Showing papers on "Transverse plane published in 1973"

Stability of a circular cylinder oscillating in uniform flow or in a wake

Abstract: The lift and drag forces were measured on both a single circular cylinder and tandem circular cylinders in uniform flow at Reynolds numbers from 40 to 104, to investigate the stability of an oscillating cylinder A cylinder (the downstream one in the tandem case) was made to oscillate in either the transverse or longitudinal direction (perpendicular or parallel to the stream) In the case of a single cylinder, its oscillation causes the so-called synchronization in a frequency range around the Strouhal frequency (transverse mode) or double the Strouhal frequency (longitudinal mode) The aerodynamic damping for transverse oscillation becomes negative in the synchronization range In the case of tandem cylinders, at low Reynolds numbers in the pure Karman range synchronization was observed to occur only when the downstream cylinder oscillated inside the vortex-formation region of the upstream one, and at high (low subcritical) Reynolds numbers synchronization occurred irrespective of the cylinder spacing in either oscillating mode In the tandem case, too, the transverse oscillation of the downstream cylinder becomes unstable in the range of synchronization

The effect of slip on the motion of a sphere close to a wall and of two adjacent spheres

Abstract: The motion of a sphere towards a plane or another sphere is opposed by the fluid between them with a force which is inversely proportional to the gap. In consequence, it is impossible for a constant force to produce contact in a finite time, unless the Stokes equations are modified. When the gap is of the same order as the mean free path of the air molecules, the Stokes theory for the motion of the air must be modified. The Maxwell slip flow approximation is used in this paper to show that, when the gap is small, the resisting force between the approaching surfaces becomes only logarithmically dependent on the gap, and contact can be achieved in a finite time. The difficulty in applying the Stokes theory to the problem of determining collision efficiencies for cloud droplets is thereby removed. The calculated values of the resistance to approach are used to determine the motion of a sphere falling towards a plane. If the motion is compared with the corresponding motion when no allowance is made for slip flow, the sphere without slip would still be at a distance of 1.3 times the mean free path from the plane, when the sphere with slip has made contact. Transverse motion must also be considered if the trajectory of a particle close to a collector is required. The forces and couples on the sphere in that situation have a logarithmic dependence on the gap without slip, but they tend to constant values when the effect of slip is included. Some calculations of collision efficiency of drops falling under gravity (Hocking and Jonas [1]) have been amended to include the effect of slip when the colliding drops are very close together, and show a significant increase in the collision efficiency.

Notched surgical pin and breaking tool therefor

Abstract: A surgical pin formed of rigid material for joining bone sections in an area of fracture. Following insertion of the pin into the bone sections, a breaking tool in the form of a handleequipped tube is fitted over the free end portion of the pin and the pin is then broken externally of the bone and along a transverse plane defined in part by any one of a series of notches formed in the pin. The notches of the series are angularly offset about the axis of the pin to provide an arrangement which facilitates breaking of the pin only at a selected notch.

Multiple scattering of channeling ions in crystals-II. Planar channeling

Abstract: Planar channeling is discussed. The Fokker-Planck kinetic equation is derived for charged particle scattering in planar channeling. The main factors that affect dechanneling are examined. Comparison of the obtained solutions with experimental data on dechanneling shows satisfactory agrceinent. The importance of nuclear scattering due to discreteness of the atomic plane is demonstrated. The depth-dependcncc of the flux peaking effect is investigated. Also, the dependence of a channeled ion profile on direction, energy, and temperature is studied. It is inferred that the approximation of monotonic gain of the transverse energy (that is commonly used in the interpretation of experiments and that docs not include the diffusion in the transverse energy space) proves to be unsatisfactory.

Transverse Spread and Longitudinal Dissociation in the Distal A-V Conducting System

Abstract: Isolated preparations of portions of the canine intraventricular conducting system were studied by microelectrode techniques in order to determine the nature of transverse spread and longitudinal dissociation of impulses in bundle branches and false tendons. Driving stimuli were delivered to an eccentric location on normal conducting tissue, and the arrival times of the propagating impulses were mapped along the length and width of the bundle branch, or along the false tendon ipsilateral and contralateral to the site of stimulation. The difference between the arrival times on the two sides was found to decrease progressively as a function of distance from the site of stimulation, the data suggesting that transverse spread of impulses involves propagation through transverse crossover points between the longitudinally oriented conducting elements. Impulses originating eccentrically became uniformly conducted across the transverse axis of bundle branches 8-15 mm from the level of the stimulating electrode, and of false tendons 2-4 mm from the stimulus site. True longitudinal dissociation, producing conduction maps different from those representing normal transverse propagation, was seen occasionally in tissue having longitudinally oriented strips of abnormal tissue. However, early premature stimulation commonly resulted in longitudinal temporal dissociation of the premature responses, possibly due to functional block in the transverse crossover fibers.

Turbulent correlation measurements in a two-stream mixing layer.

Abstract: Two point space-time measurements of the axial component of fluctuating velocity were made using linearized hot-wire anemometry. Space scales, convected frame correlations and time scales, and convection velocities in the shear layer were evaluated. Both filtered narrow and broad band convected frame autocorrelations were determined. Differences between axial broad band convection velocities and both mean turbulence and mean entrained fluid velocities were observed. Scaled broad band convection velocities for the mixing layer and simple round jets were found to collapse to a common curve. Axial narrow band convection velocities showed strong frequency and transverse position dependence.

Nonlinear transverse vibrations of beams with properties that vary along the length

Abstract: The method of multiple scales is used to analyze the nonlinear transverse vibrations of inhomogeneous beams including the effects of transverse shear and rotary inertia. First‐order uniform perturbation expansions are derived for the displacements, shear force, and frequency in terms of the ratios of maximum transverse displacement to cross‐sectional radius of gyration and cross‐sectional radius of gyration to wave length.

Origin of Offsets of the Mid-Atlantic Ridge in Fracture Zones

Abstract: The offsets of the axis of the Mid-Atlantic Ridge in equatorial fracture zones are characterized by the existence of transverse ridges running adjacent and parallel to the east-west trenches marking each of the fracture zones. These transverse ridges are made essentially of blocks of ultramafic rocks, probably emplaced at the offsets as a result of upward solid protrusion from the upper mantle into the east-west crustal fractures. The ultramafic blocks appear to be older than the adjacent sea floor, and to behave as nonspreading blocks plastered between spreading subplates; they may be coupled with a stagnant zone postulated to exist in the upper mantle beneath the spreading axis. A hypothesis is presented whereby ultramafic transverse protrusions are related to the formation of the offsets of the Mid-Atlantic Ridge and of the trenches associated with the offsets. During the early stages of development of the Atlantic Rift, the ultramafic blocks protruded from the upper mantle where the rift intersected p...

Quantized Longitudinal and Transverse Shifts Associated with Total Internal Reflection

Abstract: In additional measurements following their experimental demonstration of the now well-known longitudinal shift of a light beam undergoing total reflection, Goos and H\"anchen have observed that an incident beam of natural light is separated into two beams with polarizations normal and parallel to the incidence plane. Although an explanation of this filtering effect of orthogonal modes is easy in terms of either the Artmann or the Renard formulas of the Goos-H\"anchen shift, which are deduced from a stationary phase and an energy-conservation argument, respectively, it seems that this explation has not yet been produced. We describe here associated theoretical and experimental work showing that both the longitudinal Goos-H\"anchen shift and the new transverse shift are quantized, each having two eigenvalues and two eigenfunctions, which are the principal linear polarization states in the first case and the circularly polarized states in the second case. Thus the longitudinal and the transverse shifts should not be simultaneously observable. This can be justified in terms of the so-called tangential and sagittal focal lines produced by total reflection from a point source. Our theoretical reasoning is based on formal properties of Poynting's energy-flux vector. Our experiments consist of (1) a confirmation, with photographic recording, of the Goos-H\"anchen "polarization effect," (2) a similar demonstration of the filtering of the two circular polarization modes by observation of the transverse shift. In the latter case our apparatus is similar to the one we have used for demonstrating the transverse shift, but with the circular polarization analyzer placed after rather than before the totally reflecting prism. Our new measurements also comprise an improved evaluation of the transverse shift.

Field Tests of Transverse Mixing in Rivers

Abstract: Five tests were made on transverse mixing in rivers. The transverse turbulent diffusion coefficient, averaged over long flow distances, was as much as three times larger than the value for an equivalent straight rectangular flume. This increase is due to the additional mixing associated with the protective groins which were present and with the helical motion resulting from channel bends. Net transverse velocities exist in rivers and can cause the local rates of transverse spreading to be significantly different from the rate associated with the average diffusion coefficient. Recommendations are given for conditions to be met in order to obtain meaningful data from field tests on rates of transverse diffusion in rivers.

Mode selection in GaAs injection lasers resulting from fresnel reflection

Abstract: In several recent papers, attention has been given to the Fresnel reflectivity associated with cleaved facets of the laser. The small dimensions of the heterostructure waveguide give rise to a considerable angular spread in the energy incident on the facet. As a result, the mode reflectivity is not given simply by the Fresnel equation, which is only valid for an infinite plane wave. Rather, it is a properly weighted average over the plane-wave distribution of the mode. The differences in mode reflectivity with respect to TE and TM modes, as well as the variations with mode number, have been offered as a possible explanation for the predominant appearance of TE modes and preference for higher order modes in the large optical-cavity (LOC) geometry. However, the considerations to date have ignored the finite extent of the field in the junction plane. This situation is rectified in this paper. It is shown that the splitting in the mode reflectivity values between TE (electric field in the junction plane) and TM (electric field perpendicular to the junction plane) modes is reduced, and under certain conditions TM modes can be favored. In particular, it is shown that if a TE mode is oscillating, then there is a preference for a lowest order mode in the plane of the junction and a highest order mode in the transverse plane. Conversely, if for some reason a TM mode is oscillating, then the preference is for highest order modes in the plane of the junction and lowest order modes in the transverse plane.

Cross array ultrasonic transducer

Abstract: Apparatus for ultrasonic examination of objects, particularly in medical diagnostic examination, is comprised of a first phased array transducer capable of focusing the beam of pulses of ultrasonic energy in the longitudinal plane of the transducer positioned transverse to the longitudinal plane of the first transducer. The second transducer is capable of being focused in the same plane as the first transducer.

Transverse mode control in semiconductor lasers

Abstract: A general formula for the transverse fundamental mode of oscillation (FMO) in a semiconductor laser is found, taking account of the saturation effect. The formula is applied to two specific cases, and the oscillation condiditions are discussed in detail for typical geometries, including the mesa-stripe geometry.

Optical noncontacting surface sensor for measuring distance and angle of a test surface

Abstract: An optical sensor is described for providing an output responsive to the position and normality of a test surface with respect to a predetermined plane. A beam of radiant energy is focused by a lens onto the test surface, while being modulated along its optical axis by a first mirror oscillating at one frequency and being modulated transverse to its optical axis by a second mirror at a second frequency. The first harmonic of the frequency of the modulation of the first mirror is then monitored as to phase and amplitude by a single photodetector to provide a measure of the direction and distance of the test surface from the determined plane. The sum or difference harmonic of the radiant energy reflected from the test surface is also monitored as to phase and amplitude by the same photodetector to provide a measurement of the normality of the test surface with respect to the determined plane.

Optical scanning system

Abstract: A system using a scanning mirror for scanning the field of view of an optical objective. The scanning mirror is mounted for rotation about an axis transverse to the major plane of the mirror and for pivotal oscillation about an axis lying substantially within the major plane of the mirror. The combined effect of rotation and pivotal movement is to scan the field of view of an optical objective. The scanning angle and other significant characteristics of the scan pattern may be changed as desired by means external to the system, producing, for example, a rosette, spiral, or circular scanned pattern with or without dimensional changes in the total scanned field of view. Such a scanning system may be embodied in seeker systems used for the guidance of radiation-seeking missiles operating in single or multiple regions of the electromagnetic spectrum.

Three-Dimensional Finite Element Analyses of Dams

Abstract: Three-dimensional finite element analyses were performed for dams in valleys with valley wall slopes of 1:1, 3:1, and 6:1. The results were compared with the results of two-dimensional analyses to evaluate the accuracy of two-dimensional analyses. The conclusions were: (1) plane strain analyses of the maximum transverse section provide accurate results for dams in valleys with valley wall slopes 3:1 or flatter; (2) plane stress analyses of the maximum longitudinal section do not provide accurate results; and (3) plane strain analyses of the maximum longitudinal section provide fairly accurate results for all valley wall slopes.

The Dynamic Response of Columns Under Short Duration Axial Loads

Abstract: Coupled nonlinear equations of motion in the axial and transverse directions are derived for a column under dynamic end load. Material dissipation is included by employing a Kelvin model for the material behavior. The dynamic response of the column in the presence of small transverse perturbations is investigated for short duration of axial loads. For certain geometric configurations, the inclusion of axial inertia permits parametric resonance of transverse modes due to the transient axial motion after the load is removed. The parametric effects are studied in detail. It is found that the usual simplified theory which neglects axial inertia adequately describes the column response provided the material dissipation is sufficiently large and/or the duration of loading is sufficiently long. For given dissipation parametric excitation becomes important as the load duration decreases. It becomes the dominant effect for very short duration loads.

Effect of lateral leakage on neutron waves in polycrystalline media

Abstract: The reduced three-dimensional transport equation for neutron wave propagation is solved in the velocity-dependent case with a separable scattering kernel by the eigenfunction-expansion method. The full-and half-range orthogonalities for the eigenfunctions are derived. The former is applied to solve the transport equation in an infinite system. In the case of a discontinuous total cross section, the contribution from the two-dimensional continuum in the spectral plane is reduced to an integral along the branch cut by applying the analytical continuation of the dispersion function. The effects of transverse buckling on the discrete and pseudo modes are examined by numerical calculations of the solution for beryllium and graphite.

Human reactions to whole-body transverse angular vibrations compared to linear vertical vibrations.

Abstract: An electro hydraulic vibration device was used to study the effects of some forms of angular motion in the transverse mode and a combination of angular transverse and vertical motion, common in ground vehicles. Heart rate, tracking error, hip and shoulder acceleration, and subjective judgements of three subjects were recorded under different test conditions using three different seats. The excitation acceleration had a 0-25 and 0-50 g peak to peak linear component on the seat at frequencies of 1, 1-7, 2-5, and 40 Hz. Man is more affected and shows more degraded performance under the influence of transverse angular vibration than under vertical vibrations alone. Worst is a combination of transverse angular and vertical motion. Tractor seats good for vertical vibrations are not necessarily good for transverse vibrations

Spectral broadening of an acoustic pulse propagating through turbulence

Abstract: The following analysis develops the equation for the scattered acoustic power and spectral broadening of a plane acoustic pulse propagating through atmospheric turbulence that is moving with a uniform wind transverse to the beam. Assuming weak single scattering, the resulting propagation broadening is proportional to the wind velocity divided by the outer scale of turbulence and is independent of the strength of turbulence and total propagation range. Further, the broadening for a medium with variable outer scale and wind shear (e.g., a vertical propagation path) is determined primarily by the highest ratio of transverse wind to outer scale encountered by the pulse.

On the Maintenance of the Polar Front jet Stream.

Abstract: A calculation of the mean transverse circulation about the polar front jet stream is performed by using a diagnostic balance, ω-equation method. The results show a thermally-direct mean transverse circulation about the jet stream system for this case study. An examination of the kinetic energy balance of this jet stream reveals that the direct transverse circulation is probably strong enough to maintain the jet against frictional dissipation but not enough to provide large lateral export of energy. However, significant amounts of energy are transferred upward across the tropopause. Further considerations are employed to argue that the mean transverse circulation obtained here is compatible with the observed distributions of temperature and potential vorticity about the jet core.

Double-worm extruder housing

Abstract: A liner for a double-worm or double-screw extruder housing having a longitudinal passage having the configuration of a pair of parallel intersecting cylindrical bores having a common chord or secant plane is formed of a pair of mirror symmetrical parallel cylindrical segmental tubes joined along a common chord plane constituting a symmetry plane parallel to the segment axes. The tube segments are butt-welded together at this chord plane and are formed with outwardly open notches at this chord in which the tubes are further joined together by fillet welds, i.e. deposits of weldment (deposit welds). The notches of the segments are disposed opposite one another and are longitudinally spaced apart by distances approximately equal to their longitudinal widths. On opposite sides of the liner the notches are staggered, i.e. where a pair of notches are formed in one transverse plane on one side of the liner, the other side has unnotched abutting faces and vice versa.

Experimental Investigation of the Laminar Flow Along a Straight 135° Corner

Abstract: The results of measurements in laminar flow along a straight 135° corner are presented. Near to the inlet edge plane the flow has an appearance resembling that reported by Zamir and Young for a 90° corner in which the isovels in transverse planes are concave outwards near the bisecting line of the corner, but unlike the 90° corner flow this characteristic diminishes with distance downstream in the case examined here. The analytical solution by Carrier is found to be a good representation of the flow in the 135° corner.

Knitting machine needle holder

Abstract: A knitting machine needle assembly, and elements thereof, with first and second needle clamping members, one of said members being longitudinally grooved to accept a multiplicity of needles and the other of said members carrying a transverse protuberance to secure needles carried in the grooves of the other against movement out of the bight of the members, each of the needles including a groove of a shape to cooperate with said protuberance.

The dispersion of transverse zero sound in liquid helium 3

Abstract: The dispersion relation for transverse sound in a Fermi liquid has been derived for all omega tau ( omega is the sound frequency, tau is the quasi-particle relaxation time), and using this the shear wave properties of liquid 3He have been calculated. For omega tau >1) transverse zero sound should propagate if the liquid is pressurized. The nature and properties of this zero sound are discussed, and suggestions are offered as to how it could be studied experimentally.