It is shown that the free motion of any three-dimensional rigid body colliding elastically between two parallel, at walls is equivalent to a three-dimensional billiard system. Depending upon the inertial parameters of the problem, the billiard system may possess a potential energy eld and a non-Euclidean connguration space. The corresponding curvilinear motion of the billiard ball does not nece...

X-Shaped ternary five-block molecules, composed of a rigid p-terphenyl core, two terminal glycerol groups and two flexible n-alkyl or semiperfluorinated chains fixed laterally to opposite sides of the terphenyl moiety, form liquid crystalline phases built up of honeycomb-like arrays of polygonal cylinders, where the rod-like aromatic cores form cylinder walls with a thickness equal to the width...

A direction-length framework is a pair (G, p), where G = (V ;D,L) is a ‘mixed’ graph whose edges are labeled as ‘direction’ or ‘length’ edges, and p is a map from V to R for some d. The label of an edge uv represents a direction or length constraint between p(u) and p(v). Let G be obtained from G by adding, for each length edge e of G, a direction edge with the same end vertices as e. We show t...

A severe case of stenosis in coronary arteries results in turbulence in the blood flow which may lead to the formation or progression of atherosclerosis. This study investigated the turbulent blood flow in a coronary artery with rigid walls, as well as 80% single and double stenoses on blood flow. A finite element-based software package, ADINA 8.8, was employed to model the blood flow. The hemo...

During mating, yeast cells must perforate their rigid cell walls at the right place to allow cell-cell fusion. In this issue, Dudin et al. (2015; J. Cell Biol. http://dx.doi.org/jcb.201411124) image mating fission yeast cells with unprecedented spatiotemporal resolution. The authors find that when mating cells come into contact, they form aster-like actin structures that direct cell wall remode...

I. Preliminary Remarks A. Introduction B. Some Fundamental Definitions and Questions C. Basic Scenarios for Friction D. Phenomenology of Static and Low-Velocity Kinetic Friction II. Rigid Walls A. Geometric Interlocking B. Thermal Effects C. Applications 1. Nanotubes 2. Curved, Nanoscale Contacts III. Dry, Elastic Friction A. Properties of the Prandtl–Tomlinson Model 1. Definition of the Model ...

We present a system for rendering planar rigid-body motion by means of a redundant parallel mechanism. The device design, the control architecture and the passive virtual environment simulation are presented. The system is used to compare various virtual walls and friction models proposed for haptic applications. In addition, the reset-integrator dry friction model proposed by Haessig and Fried...

A simple thermal oxidation-etching process was developed to translate vertical silicon nanowire arrays into silica nanotube arrays. The obtained nanotubes perfectly retain the orientation of original silicon nanowire arrays. The inner tube diameter ranges from 10 to 200 nm. High-temperature oxidation produces relative thick, rigid, and pinhole-free walls that are made of condensed silica. This ...

Simulations describing the settling of suspensions of solid particles bounded by a rigid container are presented. Results are compared with previous simulations of homogeneous suspensions with periodic boundary conditions. Velocity fluctuations in vertically inhomogeneous suspensions are found to saturate under conditions similar to those found in laboratory experiments, while in vertically hom...

We theoretically study field-induced domain wall motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Domain walls can propagate along a dissipationless wire through spin wave emission locked into the known soliton velocity at low fields. In the presence of damping, the usual Walker rigid-body propagation mode can become unstable for a magnetic field smaller t...