Microscopic Determination of Surface Wave Velocities in Heat Treated Steels by Ultrasonic Reflectivity Measurement

Abstract Determination of shallow earthquake source mechanisms by inversion of long-period (150 to 300 sec) Rayleigh waves requires epicentral locations with greater accuracy than that provided by routine source locations of the National Earthquake Information Center (NEIC) and International Seismological Centre (ISC). The effects of epicentral mislocation on such inversions are examined using synthetic calculations as well as actual data for three large Mexican earthquakes. For Rayleigh waves of 150-sec period, an epicentral mislocation of 30 km introduces observed source spectra phase errors of 0.6 radian for stations at opposing azimuths along the source mislocation vector. This is larger than the 0.5-radian azimuthal variation of the phase spectra at the same period for a thrust fault with 15° dip and 24-km depth. The typical landward mislocation of routinely determined epicenters of shallow subduction zone earthquakes causes source moment tensor inversions of long-period Rayleigh waves to predict larger fault dip than indicated by teleseismic P-wave first-motion data. For dip-slip earthquakes, inversions of long-period Rayleigh waves that use an erroneous source location in the down-dip or along-strike directions of a nodal plane, overestimate the strike, dip, and slip of that nodal plane. Inversions of strike-slip earthquakes that utilize an erroneous location along the strike of a nodal plane overestimate the slip of that nodal plane, causing the second nodal plane to dip incorrectly in the direction opposite to the mislocation vector. The effects of epicentral mislocation for earthquakes with 45° dip-slip fault mechanisms are more severe than for events with other fault mechanisms. Existing earth model propagation corrections do not appear to be sufficiently accurate to routinely determine the optimal surface-wave source location without constraints from body-wave information, unless extensive direct path (R1) data are available or empirical path calibrations are performed. However, independent surface-wave and body-wave solutions can be remarkably consistent when the effects of epicentral mislocation are accounted for. This will allow simultaneous unconstrained body-wave and surface-wave inversions to be performed despite the well known difficulties of extracting the complete moment tensor of shallow sources from fundamental modes.

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Experimental and Theoretical Determination of Electron Energy Distribution Functions in Surface Wave Plasmas

Microwave Discharges - NATO ASI Series ◽

10.1007/978-1-4899-1130-8_20 ◽

1993 ◽

pp. 303-312 ◽

Cited By ~ 2

Author(s):

U. Kortshagen

Keyword(s):

Surface Wave ◽

Energy Distribution ◽

Electron Energy ◽

Distribution Functions ◽

Electron Energy Distribution ◽

Theoretical Determination ◽

Energy Distribution Functions

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The Defect Structure of CdO

Zeitschrift für Naturforschung B ◽

10.1515/znb-1987-0617 ◽

1987 ◽

Vol 42 (6) ◽

pp. 746-749 ◽

Cited By ~ 6

Author(s):

Jenő Juhász ◽

Sarolta Igaz ◽

Béla Jóvér ◽

Zoltán G. Szabó

Keyword(s):

Solid Solution ◽

Chemical Analysis ◽

Defect Structure ◽

Direct Determination ◽

Good Reproducibility ◽

Heat Treated ◽

Defect Sites

Abstract Defect Sites of CdO, Reducibility, Analysis Three procedures of chemical analysis are proposed for the direct determination of excess Cd in CdO: a spectrophotometric, a titrimetric and a gravimetric one, for 0-1500 ppm, 500-50,000 ppm and above 5%, respectively. The good reproducibility and reliability is illustrated by results referring to CdO samples heat-treated in H 2 and in air between 100 and 350 °C. Reduction in H2 increases the concentration of excess Cd up to 4000 ppm, above that separate Cd phase forms. The excess Cd in solid solution (interstitial sites) is more resistant against re-oxidation, than the bulk Cd phase.

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Increasing contribution of grain boundary compliance to polycrystalline ice elasticity as temperature increases

Journal of Glaciology ◽

10.1017/jog.2018.56 ◽

2018 ◽

Vol 64 (246) ◽

pp. 669-674

Author(s):

COLIN M. SAYERS

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Orientation Distribution ◽

Resonant Ultrasound Spectroscopy ◽

Wave Velocities ◽

Polycrystalline Ice ◽

Resonant Ultrasound ◽

Increasing Temperature ◽

Shear Compliance

ABSTRACTMeasured elastic stiffnesses of ice polycrystals decrease with increasing temperature due to a decrease in grain boundary stiffness with increasing temperature. In this paper, we represent grain boundaries as imperfectly bonded interfaces, across which traction is continuous, but displacement may be discontinuous. We express the additional compliance due to grain boundaries in terms of a second-rank and a fourth-rank tensor, which quantify the effect on elastic wave velocities of the orientation distribution as well as the normal and shear compliances of the grain boundaries. Measurement of the elastic stiffnesses allows determination of the components of these tensors. Application of the method to resonant ultrasound spectroscopy measurements made on ice polycrystals enables determination of the ratio BN/BS of the normal to shear compliance of the grain boundaries, which are found to be more compliant in shear than in compression. The ratio BN/BS is small at low temperatures, but increases as temperature increases, implying that the normal compliance increases relative to the shear compliance as temperature increases.

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