Showing papers on "Transverse plane published in 1983"

Means for localizing target coordinates in a body relative to a guidance system reference frame in any arbitrary plane as viewed by a tomographic image through the body

Abstract: A localizer system is described which enables determination of the coordinates of a target located inside the human body and visualized on a tomographic scan image for essentially any arbitrary scan plane through the body It involves a means of fixing a frame in a known relationship to the body and placing the localizer system in a fixed position relative to the frame There is an axial axis defined for the localizer, and there are both parallel and transverse (perpendicular) rod elements as well as diagonal rod elements on the localizer These appear as spot images on the scan plane image and are sufficient in number and location to enable accurate calculation of a target image on the scan and determination of the target coordinates in space relative to the localizer This applies to plane scan cuts which are substantially parallel or perpendicular to the localizer axis

A test for transverse motions of clusters of galaxies

Abstract: Although a static lens can produce no change in the brightness of an isotropic radiation field, a moving lens produces a characteristic two-sided brightness pattern that may be used to deduce the transverse velocity of the lens. The magnitude of the effect is proportional to both the transverse velocity and the strength of the lens. We suggest here that this effect provides a method for measuring the transverse velocities of clusters of galaxies; in this case the lens is gravitational and the radiation field is the isotropic microwave background. The predicted magnitude of this effect is at the present sensitivity limits of observation but is at least as large as the expected level of primordial background fluctuations.

Contact assembly including spring loaded cam follower overcenter means

Abstract: A so-called blow-off type current limiting circuit breaker is constructed with a contact pressure spring that also holds the contact arm in open contact position when the contacts are blown open by electrodynamic forces. A multi-section cam means transmits contact opening and closing forces produced by a spring powered overcenter toggle type operating mechanism to the movable contact arm. A follower on the latter is biased into engagement with the cam means by the contact pressure spring. The cam means is so constructed that during contact blow-off the movable contact arm requires relatively little motion to move overcenter in the opening direction. One section of the cam means is constructed so that when the contact arm moves overcenter in the opening direction during contact blowoff, speed of the contact arm is controlled to an extent that contact rebound does not become a problem. Another section of the cam means is constructed so that with the line of action of the contact pressure spring extending lengthwise of the contact arm, a strong component of force is developed transverse to the length of the contact arm to urge the contacts into butt-type engagement.

Line‐of‐sight propagation through atmospheric turbulence near the ground

Abstract: Line‐of‐sight measurements of the log‐amplitude and phase fluctuations of pure tones between 250 and 4000 Hz propagated over distances between 2 and 300 m in the turbulent atmosphere close to the ground are compared quantitatively with simple theory using simultaneously measured meteorological variables. The theory is based on the assumption of homogeneous and isotropic turbulence and approximates the availability of eddy sizes in the source region of turbulence by a Gaussian spectrum. In particular the transverse or mutual coherence function (the coherence in a plane perpendicular to the direction of propagation) and the coherence in the direction of propagation which we call the longitudinal coherence, are also calculated and compared with the measurements. When the measured mean square phase fluctuations are compared with the theory using the meteorological measurements, good agreement is obtained. However the measured mean square log‐amplitude fluctuations are in general substantially smaller than predicted and, in addition, show clear evidence of saturation. The distance to saturation is shown to correspond to the longitudinal coherence length. Because of this behavior of the amplitude fluctuations both the transverse and longitudinal coherences are essentially a function of the phase variance only.

Electrophoresis using alternating transverse electric fields

Abstract: Apparatus for and a method of electrophoretically separating particles by electric fields which are transverse to each other, which alternate between respective high and low intensities out of phase with each other at a frequency related to the mass of the particles and which move the particles in an overall direction transverse to the respective directions of the fields. For separating large macromolecules, at least one of the fields preferably has an intensity gradient in a direction transverse to its own. The new arrangement makes it possible to: (1) separate particles (molecules) larger in size than those able to be separated with previously known techniques, (2) carry out separation at higher speed and at better resolution than is possible with previously known techniques, and (3) concurrently separate particles which differ greatly in mass (molecular weight).

A thermal oscillating two‐stream instability

Abstract: A theory for the oscillating two‐stream instability, in which the Ohmic heating of the electrons constitutes the nonlinearity, is developed for an inhomogeneous and magnetized plasma Its possible role in explaining short‐scale, field‐aligned irregularities observed in ionospheric heating experiments is emphasized The theory predicts that the initial growth of such irregularities is centered around the level of upper hybrid resonance Furthermore, plane disturbances nearly parallel to the magnetic meridian plane have the largest growth rates Expressions for threshold, growth rate, and transverse scale of maximum growth are obtained Special attention is paid to the transport theory, since the physical picture depends heavily on the kind of electron collisions which dominate This is due to the velocity dependence of collison frequencies, which gives rise to the thermal forces

Reflection from a periodically perforated plane using a subsectional current approximation

Abstract: The scattering from a zero thickness plane having finite sheet resistance and perforated periodically with apertures is calculated for arbitrary plane wave illumination. The surface current density within the unit cell is approximated by a finite number of current elements having rooftop spatial dependence. The transverse electric field is expressed in terms of the current, and the electric field boundary condition is satisfied in an integral sense over the conductor, generating a finite dimension matrix equation whose solution is the current density. Since the conductor shape is defined through the locations of subsectional current elements, arbitrary shaped apertures can be handled. The reflection coefficient and current distribution are calculated for square apertures in both perfectly conducting and resistive sheets, and for cross-shaped apertures. Finite resistivity is shown to cause the magnitude of the transverse magnetic (TM) reflection coefficient to decrease more rapidly and its phase to decrease less rapidly, as the angle of incidence approaches glancing. Through detailed plots of the current density, the current crowding around the apertures is made clearly evident.

Three-dimensional tertiary motions in a plane shear layer

Abstract: The nonlinear evolution of instabilities of a plane-parallel shear flow with an inflection-point profile is studied. The particular example of the cubic-profile flow generated in an inclined layer heated from above and cooled from below is chosen because it exhibits supercritical bifurcations for secondary and tertiary flows. Since the limit of small Prandtl number is assumed, buoyancy effects caused by temperature perturbations are negligible. The analysis describes first the transition to transverse roll-like vortices which become unstable at slightly supercritical Grashof numbers to a vortex-pairing instability with alternating pairing in the spanwise direction. Three-dimensional finite-amplitude solutions for this tertiary mode of motion are computed and discussed. Finally the question of the stability of the tertiary flow is addressed.

Nonlinear Elastic Frame Analysis by Finite Element

Abstract: Plane and space frames are considered. The member end rotations relative to the chords of the deformed member are assumed to be small. Large translations and rotations of the chord are allowed The longitudinal and transverse displacements are respectively interpolated by linear and cubic functions. The axial strain due to the transverse displacement is averaged over the element length. The averaging is shown to reduce the strain energy and the element stiffness. Without it the element would generally be too stiff. The incremental stiffness matrices are derived in Lagrange coordinates for small rotations. Solution procedures based on a fixed coordinate system and a moving or updated coordinate system are presented. Numerical results indicated that the fixed coordinate procedure works well for small displacement problems. The updated procedure is necessary if large displacements are involved. Comparison of numerical results with those of other methods indicates that the methods presented are competitive.

Transverse gradient field coils for nuclear magnetic resonance imaging

Abstract: In the production of nuclear magnetic resonance images, it is necessary to provide various magnetic fields with specified orientations and configurations in particular relationships with respect to a cylindrical coil form on which the RF and gradient coils are generally disposed. In particular, it is necessary to produce so-called transverse gradient fields which are oriented transversely with respect to the cylindrical form. It is necessary to produce a component parallel to the axis of the cylinder, but which component varies linearly in intensity in the direction transverse to the axis. That is to say, it is desirable to produce a magnetic field component within the cylinder such that surfaces on which this component is constant are parallel and are generally oriented parallel to the axis of the cylinder. Furthermore, for the purpose of providing proper spatial definition and resolution, it is necessary that this transverse field exhibit a highly linear variation in intensity inside the cylinder. In a nuclear magnetic resonance imaging system, two such coil sets are required and are oriented at right angles to one another so as to generate x-axis and y-axis positioning information. The present invention describes coil winding patterns which are capable of producing such transverse gradient magnetic fields with an exceedingly high degree of linearity.

Piezoelectric pressure and/or temperature transducer

Abstract: In a piezoelectric transducer (10) an external element (12) of tubular form receives a pressure, notably a pressure to be measured, on its external face (16). It is cut in a quartz crystal in one piece with a plate (25) capable of vibrating under the action of an electric stress and extending in a plane parallel to the longitudinal direction of the tubular element inside the latter. Each of the longitudinal edges of the plate is connected by a transverse connecting element (30, 31) to the internal face (14) of the tubular element so as to transmit forces (F1 and F2) resulting from the application of the external pressure to the plate (25) in a direction substantially parallel to its plane and perpendicular to the axis of the tubular element (12).

Energy Expenditure in Curved Open Channels

Abstract: This paper describes linear partitioning of energy expenditure in curved open channels. An analytical method which predicts energy losses due to longitudinal resistance and transverse circulation is presented; predicted results are compared with measurements. The transverse energy loss is evaluated using the velocity field of transverse circulation which is implicitly dependent on the internal turbulent shear and boundary roughness; thus, direct evaluations of the shear and boundary losses are avoided. Transverse circulation is often referred to as secondary circulation as its velocity component is generally substantially lower than the longitudinal or primary velocity. Such is not the case for the energy expenditure. The loss due to transverse circulation may be of the same order of magnitude as the longitudinal loss at a higher depth to radius ratio or lower channel roughness, or both.

A mechanism for generation of short-period transverse motion from explosions

Abstract: A large amount of short-period three-component data from explosions and earthquakes are examined for sites covering source-receiver distances 100 m to 2000 km. In general, the spatial attenuation and spectral composition of the maximum amplitude of transverse motion from explosions are found to differ considerably from those of the other two orthogonal components. A mechanism for the generation of the maximum amplitude short-period transverse motion from explosions is proposed in terms of scattering by heterogeneities encountered by seismic waves as they propagate from the source to the receiver. The transverse component coming out of the source region is generally small and “grows” with distance due to progressively more scattering. We suggest that at short distances from explosions, there is first near-source scattering of P into mostly SV ( P → SV ). The SV is then additionally scattered by small heterogeneities perturbing a nearly plane-stratified medium. This results in transverse motion with small amplitudes but rich in high frequencies. As the source-to-receiver distance increases, continuous interaction among the three orthogonal components of ground motion (via SV → SH and increasingly important SH → SV ) results in increasingly isotropic polarization, i.e., equal amplitude and spectrum for shear phases such as Lg . The effect of the free surface, where observations are generally made, is shown to make the observed transverse component larger than the radial and vertical components alone. At several sites, the spectra of all components of Lg from an explosion appear to be significantly deficient in higher frequencies so as to be potentially useful for source discrimination. This we believe to be due to the dominant generation of explosion shear waves by near-source P → SV scattering (including “scattering” from horizontal layers) which is more efficient at low frequencies. If near-source scattering of P did not occur, then we would not expect the discriminant to work. We also present evidence that the transverse component of P arrivals is of higher frequency than the radial and vertical P , implying that the near-receiver scattering process responsible for transverse motion is more complete at high frequencies. In addition to the observed data, theoretical investigations of scattering appear to qualitatively support the proposed mechanism.

Method for measuring the transverse profile of the head of a rail of a railroad track

Abstract: A method for measuring the transverse profile of the head of a rail of a railroad track according to which a luminous trace (1) is projected onto the surface of the head of a rail, in a direction perpendicular to the longitudinal axis of said rail, this trace (1) having a particular point (3). The trace obtained is observed from two directions forming an angle (α) between them, located on either side of a longitudinal plane of the rail (2) and forming an angle with the plan of projection of the trace. This observation creates two partial reproductions (1'; 1") of this trace (1). Finally the two partial representations (1', 1") are angularly displaced by an angle corresponding to the angles from which the trace is observed and the images (3', 3") of the particular point (3) of the trace (1) are superimposed to obtain the representation of the transverse profile of the rail in its totality.

High-frequency scattering from the edges of impedance discontinuities on a flat plane

Abstract: A high-frequency solution is presented for the scattering of a plane wave at the edges of surface impedance discontinuities on a fiat ground plane. Arbitrary uniform isotropic boundary conditions and a direction of incidence perpendicular to the edges of the discontinuities are considered for both the transverse electric (TE) and transverse magnetic (TM) cases. An asymptotic approximation of the exact solution given by Maliuzhinets and a spectral extension of the geometrical theory of diffraction (GTD) are used. Uniform expressions for the scattered field received at a point on the surface are given, including surface wave contributions. Numerical results are shown and in some examples they are compared with those obtained from a moment method (MM) solution.

Thermal print apparatus using a thermal transfer ribbon such as a multi-colored one, and printing method

Abstract: In a thermal printer the transfer ribbon such as one having sets of transverse color stripes is guided over of a ribbon support which carries the heat applying print head. The ribbon support is movable relative to the paper by an eccentric to move the ribbon into and out of contact with the paper. A support beam and a guiding roller are provided immediately behind print area to guide the ribbon away from the paper path in an angle of more than 45 degrees. This assures a separation of the ribbon from the paper essentially normal to its surface, thus avoiding shear upon relative movement between paper and ribbon and negates the need for a relatively bulky ribbon carrier material. Color printing is performed by clamping paper and ribbon, applying heat, transferring color material, retracting the ribbon from the paper, advancing the ribbon to the next color area, printing again on the very same paper area as often as desired, repeating this as often as necessary and advancing the paper after finishing the present print line.

Precision lapping system

Abstract: Apparatus for precisely machining the surface of a workpiece comprises a rotating plate with a flat, horizontal abrasive-laden surface against which the workpiece surface is forced by gravity. The workpiece is carried on the free end of an arm pivotably supported remote from the end of the arm carrying the workpiece. Loading of the workpiece work surface can be varied by shifting weights along the length of the arm or transverse to the length of the arm. The workpiece itself can comprise a bar on which several magnetic transducing heads have been deposited. Machining the workpiece surface to a preferred position accurately defines a dimension of choice, such as the throat height of these transducers.

Nuclear magnetic resonance imaging with reduced sensitivity to motional effects

Abstract: The effects of motion in a given direction of particles being imaged in an NMR imaging system are substantially reduced by using gradients in the given direction produced by gradient pulse sequences which exhibit a zero value first moment relative to the point in time at which phase determination of the particles occurs. This point in time is generally taken at the time at which the longitudinal magnetization is translated to the transverse plane, as that is the phase reference for the NMR signals produced by the particles.

Transverse effects and self-pulsing in optical bistability

Abstract: We consider the problem of optical bistability in a unidirectional ring cavity with spherical mirrors, with an incident field corresponding to a TEM00 mode. In the framework of the one transverse mode model, we analyze the steady state (both in the absorptive and in the dispersive case), and its stability in the absorptive case. We find that when the radius of the cylindrical atomic sample is much larger than the beam waist, no instability arises in the positive slope parts of the steady state curve. This results suggests that in order to observe self-pulsing in absorptive optical bistability it is necessary to fulfil as closely as possible the plane wave condition.

A method of aligning particles in a moving fluid sample

Abstract: A method is provided for aligning particles in a fluid sample 26 which are moving in a direction through a flow cell 10. A sheath fluid 22 also flows through the flow cell 10 parallel to the direction of flow of the sample fluid 26. The flow rate of the sheath fluid 22 or the sample fluid 26 can be adjusted such that the particles are aligned substantially with their minimum cross-sectional area extended transverse to the direction of flow and with their maximum cross- sectional area extended substantially parallel to the width of flow cell 10 and with the centers of mass A, B, C of the particles of fluid sample lying substantially in one plane 120. With the centers of mass A, B, C of the particles of the fluid sample substantially in one plane 120, a microscope 30 can be focused on the one plane to view the particles. In addition, the microscope 30 can be focused on a plane 122 different from the one plane 120 in order to achieve optical separation of the particles.

Waves Guided by Conductive Strips Above a Periodically Perforated Ground Plane

Abstract: This paper considers the propagation of waves along an array of conductive strips situated above a periodically perforated conductive plane. Each conductor has zero thickness and finite sheet resistance, and the dielectric is homogeneous. The surface current density on the conductors is approximated by a finite number of current elements having rooftop spatial dependence. The transverse electric field is expressed in terms of the current, and the electric field boundary condition is satisfied in an integral sense over the conductors. This generates a matrix equation whose solution gives the dispersion curve relating the propagation constant to frequency, as well as the current distribution. The simulation results are used to obtain equivalent transmission-line parameters applicable to printed circuit boards found in high-performance computers. A characteristic impedance is defined and it is shown that, with proper interpretation, the uniform transmission-line equations for propagation constant and characteristic impedance apply to such computer packages. The coupling between adjacent strips is caculated, and the effect of finite resistivity discussed.

Geos 2 plasma drift velocity measurements associated with a storm time Pc5 pulsation

Abstract: The Geos 2 electron gun experiment has been used to obtain electric field data during the compressional Pc5 pulsation event of Day 300, 1979. The phase relationships between the electric field and magnetic field observations show that the oscillation in the meridian plane appears to be a transverse Alfven standing wave in the second harmonic, while the compressional oscillation is symmetrical about the equatorial plane. Computations of the fields of a guided poloidal wave fit the transverse oscillation well. The oscillation is not completeley explained by existing theories. A comprehensive model of the oscillation is presented.

Catamaran with hydrofoils

Abstract: The invention discloses a catamaran type boat having two similar boat demi-hulls which are spaced apart and which are substantially parallel, each demi-hull having a base line (BL). The boat further includes a superstructure connecting the two demi-hulls transversely; an open space in the form of a tunnel defined between the superstructure and the two demi-hulls; a longitudinal center of gravity position (LCG) for the boat; at least one trim hydrofoil having a chord line (CL) extending between its leading edge and trailing edge and being located in the stern region of the boat and extending at least partially across the tunnel; and an attachment element for attaching all hydrofoils to the demi-hulls substantially along a transverse plane (TP) which is substantially at right angle to the longitudinal vertical center plane of the boat, and having an angle of between 1° and 7° to the base line (BL) of the demi-hulls at the main foil, and with the hydrofoil chord lines (CL) being at an angle of between 0° and 6° to the transverse plane (TP).

Coke oven charging car

Abstract: A car for charging a coke oven battery with coal. This car carries a plurality of integral coal hoppers. A particular space frame construction is disclosed to support these hoppers, and because of this construction a significant savings in the weight of the car is realized. This space frame includes a pair of horizontally spaced lower front and rear parallel transverse beams and upper front and rear parallel transverse beams. Longitudinally extending beams connect both ends of the upper and lower front transverse beams with the corresponding rear transverse beams. The above described structure is mounted on four wheel housings by means of four truss structures. Two of these wheel housings are positioned slightly in front of the front transverse beams and two are mounted slightly behind the front transverse beams. Each of the front wheel housings is connected to the front transverse beams by means of one of the truss structures, and each of the rear wheel housings is connected to the rear transverse beams by one of the truss structures.