653 research outputs found
Universal router concept
Portable universal router can cut holes of large diameter and irregular shapes, machine recesses, and drill holes with certain edge-distance limitations. Rectangular and round holes may be cut without a template
Variable-speed, portable routing skate
Lightweight, portable, variable-speed routing skate is used on heavy metal subassemblies which are impractical to move to a stationary machine. The assembly, consisting of the housing with rollers, router, and driving mechanism with transmission, weighs about forty pounds. Both speed and depth of cut are adjustable
Weakly Nonlinear Theory of Pattern-Forming Systems with Spontaneously Broken Isotropy
Quasi two-dimensional pattern forming systems with spontaneously broken
isotropy represent a novel symmetry class, that is experimentally accessible in
electroconvection of homeotropically aligned liquid crystals. We present a
weakly nonlinear analysis leading to amplitude equations which couple the
short-wavelength patterning mode with the Goldstone mode resulting from the
broken isotropy. The new coefficients in these equations are calculated from
the hydrodynamics. Simulations exhibit a new type of spatio-temporal chaos at
onset. The results are compared with experiments.Comment: 4 pages, RevTeX, 4 PS-figures, to appear in PR
Entropy Change through Rayleigh-B\'enard Convective Transition with Rigid Boundaries
The previous investigation on Rayleigh-B\'enard convection of a dilute
classical gas [T. Kita: J. Phys. Soc. Jpn. {\bf 75} (2006) 124005] is extended
to calculate entropy change of the convective transition with the rigid
boundaries. We obtain results qualitatively similar to those of the stress-free
boundaries. Above the critical Rayleigh number, the roll convection is realized
among possible steady states with periodic structures, carrying the highest
entropy as a function of macroscopic mechanical variables.Comment: 5 pages, 4 figure
Numerical study of domain coarsening in anisotropic stripe patterns
We study the coarsening of two-dimensional smectic polycrystals characterized
by grains of oblique stripes with only two possible orientations. For this
purpose, an anisotropic Swift-Hohenberg equation is solved. For quenches close
enough to the onset of stripe formation, the average domain size increases with
time as . Further from onset, anisotropic pinning forces similar to
Peierls stresses in solid crystals slow down defects, and growth becomes
anisotropic. In a wide range of quench depths, dislocation arrays remain mobile
and dislocation density roughly decays as , while chevron boundaries
are totally pinned. We discuss some agreements and disagreements found with
recent experimental results on the coarsening of anisotropic electroconvection
patterns.Comment: 8 pages, 11 figures. Phys. Rev E, to appea
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