Straight Wedge Research Articles

Straight disclinations near a free surface II. The interaction between wedge disclinations and surface

The pair interaction energy of straight wedge disclinations in semi-infinite media is calculated. On this basis the elastic behaviour of a two-axis wedge disclination dipole is investigated. The forces acting on it near a free surface are defined. It is shown, that interaction between disclinations in half-space depends not only on their mutual disposition but also on the distance from each of them to a free surface. [Russian Text Ignored].

Non-Equilibrium Flow of an Ideal Dissociating Gas Behind an Attached Shock Wave

SummaryThe curvature of an attached shock wave and the flow variable gradients at the tip of a straight edged wedge caused by non-equilibrium effects are determined for a steady plane flow. The specific source of non-equilibrium effects considered here is the dissociation-recombination reaction in a symmetrical diatomic gas. An oxygen like idea dissociating gas is used as an example in calculating the desired quantities. The qualitative behaviour of the exact results is compared with those obtained by using approximate methods.

Diffraction Co-Efficient of a 90° Straight Dielectric Wedge with TM Illumination: A Numerical Method

This paper deals with numerical evaluation of complex diffraction co-efficient for a 90° straight dielectric wedge with TM illumination. Since diffraction co-efficients for dielectric structures are not well defined because of the severe analytical difficulties they pose, this evaluation will help to solve many physical problems untractable before. Computation shows that the diffraction co-efficient is a function of €r σ frequency and is dependent upon the position of the source and the field point.

Straight wedge disclination near a free surface

Straight wedge disclination near a free surface

The non-uniform motion of a thin smooth rigid inclusion through an elastic solid

A two-dimensional example of non-uniform motion by a smooth, relatively thin, symmetric rigid inclusion through an elastic solid is analyzed. Integral solutions to the related boundary-initial value problem are obtained for the case of edge speeds bounded by the dilatational wave speed at large times. The wavefront patterns, including the possibility of Mach waves, are noted. Some attention is focused on the case of the straight wedge, and logarithmic singularities are found at its edge for subsonic speeds.

Supersonic flow past a nearly straight wedge

Supersonic flow past a nearly straight wedge

High-Frequency Flexural Modes of Straight Wedges

A theoretical and experimental study is made of the flexural vibrations of wide wedges that are driven at the base by ferroelectric transducers. The transducers are bonded to the wedges and oriented so that flexural modes of vibration are generated. The wedges have triangular profiles; their width is larger than six wavelengths. The natural frequencies of vibration are first computed using the classical theory, which neglects the effect of rotary inertia. The results are used to check out a computer implementation of the Myklestad-Prohl method. The correspondence is found to be good. A graph is suggested that makes the application of the Mykelstad- Prohl method to harmonics beyond the third easier and more graphic. The effect of rotary inertia on the natural frequencies is then investigated using the Myklestad-Prohl method. This effect is found to be small for the fundamental frequency but rapidly larger for higher harmonics. Graphs of wedge length versus fre- quency are Flotted for the first five harmonics. For several wedges the natural frequencies are measured and compared with the

Temperature stresses due to a heat source located on one side of a straight wedge

A heat source acts on one side of a straight wedge with adiabatic boundaries. The temperature stresses are determined in terms of the displacement potential and Airy stress function.

An automatic recording microdensitometer

The paper describes an automatic recording microdensitometer based on the Dobson splitbeam type of instrument, using a single lamp and single photocell. The shutter is driven at a non-synchronous speed and an electromechanical transducer is used to convert the output to a synchronous frequency. This output is used to operate a servomechanism which moves a straight photographic wedge and also a potentiometer. The output from the potentiometer drives a standard pen recorder. The fim carriage has movements of 28.5 cm and 12.5 cm in perpendicular directions and accurate measurements of these displacements can be read on scales permanently in place.