Abstract We answer a question of Ciliberto’s about cylinders in rational surfaces obtained by blowing up the plane at points general position. Bibliography: 13 titles.

A modeling study was conducted to determine the conditions under which fluidlike zooplankton of the same volume but different shapes (spherical/cylindrical) have similar or dramatically different scattering properties. Models of sound scattering by weakly scattering spheres and cylinders of finite length used in this analysis were either taken from other papers or derived and herein adapted for...

Composites of concentric cylinders can fail by microcracks that span the thickness and length of one cylinder but arrest at the boundary to adjacent cylinders. This failure mode was analyzed by developing a new polar shear-lag analysis for stresses in a cross section of a concentric-cylinder composite. The analysis can accurately calculate stresses in each cylinder in the presence of microcrack...

Parallel robots exhibit high stiffness, low weight and low dynamic forces, mostly because of the closed loop chains implied by their structure, and allow the positioning of the actuators on the truss. These characteristics outline the possibility of actuating such kind of robotic devices by means of pneumatic actuators. The position control of pneumatic cylinders through proportional valves sat...

Equilibria of a nematic liquid crystal confined between two eccentric cylinders are studied within a purely director approach. A planar equilibrium configuration competes against a three-dimensional one. A stability diagram is obtained in terms of both the ratio between the radii of the bounding cylinders and the distance between their axes. It turns out that the nonplanar minimizer has a struc...

Efficient numerical methods for analyzing photonic crystals (PhCs) can be developed using the Dirichlet-to-Neumann (DtN) maps of the unit cells. The DtN map is an operator that takes the wave field on the boundary of a unit cell to its normal derivative. In frequency domain calculations for band structures and transmission spectra of finite PhCs, the DtN maps allow us to reduce the computation ...

The acoustic transmission loss of a finite periodic array of long rigid cylinders, without and with porous absorbent covering, is studied both theoretically and in the laboratory. A multiple scattering model is extended to allow for the covering and its acoustical properties are described by a single parameter semi-empirical model. Data from laboratory measurements and numerical results are fou...