Dynamical patterns in clapping behavior.

A nonlinear dynamics framework that has been applied successfully to several laboratory idealizations of rhythmic behaviors was applied to a more naturally occurring behavior, clapping. Inertial loading of limbs and frequency of oscillation were manipulated. Displacement of relative phase from perfectly in phase and the variability of relative phase, both of which are used as indexes of coordination dynamics, increased with greater inertial imbalance between limbs. Increasing frequency exaggerated these effects. These hallmark properties of coupled oscillator dynamics appeared whether or not the hands contacted, albeit with the latter condition revealing a significant asymmetry in the dynamics. Results highlight the generality of the coupled oscillator regime in interlimb coordination as well as its appropriateness for characterizing behaviors that involve contact of limb surfaces and suggest one way in which perceptual information may tune the dynamical regime. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective laser sintering II. Sintering multilayer refractory composites

Processes are considered in the selective laser sintering of multilayer composites based on TiN’MTiB₂ refractory powder mixtures, hard-alloy material of TN20 type, and a steel substrate. Selectivity of the process, which is expressed in the behavior of the multilayer composite material in sintering regimes that differ in laser power input, is demonstrated. At low power input, the layers of refractory alloys shirnk appreciably mainly because of capillary infiltration of the liquid from the hard-alloy layer, which lies beneath it. At high power, the consolidation of the refractory mixture is due mainly to the formation of an eutectic.