Showing papers on "Rotation published in 1987"

Spatial input apparatus

Abstract: A three-dimensional spatial input apparatus including a series of coplanar, single axis accelerometers configured to provide information on translation along and rotation around a set of orthogonal axes. A preprocessing computer determines the acceleration values output by the accelerometers and converts these values into a series of acceleration, velocity and position values in relation to the axis system, with corrections based on a change in the influence of gravity on the device as it rotates. The values are transmitted to an object control computer which takes appropriate action, including moving a cursor, rotating a displayed object, and controlling remote devices. The spatial input apparatus can have an attached pointer and be used as a three-dimensional digitizer in conjunction with the object control computer.

Aperture synthesis observations of the circumnuclear ring in the Galactic center

Abstract: Aperture synthesis observations with the Hat Creek millimeter-wave interferometer have been used to study the circumnuclear neutral gas ring in the Galactic center at high spatial and spectral resolution. The resulting data demonstrate the existence of a highly inclined, thin, and clumpy ring or disk of molecular material centered on IRS 16 and the radio point source. The molecular gas is dynamically coupled to ionized gas in the central cavity. The dominant large-scale velocity pattern of most of the molecular gas in the inner 5 pc is rotation. The rotation appears to be perturbed by a large local velocity dispersion, by warping of the structure, and by at least one cloud probably located in the ring but not participating in the rotation.

Changes in the Earth's rotation and low-degree gravitational field induced by earthquakes

Abstract: Analytical formulas based on the normal-mode theory are used together with a spherically symmetric earth model and the centroid-moment tensor solutions for earthquake sources to compute the earthquake-induced changes in the earth's rotation and low-degree harmonics of the gravitational field for the period 1977-1985. Spectral and statistical analyses are conducted on these changes. It is found that the earthquake-induced changes are two orders of magnitude smaller than those observed; most of these changes show strong evidence of nonrandomness either in their polarity or in their directions.

Anatomical bone plate and/or transfixion plate

Abstract: A bone transfixion plate for transfixing an acetabulum fragment to the os ilium, by screw means, following pelvic osteotomies with rotation of the roof of the acetabulum, particularly in a human patient. The plate comprises: a proximal region for application to the os ilium which is at least generally adapted for close application to the region to which it is applied; a distal region for application to the acetabulum fragment which is at least generally adapted for close application to the region to which it is applied, these regions being disposed at a mutual angle in the ventrodorsal/mediolateral plane in the range 10°-50°, preferably about 30° (or, in a plate for a dog, the angle in the equivalent plane is 20°-70° and preferably 30°-60°); and for forming this angle a generally wedge-shaped transition zone between the two regions, the greater width of the transition zone being preferably at the ventral edge of the plate (or, in a plate for a dog, preferably at the dorsal edge). The plate is an element of a transfixion system which may include wire loops passed over two screws in the region of the foramen ischiadicum, and additional transfixion means to the os ischium and os pubis comprising one wire loop passed over two screws, one of which is affixed to the acetabulum fragment and the other of which is affixed to the os pubis.

The magnetic field of Uranus

Abstract: Aspherical harmonic model of the planetary magnetic field of Uranus is obtained from the Voyager 2 encounter observations using generalized inverse techniques which allow partial solutions to complex (underdetermined) problems. The Goddard Space Flight Center 'Q3' model is characterized by a large dipole tilt (58.6 deg) relative to the rotation axis, a dipole moment of 0.228 G R(Uranus radii cubed) and an unusually large quadrupole moment. Characteristics of this complex model magnetic field are illustrated using contour maps of the field on the planet's surface and discussed in the context of possible dynamo generation in the relatively poorly conducting 'ice' mantle.

Rotational dynamics of irregularly shaped natural satellites

Abstract: The rotational histories of irregularly shaped satellites are studied and are found to differ from the standard picture of tidal evolution of satellite rotations Prior to capture into the synchronous rotation resonance, a narrow attitude-unstable chaotic zone is entered and the satellite begins to tumble chaotically It is noted that enhanced dissipation of energy during the chaotic-tumbling phase may effect the orbital evolution The theory suggests that, eventually, the rotation stays close to one of the accessible attitude-stable islands long enough for the weak tidal torque to remove the satellite from the chaotic zone

Method and apparatus for utilizing an electro-optic detector in a microtomography system

Abstract: The present invention is an apparatus and a method for producing tomographic images of an object irradiated by a beam of collimated radiation transmitted in a plurality of rays through a set of coplanar sections of an object as viewed from a plurality of angles about a rotation axis. The apparatus includes an imaging electro-optic detector to record the transmitted radiation, wherein the electro-optic detector alters the image format, the format alteration being focused; means to determine and align the projected position of the rotation axis on the electro-optic detector: means to align the object with respect to the rotation axis; means to determine and assure spatial uniformity detector response; means to reduce signal dependent backgrounds; means to determine the projection coefficients from the transmitted radition with respect to one or more reference calibration exposures; and means to compute a reconstructed image of the object's attenuation coefficients.

The Origin of Rigidly Rotating Magnetic Field Patterns on the Sun

Abstract: Using analytical calculations and numerical simulations, it is shown that a meridional component of magnetic-flux transport will offset the shearing effect of differential rotation and give rise to rigidly rotating patterns of large-scale magnetic field The nonaxisymmetric field attains a striped polarity pattern which rotates rigidly like a barber pole while its individual small-scale flux elements rotate at the differential rate of the latitudes they are crossing On the sun, the meridional transport is provided by supergranular diffusion possibly assisted by a small poleward flow New sources of flux retard this process and exclude the rigid rotation from the sunspot belts until well into the declining phase of the sunspot cycle This mechanism accounts for a number of heretofore unexplained phenomena including the tendency for coronal holes to rotate rigidly during the declining phase of the sunspot cycle

Magnetic compass system for a vehicle

Abstract: A compass and method of operation are disclosed for finding the heading of a vehicle. The heading is found using a compass having a rotor with a compass magnet thereon and means on the rotor defining a reference line in known relation with the polar axis of the magnet. The angular displacement of the rotor is measured between alignment with the direction reference axis and alignment with the local magnetic field. A search coil is used to torque the rotor so that it reaches a reference position in which the reference line thereon is aligned with the direction reference axis. A reference position encoder generates a pulse when alignment is achieved. An angular displacement encoder produces a digital signal which changes with each predetermined increment of rotation of the rotor and which is indicative of the direction of rotation. A microcomputer processes the signals to provide a cumulative count of the increments of rotation. The microcomputer adds a stored magnetic variation value to the cumulative count to provide an indication of true heading. A direction display is adapted to exhibit one direction symbol of a set of symbols for different vehicle headings with each symbol corresponding to a different range of counts in the cumulative count. The microcomputer converts the cumulative count to a different direction value for each different range and the display is changed when there is a change of direction value. The microcomputer provides a logical hysteresis to prevent the display from flashing between different symbols when the cumulative count is at a marginal value of a given range. The microcomputer also provides a time damping of the display by imposing a time delay before changing the display from one symbol to another.

Waist elastic applicator for diaper or similar article

Abstract: The invention is an apparatus for applying a tensioned elastic ribbon or ribbons transversely of a moving web or material. It is particularly well adapted for applying elastic to the waist zones of disposable diapers moving continuously in an end-to-end assembly. The apparatus has a supporting frame with a shaft providing an axis of rotation for at least one rotatable radial arm. A polygonal head is mounted at the end of each arm. This has a number of peripheral edges with clamps or vacuum orifices for holding a tensioned strand or strands of elastic ribbon. A drive rotates the radial arms and a rotating mechanism moves the heads (360/n)° for each full rotation of the radial arms where n is equal to the number of peripheral faces on the head. An anvil acts against the head at the time of application of the tensioned elastic to the moving web. The web is passed between the head and the anvil along a path describing a chord or tangent of the circle of rotation of the radial arms.

Rotation, acceleration, and gravity sensors using quantum-mechanical matter-wave interferometry with neutral atoms and molecules

Abstract: The invention is a neutral atom (and/or molecule) matter-wave interferometer (and/or set of interferometers) that can be used as an inertial sensor with a sensitivity exceeding that of conventional mechanical sensors and multiple circuit optical interferometers (including ring lasers) by many powers of ten. An interferometer in which matter-wave propagation beam paths enclose a finite area will sense rotations via the Sagnac effect. One with the paths displaced from each other will sense acceleration plus gravity. The matter-wave energy and mass dependence of the phase shifts that are due to rotation and acceleration are different. Thus a pair of interferometers with different energies and/or masses can perform simultaneous independent measurements of rotation and acceleration. Interferometers with paths that follow a figure-eight pattern yield a gravitational gradiometer. Laser cooling and slowing of a beam of neutral atoms provides a low energy nearly monochromatic source. One form of the invention comprises a sequence of slits and/or diffraction gratings operation in high order. Gratings consist of slits in a solid material or near-resonant standing-wave laser beams. Path curvature due to acceleration and rotation is canceled by magnetic and/or electric field gradients that produce an effective levitation of slow atoms. A feedback system that maintains an interferometer phase null is employed with its error signal yielding the inertial effect signals. Magnetic fields are used for producing matter-wave phase shifts. One form of detector images the Moire pattern formed in the light emitted from the resonance fluorescence of a standing matter-wave fringe pattern and a standing-wave laser beam.

Depth and latitude dependence of solar rotation

Abstract: A 15-day time series of spatially resolved full-disk Doppler observations is used to measure the dependence of p-mode oscillation frequencies on the mode azimuthal order m. This dependence may be used to infer the depth and latitude variation of the solar rotation. The results are consistent with solar models that have approximately the surface latitudinal differential rotation within the convection zone, but no latitudinal differential rotation in the radiative interior. The data do not make it possible to distinguish between models for which the angular rotation rate within the convection zone is a function of latitude alone, and those for which it is constant on cylindrical surfaces. Weak evidence for a pole-equator asymmetry in the sound speed is found. 18 references.

Hammer assembly for a rotary material crusher

Abstract: A hammer assembly for attachment to a rotor of a rotary material crusher is disclosed. The hammer assembly includes a hammer member rigidly connected to the rotor and an extension of the hammer member having a longitudinal axis disposed parallel and spaced relative the axis of rotation of the rotor. The extension has a uniform transverse cross-sectional configuration along the length of the extension. A cap means is removably connected to the extension for crushing the material on rotation of the rotor, the cap defining an undercut portion which cooperates with the extension for locking the cap adjacent the hammer member.

Theory of Faraday rotation by dilute suspensions of small particles

Abstract: We consider Faraday rotation by a dilute suspension of small particles embedded in a host. Using the Maxwell‐Garnett approximation, we obtain an expression for the complex effective dielectric tensor of the composite in the low concentration limit. The Faraday coefficient becomes anomalously large near the surface plasmon frequency of the small particles. Numerical examples are given for the frequency‐dependent off‐diagonal part of the dielectric tensor and for the angle of rotation.

Biomechanical basis for elbow hinge-distractor design.

Abstract: Experimental studies of flexion-extension motion were carried out on five fresh elbow autopsy specimens to determine the average axis of rotation (AAR). The AAR is defined as the best fit single axis of rotation for the full range of flexion-extension. AAR was determined on all five elbows and found to approximate the center of the capitellum and trochlea. The motion of the elbows approximated a fixed axis, and the carrying angle defined in reference to humeral shaft and forearm axis decreased from 13 degrees to 22 degrees in extension to close to zero in full flexion. The average axis of rotation, with guidelines for its anatomic location, was used as the basis for the design and placement of a hinge-distractor in treating posttraumatic elbows with poor motion.

On the Maximum Mass of a Uniformly Rotating Neutron Star

Abstract: The effect of rapid uniform rotation on the upper mass limit for neutron stars is studied under the assumption that the equation of state is subject to only a minimal set of physical constraints. For given ranges of the energy condition, microstability constraint, and causality constraint, the maximum mass of a uniformly rotating neutron star is about 24-25 percent greater than the corresponding nonrotating maximum mass. The obtained value is compared with that of the maximum mass of uniformly rotating configurations associated with the stiffest of the equations of state proposed for actual neutron-star matter. Rotation increases the upper limit on baryon mass by only about 20 percent, while the limiting moment of inertia is about twice its value for the nonrotating case. Upper limits are also found for the frequency of rotation, the frequency of frame dragging, and the maximum polar and equatorial redshifts. Discarding the causality constraint would allow the upper mass limit to increase by a given value. 16 references.

Pattern rotation angle detecting system

Abstract: A pattern rotation angle detecting system in which the angle of rotation of a pattern is detected according to the image data obtained by binary-coding and spatially-dividing the image signal of the pattern. The system comprises an extracting circuit for extracting the area and the moment of inertia of the image of the pattern directly from the binary-coded image data; a memory for storing the image data; and a processing circuit for obtaining the center of gravity of the image of the pattern using the area and the moment of inertia, circularly scanning the memory in such a manner that a circle is described having a center at the center of gravity, extracting arcuate segments, selecting as a reference arcuate segment one of the arcuate segments which satisfies predetermined conditions, mating a sample under detection with a standard sample using the properties of the reference arcuate segment and at least one arcuate segment from each side of the reference segments, and detecting the angle of rotation from the angle defined by the angle formed by a rotation angle reference point of the reference arcuate segment with respect to a predetermined reference line.

Spindle driver for machine tools

Abstract: A spindle driver for a machine tool which is adapted to move the spindle and a tool driven thereby in a helical path with variable pitch and with an orbital radius which may be varied. A quill (14) is mounted on a support member (12) and driven by a variable pitch drive mechanism in the form of a differential lead screw (26, 28) to provide a selectable ratio of axial motion to rotative motion of the quill. A spindle carrier (16) is rotatably mounted on the quill for rotation about an eccentric axis offset from the quill axis. A spindle motor (18) and a spindle driven thereby is mounted on a carrier with the spindle axis offset from the eccentric rotation axis. The orbital radius for the spindle is adjustable by rotation of the spindle carrier about the eccentric rotation axis to adjust the offset of the spindle axis.

A comparative study of rapidly and slowly rotating dynamical regimes in a terrestrial general circulation model

Abstract: As a preliminary step in the development of a general circulation model for general planetary use, a simplified vesion of thef GISS Model I GCM has been run at various rotation periods to investigate differences between the dynamical regimes of rapidly and slowly rotating planets. To isolate the dynamical processes, the hydrologic cycle is suppressed and the atmosphere is forced with perpetual annual mean solar heating. All other parameters except the rotation period remain fixed at their terrestrial values. Experiments were conducted for rotation periods of 2/3, 1, 2, 4, 8, 16, 64 and 256 days. The results are in qualitative agreement with similar experiments carried out previously with other GCMs and with certain aspects of one Venus GCM simulation. As rotation rate decreases, the energetics shifts from baroclinc to quasi-barotropic when the Rossby radius of deformation reaches planetary scale. The Hadley cell expands poleward and replaces eddies as the primary mode of large-scale heat transport. Associated with this is a poleward shift of the baroclinic zone and jet stream and a reduction of the equator-pole temperature contrast. Midlatitude jet strength peaks at 8 days period, as does the weak positive equatorial zonal wind which occurs at upper levels at all rotation periods. Eddy momentum transport switches from poleward to equatorward at the same period. Tropospheric mean static stability generally increases in the tropics and decreases in midlatitudes as rotation rate decreases, but the global mean static stability is independent of rotation rate. The peak in the eddy kinetic energy spectrum shifts toward lower wavenumbers, reaching wavenumber 1 at a period of 8 days. Implications of these results for the dynamics of Venus and Titan are discussed. Specifically, it is suggested that the extent of low-level convection determines whether the Gierasch mechanism contributes significantly to equatorial superrotation on these planets.

Insulation displacing barrel terminal

Abstract: A multiple piece terminal includes a first section which is stationary relative to the housing of the connector and rotatable sections which are rotatable relative to the first section. Each of the sections is comprised of a single thickness of metallic material wrapped into a substantially cylinderical configuration, where the rotatable sections are of a larger outer diameter than the first section such that the rotatable sections can engagingly overlie the first section. The first section is mounted to an insulative housing with a post section upstanding through the center of the first section. The post has at least one through opening which includes at least partially along its length, a frusto-conical section for wire section through the opening. The rotatable sections of the terminal has two wire receiving openings, each in communication with a wire-receiving slot around the circumference of the cylinder, with the two wire receiving openings being on opposed sides of the through opening on the post. Caps fit over the rotatable sections of the terminal, each cap has a shoulder which is engagable with a free end of a respective rotatable section of the terminal for rotation of the rotatable section of the terminal relative to the first section of the terminal. When wires are placed in through the caps and the caps are turned, the rotatable sections of the terminal are rotated and the wires are terminated in the wire-receiving slots.

A central black hole in M32

Abstract: Observations are presented of the stellar rotation and velocity dispersion in M32. The projected rotation curve has an unresolved cusp at the center, with an amplitude of at least 60 km/s. The stellar velocity dispersion is constant at 56 + or - 5 km/s to a radius of 20 arcsec; a central bump in the observed dispersion is an artifact due to the rotation. The form of the rotation is such that isophotes have constant angular rotation velocity. The three-dimensional rotation field is modeled and the internal mean rotation of the stars around the center of M32 must reach at least 90 km/s at a radius of 2 pc. Hydrostatic equilibrium then requires 3-10 x 10 to the 6th solar masses of dark mass within the central parsec of M32. The possibility that M32 is undergoing core collapse and that this dark mass consists of dark stellar remnants is discussed, but ultimately rejected because the time scale for core collapse of M32 should be 2000 Hubble times. A more likely explanation of this dark mass, especially because of the presence of an X-ray point source at the center of M32, is a massive black hole.

Method for continuous camlobe phasing

Abstract: A method of attaining a desired engine performance comprises the steps of changing the angular position of a variable camlobe (or cam) member relative to a fixed camlobe (or cam) member from a first angular position to a second angular position. In changing from the first to the second angular position, the variable camlobe (or cam) member moves in a predetermined direction relative to the direction of rotation of a camshaft. The predetermined direction and the magnitude of the angular movement of the variable camlobe (or cam) member is dependent at least in part upon at least one desired operating condition of the engine. The method further comprises changing the angular position of both camlobe (or cam) members relative to a reference point of a drive pulley. This change in the angular position of both of the camlobe (or cam) members relative to the reference point involves movement of the camlobes (or cams) in a direction relative to the direction of rotation of a camshaft. The direction and magnitude of this movement is based at least in part upon at least one desired operating condition of the engine.