Measurements of radiation characteristics of fused quartz containing bubbles.

We report experimental measurement of radiation characteristics of fused quartz containing bubbles over the spectral region from 1.67 to 3.5 microm.

Solidification Processes of Solutions.

Recent progress in modeling pure liquid and dendritic alloy solidification is reviewed to lay the groundwork for freezing of solutions relevant to cryopreservation of biological materials. The classical Stefan problem of freezing/melting a pure substance is discussed first to introduce some of the fundamental concepts, and then the framework for modeling the freezing of solutions is reviewed. The formalism is extended to the freezing of a solution-saturated porous media.

Spectral remote sensing of temperature distribution in semitransparent solids heated by an external radiation source.

A spectral remote sensing method for recovering the temperature distribution in semitransparent solids from remotely sensed spectral emission data is studied. An analytical model that relates the emerging spectral intensity from a plane layer of solid heated by an external radiation source to the temperature distribution, spectral radiation properties, radiation characteristics of the interfaces of the solid, and the source is formulated. The temperature profile is expressed in the form of a finite series of Legendre polynomials; and the coefficients are obtained using an optimization scheme that, by iteratively solving the expressions for emerging intensity, reconstructs the distribution that best fits the spectral emission data.

Estimating the refractive error in optical measurements of transport phenomena.

Approximate methods for calculating the error introduced by the deflection of the light beam or refractive error in schlieren, shadowgraph, interferometric, and holographic measurements of transport phenomena are investigated. Relative error is reported for the well-known correction parabola and paraxial approximations as well as for a new first-order approximation in both a linear and nonlinear refractive index field. The first-order approximation is exact in a linear field but is in about the same error as the other approximations in the nonlinear field of a boundary layer.