scholarly journals Experimental demonstration of negative refraction with 3D locally resonant acoustic metafluids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benoit Tallon ◽  
Artem Kovalenko ◽  
Olivier Poncelet ◽  
Christophe Aristégui ◽  
Olivier Mondain-Monval ◽  
...  
Keyword(s):  
Experimental Data ◽  
Yield Stress ◽  
Multiple Scattering ◽  
Silicone Rubber ◽  
Acoustic Waves ◽  
Scattering Theory ◽  
Negative Refraction ◽  
Volume Fraction ◽  
Experimental Demonstration ◽  
Acoustic Beam

AbstractNegative refraction of acoustic waves is demonstrated through underwater experiments conducted at ultrasonic frequencies on a 3D locally resonant acoustic metafluid made of soft porous silicone-rubber micro-beads suspended in a yield-stress fluid. By measuring the refracted angle of the acoustic beam transmitted through this metafluid shaped as a prism, we determine the acoustic index to water according to Snell’s law. These experimental data are then compared with an excellent agreement to calculations performed in the framework of Multiple Scattering Theory showing that the emergence of negative refraction depends on the volume fraction $$\Phi$$ Φ of the resonant micro-beads. For diluted metafluid ($$\Phi =3\%$$ Φ = 3 % ), only positive refraction occurs whereas negative refraction is demonstrated over a broad frequency band with concentrated metafluid ($$\Phi =17\%$$ Φ = 17 % ).

ELASTIC pd SCATTERING AT HIGH ENERGIES

1988 ◽  
Vol 03 (05) ◽  
pp. 1301-1319 ◽  
Author(s):  
V.M. BRAUN ◽  
L.G. DAKHNO ◽  
V.A. NIKONOV
Keyword(s):  
Experimental Data ◽  
Differential Cross Section ◽  
Multiple Scattering ◽  
Cross Section ◽  
Differential Cross ◽  
Scattering Theory ◽  
High Energy ◽  
Multiple Scattering Theory ◽  
High Energies

High energy differential pd cross section is calculated in the framework of the multiple scattering theory, inelastic correction included. Special attention is paid to the analysis of the calculation uncertainties. The results agree well with the experimental data obtained at ISR energies in the q2 range 0.06–1.05 (GeV/c) 2. The calculation accuracy is proved to be not worse than 10–20% at q2~0.2 (GeV/c) 2 and much better at small q2, namely, ~1% in the optical point. Prediction for the differential cross section at UNK energy E lab =3 TeV is given.

Effect of Nb content on the strength of Cu–Nb filamentary microcomposites

2000 ◽  
Vol 15 (9) ◽  
pp. 1889-1893 ◽  
Author(s):  
Sun Ig Hong
Keyword(s):  
Experimental Data ◽  
Yield Strength ◽  
Yield Stress ◽  
Plastic Flow ◽  
Volume Fraction ◽  
Strength Increase ◽  
Unit Cells ◽  
Nb Content ◽  
Good Agreement

The yield strength of Cu–Nb filamentary microcomposites was predicted as a function of Nb content by modifying the barrier strengthening model. To predict the variation of the yield strength with Nb content, the interfilamentary spacing was calculated as a function of Nb content on the basis of the assumption that Nb filaments are distributed regularly along the sides of triangular unit cells. The yield stress can be described as the sum of the substructural strengthening component and the filament boundary strengthening term. The good agreement between the prediction and the experimental data suggests that the strength increase in Cu–Nb filamentary microcomposites with increasing Nb content results mostly from increasing the volume fraction of Nb filaments, which act as barriers to plastic flow.

ELASTIC AND INELASTIC PROTON MULTIPLE SCATTERING ON 12C AND 16O NUCLEI

1991 ◽  
Vol 06 (09) ◽  
pp. 775-780 ◽  
Author(s):  
YU. A. BEREZHNOY ◽  
V.P. MIKHAILYUK ◽  
V.V. PILIPENKO
Keyword(s):  
Experimental Data ◽  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Single Particle ◽  
Scattering Theory ◽  
Cluster Model ◽  
Diffraction Scattering ◽  
Multiple Diffraction ◽  
Nucleon Density ◽  
Mev Protons

The elastic and inelastic scattering polarization observables of the 800 MeV protons on 12C and 16O nuclei are calculated on the basis of the multiple diffraction scattering theory. It was shown that the results of the calculations for elastic p-12C and p-16O scattering by the α-cluster model with dispersion are in a better agreement with the experimental data than those with the single-particle nucleon density.

DETERMINATION OF MULTILAYER RELAXATIONS OF THE Cu(210) STEPPED SURFACE BY CALCULATION OF LEED INTENSITIES

1999 ◽  
Vol 06 (05) ◽  
pp. 819-824 ◽  
Author(s):  
Y. P. GUO ◽  
K. C. TAN ◽  
A. T. S. WEE ◽  
C. H. A. HUAN
Keyword(s):  
Experimental Data ◽  
Surface Roughness ◽  
Multiple Scattering ◽  
Scattering Theory ◽  
Multiple Scattering Theory ◽  
R Factor ◽  
Stepped Surface

In this report, we investigate the surface multilayer relaxation of clean Cu(210) by the Barbieri/Van Hove symmetrized automated tensor LEED calculation, based upon the multiple scattering theory. We have examined the change of Pendry R factor as a function of the structural and nonstructural variables in the calculation. The results show that a Rp factor of 0.20 can be achieved when the top 10 interlayer spacings of clean Cu(210) were optimized to experimental data using a muffin-tin radius of 1.217 Å and a muffin-tin zero of 8 eV. The first three interlayer spacings are d12=0.761± 0.04 Å, d23=0.759± 0.04 Å and d34=0.862± 0.03 Å, respectively (versus the bulk value of 0.807 Å). It therefore appears that the Cu(210) surface contracts to some extent, decreasing the surface roughness. The strain-induced multilayer relaxation of Cu(210) surface is discussed.

GENERALIZED CHOU-YANG MODEL AND MESON-PROTON ELASTIC SCATTERING AT HIGH ENERGIES

1989 ◽  
Vol 04 (07) ◽  
pp. 1747-1754 ◽  
Author(s):  
MOHAMMAD SALEEM ◽  
FAZAL-E ALEEM ◽  
HARIS RASHID
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Elastic Scattering ◽  
Multiple Scattering ◽  
Scattering Theory ◽  
Anisotropic Scattering ◽  
Proton Form Factor ◽  
Recent Experimental Data ◽  
High Energies ◽  
Proton Elastic Scattering

The various characteristics of meson-proton elastic scattering at high energies are explained by using the generalized Chou-Yang model which takes into consideration the anisotropic scattering of objects constituting pions(kaons) and protons. A new parametrization of the proton form factor consistent with the recent experimental data is proposed. It is then shown that all the data for meson-proton elastic scattering at 200 and 250 GeV/c are in agreement with theoretical computations. The physical picture of generalized Chou-Yang model which is based on multiple scattering theory is given in detail.

Comparison of soot models for reacting sprays in diesel engine-like conditions

2021 ◽  
pp. 095440702110154
Author(s):  
Pavan Prakash Duvvuri ◽  
Rajesh Kumar Shrivastava ◽  
Sheshadri Sreedhara
Keyword(s):  
Experimental Data ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Modeling Framework ◽  
Aerosol Dynamics ◽  
Significant Difference ◽  
Polycyclic Aromatic ◽  
Order Of Magnitude ◽  
Detailed Kinetics ◽  
Soot Model

Stringent emission legislations and growing health concerns have contributed to the evolution of soot modeling in diesel engines from simple empirical relations to methods involving detailed kinetics and complex aerosol dynamics. In this paper, four different soot models have been evaluated for the high temperature, high pressure combusting dodecane spray cases of engine combustion network (ECN) spray A which mimics engine-relevant conditions. The soot models considered include an empirical, a multistep, a method of moments based, and a discrete sectional method soot model. Two experimental cases with ambient oxygen volume of 21% and 15% have been modeled. A good agreement between simulations and experiments for vapor penetration and heat release rate has been obtained. Quasi-steady soot volume fraction contours for the four soot models have been compared with experiments. Contours of the species and source terms involved in soot modeling have also been compared for a better understanding of soot processes. The empirical soot model results in higher magnitude and spread of soot due to a lack of modeling framework for oxidation through OH species. Among the four models studied, the multistep soot model has been observed to provide the most promising agreement with the experimental data in terms of distribution of soot and location of peak soot volume fraction. Due to a two-way coupling of soot models, the detailed models predict an upstream location for soot as compared to the multi-step soot model which is one way coupled. A significant difference (of an order of magnitude) in the concentration of PAH (polycyclic aromatic hydrocarbons) precursor between multistep and detailed soot models has been observed because of precursor consumption due to the coupling of detailed soot models with chemical kinetics. It is recommended that kinetic schemes, especially those concerning PAH, be validated with experimental data with a kinetics-coupled soot model.

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