Showing papers on "Transverse plane published in 1981"

New effective field theory for the transverse Ising model

Abstract: A new type effective field approach is used to derive the thermodynamical properties of the transverse Ising model. The method is based on an exact formal identity for the two-state transverse Ising model and utilizes an exponential operator technique. The lines of critical points in the Ω-T plane are derived and the critical transverse fields ΩC are obtained analytically, for lattices with coordination numbers z = 2, 4 and 6. This simple method yields results which represent a remarkable improvement on the usual mean field approximation. Our results are also compared with those from series expansion method.

Compton scatter imaging of transverse sections: an overall appraisal and evaluation for radiotherapy planning

Abstract: A Compton scatter scanner has been developed to image electron density distributions of transverse body sections. The imaging performance of this device has been measured and compared with calculated limits and with the present capabilities of X-ray computed tomographic (CT) scanners. The use of Compton scatter images in radiotherapy dose calculations has been investigated and a calibration curve has also been measured from patient images to convert CT number data to electron densities for tissues in vivo. Images have been produced with a spatial resolution of 0.5 cm and an electron density accuracy of 4.3% for a radiation dose of 0.11 Gy (11 rad) to the patient. However, little potential remains for further development of the Compton scatter technique for whole-body imaging.

Postbuckling Analyses with Finite Strips

Abstract: The finite strip method of post-buckling analysis of prismatic plate structures subjected to axial compression is presented. The method is developed in two versions. The first one employs the classical approximations of junction conditions. The second ensures compatibility of displacements in the transverse plane at the junction. Examples are presented to illustrate the types of problems that each version can study most usefully.

Uniaxial type-II superconductors near the upper critical field

Abstract: The problem of a uniaxial type-II superconductor near the upper critical field is considered in the framework of the Ginzburg-Landau equations with a phenomenological mass tensor. The currents are shown to flow in planes which are in general no longer orthogonal to the direction of the vortex axes as in the isotropic case; the inclination angle is obtained in terms of anisotropic masses. The magnetic field has a component normal to the vortex axes; equations are derived which relate the transverse and axial fields. The average value of the transverse field (the transverse induction) vanishes. The constitutive relation between the induction and the magnetization is obtained. The components of the magnetization normal and parallel to the vortex direction are simply related in terms of the effective masses.

Heat exchanger accessory for electronic circuit cabinets

Abstract: Identical plates of essentially box-like form in which one sidewall of the box is notched out, and a transverse sidewall opposite the notch removed, the plates being stacked edgewise to form a duct assembly with alternatingly appearing openings at the top and bottom and on the front and rear side where the cutouts are positioned. The respective top and bottom openings are connected, respectively, to an ambient air manifold and a blower, and to the interior of the electronic cabinet, with the side cutouts facing, respectively ambient air and the interior of the cabinet to establish two separate air flow circuits and provide for dust-free and contamination free ventilation of the interior of the electronic cabinet while establishing efficient heat exchange by forced air flow of ambient air parallel to the ducts carrying dust-free, but heated air from the cabinet. The plates are preferably assembled together to form a set or assembly unit which can be removed from their position between the top and bottom air manifolds for removal for cleaning as a separate unit.

Numerical simulation of triple shock behavior of gaseous detonation

Abstract: A numerical analysis of performed on the nonsteady two-dimensional behavior of self-sustaining detonations. In order to produce realistic two-dimensional structures during propagation in a finite width channel, an initially assumed plane one-dimensional Chapman-Jouguet detonation was perturbed by locating up to five pairs of exothermicity spots in the passage of the detonation. The most interesting feature of the simulation was the number of triple shock waves existing after a certain time of transition from plane to periodically nonsteady two-dimensional structures. In other words, the final number of transverse shock waves becomes mostly two, which are nearly irrelevant to the assumed number of initial exothermicity spots. Details of the disappearance of several transverse waves during their rearrangement were clearly observed and are discussed. In addition, despite considerable deviation of the instantaneous propagation velocity from from the C-J value, the average of such oscillations was close to the C-J value. Thus, the results of the simulation provided the numerous features observed in the present gaseous detonations experiments. The numerical schemes utilized were the explicit first-order Van Leer and second-order MacCormack methods. The effect of artificial viscosity was examined and found to affect the transition to fully developed detonation.

Beam dampers for damping the vibrations of the skin of reinforced structures

Abstract: Beam dampers comprising a stiff, lightweight, elongate beam and layer of viscoelastic material located along an attachment flange of the beam are disclosed. The flanges of the beam is attached by the layer of viscoelastic material to the skin of a structure whose skin vibrations are to be damped. While a beam having a cross-sectional I-shape is preferred, other cross-sectional shapes can be used, such as L, Z, U and T-shapes. Regardless of their shapes, the beam acts as a constraining element for the viscoelastic attachment layer. The beam is oriented such that it is stiff in a plane transverse to the plane of the skin, resulting in thickness deformation of the layer of viscoelastic material (rather than shear deformation) converting vibration energy into heat.

Deformation microstructures in titanium sheet metal

Abstract: A metallographic study has been made of the microstructures produced by room temperature deformation of 0.6mm thick commercially pure titanium sheet metal in uniaxial, plane strain and biaxial tension. Deformation twinning becomes increasingly important as the deformation mode changes from uniaxial through plane strain to equibiaxial tension, and is more significant for strain transverse to the rolling direction than for strain in the longitudinal direction. In uniaxial tension, 1122 twins are dominant in longitudinal straining, while 1012 twins dominate in transverse straining. In plane strain and equibiaxial straining, 1012 twinning is suppressed and largely replaced by 1122 twinning. The observed changes in twin occurrence and type are attributed to the interaction of the imposed stress system and the crystallographic texture of the rolled sheet, which alters the distribution of the grain basal-plane poles with respect to the operative stress axes. In uniaxial tension parallel to the longitudinal direction, twins favored by ‘c’ axis compression are produced, while in the transverse direction twins favored by ‘c’ axis tension appear. In plane strain and biaxial tension the dominant stress is through-thickness compression, which produces twins favored by ‘c’ axis compression in nearly all cases. The alterations in twin orientation and numbers are associated with changes in stress-strain behavior. As twin volume fraction increases and twins are aligned more closely to the principal stress axis, the instantaneous work-hardening rate tends to stabilize at a nearly constant value over a large strain range.

High-frequency behavior of waveguides with finite surface impedances

Abstract: We derive the modes inside a cylindrical waveguide of finite surface impedances, assuming the waveguide transverse dimensions are large compared to the wavelength λ. This paper restricts its consideration to the modes with β e k, where β is the propagation constant and k = 2π/λ. For these modes we show that asymptotically, for large values of k, the field ψ becomes infinitesimal (of the same order of 1/k) at the boundary. Taking this into account, we obtain simple expressions for the asymptotic properties of ψ for large k. The theory applies to a variety of waveguides: corrugated waveguides, optical fibers, waveguides with smooth walls of lossy metal, and so on. An important property of the modes considered here is that their attenuation constant is very low, ie., asymptotic to 1/k2 for large k. Thus, these modes are useful for long-distance communication. Another consequence of ψ → 0 at the boundary is that for large k the distribution of ψ inside the boundary is essentially independent of the boundary parameters, i,e., independent of the surface impedances in the longitudinal and transverse directions. This consequence implies that the same radiation characteristics of the corrugated feed can be obtained using other structures and, therefore, construction can be simplified in many cases, with little sacrifice in performance. We also derive general expressions for ψ and the propagation constant β.

Method and apparatus for precisely moving a motor armature

Abstract: Electromagnetic actuators are disclosed for precisely and directly incrementing an output member along a given generally linear path. Included in one actuator is a pair of assemblies, one of which is movable with respect to the other along the given path. A first of the assemblies includes means for producing a first magnetic field extending to the second actuator assembly in a manner generally transverse to the given path. The second actuator includes energizable means alongside the path and for producing a pair of opposed, approximately equal magnetic fields, spaced along the given path. Each of these opposed fields being aligned to cooperate with the transverse field to produce a force between the assemblies tending to centrally locate the assemblies with the transverse field between the pair of opposing fields.

Measuring method and device for measuring at least one geometrical characteristic of the head of the rails of a railway track

Abstract: A measuring carriage (2,4,6), defining a transverse reference base extending parallel to the plane of the railway track, intended to be connected to a driving vehicle. This carriage comprises three detectors (13, 14, 15) located above and transversely to each line of rails (5) in order to cover a portion of the tracing of the rolling table. These detectors (13,14,15) are connected to an electronic processing circuit (16 to 23, 29) of their signals adapted to determine the amount of curvature (f) of the rolling table and its inclination (i) with respect to the plane of the railway track with the measurements representing the distances (Ya, Yb, Yc) between the reference base and the rolling table under the detectors.

Continuum distorted waves: capture into the nth shell

Abstract: The continuum distorted-wave method of Cheshire (1964) is applied to BZ++H(1s) to B(Z-1)+(n)H+, where the projectile is fully stripped. Using parabolic coordinates, a closed expression is obtained for the prior cross section summed over all normal degeneracies, the only numerical analysis being integration over the transverse component of the change in linear momentum. Results are presented for Z in (1,6) and n in (1,15) at nu =5*108 cm s-1 to illustrate deviations from Z3 and n-3 laws.

Multi-layer ink jet apparatus

Abstract: Multi-layer ink jet apparatus 10,110 includes a plurality of channels 12,112 comprising chambers including inlets and orifices 14,114 and transducers 22,122 coupled to the chambers 24,124. The various channels 12,112 are located in different layers 16,116 that stagger with respect to a plane transverse to the layers 16,116 so as to achieve a high density array of ink jet orifices 14,114.

Independent wheel suspension

Abstract: An independent wheel suspension for driven rear wheels of motor vehicles, which includes a wheel carrier guided through five single links articulated on the wheel carrier side and on the vehicle body side. The lower articulation for the wheel carrier is formed by a longitudinal link extending obliquely forwardly and inwardly as a compression strut and by a transverse link, with points of articulation of the compression strut and transverse link on the carrier being located near to one another. An upper articulation for the wheel carrier is formed by a transverse link, as a camber strut, and by a forwardly extending longitudinal link as a tension strut. A track rod extends in a transverse direction of the vehicle with a wheel spring suspension, formed by a shock absorber and non-guiding spring. The compression strut extends obliquely forwardly and inwardly with the transverse link, functioning as a spring link, in carrying the spring and shock absorber. An articulation point of the spring link on a wheel carrier side is disposed behind a transversely extending center plane of the wheel and near a longitudinally extending center phase, with the spring like extending behind the transversely extending center plane of the wheel in such a manner that an intersection point between the longitudinal axes of the compression strut and spring link is located behind a transversely extending center plane of the wheel and near the longitudinally extending center plane of the wheel. A track rod is located forwardly of the transversely extending center plane of the wheel and extends in a transverse direction obliquely forwardly and inwardly.

Theory of a thermal diffusion apparatus with transverse flows

Abstract: The article discusses a continuous thermal diffusion apparatus in which supply and removal take place at the ends of the separating slit. The dependence of the shift in concentration on the parameters of the apparatus, the properties of the mixture, and the amount of fluid removed is determined.

Theory of the transverse gradient wiggler

Abstract: We develop analytical models for the operation of gain-expanded transverse gradient wigglers in the low, medium, and high optical intensity regimes. The first two are Raman regimes in which the optical wave and transverse betatron oscillations grow simultaneously. They differ from one another only in the nature of the saturation mechanism. The third or high intensity regime is a trapped particle regime physically very similar to the regime of high extraction variable parameter wigglers.

Sacral fracture: case presentation and review.

Abstract: Sacral fractures are either transverse or longitudinal (vertical). Transverse fractures may be isolated and can be subdivided into two types. Upper transverse fractures occur in younger people and result from severe traumatic flexion of the upper body on the fixed pelvis. Lower transverse fractures result from a hard blow to the coccyx, as in a fall. Vertical fractures are essentially never isolated, always being associated with an anterior break in the pelvic ring. These result from extreme forces transmitted through the ilium. Any of these fractures can cause injury to neural elements, and surgical decompression may be indicated in certain of the transverse types.

Volumetric measurement of particles

Abstract: A B S T R A C T For measuring the volume of a particle, for example in ore sorting, the particle is caused to move past radiators which illuminate the particle in two transverse directions.Detectors provide measures of the dimensions of the particle in the transverse directions in each of a number of adjacent zones which extend through the particle in its direction of movement. For each zone a volume measurement is derived from the product of the dimensional measurements and the various volume measurements are accumulated to obtain the final volume measurement. The dimensional measurements may be made in each zone in four or more transverse directions, and may be made by means of scanning cameras to obtain a more accurate final volume measurement.

Spin waves in a spin glass

Abstract: It is shown that, in an isotropic three-dimensional spin glass with an axial anisotropy energy, three spin wave branches exist in the limit k to O. The two transverse branches have an identical gap in this limit while the longitudinal branch does not. The transverse branches are split by an external static field. Dispersion is initially quadratic for the transverse branches but linear for the longitudinal branch. For vanishingly small anisotropy all the branches are linear.

Brillouin-scattering investigation of the ferroelastic transition of benzil

Abstract: The acoustic properties of benzil are investigated by means of Brillouin scattering in both high- and low-temperature phases. The elastic constants have been measured in the trigonal phase as a function of temperature from 300 to 84 K; it appears that the constant ${c}_{44}$ is the most sensitive to the phase transition. The transverse acoustic mode of lowest energy which propagates along the $x$ axis is a soft acoustic mode related to the same order parameter as the Brillouin-zone-center $E$ soft optical mode. In the low-temperature monoclinic phase, measurements have been performed in the $z$ direction for the longitudinal and transverse lines: the variation with temperature of the frequency and linewidth of these modes has been observed to be continuous at the phase transition.

Panel latching and locking apparatus for modular pickup truck bed cover systems

Abstract: For a modular pickup bed cover system having a plurality of rigid transverse panels which slidingly fit into longitudinal channels fixed along bed side walls, interpanel latching is provided by a transverse, channel-shaped first latching member fixed across rearward ends of all except the rearmost panel and a matching, transverse, angle-shaped second latching member fixed across forward ends of all except the forwardmost panel. Fixed across the rear panel of each panel pair in panel abutment regions is an elastomeric seal. As each pair of panels is latched together, upon installation thereof into the truck bed side channels by pivotally fitting the rearward panel angle member into the forward panel channel member, the seals are compressed a preselected amount assuring weathertight interpanel sealing. Shaped end regions of the latching members cause transverse panel alignment during latching. Locking elements at rearward ends of the longitudinal channels cooperate with slightly bowed side edge regions of the panels to provide disengageable panel channel locking. Such locking also enables determination of safe interpanel unlatching on panel removal from the truck bed.

Transverse acoustic impedance of normal liquid3He

Abstract: Both the real and imaginary parts of the transverse acoustic impedance of normal liquid3He have been measured at excitation frequencies of 10 and 30 MHz, fluid pressures from 0.7 to 27 bar, and temperatures from 3 mK to 1 K. The impedance is obtained from the changes in resonance frequency and Q of a quartz crystal, which is electrically driven to oscillate in a thickness shear mode while immersed in liquid3He. These results are compared with the predictions of Fermi liquid theory, which takes into account two contributions to the impedance: (1) incoherent single-quasiparticle excitations, and (2) the excitation of the collective transverse sound mode. At 0.7 bar, our measurements of the impedance are in agreement with the predictions of Fermi liquid theory and imply that the symmetric Fermi liquid parameterF 2=1.25±0.4 ifF 1=6.3. At higher pressures, we also observe agreement in the region ωτ<0.3, where ω is the excitation frequency and τ is the quasiparticle scattering time. However, above 8 bar in the zero-sound regime (ωτ≳1), the impedance is observed to be frequency dependent, at constant ωτ. This frequency dependence cannot be explained within the present framework of Fermi liquid theory.

Spatial stability of the non-parallel Bickley jet

Abstract: The spatial stability of the plane, two-dimensional jet flow to infinitesimal disturbances is investigated by taking into account the effects of transverse velocity component and the streamwise variations of the basic flow and of the disturbance amplitude, wave-number and spatial growth rate. This renders the growth rate dependent on the flow variable as well as on the transverse and streamwise co-ordinates. Growth rates for the energy density of the disturbance and the associated neutral curves are provided as a function of the streamwise co-ordinate. Variation of growth rate of the disturbance stream function and streamwise component of velocity with the transverse co-ordinate is also given for different disturbance frequencies and streamwise locations. Results are compared with those for the parallel-flow stability analysis, and also with those for an analysis that accounts for only some of the non-parallel effects. It is found that the critical Reynolds number based on the growth of energy density of the disturbance depends on the streamwise co-ordinate and lies within the range (around 20) found experimentally, while the parallel-flow theory yields a rather low value of 4·0.

A plane stress formulation for elastic-plastic deformation of unidirectional composites

Abstract: A plane stress analysis of the elastic-plastic deformation of unidirectional composites is presented. A continuum model based on the solid-mixture concept is selected as the basis for the analysis. Model parameters, including process-dependent variables, are deduced from experiments performed on unidirectional composites. A computer program MET∗MAT has been developed accordingly and tested for a few simple in-plane loading cases. Experimental data for uniaxial tests performed in longitudinal and transverse directions and for a few biaxial tests are presented to substantiate the analysis. And, finally, application of the results to laminated metal matrix composites is discussed.

Inverse scattering of the permittivity and permeability profiles of a plane stratified medium

Abstract: It is shown that the permittivity and permeability profiles of a lossless plane stratified medium can be uniquely determined from the reflection coefficient due to transverse electric plane waves at two angles of incidence and all the frequencies. The inverse scattering problem at oblique incidence is transformed to an equivalent inverse scattering problem at normal incidences. The latter is transformed to an inverse scattering problem for the one‐dimensional Schrodinger equations, the solution of which is obtained by the Gel’fand–Levitan theory.

Work transfer device

Abstract: A work transfer device executes a generally rectilinear path of movement for progressively transferring articles between successive stations. Transverse vertical motion is imparted via a track which is bodily transversely displaced while maintained parallel with the longitudinal travel of the carriage. A roller rides in the track with longitudinal motion of the carriage. The track is displaced by a double bellcrank mechanism to shift the roller vertically and in turn impart vertical transverse motion to the device.

Acoustic microscopy of curved surfaces

Abstract: To date, imaging and metrology in the acoustic microscope have been performed exclusively on planar specimens. While imaging is accomplished by raster scanning in the plane transverse to the axis of the acoustic beam, metrology is practiced by variation of the specimen‐lens separation along the beam axis. This operation yields an acoutic material signature at a single location on the specimen plane. The two modes of operation are in effect simultaneously employed when a nonplanar surface of known curvature is scanned. The resulting images reveal concentric rings with radial periodic brightness variation if the surface is spherical in shape. The technique is demonstrated with stainless‐steel bearing balls of the type used in precision gyros. The application of this technique to the diagnostic inspection and analysis of both bearing balls and raceways are discussed. It is suggested that the obtained images represent a two‐dimensional map of elastic properties of the bearing surface regions.

A Boundary Layer Approach to the Calculation of Transverse Stresses along the Free Edges of a Symmetric Laminated Plate of Arbitrary Width Under In-plane Loading

Abstract: In order to calculate the transverse and normal stresses along a free edge in a symmetrically laminated plate under in-plane loading, we derive the boundary layer equations, and then give an approximate solution, using the complementary energy principle The method gives a stress field which satisfies all the equilibrium, continuity, and boundary conditions Several examples are given, illustrating the great versatility of the method, which is applicable regardless of the number of layers and the layer orientations