This paper reports the outcome of applying two di erent low-Reynolds-number eddy-viscosity models to resolve the complex three-dimensional motion that arises in turbulent ows in ducts with 90◦ bends. For the modelling of turbulence, the Launder and Sharma low-Re k– model and a recently produced variant of the cubic non-linear low-Re k– model have been employed. In this paper, developing turbule...

The problem of how we perceive the shape of an object in space is complicated by the optical fact that to a particular retinal form there does not correspond a unique physical form but a whole set of possible physical forms. A given sheaf of light rays whose cross section is a particular form may be reflected from any surface whose margins coincide with the margins of the sheaf of rays; the sur...

An 11.4 GHz photonic band-gap (PBG) structure where the rods in the inner row have an elliptical cross-section has been designed at MIT and manufactured and tested at high power and high repetition rate at SLAC. This structure exhibits lower surface magnetic fields on the rods relative to previous PBG structures tested at SLAC, which reduces the ohmic heating of the rod surface in an effort to ...

We use a mixed 3-dimensional variational principle to derive 2-dimensional equations for an anisotropic plate-like piezoelectric body and one-dimensional equations for an anisotropic beam-like piezoelectric body. The formulation accounts for double forces without moments which may change the thickness of the plate and deform the cross-section of the rod. The dependence of the bending rigidities...

This paper deals with the measurement of AC corona inception voltage, Vincp, at the tip of a rod electrode using a hemispherically-capped rod-plane electrode configuration for various rod radii with a short air gap. Effects of atmospheric pressure and temperature variation on Vincp are investigated experimentally. An empirical equation for the field form factors of the hemispherically cappe...

The in,nitesimal rigidity (or brie-y rigidity) of a bar-and-joint framework (in any dimension) can be formulated as a rank condition of the so-called rigidity matrix. If there are n joints in the framework then the size of this matrix is O(n), so the time complexity of determining its rank is O(n). But in special cases we can work with graph and matroid theoretical models from which very fast a...

In this chapter, we take a different approach. In Section 2, we analyze the basics of analog subtractive synthesis, using the simple patch of a square-wave oscillator processed by a low-pass filter with a dynamically variable cutoff frequency. In Section 3, we show how a single mathematical function can model both the oscillator and filter together, and describe an efficient formation for this ...