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At least 361 records · Page 20

Kinematic wave theory

Jacobian calculation in kinematic theory of wave propagation, using ray equation

Hayes, W. D.↗

Kinematic reversal schemes for the geomagnetic dipole.

Fluctuations in the distribution of cyclonic convective cells, in the earth's core, can reverse the sign of the geomagnetic field. Two kinematic reversal schemes are discussed. In the first scheme, a field maintained by cyclones concentrated at low latitude is reversed by a burst of cyclones at high latitude. Conversely, in the second scheme, a field maintained predominantly by cyclones in high latitudes is reversed by a fluctuation consisting of a burst of cyclonic convection at low latitude. The precise fluid motions which produce the geomagnetic field are not known. However, it appears that, whatever the details are, a fluctuation in the distribution of cyclonic cells over latitude can cause a geomagnetic reversal.

Levy, E. H.↗

A sample computation of kinematic properties from cloud motion vectors.

Distributions of relative vorticity and balanced height have been computed from the cloud velocities associated with the cloud structure of an extratropical cyclone over the continental United States during a three-day period in March 1970. Cloud motions are assigned either to a 'mid-level,' or to a 'high level.' Derived vorticity and balanced height are compared with concurrent National Meteorological Center (NMC) analyses and also with similar kinematic quantities obtained from rawins at three constant-pressure levels. The computations of relative vorticity using mid-level cloud motion vectors show encouraging results. Patterns of computed cyclonic vorticity are related to the development, location, and movement of the surface cyclone. The analyses suggest that the 'mid-level' corresponds best to the 700-mb level. The vorticity analysis from the 'high-level' motion vectors presented difficulties.

Viezee, W.↗

SPACEBAR: Kinematic design by computer graphics

The interactive graphics computer program SPACEBAR, conceived to reduce the time and complexity associated with the development of kinematic mechanisms on the design board, was described. This program allows the direct design and analysis of mechanisms right at the terminal screen. All input variables, including linkage geometry, stiffness, and applied loading conditions, can be fed into or changed at the terminal and may be displayed in three dimensions. All mechanism configurations can be cycled through their range of travel and viewed in their various geometric positions. Output data includes geometric positioning in orthogonal coordinates of each node point in the mechanism, velocity and acceleration of the node points, and internal loads and displacements of the node points and linkages. All analysis calculations take at most a few seconds to complete. Output data can be viewed at the scope and also printed at the discretion of the user.

Ricci, R. J.↗

Kinematic stability of roller pairs in free rolling contact

A set of generalized stability equations was developed for roller pairs in free rolling contact. A symmetric, dual contact model was used. Four possible external contact profiles that possess continuous contacting surfaces were studied. It was found that kinematic stability would be insured if the larger radius of transverse curvature, in absolute value, and the smaller rolling radius both exist on the roller that has the apex of its conical surface outboard of its main body. The stability criteria developed are considered to be useful for assessing axial restraint requirements for a variety of roller mechanisms and in the selection of roller contact geometry for traction drive devices.

Savage, M.↗

Kinematical constraints on the observation of slow monopoles at the top of the atmosphere

Relativistic kinematics of monopole production and propagation in earth's atmosphere and magnetic field have been examined in the light of the observation of a magnetic monopole by Price et al. It has been shown that the observed monopole cannot result from nuclear interactions in the atmosphere and that the extraterrestrial origin of this monopole is very unlikely.

Badhwar, G. D.↗

Kinematics and spectra of planetary nebulae with O VI-sequence nuclei

Spectral features of NGC 5189 and NGC 6905 are tabulated. Fabry-Perot profiles around H alpha and O III lambda 5007 of NGC 5189, NGC 6905, NGC 246, and NGC 1535, are illustrated. The latter planetary nebula is a non-O VI-sequence, comparison object of high excitation. The kinematics of the four planetary nebulae are simply analyzed. Discussion of these data is motivated by the possibility of collisional excitation by high-speed ejecta from broad-lined O VI-sequence nuclei, and by the opportunity to make a comparison with conditions in the supernova remnant or ring nebula, G2.4 + 1.4, which contains an O VI-sequence nucleus of Population I.

Johnson, H. M.↗