Academic literature on the topic 'Bulk motin scattering'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Bulk motin scattering.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Bulk motin scattering"
1
Torres, James R., Zachary N. Buck, Helmut Kaiser, Eugene Mamontov, Madhusudan Tyagi, Flemming Y. Hansen, Kenneth W. Herwig, Luke Daemen, Michelle K. Kidder, and Haskell Taub. "Study of the water dynamics near hydrophilic, nanostructured CuO surfaces by quasielastic and inelastic neutron scattering." AIP Advances 12, no. 6 (June 1, 2022): 065124. http://dx.doi.org/10.1063/5.0096948.
Full textAbstract:
We have used quasielastic and inelastic neutron scattering to investigate the structure, dynamics, and phase transitions of water interacting with superhydrophilic CuO surfaces that not only possess a strong affinity for water but also a “grass-like” topography that is rough on both micro- and nanoscales. Here, we report quasielastic neutron scattering (QENS) measurements on two samples differing in water content at five temperatures below 280 K. The QENS spectra show water undergoing two different types of diffusive motion near the CuO surfaces: a “slow” translational diffusion occurring on a nanosecond time scale and a faster rotational motion. Further from the surfaces, there is “fast” translational diffusion comparable in rate to that of bulk supercooled water and the rotational motion occurring in the interfacial water. Analysis of the QENS spectra supports wetting of water to the CuO blades as seen in electron microscopy images. In addition, we observe an anomalous temperature dependence of the QENS spectra on cooling from 270 to 230 K with features consistent with a liquid–liquid phase transition. We suggest that the solvent-like properties of the coexisting bulk-like water in our CuO samples are a significant factor in determining the temperature dependence of the interfacial water’s dynamics. Our results are compared with those obtained from two well-studied substrate classes: (1) silicas that contain ordered cylindrical nanopores but have weaker hydrophilicity and (2) nanoparticles of other transition-metal oxides, such as TiO2, which share the strong hydrophilicity of our samples but lack their porosity.
2
Colpi, Monica. "Multiple Compton scattering by thermal electrons in a spherical inflow - The effects of bulk motion." Astrophysical Journal 326 (March 1988): 223. http://dx.doi.org/10.1086/166083.
Full text
3
Dhakal, Sujata, Zehao Chen, Daniel Estrin, and Svetlana Morozova. "Spatially-Resolved Network Dynamics of Poly(vinyl alcohol) Gels Measured with Dynamic Small Angle Light Scattering." Gels 8, no. 7 (June 22, 2022): 394. http://dx.doi.org/10.3390/gels8070394.
Full textAbstract:
Hydrogels are cross-linked polymer networks swollen in water. The large solvent content enables hydrogels to have unique physical properties and allows them to be used in diverse applications such as tissue engineering, drug delivery, and absorbents. Gel properties are linked to internal dynamics. While bulk gel dynamics have been studied extensively, how gel networks respond locally to deformation has yet to be understood. Here, poly(vinyl alcohol) (PVA) gels have been stretched to study the effects of deformation on gel dynamics parallel and perpendicular to the stretching direction using dynamic small angle light scattering (DSALS). The implementation of DSALS is described and compared to traditional DLS for PVA gels with different crosslink densities, ranging from 0.75–2%. Despite the orders of magnitude difference in the scattering vector, q, range of the techniques, the dynamics match, and the apparent elastic diffusion coefficient, DA increases linearly with the crosslink density for unstretched gels at a constant 2 wt% concentration. We observe that the elastic motion depends on the direction of stretch, decreasing perpendicular to stretching and increasing at parallel direction. Using DSALS can therefore be an effective tool to evaluate local hydrogel response to deformation.
4
Kedem, Ofer, Bryan Lau, Mark A. Ratner, and Emily A. Weiss. "Light-responsive organic flashing electron ratchet." Proceedings of the National Academy of Sciences 114, no. 33 (July 31, 2017): 8698–703. http://dx.doi.org/10.1073/pnas.1705973114.
Full textAbstract:
Ratchets are nonequilibrium devices that produce directional motion of particles from nondirectional forces without using a bias, and are responsible for many types of biological transport, which occur with high yield despite strongly damped and noisy environments. Ratchets operate by breaking time-reversal and spatial symmetries in the direction of transport through application of a time-dependent potential with repeating, asymmetric features. This work demonstrates the ratcheting of electrons within a highly scattering organic bulk-heterojunction layer, and within a device architecture that enables the application of arbitrarily shaped oscillating electric potentials. Light is used to modulate the carrier density, which modifies the current with a nonmonotonic response predicted by theory. This system is driven with a single unbiased sine wave source, enabling the future use of natural oscillation sources such as electromagnetic radiation.
5
Gessner, Oliver, and Andrey F. Vilesov. "Imaging Quantum Vortices in Superfluid Helium Droplets." Annual Review of Physical Chemistry 70, no. 1 (June 14, 2019): 173–98. http://dx.doi.org/10.1146/annurev-physchem-042018-052744.
Full textAbstract:
Free superfluid helium droplets constitute a versatile medium for a diverse range of experiments in physics and chemistry that extend from studies of the fundamental laws of superfluid motion to the synthesis of novel nanomaterials. In particular, the emergence of quantum vortices in rotating helium droplets is one of the most dramatic hallmarks of superfluidity and gives detailed access to the wave function describing the quantum liquid. This review provides an introduction to quantum vorticity in helium droplets, followed by a historical account of experiments on vortex visualization in bulk superfluid helium and a more detailed discussion of recent advances in the study of the rotational motion of isolated, nano- to micrometer-scale superfluid helium droplets. Ultrafast X-ray and extreme ultraviolet scattering techniques enabled by X-ray free-electron lasers and high-order harmonic generation in particular have facilitated the in situ detection of droplet shapes and the imaging of vortex structures inside individual, isolated droplets. New applications of helium droplets ranging from studies of quantum phase separations to mechanisms of low-temperature aggregation are discussed.
6
Hirota, Yuki, Taiki Tominaga, Takashi Kawabata, Yukinobu Kawakita, and Yasumitsu Matsuo. "Hydrogen Dynamics in Hydrated Chitosan by Quasi-Elastic Neutron Scattering." Bioengineering 9, no. 10 (October 21, 2022): 599. http://dx.doi.org/10.3390/bioengineering9100599.
Full textAbstract:
Chitosan, an environmentally friendly and highly bio-producible material, is a potential proton-conducting electrolyte for use in fuel cells. Thus, to microscopically elucidate proton transport in hydrated chitosan, we employed the quasi-elastic neutron scattering (QENS) technique. QENS analysis showed that the hydration water, which was mobile even at 238 K, moved significantly more slowly than the bulk water, in addition to exhibiting jump diffusion. Furthermore, upon increasing the temperature from 238 to 283 K, the diffusion constant of water increased from 1.33 × 10−6 to 1.34 × 10−5 cm2/s. It was also found that a portion of the hydrogen atoms in chitosan undergo a jump-diffusion motion similar to that of the hydrogen present in water. Moreover, QENS analysis revealed that the activation energy for the jump-diffusion of hydrogen in chitosan and in the hydration water was 0.30 eV, which is close to the value of 0.38 eV obtained from the temperature-dependent proton conductivity results. Overall, it was deduced that a portion of the hydrogen atoms in chitosan dissociate and protonate the interacting hydration water, resulting in the chitosan exhibiting proton conductivity.
7
Schwartz, D. A., D. E. Harris, H. Landt, A. Siemiginowska, E. S. Perlman, C. C. Cheung, J. M. Gelbord, et al. "Detailed structure of the X-ray jet in 4C 19.44 (PKS1354+195)." Proceedings of the International Astronomical Union 2, S238 (August 2006): 443–44. http://dx.doi.org/10.1017/s1743921307005868.
Full textAbstract:
AbstractWe investigate the variations of the magnetic field, Doppler factor, and relativistic particle density along the jet of a quasar at z=0.72. We chose 4C 19.44 for this study because of its length and straight morphology. The 18 arcsec length of the jet provides many independent resolution elements in the Chandra X-ray image. The straightness suggests that geometry factors, although uncertain, are almost constant along the jet. We assume the X-ray emission is from inverse Compton scattering of the cosmic microwave background. With the aid of assumptions about jet alignment, equipartition between magnetic-field and relativistic-particle energy, and filling factors, we find that the jet is in bulk relativistic motion with a Doppler factor ≈ 6 at an angle no more than 10∘ to the line of sight over de-projected distances ≈ 150–600 kpc from the quasar, and with a magnetic field ≈10 μGauss.
8
Zdziarski, A. A. "Radiative Processes and Geometry of Spectral States of Black-hole Binaries." Symposium - International Astronomical Union 195 (2000): 153–70. http://dx.doi.org/10.1017/s0074180900162898.
Full textAbstract:
I review radiative processes responsible for X-ray emission in the hard (low) and soft (high) spectral states of black-hole binaries. The main process in the hard state appears to be thermal Comptonization (in a hot plasma) of blackbody photons emitted by a cold disk. This is supported by correlations between the spectral index, the strength of Compton reflection, and the peak frequencies in the power-density spectrum, as well as by the frequency-dependence of Fourier-resolved spectra. Spectral variability may then be driven by the variable truncation radius of the disk. The soft state appears to correspond to the smallest truncation radii. However, the lack of high-energy cutoffs observed in the soft state implies that its main radiative process is Compton scattering of disk photons by nonthermal electrons. The bulk-motion Comptonization model for the soft state is shown to be ruled out by the data.
9
Li, Yuqing, Zehua Han, Changli Ma, Liang Hong, Yanwei Ding, Ye Chen, Junpeng Zhao, et al. "Structure and dynamics of supercooled water in the hydration layer of poly(ethylene glycol)." Structural Dynamics 9, no. 5 (September 2022): 054901. http://dx.doi.org/10.1063/4.0000158.
Full textAbstract:
The statics and dynamics of supercooled water in the hydration layer of poly(ethylene glycol) (PEG) were studied by a combination of quasi-elastic neutron scattering (QENS) and molecular dynamics (MD) simulations. Two samples, that is, hydrogenated PEG/deuterated water (h-PEG/D2O) and fully deuterated PEG/hydrogenated water (d-PEG/H2O) with the same molar ratio of ethylene glycol (EG) monomer to water, 1:1, are compared. The QENS data of h-PEG/D2O show the dynamics of PEG, and that of d-PEG/H2O reveals the motion of water. The temperature-dependent elastic scattering intensity of both samples has shown transitions at supercooled temperature, and these transition temperatures depend on the energy resolution of the instruments. Therefore, neither one is a phase transition, but undergoes dynamic process. The dynamic of water can be described as an Arrhenius to super-Arrhenius transition, and it reveals the hydrogen bonding network relaxation of hydration water around PEG at supercooled temperature. Since the PEG-water hydrogen bond structural relaxation time from MD is in good agreement with the average relaxation time from QENS (d-PEG/H2O), MD may further reveal the atomic pictures of the supercooled hydration water. It shows that hydration water molecules form a series of pools around the hydrophilic oxygen atom of PEG. At supercooled temperature, they have a more bond ordered structure than bulk water, proceed a trapping sites diffusion on the PEG surface, and facilitate the structural relaxation of PEG backbone.
10
GHOSH, HIMADRI, SUDIP K. GARAIN, SANDIP K. CHAKRABARTI, and PHILIPPE LAURENT. "MONTE CARLO SIMULATIONS OF THE THERMAL COMPTONIZATION PROCESS IN A TWO-COMPONENT ACCRETION FLOW AROUND A BLACK HOLE IN THE PRESENCE OF AN OUTFLOW." International Journal of Modern Physics D 19, no. 05 (May 2010): 607–20. http://dx.doi.org/10.1142/s0218271810016555.
Full textAbstract:
A black hole accretion may have both the Keplerian and the sub-Keplerian component. In the so-called Chakrabarti–Titarchuk scenario, the Keplerian component supplies low-energy (soft) photons while the sub-Keplerian component supplies hot electrons which exchange their energy with the soft photons through Comptonization or inverse Comptonization processes. In the sub-Keplerian component, a shock is generally produced due to the centrifugal force. The postshock region is known as the CENtrifugal pressure–supported BOundary Layer (CENBOL). In this paper, we compute the effects of the thermal and the bulk motion Comptonization on the soft photons emitted from a Keplerian disk by the CENBOL, the preshock sub-Keplerian disk and the outflowing jet. We study the emerging spectrum when the converging inflow and the diverging outflow (generated from the CENBOL) are simultaneously present. From the strength of the shock, we calculate the percentage of matter being carried away by the outflow and determine how the emerging spectrum depends on the outflow rate. The preshock sub-Keplerian flow is also found to Comptonize the soft photons significantly. The interplay between the up-scattering and down-scattering effects determines the effective shape of the emerging spectrum. By simulating several cases with various inflow parameters, we conclude that whether the preshock flow, or the postshock CENBOL or the emerging jet is dominant in shaping the emerging spectrum depends strongly on the geometry of the flow and the strength of the shock in the sub-Keplerian flow.
Dissertations / Theses on the topic "Bulk motin scattering"
1
Cullen, Jason Graham. "Inverse compton scattering in high energy astrophysics." University of Sydney. Physics, 2001. http://hdl.handle.net/2123/849.
Full textAbstract:
This thesis investigates some aspects of the inverse Compton scattering process within various physical contexts in high energy astrophysics. Initially an introduction to the key results of Comptonization theory for the case of scattering in optically thick plasmas is given, using a diffusion approach, since these results are required for the interpreta- tion of Comptonized spectra. Since Comptonization in astrophysical systems is frequently treated using numerical techniques, an introduction to these is then presented. Such linear Monte Carlo photon transport codes are typically applied to scattering in plasmas without temperature and density gradients. Additionally, treating bulk motion can be difficult even for simple cases. It is demonstrated that these problems can be made tractable numerically with the use of algorithms associated with non-linear Monte Carlo codes. Such codes can already treat scattering within arbitrary velocity structures in a plasma, and an extension of the algo- rithm is proposed that enables the easy calculation of photon transport in plasmas with non-constant density as well as non-constant temperature and/or bulk motion. This algorithm and code has been developed to treat scattering in astrophysical situations where bulk motion, temperature gradients and density gradients are simultaneously present in a plasma. Both a semi-analytic approach and the numerical approach are then used to treat Comp- tonization problems of current interest. Firstly, the standard two-phase disk-corona model for the high-energy spectra of Active Galactic Nuclei is modified to include an an outflow or wind which may provide an additional source of disk cooling. Earlier slab disk-corona models predict a spectral index which is consistent with observations only if all the accretion power is dissipated in the corona. For the models investigated here, energy spectral indices that are consistent with observations can be obtained with less accretion power being dissipated in the corona, as a result of an outflow/wind. However, it is required that the wind extract large amounts of power from the disk, and it it yet to be seen if this is a plausible scenario.
Books on the topic "Bulk motin scattering"
1
Furst, Eric M., and Todd M. Squires. Light scattering microrheology. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199655205.003.0005.
Full textAbstract:
The fundamentals and best practices of passive microrheology using dynamic light scattering and diffusing wave spectroscopy are discussed. The principles of light scattering are introduced and applied in both the single and multiple scattering regimes, including derivations of the light and field autocorrelation functions. Applications to high-frequency microrheology and polymer dynamics are presented, including inertial corrections. Methods to treat gels and other non-ergodic samples, including multi-speckle and optical mixing designs are discussed. Dynamic light scattering (DLS) is a well established method for measuring the motion of colloids, proteins and macromolecules. Light scattering has several advantages for microrheology, especially given the availability of commercial instruments, the relatively large sample volumes that average over many probes, and the sensitivity of the measurement to small particle displacements, which can extend the range of length and timescales probed beyond those typically accessed by the methods of multiple particle tracking and bulk rheology.
2
Boothroyd, Andrew T. Principles of Neutron Scattering from Condensed Matter. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198862314.001.0001.
Full textAbstract:
The book contains a comprehensive account of the theory and application of neutron scattering for the study of the structure and dynamics of condensed matter. All the principal experimental techniques available at national and international neutron scattering facilities are covered. The formal theory is presented, and used to show how neutron scattering measurements give direct access to a variety of correlation and response functions which characterize the equilibrium properties of bulk matter. The determination of atomic arrangements and magnetic structures by neutron diffraction and neutron optical methods is described, including single-crystal and powder diffraction, diffuse scattering from disordered structures, total scattering, small-angle scattering, reflectometry, and imaging. The principles behind the main neutron spectroscopic techniques are explained, including continuous and time-of-flight inelastic scattering, quasielastic scattering, spin-echo spectroscopy, and Compton scattering. The scattering cross-sections for atomic vibrations in solids, diffusive motion in atomic and molecular fluids, and single-atom and cooperative magnetic excitations are calculated. A detailed account of neutron polarization analysis is given, together with examples of how polarized neutrons can be exploited to obtain information about structural and magnetic correlations which cannot be obtained by other methods. Alongside the theoretical aspects, the book also describes the essential practical information needed to perform experiments and to analyse and interpret the data. Exercises are included at the end of each chapter to consolidate and enhance understanding of the material, and a summary of relevant results from mathematics, quantum mechanics, and linear response theory, is given in the appendices.
Conference papers on the topic "Bulk motin scattering"
1
Muhlestein, Michael B., Benjamin M. Goldsberry, Caleb F. Sieck, and Michael R. Haberman. "Analytical and Numerical Investigation of Scattering From Bianisotropic Acoustic Media." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72672.
Full textAbstract:
Scattering from fluid domains with dissimilar material properties is of foundational importance to many application areas in acoustics and elastic wave propagation. For example, biomedical ultrasound and sonar both make use of acoustic field scattering for localization, imaging, and identification of objects. The theory of acoustic scattering from fluid and elastic materials is well established and has been validated with numerical and physical experiments. Recent work in acoustic and elastic meta-materials has shown that materials with subwavelength asymmetry have a macroscopic response characterized by a scalar bulk modulus, a tensorial mass density, and a vector that couples the pressure-strain relationship with the momentum density-particle velocity relationship. This type of constitutive behavior is the acoustic analogue of bianisotropy in electromagnetism and has come to be known as Willis coupling in acknowledgement of the first description of this material response by J.R. Willis [Willis, Wave Motion 3, pp. 111 (1981)]. We present a theoretical description of acoustic scattering of a plane wave incident upon a cylinder exhibiting weak Willis coupling using a perturbation approach. The scattered field depends upon the orientation of the Willis coupling vector and is therefore anisotropic despite the symmetry of the geometry. The analytical model is validated through comparison with a finite element-based numerical experiment where the bianisotropic material response is introduced using a weak formulation of the constitutive equations.
2
Amaratunga, Maduranga, Roar Nybø, and Rune W. Time. "PIV Analysis of Dynamic Velocity Profiles in Non-Newtonian Drilling Fluids Exposed to Oscillatory Motion." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77614.
Full textAbstract:
Drilling fluids experience a wide range of shear rates and oscillatory motion while circulating through the well and also during the operations for solids control. Therefore, it is important to investigate the influence of oscillatory fields on the velocity profiles, shear rate and resulting rheological condition of non-Newtonian polymers, which are additives in drilling fluids. In this paper, we present the dynamic velocity profiles within both Newtonian (deionized water) and non-Newtonian liquids (Polyanionic Cellulose – PAC) exposed to oscillatory motion. A 15 cm × 15 cm square cross-sectional liquid column was oscillated horizontally with very low frequencies (0.75–1.75 Hz) using a laboratory made oscillating table. The dynamic velocity profiles at the bulk of the oscillating liquid column were visualized by the Particle Image Velocimetry (PIV) method, where the motion of fluid is optically visualized using light scattering “seeding” particles. Increased frequency of oscillations lead to different dynamic patterns and ranges of velocity-shear magnitudes. The experiments are part of a comprehensive study aimed at investigating the influence of low frequency oscillations on particle settling in non-Newtonian drilling fluids. It is discussed, how such motion imposed on polymeric liquids influences both flow dynamics as well as local settling velocities of cuttings particles.
3
Mermelstein, Marc D., and R. G. Priest. "Dynamic speckle spatial coherence measurements with single-mode optical fiber couplers." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.tui5.
Full textAbstract:
Recent experiments have demonstrated the suitability of single-mode optical fiber couplers in heterodyne laser light scattering experiments.1 The optical fiber coupler obviates the wavefront matching requirement at the photodetector in bulk optic arrangements and provides a moveable point-like optical probe of the scattered electric field. Three single-mode fiber optic couplers are utilized to measure the spatial coherence of the amplitude, phase rate, and amplitude weighted phase rate fluctuations of light scattered by polystyrene spheres suspended in water and undergoing Brownian motion. Light scattered with a wavevector k s is divided by a beam splitter and collected by two single mode fibers initially aligned with their cores superpositioned. One fiber is mounted on a piezoelectric translator so that the core spacing may be varied. The light collected by each fiber is combined with a local oscillator field, mixed at individual photodetectors, and subsequently demodulated. Coherence measurements for the two demodulated outputs are determined by a spectrum analyzer as a function of the core spacing. Amplitude coher ence measurements are in agreement with the Van Cittert—Zernike theorem for the transverse coherence length. Phase rate and amplitude weighted phase rate coherence measurements are also presented.