Vertical Motion Of Particles Research Articles

Calculation of Beam Injection and Modes of Acceleration for the JINR Phasotron

The analysis of particle motion from the injection region up to the final radius of the JINR high current phasotron is given. The purpose of the investigation was the appreciation of the beam quality and intensity. Synchrotron and betatron radial and vertical particle motion as well as space charge repulsion were included into the computer code for beam investigation. As a result, the beam intensity earlier appreciation of 40-45 ? A was confirmed, magnetic field tolerances in the first phase oscillation region were obtained and the required time dependences of acceleration voltage amplitude were refined.

Triple-Doppler Observations of a Convective Storm

Abstract The advantages of three or more radars is illustrated in terms of extended areal coverage, error variance reduction and mitigation of poor sampling effects of divergence fields near the ground. Errors in the horizontal and vertical particle motion fields are illustrated for a three-, four- and five-radar network, and the importance of experimental design is illustrated. A variationally formulated multiple-Doppler radar analysis, which includes data from a surface network, and an illustrative analysis of storm data are presented.

Motion of a granular material in a tall vibrating system

The vertical motion of particles is considered for a tall vibrating system; a study is made of the effects of stress waves on the distance between the bottom of the vessel and the bottom of the bed.

Reply to 'A Comment on "The Early Structural Evolution and Anisotropy of the Oceanic Upper Mantle"'

Crampin emphasizes two important points: first, surface waves in an anisotropic media, will, in general, possess three dimensional particle motion; and second, a rigorous means of inverting data concerning anisotropy is needed. However, surface waves which have travelled oceanic paths tend to have predominantly Love-type or Rayleigh-type particle motion and clear cases of three-dimensional motion are difficult to find. This may be because the observing stations are located on continents rather than within the anisotropic region, or because transverse motion associated with a wave which is predominantly Rayleigh-type may be misinterpreted as a component of radial motion in a direction deviating slightly from the great circle path to the epicentre. For a few paths in the Pacific, I have observed vertical particle motion coupled to short-period (6-8 s) waves of predominantly Love type, similar to the observation in Eurasia reported by Crampin (1967), but the primary evidence for anisotropy comes from the azimuthal variation of velocity and the inconsistency of Love and Rayleigh velocities. Only if no isotropic structure can be found which fits both Love and Rayleigh wave dispersion simultaneously should an anisotropic structure be considered. My inversion of the data in terms of SV and SH velocities was intended primarily to indicate the degree to which the observations are inconsistent with isotropic structures and was obviously not intended to be a complete description of the 21 independent elastic constants. Before rigorously tackling the inverse problem, a solution is needed to the forward problem of surface wave propagation in a spherical, gravitating earth with a liquid layer. To the best of my knowledge, the general problem has been solved only for a solid, flat-layered earth (Crampin 1970). Perhaps the most fruitful approach to inversion will be some combination of Smith & Dahlen’s (1973) perturbation technique with the forward approacb used by Crampin.

Waves, weather, and ocean bottom microseisms

The latest model of the Lamont Geological Observatory Ocean Bottom Geophysical Station (OBS III), located approximately 200 km WNW of San Francisco at a depth of 3.9 km, has been in operation since May 1966. In addition to long- and short-period seismic data, this station provides data on water current direction and speed, water temperature, long- and short-period pressure variations, and horizontal and vertical accelerations at tidal periods. Twenty-three microseismic storms have been detected on the seismic and pressure sensors during the first eight months of operation (May-December 1966). The characteristics of two of these storms have been studied in detail, and the results have been compared with data from the Berkeley seismographs. Both peaks in microseismic activity appear to be related to specific weather systems, one local and one distant. Correlation between local water waves and microseismic amplitudes is observed in one case but not in the other. Particle motion amplitudes on the ocean bottom were 3 to 5 times larger than those at a near-land station (Berkeley) for the vertical component and 7 to 10 times larger for the horizontal component. Predominant periods (6 to 8 sec) were the same at both sites. Ratios of horizontal to vertical particle motion and pressure to vertical motion were measured for microseisms and compared with theoretical values for Rayleigh waves. The combination of these two ratios proves to be a very sensitive method of determining sediment properties. Coherence between pressure and vertical motion is consistently high. It is concluded that (1) the observed microseisms propagate primarily as Rayleigh waves of the fundamental mode, and (2) the thickness of the sediment layer is 0.65 km. The predominant direction of microseismic propagation during both storms was approximately perpendicular to the coastline. Study of the average phase relationship of pressure, vertical particle motion, and horizontal particle motion shows that the direction of propagation is from sea to land if fundamental mode Rayleigh waves are assumed. The microseismic energy flux was approximately 4 times larger in the oceanic structure than in the continental structure near Berkeley for both storms.

ATTENUATION OF SHEAR AND COMPRESSIONAL WAVES IN PIERRE SHALE

Attenuation measurements were made near Limon, Colorado, where the Pierre shale is unusually uniform from depths of less than 100 ft to approximately 4,000 ft. Particle velocity wave forms were measured at distances up to 750 ft from explosive and mechanical sources. Explosives gave a well‐defined compressional pulse which was observed along vertical and horizontal travel paths. A weight dropped on the bottom of a borehole gave a horizontally‐traveling shear wave with vertical particle motion. In each case, signals from three‐component clusters of geophones rigidly clamped in boreholes were amplified by a calibrated, wide‐band system and recorded oscillographically. The frequency content of each wave form was obtained by Fourier analysis, and attenuation as a function of frequency was computed from these spectra. For vertically‐traveling compressional waves, an average of 6 determinations over the frequency range of 50–450 cps gives α=0.12 f. For horizontally‐traveling shear waves with vertical motion in the frequency range 20–125 cps, the results are expressed by α=1.0 f. In each case attenuation is expressed in decibels per 1,000 ft of travel and f is frequency in cps. These measurements indicate, therefore, that the Pierre shale does not behave as a visco‐elastic material.

The vertical motion of particles through the regenerative beam extractor of a synchrocyclotron

In a regenerative beam extractor, the vertical motion of particles approaching the regenrator is shown to be correlated about the line Z ̇ = − 1 2 TZ ; this correlation permits efficient design of the magnetic channel.