Showing papers on "Rotation published in 1980"

Net tectonic rotation, apparent tectonic rotation, and the structural tilt correction in paleomagnetic studies

Abstract: The conventional tilt correction in paleomagnetic studies is intended to correct for bedding tilt. It is assumed that tilt took place about the line of strike of bedding. The basic assumption is incorrect where tectonic rotations have taken place about nonhorizontal, inclined axes. In such cases the conventional tilt correction produces declination anomalies in paleomagnetic vectors. These resemble the effects of tectonic rotation but are more aptly interpreted as apparent tectonic rotation. The challenge of paleomagnetic studies in orogenic zones is to distinguish between plate tectonic rotation, local structural rotation about vertical axes, and apparent tectonic rotation. Some criteria for recognizing apparent tectonic rotation are given, with examples. Methods for determining axes of net tectonic rotation and of relative tectonic rotation are developed by combining rotations. These have many potential applications to structural and tectonic analyses.

Steerable directional antenna

Abstract: A steerable directional antenna assembly steerable about two perpendicular axes is disclosed. It comprises a directional horn antenna rotatably mounted on a horseshoe gimbal to rotate about a first axis. A curved wave guide feed is connected at one end to the feed portion of the directional antenna. The wave guide feed is disposed such that its center of curvature is located on the first axis of rotation. The curved wave guide has a circumferential slot in its outer side, the slot communicating between the ambient atmosphere and the wave guide interior. The gimbal and directional antenna are rotatably connected to a pedestal which is enabled to rotate the gimbal and directional antenna about a second axis which is perpendicular to the first axis. The antenna assembly further comprises a coaxial feed line which passes through an opening in the pedestal and is fixed to the pedestal. The outer conductor of the coaxial feed line is stripped away from one end of the line to expose the center conductor. The center conductor terminates in an enlarged probe portion. The curved wave guide feed is disposed to receive the center conductor through the circumferential slot and the enlarged probe portion is located within the wave guide interior. A reflecting plate is also disposed within the wave guide interior at a predetermined distance from the enlarged probe portion. The reflecting plate is rotatably connected through the slot to the coaxial feed line. The reflecting plate cooperates with the wave guide and enlarged probe portion to couple RF energy between the coaxial feed line and the directional antenna. It forces RF energy to propagate between the probe and the feed portion of the directional antenna regardless of the position of the directional antenna in rotation about the first axis. When the antenna is caused to rotate about the first axis the curved wave guide feed moves relative to the center conductor and enlarged probe portion along the circumferential slot. When the directional antenna is caused to rotate about the second axis the reflecting plate rotates about the second axis to cause all the RF energy to propagate between the enlarged probe and the feed portion of the directional antenna.

Zonal and meridional circulation of the lower atmosphere of Venus determined by radio interferometry

Abstract: The results of the Pioneer Venus differential long-baseline interferometry experiment are presented. The velocity component of the Pioneer probes as they fell to the surface of Venus was calculated from the Doppler shift of the received signal, and the other two orthogonal components were determined by long-baseline interferometry. The ambient wind velocity was about 1 m/s or less near the surface of the planet and about 100 m/s at an altitude of about 65 km at all four probe locations. Strata of high wind shear were found at altitudes of 15, 45, and 60 km. The wind velocity was always directed within a few degrees of due west except at a few km above the surface. The dominant motion of the lower atmosphere seems to be a retrograde zonal rotation, and eddies appear to account for most of the instantaneous meridional velocity. The data suggest that, within the clouds, a thermally driven mean meridional circulation is superimposed upon the much more rapid zonal rotation.

Limitation of rotation sensing by scattering.

Abstract: There appear to be limitations in the operation of optical-fiber Sagnac gyro rotation sensors that have imposed a minimum measurable rotation rate that is much higher than that caused by quantum noise. We show that one source of limitation, namely, the superposition of a nonreciprocal pair of waves generated by backward scattering from the incident waves, can result in significant error but can be mitigated by appropriate system design and signal modulation.

Rotatory stability of the load-bearing ankle. An experimental study

Abstract: The range of rotation of the talus in the horizontal plane was studied in the cadaveric ankle under conditions which simulated normal load-bearing. In the unloaded state there was 25 degrees of rotation, approximately half of which resulted from movement of the inferior tibiofibular joint. Rotation was load-dependent in both the intact ankle and in the ankle rendered unstable by division of the ligaments. Experimental division of the ligaments increased the range of rotation. The malleoli were contact areas during flexion and extension but excision of their articular surfaces caused only a moderate increase in rotation. The factors which limit talar rotation in intact and injured ankles are discussed.

A new calculation on rotating protostar collapse

Abstract: We calculate the isothermal collapse of a rotating axisymmetric gas cloud. The cloud is slowly rotating (EPSILON rotation/E gravitation =0.08) so that the collapse is deep, severely testing the angular momentum advection. Special care is taken to improve local conservation of angular momentum, which is monitored by a mass versus specific angular momentum spectrum.

Motion of a sphere in the presence of a plane interface.Part 2. An exact solution in bipolar co-ordinates

Abstract: A general solution for Stokes’ equation in bipolar co-ordinates is derived, and then applied to the arbitrary motion of a sphere in the presence of a plane fluid/fluid interface. The drag force and hydrodynamic torque on the sphere are then calculated for four specific motions of the sphere; namely, translation perpendicular and parallel to the interface and rotation about an axis which is perpendicular and parallel, respectively, to the interface. The most significant result of the present work is the comparison between these numerically exact solutions and the approximate solutions from part 1. The latter can be generalized to a variety of particle shapes, and it is thus important to assess their accuracy for this case of spherical particles where an exact solution can be obtained. In addition to comparisons with the approximate solutions, we also examine the predicted changes in the velocity, pressure and vorticity fields due to the presence of the plane interface. One particularly interesting feature of the solutions is the fact that the direction of rotation of a freely suspended sphere moving parallel to the interface can either be the same as for a sphere rolling along the interface (as might be intuitively expected), or opposite depending upon the location of the sphere centre and the ratio of viscosities for the two fluids.

Shear instability of differential rotation in stars

Abstract: The two-dimensional (horizontal) shear instability of a differentially rotating star is examined. A solar-type rotation law is investigated. and it is found that for equatorial accelerations there is instability when there is a difference of 29% between the angular velocity of the equator and the poles.

Comments on Quantum Mechanical Interference Due to the Earth's Rotation

Abstract: We present an elementary derivation of the quantum-mechanical phase shift induced by the Earth's rotation.

Electronic wrist watch with computer

Abstract: PURPOSE:To improve the operability of a keyboard in an electronic wrist watch by providing a mechanism for selecting and detecting the magnetic memory content upon rotation of a magnetic memory and removing a function key, memory selecting key or the like from the keyboard CONSTITUTION:When a crown 3 is rotated in the direction as designated by an arrow, rotation is transmitted from a drum wheel 5 to a magnetic memory plate drive gear 6 Thus, a magnetic memory plate 1 is rotated to coincide with any positon At this time information is inputted from a magnetic program detector 7 That is, the content of a magnetic memory mark 9 as seen from a magnetic memory mark opening 10 is inputted from the magnetic program detector to a computing IC to thereby select a functional formula or call a memory Thus, a function key, memory selecting key or the like are removed from a keyboard to thereby improve the operability of the keyboard

Aperture Synthesis by Object Rotation in Coherent Imaging

Abstract: Doppler processing is an established method for obtaining spatial resolution of objects which exhibit radial motion relative to an observing sensor. When applied to rotating objects, Doppler processing yields resolution in cross-range along an axis normal to both object rotation and line-of-sight axes. In this case, the cross-range resolution performance is dictated by the angular interval over which the data are observed and processed. This paper treats a tomographic extension of Doppler processing in the case of a rotating object (or a rotating planar array of point scatterers). It uses a stationary, continuous-wave (CW) irradiating source and sensor, co-located in the plane being imaged. The processing of data from a rotating object is shown to be equivalent to synthesizing an aperture which is a segment of a circle, however, processing over large angular rotations requires a focusing correction. Angular rotations up to and including 2? radians are considered. For this latter condition the system simulates an annular aperture which encloses the object. With this technique, high resolution may be obtained in all directions in the object plane without the use of a wideband signal, and equal point-objects separated by a quarter wavelength may be resolved. The imaging process provides high resolution for sparse arrays of objects of similar strength which are small in comparison to a wavelength. The imaging capability in the case of dense object arrays or large objects is limited and has a restricted dynamic range.

The Equatorial Rotation Rate of the Supergranulation Cells

Abstract: The equatorial rotation rate of the supergranulation cells has been observed to be 14.72±0.07°/day. Velocity patterns observed at different times are cross-correlated to derive the rotation rate. The observed rate is 3% faster than recent observations of the surface rotation rate by Doppler shifts. The difference between the cell rate and surface rate is consistent with a model of the supergranular convection in which angular momentum per unit mass is conserved in the radial flow (Foukal, 1977).

Direct measurement of vorticity by optical probe

Abstract: An optical system for direct measurement of vorticity in a flowing fluid is disclosed. Spherical particles suspended in the flow rotate with an angular velocity that is accurately equal to half the local vorticity; thus, measurements of the rotation rates of such particles indicate the vorticity. The particles are transparent, and preferably are less than 50 μm diameter, and each contains embedded planar crystal mirrors. The particles are suspended in a refractive index matched liquid. Measurement of the particle rotation rate and thus the vorticity of the fluid is preferably accomplished by measuring the rotation rates of reflections of one or more light beams from the planar mirrors. The measurements may be carried out using any system of position sensitive optical detectors such as photo sensitive devices screened by suitable slits or photo diode arrays.

Acceleration, radiation and precession in SS 433

Abstract: Some theoretical problems posed by the observations of SS 433 are considered. The monoenergetic beams point toward a gas-dynamic acceleration process. In this model the collimation implies that the acceleration occurs in a region of slab symmetry, possibly the surface layers of an accretion disk. The 164 day rotation of the beam pattern may be explained as a precession period.

Analysis of the LMR spectra of methoxy, CH3O

Abstract: The rotation spectrum of the free methoxy radical (CH3O) has been measured at 18 discrete wavelengths between 0.25 and 0.65 mm by the laser magnetic resonance method. A least‐squares fit to the measured spectra yields precise values for the molecular parameters of the 2E ground state of CH3O.

Autorotation of an elliptic cylinder about an axis perpendicular to the flow

Abstract: Autorotation of an elliptic cylinder about an axis fixed perpendicular to a parallel flow is explained in this paper by means of numerical solutions of the Navier-Stokes equations. Potential-flow theory predicts, for constant angular velocity, half a period in which a torque supports rotation and half a period in which it opposes rotation, with vanishing torque in the average. This balance is disturbed by viscous-flow effects in such a way that, for a given angular velocity, vortex shedding either damps rotation or, under certain conditions, favours rotation. The proper interplay of those conditions, which include synchronization of vortex shedding and rate of rotation, results in auto-rotation. The numerical results for Re [les ] 400 are compared with experimental data for Re = 90000 from the literature. The agreement of the force coefficients and the large-scale flow patterns is surprisingly good.

The rotation of the sun - Observations at Stanford

Abstract: Daily observations of the photospheric rotation rate using the Doppler effect made at the Stanford Solar Observatory since May 1976 are analyzed. Results show that these observations show no daily or long period variations in the rotation rate that exceed the observational error of about one percent. The average rotation rate is the same as that of the sunspot and the large-scale magnetic field structures.

Fiber-Optic Rotation Sensors

Abstract: Possible approaches to the design of fiber optic inertial frame rotation sensors based on the Sagnac effect are reviewed under two general categories: (1) single frequency interferometers which generate a phase shift proportional to inertial rotation rate, and (2) dual frequency interferometers for which the beat frequency is proportional to rotation rate. The principal variations within the single frequency class involve the way in which the nonreciprocal phase bias is used and techniques for generating the nonreciprocal bias. Within the dual frequency class, the various approaches differ principally in the way in which the counter-circulating frequencies are established.

Ca2+ reversibly inhibits active rotation of chloroplasts in isolated cytoplasmic droplets ofChara

Abstract: The effects of Ca2+ and other cations on chloroplast rotation in isolated cytoplasmic droplets ofChara were investigated by iontophoretically injecting them. Chloroplast rotation stopped immediately after Ca2+ injection and recovered with time, suggesting the existence of a Ca2+-sequestering system in the cytoplasm. The Ca2+ concentration necessary for the stoppage was estimated to be >10−4M. Sr2+ had the same effect as Ca2+. Mn2+ and Cd2+ induced a gradual decrease in the rotation rate with low reversibility. K+ and Mg2+ had no effects. Ba2+ had effects sometimes similar to Ca2+ or Sr2+ and sometimes similar to Mn2+ or Cd2+. Reversible inhibition by Ca2+, together with its specificity, strongly supports the hypothesis that a transient increase in the Ca2+ concentration in the cytoplasm upon membrane excitation directly stops the cytoplasmic streaming inCharaceae internodes (Hayama et al. 1979).

Process for centrifugal separation and apparatus for carrying it out, applicable to a mixture of phases of any states

Abstract: The invention relates to a process for centrifugal separation and to an apparatus for carrying it out, applicable to a mixture of phases of any states, said apparatus comprising, disposed coaxially and moved in rotation in a fixed enclosure, a fan adapted to create a depression upstream, a rotary distributor converting the pressure drop resulting from the action of the fan on the upstream pressure into a speed of rotation of the mixture added in the same direction to the positive speed of rotation of said distributor, and a rotor comprising elements for guiding running streams, trap elements which imprison still layers and pick up heavy particles, elements for conducting these latter.

Laser heterodyne surface profiler

Abstract: Method and apparatus for testing the deviation of the face of an object from a flat smooth surface using a laser beam having two plane-polarized components, one of a frequency greater than the other to produce a difference frequency with a phase to be used as a reference. The beam also is split into its two components which are directed onto spaced apart points on the face of the object. The object is rotated on an axis coincident with one component as a reference. The other component follows a circular track on the face of the object as the object is rotated. The two components are recombined after reflection to produce a difference frequency having a phase that is shifted in an amount that is proportional to the difference in path length as compared to the reference phase to produce an electrical output signal proportional to the deviation of the height of the surface along the circular track. The output signal is generated by means of a phase detector that includes a first photodetector in the path of the recombined components and a second photodetector in the path of the reference phase. The output signal is dependent on the phase difference of the two photodetector signals. A polarizer, a quarter-wave plate and a half-wave plate are in series in the path of the reference phase. Rotation of the half-wave plate can be used for phase adjustment over a full 360° range for initial calibration of the apparatus.

Ceiling fan with illumination means

Abstract: A ceiling sweep fan includes a motor depending from a ceiling mount, the motor being supported for rotation on a vertical axis, a plurality of radially extending air impeller blades supported for rotation by the motor, means for providing illumination mounted in radial alignment with the motor, and a shallow bowl-shaped light transmission member covers the motor and the illumination means.

Search and warning light system

Abstract: A search and warning light system is disclosed, in its preferred forms, as including a light assembly having first and second lamp assemblies. The light assembly is mounted about a vertical axis for rotation in either a clockwise or counterclockwise direction and the lamp assemblies are mounted to the light assembly about a horizontal axis for rotation in either an upward or downward direction. A control module located in a remote location provides appropriate electrical input to the motors controlling the rotation of the light assembly and the lamp assemblies, and to the lightbulbs included within the lamp assemblies. The motor for rotating the light assembly is located exteriorly of the light assembly in a first embodiment and is located interiorly of the light assembly in a second embodiment. The lamp assemblies can be independently rotated by providing separate motors and drive mechanisms or can be rotated together by rotatably relating the lamp assemblies.