Packing problems have long been a topic of interest. Traditionally, efforts had been focused on Euclidean space, but as interest in hyperbolic space has grown, many of the Euclidean problems have been translated into the hyperbolic arena, in which the problems are almost always vastly more complicated. The particular packing problem of interest here is a hyperbolic version of packing congruent ...

BACKGROUND Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS A cylindrical type traveling wave ultrasonic motor usin...

In this paper, considering symmetric collapse mode for hybrid tubes, and using Tsai-Hill fracture criterion to take into account the off-axis strength of an orthotropic lamina, an analytical model is extended and an expression is derived for mean crushing load and fold lengths of circular hybrid tubes. In this model, the influences of the geometrical dimensions including diameter, thickness of ...

Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N -slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators...

A Zener±Stroh crack is formed by coalescing a dislocation pileup and therefore is a net dislocation loaded crack. In this paper, the interaction between a Zener±Stroch crack and surrounding cylindrical ®bers in a ®ber-reinforced composite material has been investigated. The crack is located in the matrix and near a ®ber, while the in ̄uence of other ®bers on the crack is considered through the t...

‘THEUSE of heavy aluminum foil in our ashing procedure for PB1 (1), introduced 3 years ago, has proved extremely successful in preventing cross-contamination. A Temco double-door muffle furnace is used for which three steel buckets were made; small buckets, 4 in. wide, 6 in. long, and 6 in. deep, and one large bucket, 6 in. wide, 8 in. long, and 6 in. deep. A steel shovel was made to aid the te...

Many organs are composed of branched networks of epithelial tubes that transport vital fluids or gases. The proper size and shape of tubes are crucial for their transport function, but the molecular processes that govern tube size and shape are not well understood. Here we show that three genes required for tracheal tube morphogenesis in Drosophila melanogaster encode proteins involved in the s...

The process of freezing of water and blockage of pipes are summarized. Current research on freezing and its applications are briefly reviewed. Design concepts are introduced for doing work by utilizing pressures caused by ice blockage. Several conceptual designs are presented for experimental setups for the isostatic pressurization of thin walled tubes. Potential practical uses of pressures gen...

Core-shell composite structures are potential candidates for Li-ion battery electrodes as they can take advantage of materials with higher energy density and materials with higher cyclability. This paper derives an analytical solution for isotropic 1-dimensional diffusion with galvanostatic boundary condition in composite slab, cylinder and sphere using separation of variables method. A general...