scispace - formally typeset
Search or ask a question

Showing papers on "Rotation published in 1977"


Journal ArticleDOI
TL;DR: In this paper, a new method of measuring inertial rotation is presented based on the use of a passive ring resonator as the rotation sensing element and an external laser for measuring the difference between the clockwise and counterclockwise lengths of the resonator.
Abstract: A new method of measuring inertial rotation is presented. It is based on the use of a passive ring resonator as the rotation sensing element and an external laser for measuring the difference between the clockwise and counterclockwise lengths of the resonator. Preliminary performance data is included.

247 citations


Book ChapterDOI
TL;DR: An analytical theory for the three axes of the triaxial rigid earth (the angular-momentum axis, the figure axis, and the rotational axis) is developed in this article.
Abstract: An analytical theory is developed for the three axes of the triaxial rigid earth (the angular-momentum axis, the figure axis, and the rotational axis) A theory on rigid earth rotation will be important to one on a nonrigid earth, since the latter gives only the ratios between the amplitudes of rigid nutation and those of nonrigid nutation The present theory is characterized by the use of Andoyer variables, Hori’s averaging method, and a moving reference plane A comparison with Woolard’s theory shows that 1) the maximum difference in nutation of the angular-momentum axis, calculated from the same constants as Woolard adopted, reaches 00017; 2) the maximum discrepancy in Oppolzer terms is 0V0012: and 3) the present theory has no secular term either in the first power of time in the obliquity referred to the fixed ecliptic or in the angle between the figure axis and the rotational axis; both these secular terms appeared in Woolard’s theory and have an effect on the establishment of a reference system Nutation amplitudes as large as OOOOl are calculated for all three axes Use is made of Brown’s theory of the moon as improved by Eckert and of numerical values recommended at the working meeting of the International Astronomical Union held in Washington in September 1974 Any future revision of the lunar theory will not alter the values of the amplitudes of the nutational terms derived here

216 citations



Patent
01 Apr 1977
TL;DR: In this paper, the satellite tracking apparatus for use on board ship as part of a maritime communications satellite terminal is disclosed, in which a directional antenna is adapted to be trained in the direction of the satellite so as to be in communication therewith.
Abstract: Satellite tracking apparatus for use on board ship as part of a maritime communications satellite terminal is disclosed. A directional antenna which is adapted to be trained in the direction of the satellite so as to be in communication therewith is mounted so as to be positioned about three axes, namely train, elevation, and cross-level axes. The mount also has a fourth axis which is parallel to or collinear with one of the other axes. This fourth axis may be a level axis which is movable with the antenna. A stable platform is movable with and rotatable about the level axis. Sensors on this platform provide outputs to servo controllers which rotate the antenna about the elevation and cross-level axes to maintain the platform stable. An azimuth sensor such as a gyro compass and sensors responsive to angular motion with respect to the train axis may also be mounted on the platform and provide outputs to a servo controller which controls the bearing or azimuth position of the antenna. An open loop control is provided for the level axis which establishes an equivalent angle between the stable platform and the true elevation line of sight (an angle equal to but opposite from the true elevation angle to the satellite). A mislevel is thereby created and sensed by the sensor for the elevation axis which provides an output that activates the elevation axis servo controller to reduce the mislevel to zero and null, thereby achieving the desired elevation of the antenna. The antenna is stabilized and decoupled from the motions (roll, pitch and yaw) of the ship and changes in the ship's heading, in that the sensors are mounted on the stable platform which moves with the antenna. The need for coordinate conversion computers responsive to sensors strapped down to the deck or other ship structure and for alignment of the antenna axes with the pitch or roll axis of the ship is also eliminated. The rotation of the antenna about its boresight axis is eliminated; thus avoiding misalignment between the polarization of the antenna and the satellite signals.

174 citations


01 Jan 1977
TL;DR: In this paper, the authors combined advances in the theory of rotation with traditional approaches to study the rotational evolution of the 33 known natural satellites and found that only the regular satellites and Iapetus, Hyperion, Triton and the moon are tidally evolved.
Abstract: Recent advances in the theory of rotation are combined with traditional approaches to study the rotational evolution of the 33 known natural satellites. A calculation similar to that reported by Burns and Safronov (1973) is applied to each satellite to obtain the characteristic time of decay of any wobble motion to smooth rotation about the principal axis of maximum moment of inertia. Stability criteria and capture probabilities are calculated for the 3/2 spin resonance. Results show that only the regular satellites and Iapetus, Hyperion, Triton, and the moon are tidally evolved. Of these, 13 have confirmed synchronous rotation periods; capture probabilities into the 3/2 resonance indicate that none of the remaining 10 should be captured in nonsynchronous, commensurate spin states. For the most part, the irregular satellites retain their original spins except for a relaxation to principal axis rotation. Tidal evolution of the obliquities of the satellites is evaluated in the framework of the generalization of Cassini's laws for the moon. Nearly resonant, forced librations in longitude of 4.8 and 0.5 deg are calculated on the basis of the observed shapes of Phobos and Deimos, respectively.

113 citations


Journal ArticleDOI
TL;DR: In this article, the problem of the splitting of nonradial modes of stellar oscillation owing to slow differential rotation is examined, and integral expressions for the frequency splitting are derived for the case of cylindrically symmetric rotation, and, for a particular rotation ''law,'' the results are applied to cooling white dwarfs and upper-main-sequence stars.
Abstract: The problem of the splitting of adiabatic nonradial modes of stellar oscillation owing to slow differential rotation is examined. Integral expressions for the frequency splitting are derived for the case of cylindrically symmetric rotation, and, for a particular rotation ''law,'' the results are applied to cooling white dwarfs and upper-main-sequence stars.

91 citations


Patent
02 Feb 1977
TL;DR: In this article, a cyclone converter consisting of three concentric rotating bodies, either on shafts or cylindrical rails or the like, is used to obtain and regulate energy from the air or sea and river currents.
Abstract: A system for obtaining and regulating energy from the air or sea and river currents includes a cyclone converter formed by three concentric rotating bodies, either on shafts or cylindrical rails or the like. Fixed rollers or other electromagnetic systems permit the rotation of the group around an imaginary or actual geometrical shaft. The outside body is self-orientating with its main components and deflectors on rotating components or a base sliding rail. The intermediate concentric body or turbine is formed by rings and vanes and a system of rollers or electro-magnetic supports which are inside or outside the turbine. The inside body or diffuser rotates concentrically in a reverse direction to the turbine and has vanes of opposite complementary angles.

90 citations


Patent
17 Oct 1977
TL;DR: In this article, a rotor drive assembly that is rotatably mounted to a stationary base for rotation along a predetermined axis is described. And a flexible umbilical cable segment is provided for establishing fluid communication with the blood processing chamber.
Abstract: A centrifugal blood processing system is disclosed having a rotor drive assembly that is rotatably mounted to a stationary base for rotation along a predetermined axis. A rotor assembly, which includes a blood processing chamber, is rotatably mounted with respect to the base for rotation about the axis. A flexible umbilical cable segment is provided for establishing fluid communication with the blood processing chamber. One end of the cable segment is fixed with respect to the base along the axis at one side of the rotor assembly while the other end of the cable segment is attached on the axis in rotationally locked engagement to the rotor assembly. Guide means are provided for causing the umbilical cable to rotate about the axis with the motor drive assembly. Means are provided for rotating the rotor assembly and the rotor drive assembly in the same direction with a speed ratio of 2:1 to prevent the umbilical cable from becoming completely twisted during rotation of the rotor.

89 citations




Patent
27 Jan 1977
TL;DR: A fastener tensioning method and apparatus for obtaining a desired degree of tension in a fastener is described in this article, which is based on the turn of the nut method.
Abstract: A fastener tensioning method and apparatus for obtaining a desired degree of tension in a fastener. The apparatus includes a means for applying rotation to a fastener, a means for measuring the torque applied by the means for rotating the fastener, a means for determining a rate of change of torque applied to the fastener with respect to the rotation applied to the fastener, a means for detecting when the rate of change of torque with respect to rotation becomes a constant, a means for accomplishing a desired amount of rotation of the fastener beyond the rotation required to achieve the constant rate of change of torque with respect to rotation, and a means for shutting off the means for applying rotation to the fastener in response to the total desired rotation being achieved. The embodiment herein described improves the well-known "turn of the nut" method for fastener tensioning by providing that method with a well determined starting point.


Patent
Kurt Franke1
21 Mar 1977
TL;DR: In this article, a plurality of x-ray sources are arranged at equal angles about a rotating frame, each source and detector arrangement may provide the desired number of measurements such as 240, so that the required angular movement for scanning is reduced by a factor corresponding to the number of sources.
Abstract: In an illustrated embodiment a plurality of x-ray sources are arranged at equal angles about a rotating frame. Each source and detector arrangement may provide the desired number of measurements such as 240, so that the required angular movement for scanning is reduced by a factor corresponding to the number of sources. In one embodiment with three sources and 240 detectors for each source, the desired number of measured values may be obtained by rotation through 120 degrees instead of 360 degrees. In another illustrative embodiment, the narrow beam from the x-ray source covers about 30 detectors, the beam and detectors being linearly scanned so as to generate about 240 measurements, there being three source-detector arrangements separated by 60 degrees, so that scanning is carried out by rotation through 60 degrees rather than 180 degrees.

Journal ArticleDOI
TL;DR: In this paper, a theoretical tool has been developed for predicting, in a nonempirical manner, effects of streamline curvature and coordinate-system rotation on turbulent boundary layers, and the model predicts the curved-wall and the rotating coordinate system laws of the wall.
Abstract: A theoretical tool has been developed for predicting, in a nonempirical manner, effects of streamline curvature and coordinate-system rotation on turbulent boundary layers. The second-order closure scheme developed by Wilcox and Traci has been generalized for curved streamline flow and for flow in a rotating coordinate system. A physically based straightforward argument shows that curvature/rotation primarily affects the turbulent mixing energy; the argument yields suitable curvature/rotation terms which are added to the mixing-energy equation. Singular-perturbation solutions valid in the wall layer of a curved-wall boundary layer and a fully developed rotating channel flow demonstrate that, with the curvature/rotation terms, the model predicts the curved-wall and the rotating coordinate system laws of the wall. Results of numerical computations of curved-wall boundary layers and of rotating channel flow show that curvature/rotation effects can be computed accurately with second-order closure.


Patent
22 Aug 1977
TL;DR: A furnace or space heater is operated by a small electric motor which rotates an elongated cylindrical drum on a vertical axis, within an elliptical casing at a clearance of about one eighth of an inch in the annular chamber formed there between as mentioned in this paper.
Abstract: A furnace or space heater is operable at low cost by a small electric motor which rotates an elongated cylindrical drum on a vertical axis, within an elongated cylindrical casing at a clearance of about one eighth of an inch in the annular chamber formed therebetween A supply of light lubricant normally occupies the lower portion of the annular chamber but rises to fill the chamber during rotation of the drum The casing is enclosed in a housing, having a fan chamber containing an electric motor and fan or blower The motor shaft may rotate both the fan and the drum

Journal ArticleDOI
TL;DR: In this paper, the eigenvalue problem and transverse response of a circular plate, that is free at the periphery and that slides freely along the axis of symmetry without bending rotation, are theoretically analyzed.
Abstract: The eigenvalue problem and transverse response of a circular plate, that is free at the periphery and that slides freely along the axis of symmetry without bending rotation, are theoretically analyzed. The occurance of eigenvalues in the boundary conditions is accounted for with an extended operator definition in the equation of transverse motion. The stability of these plates under concentrated loads moving at uniform speed is analyzed for (i) harmonic transverse loading and (ii) loading proportional to transverse displacement and velocity. The harmonic loading case leads to a classical, critical‐speed analysis. The proportional loading case represents the excitation of the plate by transverse position guides. The number, orientation, and mechanical properties of the guides determine the transverse stability of the plate‐guide dynamic system.


Patent
23 Mar 1977
TL;DR: In this article, a limited rotation motor has a stator and a rotor mounted for limited rotation relative to the stator, and a drive system produces drive flux which is conducted through magnetic circuits that extend across air gaps between the stators and rotor to drive the rotor.
Abstract: A limited rotation motor has a stator and a rotor mounted for limited rotation relative to the stator. The stator is constructed to conduct bias flux through magnetic circuits that extend across air gaps between the stator and the rotor and a drive system produces drive flux which is conducted through magnetic circuits that extend across air gaps between the stator and rotor to drive the rotor. The stability of radial rotor position in its support bearings is enhanced by an imbalance in the bias flux magnetic circuits which continually produces a resultant radial force on the rotor so that a well defined radial position of the rotor is maintained over the range of limited rotation that the rotor moves in response to the drive system.

Journal ArticleDOI
K. Shiroki1
TL;DR: In this article, Czochralski crystal growth simulation experiments were performed in warmed sugar solutions concerning crystal rotation rate influence and three types of temperature variations beneath the rotating disk were observed with the disk rotation rate change.

Patent
15 Aug 1977
TL;DR: In this paper, a unitary unitary control for traverse and rotation of the vanes is described, and the control assembly includes meshing bevel gears, one coupled to an actuating rod or wand and the other to the rotation rod.
Abstract: Vertical blinds having commonly housed and traversely movable controls for controlling the traverse and rotation of the vanes are disclosed. In a disclosed embodiment, the vanes are supported by carrier members, and a rotation rod extends through the carrier members. The carrier members are slideable along the rotation rod. A control assembly is mounted to slide along and also rotate the rotation rod. Sliding of the control assembly along the rotation rod slides the carrier members to thereby traverse the vanes, and actuation of the control assembly rotates the rotation rod and the vanes. The control assembly includes meshing bevel gears, one of which is coupled to an actuating rod or wand and the other to the rotation rod whereby rotation of the wand causes rotation of the vanes. The control assembly is slid by means of the wand which is universally connected to the control assembly. The wand is thus a unitary control for actuating both traverse and rotation of the vanes.


Patent
19 Jul 1977
TL;DR: In this article, a spreader bar is suspended within the frame and is isolated during helicopter pitch and roll, so that the load may be selectively oriented relative to a vertical axis.
Abstract: Apparatus for use in an aircraft, such as a helicopter, for controlling rotation of a load suspended from a cable and for permitting the cable to swing relative to the helicopter. A frame includes a first or upper assembly which is mounted on the helicopter for pivotal movement about a first pivot axis. The frame also includes a second or lower assembly connected to the upper assembly which is pivotal about a second pivot axis extending transversely to the first pivot axis. A spreader bar is suspended within the frame and is isolated during helicopter pitch and roll. Helicopter yaw imparts positioning of the spreader bar relative to a vertical axis so that the load may be selectively oriented.

Journal ArticleDOI
TL;DR: In this article, a sheet embedded in a matrix which undergoes rotational three-dimensional strain under constant volume conditions has been studied, and the analysis of the deformational behavior of competent sheets of rocks embedded in less competent ones.

Patent
30 Nov 1977
TL;DR: A peristaltic pump construction with a cylindrical recess has been proposed in this paper, where a body is provided with a generally cylinrical recess having eccentric roller means mounted in the recess for rotation about the axis of the latter, and a conduit circumposed about the roller means within the recess being collapsed by the roller, the conduit being relatively stiff and heavy walled.
Abstract: A peristaltic pump construction wherein a body is provided with a generally cylindrical recess having eccentric roller means mounted in the recess for rotation about the axis of the latter, and a conduit circumposed about the roller means within the recess being collapsed by the roller means upon rotation of the latter, the conduit means being relatively stiff and heavy walled, and a side member being engageable across the recess for forcibly engaging a conduit about the roller means laterally into the recess.

Patent
10 Aug 1977
TL;DR: In this article, a pressure roll assembly for applying pressure forces to sheet material articles being driven by a conveyor is described, and means for guiding the shaft for axial movement and for restraining movement of the shaft transverse to its axis are provided.
Abstract: A pressure roll assembly for applying pressure forces to sheet material articles being driven by a conveyor. A pressure roll is mounted for rotation about a central axis. A longitudinally extending leaf spring has a first portion which supports the pressure roll for rotation about its central axis, and a longitudinally spaced second portion which is fixedly connected with a support member so that the leaf spring supports the pressure roll in a cantilevered condition. An axially extending shaft is disposed normal to the longitudinal axis of the leaf spring and is fixed to the support member. Means are provided for guiding the shaft for axial movement and for restraining movement of the shaft transverse to its axis. Means are further provided for adjusting the axial position of the shaft for adjusting the pressure in the nip between the pressure roll and the conveyor surface.

Journal ArticleDOI
TL;DR: Experimental tests were performed, which confirm the mathematically presented hypothesis and also confirm the validity of the mathematical model of narrow beam rotation radiography presented by WELANDER (1974).
Abstract: The definition of the blurring of narrow beam rotation radiography is revived. The relative value of the blurring is considered to be the most reliable measurement. Calculations of the layer thickness should be based on the definition of the relative blurring. Experimental tests were performed, which confirm the mathematically presented hypothesis and also confirm the validity of the mathematical model of narrow beam rotation radiography presented by WELANDER (1974).

Journal ArticleDOI
TL;DR: This paper measured the rotation rate of short-lived solar filaments as a function of their latitude and found that the resulting rotation curve appears to be somewhat flatter than the corresponding curve for long-lived filaments.
Abstract: We have measured the rotation rate of short-lived solar filaments as a function of their latitude. The resulting rotation curve appears to be somewhat flatter than the corresponding curve for long-lived filaments.

Journal ArticleDOI
TL;DR: In this paper, the selection rules governing Raman spectra of asymmetric top molecules are presented in a concise, comprehensive and more useful form than hitherto, followed by a brief description of computer programs which accurately simulate such Raman vibration-rotation band contours and enable individual transitions to be assigned.
Abstract: This paper describes and illustrates the characteristic types of rotational fine structure found in vibrational Raman bands of asymmetric top molecules. The first section contains a brief summary of the relevant theory leading to a formulation of the selection rules governing Raman spectra of asymmetric tops. They are presented in a concise, comprehensive and more useful form than hitherto. This is followed by a brief description of computer programmes which accurately simulate such Raman vibration-rotation band contours and enable individual transitions to be assigned. The final section illustrates the different band structures which can occur, namely, A, Ba, Bb, and Bc types, with possible mixtures of these in molecules of low symmetry. Attention is drawn to how information on the derivatives of elements of the polarizability tensor with respect to particular normal coordinates can be extracted from such spectra. Examples are given for ethylene and trans-1,2-dideuteroethylene.

Journal ArticleDOI
TL;DR: In this paper, the magnetic flux rotating in step with a type II superconducting disc is measured with orthogonal pick up coils for various previous magnetic histories vs H 0 applied ⊥ to the axis of rotation.