The applicability of Brillouin scattering to flow field diagnostics

To fill the void between turbulence theory and experiment; particularly in the flow fields consisting of monatomic gases, for example in wind tunnels, means of measuring fluctuating quantities are needed. In the area of density fluctuation measurement, the optical method of Brillouin scattering was suggested. This was based on the theory, that the Brillouin scattered intensity is proportional to a function of density. In this investigation the potential of this method as a diagnostic tool was studied. Here the density fluctuations in gases were sought. Continuous wave lasers and interferometers were used as the primary illuminating source and scattered light filters respectively

Quantitative Ultrasonic Tomographic Imaging

An ultrasonic transmission technique is described which images the velocity variation within metal parts. The arrival time of the first ultrasonic pulse to traverse the object is detected and displayed as a gray scale on a cathode ray tube while the part is being scanned horizontally and vertically. The velocity variation imaged within several cast turbine parts will be shown. The system can detect voids as small as 0.020 inch. With a more complex computer program and knowing the dimensions of the part, tomographic reconstruction of the velocity variation within parts with curved surfaces should be possible

The Complete Retirement Survival Guide : Everything You Need to Know to Safeguard Your Money, Your Health, and Your Independence

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Tracking Wage Inequality Trends with Prices and Different Trade Models: Evidence from Mexico

Mexican wage inequality rose following Mexico's accession to the General Agreement on Tariffs and Trade/World Trade Organization in 1986. Since the mid-1990s, however, wage inequality has been falling. Since most trade models suggest that output prices can affect factor prices, this paper explores the relationship between output prices and wage inequality. The rise of inequality can be explained by the evolution of the relative price of skill-intensive goods relative to unskilled-intensive goods, but these prices flattened by 1999 and thus cannot explain the subsequent decline in wage inequality. An alternative trade model with firm heterogeneity driven by variations in the relative price of tradable relative to non-tradable goods can explain the decline in wage inequality. The paper compares this model's predictions with Mexican inequality statistics using data on output prices, census data, and quarterly household survey data. In spite of the model's simplicity, the model's predictions match Mexican variables reasonably well during the years when wage inequality fell