Effect of friction,strain hardening,and strain rate hardening on the metal flow in rod extrusion

The metal flow in a rod extrusion is theoretically discussed in relation to a frictional condition, strain hardening and strain rate hardening. An existing rigid plastic FEM-program was modified in order to take a rate sensitivity of a material into consideration through a constitutive equation of the form. An interfatial friction was incorporated by a constant Coulomb-frictional coefficient. When the frictional coefficient is smaller than 0.1, a large effect of the friction does not appear. The larger the n-value is, the stronger the distortion of the grid in a billet becomes even under small frictional resistance. The effect of the m-value is similar qualitatively to that of the n-value. When the rate sensitive material is extruded at very low punch speed under large frictional resistance, the material is strained very irregularly all over the billet at an early stage.     

Large nonlinear optical effect in an InGaAs/InAlAs multiquantum well waveguide

All-optical refractive nonlinearity in a passive InGaAs/InAlAs multiquantum well waveguide is evaluated for TE and TM modes at 1.55 mu m wavelength and room temperature. A quarter wavelength change in the optical path length is observed at an input pump light power of 6.5 mW for 1.47 mu m wavelength in a 960 mu m long device. Nonlinear refractive index n/sub 2/ is evaluated to be -1.2*10/sup 6/ and -0.5*10-6cm/sup 2//W for the TE and the TM modes, respectively.<>     

Interlayer couplings and magnetoresistance effects of Fe/Cr/Fe/Ni-Fe/NiO sandwiches

Interlayer coupling between Fe layers and magnetoresistance effect have been investigated in Fe/Cr/Fe/Ni-Fe/NiO sandwiches. The interlayer coupling between two Fe layers oscillates as the thickness of Cr layer changes. The strongest antiferromagnetic coupling is observed when the thickness of the Cr layer is 1.2 nm. The highest magnetoresistance ratio due to spin-dependent scattering is only 0.13%. The low magnetoresistance ratio is thought to be caused by high resistivity of the Cr layer. This revised version was published online in November 2006 with corrections to the Cover Date.     

Calculations from texture of earing in deep drawing for FCC metal sheets

The present study aims to calculate the height at each peripheral position of a cup drawn from polycrystalline sheet using texture data. In the analytical treatment the polycrystalline sheet is simplified to an aggregation of many single crystals with various orientations, and the texture is represented by a three-dimensional crystallite orientation distribution function. The ear is calculated crystallographically using the orientation distribution function as a volume fraction of a certain oriented crystal. In the experiment aluminium, Al-Mg alloy and copper sheets which are treated under various conditions of cold rolling and heat treatment are used. The average textures over the thicknesses of the sheets are measured by the Schulz reflection method. The calculated ears based on the measured textures are compared with the experimental ears for each material. The results show that all the principal features of the ears of drawn cups are predicted satisfactorily by the calculation.     

A New Aroma-Bearing Substance from Shiitake, an Edible Mushroom

SUMMARY— Investigations on the physico-chemical properties and a sensory evaluation as a component of Shiitake flavor were carried out with lenthionine, a substance which was isolated from dried Shiitake mushroom. Lenthionine is practically insoluble in water but soluble in non-polar solvents. Its stability in an aqueous solution changes greatly with the pH of the solution.
Lenthionine was identified as a significant component in the aroma of Shiitake mushroom and its detectable threshold level is at a concentration between 0.27 and 0.53 porn in water. This new aroma-bearing substance will be used as a flavor additive in various foods.     

A new methodology to guarantee the structural integrity of Al2O3/SiC composite using crack healing and a proof test

Structural ceramics are brittle and sensitive to flaws. As a result, the structural integrity of a ceramic component may be seriously affected by inherent flaws. Self-crack-healing is an excellent answer to this problem. At the moment, however, there is no technique to heal embedded flaws. Therefore, a technique to guarantee the reliability of ceramic components is demanded, and thus a technique using crack healing followed by proof test was developed by K. Ando et al. to accomplish this. With this technique, testing the mechanical behaviour of the crack-healed zone is very important for ensuring the structural integrity of a ceramic component. In this study, first Al₂O₃/SiC composite with an excellent crack-healing ability was sintered. Second, a crack was introduced on the sample (3 mm × 4 mm × 36 mm), which reduced the bending strength by about 80%, and subsequently the crack was healed. Third, a proof test was carried out on the crack-healed sample. Last, using the crack-healed and proof-tested sample, a fracture test was carried out up to 1373 K. The measured minimum fracture stress (σ_Fmin) was compared with the theoretical minimum strength (σ_G) from room temperature (R.T.) to 1373 K. It was concluded that σ_G showed good agreement with σ_Fmin up to 1373 K and that the crack healing followed by proof test was an excellent technique to increase the survival probability by administering a proof test and to guarantee the reliability of Al₂O₃/SiC composite.     

INFORMATION FILTERING FOR EMERGENCY MANAGEMENT

Information filtering is an intelligent function that selects the relevant messages and items of use or interest to the user from a large amount of incoming information. This function has become very important for the rapid development of network technology. This article focuses on information filtering for the management of emergency situations. We believe that special purpose-built "information filtering systems" should be developed to cope with the problem of information overload in emergency management. In this article, we first investigated features of information in emergent situations and then proposed an information filtering system for emergency management. The proposed system is composed of two parts: causal analysis and information classification. A prototype system has been developed and its effectiveness was evaluated by experiments.     

The present and future status of Japanese foundry industry

An introduction is given in detail about the current situation of Japanese foundry industry in 2006 from aspects such as the delivery structure of castings, scale and numbers of foundries, current profit of foundry industry as well as the background of lower profitability, etc. The development trend of Japanese foundry industry was also predicted, such as the transition of foundries from family business to modern company business, the improvement of rejection ratio and yield, application of IT to production and management, human resources and the challenge for zero emission and so on.