484 research outputs found
Aperiodic nano-photonic design
The photon scattering properties of aperiodic nano-scale dielectric
structures can be tailored to closely match a desired response by using
adaptive algorithms for device design. We show that broken symmetry of
aperiodic designs provides access to device functions not available to
conventional periodic photonic crystal structures.Comment: 23 pages, LaTex, 8 postscript figure
From Golden Spirals to Constant Slope Surfaces
In this paper, we find all constant slope surfaces in the Euclidean 3-space,
namely those surfaces for which the position vector of a point of the surface
makes constant angle with the normal at the surface in that point. These
surfaces could be thought as the bi-dimensional analogue of the generalized
helices. Some pictures are drawn by using the parametric equations we found.Comment: 11 pages, 8 figure
Reconfiguration for Modular Robots Using Kinodynamic Motion Planning
This paper presents computational and experimental evi-dence that it is possible to plan and execute dynamic motions that involve chain reconfiguration for modular reconfigurable robots in the presence of obstacles. At the heart of the approach is the use of a sampling-based motion planner that is tightly integrated with a physics-based dynamic simulator. To evaluate the method, the planner is used to compute motions for a chain robot con-structed from CKbot modules to perform a reconfiguration, at-taching more modules and continuing a dynamic motion while avoiding obstacles. These motions are then executed on hard-ware and compared with the ones predicted by the planner
Analysis of entropy generation in natural convection of nanofluid inside a square cavity having hot solid block: Tiwari and Das' model
A computational work has been performed in this study to investigate the effects of solid isothermal partition insertion in a nanofluid filled cavity that is cooled via corner isothermal cooler. Mathematical model formulated in dimensionless primitive variables has been solved by finite volume method. The study is performed for different geometrical ratio of solid inserted block and corner isothermal cooler, Rayleigh number and solid volume fraction parameter of nanoparticles. It is observed that an insertion of nanoparticles leads to enhancement of heat transfer and attenuation of convective flow inside the cavity
Chaos in Andreev Billiards
A new type of classical billiard - the Andreev billiard - is investigated
using the tangent map technique. Andreev billiards consist of a normal region
surrounded by a superconducting region. In contrast with previously studied
billiards, Andreev billiards are integrable in zero magnetic field, {\it
regardless of their shape}. A magnetic field renders chaotic motion in a
generically shaped billiard, which is demonstrated for the Bunimovich stadium
by examination of both Poincar\'e sections and Lyapunov exponents. The issue of
the feasibility of certain experimental realizations is addressed.Comment: ReVTeX3.0, 4 pages, 3 figures appended as postscript file (uuencoded
with uufiles
MHD thermogravitational convection and thermal radiation of a micropolar nanoliquid in a porous chamber
This work studies the thermogravitational transmission and thermal radiation of micropolar nanoliquid within
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