</p> <p>1989-01-01</p> <p>An analytical optical model for <span class="hlt">scattering</span> of light due to lightning by clouds of different geometry is being developed. The self-consistent approach and the equivalent medium concept of Twersky was used to treat the case corresponding to outside illumination. Thus, the resulting multiple <span class="hlt">scattering</span> problem is transformed with the knowledge of the bulk parameters, into <span class="hlt">scattering</span> by a single obstacle in isolation. Based on the size parameter of a typical water droplet as compared to the incident wave length, the problem for the single <span class="hlt">scatterer</span> equivalent to the distribution of cloud particles can be solved either by Mie or <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> theory. The super computing code of Wiscombe can be used immediately to produce results that can be compared to the Monte Carlo computer simulation for outside incidence. A fairly reasonable inverse approach using the solution of the outside illumination case was proposed to model analytically the situation for point sources located inside the thick optical cloud. Its mathematical details are still being investigated. When finished, it will provide scientists an enhanced capability to study more realistic clouds. For testing purposes, the direct approach to the inside illumination of clouds by lightning is under consideration. Presently, an analytical solution for the cubic cloud will soon be obtained. For cylindrical or spherical clouds, preliminary results are needed for <span class="hlt">scattering</span> by bounded obstacles above or below a penetrable surface interface.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H13D1378G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H13D1378G"><span id="translatedtitle">Delinating Thermohaline Double-Diffusive <span class="hlt">Rayleigh</span> Regimes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graf, T.; Walther, M.; Kolditz, O.; Liedl, R.</p> <p>2013-12-01</p> <p>In natural systems, convective flow induced from density differences may occur in near-coastal aquifers, atmospheric boundary layers, oceanic streams or within the earth crust. Whether an initially stable, diffusive regime evolves into a convective (stable or chaotic) regime, or vice versa, depends on the system's framing boundary conditions. A conventional parameter to express the relation between diffusive and convective forces of such a density-driven regime is <span class="hlt">Rayleigh</span> number (Ra). While most systems are mainly dominated by only a single significant driving force (i.e. only temperature or salinity), some systems need to consider two boundary processes (e.g. deep, thus warm, haline flow in porous media). In that case, a two-dimensional, 'double-diffusive' <span class="hlt">Rayleigh</span> system can be defined. Nield (1998) postulated a boundary between diffusive and convective regime at RaT + RaC = 4pi^2 in the first quadrant (Q1), with <span class="hlt">Rayleigh</span> numbers for temperature and concentration respectively. The boundary in the forth quadrant (Q4) could not exactly be determined, yet the approximate position estimated. Simulations with HydroGeoSphere (Therrien, 2010) using a vertical, quadratic, homogeneous, isotropic setup confirmed the existence of the 4pi^2-boundary and revealed additional regimes (diffusive, single-roll, double-roll, chaotic) in Q1. Also, non-chaotic, oscillating patterns could be identified in Q4. More detailed investigations with OpenGeoSys (Kolditz, 2012) confirmed the preceding HGS results, and, using a 1:10-scaled domain (height:length), uncovered even more distinctive regimes (diffusive, minimum ten roles, supposely up to 25 roles, and chaotic?) in Q1, while again, oscillating patterns were found in the transition zone between diffusive and chaotic regimes in Q4. Output of numerical simulations from Q1 and Q4 show the mentioned regimes (diffusive, stable-convective, stable-oscillatory, chaotic) while results are displayed in context of a possible delination between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002APS..MAR.M5005V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002APS..MAR.M5005V"><span id="translatedtitle">High <span class="hlt">Rayleigh</span> number convection numerical experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verzicco, Roberto</p> <p>2002-03-01</p> <p>Numerical experiments on the flow developing in a cylindrical cell of aspect ratio Γ = 1/2 heated from below and cooled from above, are conducted for <span class="hlt">Rayleigh</span> numbers (Ra) ranging from 2 x 10^6 up to 2 x 10^11. The aim of the present study is to numerically replicate the experiments by Roche et al. (2001) and Niemela et al. (2000) performed using gaseous helium close to the critical point as working fluid (Pr = 0.7). The numerical simulation permitted us to generate a large data base which was validated by the experimental results and, on the other hand, provided physical insights which are missed by the experimental approaches usually limited to pointwise temperature and global heat exchange measurements. Attention is focussed on the presence of large-scale structures whose characterization is important owing to the introduction of constant `winds' sweeping the plates and generating viscous and thermal boundary layers. The analysis of instantaneous snapshots clearly indicates that the topology of the recirculating large scale structures is quite different with respect to what is commonly observed in Γ = 1 cells where a unique large scale recirculation structure completely fills the fluid volume (e.g. Verzicco & Camussi, 1999). It is shown that a transition occurs at about Ra = 10^9; at lower Ra the flow is characterized by the presence of two counter-rotating toroidal rings attached to the horizontal plates. At larger Ra, in contrast, the most intense structure consists of two counter-rotating rolls of unitary aspect ratio. The two types of flow, which co-exists in the range 10^9 < Ra < 10^10, determine different properties of both the thermal and the viscous boundary layers. Indeed, even if the limited range of Ra analyzed in the present simulation does not allow the presence of a transition to be clearly observed in the Nu vs Ra diagram, the proposed scenario is confirmed by the direct analysis of the boundary layer thicknesses and of the kinetic energy and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27211668','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27211668"><span id="translatedtitle">Authentication of vegetable oils by confocal X-ray <span class="hlt">scattering</span> analysis with coherent/incoherent <span class="hlt">scattered</span> X-rays.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi</p> <p>2016-11-01</p> <p>This paper presents an alternative analytical method based on the <span class="hlt">Rayleigh</span> to Compton <span class="hlt">scattering</span> intensity ratio and effective atomic number for non-destructive identification of vegetable oils using confocal energy dispersive X-ray fluorescence and <span class="hlt">scattering</span> spectrometry. A calibration curve for the <span class="hlt">Rayleigh</span> to Compton <span class="hlt">scattering</span> intensity ratio and effective atomic number was constructed on the basis of a reliable physical model for X-ray <span class="hlt">scattering</span>. The content of light elements, which are "invisible" using X-ray fluorescence, can be calculated "by difference" from the calibration curve. In this work, we demonstrated the use of this proposed approach to identify complex organic matrices in different vegetable oils with high precision and accuracy. PMID:27211668</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27211668','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27211668"><span id="translatedtitle">Authentication of vegetable oils by confocal X-ray <span class="hlt">scattering</span> analysis with coherent/incoherent <span class="hlt">scattered</span> X-rays.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi</p> <p>2016-11-01</p> <p>This paper presents an alternative analytical method based on the <span class="hlt">Rayleigh</span> to Compton <span class="hlt">scattering</span> intensity ratio and effective atomic number for non-destructive identification of vegetable oils using confocal energy dispersive X-ray fluorescence and <span class="hlt">scattering</span> spectrometry. A calibration curve for the <span class="hlt">Rayleigh</span> to Compton <span class="hlt">scattering</span> intensity ratio and effective atomic number was constructed on the basis of a reliable physical model for X-ray <span class="hlt">scattering</span>. The content of light elements, which are "invisible" using X-ray fluorescence, can be calculated "by difference" from the calibration curve. In this work, we demonstrated the use of this proposed approach to identify complex organic matrices in different vegetable oils with high precision and accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21546816','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21546816"><span id="translatedtitle">Mode competition in superradiant <span class="hlt">scattering</span> of matter waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Vogt, Thibault; Lu Bo; Liu Xinxing; Xu Xu; Zhou Xiaoji; Chen Xuzong</p> <p>2011-05-15</p> <p>Superradiant <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in a Bose gas released from an optical lattice is analyzed with incident light pumping at the Bragg angle for resonant light diffraction. We show that competition between superradiance <span class="hlt">scattering</span> into the Bragg mode and into end-fire modes clearly leads to suppression of the latter at even relatively low lattice depths. A quantum light-matter interaction model is proposed for qualitatively explaining this result.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304238','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304238"><span id="translatedtitle">Suppression of <span class="hlt">Rayleigh</span> Taylor instability in strongly coupled plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Das, Amita; Kaw, Predhiman</p> <p>2014-06-15</p> <p>The <span class="hlt">Rayleigh</span> Taylor instability in a strongly coupled plasma medium has been investigated using the equations of generalized hydrodynamics. It is demonstrated that the visco-elasticity of the strongly coupled medium due to strong inter particle correlations leads to a suppression of the <span class="hlt">Rayleigh</span> Taylor instability unless certain threshold conditions are met. The relevance of these results to experiments on laser compression of matter to high densities including those related to inertial confinement fusion using lasers has also been shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JPCM...22D4019T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JPCM...22D4019T"><span id="translatedtitle">Elastic and inelastic <span class="hlt">scattering</span> of He atoms from Bi(111)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tamtögl, A.; Mayrhofer-Reinhartshuber, M.; Balak, N.; Ernst, W. E.; Rieder, K. H.</p> <p>2010-08-01</p> <p>Elastic and inelastic <span class="hlt">scattering</span> of helium atoms has been used to study the Bi(111) surface. Sharp diffraction peaks are found with results in excellent agreement with previous structure determinations of the Bi(111) surface. The rather large first order peaks with respect to the zero order peak indicate a stronger surface corrugation than observed in helium <span class="hlt">scattering</span> from other metallic surfaces. Time-of-flight spectra of <span class="hlt">scattered</span> He atoms clearly reveal two inelastic <span class="hlt">scattering</span> maxima, which allow a first report on phonon creation and annihilation events on the Bi(111) surface. An estimate of the group velocity shows that the phonon creation peak is likely to correspond to a <span class="hlt">Rayleigh</span> mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012HEDP....8...71C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012HEDP....8...71C"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability simulations with CRASH</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chou, C.-C.; Fryxell, B.; Drake, R. P.</p> <p>2012-03-01</p> <p>CRASH is a code package developed for the predictive study of radiative shocks. It is based on the BATSRUS MHD code used extensively for space-weather research. We desire to extend the applications of this code to the study of hydrodynamically unstable systems. We report here the results of <span class="hlt">Rayleigh</span>-Taylor instability (RTI) simulations with CRASH, as a necessary step toward the study of such systems. Our goal, motivated by the previous comparison of simulations and experiment, is to be able to simulate the magnetic RTI with self-generated magnetic fields produced by the Biermann Battery effect. Here we show results for hydrodynamic RTI, comparing the effects of different solvers and numerical parameters. We find that the early-time behavior converges to the analytical result of the linear theory. We observe that the late-time morphology is sensitive to the numerical scheme and limiter beta. At low-resolution limit, the growth of RTI is highly dependent on the setup and resolution, which we attribute to the large numerical viscosity at low resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/57374','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/57374"><span id="translatedtitle"><span class="hlt">Rayleigh</span> lidar observations of mesosphere temperature structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meriwether, J.W.; Dao, P.D.; Mcnutt, R.T.; Klemetti, W.; Moskowitz, W.; Davidson, G. |</p> <p>1994-08-01</p> <p>Ground-based observations of atmospheric density profiles to 92 km were obtained for four successive seasons between summer 1989 and spring 1990. These results were obtained with a powerful <span class="hlt">Rayleigh</span> lidar facility located at Wright Patterson Air Force Base (Dayton, Ohio). This instrument combined a 14-W XeF laser transmitter with a 2.54-m receiver mirror to observe returns from altitudes between 40 and 95 km. Analysis of the scale height dependence of the density profiles produced temperatures with a measurement error of about 5 K (approximately 2.5%) at 90 km when the lidar data was averaged for 20 min. and smoothed in height over 2.7 km. Examination of these profiles for the total of 18 nights showed that there often existed in the mesophere a layer of enhanced temperatures when compared with the U.S. standard profile. The layer centroid height was about 85 km for summer and 70 to 75 km for winter. Data obtained for the equinoctial periods showed the amplitude of these layers to be weak. The winter temperature profiles showed evidence for long-period waves passing through the region of the thermal anomaly while the equinox profiles revealed more sporadic wave activity with shorter vertical wavelengths. Both the winter and summer temperature data displayed regions where the observed lapse rate approached the adiabatic lapse rate. In the summer the wave activity near the iversion layer was weak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814411D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814411D"><span id="translatedtitle">Deuterium excess in the <span class="hlt">Rayleigh</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dütsch, Marina; Pfahl, Stephan; Sodemann, Harald</p> <p>2016-04-01</p> <p>The deuterium excess is a useful quantity for measuring nonequilibrium effects of isotopic fractionation, and can therefore provide information about the meteorological conditions in evaporation regions (e.g., relative humidity over the ocean or the fraction of plant transpiration over land). In addition to nonequilibrium fractionation, there are two other effects that can change the deuterium excess during phase transitions. The first is the dependence of the equilibrium fractionation factors on temperature, the second is the nonlinearity of the delta scale, on which the deuterium excess is defined. We tested the impact of these three effects (nonequilibrium, temperature and delta scale) in a simple <span class="hlt">Rayleigh</span> condensation model simulating the isotopic composition of an air parcel during a moist adiabatic ascent. The delta scale effect is important especially for depleted air parcels where it can change the sign of the deuterium excess in the remaining vapour from negative to positive. In this case the deuterium excess to a large extent reflects an artefact of its own definition, which overwrites both the nonequilibrium and the temperature effect. This problem can be solved by an alternative definition for the deuterium excess that is not based on the delta scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDKP1092S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDKP1092S"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor mixing in supernova experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swisher, Nora; Kuranz, Carolyn; Arnett, David; Hurricane, Omar; Remington, Bruce; Robey, Harry; Abarzhi, Snezhana</p> <p>2015-11-01</p> <p>We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced <span class="hlt">Rayleigh</span>-Taylor (RT) mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of RT flow in supernova experiments, and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By proper accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are identified to describe asymptotic dynamics of RT flow with time-dependent acceleration by applying theoretical analysis. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments, the RT flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; the mixing flow may keep order. Support of the National Science Foundation is warmly appreciated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/955656','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/955656"><span id="translatedtitle">A Comparison of Short <span class="hlt">Rayleigh</span> Range FEL Performance with Simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Benson, Stephen; Evtushenko, Pavel; Michelle D. Shinn; Neil, George; Blau, Joe; Burggraff, D.; Colson, William; Crooker, P.P.; Sans Aguilar, J.</p> <p>2007-08-01</p> <p>One approach to attaining very high power in a free-electron laser (FEL) is to operate with a <span class="hlt">Rayleigh</span> range much smaller than the wiggler length. Previously, 3D simulations of Free-electron laser (FEL) oscillators showed that FEL gain doesn't fall off with <span class="hlt">Rayleigh</span> range as predicted by one-dimensional simulations*. They also predict that the angular tolerance for the mirrors is much large than simplistic theory predicts. Using the IR Upgrade laser at Jefferson Lab lasing at 935 nm we have studied the performance of an FEL with very short <span class="hlt">Rayleigh</span> range. We also looked at the angular sensitivity for several different <span class="hlt">Rayleigh</span> ranges. We find very good agreement between simulations and measured gain and angular sensitivities. Surprisingly the gain continues to rise as the <span class="hlt">Rayleigh</span> range is shortened and continues to grow even when the resonator becomes geometrically unstable. The same behavior is seen in both the experiment and simulations. We also find that, even for large <span class="hlt">Rayleigh</span> r</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..GECGT1073S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..GECGT1073S"><span id="translatedtitle">Laser Thomson <span class="hlt">scattering</span> in a pulsed atmospheric arc discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sommers, Bradley; Adams, Steven</p> <p>2015-09-01</p> <p>Laser <span class="hlt">scattering</span> measurements, including <span class="hlt">Rayleigh</span>, Raman, and Thomson <span class="hlt">scattering</span> have been performed on an atmospheric pulsed arc discharge. Such laser <span class="hlt">scattering</span> techniques offer a non-invasive diagnostic to measure gas temperature, electron temperature, and electron density in atmospheric plasma sources, particularly those with feature sizes approaching 1 mm. The pulsed discharge is ignited in a pin to pin electrode geometry using a 6 kV pulse with 10 ns duration. The electrodes are housed in a glass vacuum chamber filled with argon gas. The laser signal is produced by a Nd:Yag laser supply, repetitively pulsed at 10 Hz and frequency quadrupled to operate at 266 nm. The <span class="hlt">scattered</span> laser signal is imaged onto a triple grating spectrometer, which is used to suppress the <span class="hlt">Rayleigh</span> <span class="hlt">scatter</span> signal in order to measure the low amplitude Thomson and Raman signals. Preliminary results include measurements of electron temperature and electron density in the plasma column taken during the evolution of the discharge. The laser system is also used to measure the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> signal, which provides space and time resolved measurements of gas temperature in the arc discharge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27283092','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27283092"><span id="translatedtitle">Brillouin <span class="hlt">scattering</span> self-cancellation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Florez, O; Jarschel, P F; Espinel, Y A V; Cordeiro, C M B; Mayer Alegre, T P; Wiederhecker, G S; Dainese, P</p> <p>2016-01-01</p> <p>The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin <span class="hlt">scattering</span> in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin <span class="hlt">scattering</span> arising from <span class="hlt">Rayleigh</span> acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it. PMID:27283092</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCo...711759F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCo...711759F"><span id="translatedtitle">Brillouin <span class="hlt">scattering</span> self-cancellation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.</p> <p>2016-06-01</p> <p>The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin <span class="hlt">scattering</span> in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin <span class="hlt">scattering</span> arising from <span class="hlt">Rayleigh</span> acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4906398','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4906398"><span id="translatedtitle">Brillouin <span class="hlt">scattering</span> self-cancellation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.</p> <p>2016-01-01</p> <p>The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin <span class="hlt">scattering</span> in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin <span class="hlt">scattering</span> arising from <span class="hlt">Rayleigh</span> acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon–phonon interaction, enhancing or suppressing it. PMID:27283092</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.207.1062B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.207.1062B"><span id="translatedtitle">Effects of elastic focusing on global models of <span class="hlt">Rayleigh</span> wave attenuation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bao, Xueyang; Dalton, Colleen A.; Ritsema, Jeroen</p> <p>2016-11-01</p> <p><span class="hlt">Rayleigh</span> wave amplitudes are the primary data set used for imaging shear attenuation in the upper mantle on a global scale. In addition to attenuation, surface-wave amplitudes are influenced by excitation at the earthquake source, focusing and <span class="hlt">scattering</span> by elastic heterogeneity, and local structure at the receiver and the instrument response. The challenge of isolating the signal of attenuation from these other effects limits both the resolution of global attenuation models and the level of consistency between different global attenuation studies. While the source and receiver terms can be estimated using relatively simple approaches, focusing effects on amplitude are a large component of the amplitude signal and are sensitive to multiscale velocity anomalies. In this study we investigate how different theoretical treatments for focusing effects on <span class="hlt">Rayleigh</span> wave amplitude influence the retrieved attenuation models. A new data set of fundamental-mode <span class="hlt">Rayleigh</span> wave phase and amplitude at periods of 50 and 100 sis analysed. The amplitudes due to focusing effects are predicted using the great-circle ray approximation (GCRA), exact ray theory (ERT), and finite-frequency theory (FFT). Phase-velocity maps expanded to spherical-harmonic degree 20 and degree 40 are used for the predictions. After correction for focusing effects, the amplitude data are inverted for global attenuation maps and frequency-dependent source and receiver correction factors. The degree-12 attenuation maps, based on different corrections for focusing effects, all contain the same large-scale features, though the magnitude of the attenuation variations depends on the focusing correction. The variance reduction of the amplitudes strongly depends on the predicted focusing amplitudes, with the highest variance reduction for the ray-based approaches at 50 s and for FFT at 100 s. Although failure to account for focusing effects introduces artefacts into the attenuation models at higher spherical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/902231','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/902231"><span id="translatedtitle">Aluminum <span class="hlt">Rayleigh</span> Taylor Strength Measurements and Calculations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lindquist, M J; Cavallo, R M; Lorenz, K T; Pollaine, S M; Remington, B A; Raevsky, V A</p> <p>2007-01-10</p> <p>A traditional approach to the study of material strength has been revitalized at the Russian Federal Nuclear Center (VNIIEF). <span class="hlt">Rayleigh</span> Taylor strength experiments have long been utilized to measure the material response of metals at high pressure and strain rates. A modulated (sinusoidal or sawtooth perturbation) surface is shocklessly (quasi-isentropically) accelerated by a high explosive (HE) driver, and radiography is used to measure the perturbation amplitude as a function of time. The Aluminum T-6061 targets are designed with several sets of two-dimensional sawtooth perturbations machined on the loading surface. The HE driver was designed to reach peak pressures in the range of 200 to 300 kbar and strain rates in the range of 10{sup 4} - 10{sup 6} s{sup -1}. The standard constitutive strength models, Steinberg-Guinan (SG) [1], Steinberg-Lund (SL) [2], Preston-Tonks-Wallace (PTW) [3], Johnson-Cooke (JC) [4], and Mechanical Threshold Stress (MTS) [5], have been calibrated by traditional techniques: (Hopkinson-Bar, Taylor impact, flyer plate/shock-driven experiments). The VNIIEF experimental series accesses a strain rate regime not attainable using traditional methods. We have performed a detailed numerical study with a two-dimensional Arbitrary Lagrangian Eulerian hydrodynamics computer code containing several constitutive strength models to predict the perturbation growth. Results show that the capabilities of the computational methodology predict the amplitude growth to within 5 percent of the measured data, thus validating both the code and the strength models under the given conditions and setting the stage for credible future design work using different materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810043455&hterms=fraunhofer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dfraunhofer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810043455&hterms=fraunhofer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dfraunhofer"><span id="translatedtitle">Inelastic <span class="hlt">scattering</span> in planetary atmospheres. I - The Ring effect, without aerosols</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kattawar, G. W.; Young, A. T.; Humphreys, T. J.</p> <p>1981-01-01</p> <p>The contribution of inelastic molecular <span class="hlt">scattering</span> (<span class="hlt">Rayleigh</span>-Brillouin and rotational Raman <span class="hlt">scattering</span>) to the filling-in of Fraunhofer lines in the light of the blue sky is studied. Aerosol fluorescence is shown to be negligible, and aerosol <span class="hlt">scattering</span> is ignored. The angular and polarization dependences of the filling-in detail for single <span class="hlt">scattering</span> are discussed. An approximate treatment of multiple <span class="hlt">scattering</span>, using a backward Monte Carlo technique, makes it possible to investigate the effects of the ground albedo. As the molecular <span class="hlt">scatterings</span> alone produce more line-filling than is observed, it seems likely that aerosols dilute the effect by contributing unaltered sunlight to the observed spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DPPTP9075P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DPPTP9075P"><span id="translatedtitle">Observation of the <span class="hlt">Rayleigh</span>-Taylor instability in a dusty plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pacha, K. A.; Merlino, R. L.; Heinrich, J. R.; Kim, S. H.</p> <p>2011-10-01</p> <p>Lord <span class="hlt">Rayleigh</span> showed that the interface between two fluids of different densities, with the dense fluid above a fluid of lesser density, is unstable to the growth of downward moving irregularities which develop into finger-like structures. Taylor showed that this situation is equivalent to one in which a lighter fluid is accelerated into a heavier fluid. We have observed a Taylor-type instability in a dusty plasma formed in a dc-glow discharge in argon at P = 13 Pa. The glow discharge is formed using a 4 cm diameter anode disk biased at 300 V with respect to the walls of a vacuum chamber. An axial magnetic field ~30 mT confines the glow to a cylindrical region protruding outward from the anode. Micron size spherical iron particles are incorporated into the discharge from a floating tray located below the anode. The conical dust suspension is separated into a region of high dust density near the anode and a low density region farther from the anode. Periodically, the boundary of the high density region is locally perturbed by a pressure disturbance from the low density region. The surface irregularity grows rapidly, forming a bubble and spike, classic signatures of the <span class="hlt">Rayleigh</span>-Taylor instability. The instability is studied with laser light <span class="hlt">scattering</span> and video imaging. This work was supported by DOE Grant No. DE-FG01-04ER54795.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19381184','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19381184"><span id="translatedtitle">Performance evaluation of a dual fringe-imaging Michelson interferometer for air parameter measurements with a 355 nm <span class="hlt">Rayleigh</span>-Mie lidar.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cézard, Nicolas; Dolfi-Bouteyre, Agnès; Huignard, Jean-Pierre; Flamant, Pierre H</p> <p>2009-04-20</p> <p>A new concept of spectrum analyzer is proposed for short-range lidar measurements in airborne applications. It implements a combination of two fringe-imaging Michelson interferometers to analyze the <span class="hlt">Rayleigh</span>-Mie spectrum backscattered by molecules and particles at 355 nm. The objective is to perform simultaneous measurements of four variables: the air speed, the air temperature and density, and the particle <span class="hlt">scattering</span> ratio. The Cramer-Rao bounds are calculated to evaluate the best expectable measurement accuracies. The performance optimization shows that a Michelson interferometer with a path difference of 3 cm is optimal for air speed measurements in clear air. To optimize density, temperature, and <span class="hlt">scattering</span> ratio measurements, the second interferometer should be set to a path difference of 10 cm at least; 20 cm would be better to be less sensitive to the actual <span class="hlt">Rayleigh</span>-Brillouin line shape. PMID:19381184</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22351487','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22351487"><span id="translatedtitle">Non-coherent continuum <span class="hlt">scattering</span> as a line polarization mechanism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Del Pino Alemán, T.; Manso Sainz, R.; Trujillo Bueno, J. E-mail: rsainz@iac.es</p> <p>2014-03-20</p> <p>Line <span class="hlt">scattering</span> polarization can be strongly affected by <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> at neutral hydrogen and Thomson <span class="hlt">scattering</span> at free electrons. Often a depolarization of the continuum results, but the Doppler redistribution produced by the continuum <span class="hlt">scatterers</span>, which are light (hence, fast), induces more complex interactions between the polarization in spectral lines and in the continuum. Here we formulate and solve the radiative transfer problem of <span class="hlt">scattering</span> line polarization with non-coherent continuum <span class="hlt">scattering</span> consistently. The problem is formulated within the spherical tensor representation of atomic and light polarization. The numerical method of solution is a generalization of the Accelerated Lambda Iteration that is applied to both the atomic system and the radiation field. We show that the redistribution of the spectral line radiation due to the non-coherence of the continuum <span class="hlt">scattering</span> may modify the shape of the emergent fractional linear polarization patterns significantly, even yielding polarization signals above the continuum level in intrinsically unpolarizable lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730045361&hterms=1084&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231084','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730045361&hterms=1084&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231084"><span id="translatedtitle">Matrix operator theory of radiative transfer. II - <span class="hlt">Scattering</span> from maritime haze.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kattawar, G. W.; Plass, G. N.; Catchings, F. E.</p> <p>1973-01-01</p> <p>Matrix operator theory is used to calculate the reflected and transmitted radiance of photons that have interacted with plane-parallel maritime haze layers. The results are presented for three solar zenith angles, three values of the surface albedo, and a range of optical thicknesses from very thin to very thick. The diffuse flux at the lower boundary and the cloud albedo are tabulated. The forward peak and other features in the single-<span class="hlt">scattered</span> phase function cause the radiance in many cases to be very different from that for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. In particular, the variation of the radiance with both the zenith or nadir angle and the azimuthal angle is more marked and the relative limb darkening under very thick layers is greater for haze M than for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. The downward diffuse flux at the lower boundary for A = 0 is always greater and the cloud albedo is always less for haze M than for <span class="hlt">Rayleigh</span> layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720012688','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720012688"><span id="translatedtitle">Discrete ordinate theory of radiative transfer. 2: <span class="hlt">Scattering</span> from maritime haze</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kattawar, G. W.; Plass, G. N.; Catchings, F. E.</p> <p>1971-01-01</p> <p>Discrete ordinate theory was used to calculate the reflected and transmitted radiance of photons which have interacted with plane parallel maritime haze layers. The results are presented for three solar zenith angles, three values of the surface albedo, and a range of optical thicknesses from very thin to very thick. The diffuse flux at the lower boundary and the cloud albedo were tabulated. The forward peak and other features in the single <span class="hlt">scattered</span> phase function caused the radiance in many cases to be very different from that for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. The variation of the radiance with both the zenith or nadir angle and the azimuthal angle is more marked, and the relative limb darkening under very thick layers is greater, for haze than for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. The downward diffuse flux at the lower boundary for A = O is always greater and the cloud albedo is always less for haze than for <span class="hlt">Rayleigh</span> layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5086887','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5086887"><span id="translatedtitle">Calibration of the ORNL two-dimensional Thomson <span class="hlt">scattering</span> system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thomas, C.E. Jr.; Lazarus, E.A.; Kindsfather, R.R.; Murakami, M.; Stewart, K.A.</p> <p>1985-10-01</p> <p>A unified presentation of the calibrations needed for accurate calculation of electron temperature and density from Thomson <span class="hlt">scattering</span> data for the Oak Ridge National Laboratory two-dimensional Thomson <span class="hlt">scattering</span> system (SCATPAK II) is made. Techniques are described for measuring the range of wavelengths to which each channel is responsive. A statistical method for calibrating the gain of each channel in the system is given, and methods of checking for internal consistency and accuracy are presented. The relationship between the constants describing the relative light collection efficiency of each channel and plasma light-<span class="hlt">scattering</span> theory is developed, methods for measuring the channel efficiencies and evaluating their accuracy are described, and the effect on these constants of bending fiber optics is discussed. The use of <span class="hlt">Rayleigh</span> or Raman <span class="hlt">scattering</span> for absolute efficiency (density) calibration, stray light measurement, and system efficiency evaluation is discussed; the relative merits of <span class="hlt">Rayleigh</span> vs Raman <span class="hlt">scattering</span> are presented; and the relationship among the <span class="hlt">Rayleigh</span>/Raman calibrations, relative channel efficiency constants, and absolute efficiencies is developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930046612&hterms=zones+ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dzones%2Bocean','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930046612&hterms=zones+ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dzones%2Bocean"><span id="translatedtitle">Comment on 'Aerosol and <span class="hlt">Rayleigh</span> radiance contributions to Coastal Zone Colour Scanner images' by Eckstein and Simpson</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gordon, H. R.; Evans, R. H.</p> <p>1993-01-01</p> <p>In a recent paper Eckstein and Simpson describe what they believe to be serious difficulties and/or errors with the CZCS (Coastal Zone Color Scanner) processing algorithms based on their analysis of seven images. Here we point out that portions of their analysis, particularly those dealing with multiple <span class="hlt">scattered</span> <span class="hlt">Rayleigh</span> radiance, are incorrect. We also argue that other problems they discuss have already been addressed in the literature. Finally, we suggest that many apparent artifacts in CZCS-derived pigment fields are likely to be due to inadequacies in the sensor band set or to poor radiometric stability, both of which will be remedied with the next generation of ocean color sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDA22005M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDA22005M"><span id="translatedtitle">Dynamics of <span class="hlt">Rayleigh</span>-Taylor driven flows at high Atwood numbers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mikhaeil, Mark; Akula, Bhanesh; Finn, Thomas; Ranjan, Devesh</p> <p>2014-11-01</p> <p>For the first time, detailed simultaneous density and velocity turbulent statistics for <span class="hlt">Rayleigh</span>-Taylor instabilities at Atwood number of 0.75 are measured. A new density probe capable of measuring gas volumetric concentration directly is used in parallel to a three-wire probe to obtain instantaneous density and velocity components simultaneously. Particle Image Velocimetry (PIV) is also implemented to obtain field-wise measurements. The self-similarity behavior of the velocity statistics, corresponding probability density function (PDF) and spectra are presented. Mie-<span class="hlt">scattering</span> images taken in both stream-wise and span-wise direction at different instability times have illustrated the turbulent structures visible in the instability. This work is graciously supported by DOE-National Nuclear Security Administration Grant Number DE-NA0001786.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11913007W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11913007W"><span id="translatedtitle">Early Temperatures Observed with the Extremely Sensitive <span class="hlt">Rayleigh</span> Lidar at Utah State University</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wickwar, Vincent B.; Sox, Leda; Emerick, Matthew T.; Herron, Joshua P.; Barton, David L.</p> <p>2016-06-01</p> <p><span class="hlt">Rayleigh-scatter</span> lidar observations were made at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU) from 1993-2004 from 45-90 km. The lidar operated at 532 nm with a power-aperture-product (PAP) of ~3.1 Wm2. The sensitivity of the lidar has since been increased by a factor of 66 to 205 Wm2, extending the maximum altitude into new territory, the lower thermosphere. Observations have been extended up to 115 km, almost to the 120 km goal. Early temperatures from four ~4-week periods starting in June 2014 are presented and discussed. They are compared to each other, to the ALO climatology from the original lidar [1], and to temperatures from the NRLMSISe00 empirical model [2].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMOp...61..954S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMOp...61..954S"><span id="translatedtitle">Radiation forces on a <span class="hlt">Rayleigh</span> particle by a highly focused elliptically polarized beam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shu, Jianhua; Liu, Yongxin; Chen, Ziyang; Pu, Jixiong</p> <p>2014-06-01</p> <p>The radiation force of highly focused elliptically polarized beams on a <span class="hlt">Rayleigh</span> particle is theoretically studied. The numerical results show that elliptically polarized beams can be used to trap particles. The influence of the beam widths, phase retardations of the incident beam, and numerical apertures of an objective lens on the radiation force distribution has been studied. Studies in transverse <span class="hlt">scattering</span> forces reveal that torques can be produced by elliptically polarized beams carrying spin angular momentum, and that the torque, in the focal plane, produced by elliptically polarized beams can be regarded as the superposition of those by right-hand circularly and left-hand circularly polarized beams with different ratios between them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......238C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......238C"><span id="translatedtitle">Crash simulation of <span class="hlt">rayleigh</span>-taylor, richtmyer-meshkov, and magnetic <span class="hlt">rayleigh</span>-taylor instability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chou, Jason Chuan-Chih</p> <p></p> <p>The research discussed in this thesis was motivated by the supernova <span class="hlt">Rayleigh</span>-Taylor (SNRT) experiments conducted in 2009. Originally designed as laboratory astrophysics experiments relevant to the <span class="hlt">Rayleigh</span>-Taylor Instability (RTI) at the He-H interface during supernova explosion, these experiments exhibited unusual late-time morphology development, characterized by the lack of mushroom caps and uniform width of the spikes. In response, a "Magnetic Straitjacket" hypothesis was proposed to explain the discrepancy, based on the Biermann Battery mechanism. In order to test this hypothesis, we used the Center for Radiative Shock Hydrodynamics (CRASH) code developed for a sufficiently similar problem and with the necessary capabilities. We validated this alternative usage of the CRASH code with simulations of pure hydrodynamic RTI and Richtmyer-Meshkov Instability (RMI) and identified the suitable combinations of numerical schemes and parameters. For the RTI, we compared the results of simulations to the analytical solution for the early time behavior, examined the late-time morphology, and tested the low-resolution limit for the RTI simulations using CRASH. For the RMI, we modeled Collins and Jacobs' experiment and compared the results of CRASH simulations to the experimental observations as well as to the simulation results of several other code packages. Finally, we modeled the original SNRT experiments with magnetohydrodynamics (MHD) and Biermann battery effect. Unfortunately, the results were inconclusive due to insufficiently resolved simulations, limited by the explicit time integration of the magnetic diffusion. Furthermore, pilot runs with higher resolution indicated that simulations that fully resolve the gradients necessary to calculate the Biermann battery effect may be susceptible to the development of extraneous small-wavelength instabilities. Developments of implicit time integration of the magnetic diffusion and possibly new numerical schemes are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920020045&hterms=remote+Raman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dremote%2BRaman','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920020045&hterms=remote+Raman&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dremote%2BRaman"><span id="translatedtitle">Efficiencies of Rotational Raman, and <span class="hlt">Rayleigh</span> Techniques for Laser Remote Sensing of the Atmospheric Temperature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ivanova, I. D.; Gurdev, L. L.; Mitev, V. M.</p> <p>1992-01-01</p> <p>Various lidar methods have been developed for measuring the atmospheric temperature, making use of the temperature dependant characteristics of rotational Raman <span class="hlt">scattering</span> (RRS) from nitrogen and oxygen, and <span class="hlt">Rayleigh</span> or <span class="hlt">Rayleigh</span>-Brillowin <span class="hlt">scattering</span> (RS or RBS). These methods have various advantages and disadvantages as compared to each other but their potential accuracies are principal characteristics of their efficiency. No systematic attempt has been undertaken so far to compare the efficiences, in the above meaning, of different temperature lidar methods. Two RRS techniques have been compared. Here, we do such a comparison using two methods based on the detection and analysis of RS (RBS) spectra. Four methods are considered here for measuring the atmospheric temperature. One of them (Schwiesow and Lading, 1981) is based on an analysis of the RS linewidth with two Michelson interferometers (MI) in parallel. The second method (Shimisu et al., 1986) employs a high-resolution analysis of the RBS line shape. The third method (Cooney, 1972) employs the temperature dependance of the RRS spectrum envelope. The fourth method (Armstrong, 1974) makes use of a scanning Fabry-Perot interferometer (FPI) as a comb filter for processing the periodic RRS spectrum of the nitrogen. Let us denote the corresponding errors in measuring the temperature by sigma(sub MI), sigma(sub HR), sigma(sub ENV), and sigma(sub FPI). Let us also define the ratios chi(sub 1) = sigma(sub MI)/sigma(sub ENV), chi(sub 2) = sigma(sub HR)/sigma(sub ENV), and chi(sub 3) = sigma(sub FPI)/sigma(sub ENV) interpreted as relative errors with respect to sigma(sub ENV).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApGeo..11..167Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApGeo..11..167Z"><span id="translatedtitle"><span class="hlt">Rayleigh</span> wave nonlinear inversion based on the Firefly algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Teng-Fei; Peng, Geng-Xin; Hu, Tian-Yue; Duan, Wen-Sheng; Yao, Feng-Chang; Liu, Yi-Mou</p> <p>2014-06-01</p> <p><span class="hlt">Rayleigh</span> waves have high amplitude, low frequency, and low velocity, which are treated as strong noise to be attenuated in reflected seismic surveys. This study addresses how to identify useful shear wave velocity profile and stratigraphic information from <span class="hlt">Rayleigh</span> waves. We choose the Firefly algorithm for inversion of surface waves. The Firefly algorithm, a new type of particle swarm optimization, has the advantages of being robust, highly effective, and allows global searching. This algorithm is feasible and has advantages for use in <span class="hlt">Rayleigh</span> wave inversion with both synthetic models and field data. The results show that the Firefly algorithm, which is a robust and practical method, can achieve nonlinear inversion of surface waves with high resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhRvE..69b6302B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhRvE..69b6302B"><span id="translatedtitle">Effect of inertia in <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Breuer, M.; Wessling, S.; Schmalzl, J.; Hansen, U.</p> <p>2004-02-01</p> <p>We have investigated the influence of the Prandtl number on the dynamics of high <span class="hlt">Rayleigh</span> number thermal convection. A numerical parameter study in a three-dimensional <span class="hlt">Rayleigh</span>-Bénard configuration was carried out, where we varied the Prandtl number between 10-3⩽Pr⩽102. The <span class="hlt">Rayleigh</span> number was fixed at a value of Ra=106. Our main focus lay on the question how the value of the Prandtl number affects the spatial structure of the flow. We investigated the functional dependence of the Nusselt number and the Reynolds number and compared our results with a recent theoretical approach of Grossmann and Lohse [J. Fluid Mech. 407, 27 (2000); Phys. Rev. Lett. 86, 3316 (2001)].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6566049','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6566049"><span id="translatedtitle">Thomson <span class="hlt">scattering</span> as a method for laser plasma diagnostics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Alayi, Y.</p> <p>1983-12-01</p> <p>The Thomson <span class="hlt">scattering</span> has been used to determine the density and temperature of an inhomogeneous nonstationary plasma. A common method to calibrate the Thomson <span class="hlt">scattering</span> device consists in replacing the plasma by a gas and measuring the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> cross section. The angular distribution of the <span class="hlt">scattered</span> light in Argon is measured, the incident light is a ruby laser with ..delta..t = 30ns and lambda = 6943nm and vertically polarized. We have found that angular distribution is strongly favored in the forward direction (30/sup 0/, 45/sup 0/, 60/sup 0/) and defavored for backward direction (90/sup 0/, 120/sup 0/, 135/sup 0/, 150/sup 0/) in agreement with the results of George, et al, but in disagreement with the <span class="hlt">Rayleigh</span> theory which assumes a uniform distribution. Our results may be related to the form of the <span class="hlt">scattered</span> light spectrum which undergoes a dramatic change through the kinetic-hydrodynamic transition. The general form of the spectrum is determined by the parameter y = 1/Kl (where K = 4..pi.. sin (theta/2)/lambda, theta is the <span class="hlt">scattering</span> angle and l is the free path path), which increases in the direction of the hydrodynamic regime (small angles). By analogy, the Thomson <span class="hlt">scattering</span> presents the same aspects with ..cap alpha.. = 1/Klambda /SUB D/ (where lambda /SUB D/ is the Debye length). The deviation from the uniform distribution provides the possibility to determine the plasma turbulence spectrum from the <span class="hlt">scattered</span> light.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70027334','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70027334"><span id="translatedtitle">Study on evaluation methods for <span class="hlt">Rayleigh</span> wave dispersion characteristic</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shi, L.; Tao, X.; Kayen, R.; Shi, H.; Yan, S.</p> <p>2005-01-01</p> <p>The evaluation of <span class="hlt">Rayleigh</span> wave dispersion characteristic is the key step for detecting S-wave velocity structure. By comparing the dispersion curves directly with the spectra analysis of surface waves (SASW) method, rather than comparing the S-wave velocity structure, the validity and precision of microtremor-array method (MAM) can be evaluated more objectively. The results from the China - US joint surface wave investigation in 26 sites in Tangshan, China, show that the MAM has the same precision with SASW method in 83% of the 26 sites. The MAM is valid for <span class="hlt">Rayleigh</span> wave dispersion characteristic testing and has great application potentiality for site S-wave velocity structure detection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GeoJI.159..978F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GeoJI.159..978F"><span id="translatedtitle">Lithospheric imaging via teleseismic <span class="hlt">scattering</span> tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frederiksen, A. W.; Revenaugh, J.</p> <p>2004-12-01</p> <p>The coda of the teleseismic P phase consists largely of energy <span class="hlt">scattered</span> by small inhomogeneities in the receiver-side lithosphere. Given large collections of teleseismic data from dense permanent networks, previous workers have successfully back-propagated coda energy back to <span class="hlt">scattering</span> source points using various kinematic migration schemes, as well as by inverting using an inverse <span class="hlt">scattering</span>/radon transform approach. Under the Born approximation, seismic <span class="hlt">scattering</span> is a linear process; therefore it is possible to approach coda <span class="hlt">scattering</span> as a linear waveform inversion problem, mathematically similar to transmission-based tomography. Assuming ray-theoretical propagation and <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, we pose the inverse <span class="hlt">scattering</span> problem in tomographic form, and recover perturbations in density and P and S velocities from Pp and Ps <span class="hlt">scattered</span> data. The method is applied to data from the Southern California Seismic Network (SCSN) covering the San Jacinto-Anza region. The results show a considerable correlation between seismicity and velocity perturbation structure, particularly in the region between the Mission Creek and Banning fault branches. Features connecting the Coyote Creek and Elsinore faults at right angles are correlated with seismicity lineations and may represent conjugate faulting with no surface expression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20853265','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20853265"><span id="translatedtitle">Light <span class="hlt">scattering</span> by a thin wire with a surface-plasmon resonance: Bifurcations of the Poynting vector field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Luk'yanchuk, B. S.; Ternovsky, V.</p> <p>2006-06-15</p> <p>We analyze the energy flow during the <span class="hlt">scattering</span> of a plane wave by a small homogeneous cylinder in the vicinity of surface-plasmon resonance, where {epsilon}{sup '}=Re {epsilon}=-1 ({epsilon} stands for permittivity). For the case of small dissipation, {epsilon}{sup ''}=Im {epsilon}<<1, this <span class="hlt">scattering</span> can strongly deviate from the classical dipole approximation (<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>). In certain specified cases, the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> is replaced with an anomalous light <span class="hlt">scattering</span> regardless the wire smallness. The phenomenon is based on interplay of the usual dissipative and radiative damping, where the latter is related to inverse transformation of localized resonant plasmons into <span class="hlt">scattered</span> light. The anomalous light <span class="hlt">scattering</span> possesses a variety of unusual features, such as an inverse hierarchy of optical resonances and a complicated near-field structure, which may include optical vortexes, optical whirlpools, and other peculiarities in nanoscale area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056915&hterms=microwave+soil&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmicrowave%2Bsoil','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056915&hterms=microwave+soil&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmicrowave%2Bsoil"><span id="translatedtitle">Modelling of microwave emission and <span class="hlt">scattering</span> from snow and soil</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fung, Adrian K.; Chen, M. F.</p> <p>1989-01-01</p> <p>In the past a snow layer has been modeled as a homogeneous layer embedded with sparsely populated <span class="hlt">Rayleigh</span> <span class="hlt">scatterers</span> above an irregular ground surface. The effect of the ground surface can be ignored if the layer is sufficiently lossy due to wetness in the snow. The top surface of the snow layer may be treated as plane or irregular depending upon its actual shape and its wetness condition. For a dry snow condition where the electromagnetic wave can penetrate easily one can ignore the air-snow interface. As a result a variety of emission and <span class="hlt">scattering</span> models exist. An improvement to the existing <span class="hlt">scattering</span> or emission model would consist of an irregular layer with densely populated correlated <span class="hlt">scatterers</span>. The development of this model and its application to <span class="hlt">scattering</span> and emission from a snow layer are discussed. Also disucssed is a surface <span class="hlt">scattering</span> model for a soil surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24323100','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24323100"><span id="translatedtitle">Coherent effects in the <span class="hlt">scattering</span> of light from two-dimensional rough metal surfaces.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Letnes, Paul Anton; Nordam, Tor; Simonsen, Ingve</p> <p>2013-06-01</p> <p>We investigate numerically multiple light-<span class="hlt">scattering</span> phenomena for two-dimensional randomly rough metallic surfaces, where surface plasmon polaritons (SPPs) mediate several surface <span class="hlt">scattering</span> effects. The <span class="hlt">scattering</span> problem is solved by numerical solution of the reduced <span class="hlt">Rayleigh</span> equation for reflection. The multiple <span class="hlt">scattering</span> phenomena of enhanced backscattering and enhanced forward <span class="hlt">scattering</span> are observed in the same system, and their presence is due to the excitation of SPPs. The numerical results discussed are qualitatively different from previous results for one-dimensionally rough surfaces, as one-dimensional surfaces have a limited influence on the polarization of light.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870056742&hterms=taylor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dtaylor','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870056742&hterms=taylor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dtaylor"><span id="translatedtitle">Some observations of a sheared <span class="hlt">Rayleigh</span>-Taylor/Benard instability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Humphrey, J. A. C.; Marcus, D. L.</p> <p>1987-01-01</p> <p>An account is provided of preliminary flow visualization observations made in an unstably stratified flow with shear superimposed. The structures observed appear to be the superposition of a <span class="hlt">Rayleigh</span>-Taylor/Benard instability and a Kelvin-Helmholtz instability. Aside from its intrinsic fundamental value, the study of these structures is of special interest to theoreticians developing nonlinear stability calculation methodologies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..94d5312M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..94d5312M"><span id="translatedtitle"><span class="hlt">Rayleigh</span> waves, surface disorder, and phonon localization in nanostructures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maurer, L. N.; Mei, S.; Knezevic, I.</p> <p>2016-07-01</p> <p>We introduce a technique to calculate thermal conductivity in disordered nanostructures: a finite-difference time-domain solution of the elastic-wave equation combined with the Green-Kubo formula. The technique captures phonon wave behavior and scales well to nanostructures that are too large or too surface disordered to simulate with many other techniques. We investigate the role of <span class="hlt">Rayleigh</span> waves and surface disorder on thermal transport by studying graphenelike nanoribbons with free edges (allowing <span class="hlt">Rayleigh</span> waves) and fixed edges (prohibiting <span class="hlt">Rayleigh</span> waves). We find that free edges result in a significantly lower thermal conductivity than fixed ones. Free edges both introduce <span class="hlt">Rayleigh</span> waves and cause all low-frequency modes (bulk and surface) to become more localized. Increasing surface disorder on free edges draws energy away from the center of the ribbon and toward the disordered edges, where it gets trapped in localized surface modes. These effects are not seen in ribbons with fixed boundary conditions and illustrate the importance of phonon-surface modes in nanostructures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/105871','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/105871"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability experiments in a cylindrically convergent geometry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goodwin, B.; Weir, S.</p> <p>1995-08-25</p> <p>Due to the sensitivity of <span class="hlt">Rayleigh</span>-Taylor instabilities to initial conditions and due to the difficulty of forming well controlled cylindrical or spherical fluid interfaces, <span class="hlt">Rayleigh</span>-Taylor experiments are often performed with simple, planar interfaces. <span class="hlt">Rayleigh</span>-Taylor instability phenomena of practical interest, however, (e.g., underwater explosions, supernova core collapses, and inertial confinement fusion capsule implosions) are typically associated with cylindrical or spherical interfaces in which convergent flow effects have an important influence on the dynamics of instability growth. Recently, Meshkov et.al. have developed a novel technique for studying <span class="hlt">Rayleigh</span>-Taylor instability growth in a cylindrically convergent geometry. Their experiments utilized low-strength gelatin rings which are imploded by a detonating gas mixture of oxygen and acetylene. Since the gelatin itself has sufficient strength to resist significant deformation by gravity, no membranes are needed to define the ring shape. This experimental technique is attractive because it offers a high degree of control over the interfacial geometry and over the material`s strength and rigidity, which can be varied by adjusting the gelatin concentration. Finally, since both the gelatin and the explosive product gases are transparent, optical diagnostics can be used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27415256','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27415256"><span id="translatedtitle">Covariant Lyapunov vectors of chaotic <span class="hlt">Rayleigh</span>-Bénard convection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, M; Paul, M R</p> <p>2016-06-01</p> <p>We explore numerically the high-dimensional spatiotemporal chaos of <span class="hlt">Rayleigh</span>-Bénard convection using covariant Lyapunov vectors. We integrate the three-dimensional and time-dependent Boussinesq equations for a convection layer in a shallow square box geometry with an aspect ratio of 16 for very long times and for a range of <span class="hlt">Rayleigh</span> numbers. We simultaneously integrate many copies of the tangent space equations in order to compute the covariant Lyapunov vectors. The dynamics explored has fractal dimensions of 20≲D_{λ}≲50, and we compute on the order of 150 covariant Lyapunov vectors. We use the covariant Lyapunov vectors to quantify the degree of hyperbolicity of the dynamics and the degree of Oseledets splitting and to explore the temporal and spatial dynamics of the Lyapunov vectors. Our results indicate that the chaotic dynamics of <span class="hlt">Rayleigh</span>-Bénard convection is nonhyperbolic for all of the <span class="hlt">Rayleigh</span> numbers we have explored. Our results yield that the entire spectrum of covariant Lyapunov vectors that we have computed are tangled as indicated by near tangencies with neighboring vectors. A closer look at the spatiotemporal features of the Lyapunov vectors suggests contributions from structures at two different length scales with differing amounts of localization. PMID:27415256</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JFM...453..109J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JFM...453..109J"><span id="translatedtitle"><span class="hlt">Rayleigh</span> Taylor instability of viscoelastic drops at high Weber numbers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joseph, D. D.; Beavers, G. S.; Funada, T.</p> <p>2002-02-01</p> <p>Movies of the breakup of viscous and viscoelastic drops in the high-speed airstream behind a shock wave in a shock tube have been reported by Joseph, Belanger & Beavers (1999). They performed a <span class="hlt">Rayleigh</span> Taylor stability analysis for the initial breakup of a drop of Newtonian liquid and found that the most unstable <span class="hlt">Rayleigh</span> Taylor wave fits nearly perfectly with waves measured on enhanced images of drops from the movies, but the effects of viscosity cannot be neglected. Here we construct a <span class="hlt">Rayleigh</span> Taylor stability analysis for an Oldroyd-B fluid using measured data for acceleration, density, viscosity and relaxation time [lambda]1. The most unstable wave is a sensitive function of the retardation time [lambda]2 which fits experiments when [lambda]2/[lambda]1 = O(10-3). The growth rates for the most unstable wave are much larger than for the comparable viscous drop, which agrees with the surprising fact that the breakup times for viscoelastic drops are shorter. We construct an approximate analysis of <span class="hlt">Rayleigh</span> Taylor instability based on viscoelastic potential flow which gives rise to nearly the same dispersion relation as the unapproximated analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22743466','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22743466"><span id="translatedtitle">Beyond the classical <span class="hlt">Rayleigh</span> limit with twisted light.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tong, Zhisong; Korotkova, Olga</p> <p>2012-07-01</p> <p>It is shown that twisted stochastic light can serve as illumination that may produce images with a resolution overcoming the <span class="hlt">Rayleigh</span> limit by an order of magnitude. This finding is illustrated for an isoplanatic axially symmetric system with low angular aperture and twisted scalar Gaussian Schell-model illumination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvE..93f2208X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvE..93f2208X"><span id="translatedtitle">Covariant Lyapunov vectors of chaotic <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, M.; Paul, M. R.</p> <p>2016-06-01</p> <p>We explore numerically the high-dimensional spatiotemporal chaos of <span class="hlt">Rayleigh</span>-Bénard convection using covariant Lyapunov vectors. We integrate the three-dimensional and time-dependent Boussinesq equations for a convection layer in a shallow square box geometry with an aspect ratio of 16 for very long times and for a range of <span class="hlt">Rayleigh</span> numbers. We simultaneously integrate many copies of the tangent space equations in order to compute the covariant Lyapunov vectors. The dynamics explored has fractal dimensions of 20 ≲Dλ≲50 , and we compute on the order of 150 covariant Lyapunov vectors. We use the covariant Lyapunov vectors to quantify the degree of hyperbolicity of the dynamics and the degree of Oseledets splitting and to explore the temporal and spatial dynamics of the Lyapunov vectors. Our results indicate that the chaotic dynamics of <span class="hlt">Rayleigh</span>-Bénard convection is nonhyperbolic for all of the <span class="hlt">Rayleigh</span> numbers we have explored. Our results yield that the entire spectrum of covariant Lyapunov vectors that we have computed are tangled as indicated by near tangencies with neighboring vectors. A closer look at the spatiotemporal features of the Lyapunov vectors suggests contributions from structures at two different length scales with differing amounts of localization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20717272','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20717272"><span id="translatedtitle">Founding fathers of light <span class="hlt">scattering</span> and surface-enhanced Raman <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kerker, M</p> <p>1991-11-20</p> <p>One can view our comprehension of surface-enhanced Raman <span class="hlt">scattering</span>, particularly that by colloidal dispersions of metal sols, as the merging of two traditions in light-<span class="hlt">scattering</span> theory and practice. One of these originated with Michael Faraday's work on brilliantly colored metal sols, which was taken up by Richard Zsigmondy and then by Gustav Mie, who accounted for the colors by electromagnetic-<span class="hlt">scattering</span> theory. The other tradition starts with John Tyndall's work with aerosols, which stimulated Lord <span class="hlt">Rayleigh</span>'s entry into the field. Lord <span class="hlt">Rayleigh</span> was perplexed by observations made with sulfur hydrosols, which in turn were explored by C. V. Raman. Raman's extensive work in light <span class="hlt">scattering</span> led to his subsequent discovery of the Raman effect. These two traditions were then intertwined when it was shown that the same physical effect that caused Faraday's sols to exhibit their brilliant colors was also the origin of the enhancement of Raman signals from molecules adsorbed on the metal particles that compose these sols.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15263753','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15263753"><span id="translatedtitle">A bent Laue analyser crystal for <span class="hlt">Rayleigh</span>-to-Compton computed tomography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schulze, C; Kleuker, U</p> <p>1998-05-01</p> <p>A new optical system to perform tomography based on the <span class="hlt">Rayleigh</span>-to-Compton (RC) method with high spatial and spectral resolution is presented. The RC technique allows the effective atomic number of a sample to be measured and finds application in bone mineral densitometry in medicine. It is particularly useful for the characterization of the distribution of biological materials which do not exhibit distinctive diffraction peaks. The system is based on the separation of the elastic line from the spectrum that is <span class="hlt">scattered</span> by the sample by means of a bent Laue analyser crystal, and the subsequent independent detection of the elastic and inelastic parts of the spectrum with two large-area scintillation counters. The high energy resolution permits operation at low momentum transfer, where the RC method has its best contrast-to-noise ratio for low-Z materials. The geometrical and spectral requirements in terms of the incident beam and the conical analyser crystal are discussed. A first-generation tomographic imaging system (pencil beam, scanned sample) as implemented at the ESRF Compton-<span class="hlt">Scattering</span> Station ID15B is described. A high-resolution tomographic reconstruction of a bone sample is presented. PMID:15263753</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750014975','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750014975"><span id="translatedtitle">Effect of molecular anisotropy on the intensity and degree of polarization of light <span class="hlt">scattered</span> from model atmospheres</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bahethi, O. P.; Fraser, R. S.</p> <p>1975-01-01</p> <p>Computations of the intensity, flux, degree of polarization, and the positions of neutral points are presented for models of the terrestrial gaseous and hazy atmospheres by incorporating the molecular anisotropy due to air in the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> optical thickness and phase matrix. Molecular anisotropy causes significant changes in the intensity, flux and the degree of polarization of the <span class="hlt">scattered</span> light. The positions of neutral points do not change significantly. When the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> optical thickness is kept constant and the molecular anisotropy factor is included only in the <span class="hlt">Rayleigh</span> phase matrix, the flux does not change and the intensity and positions of neutron points change by a small amount. The changes in the degree of polarization are still significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24663880','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24663880"><span id="translatedtitle">Background clean-up in Brillouin microspectroscopy of <span class="hlt">scattering</span> medium.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meng, Zhaokai; Traverso, Andrew J; Yakovlev, Vladislav V</p> <p>2014-03-10</p> <p>Brillouin spectroscopy is an emerging tool for microscopic optical imaging as it allows for non-contact, non-invasive, direct assessment of the elastic properties of materials. However, strong elastic <span class="hlt">scattering</span> and stray light from various sources often contaminate the Brillouin spectrum. A molecular absorption cell was introduced into the virtually imaged phased array (VIPA) based Brillouin spectroscopy setup to absorb the <span class="hlt">Rayleigh</span> component, which resulted in a substantial improvement of the Brillouin spectrum quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4086329','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4086329"><span id="translatedtitle">Background clean-up in Brillouin microspectroscopy of <span class="hlt">scattering</span> medium</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meng, Zhaokai; Traverso, Andrew J.; Yakovlev, Vladislav V.</p> <p>2014-01-01</p> <p>Brillouin spectroscopy is an emerging tool for microscopic optical imaging as it allows for non-contact, non-invasive, direct assessment of the elastic properties of materials. However, strong elastic <span class="hlt">scattering</span> and stray light from various sources often contaminate the Brillouin spectrum. A molecular absorption cell was introduced into the virtually imaged phased array (VIPA) based Brillouin spectroscopy setup to absorb the <span class="hlt">Rayleigh</span> component, which resulted in a substantial improvement of the Brillouin spectrum quality. PMID:24663880</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22695585','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22695585"><span id="translatedtitle"><span class="hlt">Scattering</span> of light from metamaterial gratings with finite length.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grünhut, Vivian; Cuevas, Mauro; Depine, Ricardo A</p> <p>2012-06-01</p> <p>Using an integral equation approach based on the <span class="hlt">Rayleigh</span> hypothesis, we investigate the <span class="hlt">scattering</span> of a plane wave at the rough surface of a metamaterial with a finite number of sinusoidal grooves. To show the adequacy of the model, we present results that are in agreement with the predictions of physical optics and that quantitatively reproduce the polarization and angular dependences predicted by the C-formalism for metamaterial gratings with an infinite number of grooves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26366662','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26366662"><span id="translatedtitle">Modeling of optical wireless <span class="hlt">scattering</span> communication channels over broad spectra.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Weihao; Zou, Difan; Xu, Zhengyuan</p> <p>2015-03-01</p> <p>The air molecules and suspended aerosols help to build non-line-of-sight (NLOS) optical <span class="hlt">scattering</span> communication links using carriers from near infrared to visible light and ultraviolet bands. This paper proposes channel models over such broad spectra. Wavelength dependent <span class="hlt">Rayleigh</span> and Mie <span class="hlt">scattering</span> and absorption coefficients of particles are analytically obtained first. They are applied to the ray tracing based Monte Carlo method, which models the photon <span class="hlt">scattering</span> angle from the <span class="hlt">scatterer</span> and propagation distance between two consecutive <span class="hlt">scatterers</span>. Communication link path loss is studied under different operation conditions, including visibility, particle density, wavelength, and communication range. It is observed that optimum communication performances exist across the wavelength under specific atmospheric conditions. Infrared, visible light and ultraviolet bands show their respective features as conditions vary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15013215','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15013215"><span id="translatedtitle">Dense Matter Characterization by X-ray Thomson <span class="hlt">Scattering</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Landen, O L; Glenzer, S H; Edwards, M J; Lee, R W; Collins, G W; Cauble, R C; Hsing, W W; Hammel, B A</p> <p>2000-12-29</p> <p>We discuss the extension of the powerful technique of Thomson <span class="hlt">scattering</span> to the x-ray regime for providing an independent measure of plasma parameters for dense plasmas. By spectrally-resolving the <span class="hlt">scattering</span>, the coherent (<span class="hlt">Rayleigh</span>) unshifted <span class="hlt">scattering</span> component can be separated from the incoherent Thomson component, which is both Compton and Doppler shifted. The free electron density and temperature can then be inferred from the spectral shape of the high frequency Thomson <span class="hlt">scattering</span> component. In addition, as the plasma temperature is decreased, the electron velocity distribution as measured by incoherent Thomson <span class="hlt">scattering</span> will make a transition from the traditional Gaussian Boltzmann distribution to a density-dependent parabolic Fermi distribution to. We also present a discussion for a proof-of-principle experiment appropriate for a high energy laser facility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007APS..DPPPP8138L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007APS..DPPPP8138L&link_type=ABSTRACT"><span id="translatedtitle">Thomson <span class="hlt">Scattering</span> on the HBT-EP Tokamak</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levesque, J. P.; Litzner, K. D.; Hanson, J. M.; James, R.; Maurer, D. A.; Mauel, M. E.; Navratil, G. A.; Pedersen, T. S.</p> <p>2007-11-01</p> <p>Thomson <span class="hlt">scattering</span> can be used as a non-invasive method for measuring local electron density and temperature in plasmas. We describe the HBT-EP Thomson <span class="hlt">Scattering</span> diagnostic, which is based on a design in use at DIII-D [1]. A five-channel interference filter polychrometer measures incoherent <span class="hlt">scattered</span> light from an 8ns, 800mJ, 1064nm Nd:YAG laser pulse. A set of pre-amplification circuits designed by Princeton Scientific Instruments [2] has recently been installed for signal detection using avalanche photodiodes. System layout, alignment, and straylight level reduction techniques will be outlined. <span class="hlt">Rayleigh</span> and Raman <span class="hlt">scattering</span> calibration procedures have been used to absolutely calibrate the collection optics and detection system. Recent progress on diagnosing different HBT-EP plasmas using the Thomson <span class="hlt">scattering</span> diagnostic will be presented. [1] T. N. Carlstrom, et al, Rev. Sci. Instr. 61, 2858, 1990. [2] D. Johnson, et al, Rev. Sci. Instr. 72, 1, 1129, 2001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910012142','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910012142"><span id="translatedtitle">Singularities in water waves and <span class="hlt">Rayleigh</span>-Taylor instability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tanveer, S.</p> <p>1991-01-01</p> <p>Singularities in inviscid two-dimensional finite-amplitude water waves and inviscid <span class="hlt">Rayleigh</span>-Taylor instability are discussed. For the deep water gravity waves of permanent form, through a combination of analytical and numerical methods, results describing the precise form, number, and location of singularities in the unphysical domain as the wave height is increased are presented. It is shown how the information on the singularity in the unphysical region has the same form as for deep water waves. However, associated with such a singularity is a series of image singularities at increasing distances from the physical plane with possibly different behavior. Furthermore, for the <span class="hlt">Rayleigh</span>-Taylor problem of motion of fluid over a vacuum and for the unsteady water wave problem, integro-differential equations valid in the unphysical region are derived, and how these equations can give information on the nature of singularities for arbitrary initial conditions is shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DFD.D2002A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DFD.D2002A"><span id="translatedtitle">Logarithmic temperature profiles in turbulent <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahlers, Guenter; He, Xiaozhou; Funfschilling, Denis; van Gils, Dennis; Bodenschatz, Eberhard</p> <p>2012-11-01</p> <p>We report experimental results for the vertical profiles of the mean temperature < T > and the rms temperature fluctuation σ for turbulent <span class="hlt">Rayleigh</span>-Bénard convection in the interior of a cylindrical sample of aspect ratio Γ ≡ D / L = 0 . 50 (D = 112 cm and L = 224 cm are the diameter and height respectively) over the <span class="hlt">Rayleigh</span> number range 4 ×1012 <= Ra <=1015 for a Prandtl number Pr ~= 0 . 8 . We found that < T > and σ vary linearly with ln (z / L) where z is the distance from the bottom or top plate. Such a dependence had been predicted for the ultimate state (Ra > 5 ×1014), but was unexpected for the classical state (Ra <1013). The results for < T > and σ suggest similarities to the logarithmic profiles found for the velocity in shear flows. Supported by the Max Planck Society, the Volkswagen Stiftung, the DFD Sonderforschungsbereich SFB963, and NSF grant DMR11-58514.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OptEn..53f1607H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OptEn..53f1607H"><span id="translatedtitle">Analysis on wind retrieval methods for <span class="hlt">Rayleigh</span> Doppler lidar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Yuli; Dou, Xiankang; Sun, Dongsong; Xia, Haiyun; Shu, Zhifeng</p> <p>2014-06-01</p> <p>A modification method is described for <span class="hlt">Rayleigh</span> Doppler lidar wind retrieval. Compared to the double-edge theory of Korb et al. [Appl. Opt., 38, 432 (1999)] and the retrieval algorithm of Chanin et al. [Geophys. Res. Lett., 16, 1273 (1989)], it has a greater sensitivity. The signal-to-noise ratio of the energy monitor channel is involved in error estimation. When the splitting ratio of the two signal channels is 1.2, which usually happened during wind detection, it will improve the measurement accuracy by about 1% at 30 km altitude for a Doppler shift of 250 MHz (44 m/s). Stabilities of retrieval methods, i.e., errors caused by the spectrum width deviation including laser pulse, <span class="hlt">Rayleigh</span> backscatter, and filter transmission curve are first discussed. The proposed method increases the resultant precision by about 15% at 30-km altitude assuming an 8-MHz deviation in full width at half maximum of the Fabry-Perot interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870019259&hterms=Crowding&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCrowding','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870019259&hterms=Crowding&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCrowding"><span id="translatedtitle">Boundary effects on Marangoni-<span class="hlt">Rayleigh</span> and morphological instabilities</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Narayanan, R.</p> <p>1987-01-01</p> <p>Effects of boundaries (vertical sides) on the Marangoni-<span class="hlt">Rayleigh</span> problem are reviewed. Spectral crowding and a dimensional singularity when <span class="hlt">Rayleigh</span> effects are neglected are discussed. In the unbounded case, there is a unique Ma with unique eigenfunction for fixed Ra but infinite Ra for fixed Ma. These infinite values of Ra correspond to vertical cellular modes. In the bounded case, there is infinite Ma for a fixed Ra. The stress free side wall case gives double infinite of Ra for fixed Ma and wave number. Clearly, a dimensional singularity occurs for the Marangoni problem when the side walls go to infinity and a fixed Ra is considered. There is no direct analogy regarding this singularity in the morphological instability problem. Results on the behavior of Mac, Rac with boundary conditions also show only marginal connection to the morphological stability problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDM19003V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDM19003V"><span id="translatedtitle">Plume emission statistics in turbulent <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Poel, Erwin; Verzicco, Roberto; Grossmann, Siegfried; Lohse, Detlef</p> <p>2014-11-01</p> <p><span class="hlt">Rayleigh</span>-Benard convection features ubiquitous coherent structures, which continue to survive in strong turbulence. The most prevalent are the thermal plumes and the large scale circulation (LSC). The thermal plumes and the LSC are intrinsically coupled, as thermal plumes cluster to form a LSC. We report statistics of the area, width and location of plumes extracted from high <span class="hlt">Rayleigh</span> number (Ra <=1012) direct numerical simulations in a cylindrical domain of aspect-ratio 0 . 33 . While the area of the plume is unimodally distributed close to the plates, far from the plates plume clustering results in a bimodal distribution. In addition, the analysis reveals that more plumes are emitted from areas with low shear as compared to areas with high shear.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033330','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033330"><span id="translatedtitle">Joint inversion of fundamental and higher mode <span class="hlt">Rayleigh</span> waves</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Luo, Y.-H.; Xia, J.-H.; Liu, J.-P.; Liu, Q.-S.</p> <p>2008-01-01</p> <p>In this paper, we analyze the characteristics of the phase velocity of fundamental and higher mode <span class="hlt">Rayleigh</span> waves in a six-layer earth model. The results show that fundamental mode is more sensitive to the shear velocities of shallow layers (< 7 m) and concentrated in a very narrow band (around 18 Hz) while higher modes are more sensitive to the parameters of relatively deeper layers and distributed over a wider frequency band. These properties provide a foundation of using a multi-mode joint inversion to define S-wave velocity. Inversion results of both synthetic data and a real-world example demonstrate that joint inversion with the damped least squares method and the SVD (Singular Value Decomposition) technique to invert <span class="hlt">Rayleigh</span> waves of fundamental and higher modes can effectively reduce the ambiguity and improve the accuracy of inverted S-wave velocities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991rtic.conf....4R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991rtic.conf....4R"><span id="translatedtitle">Large growth <span class="hlt">Rayleigh</span>-Taylor experiments on Nova</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Remington, B. A.; Haan, S. W.; Glendinning, S. G.; Kilkenny, J. D.; Munro, D. H.; Wallace, R. J.</p> <p>1991-01-01</p> <p>Large growth <span class="hlt">Rayleigh</span>-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of fluorosilicone foils with 50 micron wavelength initial surface perturbations. Foils with very small amplitude initial perturbations grow exponentially for much longer, and show growth factors of up to 60. From comparisons with 2-dimensional computer simulations, we estimate that the growth rate is approximately 60 percent of classical, the reduction attributed to ablative and gradient scale length stabilization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5569626','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5569626"><span id="translatedtitle">Large growth <span class="hlt">Rayleigh</span>-Taylor experiments on Nova</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Remington, B.A.; Haan, S.W.; Glendinning, S.G.; Kilkenny, J.D.; Munro, D.H.; Wallace, R.J.</p> <p>1991-01-22</p> <p>Large growth <span class="hlt">Rayleigh</span>-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of fluorosilicone foils with 50 {mu}m wavelength initial surface perturbations. Foils with very small amplitude initial perturbations grow exponentially for much longer, and show growth factors of up to 60. From comparisons with 2-dimensional computer simulations, we estimate that the growth rate is approximately 60% of classical, the reduction attributed to ablative and gradient scale length stabilization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760004702','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760004702"><span id="translatedtitle">Distribution and moments of radial error. [<span class="hlt">Rayleigh</span> distribution - random variables</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>White, R. G.</p> <p>1975-01-01</p> <p>An investigation of the moments and probability distribution of the resultant of two normally distributed random variables is presented. This is the so-called generalized <span class="hlt">Rayleigh</span> distribution which has many applications in the study of wind shear, random noise, and radar. The most general formula was derived, and two special cases were considered for which tables of the moments and probability distribution functions are included as an appendix. One of the special cases was generalized to n-dimensions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032055','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032055"><span id="translatedtitle">Sensitivity of high-frequency <span class="hlt">Rayleigh</span>-wave data revisited</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xia, J.; Miller, R.D.; Ivanov, J.</p> <p>2007-01-01</p> <p><span class="hlt">Rayleigh</span>-wave phase velocity of a layered earth model is a function of frequency and four groups of earth properties: P-wave velocity, S-wave velocity (Vs), density, and thickness of layers. Analysis of the Jacobian matrix (or the difference method) provides a measure of dispersion curve sensitivity to earth properties. Vs is the dominant influence for the fundamental mode (Xia et al., 1999) and higher modes (Xia et al., 2003) of dispersion curves in a high frequency range (>2 Hz) followed by layer thickness. These characteristics are the foundation of determining S-wave velocities by inversion of <span class="hlt">Rayleigh</span>-wave data. More applications of surface-wave techniques show an anomalous velocity layer such as a high-velocity layer (HVL) or a low-velocity layer (LVL) commonly exists in near-surface materials. Spatial location (depth) of an anomalous layer is usually the most important information that surface-wave techniques are asked to provide. Understanding and correctly defining the sensitivity of high-frequency <span class="hlt">Rayleigh</span>-wave data due to depth of an anomalous velocity layer are crucial in applying surface-wave techniques to obtain a Vs profile and/or determine the depth of an anomalous layer. Because depth is not a direct earth property of a layered model, changes in depth will result in changes in other properties. Modeling results show that sensitivity at a given depth calculated by the difference method is dependent on the Vs difference (contrast) between an anomalous layer and surrounding layers. The larger the contrast is, the higher the sensitivity due to depth of the layer. Therefore, the Vs contrast is a dominant contributor to sensitivity of <span class="hlt">Rayleigh</span>-wave data due to depth of an anomalous layer. Modeling results also suggest that the most sensitive depth for an HVL is at about the middle of the depth to the half-space, but for an LVL it is near the ground surface. ?? 2007 Society of Exploration Geophysicists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20366649','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20366649"><span id="translatedtitle">Nonlinear diffusion model for <span class="hlt">Rayleigh</span>-Taylor mixing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boffetta, G; De Lillo, F; Musacchio, S</p> <p>2010-01-22</p> <p>The complex evolution of turbulent mixing in <span class="hlt">Rayleigh</span>-Taylor convection is studied in terms of eddy diffusivity models for the mean temperature profile. It is found that a nonlinear model, derived within the general framework of Prandtl mixing theory, reproduces accurately the evolution of turbulent profiles obtained from numerical simulations. Our model allows us to give very precise predictions for the turbulent heat flux and for the Nusselt number in the ultimate state regime of thermal convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNP...780..167S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNP...780..167S"><span id="translatedtitle">The <span class="hlt">Rayleigh</span>-Ritz Technique for Estimating Eigenvalues</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schnack, Dalton D.</p> <p></p> <p>The energy principle provides a powerful technique for determining the stability or instability of a magneto-fluid system without resorting to the solution of a differential equation. Instead, one makes an educated guess at the minimizing displacement and then examines the sign of the resulting eigenvalue. This approach is made even more powerful, and put on a solid theoretical footing, by application of the <span class="hlt">Rayleigh</span>-Ritz technique for estimating the eigenvalues of a self-adjoint operator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22303432','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22303432"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability in an equal mass plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Adak, Ashish; Ghosh, Samiran; Chakrabarti, Nikhil</p> <p>2014-09-15</p> <p>The <span class="hlt">Rayleigh</span>-Taylor (RT) instability in an inhomogeneous pair-ion plasma has been analyzed. Considering two fluid model for two species of ions (positive and negative), we obtain the possibility of the existence of RT instability. The growth rate of the RT instability as usual depends on gravity and density gradient scale length. The results are discussed in context of pair-ion plasma experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1240972-viscous-rayleigh-taylor-instability-spherical-geometry','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1240972-viscous-rayleigh-taylor-instability-spherical-geometry"><span id="translatedtitle">Viscous <span class="hlt">Rayleigh</span>-Taylor instability in spherical geometry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Mikaelian, Karnig O.</p> <p>2016-02-08</p> <p>We consider viscous fluids in spherical geometry, a lighter fluid supporting a heavier one. Chandrasekhar [Q. J. Mech. Appl. Math. 8, 1 (1955)] analyzed this unstable configuration providing the equations needed to find, numerically, the exact growth rates for the ensuing <span class="hlt">Rayleigh</span>-Taylor instability. He also derived an analytic but approximate solution. We point out a weakness in his approximate dispersion relation (DR) and offer one that is to some extent improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408389','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408389"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor vortices in a pair-ion plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Adak, Ashish Khan, Manoranjan</p> <p>2015-04-15</p> <p>The <span class="hlt">Rayleigh</span>-Taylor (RT) vortices and the analytical solution of three-mode coupling in pair-ion plasmas are investigated. It is shown that the E×B convection of polarization drift is responsible for the saturation of growing RT instability and as a result the localized dipole vortex structures are formed. The shear flow generation due to the destruction of vortex structures is discussed by the Fourier mode analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22039917','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039917"><span id="translatedtitle">Measurement of magnetic field using <span class="hlt">Rayleigh</span> backscattering in optical fibres</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wuilpart, M.; Caucheteur, C.; Goussarov, A.; Aerssens, M.; Massaut, V.; Megret, P.</p> <p>2011-07-01</p> <p>In this paper, we investigate the use of optical reflectometry in optical fibres for the measurement of magnetic field. The dedicated application concerns the measurement of plasma current in the fusion reactor. The measurement is based on the rotation of the polarization state of the <span class="hlt">Rayleigh</span> backscattered signal when an optical pulse is launched in the fibre. Particular care has been undertaken to evaluate the impact of linear birefringence on the measurement performance. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490103','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490103"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability in dusty plasma experiment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Avinash, K.; Sen, A.</p> <p>2015-08-15</p> <p>The stability of a stratified dust cloud levitated in an anodic plasma is studied in the weakly and strongly coupled dust regimes. It is shown that the cloud is predominantly unstable to a <span class="hlt">Rayleigh</span>-Taylor (RT) instability driven by a component of the ambient gravity in a direction opposite to the direction of dust density stratification in the cloud. The elasticity of the strongly coupled dust is shown to set a threshold for the RT instability, which is consistent with experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22h3707A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22h3707A"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability in dusty plasma experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Avinash, K.; Sen, A.</p> <p>2015-08-01</p> <p>The stability of a stratified dust cloud levitated in an anodic plasma is studied in the weakly and strongly coupled dust regimes. It is shown that the cloud is predominantly unstable to a <span class="hlt">Rayleigh</span>-Taylor (RT) instability driven by a component of the ambient gravity in a direction opposite to the direction of dust density stratification in the cloud. The elasticity of the strongly coupled dust is shown to set a threshold for the RT instability, which is consistent with experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034583','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034583"><span id="translatedtitle">Dipping-interface mapping using mode-separated <span class="hlt">Rayleigh</span> waves</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Luo, Y.; Xia, J.; Xu, Y.; Zeng, C.; Miller, R.D.; Liu, Q.</p> <p>2009-01-01</p> <p>Multichannel analysis of surface waves (MASW) method is a non-invasive geophysical technique that uses the dispersive characteristic of <span class="hlt">Rayleigh</span> waves to estimate a vertical shear (S)-wave velocity profile. A pseudo-2D S-wave velocity section is constructed by aligning 1D S-wave velocity profiles at the midpoint of each receiver spread that are contoured using a spatial interpolation scheme. The horizontal resolution of the section is therefore most influenced by the receiver spread length and the source interval. Based on the assumption that a dipping-layer model can be regarded as stepped flat layers, high-resolution linear Radon transform (LRT) has been proposed to image <span class="hlt">Rayleigh</span>-wave dispersive energy and separate modes of <span class="hlt">Rayleigh</span> waves from a multichannel record. With the mode-separation technique, therefore, a dispersion curve that possesses satisfactory accuracy can be calculated using a pair of consecutive traces within a mode-separated shot gather. In this study, using synthetic models containing a dipping layer with a slope of 5, 10, 15, 20, or 30 degrees and a real-world example, we assess the ability of using high-resolution LRT to image and separate fundamental-mode <span class="hlt">Rayleigh</span> waves from raw surface-wave data and accuracy of dispersion curves generated by a pair of consecutive traces within a mode-separated shot gather. Results of synthetic and real-world examples demonstrate that a dipping interface with a slope smaller than 15 degrees can be successfully mapped by separated fundamental waves using high-resolution LRT. ?? Birkh??user Verlag, Basel 2009.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995JAP....78.5577S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995JAP....78.5577S&link_type=ABSTRACT"><span id="translatedtitle">Anomalous shape of magnetic loops in the <span class="hlt">Rayleigh</span> region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seeck, St.; Lambeck, M.</p> <p>1995-11-01</p> <p>According to its congruency property, the Preisach model demands an equivalent shape of magnetic minor loops, the so-called <span class="hlt">Rayleigh</span> loops. We measured these loops with an inductive setup and noticed a different anomalous shape of <span class="hlt">Rayleigh</span> loops which depends on the magnetic history. Special materials (particularly recording media) show a concave-convex shape in contrast to the normal biconvex shape. This anomalous shape can be explained by combining the Preisach model with the Stoner-Wohlfarth model. It follows from this explanation that the degree of the anomaly depends on the material, especially in how far it fulfills the conditions of the Stoner-Wohlfarth model. The experiments show the effect that is expected according to the material. In this way the measurement of the anomalous <span class="hlt">Rayleigh</span> loops can be used as a new method to test the Stoner-Wohlfarth properties of a material. This is more effective than using the Henkel plot [G. Bertotti and V. Basso, J. Appl. Phys. 73, 5827 (1993)].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/834430','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/834430"><span id="translatedtitle">Model studies of <span class="hlt">Rayleigh</span> instabilities via microdesigned interfaces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Glaeser, Andreas M.</p> <p>2000-10-17</p> <p>The energetic and kinetic properties of surfaces play a critical role in defining the microstructural changes that occur during sintering and high-temperature use of ceramics. Characterization of surface diffusion in ceramics is particularly difficult, and significant variations in reported values of surface diffusivities arise even in well-studied systems. Effects of impurities, surface energy anisotropy, and the onset of surface attachment limited kinetics (SALK) are believed to contribute to this variability. An overview of the use of <span class="hlt">Rayleigh</span> instabilities as a means of characterizing surface diffusivities is presented. The development of models of morphological evolution that account for effects of surface energy anisotropy is reviewed, and the potential interplay between impurities and surface energy anisotropy is addressed. The status of experimental studies of <span class="hlt">Rayleigh</span> instabilities in sapphire utilizing lithographically introduced pore channels of controlled geometry and crystallography is summarized. Results of model studies indicate that impurities can significantly influence both the spatial and temporal characteristics of <span class="hlt">Rayleigh</span> instabilities; this is attributed at least in part to impurity effects on the surface energy anisotropy. Related model experiments indicate that the onset of SALK may also contribute significantly to apparent variations in surface diffusion coefficients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890004884','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890004884"><span id="translatedtitle">Leakage predictions for <span class="hlt">Rayleigh</span>-step, helium-purge seals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Proctor, Margaret P.</p> <p>1988-01-01</p> <p><span class="hlt">Rayleigh</span>-step, helium purge, annular shaft seals, studied for use in liquid oxygen turbopumps, generate a hydrodynamic force that enables the seal to follow shaft perturbations. Hence, smaller clearances can be used to reduce seal leakage. FLOWCAL, a computer code developed by Mechanical Technology Incorporated, predicts gas flow rate through an annular seal with an axial pressure gradient. Analysis of a 50-mm <span class="hlt">Rayleigh</span>-step, helium-purge, annular seal showed the flow rate increased axial pressure gradient, downstream pressure, and eccentricity ratio. Increased inlet temperature reduced leakage. Predictions made at maximum and minimum clearances (due to centrifugal and thermal growths, machining tolerances and + or - 2 percent uncertainty in the clearance measurement) placed wide boundaries on expected flow rates. The widest boundaries were set by thermal growth conditions. Predicted flow rates for a 50-mm <span class="hlt">Rayleigh</span>-step, helium-purge, annular seal underestimated measured flow rates by three to seven times. However, the analysis did accurately predict flow rates for choked gas flow through annular seals when compared to flow rates measured in two other independent studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4919638','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4919638"><span id="translatedtitle">Cloaking of solar cell contacts at the onset of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M.; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S. R. J.; Ripalda, José M.</p> <p>2016-01-01</p> <p>Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow. PMID:27339390</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...628669S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...628669S"><span id="translatedtitle">Cloaking of solar cell contacts at the onset of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M.; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S. R. J.; Ripalda, José M.</p> <p>2016-06-01</p> <p>Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27339390','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27339390"><span id="translatedtitle">Cloaking of solar cell contacts at the onset of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S R J; Ripalda, José M</p> <p>2016-01-01</p> <p>Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27339390','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27339390"><span id="translatedtitle">Cloaking of solar cell contacts at the onset of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>San Román, Etor; Vitrey, Alan; Buencuerpo, Jerónimo; Prieto, Iván; Llorens, José M; García-Martín, Antonio; Alén, Benito; Chaudhuri, Anabil; Neumann, Alexander; Brueck, S R J; Ripalda, José M</p> <p>2016-01-01</p> <p>Electrical contacts on the top surface of solar cells and light emitting diodes cause shadow losses. The phenomenon of extraordinary optical transmission through arrays of subwavelength holes suggests the possibility of engineering such contacts to reduce the shadow using plasmonics, but resonance effects occur only at specific wavelengths. Here we describe instead a broadband effect of enhanced light transmission through arrays of subwavelength metallic wires, due to the fact that, in the absence of resonances, metal wires asymptotically tend to invisibility in the small size limit regardless of the fraction of the device area taken up by the contacts. The effect occurs for wires more than an order of magnitude thicker than the transparency limit for metal thin films. Finite difference in time domain calculations predict that it is possible to have high cloaking efficiencies in a broadband wavelength range, and we experimentally demonstrate contact shadow losses less than half of the geometric shadow. PMID:27339390</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010070990','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010070990"><span id="translatedtitle"><span class="hlt">Scattering</span> by Randomly Oriented Thin Ice Disks with Moderate Equivalent-Sphere Size Parameters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zakharova, Nadia T.; Mishchenko, Michael I.; Hansen, James E. (Technical Monitor)</p> <p>2001-01-01</p> <p>We use the T-matrix method to compute the <span class="hlt">scattering</span> matrix for randomly oriented circular ice cylinders with diameter-to-length ratios 1 and 20 and surface-equivalent-sphere size parameters up to 12. We show that wavelength-sized, sharp-edged ice plates with extreme diameter-to-length ratios possess the same <span class="hlt">scattering</span> properties as smooth plate-like spheroids: their phase functions are similar to those of surface-equivalent compact particles, whereas all other elements of the <span class="hlt">scattering</span> matrix are typical of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhRvL..87j3902Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhRvL..87j3902Y"><span id="translatedtitle">Angle-Resolved Second-Harmonic Light <span class="hlt">Scattering</span> from Colloidal Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, N.; Angerer, W. E.; Yodh, A. G.</p> <p>2001-09-01</p> <p>We report angle-resolved second-harmonic generation (SHG) measurements from suspensions of centrosymmetric micron-size polystyrene spheres with surface-adsorbed dye (malachite green). The second-harmonic <span class="hlt">scattering</span> profiles differ qualitatively from linear light <span class="hlt">scattering</span> profiles of the same particles. We investigated these radiation patterns using several polarization configurations and particle diameters. We introduce a simple <span class="hlt">Rayleigh</span>-Gans-Debye model to account for the SHG <span class="hlt">scattering</span> anisotropy. The model compares favorably with our experimental data. Our measurements suggest <span class="hlt">scattering</span> anisotropy may be used to isolate particle nonlinear optics from other bulk nonlinear optical effects in suspension.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5356050','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5356050"><span id="translatedtitle">Application of 30-MHz acoustic <span class="hlt">scattering</span> to the study of human red blood cells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roos, M.S.; Apfel, R.E.; Wardlaw, S.C.</p> <p>1988-04-01</p> <p>A technique for simultaneously measuring the <span class="hlt">scattering</span> amplitude of individual particles at two angles is applied to human red blood cells. Using a <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> model, the density and compressibility of the cells may be determined given a priori knowledge of their volume. A calibration method relying on measurements of the bulk properties of particle suspensions is described. Red cell properties in hypotonic and hypertonic hosts are compared with a homogeneous mixture model, and a linear relation between hemoglobin content and <span class="hlt">scattering</span> amplitude at a 90 deg <span class="hlt">scattering</span> angle is established.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/40277519','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/40277519"><span id="translatedtitle">Angle-Resolved Second-Harmonic Light <span class="hlt">Scattering</span> from Colloidal Particles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang, N.; Angerer, W. E.; Yodh, A. G.</p> <p>2001-09-03</p> <p>We report angle-resolved second-harmonic generation (SHG) measurements from suspensions of centrosymmetric micron-size polystyrene spheres with surface-adsorbed dye (malachite green). The second-harmonic <span class="hlt">scattering</span> profiles differ qualitatively from linear light <span class="hlt">scattering</span> profiles of the same particles. We investigated these radiation patterns using several polarization configurations and particle diameters. We introduce a simple <span class="hlt">Rayleigh</span>-Gans-Debye model to account for the SHG <span class="hlt">scattering</span> anisotropy. The model compares favorably with our experimental data. Our measurements suggest <span class="hlt">scattering</span> anisotropy may be used to isolate particle nonlinear optics from other bulk nonlinear optical effects in suspension.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JCoPh.315..536B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JCoPh.315..536B"><span id="translatedtitle">Nonlinear Laplacian spectral analysis of <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brenowitz, N. D.; Giannakis, D.; Majda, A. J.</p> <p>2016-06-01</p> <p>The analysis of physical datasets using modern methods developed in machine learning presents unique challenges and opportunities. These datasets typically feature many degrees of freedom, which tends to increase the computational cost of statistical methods and complicate interpretation. In addition, physical systems frequently exhibit a high degree of symmetry that should be exploited by any data analysis technique. The classic problem of <span class="hlt">Rayleigh</span> Benárd convection in a periodic domain is an example of such a physical system with trivial symmetries. This article presents a technique for analyzing the time variability of numerical simulations of two-dimensional <span class="hlt">Rayleigh</span>-Bénard convection at large aspect ratio and intermediate <span class="hlt">Rayleigh</span> number. The simulated dynamics are highly unsteady and consist of several convective rolls that are distributed across the domain and oscillate with a preferred frequency. Intermittent extreme events in the net heat transfer, as quantified by the time-weighted probability distribution function of the Nusselt number, are a hallmark of these simulations. Nonlinear Laplacian Spectral Analysis (NLSA) is a data-driven method which is ideally suited for the study of such highly nonlinear and intermittent dynamics, but the trivial symmetries of the <span class="hlt">Rayleigh</span>-Bénard problem such as horizontal shift-invariance can mask the interesting dynamics. To overcome this issue, the vertical velocity is averaged over parcels of similar temperature and height, which substantially compresses the size of the dataset and removes trivial horizontal symmetries. This isothermally averaged dataset, which is shown to preserve the net convective heat-flux across horizontal surfaces, is then used as an input to NLSA. The analysis generates a small number of orthogonal modes which describe the spatiotemporal variability of the heat transfer. A regression analysis shows that the extreme events of the net heat transfer are primarily associated with a family of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21352400','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21352400"><span id="translatedtitle">High-order momentum modes by resonant superradiant <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou Xiaoji; Fu Jiageng; Chen Xuzong</p> <p>2009-12-15</p> <p>The spatial and time evolutions of superradiant <span class="hlt">scattering</span> are studied theoretically for a weak pump beam with different frequency components traveling along the long axis of an elongated Bose-Einstein condensate. Resulting from the analysis for mode competition between the different resonant channels and the local depletion of the spatial distribution in the superradiant <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, a method of getting a large number of high-order forward modes by resonant frequency components of the pump beam is provided, which is beneficial to a lager momentum transfer in atom manipulation for the atom interferometry and atomic optics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27479229','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27479229"><span id="translatedtitle">Spin reversal and orbital torques on a viscous fluid <span class="hlt">Rayleigh</span> sphere located arbitrarily in acoustical Bessel vortex (spiraling) beams.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mitri, F G</p> <p>2016-12-01</p> <p>The goal of this work is to demonstrate the emergence of a spin torque singularity (i.e. zero spin torque) and a spin rotation reversal of a small <span class="hlt">Rayleigh</span> lipid/fat viscous fluid sphere located arbitrarily in space in the field of an acoustical Bessel vortex beam. This counter-intuitive property of negative spin torque generation suggests a direction of spin rotation in opposite handedness of the angular momentum carried by the incident beam. Such effects may open new capabilities in methods of quantitative characterization to determine physical properties such as viscosity, viscoelasticity, compressibility, stiffness, etc., and other techniques for the rotation and positioning using acoustical tractor beams and tweezers, invisibility cloaks, and acoustically-engineered composite metamaterials to name a few examples. Based on the descriptions for the velocity potential of the incident beam and the <span class="hlt">scattering</span> coefficients of the sphere in the long-wavelength approximation limit, simplified expressions for the spin and orbital radiation torque components are derived. For beams with (positive or negative) unit topological charge (m=±1), the axial spin torque component for a <span class="hlt">Rayleigh</span> absorptive sphere is maximal at the center of the beam, while it vanishes for |m|>1 therein. Moreover, the longitudinal orbital torque component, causing the sphere to rotate around the center of the beam is evaluated based on the mathematical decomposition using the gradient, <span class="hlt">scattering</span> and absorption transverse radiation force vector components. It is shown that there is no contribution of the gradient transverse force to the orbital torque, which is only caused by the <span class="hlt">scattering</span> and absorption transverse force components. Though the incident acoustical vortex beam carrying angular momentum causes the sphere to rotate in the same orbital direction of the beam handedness, it induces a spin torque singularity (i.e. zero spin torque) and subsequent sign reversal. This phenomenon of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27479229','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27479229"><span id="translatedtitle">Spin reversal and orbital torques on a viscous fluid <span class="hlt">Rayleigh</span> sphere located arbitrarily in acoustical Bessel vortex (spiraling) beams.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mitri, F G</p> <p>2016-12-01</p> <p>The goal of this work is to demonstrate the emergence of a spin torque singularity (i.e. zero spin torque) and a spin rotation reversal of a small <span class="hlt">Rayleigh</span> lipid/fat viscous fluid sphere located arbitrarily in space in the field of an acoustical Bessel vortex beam. This counter-intuitive property of negative spin torque generation suggests a direction of spin rotation in opposite handedness of the angular momentum carried by the incident beam. Such effects may open new capabilities in methods of quantitative characterization to determine physical properties such as viscosity, viscoelasticity, compressibility, stiffness, etc., and other techniques for the rotation and positioning using acoustical tractor beams and tweezers, invisibility cloaks, and acoustically-engineered composite metamaterials to name a few examples. Based on the descriptions for the velocity potential of the incident beam and the <span class="hlt">scattering</span> coefficients of the sphere in the long-wavelength approximation limit, simplified expressions for the spin and orbital radiation torque components are derived. For beams with (positive or negative) unit topological charge (m=±1), the axial spin torque component for a <span class="hlt">Rayleigh</span> absorptive sphere is maximal at the center of the beam, while it vanishes for |m|>1 therein. Moreover, the longitudinal orbital torque component, causing the sphere to rotate around the center of the beam is evaluated based on the mathematical decomposition using the gradient, <span class="hlt">scattering</span> and absorption transverse radiation force vector components. It is shown that there is no contribution of the gradient transverse force to the orbital torque, which is only caused by the <span class="hlt">scattering</span> and absorption transverse force components. Though the incident acoustical vortex beam carrying angular momentum causes the sphere to rotate in the same orbital direction of the beam handedness, it induces a spin torque singularity (i.e. zero spin torque) and subsequent sign reversal. This phenomenon of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvB..93x1302S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvB..93x1302S&link_type=ABSTRACT"><span id="translatedtitle">Measurement of spin coherence using Raman <span class="hlt">scattering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Z.; Delteil, A.; Faelt, S.; Imamoǧlu, A.</p> <p>2016-06-01</p> <p>Ramsey interferometry provides a natural way to determine the coherence time of most qubit systems. Recent experiments on quantum dots, however, demonstrated that dynamical nuclear spin polarization can strongly influence the measurement process, making it difficult to extract the T2* coherence time using standard optical Ramsey pulses. Here, we demonstrate an alternative method for spin coherence measurement that is based on first-order coherence of photons generated in spin-flip Raman <span class="hlt">scattering</span>. We show that if a quantum emitter is driven by a weak monochromatic laser, Raman coherence is determined exclusively by spin coherence, allowing for a direct determination of spin T2* time. When combined with coherence measurements on <span class="hlt">Rayleigh</span> <span class="hlt">scattered</span> photons, our technique enables us to identify coherent and incoherent contributions to resonance fluorescence, and to minimize the latter. We verify the validity of our technique by comparing our results to those determined from Ramsey interferometry for electron and heavy-hole spins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030066422&hterms=nanoparticle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnanoparticle','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030066422&hterms=nanoparticle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnanoparticle"><span id="translatedtitle">A Theoretical Light <span class="hlt">Scattering</span> Model of Nanoparticle Laser Tweezers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lock, James A.</p> <p>2003-01-01</p> <p>Accomplishments this reporting period include: 1. derived, programmed, checked, and tested the Mie light <span class="hlt">scattering</span> theory formulas for the radiation trapping force for both the on-axis and off-axis geometry of the trapping beam plus trapped spherical particle; 2. verified that the computed radiation trapping force for a freely propagating focused Gaussian laser beam incident on a spherical particle agrees with previous published calculations; 3. compared the small particle size and large particle size limits of the Mie calculation with the results of <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> theory and ray <span class="hlt">scattering</span> theory, respectively and verified that the comparison is correct for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> theory but found that ray theory omits an important light <span class="hlt">scattering</span> effect included in the Mie theory treatment; 4. generalized the calculation of the radiation trapping force on a spherical particle in the on-axis geometry from a freely propagating focused Gaussian laser beam to the realistic situation of a Gaussian beam truncated and focused by a high numerical aperture oil-immersion microscope objective lens and aberrated by the interface between the microscope cover slip and the liquid-filled sample volume; and 5. compared the calculated radiation trapping force for this geometry with the results of previously published experiments and found that the agreement is better than when using previously developed theories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7107E..12K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7107E..12K"><span id="translatedtitle">Analyses of <span class="hlt">scattering</span> characteristics of chosen anthropogenic aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaszczuk, Miroslawa; Mierczyk, Zygmunt; Muzal, Michal</p> <p>2008-10-01</p> <p>In the work, analyses of <span class="hlt">scattering</span> profile of chosen anthropogenic aerosols for two wavelengths (λ1 = 1064 nm and λ2 = 532 nm) were made. As an example of anthropogenic aerosol three different pyrotechnic mixtures (DM11, M2, M16) were taken. Main parameters of smoke particles were firstly analyzed and well described, taking particle shape and size into special consideration. Shape of particles was analyzed on the basis of SEM pictures, and particle size was measured. Participation of particles in each fixed fraction characterized by range of sizes was analyzed and parameters of smoke particles of characteristic sizes and function describing aerosol size distribution (ASD) were determinated. Analyses of <span class="hlt">scattering</span> profiles were carried out on the basis of both model of <span class="hlt">scattering</span> on spherical and nonspherical particles. In the case of spherical particles <span class="hlt">Rayleigh</span>-Mie model was used and for nonspherical particles analyses firstly model of spheroids was used, and then <span class="hlt">Rayleigh</span>-Mie one. For each characteristic particle one calculated value of four parameters (effective <span class="hlt">scattering</span> cross section σSCA, effective backscattering cross section σBSCA, <span class="hlt">scattering</span> efficiency QSCA, backscattering efficiency QBSCA) and value of backscattering coefficient β for whole particles population. Obtained results were compared with the same parameters calculated for natural aerosol (cirrus cloud).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6634680','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6634680"><span id="translatedtitle">Waist location and <span class="hlt">Rayleigh</span> range for higher-order mode laser beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Luxon, J.T.; Parker, D.E.; Karkheck, J.</p> <p>1984-07-01</p> <p>Self has presented simple equations for Gaussian-mode laser beams for calculating focused waist location and beam waist magnification in terms of the <span class="hlt">Rayleigh</span> range. Since the <span class="hlt">Rayleigh</span> range is a purely geometrical quantity. Self's equations can also be applied to higher-order mode beams. A convenient form of the <span class="hlt">Rayleigh</span> range for Hermite-Gaussian modes is presented along with representative results for Co/sub 2/ laser industrial processing facilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RScI...87kD602Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RScI...87kD602Z"><span id="translatedtitle">The upgrade of the Thomson <span class="hlt">scattering</span> system for measurement on the C-2/C-2U devices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhai, K.; Schindler, T.; Kinley, J.; Deng, B.; Thompson, M. C.</p> <p>2016-11-01</p> <p>The C-2/C-2U Thomson <span class="hlt">scattering</span> system has been substantially upgraded during the latter phase of C-2/C-2U program. A <span class="hlt">Rayleigh</span> channel has been added to each of the three polychromators of the C-2/C-2U Thomson <span class="hlt">scattering</span> system. Onsite spectral calibration has been applied to avoid the issue of different channel responses at different spots on the photomultiplier tube surface. With the added <span class="hlt">Rayleigh</span> channel, the absolute intensity response of the system is calibrated with <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in argon gas from 0.1 to 4 Torr, where the <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> signal is comparable to the Thomson <span class="hlt">scattering</span> signal at electron densities from 1 × 1013 to 4 × 1014 cm-3. A new signal processing algorithm, using a maximum likelihood method and including detailed analysis of different noise contributions within the system, has been developed to obtain electron temperature and density profiles. The system setup, spectral and intensity calibration procedure and its outcome, data analysis, and the results of electron temperature/density profile measurements will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920016126','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920016126"><span id="translatedtitle">Modelling atmospheric <span class="hlt">scatterers</span> using spacecraft observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rages, Kathy A.</p> <p>1992-01-01</p> <p>Voyager images of Triton indicate considerable spatial variability in the concentration of at least two different <span class="hlt">scattering</span> components in the atmosphere. Data from high phase angle limb scans were fit to Mie <span class="hlt">scattering</span> models to derive mean particle sizes, number densities, and vertical extent for both types of <span class="hlt">scattering</span> material at ten different locations between 15 deg S and 70 deg S. These fits reveal a thin haze at latitudes equatorward of 25-30 deg S. The imaging data can be fit reasonably well by both conservatively <span class="hlt">scattering</span> and absorbing hazes with particle sizes near 0.18 micron and optical depths of order 0.001-0.01. <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> haze fits the imaging data somewhat less well, and can be totally ruled out by combining the imaging and UVS measurements. At high southern latitudes, Triton displays clouds below an altitude of approximately 8 km, as well as the haze at higher altitudes. The clouds have particle sizes which may range from 0.7-2.0 microns, or may be near 0.25 micron. The atmospheric optical depth poleward of 30 deg S must be generally greater than 0.1, but need not be more than 0.3. Horizontal inhomogeneities are quite noticeable, especially at longitudes east of (i.e., higher than) 180 deg.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23043554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23043554"><span id="translatedtitle">Resonant coupling of <span class="hlt">Rayleigh</span> waves through a narrow fluid channel causing extraordinary low acoustic transmission.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garcia-Chocano, Victor M; Nagaraj; Lòpez-Rios, Tomàs; Gumen, Lyudmila; Sànchez-Dehesa, Josè; Krokhin, Arkadii</p> <p>2012-10-01</p> <p>Coupling of <span class="hlt">Rayleigh</span> waves propagating along two metal surfaces separated by a narrow fluid channel is predicted and experimentally observed. Although the coupling through a fluid (water) is weak, a strong synchronization in propagation of <span class="hlt">Rayleigh</span> waves even for the metals with sufficiently high elastic contrast (brass and aluminum) is observed. Dispersion equation for two polarizations of the coupled <span class="hlt">Rayleigh</span> waves is derived and experimentally confirmed. Excitation of coupled <span class="hlt">Rayleigh</span> waves in a channel of finite length leads to anomalously low transmission of acoustic energy at discrete set of resonant frequencies. This effect may find useful applications in the design of acoustic metamaterial screens and reflectors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026753','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026753"><span id="translatedtitle">Utilization of high-frequency <span class="hlt">Rayleigh</span> waves in near-surface geophysics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xia, J.; Miller, R.D.; Park, C.B.; Ivanov, J.; Tian, G.; Chen, C.</p> <p>2004-01-01</p> <p>Shear-wave velocities can be derived from inverting the dispersive phase velocity of the surface. The multichannel analysis of surface waves (MASW) is one technique for inverting high-frequency <span class="hlt">Rayleigh</span> waves. The process includes acquisition of high-frequency broad-band <span class="hlt">Rayleigh</span> waves, efficient and accurate algorithms designed to extract <span class="hlt">Rayleigh</span>-wave dispersion curves from <span class="hlt">Rayleigh</span> waves, and stable and efficient inversion algorithms to obtain near-surface S-wave velocity profiles. MASW estimates S-wave velocity from multichannel vertical compoent data and consists of data acquisition, dispersion-curve picking, and inversion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23d2111S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23d2111S"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability with finite current relaxation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silveira, F. E. M.; Orlandi, H. I.</p> <p>2016-04-01</p> <p>In this work, we explore the influence of perturbative wavelengths, shorter than those usually considered, on the growth rate of the <span class="hlt">Rayleigh</span>-Taylor modes. Therefore, we adopt an extended form of Ohm's law which includes a finite relaxation time of the current density due to inertial effects of charged species in the plasma. The restoring force density that acts upon charged species close to the mode rational surface takes into account a new term which is usually neglected with respect to the motional electromotive force. We find that the width of the resistive layer can be interpreted in terms of the "height" of free fall in a constant gravitational field, in the Alfvén time interval. We also show that the charged species must fall "down" in the constant gravitational field in order that the static state of equilibrium of the system becomes unstable to the linear perturbation. Through the principle of conservation of energy, we find a general formula which gives the growth rate γ of the <span class="hlt">Rayleigh</span>-Taylor modes. When the new term becomes negligible with respect to the motional electromotive force, we recover the standard result of the <span class="hlt">Rayleigh</span>-Taylor instability, which establishes that γ scales with the plasma resistivity η as γ ˜ η 1 / 3 . However, in the opposite limiting situation, we find that γ does not depend any longer on the plasma resistivity and scales now with the electron number density n e as γ ˜ ne - 1 / 2 . Further developments of our theory may contribute to improve our understanding on the excitation mechanisms of resistive plasma instabilities by transient phenomena such as shock waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020060234','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020060234"><span id="translatedtitle">Ocean Raman <span class="hlt">Scattering</span> in Satellite Backscatter UV Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vasilkov, Alexander P.; Joiner, Joanna; Gleason, James; Bhartia, Pawan; Bhartia, P. K. (Technical Monitor)</p> <p>2002-01-01</p> <p>Ocean Raman <span class="hlt">scattering</span> significantly contributes to the filling-in of solar Fraunhofer lines measured by satellite backscatter ultraviolet (buy) instruments in the cloudless atmosphere over clear ocean waters. A model accounting for this effect in buy measurements is developed and compared with observations from the Global Ozone Monitoring Experiment (GONE). The model extends existing models for ocean Raman <span class="hlt">scattering</span> to the UV spectral range. Ocean Raman <span class="hlt">scattering</span> radiance is propagated through the atmosphere using a concept of the Lambert equivalent reflectively and an accurate radiative transfer model for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>. The model and observations can be used to evaluate laboratory measurements of pure water absorption in the UV. The good agreement between model and observations suggests that buy instruments may be useful for estimating chlorophyll content.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9186E..0VS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9186E..0VS"><span id="translatedtitle">Half a century of light <span class="hlt">scatter</span> metrology and counting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stover, John C.</p> <p>2014-09-01</p> <p>Back in the early days Bill Wolf once said something like: "The guy with the lowest <span class="hlt">scatter</span> measurement is closest to the right answer." He was often right then - but not anymore. Everything has changed. Today measurements are limited by <span class="hlt">Rayleigh</span> <span class="hlt">scatter</span> from the air - not the instrument. We have both written and physical standards and everybody spells BRDF the same way. In the time it takes to give this talk, over 100,000 silicon wafers will be inspected around the world using a few thousand scatterometers - average price about one million dollars each. The way the world illuminates everything from homes to football fields is changing with the advent of high brightness LED's and these lighting systems are designed using a combination of <span class="hlt">scatter</span> metrology and analysis techniques - many of which were started at The Optical Sciences Center. This paper reviews two major highlights in half a century of <span class="hlt">scatter</span> metrology progress.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991PhRvL..67.3259R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991PhRvL..67.3259R"><span id="translatedtitle">Large growth <span class="hlt">Rayleigh</span>-Taylor experiments using shaped laser pulses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Remington, B. A.; Haan, S. W.; Glendinning, S. G.; Kilkenny, J. D.; Munro, D. H.; Wallace, R. J.</p> <p>1991-12-01</p> <p>Larege growth <span class="hlt">Rayleigh</span>-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of planar fluorosilicone foils with 50-μm wavelength initial surface perturbations. Foils with large-amplitude initial perturbation quickly enter the nonlinear RT regime, and show little growth. Foils with very-small-amplitude initial perturbations grow exponentially for longer, and show much larger growth factors. From comparisons with two-dimensional computer simulations, we deduce that the observed growth is about 60% of that expected for classical RT growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6130126','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6130126"><span id="translatedtitle">Large growth <span class="hlt">Rayleigh</span>-Taylor experiments using shaped laser pulses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Remington, B.A.; Haan, S.W.; Glendinning, S.G.; Kilkenny, J.D.; Munro, D.H.; Wallace, R.J. )</p> <p>1991-12-02</p> <p>Larege growth <span class="hlt">Rayleigh</span>-Taylor (RT) experiments have been conducted by pulse-shaped radiative acceleration of planar fluorosilicone foils with 50-{mu}m wavelength initial surface perturbations. Foils with large-amplitude initial perturbation quickly enter the nonlinear RT regime, and show little growth. Foils with very-small-amplitude initial perturbations grow exponentially for longer, and show much larger growth factors. From comparisons with two-dimensional computer simulations, we deduce that the observed growth is about 60% of that expected for classical RT growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/900067','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/900067"><span id="translatedtitle">Bubble Counts for <span class="hlt">Rayleigh</span>-Taylor Instability Using Image Analysis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miller, P L; Gezahegne, A G; Cook, A W; Cabot, W H; Kamath, C</p> <p>2007-01-24</p> <p>We describe the use of image analysis to count bubbles in 3-D, large-scale, LES [1] and DNS [2] of the <span class="hlt">Rayleigh</span>-Taylor instability. We analyze these massive datasets by first converting the 3-D data to 2-D, then counting the bubbles in the 2-D data. Our plots for the bubble count indicate there are four distinct regimes in the process of the mixing of the two fluids. We also show that our results are relatively insensitive to the choice of parameters in our analysis algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1089642','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1089642"><span id="translatedtitle">Theoretical and Experimental Studies of Magneto-<span class="hlt">Rayleigh</span>-Taylor Instabilities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lau, Yue Ying; Gilgenbach, Ronald</p> <p>2013-07-07</p> <p>Magneto-<span class="hlt">Rayleigh</span>-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11736506','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11736506"><span id="translatedtitle">Energy budget in <span class="hlt">Rayleigh</span>-Bénard convection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kerr, R M</p> <p>2001-12-10</p> <p>It is shown using three series of <span class="hlt">Rayleigh</span> number simulations of varying aspect ratio AR and Prandtl number Pr that the normalized dissipation at the wall, while significantly greater than 1, approaches a constant dependent upon AR and Pr. It is also found that the peak velocity, not the mean square velocity, obeys the experimental scaling of Ra(0.5). The scaling of the mean square velocity is closer to Ra(0.46), which is shown to be consistent with experimental measurements and the numerical results for the scaling of Nu and the temperature if there are strong correlations between the velocity and temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6415957','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6415957"><span id="translatedtitle">Nonlinear evolution of the unmagnetized ion <span class="hlt">Rayleigh</span>--Taylor instability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hassam, A.B.; Huba, J.D. )</p> <p>1990-09-01</p> <p>The nonlinear evolution of the unmagnetized ion <span class="hlt">Rayleigh</span>--Taylor instability is investigated. A nonlinear state corresponding to localized clumps of high-density plasma is obtained analytically. The characteristic scale size of the clumps is given by {Delta}{similar to}{ital D}({ital gL}{sub {ital n}}){sup {minus}1/2}, where {ital g} is the gravitational acceleration, {ital L}{sub {ital n}} is the density gradient scale length, and {ital D} is a diffusion coefficient associated with the short-scale dissipation processes in the system. It is shown numerically that this nonlinear state may be both accessible and stable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AmJPh..75..499F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AmJPh..75..499F"><span id="translatedtitle">An experiment on the <span class="hlt">Rayleigh</span> instability of charged liquid drops</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fong, Chee Sheng; Black, Nathan D.; Kiefer, Peter A.; Shaw, Raymond A.</p> <p>2007-06-01</p> <p>We describe a simple experiment to observe the fission of an electrically charged liquid droplet. <span class="hlt">Rayleigh</span> charge instability occurs when the electrostatic repulsion of charges on the surface of a droplet overcomes the droplet surface tension and tears the droplet apart. The experiment requires a low-power laser, simple optics, a CCD camera, and a quadrupole trap, which can be constructed using widely available and relatively straightforward instructions. The experiment was performed primarily by undergraduates as part of their senior research projects and can be implemented readily in an advanced undergraduate physics laboratory course.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980JSV....69..345D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980JSV....69..345D"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Ritz vibration analysis of Mindlin plates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dawe, D. J.; Roufaeil, O. L.</p> <p>1980-04-01</p> <p>The <span class="hlt">Rayleigh</span>-Ritz method is applied to the prediction of the natural frequencies of flexural vibration of square plates having general boundary conditions. The analysis is based on the use of Mindlin plate theory so that the effects of shear deformation and rotary inertia are included. The spatial variations of the plate deflection and the two rotations over the plate middle surface are assumed to be series of products of appropriate Timoshenko beam functions. Results are presented for a number of types of plate and these demonstrate the manner of convergence of the method as the number of terms in the assumed series increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21274185','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21274185"><span id="translatedtitle">Nonlinear <span class="hlt">Rayleigh</span>-Taylor instabilities in fast Z pinches</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miles, Aaron R.</p> <p>2009-03-15</p> <p>A simplified analytic model is presented to describe the implosion of a plasma column by an azimuthal magnetic field of sufficient magnitude to drive a strong shock wave into the plasma. This model is employed together with buoyancy-drag-based models of nonlinear single-mode and turbulent multimode <span class="hlt">Rayleigh</span>-Taylor growth to investigate the mixing process in such fast Z pinches. These models give predictions that characterize limitations the instability can impose on the implosion in terms of maximum convergence ratios attainable for an axially coherent pinch. Both the implosion and instability models are validated with results from high-resolution numerical simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...823...70T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...823...70T"><span id="translatedtitle">Light <span class="hlt">Scattering</span> by Fractal Dust Aggregates. I. Angular Dependence of <span class="hlt">Scattering</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tazaki, Ryo; Tanaka, Hidekazu; Okuzumi, Satoshi; Kataoka, Akimasa; Nomura, Hideko</p> <p>2016-06-01</p> <p>In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates <span class="hlt">scatter</span> light. In this study, the light <span class="hlt">scattering</span> properties of porous dust aggregates were calculated using a rigorous method, the T-matrix method, and the results were then compared with those obtained using the <span class="hlt">Rayleigh</span>-Gans-Debye (RGD) theory and Mie theory with the effective medium approximation (EMT). The RGD theory is applicable to moderately large aggregates made of nearly transparent monomers. This study considered two types of porous dust aggregates—ballistic cluster-cluster agglomerates (BCCAs) and ballistic particle-cluster agglomerates. First, the angular dependence of the <span class="hlt">scattered</span> intensity was shown to reflect the hierarchical structure of dust aggregates; the large-scale structure of the aggregates is responsible for the intensity at small <span class="hlt">scattering</span> angles, and their small-scale structure determines the intensity at large <span class="hlt">scattering</span> angles. Second, it was determined that the EMT underestimates the backward <span class="hlt">scattering</span> intensity by multiple orders of magnitude, especially in BCCAs, because the EMT averages the structure within the size of the aggregates. It was concluded that the RGD theory is a very useful method for calculating the optical properties of BCCAs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...585A.114P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...585A.114P"><span id="translatedtitle">The GTC exoplanet transit spectroscopy survey. II. An overly large <span class="hlt">Rayleigh</span>-like feature for exoplanet TrES-3b</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parviainen, H.; Pallé, E.; Nortmann, L.; Nowak, G.; Iro, N.; Murgas, F.; Aigrain, S.</p> <p>2016-01-01</p> <p>Aims: We search for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and K and Na absorption signatures from the atmosphere of TrES-3b using ground-based transmission spectroscopy covering the wavelength range from 530 to 950 nm as observed with the OSIRIS instrument at the Gran Telescopio CANARIAS. Methods: Our analysis is based on a Bayesian approach where the light curves covering a set of given passbands are fitted jointly with PHOENIX-calculated stellar limb darkening profiles. The analysis is carried out assuming both white and red noise that is temporally correlated, with two approaches (Gaussian processes and divide-by-white) to account for the red noise. Results: An initial analysis reveals a transmission spectrum that shows a strong <span class="hlt">Rayleigh</span>-like increase in extinction towards the blue end of the spectrum, and enhanced extinction around the K I resonance doublet near 767 nm. However, the signal amplitudes are significantly larger than expected from theoretical considerations. A detailed analysis reveals that the K I-like feature is entirely due to variability in the telluric O2 absorption, but the <span class="hlt">Rayleigh</span>-like feature remains unexplained. The light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A114</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22167131','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22167131"><span id="translatedtitle">NONLINEAR EVOLUTION OF <span class="hlt">RAYLEIGH</span>-TAYLOR INSTABILITY IN A RADIATION-SUPPORTED ATMOSPHERE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jiang, Yan-Fei; Stone, James M.; Davis, Shane W.</p> <p>2013-02-15</p> <p>The nonlinear regime of <span class="hlt">Rayleigh</span>-Taylor instability (RTI) in a radiation supported atmosphere, consisting of two uniform fluids with different densities, is studied numerically. We perform simulations using our recently developed numerical algorithm for multi-dimensional radiation hydrodynamics based on a variable Eddington tensor (VET) as implemented in Athena, focusing on the regime where <span class="hlt">scattering</span> opacity greatly exceeds absorption opacity. We find that the radiation field can reduce the growth and mixing rate of RTI, but this reduction is only significant when radiation pressure significantly exceeds gas pressure. Small-scale structures are also suppressed in this case. In the nonlinear regime, dense fingers sink faster than rarefied bubbles can rise, leading to asymmetric structures about the interface. By comparing the calculations that use a VET versus the Eddington approximation, we demonstrate that anisotropy in the radiation field can affect the nonlinear development of RTI significantly. We also examine the disruption of a shell of cold gas being accelerated by strong radiation pressure, motivated by models of radiation driven outflows in ultraluminous infrared galaxies. We find that when the growth timescale of RTI is smaller than acceleration timescale, the amount of gas that would be pushed away by the radiation field is reduced due to RTI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.206.1634M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.206.1634M"><span id="translatedtitle">Higher-mode ambient-noise <span class="hlt">Rayleigh</span> waves in sedimentary basins</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Yiran; Clayton, Robert W.; Li, Dunzhu</p> <p>2016-09-01</p> <p>We show that higher modes are an important component of high-frequency <span class="hlt">Rayleigh</span> waves in the cross-correlations over sedimentary basins. The particle motions provide a good test for distinguishing and separating the fundamental from the first higher mode, with the fundamental mode having retrograde and the first higher mode having prograde motion in the 1-10 s period of interest. The basement depth controls the cut-off period of the first higher mode, which coincides with a rapid increase (over period) in the particle-motion ellipticity or H/V ratio of the fundamental mode. The strong higher mode we observed is not only due to the low-velocity sedimentary layer but also due to the noise sources with significant radial component such as the basin edge <span class="hlt">scattering</span>. It is important to correctly identify the mode order when inverting the dispersion curves because misidentifying the higher mode as fundamental will lead to an anomalous high VSV velocity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApJ...763..102J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...763..102J"><span id="translatedtitle">Nonlinear Evolution of <span class="hlt">Rayleigh</span>-Taylor Instability in a Radiation-supported Atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Yan-Fei; Davis, Shane W.; Stone, James M.</p> <p>2013-02-01</p> <p>The nonlinear regime of <span class="hlt">Rayleigh</span>-Taylor instability (RTI) in a radiation supported atmosphere, consisting of two uniform fluids with different densities, is studied numerically. We perform simulations using our recently developed numerical algorithm for multi-dimensional radiation hydrodynamics based on a variable Eddington tensor (VET) as implemented in Athena, focusing on the regime where <span class="hlt">scattering</span> opacity greatly exceeds absorption opacity. We find that the radiation field can reduce the growth and mixing rate of RTI, but this reduction is only significant when radiation pressure significantly exceeds gas pressure. Small-scale structures are also suppressed in this case. In the nonlinear regime, dense fingers sink faster than rarefied bubbles can rise, leading to asymmetric structures about the interface. By comparing the calculations that use a VET versus the Eddington approximation, we demonstrate that anisotropy in the radiation field can affect the nonlinear development of RTI significantly. We also examine the disruption of a shell of cold gas being accelerated by strong radiation pressure, motivated by models of radiation driven outflows in ultraluminous infrared galaxies. We find that when the growth timescale of RTI is smaller than acceleration timescale, the amount of gas that would be pushed away by the radiation field is reduced due to RTI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..GECFT1071W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..GECFT1071W"><span id="translatedtitle">Laser Thomson <span class="hlt">Scattering</span> Diagnostics in the Low-Temperature Plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woo, Hyun-Jong; Chung, Kyu-Sun</p> <p>2008-10-01</p> <p>Laser Thomson <span class="hlt">Scattering</span> (LTS) is the non-invasive method for measuring the electron temperature and its density, which can be used for the calibrations of electric probes within collisional and magnetized plasmas. For LTS diagnostics in the low-temperature plasmas, one need to special optics for detection of the <span class="hlt">scattered</span> light with restricting the <span class="hlt">Rayleigh</span> and Stray lights. For this, one uses the Triple Grating Spectrometer (TGS), which is composed of <span class="hlt">Rayleigh</span> block (notch filter for <span class="hlt">Rayleigh</span> light) and double grating filter (DGF). All focusing lenses are used with achromatic doublet configuration for reducing the non-linear optical effects such as spherical aberration, coma, etc. The specifications of the grating and achromatic doublet lens are 1800 gr/mm with the dimensions of 84 mm x 84 mm and 400 mm of focal length with the diameter of 100 mm, respectively. In this configurations, the linear dispersion is given as 1.006 nm/mm. Considering the dimension of Charged Coupled Device (CCD) with the linear dispersion, the LTS system can be measure the electron temperatures of less than 10 eV (in most laboratory plasmas). The initial measurement of LTS measurement and comparative study with single probe are done in Divertor Plasma Simulator (DiPS) with the following plasma parameters; plasma density of 10^11-10^13 cm-3, electron temperature of 1-4 eV, and the magnetic field of 0.2-1 kG, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992PhFlB...4..967R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992PhFlB...4..967R"><span id="translatedtitle">Large growth, planar <span class="hlt">Rayleigh</span>-Taylor experiments on Nova</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Remington, B. A.; Haan, S. W.; Glendinning, S. G.; Kilkenny, J. D.; Munro, D. H.; Wallace, R. J.</p> <p>1992-04-01</p> <p>A set of indirect-drive experiments to study large growth <span class="hlt">Rayleigh</span>-Taylor instability using shaped laser pulses at the Nova laser facility has been conducted. Planar foils of fluorosilicone were accelerated by x-ray ablation. The foil trajectory was measured using edge-on radiography. In separate experiments using face-on radiography, contrast in optical depth was measured as a function of time, from which the evolution of 50 μm wavelength initially sinusoidal surface perturbations was deduced. Holding other parameters fixed, the amplitude of the initial perturbation was varied by up to a factor of 30 in separate shots. The foils with the smallest initial perturbation exhibited growth factors of 75 in contrast. Foils with large initial amplitude perturbation gave growth factors of 6 or less, and displayed the ``bubble-and-spike'' shape characteristic of the nonlinear <span class="hlt">Rayleigh</span>-Taylor instability. Comparisons of two-dimensional computer simulations with both the measured foil trajectory and the perturbation growth show good agreement, provided that a suitable opacity model is chosen. In the linear regime the observed growth rates are 60%-75% of classical, the reduction attributed primarily to ablative stabilization. The observed onset of harmonic generation, signaling the transition into the nonlinear regime, is well predicted by third-order theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7233924','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7233924"><span id="translatedtitle">Large growth, planar <span class="hlt">Rayleigh</span>--Taylor experiments on Nova</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Remington, B.A.; Haan, S.W.; Glendinning, S.G.; Kilkenny, J.D.; Munro, D.H.; Wallace, R.J. )</p> <p>1992-04-01</p> <p>A set of indirect-drive experiments to study large growth <span class="hlt">Rayleigh</span>--Taylor instability using shaped laser pulses at the Nova laser facility has been conducted. Planar foils of fluorosilicone were accelerated by x-ray ablation. The foil trajectory was measured using edge-on radiography. In separate experiments using face-on radiography, contrast in optical depth was measured as a function of time, from which the evolution of 50 {mu}m wavelength initially sinusoidal surface perturbations was deduced. Holding other parameters fixed, the amplitude of the initial perturbation was varied by up to a factor of 30 in separate shots. The foils with the smallest initial perturbation exhibited growth factors of 75 in contrast. Foils with large initial amplitude perturbation gave growth factors of 6 or less, and displayed the bubble-and-spike'' shape characteristic of the nonlinear <span class="hlt">Rayleigh</span>--Taylor instability. Comparisons of two-dimensional computer simulations with both the measured foil trajectory and the perturbation growth show good agreement, provided that a suitable opacity model is chosen. In the linear regime the observed growth rates are 60%--75% of classical, the reduction attributed primarily to ablative stabilization. The observed onset of harmonic generation, signaling the transition into the nonlinear regime, is well predicted by third-order theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JFM...784..565S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JFM...784..565S"><span id="translatedtitle">Optimal heat transport solutions for <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sondak, David; Smith, Leslie M.; Waleffe, Fabian</p> <p>2015-12-01</p> <p>Steady flows that optimize heat transport are obtained for two-dimensional <span class="hlt">Rayleigh</span>-B\\'enard convection with no-slip horizontal walls for a variety of Prandtl numbers $Pr$ and <span class="hlt">Rayleigh</span> number up to $Ra\\sim 10^9$. Power law scalings of $Nu\\sim Ra^{\\gamma}$ are observed with $\\gamma\\approx 0.31$, where the Nusselt number $Nu$ is a non-dimensional measure of the vertical heat transport. Any dependence of the scaling exponent on $Pr$ is found to be extremely weak. On the other hand, the presence of two local maxima of $Nu$ with different horizontal wavenumbers at the same $Ra$ leads to the emergence of two different flow structures as candidates for optimizing the heat transport. For $Pr \\lesssim 7$, optimal transport is achieved at the smaller maximal wavenumber. In these fluids, the optimal structure is a plume of warm rising fluid which spawns left/right horizontal arms near the top of the channel, leading to downdrafts adjacent to the central updraft. For $Pr > 7$ at high-enough Ra, the optimal structure is a single updraft absent significant horizontal structure, and characterized by the larger maximal wavenumber.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AcMSn..24..143F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AcMSn..24..143F"><span id="translatedtitle">Non-linear characteristics of <span class="hlt">Rayleigh</span>-Taylor instable perturbations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fan, Zhengfeng; Luo, Jisheng</p> <p>2008-04-01</p> <p>The direct numerical simulation method is adopted to study the non-linear characteristics of <span class="hlt">Rayleigh</span>-Taylor instable perturbations at the ablation front of a 200 μm planar CH ablation target. In the simulation, the classical electrical thermal conductivity is included, and NND difference scheme is used. The linear growth rates obtained from the simulation agree with the Takabe formula. The amplitude distribution of the density perturbation at the ablation front is obtained for the linear growth case. The non-linear characteristics of <span class="hlt">Rayleigh</span>-Taylor instable perturbations are analyzed and the numerical results show that the amplitude distributions of the compulsive harmonics are very different from that of the fundamental perturbation. The characteristics of the amplitude distributions of the harmonics and their fast growth explain why spikes occur at the ablation front. The numerical results also show that non-linear effects have relations with the phase differences of double mode initial perturbations, and different phase differences lead to varied spikes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9795E..17F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9795E..17F"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-backscattering doppler broadening correction for differential absorption lidar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fan, Lanlan; Zhang, Yinchao; Chen, Siying; Guo, Pan; Chen, He</p> <p>2015-11-01</p> <p>The spectral broadening by <span class="hlt">Rayleigh</span> backscattering can cause large changes in water vapor echo signals, causing errors when the water vapor concentration is inversed by differential absorption lidar (DIAL). A correction algorithm is proposed to revise the errors due to the effect of laser spectral broadening. The relative errors of water vapor are calculated in cases of different aerosol distribution and temperature changes before and after correction. The results show that measurement errors due to the Doppler broadening are more than 5% before correction and a 2% measurement error after corrected for the case of a smooth, background aerosol distribution. However, due to the high aerosol gradients and strong temperature inversion, errors can be up to 40% and 10% with no corrections for this effect, respectively. The relative errors can reduce to less than 2% after correction. Hence, the correction algorithm for <span class="hlt">Rayleigh</span> Doppler broadening can improve detection accuracy in H2O DIAL measurements especially when it is applied to high aerosol concentration or strong temperature inversion.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27176406','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27176406"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability of viscous fluids with phase change.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Byoung Jae; Kim, Kyung Doo</p> <p>2016-04-01</p> <p>Film boiling on a horizontal surface is a typical example of the <span class="hlt">Rayleigh</span>-Taylor instability. During the film boiling, phase changes take place at the interface, and thus heat and mass transfer must be taken into consideration in the stability analysis. Moreover, since the vapor layer is not quite thick, a viscous flow must be analyzed. Existing studies assumed equal kinematic viscosities of two fluids, and/or considered thin viscous fluids. The purpose of this study is to derive the analytical dispersion relation of the <span class="hlt">Rayleigh</span>-Taylor instability for more general conditions. The two fluids have different properties. The thickness of the vapor layer is finite, but the liquid layer is thick enough to be nearly semi-infinite in view of perturbation. Initially, the vapor is in equilibrium with the liquid at the interface, and the direction of heat transfer is from the vapor side to the liquid side. In this case, the phase change has a stabilizing effect on the growth rate of the interface. When the vapor layer is thin, there is a coupled effect of the vapor viscosity, phase change, and vapor thickness on the critical wave number. For the other limit of a thick vapor, both the liquid and vapor viscosities influence the critical wave number. Finally, the most unstable wavelength is investigated. When the vapor layer is thin, the most unstable wavelength is not affected by phase change. When the vapor layer is thick, however, it increases with the increasing rate of phase change. PMID:27176406</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4486928','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4486928"><span id="translatedtitle">The Inhibition of the <span class="hlt">Rayleigh</span>-Taylor Instability by Rotation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Baldwin, Kyle A.; Scase, Matthew M.; Hill, Richard J. A.</p> <p>2015-01-01</p> <p>It is well-established that the Coriolis force that acts on fluid in a rotating system can act to stabilise otherwise unstable flows. Chandrasekhar considered theoretically the effect of the Coriolis force on the <span class="hlt">Rayleigh</span>-Taylor instability, which occurs at the interface between a dense fluid lying on top of a lighter fluid under gravity, concluding that rotation alone could not stabilise this system indefinitely. Recent numerical work suggests that rotation may, nevertheless, slow the growth of the instability. Experimental verification of these results using standard techniques is problematic, owing to the practical difficulty in establishing the initial conditions. Here, we present a new experimental technique for studying the <span class="hlt">Rayleigh</span>-Taylor instability under rotation that side-steps the problems encountered with standard techniques by using a strong magnetic field to destabilize an otherwise stable system. We find that rotation about an axis normal to the interface acts to retard the growth rate of the instability and stabilise long wavelength modes; the scale of the observed structures decreases with increasing rotation rate, asymptoting to a minimum wavelength controlled by viscosity. We present a critical rotation rate, dependent on Atwood number and the aspect ratio of the system, for stabilising the most unstable mode. PMID:26130005</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26130005','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26130005"><span id="translatedtitle">The Inhibition of the <span class="hlt">Rayleigh</span>-Taylor Instability by Rotation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baldwin, Kyle A; Scase, Matthew M; Hill, Richard J A</p> <p>2015-01-01</p> <p>It is well-established that the Coriolis force that acts on fluid in a rotating system can act to stabilise otherwise unstable flows. Chandrasekhar considered theoretically the effect of the Coriolis force on the <span class="hlt">Rayleigh</span>-Taylor instability, which occurs at the interface between a dense fluid lying on top of a lighter fluid under gravity, concluding that rotation alone could not stabilise this system indefinitely. Recent numerical work suggests that rotation may, nevertheless, slow the growth of the instability. Experimental verification of these results using standard techniques is problematic, owing to the practical difficulty in establishing the initial conditions. Here, we present a new experimental technique for studying the <span class="hlt">Rayleigh</span>-Taylor instability under rotation that side-steps the problems encountered with standard techniques by using a strong magnetic field to destabilize an otherwise stable system. We find that rotation about an axis normal to the interface acts to retard the growth rate of the instability and stabilise long wavelength modes; the scale of the observed structures decreases with increasing rotation rate, asymptoting to a minimum wavelength controlled by viscosity. We present a critical rotation rate, dependent on Atwood number and the aspect ratio of the system, for stabilising the most unstable mode. PMID:26130005</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..DFD.MP001T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..DFD.MP001T"><span id="translatedtitle">Experimental Study of <span class="hlt">Rayleigh</span>-Taylor Instability Using Paramagnetic Fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsiklashvili, Vladimer; Likhachev, Oleg; Jacobs, Jeffry</p> <p>2009-11-01</p> <p>Experiments that take advantage of the properties of paramagnetic liquids are used to study <span class="hlt">Rayleigh</span>-Taylor instability. A gravitationally unstable combination of a paramagnetic salt solution and a nonmagnetic solution is initially stabilized by a magnetic field gradient that is produced by the contoured pole-caps of a large electromagnet. <span class="hlt">Rayleigh</span>-Taylor instability originates with the rapid removal of current from the electromagnet, which results in the heavy liquid falling into the light liquid due to gravity and, thus, mixing with it. The mixing zone is visualized by back-lit photography and is recorded with a digital video camera. For visualization purposes, a blue-green dye is added to the magnetic fluid. The mixing rate of the two liquids is determined from an averaged dye concentration across the mixing layer by means of the Beer-Lambert law. After removal of the suspending magnetic field, the initially flat interface between the two liquids develops a random surface pattern with the dominant length scale well approximated by the fastest growing wavelength in accordance with the viscous linear stability theory. Several combinations of paramagnetic and nonmagnetic solutions have been considered during the course of the research. A functional dependence of the mixing layer growth constant, α, on the properties of the liquids is a primary subject of the present study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/960921','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/960921"><span id="translatedtitle">Heat transport measurements in turbulent rotating <span class="hlt">Rayleigh</span>-Benard convection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ecke, Robert E; Liu, Yuanming</p> <p>2008-01-01</p> <p>We present experimental heat transport measurements of turbulent <span class="hlt">Rayleigh</span>-Benard convection with rotation about a vertical axis. The fluid, water with Prandtl number ({sigma}) about 6, was confined in a cell which had a square cross section of 7.3 cm x 7.3 cm and a height of 9.4 cm. Heat transport was measured for <span class="hlt">Rayleigh</span> numbers 2 x 10{sup 5} < Ra < 5 x 10{sup 8} and Taylor numbers 0 < Ta < 5 x 10{sup 9}. We show the variation of normalized heat transport, the Nusselt number, at fixed dimensional rotation rate {Omega}{sub D}, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed Rossby number Ro. The scaling of heat transport in the range 10{sup 7} to about 10{sup 9} is roughly 0.29 with a Ro dependent coefficient or equivalently is also well fit by a combination of power laws of the form a Ra{sup 1/5} + b Ra{sup 1/3} . The range of Ra is not sufficient to differentiate single power law or combined power law scaling. The overall impact of rotation on heat transport in turbulent convection is assessed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAG...134..267L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAG...134..267L"><span id="translatedtitle"><span class="hlt">Rayleigh</span> wave inversion using heat-bath simulated annealing algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Yongxu; Peng, Suping; Du, Wenfeng; Zhang, Xiaoyang; Ma, Zhenyuan; Lin, Peng</p> <p>2016-11-01</p> <p>The dispersion of <span class="hlt">Rayleigh</span> waves can be used to obtain near-surface shear (S)-wave velocity profiles. This is performed mainly by inversion of the phase velocity dispersion curves, which has been proven to be a highly nonlinear and multimodal problem, and it is unsuitable to use local search methods (LSMs) as the inversion algorithm. In this study, a new strategy is proposed based on a variant of simulated annealing (SA) algorithm. SA, which simulates the annealing procedure of crystalline solids in nature, is one of the global search methods (GSMs). There are many variants of SA, most of which contain two steps: the perturbation of model and the Metropolis-criterion-based acceptance of the new model. In this paper we propose a one-step SA variant known as heat-bath SA. To test the performance of the heat-bath SA, two models are created. Both noise-free and noisy synthetic data are generated. Levenberg-Marquardt (LM) algorithm and a variant of SA, known as the fast simulated annealing (FSA) algorithm, are also adopted for comparison. The inverted results of the synthetic data show that the heat-bath SA algorithm is a reasonable choice for <span class="hlt">Rayleigh</span> wave dispersion curve inversion. Finally, a real-world inversion example from a coal mine in northwestern China is shown, which proves that the scheme we propose is applicable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvE..93d3123K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvE..93d3123K&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Taylor instability of viscous fluids with phase change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Byoung Jae; Kim, Kyung Doo</p> <p>2016-04-01</p> <p>Film boiling on a horizontal surface is a typical example of the <span class="hlt">Rayleigh</span>-Taylor instability. During the film boiling, phase changes take place at the interface, and thus heat and mass transfer must be taken into consideration in the stability analysis. Moreover, since the vapor layer is not quite thick, a viscous flow must be analyzed. Existing studies assumed equal kinematic viscosities of two fluids, and/or considered thin viscous fluids. The purpose of this study is to derive the analytical dispersion relation of the <span class="hlt">Rayleigh</span>-Taylor instability for more general conditions. The two fluids have different properties. The thickness of the vapor layer is finite, but the liquid layer is thick enough to be nearly semi-infinite in view of perturbation. Initially, the vapor is in equilibrium with the liquid at the interface, and the direction of heat transfer is from the vapor side to the liquid side. In this case, the phase change has a stabilizing effect on the growth rate of the interface. When the vapor layer is thin, there is a coupled effect of the vapor viscosity, phase change, and vapor thickness on the critical wave number. For the other limit of a thick vapor, both the liquid and vapor viscosities influence the critical wave number. Finally, the most unstable wavelength is investigated. When the vapor layer is thin, the most unstable wavelength is not affected by phase change. When the vapor layer is thick, however, it increases with the increasing rate of phase change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940004262&hterms=PVDF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DPVDF','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940004262&hterms=PVDF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DPVDF"><span id="translatedtitle">Experimental and theoretical study of <span class="hlt">Rayleigh</span>-Lamb wave propagation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rogers, Wayne P.; Datta, Subhendu K.; Ju, T. H.</p> <p>1990-01-01</p> <p>Many space structures, such as the Space Station Freedom, contain critical thin-walled components. The structural integrity of thin-walled plates and shells can be monitored effectively using acoustic emission and ultrasonic testing in the <span class="hlt">Rayleigh</span>-Lamb wave frequency range. A new PVDF piezoelectric sensor has been developed that is well suited to remote, inservice nondestructive evaluation of space structures. In the present study the new sensor was used to investigate <span class="hlt">Rayleigh</span>-Lamb wave propagation in a plate. The experimental apparatus consisted of a glass plate (2.3 m x 25.4 mm x 5.6 mm) with PVDF sensor (3 mm diam.) mounted at various positions along its length. A steel ball impact served as a simulated acoustic emission source, producing surface waves, shear waves and longitudinal waves with dominant frequencies between 1 kHz and 200 kHz. The experimental time domain wave-forms were compared with theoretical predictions of the wave propagation in the plate. The model uses an analytical solution for the Green's function and the measured response at a single position to predict response at any other position in the plate. Close agreement was found between the experimental and theoretical results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998APS..DFD..JI05F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998APS..DFD..JI05F"><span id="translatedtitle">Effects of Rotation on a Large <span class="hlt">Rayleigh</span> Number Bridgman Furnace</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foster, M. R.</p> <p>1998-11-01</p> <p>It is known that rotating a Bridgman furnace in a centrifuge improves the crystal quality at large <span class="hlt">Rayleigh</span> number(W.Weber, G. Neumann & G. Mddot u)ller, J. Crys. Growth 100, 145 (1990). Here we determine improvements achieved by rotating the ampoule about its vertical axis. We know that, in the absence of rotation, if the <span class="hlt">Rayleigh</span> number, Ra, is large and Biot number is small, much larger solutal variations in the crystal are produced by azimuthal variations in the side-wall heating than from the axisymmetric component. However, at moderately large Taylor numbers, the first effects are to reduce the helical variation in solute concentration by inhibiting vertical motion in the melt, and so for Taylor numbers larger than O(Ra^1/6), the melt convection due to axisymmetric heating produces the larger solutal variation than that from azimuthal variations. As the Taylor number increases, the helical component of material segregation continues to decline in magnitude. However, in spite of changes in the interfacial boundary layer for Taylor numbers of order Ra^1/3 and larger, the outer flow/boundary layer coupling is unaltered for axisymmetry. It is not until the Taylor number is O(Ra^1/2) that the axisymmetric flow undergoes a change sufficiently dramatic to allow significant reduction in the material segregation from the zero-rotation case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1087663','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1087663"><span id="translatedtitle">Plasmon Mapping in Metallic Nanostructures and its Application to Single Molecule Surface Enhanced Raman <span class="hlt">Scattering</span>: Imaging Electromagnetic Hot-Spots and Analyte Location</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Camden, Jon P</p> <p>2013-07-16</p> <p>A major component of this proposal is to elucidate the connection between optical and electron excitation of plasmon modes in metallic nanostructures. These accomplishments are reported: developed a routine protocol for obtaining spatially resolved, low energy EELS spectra, and resonance <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> spectra from the same nanostructures.; correlated optical <span class="hlt">scattering</span> spectra and plasmon maps obtained using STEM/EELS.; and imaged electromagnetic hot spots responsible for single-molecule surface-enhanced Raman <span class="hlt">scattering</span> (SMSERS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T33A2612L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T33A2612L"><span id="translatedtitle">Subduction zones beneath Indonesia imaged by <span class="hlt">Rayleigh</span> wave phase velocity tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, F.; Yang, T.; Harmon, N.</p> <p>2013-12-01</p> <p>Situated at the junction of several tectonic plates including Indian-Australia, Eurasia, and Philippine Sea, the Indonesian archipelago is one of the most tectonically complex regions on earth with subductions, collisions and accretions occurring along and within its boundaries. A high-resolution lithospheric and upper mantle model, therefore, is needed to understand these complex processes beneath this region. We present a phase velocity model derived from teleseismic <span class="hlt">Rayleigh</span> waves recorded at seismic stations in this region. We use the modified version of the two-plane wave tomography, in which the non-planar effects of surface wave propagation such as multipathing and <span class="hlt">scattering</span> are accounted for by two plane wave interference and using of finite frequency kernels. We measure the amplitudes and phases at 16 individual periods ranging from 20s to 150s for the fundamental mode of <span class="hlt">Rayleigh</span> waves at over 30 stations. 254 earthquakes are selected from global events greater than Ms 5.5 in the distance range of 25°- 150°. To account for the wavefield inconsistencies among stations for each earthquake due to the large scale of our study region, we divide the seismic array into 4 groups of stations in the two-plane wave parameter inversion. The phase velocity maps from our preliminary results show coherent features between adjacent periods. The most dominant structure in phase velocity maps for all periods is the strong fast-velocity belts beneath Sunda Trench, Java Trench, Timor Trough and the trenches around Celebes Sea, which shift gradually toward the subduction directions. The strength of the high velocity anomaly varies among trenches, likely suggesting the different age of subducting slabs. In addition, a velocity contrast in the middle of Borneo appears to mark the Lupar Line, a boundary between the stable Sundaland continental core and fragments of ophiolitic and Asian continental material accreted to Borneo during the Cretaceous. The 3-D shear wave structure</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JQSRT.183..154S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JQSRT.183..154S"><span id="translatedtitle">Radiance and polarization in the diffusion region with an arbitrary <span class="hlt">scattering</span> phase matrix</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Bingqiang; Kattawar, George W.; Yang, Ping</p> <p>2016-11-01</p> <p>Radiance and polarization patterns in an optically deep region, the so-called diffusion region or asymptotic region, of a homogeneous atmosphere or ocean, depend mainly on the <span class="hlt">scattering</span> phase matrix and the single-<span class="hlt">scattering</span> albedo of the medium. The radiance and polarization properties in the diffusion region for an arbitrary <span class="hlt">scattering</span> phase matrix can be obtained in terms of a series of the generalized spherical functions. The number of terms is closely related to the single-<span class="hlt">scattering</span> albedo of the medium. If the medium is conservative, the radiance is isotropic in conjunction with no polarization. If the single-<span class="hlt">scattering</span> albedo is close to 1, several terms are sufficient to obtain the patterns, in which the degree of polarization feature is less than 1%. If the medium is highly absorptive, more expansion terms are required to obtain the diffusion patterns. The examples of simulated radiance and polarization patterns for <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, Henyey-Greenstein-<span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, and haze L and cloud C1 <span class="hlt">scattering</span>, defined by Deirmendjian, are calculated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22820101O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22820101O"><span id="translatedtitle">Raman <span class="hlt">scattering</span> by H2 and N2 in the atmospheres of exoplanets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oklopcic, Antonija; Hirata, Christopher M.; Heng, Kevin</p> <p>2016-06-01</p> <p><span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> is an important source of opacity in the atmospheres of exoplanets at short optical and near-UV wavelengths. Raman <span class="hlt">scattering</span> is an inelastic process related to <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, but with a weaker cross section. We analyze the signatures of Raman <span class="hlt">scattering</span> imprinted in the reflected light and the geometric albedo of exoplanets. Raman <span class="hlt">scattering</span> causes filling-in of absorption lines in the incident spectrum, thus producing sharp enhancements in the geometric albedo. It also shifts the wavelengths of spectral features in the reflected light causing the Raman ghost lines. Observing the albedo enhancements could be used to measure the column density of the <span class="hlt">scattering</span> molecule and provide constrains on the presence of clouds and hazes in the atmosphere. Observing the Raman ghost lines could be used to spectroscopically identify the main <span class="hlt">scatterer</span> in the atmosphere -- molecules like H2 or N2 which do not show prominent spectral signatures in the optical wavelength range. If detected, ghost lines could also provide information about the temperature of the atmosphere. Here we present how these signatures of Raman <span class="hlt">scattering</span> in hydrogen- and nitrogen-dominated atmospheres can be used as probes of atmospheric pressure, temperature and composition. We analyze the feasibility of detecting these features in the albedo spectra of nearby exoplanets with the existing and future observational facilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFD.G2010V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFD.G2010V"><span id="translatedtitle">Torsional oscillation of the large-scale circulation in turbulent <span class="hlt">Rayleigh</span>-Bénard convection at large <span class="hlt">Rayleigh</span> numbers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Gils, Dennis P. M.; He, Xiaozhou; Ahlers, Guenter; Bodenschatz, Eberhard</p> <p>2013-11-01</p> <p>We present temperature measurements in turbulent <span class="hlt">Rayleigh</span>--Bénard convection (RBC) over the <span class="hlt">Rayleigh</span> number range 3 . 0 ×1013 <= Ra <= 1 . 3 ×1014 and at constant Prandtl number ⪻ ~ 0 . 8 . The RBC sample, known as the High-Pressure Convection Facility (HPCF) of Göttingen, is an upright cylinder of aspect ratio Γ = 1 . 00 . Using three horizontal rows of thermistors at different heights in the sample, we determined the orientation angle of the large-scale circulation (LSC) plane, similar to. Results identify a well established single-roll LSC with a periodic ``torsional'' mode with a frequency fC . The values of fC are consistent with the frequencies fL obtained from power spectra P (f) of temperature time series taken at mid-height of the sample. The non-dimensionalized frequencies f~C are well described by a power law: f~C ~Raζf with ζf = 0 . 427 +/- 0 . 001 . Supported by the Max Planck Society, the Volkswagen Stiftung, the DFD Sonderforschungsbereich SFB963, and NSF grant DMR11-58514.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJT....37..101G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJT....37..101G"><span id="translatedtitle">Laser-Generated <span class="hlt">Rayleigh</span> Waves Propagating in Transparent Viscoelastic Adhesive Coating/Metal Substrate Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guan, Yi-jun; Sun, Hong-xiang; Yuan, Shou-qi; Zhang, Shu-yi; Ge, Yong</p> <p>2016-10-01</p> <p>We have established numerical models for simulating laser-generated <span class="hlt">Rayleigh</span> waves in coating/substrate systems by a finite element method and investigated the propagation characteristics of <span class="hlt">Rayleigh</span> waves in systems concerning the viscoelasticity and transparency of adhesive coatings. In this way, we have studied the influence of the mechanical properties of the coating, such as the elastic moduli, viscoelastic moduli, coating thickness, transparency, and coating material, on the propagation characteristics of the <span class="hlt">Rayleigh</span> waves. The results show that the propagation characteristics of the <span class="hlt">Rayleigh</span> waves can be divided into low- and high-frequency parts. The high-frequency propagation characteristics of the <span class="hlt">Rayleigh</span> wave are closely related to the properties of the adhesive coating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/963743','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/963743"><span id="translatedtitle">Approach for Selection of <span class="hlt">Rayleigh</span> Damping Parameters Used for Time History Analysis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>R. E. Spears; S. R. Jensen</p> <p>2009-07-01</p> <p>Nonlinearities, whether geometric or material, need to be addressed in seismic analysis. One good analysis method that can address these nonlinearities is direct time integration with <span class="hlt">Rayleigh</span> damping. Modal damping is the damping typically specified in seismic analysis Codes and Standards. Modal damping is constant for all frequencies where <span class="hlt">Rayleigh</span> damping varies with frequency. An approach is proposed here for selection of <span class="hlt">Rayleigh</span> damping coefficients to be used in seismic analyses that are consistent with given Modal damping. The approach uses the difference between the modal damping response and the <span class="hlt">Rayleigh</span> damping response along with effective mass properties of the model being evaluated to match overall system response levels. This paper provides a simple example problem to demonstrate the approach. It also provides results for a finite element model representing an existing piping system. Displacement, acceleration, and stress results are compared from model runs using modal damping and model runs using <span class="hlt">Rayleigh</span> damping with coefficients selected using the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PMM...105..263P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PMM...105..263P"><span id="translatedtitle">On the <span class="hlt">Rayleigh</span> law of magnetization. Symmetrical and asymmetric hysteresis loops. Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ponomarev, Yu. F.</p> <p>2008-03-01</p> <p>Results of an experimental study of symmetrical and asymmetric loops of magnetic hysteresis in weak ac fields are given (<span class="hlt">Rayleigh</span> region). The asymmetric loops are observed when a dc magnetizing field is additionally applied to the ferromagnetic material together with a weak ac field. The studies have been carried out on a manganese-zinc ferrite of grade M1000NM-A. It has been shown that the symmetrical hysteresis loops obey the mathematical <span class="hlt">Rayleigh</span> model by no means strictly. It has been revealed that if the dc magnetizing field is in the <span class="hlt">Rayleigh</span> region, then the hysteresis loops in the ac field remain symmetrical as before. But if the dc field falls outside the <span class="hlt">Rayleigh</span> region, then the hysteresis loops become asymmetric. This asymmetry is caused by the different values of the remanences on the ascending and descending branches of the hysteresis loop with the same quadratic dependence of magnetization on the field as in the <span class="hlt">Rayleigh</span> case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002ASAJ..111Q2463S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002ASAJ..111Q2463S&link_type=ABSTRACT"><span id="translatedtitle">Statistical modeling of <span class="hlt">scattering</span> from biological media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shankar, P. M.</p> <p>2002-05-01</p> <p>The statistics of the backscattered ultrasonic echo from tissue can provide information on its characteristics. Such information is useful in the classification of tissues in biomedicine. For example, some of the tissue properties may point to malignancies in certain lesions in liver, breast, or kidneys. The models employed in describing the backscattered echo are therefore very crucial to the success of these classification methods. These models must take into account the number density of <span class="hlt">scatterers</span>, cross sections of <span class="hlt">scatterers</span>, variation in cross sections of the <span class="hlt">scatterers</span>, and any alignment (periodic, quasiperiodic, and purely random) of the <span class="hlt">scatterers</span>. Parameters reflecting these features can be extracted from the backscattered echo using these models. They can be directly related to the properties of the tissue such as the presence of an abnormal growth, and further classification of the growth as benign and malignant. They may also be used to form parametric images to assist the clinicians in making a medical diagnosis. A number of models ranging from <span class="hlt">Rayleigh</span>, Poisson, K-, Weibull, and Nakagami will be discussed along with the relevance of their parameters and utility of the parameters in biomedicine. Specific applications to classification of breast lesions in ultrasonic B-scans will be described. [Work supported by NIH-NCI No. 52823.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMIN44A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMIN44A..08G"><span id="translatedtitle">GPU Implementation of Two-Dimensional <span class="hlt">Rayleigh</span>-Benard Code with High Resolution and Extremely High <span class="hlt">Rayleigh</span> Number</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, C. M.; Sanchez, D. A.; Yuen, D. A.; Wright, G. B.; Barnett, G. A.</p> <p>2010-12-01</p> <p>As computational modeling became prolific throughout the physical sciences community, newer and more efficient ways of processing large amounts of data needed to be devised. One particular method for processing such large amounts of data arose in the form of using a graphics processing unit (GPU) for calculations. Computational scientists were attracted to the GPU as a computational tool as the performance, growth, and availability of GPUs over the past decade increased. Scientists began to utilize the GPU as the sole workhorse for their brute force calculations and modeling. The GPUs, however, were not originally designed for this style of use. As a result, difficulty arose when trying to find a use for the GPU from a scientific standpoint. A lack of parallel programming routines was the main culprit behind the difficulty in programming with a GPU, but with time and a rise in popularity, NVIDIA released a proprietary architecture named Fermi. The Fermi architecture, when used in conjunction with development tools such as CUDA, allowed the programmer easier access to routines that made parallel programming with the NVIDIA GPUs an ease. This new architecture enabled the programmer full access to faster memory, double-precision support, and large amounts of global memory at their fingertips. Our model was based on using a second-order, spatially correct finite difference method and a third order Runge-Kutta time-stepping scheme for studying the 2D <span class="hlt">Rayleigh</span>-Benard code. The code extensively used the CUBLAS routines to do the heavy linear algebra calculations. The calculations themselves were completed using a single GPU, the NVDIA C2070 Fermi, which boasts 6 GB of global memory. The overall scientific goal of our work was to apply the Tesla C2070's computing potential to achieve an onset of flow reversals as a function of increasing large <span class="hlt">Rayleigh</span> numbers. Previous investigations were successful using a smaller grid size of 1000x1999 and a <span class="hlt">Rayleigh</span> number of 10^9. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4405C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4405C"><span id="translatedtitle">Empirical evidence of <span class="hlt">Rayleigh</span> waves in Norcia (central Italy) and their quantitative contribution to ground motion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caffagni, Enrico; Cattaneo, Marco; Bordoni, Paola</p> <p>2016-04-01</p> <p>Spectral ratio techniques, such as the Horizontal-to-Vertical (HV) and Standard (SSR) may exhibit different trends in specific frequency bands when conducted in alluvial basins. A possible explanation of this discrepancy can be provided by the presence of <span class="hlt">Rayleigh</span> oscillations, that are considered responsible of an amplification of the vertical component with respect to the horizontal. We propose a new methodology for the identification of <span class="hlt">Rayleigh</span> waves arrivals, to test on small-size basins. With this procedure, candidate <span class="hlt">Rayleigh</span> waves are localized in time-frequency domain on an instantaneous polarization plane which is constructed by defining the instantaneous maximum vertical and horizontal spectral amplitudes. Validation of the candidate <span class="hlt">Rayleigh</span> arrivals is performed by evaluating the instantaneous ellipticity. This step yields to a quantitative measure of the polarization, providing an indicator of the <span class="hlt">Rayleigh</span> contribution to ground motion. We tested this methodology in the Norcia basin (central Italy) using a 18 selected earthquakes (2.0 < Ml < 5.0) dataset which included seismic events recorded from the L'Aquila sequence (2009). We demonstrate the robustness of our methodology by localizing evidences of <span class="hlt">Rayleigh</span> wave arrivals immediately from (1 s) up to 30 s after the first S-wave group, even for low-magnitude events (Ml < 3.0). The generation of the detected <span class="hlt">Rayleigh</span> waves analyzed in time-frequency range, appears to be magnitude-dependent and in function of the location in the basin. Our quantitative estimate of the <span class="hlt">Rayleigh</span> polarization resulted to be comparable to the HV response value in specific frequency bands, for example in deamplification, demonstrating a plausible connection with <span class="hlt">Rayleigh</span> oscillations. The authors encourage the usage or implementation of similar procedures conducted in basin studies, in order to determine quantitatively the <span class="hlt">Rayleigh</span> contribution to ground motion, for a better characterization of the local seismic response.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20309089','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20309089"><span id="translatedtitle">Infrared (10.6-mum) <span class="hlt">scattering</span> and extinction in laboratory water and ice clouds.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sassen, K</p> <p>1981-01-15</p> <p>Measurements of the angular <span class="hlt">scattering</span> and extinction of IR (10.6-mum) laser radiation in laboratory water and ice clouds are reported and compared to theoretical predictions for spheres and visible (0.633-mum) light <span class="hlt">scattering</span> data. Randomly oriented cloud particles with dimensions ranging from several times smaller to larger than the incident wavelength generated phase functions span the <span class="hlt">Rayleigh</span> and Mie <span class="hlt">scattering</span> domains and illustrate the effects caused by strong internal energy absorption. Dual-wavelength extinction measurements reveal information on the growth and dissipation of laboratory water clouds and the effects of cloud seeding. The remote sensing significance of the findings is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.T51C2887M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.T51C2887M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-wave Tomography Study of Northwestern Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McLellan, M. E.; Audet, P.; Schaeffer, A. J.</p> <p>2015-12-01</p> <p>Due to the ongoing collision of the Yakutat block with the North American plate in southeastern Alaska, a significant amount of deformation is occurring in the northern Canadian Cordillera. The stress transfer associated with the accretion of this terrane is believed to be responsible for the seismicity across this widespread region. Estimates of crustal thickness within the Mackenzie and Richardson Mountains provide constraints on models describing the evolution of crustal roots responsible for supporting such belts that transmit tectonic stresses over long distances (>1000 km); unfortunately, current seismic velocity models used to map crustal thickness have limited resolution due to sparse coverage by seismograph networks. Here we use data from a new regional seismograph network (Yukon-Northwest Seismograph Network - YNSN) as well as permanent stations to map out crustal structure. Crustal thickness variations can be obtained from 3-D seismic velocity models determined from the inversion of surface-wave dispersion data. In this work we present preliminary results of a regional tomography study of northwestern Canada, encompassing the northern Canadian Cordillera, using dispersion curves derived from ambient noise cross-correlations in addition to teleseismic two-station interferometry. We collected all available vertical component seismic data from stations located in the Yukon and surrounding regions from the period between June 2012 and June 2015. Using this data set, we first cross-correlated hour-long segments of the ambient seismic noise between all available stations pairs that share common data availability and obtained virtual <span class="hlt">Rayleigh</span> waves with energy over periods 10-50 s that are predominantly sensitive to crust and uppermost mantle structure. This data set is complemented by <span class="hlt">Rayleigh</span>-wave dispersion measurements, spanning the period range 25—175 s, derived by cross-correlating vertical component data from teleseismic earthquakes (M>5) lying along</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996AnPh...21....1C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996AnPh...21....1C"><span id="translatedtitle">Spectroscopie Raman et <span class="hlt">Rayleigh</span> stimulée des mélasses optiques unidimensionnelles (partie I)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Courtois, Jean-Yves</p> <p></p> <p>In this paper, we present a detailed theoretical investigation of the transmission spectra of a weak probe beam through one-dimensional optical molasses in the so-called linperp lin and σ^+-σ- laser configurations. We show that the resonant structures displayed by the spectra in both situations can be interpreted in terms of stimulated Raman or <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and that they provide important information about the physical properties of the molasses. The paper is divided into two main parts. In order to emphasize the specificity of the stimulated <span class="hlt">scattering</span> processes taking place in optical molasses, we present in a first part the main characteristics of the stimulated Raman and <span class="hlt">Rayleigh</span> processes occurring in conventional atomic and molecular media. Section 2 is devoted to stimulated Raman <span class="hlt">scattering</span>, which is associated with the presence of <span class="hlt">scattering</span> particles having differently populated nondegenerate states. In the case of atomic vapours, which is traditionnally not discussed in textbooks, we demonstrate the occurrence of stimulated Raman transitions between differently populated and light shifted ground state Zeeman sublevels, which manifest themselves on pump-probe transmission spectra in the form of Lorentzian resonances having a width of the order of the optical pumping rate. Section 3 presents a more detailed study of stimulated <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span>, which is associated with the modulation of nonpropagating observables (i.e., of observables whose dynamics does not contain any eigen evolution frequency) by the interference pattern between a probe and a pump field, and with the existence of a physical mechanism responsible for a phase shift between the time and spatial modulation of the observables and the pump-probe excitation. By considering the most generally encountered situation where the phase shift arises from a relaxation mechanism taking place in the material medium, and where stimulated <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> manifests itself in the form of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RaPC..126...49G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RaPC..126...49G"><span id="translatedtitle"><span class="hlt">Scattering</span> intensities for a white beam (120 kV) presenting a semi-empirical model to preview <span class="hlt">scattered</span> beams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonçalves, O. D.; Boldt, S.; Kasch, K. U.</p> <p>2016-09-01</p> <p>This work aims at measuring the <span class="hlt">scattering</span> cross sections for white beams and the verification of a semi-empirical model predicting <span class="hlt">scattered</span> energy spectra of an X-ray beam produced by an industrial X-ray tube (Pantack Sievert, 120 kV, tungsten target) incident on a water sample. Both, theoretical and semi-empirical results presented are based on the form factor approach with results well corresponding to performed measurements. The elastic (<span class="hlt">Rayleigh</span>) <span class="hlt">scattering</span> cross sections are based on Thomson <span class="hlt">scattering</span> with a form factor correction as published by Morin (1982). The inelastic (Compton) contribution is based on the Klein Nishina equation (Klein and Nishina, 1929) multiplied by the incoherent <span class="hlt">scattering</span> factors calculated by Hubbel et al. (1975). Two major results are presented: first, the experimental integrated in energy cross sections corresponds with theoretical cross sections obtained at the mean energy of the measured <span class="hlt">scattered</span> spectra at a given angle. Secondly, the measured <span class="hlt">scattered</span> spectra at a given angle correspond to those obtained utilizing the semi-empirical model as proposed here. A good correspondence of experimental results and model predictions can be shown. The latter, therefore, proves to be a useful method to calculate the <span class="hlt">scattering</span> contributions in a number of applications as for example cone beam tomography.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DPPPP9140C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DPPPP9140C"><span id="translatedtitle">Magnetic <span class="hlt">Rayleigh</span>-Taylor Instability with Biermann Battery Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chou, Chuan-Chih (Jason); Fryxell, Bruce; Drake, R.; van der Holst, Bart</p> <p>2011-10-01</p> <p>Recently, unexpected morphology has been observed in high-energy <span class="hlt">Rayleigh</span>-Taylor experiments. In these experiments with 3D initial perturbations, the spikes lack the mushroom cap observed in 2D or low-energy counterparts. It is suspected that magnetic field generated by Biermann battery may be responsible for this unusual morphology. In order to estimate the magnitude of the magnetic field due to Biermann battery effect under the experimental circumstances, we performed preliminary simulations using CRASH and its recent implementation of Biermann battery term. Although limited by the lack of corresponding dissipation term, we are able to obtain the upper limit of the magnetic field present in the experiment. We will discuss its implication in the context of the plausibility of the Biermann battery hypothesis. Work supported by the Predictive Sciences Academic Alliances Program in USDOE NNSA-ASC (grant DE-FC52-08NA28616), and by the University of Michigan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22068803','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22068803"><span id="translatedtitle">The cylindrical magnetic <span class="hlt">Rayleigh</span>-Taylor instability for viscous fluids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chambers, K.; Forbes, L. K.</p> <p>2012-10-15</p> <p>This paper considers a cylindrical <span class="hlt">Rayleigh</span>-Taylor instability, in which a heavy fluid surrounds a light fluid, and gravity is directed radially inwards. A massive object is located at the centre of the light fluid, and it behaves like a line dipole both for fluid flow and magnetic field strength. The initially circular interface between the two conducting fluids evolves into plumes, dependent on the magnetic and fluid dipole strengths and the nature of the initial disturbance to the interface. A spectral method is presented to solve the time-dependent interface shapes, and results are presented and discussed. Bipolar solutions are possible, and these are of particular relevance to astrophysics. The solutions obtained resemble structures of some HII regions and nebulae.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DPPGO5007R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DPPGO5007R"><span id="translatedtitle">Qualitative and quantitative features of <span class="hlt">Rayleigh</span>-Taylor mixing dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramaprabhu, Praveen; Karkhanis, Varad; Lawrie, Andrew; Bhowmick, Aklant; Abarzhi, Snezhana; RTI Collaboration</p> <p>2015-11-01</p> <p>We consider dynamics of <span class="hlt">Rayleigh</span>-Taylor (RT) flow in a large aspect ratio three-dimensional domain with square symmetry in the plane for fluids with contrasting densities. In order to quantify the interface evolution from a small amplitude single-mode initial perturbation to advanced stage of RT mixing, we apply numerical simulations using the MOBILE code, theoretical analyses, including group theory and momentum model, as well as parameters describing the interplay between acceleration and turbulence. We find: In RT flow, the fluid motion is intense near the interface and is negligible far from the interface. At late times the growth rates of RT bubbles and spikes may increase without a corresponding increase of length-scales in the direction normal to acceleration. The parameters describing the interplay between acceleration and turbulence in RT mixing are shown to scale well with the flow Reynolds number and Froude number.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21929106','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21929106"><span id="translatedtitle">Convection in an ideal gas at high <span class="hlt">Rayleigh</span> numbers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tilgner, A</p> <p>2011-08-01</p> <p>Numerical simulations of convection in a layer filled with ideal gas are presented. The control parameters are chosen such that there is a significant variation of density of the gas in going from the bottom to the top of the layer. The relations between the <span class="hlt">Rayleigh</span>, Peclet, and Nusselt numbers depend on the density stratification. It is proposed to use a data reduction which accounts for the variable density by introducing into the scaling laws an effective density. The relevant density is the geometric mean of the maximum and minimum densities in the layer. A good fit to the data is then obtained with power laws with the same exponent as for fluids in the Boussinesq limit. Two relations connect the top and bottom boundary layers: The kinetic energy densities computed from free fall velocities are equal at the top and bottom, and the products of free fall velocities and maximum horizontal velocities are equal for both boundaries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11088876','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11088876"><span id="translatedtitle">Asymmetric squares as standing waves in <span class="hlt">rayleigh</span>-Benard convection</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Das; Ghosal; Kumar</p> <p>2000-09-01</p> <p>Possibility of thermal convection in the form of asymmetric squares in a thin layer of Boussinesq fluids of large lateral extension confined between stress-free and conducting flat boundaries is investigated numerically using a seven mode Lorenz-like model. For fluids with moderate and high Prandtl numbers (4<sigma<20) and in a narrow window of high <span class="hlt">Rayleigh</span> numbers (12<R/R(c)<15), which depend on Prandtl number, the stationary rolls become unstable and asymmetric squares appear as standing waves at the onset of secondary instability. Asymmetric squares, two-dimensional rolls, and again asymmetric squares with their corners shifted by half a wavelength form a stable limit cycle. The oscillatory bifurcation is supercritical. PMID:11088876</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840046202&hterms=Seal+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSeal%2Bdesign','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840046202&hterms=Seal+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSeal%2Bdesign"><span id="translatedtitle">Design analysis of <span class="hlt">Rayleigh</span>-step floating-ring seals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Artiles, A.; Shapiro, W.; Jones, H. F.</p> <p>1983-01-01</p> <p>The analysis and design of a 50-mm diameter floating-ring helium buffer seal are described. The seal rings incorporated <span class="hlt">Rayleigh</span>-step lift pads to provide hydrodynamic forces to separate the rings from the shaft. Maximum surface speed is 183 m/s (600 fps) and maximum buffer gas pressure is 1389 kPa (200 psia). An operating range map was computed as a function of speed and pressure. Contradictory problems arise due to excessive friction preventing ring tracking at low-speed, high-pressure conditions and insufficent friction to retard inertia driven motions at high-speed, low-pressure conditions. Steady-state and dynamic analyses and performance are described, as well as the results of thermal studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17298019','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17298019"><span id="translatedtitle">Charge-induced <span class="hlt">Rayleigh</span> instabilities in small gold rods.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Novo, Carolina; Mulvaney, Paul</p> <p>2007-02-01</p> <p>It is demonstrated that the addition of electrons to gold nanorods with aspect ratios ranging from 2 to 4 leads to an initial blue-shift in the absorption spectrum due to the increasing surface plasmon frequency of the electron gas. However, at longer times, there are changes in particle morphology induced by the surface charge. In the case of smaller injected electron densities, the surface plasmon band red-shifts as the end caps of the rods undergo increased faceting and develop {111} faces. In the case of higher electron densities, the rods undergo fragmentation into clouds of smaller spheres. These secondary processes and fragmentation are postulated to be a direct result of crossing the <span class="hlt">Rayleigh</span> threshold.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22410401','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22410401"><span id="translatedtitle">Collisional effects on <span class="hlt">Rayleigh</span>-Taylor-induced magnetic fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manuel, M. J.-E.; Flaig, M.; Plewa, T.; Li, C. K.; Séguin, F. H.; Frenje, J. A.; Casey, D. T.; Petrasso, R. D.; Hu, S. X.; Betti, R.; Hager, J.; Meyerhofer, D. D.; Smalyuk, V.</p> <p>2015-05-15</p> <p>Magnetic-field generation from the <span class="hlt">Rayleigh</span>-Taylor (RT) instability was predicted more than 30 years ago, though experimental measurements of this phenomenon have only occurred in the past few years. These pioneering observations demonstrated that collisional effects are important to B-field evolution. To produce fields of a measurable strength, high-intensity lasers irradiate solid targets to generate the nonaligned temperature and density gradients required for B-field generation. The ablation process naturally generates an unstable system where RT-induced magnetic fields form. Field strengths inferred from monoenergetic-proton radiographs indicate that in the ablation region diffusive effects caused by finite plasma resistivity are not negligible. Results from the first proof-of-existence experiments are reviewed and the role of collisional effects on B-field evolution is discussed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhyE...56..357C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhyE...56..357C"><span id="translatedtitle">Free vibration of rectangular nanoplates using <span class="hlt">Rayleigh</span>-Ritz method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chakraverty, S.; Behera, Laxmi</p> <p>2014-02-01</p> <p>Vibration analysis of isotropic rectangular nanoplates based on the classical plate theory in conjunction with Eringen's nonlocal elasticity theory is considered. Nanoplates are one of the structural units that are used in nanoscale applications. In this study, <span class="hlt">Rayleigh</span>-Ritz method with algebraic polynomial displacement function is used to solve the vibration problem of isotropic rectangular nanoplates subjected to different boundary conditions. The advantage of the method is that one can easily handle the specified boundary conditions at the edges. A comparison of the results with those available in the literature has been made. The proposed method is also validated by convergence studies. Frequency parameters are given for different nonlocality parameters, length of nanoplates and boundary conditions. The study highlights that nonlocality effects increase with the increase in mode number and the influence of nonlocal effects becomes increasingly pronounced for higher order vibration modes. Three-dimensional mode shapes for the specified nanoplates have also been presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Nonli..29.3309F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Nonli..29.3309F"><span id="translatedtitle">Ergodicity in randomly forced <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Földes, J.; Glatt-Holtz, N. E.; Richards, G.; Whitehead, J. P.</p> <p>2016-11-01</p> <p>We consider the Boussinesq approximation for <span class="hlt">Rayleigh</span>-Bénard convection perturbed by an additive noise and with boundary conditions corresponding to heating from below. In two space dimensions, with sufficient stochastic forcing in the temperature component and large Prandtl number Pr  >  0, we establish the existence of a unique ergodic invariant measure. In three space dimensions, we prove the existence of a statistically invariant state, and establish unique ergodicity for the infinite Prandtl Boussinesq system. Throughout this work we provide streamlined proofs of unique ergodicity which invoke an asymptotic coupling argument, a delicate usage of the maximum principle, and exponential martingale inequalities. Lastly, we show that the background method of Constantin and Doering (1996 Nonlinearity 9 1049-60) can be applied in our stochastic setting, and prove bounds on the Nusselt number relative to the unique invariant measure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5260M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5260M"><span id="translatedtitle">Plasma transport driven by the <span class="hlt">Rayleigh</span>-Taylor instability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, X.; Delamere, P. A.; Otto, A.</p> <p>2016-06-01</p> <p>Two important differences between the giant magnetospheres (i.e., Jupiter's and Saturn's magnetospheres) and the terrestrial magnetosphere are the internal plasma sources and the fast planetary rotation. Thus, there must be a radially outward flow to transport the plasma to avoid infinite accumulation of plasma. This radial outflow also carries the magnetic flux away from the inner magnetosphere due to the frozen-in condition. As such, there also must be a radial inward flow to refill the magnetic flux in the inner magnetosphere. Due to the similarity between <span class="hlt">Rayleigh</span>-Taylor (RT) instability and the centrifugal instability, we use a three-dimensional RT instability to demonstrate that an interchange instability can form a convection flow pattern, locally twisting the magnetic flux, consequently forming a pair of high-latitude reconnection sites. This process exchanges a part of the flux tube, thereby transporting the plasma radially outward without requiring significant latitudinal convection of magnetic flux in the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvE..81d1308V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvE..81d1308V"><span id="translatedtitle">Size invariance of the granular <span class="hlt">Rayleigh</span>-Taylor instability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinningland, Jan Ludvig; Johnsen, Øistein; Flekkøy, Eirik G.; Toussaint, Renaud; Måløy, Knut Jørgen</p> <p>2010-04-01</p> <p>The size scaling behavior of the granular <span class="hlt">Rayleigh</span>-Taylor instability [J. L. Vinningland , Phys. Rev. Lett. 99, 048001 (2007)] is investigated experimentally, numerically, and theoretically. An upper layer of grains displaces a lower gap of air by organizing into dense fingers of falling grains separated by rising bubbles of air. The dependence of these structures on the system and grain sizes is investigated. A spatial measurement of the finger structures is obtained by the Fourier power spectrum of the wave number k . As the size of the grains increases the wave number decreases accordingly which leaves the dimensionless product of wave number and grain diameter, dk , invariant. A theoretical interpretation of the invariance, based on the scaling properties of the model equations, suggests a gradual breakdown of the invariance for grains smaller than ˜70μm or greater than ˜570μm in diameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.462..565C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.462..565C"><span id="translatedtitle">The magnetic <span class="hlt">Rayleigh</span>-Taylor instability in astrophysical discs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Contopoulos, I.; Kazanas, D.; Papadopoulos, D. B.</p> <p>2016-10-01</p> <p>This is our first study of the magnetic <span class="hlt">Rayleigh</span>-Taylor instability at the inner edge of an astrophysical disc around a central back hole. We derive the equations governing small-amplitude oscillations in general relativistic ideal magnetodydrodynamics and obtain a criterion for the onset of the instability. We suggest that static disc configurations where magnetic field is held by the disc material are unstable around a Schwarzschild black hole. On the other hand, we find that such configurations are stabilized by the space-time rotation around a Kerr black hole. We obtain a crude estimate of the maximum amount of poloidal magnetic flux that can be accumulated around the centre, and suggest that it is proportional to the black hole spin. Finally, we discuss the astrophysical implications of our result for the theoretical and observational estimations of the black hole jet power.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20736593','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20736593"><span id="translatedtitle">Recent advances in the turbulent <span class="hlt">Rayleigh</span>-Taylor instability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dimonte, Guy; Ramaprabhu, P.; Youngs, D.L.; Andrews, M.J.; Rosner, R.</p> <p>2005-05-15</p> <p>In the turbulent <span class="hlt">Rayleigh</span>-Taylor instability, the light fluid penetrates the heavy fluid as bubbles with a diameter D{sub b} and amplitude h{sub b} that grow self-similarly D{sub b}{proportional_to}h{sub b}{approx}{alpha}{sub b}A gt{sup 2} where A is Atwood number, g is acceleration, and t is time. Experiments measure an acceleration constant {alpha}{sub b}{approx}0.04-0.08 whereas the highest resolution three-dimensional numerical simulations obtain {alpha}{sub b}{approx}0.02-0.03 with idealized initial conditions. This paper reconciles this apparent discrepancy with new simulations that quantify the importance of initial conditions on {alpha}{sub b}. The results compare favorably with experiments and a model based on self-similar bubble dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvE..93b3104M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhRvE..93b3104M&link_type=ABSTRACT"><span id="translatedtitle">Viscous <span class="hlt">Rayleigh</span>-Taylor instability in spherical geometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mikaelian, Karnig O.</p> <p>2016-02-01</p> <p>We consider viscous fluids in spherical geometry, a lighter fluid supporting a heavier one. Chandrasekhar [Q. J. Mech. Appl. Math. 8, 1 (1955), 10.1093/qjmam/8.1.1] analyzed this unstable configuration providing the equations needed to find, numerically, the exact growth rates for the ensuing <span class="hlt">Rayleigh</span>-Taylor instability. He also derived an analytic but approximate solution. We point out a weakness in his approximate dispersion relation (DR) and offer a somewhat improved one. A third DR, based on transforming a planar DR into a spherical one, suffers no unphysical predictions and compares reasonably well with the exact work of Chandrasekhar and a more recent numerical analysis of the problem [Terrones and Carrara, Phys. Fluids 27, 054105 (2015), 10.1063/1.4921648].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21929106','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21929106"><span id="translatedtitle">Convection in an ideal gas at high <span class="hlt">Rayleigh</span> numbers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tilgner, A</p> <p>2011-08-01</p> <p>Numerical simulations of convection in a layer filled with ideal gas are presented. The control parameters are chosen such that there is a significant variation of density of the gas in going from the bottom to the top of the layer. The relations between the <span class="hlt">Rayleigh</span>, Peclet, and Nusselt numbers depend on the density stratification. It is proposed to use a data reduction which accounts for the variable density by introducing into the scaling laws an effective density. The relevant density is the geometric mean of the maximum and minimum densities in the layer. A good fit to the data is then obtained with power laws with the same exponent as for fluids in the Boussinesq limit. Two relations connect the top and bottom boundary layers: The kinetic energy densities computed from free fall velocities are equal at the top and bottom, and the products of free fall velocities and maximum horizontal velocities are equal for both boundaries. PMID:21929106</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19905434','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19905434"><span id="translatedtitle">Linear analysis of incompressible <span class="hlt">Rayleigh</span>-Taylor instability in solids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piriz, A R; Cela, J J López; Tahir, N A</p> <p>2009-10-01</p> <p>The study of the linear stage of the incompressible <span class="hlt">Rayleigh</span>-Taylor instability in elastic-plastic solids is performed by considering thick plates under a constant acceleration that is also uniform except for a small sinusoidal ripple in the horizontal plane. The analysis is carried out by using an analytical model based on the Newton second law and it is complemented with extensive two-dimensional numerical simulations. The conditions for marginal stability that determine the instability threshold are derived. Besides, the boundary for the transition from the elastic to the plastic regime is obtained and it is demonstrated that such a transition is not a sufficient condition for instability. The model yields complete analytical solutions for the perturbation amplitude evolution and reveals the main physical process that governs the instability. The theory is in general agreement with the numerical simulations and provides useful quantitative results. Implications for high-energy-density-physics experiments are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21294422','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21294422"><span id="translatedtitle">Linear analysis of incompressible <span class="hlt">Rayleigh</span>-Taylor instability in solids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Piriz, A. R.; Lopez Cela, J. J.; Tahir, N. A.</p> <p>2009-10-15</p> <p>The study of the linear stage of the incompressible <span class="hlt">Rayleigh</span>-Taylor instability in elastic-plastic solids is performed by considering thick plates under a constant acceleration that is also uniform except for a small sinusoidal ripple in the horizontal plane. The analysis is carried out by using an analytical model based on the Newton second law and it is complemented with extensive two-dimensional numerical simulations. The conditions for marginal stability that determine the instability threshold are derived. Besides, the boundary for the transition from the elastic to the plastic regime is obtained and it is demonstrated that such a transition is not a sufficient condition for instability. The model yields complete analytical solutions for the perturbation amplitude evolution and reveals the main physical process that governs the instability. The theory is in general agreement with the numerical simulations and provides useful quantitative results. Implications for high-energy-density-physics experiments are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25314524','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25314524"><span id="translatedtitle"><span class="hlt">Rayleigh</span>-Bénard convection with uniform vertical magnetic field.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Basak, Arnab; Raveendran, Rohit; Kumar, Krishna</p> <p>2014-09-01</p> <p>We present the results of direct numerical simulations of <span class="hlt">Rayleigh</span>-Bénard convection in the presence of a uniform vertical magnetic field near instability onset. We have done simulations in boxes with square as well as rectangular cross sections in the horizontal plane. We have considered the horizontal aspect ratio η=L(y)/L(x)=1 and 2. The onset of the primary and secondary instabilities are strongly suppressed in the presence of the vertical magnetic field for η=1. The Nusselt number Nu scales with the <span class="hlt">Rayleigh</span> number Ra close to the primary instability as [{Ra-Ra(c)(Q)}/Ra(c)(Q)](0.91), where Ra(c)(Q) is the threshold for onset of stationary convection at a given value of the Chandrasekhar number Q. Nu also scales with Ra/Q as (Ra/Q)(μ). The exponent μ varies in the range 0.39≤μ≤0.57 for Ra/Q≥25. The primary instability is stationary as predicted by Chandrasekhar. The secondary instability is temporally periodic for Pr=0.1 but quasiperiodic for Pr=0.025 for moderate values of Q. Convective patterns for higher values of Ra consist of periodic, quasiperiodic, and chaotic wavy rolls above the onset of the secondary instability for η=1. In addition, stationary as well as time-dependent cross rolls are observed, as Ra is further raised. The ratio r(o)/Pr is independent of Q for smaller values of Q. The delay in the onset of the oscillatory instability is significantly reduced in a simulation box with η=2. We also observe inclined stationary rolls for smaller values of Q for η=2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JFM...773..395P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JFM...773..395P"><span id="translatedtitle">Kinetic energy transport in <span class="hlt">Rayleigh</span>-Bénard convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petschel, K.; Stellmach, S.; Wilczek, M.; Lülff, J.; Hansen, U.</p> <p>2015-06-01</p> <p>The kinetic energy balance in <span class="hlt">Rayleigh</span>--B\\'{e}nard convection is investigated for the Prandtl number range $0.01\\le Pr \\le 150$ and for fixed <span class="hlt">Rayleigh</span> number $Ra=5\\cdot10^{6}$. The kinetic energy balance is divided into a dissipation, a production and a flux term. We discuss profiles of all terms and find that the different contributions to the energy balance can be spatially separated into regions where kinetic energy is produced and where kinetic energy is dissipated. Analysing the Prandtl number dependence of the kinetic energy balance, we show that the height-dependence of the mean viscous dissipation is closely related to the flux of kinetic energy. We show that the flux of kinetic energy can be divided into four additive contributions, each representing a different elementary physical process (advection, buoyancy, normal viscous stresses and viscous shear stresses). The behaviour of these individual flux contributions is found to be surprisingly rich and exhibits a pronounced Prandtl number dependence. Different flux contributions dominate the kinetic energy transport at different depth, such that a comprehensive discussion requires a decomposition of the domain into a considerable number of sub-layers. On a less detailed level, our results reveal that advective kinetic energy fluxes play a key role in balancing the near-wall dissipation at low Prandtl number, whereas normal viscous stresses are particularly important at high Prandtl number. Finally, our work reveals that classical velocity boundary layers are deeply connected to the kinetic energy transport, but fail to correctly represent regions of enhanced viscous dissipation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......172W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......172W"><span id="translatedtitle">Polarized light <span class="hlt">scattering</span> from individual semiconductor nanowires</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Jian</p> <p></p> <p>This thesis addresses the light <span class="hlt">scattering</span>, particularly Raman and <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> from quasi one dimensional semiconductor nanowires, such as Zn1-xMnxS and GaP nanowires. Many of the results stem from measurements of individual wires. Four original works are presented in the thesis: (1) The growth of diluted magnetic semiconductor (DMS) Zn1-xMnxS (0≤x<0.6) nanowires using a three-zone furnace and two solid sources is reported (Chapter 2.4). The vibrational properties of the DMS nanowires with different Zn/Mn ratios were studied by correlating their Raman <span class="hlt">scattering</span> spectra with the composition and structure measured by x-Ray energy dispersive spectroscopy (XEDS) and selected area electron diffraction (SAD). We find that the transverse optical (TO) phonon band disappears at the lowest Mn concentrations, while the longitudinal optical (LO) phonon band position was found insensitive to x. Three additional Raman bands were observed between the ZnS q=0 TO and LO phonons when Mn atoms were present in the nanowires (Chapter 5); (2) Polarized Raman <span class="hlt">scattering</span> on individual crystalline GaP nanowires with diameters 40 individual crystalline GaP nanowires with diameters 40<d<600 nm are systematically investigated. At small diameters, d<70 nm, the nanowires are found to act like a nearly perfect dipole antenna and the bulk Raman selection rules are masked leading to a polarized <span class="hlt">scattering</span> intensity function I(theta) ˜ cos4theta where theta is the angle between nanowire axis and the incident laser polarization. For larger diameter (70<d<600nm) nanowires, a model based on the interplay between photon confinement and bulk Raman <span class="hlt">scattering</span> are proposed to explain the experimental data. This work realizes a fundamental understanding of Raman <span class="hlt">scattering</span> in semiconductor nanowires and furthermore, the antenna effects are essential to the analysis of all electro-optic effects in small diameter filaments (Chapter 7); (3) Results of polarized <span class="hlt">Rayleigh</span> back-<span class="hlt">scattering</span> studies are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDR27001E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDR27001E"><span id="translatedtitle">Multiple light <span class="hlt">scattering</span> methods for multiphase flow diagnostics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Estevadeordal, Jordi</p> <p>2015-11-01</p> <p>Multiphase flows of gases and liquids containing droplets, bubbles, or particulates present light <span class="hlt">scattering</span> imaging challenges due to the interference from each phase, such as secondary reflections, extinctions, absorptions, and refractions. These factors often prevent the unambiguous detection of each phase and also produce undesired beam steering. The effects can be especially complex in presence of dense phases, multispecies flows, and high pressure environments. This investigation reports new methods for overcoming these effects for quantitative measurements of velocity, density, and temperature fields. The methods are based on light <span class="hlt">scattering</span> techniques combining Mie and filtered <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and light extinction analyses and measurements. The optical layout is designed to perform multiple property measurements with improved signal from each phase via laser spectral and polarization characterization, etalon decontamination, and use of multiple wavelengths and imaging detectors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/766821','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/766821"><span id="translatedtitle">Horizontal Thomson <span class="hlt">Scattering</span> Systems for DIII-D and SSPX</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nilson, D.G.; Hill, D.N.; Wood, R.D.; McClean, H.; Moeller, J.M.; Labik, G.; Carlstron, T.N.; Bray, B.; Hsieh, C.L.</p> <p>1999-08-01</p> <p>DIII-D--Three of the seven existing core Thomson <span class="hlt">scattering</span> laser beams were redirected to probe the previously unmeasured central region of the DIII-D plasma. Modifications to the existing collection optics system and support tower were made to inject the lasers and collect <span class="hlt">scattered</span> light in this new extended region. Stray light levels were reduced to acceptable levels to permit <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> calibration on five of the six new channels, indicating that the new in-vessel dump operates well. Measurements of the plasma temperature and density from the plasma edge to the center are now possible. Peaked density profiles are now observed in this new measurement region. SSPX--We have completed the design and installation of a 10-spatial channel Thomson <span class="hlt">scattering</span> system to measure the plasma temperature and density profile on SSPX. A single-pulsed YAG laser operating at 0.7 J and 8 ns is used to <span class="hlt">scatter</span> photons into a 7-element collection optic that provides a spatial resolution of 1.5 cm at the outer plasma edge and 7.5 cm at the inner edge of a .5 m radius spheromak plasma. The collected light is then analyzed by a 4-channel interference filtered polychromator which has been optimized to measure temperatures between 2 eV and 2 keV and densities as low as 1 x 10{sup 12} cm{sup 3}. We use an in-vessel beam dump and a series of entrance and exit baffles to reduce the stray laser light and provide for an absolute density calibration by <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> in argon gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PPCF...57a4026C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PPCF...57a4026C"><span id="translatedtitle">Thomson <span class="hlt">scattering</span> on non-equilibrium low density plasmas: principles, practice and challenges</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbone, Emile; Nijdam, Sander</p> <p>2015-01-01</p> <p>In this paper, we review the main challenges related to laser Thomson <span class="hlt">scattering</span> on low temperature plasmas. The main features of the triple grating spectrometer used to discriminate Thomson and Raman <span class="hlt">scattering</span> signals from <span class="hlt">Rayleigh</span> <span class="hlt">scattering</span> and stray light are presented. The main parameters influencing the detection limit of Thomson <span class="hlt">scattering</span> are reviewed. Laser stray light and plasma emission are two limiting factors, but Raman <span class="hlt">scattering</span> from molecules inside the plasma will further decrease it. In the case of non-thermal plasmas at high pressure, Thomson <span class="hlt">scattering</span> is the only technique which allows us to obtain the electron density without any prior knowledge of the plasma properties. Moreover, very high 3D spatial and temporal resolutions can easily be achieved. However, special care still needs to be taken to verify that Thomson <span class="hlt">scattering</span> is non intrusive. The mechanisms that will lead to possible measurement errors are discussed. The wavelength-resolved <span class="hlt">scattering</span> signal also allows us to get direct information about the electron energy distribution function in the case of incoherent light <span class="hlt">scattering</span>. Finally, we discuss some recent applications of Thomson <span class="hlt">scattering</span> on atmospheric pressure plasma jets, but also in the field of electron collision kinetics. Thomson <span class="hlt">scattering</span> can be applied on atomic but also molecular plasmas. In the latter case, one needs to take into account the possible contribution of rotational Raman <span class="hlt">scattering</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983PhDT........56R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983PhDT........56R"><span id="translatedtitle">Microparticle and Cell Characterization Using Acoustic <span class="hlt">Scattering</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roos, Mark Schaefer</p> <p></p> <p>A technique is presented for measuring physical properties of particles with radii from one to five microns. Tone bursts of 30 MHz center frequency are <span class="hlt">scattered</span> by single particles as they are carried by a coaxial jet flow past three focused acoustic transducers (one sender and two receivers). The <span class="hlt">scattered</span> pressure is measured simultaneously at two angles, which allows the compressibility and density of the particles to be calculated given the volume of the particles and the density and compressibility of the host liquid using <span class="hlt">Rayleigh</span>'s theory for long wavelength acoustic <span class="hlt">scattering</span>. Because the particles are measured one at a time, statistical distributions of their properties may be determined. The device is calibrated using particles whose properties are known. A study was conducted on human red blood cells in hosts of different tonicity. Density and compressibility values obtained in these experiments are compared with a model accounting for changes in red cell properties due to variations in cell water content. Other studies were conducted using polystyrene and polystyrene divinylbenzene spheres. This technique is well suited to in vitro measurement of properties of biological cells. Applications are discussed, with emphasis on the study of red blood cells.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20168450','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20168450"><span id="translatedtitle">Quasi-elastic light <span class="hlt">scattering</span> from structured particles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, S H; Holz, M; Tartaglia, P</p> <p>1977-01-01</p> <p>We present a formulation by which the <span class="hlt">scattered</span> field correlation function of a nonstationary structured particle can be calculated. Specifically, we consider the case of micron-size bacteria, where the <span class="hlt">Rayleigh</span>- Gans-Debye approximation may be used to evaluate the correlation function. We show that the width of the intensity correlation spectrum (as measured, for example, by the photon correlation technique) exhibits I an oscillatory behavior which is characteristic of the interference pattern produced by the internal structure. Two cases are of interest: diffusion and motility are considered in detail, and some evidence of the predicted behavior is shown from the photon correlation measurement of E. coli bacteria. PMID:20168450</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15006505','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15006505"><span id="translatedtitle">Ablation front <span class="hlt">rayleigh</span> taylor dispersion curve in indirect drive</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Budil, K S; Lasinski, B; Edwards, M J; Wan, A S; Remington, B A; Weber, S V; Glendinning, S G; Suter, L; Stry, P</p> <p>2000-11-17</p> <p>The <span class="hlt">Rayleigh</span>-Taylor (RT) instability, which occurs when a lower-density fluid accelerates a higher-density layer, is common in nature. At an ablation front a sharp reduction in the growth rate of the instability at short wave-lengths can occur, in marked contrast to the classical case where growth rates are highest at the shortest wavelengths. Theoretical and numerical investigations of the ablative RT instability are numerous and differ considerably on the level of stabilization expected. We present here the results of a series of laser experiments designed to probe the roll-over and cutoff region of the ablation-front RT dispersion curve in indirect drive. Aluminum foils with imposed sinusoidal perturbations ranging in wavelength from 10 to 70 pm were ablatively accelerated with a radiation drive generated in a gold cylindrical hohlraum. A strong shock wave compresses the package followed by an {approx}2 ns period of roughly constant acceleration and the experiment is diagnosed via face-on radiography. Perturbations with wavelengths {ge} 20 {micro}m experienced substantial growth during the acceleration phase while shorter wavelengths showed a sharp drop off in overall growth. These experimental results compared favorably to calculations with a 2-D radiation-hydrodynamics code, however, the growth is significantly affected by the rippled shock launched by the drive. We performed numerical simulations to elucidate the influence of the rippled shock wave on the eventual growth of the perturbations, allowing comparisons to the analytic model developed by Betti et al. This combination of experiments, simulations and analytic modeling illustrates the qualitative simplicity yet quantitative complexity of the compressible RT instability. We have measured the <span class="hlt">Rayleigh</span>-Taylor (RT) dispersion curve for a radiatively-driven sample in a series of experiments on the Nova laser facility. Planar aluminum foils were ablatively-accelerated and the subsequent perturbation growth</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhDT.......279S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhDT.......279S"><span id="translatedtitle"><span class="hlt">Rayleigh</span> streaming simulation using the vorticity transport equation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sastrapradja, Debbie</p> <p></p> <p>One part of understanding thermoacoustic devices involves studying a physical phenomenon called acoustic streaming, a steady fluid flow induced by oscillating acoustic waves. Current numerical calculation of acoustic streaming can involve major computing time and resources. In order to develop a quicker model, the vorticity transport equation (VTE) is used. The goal of using the VTE is to obtain a relatively fast solution with minimal computational resources, which in this case is a single PC. The intent of this method is that it is used in the early design stage of thermoacoustic devices where preliminary (although less detailed) fast results are desired. It is also preferred that the computing power be minimized as not to tie up other resources for the optimized design of thermoacoustic devices. The most well known type of acoustic streaming, <span class="hlt">Rayleigh</span> streaming, is simulated using the VTE method. A clustered grid is utilized to capture the boundary layer effect on the acoustic streaming. The governing equations used are the VTE, Poisson's equation, and an equation that relates the stream function with the velocity. The outline of the method of calculation involves (i) generating a clustered grid and ensuring there are enough points in the boundary layer, (ii) transforming the clustered grid into the uniform computational grid, (iii) transforming the governing equations to account for the clustering, (iv) calculating the vorticity and the stream function at each grid point using a Direct Method, and (v) calculating the acoustic streaming velocity using the stream function. Steps (iv) through (v) are repeated until the solution converges. It is demonstrated that the VTE method to calculate <span class="hlt">Rayleigh</span> streaming works well. There are two cases being simulated in the research, a parallel plate case and a cylindrical tube case. The numerical results agree with the analytical results for both cases, although there are some discrepancies in the cylindrical tube case. At</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002AGUFMGP12A1092G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002AGUFMGP12A1092G&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Rayleigh</span> Number for Core Convection: Three Independent Estimates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gubbins, D.</p> <p>2002-12-01</p> <p>The <span class="hlt">Rayleigh</span> number (Ra) for the Earth's core is a dimensionless measure of the heat flux crossing the core-mantle boundary (CMB). Recent calculations on the properties of liquid iron mixtures at core pressures and temperatures have provided reliable data for thermodynamic estimates of core heat flow, all of which suggests that heat budget is rather tight: Either the core is cooling so fast that the inner core is young and formed only 1~Gyr ago, or the core contains substantial radiogenic heating from K40. These heat flow estimates translate into Ra≈ 1000Rac, the critical value for convection assuming a magnetic field of typical core strength and turbulent values of viscosity and thermal diffusivity [Gubbins, Phys. Earth Planet. Int., 128 3--12, 2001]. Magnetic fields facilitate convection in a rotating system; for core parameters they lower Rac by a factor of about 1000. The estimate of Ra is therefore close to the marginal value, the minimum heat flux needed for convection in the core if the magnetic field were absent. Another estimate was made by Jones [Phil. Trans. R. Soc. Lond., 358 871--872, 2000] by considering the heat transported by convection in the core. This gives a similar value of 500Rac; it is independent because the basic information used is a typical estimate of core flow speed rather than CMB heat flux. The third estimate comes from the observation of low secular variation in the Pacific. Seismic tomography shows low velocity, probably hot material, at the base of the mantle in the Pacific region. Using this as a boundary condition for simple convection calculations shows that the usual Busse rolls are completely suppressed in the Pacific when lateral variations are 30%\\ of the mean heat flux and total heat flux is just above critical. While much work needs to be done on extending these simple calculations, they imply that the heat flux from the Pacific region is subadiabatic. Converting the variations of seismic velocity within D'' to heat</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.S22C..03D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.S22C..03D"><span id="translatedtitle">Imaging <span class="hlt">Rayleigh</span> Wave Attenuation Beneath North America with USArray</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dalton, C. A.; Bao, X.; Jin, G.; Gaherty, J. B.</p> <p>2015-12-01</p> <p>The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity. Surface-wave amplitudes are sensitive to factors in addition to attenuation, including source excitation, focusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, <span class="hlt">Rayleigh</span> wave travel time and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique. We consider three different approaches for separating the effects of local site amplification and attenuation on the amplitude measurements. The attenuation values determined with these three approaches contain the same first-order features, which gives us confidence that these features are robust: high attenuation in the western U.S. and low attenuation in the central and eastern U.S., with slightly higher attenuation along the eastern seaboard. However, we also identify several areas where we suspect the imaged attenuation values reflect unmodelled focusing effects rather than anelastic attenuation. We therefore identify attenuation values that are likely contaminated by unmodelled focusing effects using the Laplacian of the phase-velocity map, eliminate those values, and generate 2-D attenuation maps through a regional average of the remaining values. We also investigate the range of intrinsic shear-attenuation values that are suggested by the <span class="hlt">Rayleigh</span> wave attenuation maps at periods between 40 and 80 s. This preliminary model is the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JPhCS.534a2054S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JPhCS.534a2054S&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Rayleigh</span> Taylor instability of two superposed compressible fluids in un-magnetized plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, P. K.; Tiwari, A.; Argal, S.; Chhajlani, R. K.</p> <p>2014-09-01</p> <p>The linear <span class="hlt">Rayleigh</span> Taylor instability of two superposed compressible Newtonian fluids is discussed with the effect of surface tension which can play important roles in space plasma. As in both the superposed Newtonian fluids, the system is stable for potentially stable case and unstable for potentially unstable case in the present problem also. The equations of the problem are solved by normal mode method and a dispersion relation is obtained for such a system. The behaviour of growth rate is examined in the presence of surface tension and it is found that the surface tension has stabilizing influence on the <span class="hlt">Rayleigh</span> Taylor instability of two superposed compressible fluids. Numerical analysis is performed to show the effect of sound velocity and surface tension on the growth rate of <span class="hlt">Rayleigh</span> Taylor instability. It is found that both parameters have stabilizing influence on the growth rate of <span class="hlt">Rayleigh</span> Taylor instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25770095','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25770095"><span id="translatedtitle">Utilizing the Plateau-<span class="hlt">Rayleigh</span> Instability with Heat-Driven Nano-Biosensing Systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Dan-dan; Xu, Yu-mei; Ding, Xian-ting; Yang, Jian; Ma, Zhi-jun</p> <p>2015-08-01</p> <p>Plateau-<span class="hlt">Rayleigh</span> instability describes the infinite falling stream of fluid breaks into smaller droplets. With the development of nanotechnology, more and more attention is being drawn to Plateau-<span class="hlt">Rayleigh</span> instability. This surface tension-driven instability performs well in the preparation of the nanoparticles, especially in photonics applications, such as optical micro-resonators in nano-biosensing systems. In this article, we mainly adopt the thermal fluid coupling method. The effect of temperature field on instability is studied with the aid of numerical simulation. In addition, the radius of the inner fluid column, the thickness of the outer fluid, and the temperature gradient are also studied to explore how the factors influence the Plateau-<span class="hlt">Rayleigh</span> instability. The wavelength of the instability is characterized by droplet diameter, which is formed through the process caused by Plateau-<span class="hlt">Rayleigh</span> instability. PMID:25770095</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24079915','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24079915"><span id="translatedtitle">Experimental study of ultrasonic beam sectors for energy conversion into Lamb waves and <span class="hlt">Rayleigh</span> waves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Declercq, Nico Felicien</p> <p>2014-02-01</p> <p>When a bounded beam is incident on an immersed plate Lamb waves or <span class="hlt">Rayleigh</span> waves can be generated. Because the amplitude of a bounded beam is not constant along its wave front, a specific beam profile is formed that influences the local efficiency of energy conversion of incident sound into Lamb waves or <span class="hlt">Rayleigh</span> waves. Understanding this phenomenon is important for ultrasonic immersion experiments of objects because the quality of such experiments highly depends on the amount of energy transmitted into the object. This paper shows by means of experiments based on monochromatic Schlieren photography that the area within the bounded beam responsible for Lamb wave generation differs from that responsible for <span class="hlt">Rayleigh</span> wave generation. Furthermore it provides experimental verification of an earlier numerical study concerning <span class="hlt">Rayleigh</span> wave generation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RScI...87g5111L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RScI...87g5111L"><span id="translatedtitle">Accurate Young's modulus measurement based on <span class="hlt">Rayleigh</span> wave velocity and empirical Poisson's ratio</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Mingxia; Feng, Zhihua</p> <p>2016-07-01</p> <p>This paper presents a method for Young's modulus measurement based on <span class="hlt">Rayleigh</span> wave speed. The error in Poisson's ratio has weak influence on the measurement of Young's modulus based on <span class="hlt">Rayleigh</span> wave speed, and Poisson's ratio minimally varies in a certain material; thus, we can accurately estimate Young's modulus with surface wave speed and a rough Poisson's ratio. We numerically analysed three methods using <span class="hlt">Rayleigh</span>, longitudinal, and transversal wave speed, respectively, and the error in Poisson's ratio shows the least influence on the result in the method involving <span class="hlt">Rayleigh</span> wave speed. An experiment was performed and has proved the feasibility of this method. Device for speed measuring could be small, and no sample pretreatment is needed. Hence, developing a portable instrument based on this method is possible. This method makes a good compromise between usability and precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25959057','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25959057"><span id="translatedtitle">Effects of Estimators on Ultrasound Nakagami Imaging in Visualizing the Change in the Backscattered Statistics from a <span class="hlt">Rayleigh</span> Distribution to a Pre-<span class="hlt">Rayleigh</span> Distribution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tsui, Po-Hsiang; Wan, Yung-Liang; Tai, Dar-In; Shu, Yu-Chen</p> <p>2015-08-01</p> <p>Ultrasound Nakagami imaging has recently attracted interest as an imaging technique for analyzing envelope statistics. Because the presence of structures has a strong effect on estimation of the Nakagami parameter, previous studies have indicated that Nakagami imaging should be used specifically for characterization of soft tissues with fewer structures, such as liver tissues. Typically, changes in the properties of the liver parenchyma cause the backscattered statistics to transform from a <span class="hlt">Rayleigh</span> distribution to a pre-<span class="hlt">Rayleigh</span> distribution, and this transformation can be visualized using a Nakagami imaging technique. However, different estimators result in different estimated values; thus, the performance of a Nakagami image may depend on the type of estimator used. This study explored the effects of various estimators on ultrasound Nakagami imaging to describe the backscattered statistics as they change from a <span class="hlt">Rayleigh</span> distribution to a pre-<span class="hlt">Rayleigh</span> distribution. Simulations and clinical measurements involving patients with liver fibrosis (n = 85) yielded image data that were used to construct B-mode and conventional Nakagami images based on the moment estimator (denoted as mINV images) and maximum-likelihood estimator (denoted as mML images). In addition, novel window-modulated compounding Nakagami images based on the moment estimator (denoted as mWMC images) were also obtained. The means and standard deviations of the Nakagami parameters were examined as a function of the backscattered statistics. The experimental results indicate that the mINV, mML and mWMC images enabled quantitative visualization of the change in backscattered statistics from a <span class="hlt">Rayleigh</span> distribution to a pre-<span class="hlt">Rayleigh</span> distribution. Importantly, the mWMC image is superior to both mINV and mML images because it simultaneously realizes sensitive detection of the backscattered statistics and a reduction of estimation variance for image smoothness improvement. We therefore recommend using m</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACP....1311853D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACP....1311853D"><span id="translatedtitle">Midlatitude cirrus classification at Rome Tor Vergata through a multichannel Raman-Mie-<span class="hlt">Rayleigh</span> lidar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dionisi, D.; Keckhut, P.; Liberti, G. L.; Cardillo, F.; Congeduti, F.</p> <p>2013-12-01</p> <p>A methodology to identify and characterize cirrus clouds has been developed and applied to the multichannel-multiwavelength <span class="hlt">Rayleigh</span>-Mie-Raman (RMR) lidar in Rome Tor Vergata (RTV). A set of 167 cirrus cases, defined on the basis of quasi-stationary temporal period conditions, has been selected in a data set consisting of about 500 h of nighttime lidar sessions acquired between February 2007 and April 2010. The derived lidar parameters (effective height, geometrical and optical thickness and mean back-<span class="hlt">scattering</span> ratio) and the cirrus mid-height temperature (estimated from the radiosonde data of Pratica di Mare, WMO, World Meteorological Organization, site no. 16245) of this sample have been analyzed by the means of a clustering multivariate analysis. This approach identified four cirrus classes above the RTV site: two thin cirrus clusters in mid- and upper troposphere and two thick cirrus clusters in mid-upper troposphere. These results, which are very similar to those derived through the same approach at the lidar site of the Observatoire de Haute-Provence (OHP), allows characterization of cirrus clouds over the RTV site and attests to the robustness of such classification. To acquire some indications about the cirrus generation methods for the different classes, analyses of the extinction-to-backscatter ratio (lidar ratio, LReff, in terms of frequency distribution functions and dependencies on the mid-height cirrus temperature, have been performed. A preliminary study relating some meteorological parameters (e.g., relative humidity, wind components) to cirrus clusters has also been conducted. The RTV cirrus results, recomputed through the cirrus classification by Sassen and Cho (1992), show good agreement with other midlatitude lidar cirrus observations for the relative occurrence of subvisible (SVC), thin and opaque cirrus classes (10%, 49% and 41%, respectively). The overall mean value of cirrus optical depth is 0.37 ± 0.18, while most retrieved LReff values</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="https://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="https://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.osti.gov/nle"><img src="https://www.osti.gov/images/footerimages/NLElogo31.png" alt="National Library of Energy" height="31" width="79"></a> <a href="http://www.science.gov"><img src="https://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="https://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> </body> </html>