Propagation of a Shock Wave Front Through a Lens-Shaped Elastic Body

1974 ◽  
Vol 41 (3) ◽  
pp. 691-696 ◽  
Author(s):  
T. C. T. Ting ◽  
G. Herrmann
Keyword(s):  
Wave Front ◽  
Elastic Body ◽  
Cross Section ◽  
Pressure Pulse ◽  
Time History ◽  
P Wave ◽  
Back Surface ◽  
Ray Theory ◽  
S Wave ◽  
Discontinuous Pressure

Ray theory is used to solve the problem of a plane pressure pulse with a discontinuous pressure front striking an elastic body whose cross section has the shape of a lens. Both plane-strain and axisymmetric motions are considered. The front and back surfaces of the lens are assumed to be circular. The velocity and acceleration at the P-wave front and the discontinuity in acceleration at the S-wave front are obtained explicitly for points along the axis of the lens and at the center of the back surface where reflections occur. The purpose of this study is to assess the effect of the curvatures of the lens on the velocity-time history at the center of the back surface of the lens which can be measured experimentally. Comparison with a laboratory test shows excellent agreement between analytical and experimental results.

Wave-Front Analysis in Composite Materials

1969 ◽  
Vol 36 (3) ◽  
pp. 497-504 ◽  
Author(s):  
T. C. T. Ting ◽  
E. H. Lee
Keyword(s):  
Wave Front ◽  
Pressure Pulse ◽  
Spherical Inclusion ◽  
Stress Gradient ◽  
Back Surface ◽  
Ray Theory ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Linear Elastic ◽  
Elastic Composite

The propagation of an initially sharp plane pressure pulse through a linear elastic composite medium is analyzed. Wave front and ray theory analogous to geometrical optics is shown to determine the change in shape of the leading wave front and also the stresses immediately behind it. For certain circumstances the stress amplitudes on this front, or the corresponding tensile stresses on its reflection at the free back surface of a slab, may be critical in design. Examples are presented of an initially sharp plane pressure pulse transmitted through an elastic circular cylinder and an elastic spherical inclusion. The method can be applied to more general composite configurations, and can be extended to determine the stress gradient behind the front. For the latter, general formulas are derived by which the reflection and transmission coefficients can be determined for the stress gradient and the higher-order derivatives at an arbitrary interface.

scholarly journals Scattering Cross Sections in Argon from Electron Transport Parameters

1982 ◽  
Vol 35 (1) ◽  
pp. 35 ◽  
Author(s):  
GN Haddad ◽  
TF O'Malley
Keyword(s):  
Phase Shift ◽  
Cross Section ◽  
Cross Sections ◽  
Lateral Diffusion ◽  
Phase Shifts ◽  
P Wave ◽  
Transport Parameters ◽  
S Wave ◽  
Wave Phase ◽  
Range Theory

Previously determined experimental drift velocities Vdr and ratios of lateral diffusion coefficient to mobility DT/µ have been refitted directly with a three parameter modified effective range theory (MER T) representation of the S wave phase shift, a one parameter fit to the P wave phase shift and fixed higher partial wave phase shifts. The MERT representation now extends to 1·0 eV, a threefold extension of the energy range of the MERT fit reported by Milloy et al. (1977). The total cross section derived from the phase shifts is also reported, together with the differential cross section at 1·0 eV which is compared with a previous experimental determination.

scholarly journals keV Neutron Resonance Capture in Barium-137

1976 ◽  
Vol 29 (3) ◽  
pp. 157 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Allen ◽  
JW Boldeman ◽  
RL Macklin
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Strength Function ◽  
P Wave ◽  
Neutron Resonance ◽  
Resonance Capture ◽  
Level Spacing ◽  
S Wave ◽  
Radiative Width

The neutron capture cross section of 137Ba has been measured to high resolution (AE/E ~ o� 2 %) below En = 60 keY. Average values of resonance parameters, extracted for resonances in the range 2�7 < En < 12 keY, are as follows: s-wave level spacing <D) = 380� 70 eV; s-wave radiative width <Tv). = 80�15meV; s-wave neutron strength function 104 So = 0'57�0'2; and p-wave neutron strength function 104 S1 = 0�45�0�2. The s-wave radiative width and the s-wave neutron strength function appear to be lower for 137Ba than for the other barium isotopes.

scholarly journals Indirect detection of the partial p wave via the s wave in the annihilation cross section of dark matter

2019 ◽  
Vol 99 (8) ◽  
Author(s):  
Steven J. Clark ◽  
James B. Dent ◽  
Bhaskar Dutta ◽  
Louis E. Strigari
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Annihilation Cross Section ◽  
P Wave ◽  
Indirect Detection ◽  
S Wave

scholarly journals The Interaction of Neutrons with 7Be at BBN Temperatures: Lack of Standard Nuclear Solution to the “Primordial 7Li Problem”

2020 ◽  
Vol 227 ◽  
pp. 01007 ◽  
Author(s):  
M. Gai ◽  
E.E. Kading ◽  
M. Hass ◽  
K.M. Nollett ◽  
S.R. Stern ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Big Bang ◽  
Alpha Particles ◽  
P Wave ◽  
Recent Measurement ◽  
S Wave ◽  
Big Bang Nucleosynthesis ◽  
The Cross

We report the first measurement of alpha-particles from the interaction of neutrons with 7Be at “temperatures” of Big Bang Nucleosynthesis (BBN). We measured the Maxwellian averaged cross sections (MACS), with neutron beams produced by the LiLiT at the SARAF in Israel (with kT = 49.5 keV hence 0.57 GK). In addition, we measured the cross section of the 7Be(n,p) reaction, which is in excellent agreement with the recent measurement of the n_TOF collaboration, further substantiating our method as a demonstration of “proof of principle”. The cross section for the 7Be(n,ga) and the 7Be(n,a) reaction measured in the “BBN window” is considerably smaller than compiled by Wagoner in 1969 and used today in Big Bang Nucleosynthesis (BBN). We also rule out a hitherto unknown resonance in 8Be at the BBN window, that was conjectured as a possible standard nuclear physics solution to the “Primordial 7Li Problem”. Together with previous results, we deduce a new Wagoner-like Rate for the destruction of 7Be by neutrons which is based on all current measured data. We conclude the lack of a standard nuclear solution to the “Primordial 7Li Problem”. Our upper limit on the cross sections for the high energy alpha-particles is in agreement with recent measurement of the n_TOF collaboration, but it is considerably smaller than the p-wave extrapolation of the Kyoto collaboration. We measured the alpha-particles from the 7Be(n,gi)8Be*(3.03 MeV) reaction, which is considerably larger than a previous s-wave estimate. Hence, in contrast, we conclude s-wave dominance at BBN energies, as would be expected due to the broad (122 keV) low lying 2” state at En = 10 keV.

Propagation of a Shock Wave Front Across a Curved Fluid-Solid Interface

1976 ◽  
Vol 43 (4) ◽  
pp. 589-593 ◽  
Author(s):  
B. E. Bennett ◽  
G. Herrmann
Keyword(s):  
Shock Wave ◽  
Cross Section ◽  
Pressure Pulse ◽  
Center Line ◽  
Ray Theory ◽  
Reflection And Transmission ◽  
Solid Interface ◽  
Circular Arcs ◽  
Acoustic Fluid ◽  
Special Case

Geometric optics, or the ray theory, is used to investigate the effect of pulse reflection and transmission at a curved fluid-solid interface. In particular, the problem of a plane pressure pulse, supported by an acoustic fluid, impinging on a plane symmetrical elastic body whose cross section is delineated by circular arcs is considered. The response of the solid is determined along its center line to reflection at the back interface with another fluid. Consideration of the special case in which the fluid densities are zero indicates that special care must be exercised in dealing with the in vacuo problem, and particularly in specifying the boundary conditions in that instance.

scholarly journals ANALYSIS OF HIGH ENERGY K+K- PHOTOPRODUCTION ON HYDROGEN

2005 ◽  
Vol 20 (02n03) ◽  
pp. 581-583
Author(s):  
Ł. BIBRZYCKI ◽  
L. LEŚNIAK ◽  
A. P. SZCZEPANIAK
Keyword(s):  
Effective Mass ◽  
Cross Section ◽  
Good Description ◽  
Mass Range ◽  
High Energy ◽  
Mass Region ◽  
P Wave ◽  
S Wave ◽  
Mass Distributions ◽  
Scalar Resonances

We have analyzed the γp→pK+K- reaction in the K+K- effective mass region around the mass of the ϕ(1020) meson. The interference of the S-wave contribution with the P-wave has been studied. Both scalar resonances f0(980) and a0(980) have been taken into account. We obtained a good description of the available experimental data, in particular the mass distributions and the moments of the kaon angular distribution. Our calculations give values of the integrated S-wave total photoproduction cross section between 4 and 7 nb for the K+K- effective mass range around the ϕ(1020) mass and at the laboratory photon energy near 5 GeV. These numbers favor lower experimental estimates obtained at DESY.

THE CAPTURE OF PROTONS BY DEUTERONS

1962 ◽  
Vol 40 (4) ◽  
pp. 402-411 ◽  
Author(s):  
G. M. Griffiths ◽  
E. A. Larson ◽  
L. P. Robertson
Keyword(s):  
Angular Distribution ◽  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section ◽  
Gamma Rays ◽  
Proton Energy ◽  
P Wave ◽  
S Wave ◽  
Proton Capture ◽  
The Cross

The cross section and angular distribution of gamma rays for the reaction D(p,γ)He3 have been measured for proton energies from 275 kev to 1.75 Mev. For 275-kev protons the total cross section is 0.97 ± 0.11 microbarns and for 985-kev protons it is 3.5 ± 0.38 microbarns. The angular distribution has the form (sin2θ+b) where b is small. b is found to increase with decreasing proton energy, contrary to some previous results from this laboratory, and the energy dependence of b and of the cross section suggests that the sin2 θ part of the cross section is due to the capture of p-wave protons and the b part is due to s-wave proton capture.

scholarly journals Resonant Neutron Capture in 45Sc Below 100 keV

1977 ◽  
Vol 30 (6) ◽  
pp. 605 ◽  
Author(s):  
MJ Kenny ◽  
BJ Allen ◽  
RL Macklin
Keyword(s):  
Cross Section ◽  
Energy Resolution ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
P Wave ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
S Wave ◽  
Standard Deviations

The neutron capture cross section of 45SC has been measured with 0�2 % energy resolution in the range 2�S-100keV. Many new I> 0 resonances are observed and the average s- and p-wave radiative widths and standard deviations are <Γγ>s = 0�84�0�46eV and <Γγ>p = 0�S�0�3eV. No significant correlation is observed between the reduced neutron widths and radiative widths of the s-wave resonances.

A geophysical model for the Kapuskasing uplift from seismic and gravity studies

1991 ◽  
Vol 28 (3) ◽  
pp. 342-354 ◽  
Author(s):  
A. V. Boland ◽  
R. M. Ellis
Keyword(s):  
Cross Section ◽  
Wave Velocity ◽  
Poisson’S Ratio ◽  
Gravity Anomalies ◽  
P Wave ◽  
Poisson's Ratio ◽  
S Wave ◽  
Low Velocity ◽  
Cross Sectional ◽  
P Wave Velocity

The Kapuskasing uplift is an oblique cross section of Archean crust exposed by a major thrusting event in Early Proterozoic times. Previous results from the traveltime and amplitude analysis of compressional-wave (P-wave) arrivals from a seismic-refraction experiment have been used to constrain the modelling of shear-wave (S-wave) arrivals and gravity anomalies along the seismic profiles. S-wave and P-wave velocity information have been combined to obtain the variations of Poisson's ratio within the crust. High and low Poisson's ratio values have been linked to the mafic and felsic content, respectively, of the Shield rocks. Density variations along the profiles, constrained by the P-wave velocity structures and the observed gravity anomalies, again have been linked to the lithological variations as observed in the exposed cross section. Geological models, constrained by the geophysical observations and the cross-sectional exposure, have been constructed for profiles across the northern and southern portions of the main uplift region. The results indicate an increase in pyroxene and garnetiferous gneisses with depth in the crust, as suggested by the high P-wave velocities (7.0–7.6 km/s), high densities (3050–3150 kg/m3, high Poisson's ratio values (0.26–0.28), and the petrological variations within the exposure. The presence of a low-velocity and low-density layer of tonalites under the surface greenstones has been established and can account for the low-velocity zones imaged along the Abitibi profile of this experiment and those imaged in other Shield refraction experiments.

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