Study of Ultrasonic Machining by Longitudinal-torsional Vibration for Processing Brittle Materials-observation of Machining Marks

AbstractThe ultrasonic machining is a processing method using both the ultrasonic vibration of the tool horn and abrasive slurry. We studied a new ultrasonic machining method using ultrasonic complex vibration caused by the longitudinal and torsional vibration. In previous studies, we found that the machining speed and the machining accuracy when using a complex vibration are improved as compared with that using conventional ultrasonic machining method. However, the mechanism of ultrasonic machining using longitudinal-torsional vibration has not been clarified. In this presentation, we study that the observation of machining marks of soda-lime glass caused by ultrasonic machining using complex vibration

Mechanisms of Significant Precipitation Hardening in a Medium Carbon Bainitic Steel by Complex Nanocarbides Composed of Nb, Ti and V

Precipitation-hardening behavior of various medium carbon bainitic steels with added elements of Nb, Ti and V was systematically investigated. Complex nanocarbides composed of Nb, Ti and V precipitated after aging in the steel with multiple additions of all the elements, whereas those with added individual elements were simple MC types. The amount of precipitation hardening (ΔHv) after aging at 873 K of the former steel was approximately 90 ΔHv, while those of the latter were less than 40 ΔHv at best. Therefore, significant precipitation hardening took place by multiple element addition. The different amount of precipitation hardening depending on added elements was reasonably understood by considering misfit parameters between carbides and ferrite matrix

H_2 Dissociative Adsorption at the Armchair Edges of Graphite

We investigate and discuss how hydrogen behaves at the edges of a graphite sheet, in particular the armchair edge. Our density functional theory-based calculations results show that, in contrast to the zigzag edge [cf., e-J. Surf. Sci. Nanotech. 2 (2004) 77], regardless of orientation, there is an activation barrier hindering H_2 dissociation at the armchair edges. And once they do get dissociatively adsorbed at the armchair edges, we find that it would be extremely hard to desorb the H from their adsorption sites at the armchair edges. Furthermore, we also found that, consistent with our earlier conclusions [cf., J. Phys. Soc. Jpn. 72 (2003) 1867], it is unlikely that we would find a whole H_2 in between plain graphite sheets.Comment: 4 pages, 5 figures, preprin

Material Recycling of Municipal Waste Slags by Using Phase Separation of Glass

A novel recycling process of municipal waste slags obtaining Fe-free colorless materials was developed by using a phase separation of borosilicate glass. B(2)O(3) was added to a simulated waste slag to promote the phase separation. The slag glasses were heat-treated above glass transition temperatures, from which phase separation was successfully induced. The phase-separated slag glasses were still colored in black due to Fe ions, and after soaking in acid, they were successfully bleached, obtaining colorless solids. According to compositional analyses, no Fe ions were confirmed in the remaining insolubles, indicating that Fe ions were preferentially incorporated into the borate-rich phases soluble in acid. The main constituent of the colorless solids was SiO(2) and the end products obtained in the present process were expected as an alternative of pure silica glass

ON ANALYTICITY OF THE LpL^p-STOKES SEMIGROUP FOR SOME NON-HELMHOLTZ DOMAINS

Consider the Stokes equations in a sector-like C3 domain Ω R2. It is shown that the Stokes operator generates an analytic semigroup in Lp (Ω) for p 2 [2;1). This includes domains where the Lp-Helmholtz decomposition fails to hold. To show our result we interpolate results of the Stokes semigroup in VMO and L2 by constructing a suitable non-Helmholtz projection to solenoidal spaces