A time integration method for analysis of dynamic systems using domain decomposition technique

This paper presents a precise and stable time integration method for dynamic analysis of vibration or multibody systems A total system is divided into several subsystems and then responses are calculated separately, while the coupling effect is treated equivalently as constant force during time steps By using iterative procedure to improve equivalent coupling forces, a precise and stable solution is obtained Some examples such as a seismic response and multibody analyses were carried out to demonstrate its usefulness

     

Spatial correlation coefficients of rainfall intensity inferred from statistics of rainfall intensity and rain attenuation

On the basis of the reliable statistics of rainfall rate and rainfall attenuation for 8 localities in Europe, the spatial correlation coefficient of point rainfall intensity was inferred for each locality from the cumulative distributions of attenuation and rainfall intensity by inversely applying the modified Morita and Higuti rainfall attenuation prediction method. It was found that for European regions the spatial correlation coefficient with an exponential dependence on the horizontal distance is more appropriate for the prediction of rainfall attenuation than that proposed by Morita and Higuti for the Japanese climate. It was also found that although the spatial correlation characteristic varies significantly from one locality to another its variance is not so significant within a particular ccir rainfall climatic zone. This suggests that in predicting the rainfall attenuation it is desirable to employ the spatial correlation coefficient appropriate for the locality to be estimated.     

FFTA: A fast fault tree analysis program

This paper presents a computer program for fault tree analysis. The algorithm is a bottom-up algorithm and the detailed procedure of the program is explained. The analyses are performed for six sample fault trees and the results are compared with those obtained by the BAM and CUT codes. This program has a ten to thousand times faster calculation speed compared with the BAM and CUT codes.     

Separation of PRMMC into matrix alloy and reinforcements by nozzle filtering method

The SiC_P/Al–4 mass%Cu alloy composites fabricated by a low-pressure infiltration process (LPI process) were remelted and separated by nozzle filtering method. In the separation process, the PRMMC specimen was placed in a container with a small nozzle at the bottom. The molten PRMMC was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of SiC particles and a part of the matrix alloy. The particle volume fraction of the remainder was higher than that of the original PRMMC and the remainder would work as a filter to separate SiC particles from the matrix alloy melt. When nozzle tip angle was ranged from 60° to 120°, about 80% of matrix alloy in the PRMMC was separated and few SiC particles were observed in the separated matrix alloy. The surface of recovered SiC particles became slightly roughened due to the reaction with the molten matrix during the separation process. However, this is not expected to affect their reuse.     

On-Site Fabrication of Crystalline Cerium Oxide Films and Patterns by Ink-Jet Deposition Method at Moderate Temperatures

Crystalline CeO₂ films and patterns have been successfully fabricated in a "single-step process" at moderate temperature. In this process, the combination of the ink-jet technique and depositing the precursor on a hot substrate (≤300°C) gave crystalline CeO₂ without further heat treatment. X-ray diffraction analysis revealed that the phase formed was crystallized ceria with nanosized (<10 nm) crystallites. The film thickness was several hundred nanometers and the pattern width was about 150 μm. Scanning electron microscopy analysis showed that the films and patterns were free of cracks and adhered to the substrate. This is the first report about the direct patterning of crystalline CeO₂ without postfiring or posttreatments like masking, etching, etc.     

A Characterization of Planar Graphs by Pseudo-Line Arrangements

Let Γ be an arrangement of pseudo-lines, i.e., a collection of unbounded x -monotone curves in which each curve crosses each of the others exactly once. A pseudo-line graph (Γ, E) is a graph for which the vertices are the pseudo-lines of Γ and the edges are some unordered pairs of pseudo-lines of Γ . A diamond of a pseudo-line graph (Γ, E) is a pair of edges {p,q} , {p',q'}∈ E , {p,q} ∩ {p',q'}= , such that the crossing point of the pseudo-lines p and q lies vertically between p' and q' and the crossing point of p' and q' lies vertically between p and q . We show that a graph is planar if and only if it is isomorphic to a diamond-free pseudo-line graph. An immediate consequence of this theorem is that the O(k ^1/3 n) upper bound on the k -level complexity of an arrangement of straight lines, which was very recently discovered by Dey, holds for an arrangement of pseudo-lines as well.     

Conceptual design of rain radar for the tropical rainfall measuring mission

Specifications for a spaceborne rain radar for tropical rainfall measurement are described. A spaceborne rain radar has problems peculiar to rain observation from space. The radar must have a fast scanning mechanism to cover a large swath. Very weak rain echoes compared to the sea or land surface signal must be detected. These capabilities must be attained under the severe power consumption and mass limitations of the satellite bus. The fast scanning requirement forces application of an electrically scanning mechanism. This requirement also causes a severe limitation of the available number of independent samples. The requirement for weak rain echoes excludes application of the pulse compression technique, which is a very conventional technique for other active microwave sensors on board satellites. Under these constraints, a rain radar with an electrically scanning planar antenna at 13-8 GHz is proposed.     

Transport of direct dye into cellulose membrane

The dyeing process for a cellulose membrane–direct dye system is analyzed based on a parallel transport mechanism of surface and pore diffusion with Freundlich isotherm. Numerical solutions were obtained in order to clarify how the surface and pore diffusion resistances affect the uptake curve. The numerical solutions were also compared with an analytical solution for surface diffusion control to establish the range where the analytical solution can be considered as an acceptable approximation. The uptake curves in the cellulose membrane-chromophore (C.I. Direct Yellow 12) system in the presence of inorganic electrolyte were measured. The rate of adsorption and the maximum amount of adsorption increased with an increase in the concentration of those electrolytes. The rate of adsorption was approximately controlled by the surface diffusion rather than by pore diffusion. The surface diffusivities of the dye were little affected by either the concentration and or nature of the electrolyte.     

Growth and led evaluation ofN-type conductive lec gaas co-doped with in and si

Dislocation-free and low dislocation densityn-type conductive GaAs crystals, 50 mm in diameter, were grown by the In and Si co-doping LEC technique. Two-dimensional LED arrays were fabricated on substrates obtained from these crystals by the MOCVD technique and the influence of the In doping on the LED characteristics was examined. The light output power of LEDs fabricated on co-doped substrate with an In concentration of 1 ×10²⁰atoms/cm³ are low and are non-uniformly distributed, as compared with the boat-grown substrate, even though the co-doped substrate is dislocation-free. However, the LED properties of a substrate with an In concentration of 2 × 10¹⁸atoms/cm³ are the same as those of a boat-grown substrate. The light output power of the LEDs becomes higher as the In concentration in the substrate decreased.