Variation In Radial Direction Research Articles

A simple analytical model for an elastohydrostatic thrust bearing

A new design of an elastohydrostatic bearing with a structurally elastic pad is theoretically analyzed. A single recess circular thrust bearing has the upper pad provided with a large cavity, covered with an elastic metallic membrane. The latter deflects under the pressure distribution in the bearing, creating a radial convergent gap. A simplified axi-symmetric analytical model based on two assumptions is proposed: (i) parabolic approximation for the elastic component of the film thickness and (ii) the maximum elastic deformation of the membrane is calculated analytically using a simplified linear pressure variation in radial direction on the land. Thus, the coupled equations for fluid film and elastic deformation can be solved successively and the bearing performance characteristics can be easily calculated. A parametric analysis, function of a complex elastic parameter and relative recess radius was performed, showing higher load capacity and lower friction similarly to what was previously obtained using rubber-based compliant bearings. A first stage of validation of the analytical model consisted in using a structural finite element model. For the sake of simplicity, the pressure distribution was written in an APDL code using the ANSYS program. The comparison showed small differences for typical values of the recess radius.

Variation of permittivity in radial direction in concentric half-split cylindrical dielectric resonator antenna for wideband application

Design and development of wideband concentric half-split cylindrical dielectric resonator antenna (CDRA) using permittivity variation in radial direction has been proposed in this article. The homogeneous, two-layer and three-layer concentric half-split CDRAs have been discussed separately. The effect of antenna parameters such as layer arrangement, geometrical parameters, and probe length are investigated. To validate the results, two-layer and three-layer concentric half-split CDRA have been fabricated using commercially available microwave laminates. In each case, the input reflection coefficient, radiation pattern, and antenna gain are simulated and measured. Good agreements between simulated and measured results have been obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:321–329, 2015.

Simulation of a polarization pupil filter using magneto-optic lens under elliptically polarized illumination

An active lens made of magneto-optic glass element and placed before a linear polarizer is shown to simulate the pupil plane amplitude and phase filter due to thickness dependent Faraday rotation variation in radial direction. Changing the applied magnetic flux density can dynamically change the pupil characteristics. The variation of intensity point spread function (IPSF) and optical transfer function (OTF) with magnetic flux density for elliptically polarized input beam is studied.

Heat transfer and kinetics of bulk growth of silicon carbide

A kinetics model for silicon carbide growth is proposed that is based on Hertz–Knudsen equation and relates supersaturation to the growth rate. The species concentration profiles in the growth chamber are obtained by using a one-dimensional advective mass transfer model assuming that the axial temperature gradient in growth chamber is larger than the radial temperature gradient. The RF induction heating and heat transfer in a 1.5-in system is calculated by using a magnetic vector potential theory and a coupled radiation and conduction model. Axisymmetric, two-dimensional growth rate profiles for different ingot lengths are obtained by considering the temperature variation in radial direction.

MHD Spectrum of Coronal Rays

AbstractThe MHD spectrum of discrete kink modes is derived for a cylindrical, static and isothermal plasma with spatial variations in radial direction only. Such a configuration models, in first approximation, the long and almost radially oriented fine structures of the solar corona denominatedcoronal rays, whenever cylindrical symmetry holds. Since here gravity is not taken into account, the application of the results is limited to longitudinal wavelengths not greater than the density scale of height. The predicted eigenfrequencies of slow magnetoacoustic modes are potentially observable in eclipses and may constitute a diagnostics of the axial electric current and the degree of twisting of the magnetic field.

電動式ＣＮＣ粉末成形プレスを利用した継ぎ足し成形法による粉末高速度鋼部品の製造 圧縮軸方向密度分布への影響

Water-atomized high speed steel powder was pressed into a component with high aspect ratio by repetitive compaction process using electric drive CNC press and the uniformity of green density along the compacting axis was investigated. For the dimensional accuracy the uniform density distribution is very important because of large linear shrinkage ratio of about 10% during vacuum sintering. The CNC compacting press has superior versatility of compaction sequences and makes it possible to minimize the difference of local green density by repetitive compaction which consists of several sets of powder filling and compaction.The green compact(φ14×45) by repetitive compaction showed fairly uniform density distribution and smaller local density variation compared with green compact by conventional single compaction. The measured profile curves along a side wall of sintered parts were in good agreement with the predicted density distribution and the dimensional variation in radial direction was reduced. Tensile strength was equivalent to that of conventional part and the breakage didn't occur at the joining point. The experimental results shows the possibility of near-net-shape production of P/M high speed steel parts with large height.