Global Stability Results for the Weak Vector Variational Inequality

In this paper, we consider the global stability of solutions of a Weak Vector Variational Inequality in a finite-dimensional Euclidean space. Upper semi-continuity of the solution set mapping is established. And by a scalarization method, we derive a sufficient condition that guarantees the lower semi-continuity of the solution set mapping for the Weak Vector Variational Inequality     

Anomalous thermal expansion of osmium dioxide

The precision lattice parameters of osmium dioxide have been determined at different temperatures, in the temperature range 30–444 °C, using a Unicam high temperature powder camera 19 cm in diameter and CuKα radiation. The data have been used to evaluate the coefficients of thermal expansion at various temperatures by a graphical method. The ‘a’ parameter increases non-linearly with increasing temperature while the ‘c’ parameter remains constant throughout the range of temperature studied indicating a zero coefficient of expansion along the c-direction. The abnormal thermal behaviour of this compound is explained in terms of the electronic configuration of the d-shell of the cation.     

Peculiarities of X-ray diffraction in quartz monocrystals

The scattering of X-rays in quartz monocrystals has been investigated. It has been shown, that, even in thick quartz monocrystals, kinematic scattering takes place and pendular bands appear. It has been demonstrated experimentally that only a diffraction pattern of clearance is obtained in bicrystal quartz interferometers, whereas in tricrystal interferometers moiré patterns are not produced. The beam reflected from one part of the crystal is no longer reflected from the other parts of the same crystal.     

Surface profile measurement of low-frequency vibrating objects using temporal analysis of fringe pattern

A simple and accurate algorithm (phase scanning method) is proposed for 3D surface contouring and dynamic response determination of a vibrating object. A sinusoidal fringe pattern is projected onto a low-frequency vibrating object by a programmable liquid crystal display projector. The fringe patterns are captured by a high-speed CCD camera with a telecentric gauging lens. Phase values are evaluated point by point using phase scanning method. From the phase values of each point on the object, the contour of the specimen at different instants of vibration can be retrieved. In this paper, a small vibrating coin is used to demonstrate the validity of the method and the experimental results are compared with test results on a stationary coin using four-step phase shifting and fast Fourier transform methods. The technique is especially useful in applications where the vibrating object has a complicated shape.     

Quantitative visualization of micro-tube flow using micro-PIV

This paper describes PIV measurements ofthe flow field in a micro round tube with an internal diameter of 100 μm in order to examine micro-scale effects. Since the refractive index of the micro tube almost corresponds to that of water, the inner flow in the tube can be observed clearly. The micro PIV system has been developed using a microscope, a high sensitive CCD camera, a double pulsed Nd:YAG laser and optics. Applying the micro PIV technique to the flow, the velocity distributions with spatial resolution of 1.8 × 1.8 μm were measured even near the wall in the center plane of the round tube. It was found that the velocities near the tube wall were smaller than the theoretical values calculated by using Poiseuille’s law. It is believed that this disparity is due to micro-scale effects such as interference between particles and the wall, friction at the wall, surface tension and so on.