Showing papers on "Transverse plane published in 1999"

An Empirical Model of a Polar Coronal Hole at Solar Minimum

Abstract: We present a comprehensive and self-consistent empirical model for several plasma parameters in the extended solar corona above a polar coronal hole. The model is derived from observations with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) during the period between 1996 November and 1997 April. We compare observations of H I Lyα and O VI λλ1032, 1037 emission lines with detailed three-dimensional models of the plasma parameters and iterate for optimal consistency between measured and synthesized observable quantities. Empirical constraints are obtained for the radial and latitudinal distribution of density for electrons, H0, and O5+, as well as the outflow velocity and unresolved anisotropic most probable speeds for H0 and O5+. The electron density measured by UVCS/SOHO is consistent with previous solar minimum determinations of the white-light coronal structure; we also perform a statistical analysis of the distribution of polar plumes using a long time series. From the emission lines we find that the unexpectedly large line widths of H0 atoms and O5+ ions at most heights are the result of anisotropic velocity distributions. These distributions are not consistent with purely thermal motions or the expected motions from a combination of thermal and transverse wave velocities. Above 2 R☉, the observed transverse most probable speeds for O5+ are significantly larger than the corresponding motions for H0, and the outflow velocities of O5+ are also significantly larger than the corresponding velocities of H0. Also, the latitudinal dependence of intensity constrains the geometry of the wind velocity vectors, and superradial expansion is more consistent with observations than radial flow. We discuss the constraints and implications on various theoretical models of coronal heating and acceleration.

Transverse zones in the vermis of the mouse cerebellum.

Abstract: The mouse cerebellar cortex is subdivided by an elaborate array of parasagittal and transverse boundaries. The relationship between these two orthogonal patterns of compartmentation is understood poorly. We have combined the use of adult and perinatal molecular markers of compartmentation-zebrin II, calbindin, and an L7/pcp-2-lacZ transgene-to resolve some of these issues. Our results indicate that the adult cerebellar vermis is divided along the rostrocaudal axis by three transverse boundaries: through the rostral face of lobule VI, in the caudal half of lobule VII, and across the posterolateral fissure between lobules IX and X. These three boundaries subdivide the vermis into four transverse zones: the anterior zone (lobules I-V), the central zone (lobules VI-VII), the posterior zone (lobules VIII-IX), and the nodular zone (lobule X). The same zones and boundaries also can be identified in the newborn cerebellum. The parasagittal organization is different in each zone: a unique combination of Purkinje cell phenotypes is found in each transverse zone both in the neonate and the adult, and different zones have distinct developmental time tables. Furthermore, the parasagittal bands of Purkinje cells revealed in the adult cerebellar cortex by using antizebrin II immunocytochemistry are discontinuous across the transverse boundaries. These data suggest that the transverse zones of the vermis form first during development and that parasagittal compartmentation develops independently in each transverse zone.

Continuous high speed tomographic imaging system and method

Abstract: The continuous, high speed, tomographic imaging system moves a closed package containing concealed objects continuously along a conveyor belt past three spaced sensing stations. At each sensing station a plurality of X-ray sources each emit a fan beam in the same scan plane which passes through the package to a plurality of detectors opposite to the X-ray sources. One scan is a vertical perpendicular scan plane relative to the direction of travel of the package along the conveyor belt and the remaining two scan planes are horizontal scan planes at right angles and transverse to the direction of travel. One horizontal scan plane is a left to right scan plane while the remaining scan plane is a right to left scan plane. Each detector provides multiple energy outputs (5) for the same data point in a scan slice, and the detector outputs are stored until all three sensing stations have scanned the same cross sectional view of the package in three directions. Scans are sequentially taken as the package moves continuously through the sensing stations and scanned data corresponding to cross sectional views of the package is accumulated. The stored data is calibrated and normalized and then used in a CT algebraic reconstruction technique. This is a multispectral CT reconstruction, where the density of a reconstructed object is determined by the attenuation which it causes in the scanning X-rays while the atomic number of the object is determined from the multiple energy scan output. In a classifier, the density and atomic number are compared to a stored look up table containing density and atomic number identification values for specific objects to be located.

Light concentrator photovoltaic module method of manufacturing same and light concentrator photovoltaic system

Abstract: A light concentrator photovoltaic module includes a medium having a light receiving plane, a plurality of photovoltaic elements arranged in a spaced relationship with the light receiving plane, and a light reflecting plane for conducting light incident upon the light receiving plane but is not directly received by the photovoltaic elements to the photovoltaic elements. The light reflecting plane has a structure as viewed on a cross section in a plane transverse to the module light receiving plane and traversing adjacent two photovoltaic elements and a light reflecting member therebetween such that the light reflecting plane includes, at least two first inclined planes and at least two second inclined planes, the first inclined planes being rightwardly ascending while the second inclined planes are leftwardly ascending, respectively, at least two first inclined planes being arranged on a right side of a middle point of a distance between the adjacent two photovoltaic elements while at least two second inclined planes being arranged on a left side of the middle point.

Surface electromagnetic waves in two-dimensional photonic crystals: Effect of the position of the surface plane

Abstract: A semi-infinite photonic crystal can support electromagnetic wave propagation at its surface By using the supercell method, we studied in detail the properties of these (nonradiative) modes in crystals of two-dimensional periodicity constituted by parallel rods of square cross section The rods cut the plane of periodicity (001) at the sites of a square lattice, and the sides of the rods have the same orientation as the lattice We have performed calculations for crystals of air cylinders in a dielectric background The Bloch-type surface waves are assumed to propagate at the (100) surface in the [010] direction For both transverse electric and transverse magnetic polarizations, we found that the dispersion curves of the surface modes and their field confinements at the surface are strongly dependent on the crystal termination, that is, on the position of the cut plane through the rods We also found that the degree of localization of the fields at the surface depends on the position of the mode within the band gap Plots of the field intensity show that the TM waves are more strongly localized than the TE waves

Transverse Normal Stress Effects in Multilayered Plates

Abstract: An evaluation of transverse normal stress σ zz effects in multilayered plate modeling is given in this paper. Mixed theories with continuous interlaminar transverse shear and normal stresses have been formulated on the basis of Reissner's theorem (Reissner, 1984). The case in which the number of the displacement variables preserves independence by the number of constitutive layers, N 1 , has been investigated. Classical models based on standard displacement formulations have been discussed for comparison purposes. The analysis of transverse stress effects has been conducted by allowing a constant, linear, and higher-order distribution of the transverse displacement components in the plate thickness directions. Related two-dimensional models are compared for the static response of symmetrically and unsymmetrically layered, simply supported plates made of isotropic as well as orthotropic layers. The conducted numerical investigation and comparison with available results have above all led to the following conclusions. The possibility of including σ zz makes the used mixed theories more attractive that other available modelings. σ zz plays a fundamental role in thick laminate plates analysis. Such a role increases in transversely anisotropic multilayered plate analysis. With an increase of the plate thickness, a very accurate description of σ zz requires modelings whose number of independent variables depends on N 1 .

Floating apparatus and method for extracting power from sea waves

Abstract: An apparatus for extracting power from ocean waves comprises a number of buoyant cylindrical body members (2, 3, 4) connected together at their ends to form an articulated chain-like structure (1). Each pair of adjacent cylindrical members is connected to each other by a coupling member (5a, 5b) which permits relative rotational movement of the cylindrical members about at least one transverse axis (40). Adjacent coupling members may permit relative rotation about mutually orthogonal transverse axes (A, B). Each coupling member is provided with elements such as a set of hydraulic rams (33, 34, 35) which resist and extract power from the relative rotational movement of the body members, and which can provide applied constraints to rotation about one or both of the transverse axes. The transverse axes of rotation (A, B) are skewed from the horizontal (41) and vertical (42) by a roll bias angle (γ), selected to optimise the dynamic response of the apparatus to incoming waves. The roll bias angle (γ) is applied by differential ballasting of the body members (2, 3, 4) and/or mooring constraints.

Apparatus and method for three-dimensional contouring

Abstract: A contouring (20) device and method for contouring three-dimensionally curved surfaces includes an elongated contouring assembly (28) that is supported at opposite ends by a pair of fluid cylinders (52,54). The fluid cylinders are controlled to raise and lower the ends of the contouring assembly independently of each other, thereby allowing the contouring assembly to create a three-dimensionally curved surface as it passes over an area to be contoured. The control of one of the fluid cylinders (52) is based on a comparison of the measured position of a first end of the contouring assembly with a profile of the surface to be leveled that is stored in a computer memory. The measurement of the position of the first end of the contouring assembly is achieved by a tracking device (58) which tracks the position of a target (56) positioned on the first end of the contouring assembly and which determines the three dimensional position of the target. A proximity sensor (78) measures the position of the second end of the contouring assembly from a surface and outputs a control signal that adjusts the height of the second end of the contouring assembly to follow the surface. Alternatively, a second target positioned on the second contouring assembly end is tracked by a second tracking device to determine the three-dimensional position of the second end. The contouring assembly preferably has a plow (32), rotating auger (36), and a vibratory screed (34) positioned adjacent and parallel to one another in an orientation transverse to the direction of motion of the contouring assembly. The plow, rotating auger, and vibratory screed are all pivotable about an axis parallel to their longitudinal direction. A pivot or tilting controller controls the tilting of the plow, rotating auger, and vibratory screed to follow the slope of the profile stored in computer memory.

Transverse-electric and transverse-magnetic beam modes beyond the paraxial approximation.

Abstract: Transverse-electric and transverse-magnetic beam modes are considered based on a theory in which complex dipole sources and sinks are oriented along the beam axis; the theory is similar to one that was previously presented for transverse dipoles. The field in the region of the waist is explored. Modes with such polarization have been reported from a wide range of laser types.

Method for estimating and imaging of transverse displacements, transverse strains and strain ratios

Abstract: The present invention is directed toward a new method that combines interpolation between neighboring A-lines with cross-correlation for high precision estimation of the transverse displacement Due to this high precision lateral estimation, the method of the present invention can produce quality lateral-elastograms that display the lateral component of the strain tensor These higher precision lateral displacement estimates also allow a finer correction for the lateral decorrelation that corrupts the axial estimation The method of the present invention may be employed to divide the lateral-elastogram by the axial-elastogram on a pixel-by-pixel basis, in order to produce a new image that displays the distribution of Poisson's ratios in the tissue

Excitation of Oscillations in Photospheric Flux Tubes through Buffeting by External Granules

Abstract: We examine the excitation of transverse (kink) and longitudinal (sausage) waves in magnetic flux tubes by granules in the solar photosphere The investigation is motivated by the interpretation of network oscillations in terms of flux tube waves We model the interaction between a granule, with a specified transverse velocity, and a vertical flux tube in terms of the Klein-Gordon equation, which we solve analytically as an initial value problem for both wave modes, assuming the same external impulse The calculations show that for magnetic field strengths typical of the network, the energy flux in transverse waves is higher than in longitudinal waves by an order of magnitude, in agreement with the chromospheric power spectrum of network oscillations observed by Lites, Rutten, & Kalkofen But for weaker fields, such as those that might be found in internetwork regions, the energy fluxes in the two modes are comparable This result implies that if there are internetwork oscillations in magnetic flux tubes, they must show the cutoff periods of both longitudinal and transverse modes at 3 minutes and at 7 minutes or longer We also find that granules with speeds of about 2 km s-1 can efficiently excite transverse oscillations in frequent short-duration (typically 1 minute) bursts that can heat the corona

Transverse spectra of radiation processes in a medium

Abstract: A formalism is developed for evaluation of the transverse momentum dependence of the cross sections of radiation processes in a medium. The analysis is based on the light-cone path integral approach to the induced radiation. The results are applicable in both QED and QCD.

Application of the Tsai–Wu Quadratic Multiaxial Failure Criterion to Bovine Trabecular Bone

Abstract: As a first step toward development of a multiaxial failure criterion for human trabecular bone, the Tsai-Wu quadratic failure criterion was modified as a function of apparent density and applied to bovine tibial trabecular bone. Previous data from uniaxial compressive, tensile, and torsion tests (n = 139 total) were combined with those from new triaxial tests (n = 17) to calibrate and then verify the criterion. Combinations of axial compression and radial pressure were used to produce the triaxial compressive stress states. All tests were performed with minimal end artifacts in the principal material coordinate system of the trabecular network. Results indicated that the stress interaction term F12 exhibited a strong nonlinear dependence on apparent density (r2 > 0.99), ranging from -0.126 MPa-2 at low densities (0.29 g/cm3) to 0.005 MPa-2 at high densities (0.63 g/cm3). After calibration and when used to predict behavior of new-specimens without any curve-fitting, the Tsai-Wu criterion had a mean (+/- SD) error of -32.6 +/- 10.6 percent. Except for the highest density triaxial specimens, most (15/17 specimens) failed at axial stresses close to their predicted uniaxial values, and some reinforcement for transverse loading was observed. We conclude that the Tsai-Wu quadratic criterion, as formulated here, is at best only a reasonable predictor of the multiaxial failure behavior of trabecular bone, and further work is required before it can be confidently applied to human bone.

Convective versus absolute instability in mixed Rayleigh Bénard Poiseuille convection

Abstract: Transition from convective to absolute instability in Rayleigh–Benard convection in the presence of a uni-directional Poiseuille flow is studied. The evaluation of the long-time behaviour of the Green function in the horizontal plane allows the determination of regions of convective and absolute instability in the Rayleigh–Reynolds number plane as a function of Prandtl number. It is found that the mode reaching zero group velocity at the convective–absolute transition always corresponds to transverse rolls, while the system remains convectively unstable with respect to pure streamwise (longitudinal) rolls for all non-zero Reynolds numbers. Finally, the roll pattern within the entire wave packet and in particular near its centre is elucidated and possible connections between experiments and our findings are discussed.

On transverse matrix cracking in cross-ply laminates loaded in simple bending

Abstract: A one-dimensional analysis of a cross-ply laminate, containing cracked transverse plies, loaded in flexure is presented. Simple bending theory is used in conjunction with a shear-lag analysis, to calculate the degraded longitudinal modulus of a cracked transverse ply, enabling the flexural modulus of the laminate to be determined. The solution is shown to agree well with a more sophisticated stress transfer model in the literature. The analysis is then extended to calculate the applied bending moment at transverse crack onset under flexural loading using a fracture mechanics approach. The results suggest that the in situ transverse ply stress at which matrix cracking commences for the beam loaded in flexure is very close to the stress level at which the same ply would crack if the laminate were loaded in tension.

A Study of Transverse Normal Stress Effects on Vibration of Multilayered Plates and Shells

Abstract: This paper evaluates transverse normal stress σzzeffect on vibration of multilayered structures. To this purpose a mixed plate model initially introduced by Toledano and Murakami has been extended to dynamics analysis of double curved shells. These models allow both continuous interlaminar transverse shear and normal stresses as well as the zigzag form of the displacement distribution in the shell thickness directions to be modelled. Governing equations have been derived by employing a Reissner's mixed theorem. Classical models on the basis of standard displacement formulations have been considered for comparison purposes. The evaluations of transverse stress effects have been conducted by comparing constant, linear and higher order distributions of transverse displacement components in the plate thickness directions. Free vibrational response of layered, simply supported plates, cylindrical and spherical shells made of isotropic as well as orthotropic layers has been analyzed. The numerical investigation carried out and comparison with earlier results has concluded that: • 1. The possibility of describing interlaminar continuous transverse normal stress makes the mixed theories more attractive with respect to other available modelling. • 2. Any refinements of classical models are meaningless, unless the effects of interlaminar continuous transverse shear and normal stresses are both taken into account in a multilayered shell theory.

Transverse Spectra of Radiation Processes in Medium

Abstract: We develop a formalism for evaluation of the transverse momentum dependence of cross sections of the radiation processes in medium. The analysis is based on the light-cone path integral approach to the induced radiation. The results are applicable in both QED and QCD.

Bending of Curved Sandwich Panels with a Transversely Flexible Core-Closed-Form High-Order Theory:

Abstract: The bending behavior of a curved sandwich panel with a transversely flexible core, ie, "soft" in the out of plane direction is derived It is formulated using a rigorous systematic closed-form approach based on variational principles The effects of the transversely flexible core are incorporated resulting in non-linear patterns, denoted also as high-order effects, for the inplane and the transverse deformations through the height of the core The governing equations along with the associated boundary and continuity conditions for a general type of sandwich panel, ie, unidentical skins, composite laminated or metallic and a "soft" core are derived General type of boundary conditions, including spring conditions, as well as different conditions at upper and lower skins at the same section, are implemented and the effects of "stiff' edge inserts, denoted as global boundary conditions, along with the induced localized effects are considered Localized effects at support regions with or without edge stif

A spectral theory for fingering on a prewetted plane

Abstract: A spectral theory is formulated to quantify the dynamic sensitivity and stability of a liquid front spreading over a prewetted inclined plane. Sensitivity of the front to surface heterogeneity is captured by the stable continuous essential spectrum of a non-normal linear operator over a practically infinite domain. Small-amplitude disturbances on the prewetted film are convected by this mechanism to the front and focused into a sharp but transient spike with a greatly magnified amplitude. A specific transverse wavelength is selected during this transient excitation. However, this amplification can only lead to fingering and select the transverse wavelength if a point eigenvalue of the discrete spectrum with the same wavelength is unstable. This discrete mode is resonantly excited by the disturbance convected and amplified by the stable essential spectrum. The preferentially excited point eigenvalue is nearly neutral due to the translational invariance of the unfingered front and has a much smaller growth rate and much shorter transverse wavelength than the most unstable discrete mode. For a range of inclination angles, it is stable for thick fronts but destabilizes far downstream when the thinning film reaches a critical thickness and a bump appears on the front. Experiments and numerical simulation of fingering on a prewetted plane verify these distinct roles of the essential and discrete spectra in this supercritical fingering instability and quantitatively confirm the predicted fingering position.

The influence of lateral boundary conditions on the asymptotics in thin elastic plates

Abstract: Here we investigate the limits and the boundary layers of the three-dimensional displacement in thin elastic plates as the thickness tends to zero in each of the eight main types of lateral boundary conditions on their edges: hard and soft clamped, hard and soft simple support, friction conditions, sliding edge, and free plates. Relying on construction algorithms [M. Dauge and I. Gruais, Asymptotic Anal., 13 (1996), pp. 167--197], we establish an asymptotics of the displacement combining inner and outer expansions. We describe the two first terms in the outer expansion: these are Kirchhoff--Love displacements satisfying prescribed boundary conditions that we exhibit. We also study the first boundary layer term: when the transverse component is clamped, it has generically nonzero transverse and normal components, whereas when the transverse component is free, the first boundary layer term is of bending type and has only its nonzero in-plane tangential component.

Transverse Shear and Normal Deformation Theory for Bending Analysis of Laminated and Sandwich Elastic Beams

Abstract: The influence of transverse normal strain on bending analysis of cross-ply laminated and sandwich beams is presented. A higher-order shear deformation beam theory is developed. Euler-Bernoulli classical, Timoshenko first-order and simple higher-order theories have been also used in the analysis. The governing equations for a beam composed of orthotropic layers and subjected to any given mechanical load distribution are derived. Making use of Navier-like approach, exact solutions are obtained for cross-ply laminated and sandwich beams subjected to arbitrary loadings. Numerical results for beams with the simply-supported boundary conditions are presented. The effects due to transverse normal strain, transverse shear deformation and number of layers on the static response of the beams are investigated.

Measurement of the Spin-Density Matrix Elements in Exclusive Electroproduction of rho^0 Mesons at HERA

Abstract: Exclusive electroproduction of rho^0 mesons has been measured using the ZEUS detector at HERA in two Q^2 ranges, 0.25

Deformation, yield and fracture of unidirectional composites in transverse loading 1: Influence of fibre volume fraction and test-temperature

Abstract: The influence of the fibre volume fraction and test-temperature on the transverse tensile properties of glass fibre reinforced epoxy is studied using experimental and numerical techniques. The numerical analyses are based on micromechanical models with square and hexagonal fibre packings. Special attention has been directed towards the identification of the necessary failure criteria. Using a von Mises failure criterion, an increase in transverse tensile strength is predicted at higher fibre volume fractions with both models. This is in good quantitative agreement with experimentally determined transverse flexural strengths. With decreasing test-temperatures, higher transverse strengths are obtained. This is primarily caused by the temperature dependence of the yield stress of the matrix. The counteracting influence of the residual thermal stresses and the temperature dependent matrix ductility consequently proved to be less significant for the transverse strength.