Polydisperse scattering theory and comparisons with data for red blood cells.

Recent results for low-frequency scattering by polydisperse distributions of correlated low-refracting particles averaged over orientation are analyzed numerically. The roles of shape and correlations (parameterized by c) and polydispersity (specified by the normalized variance d in size governed by the gamma probability density) are investigated. The key variable is the net volume fraction w occupied by the particles.

Inversion of ultrasonic scattering data for red blood cell suspensions under different flow conditions.

Recent results for low-frequency scattering by correlated random distributions of nonspherical particles averaged over orientation are applied to invert ultrasonic data for red blood cell suspensions under different flow conditions. The inversion procedure isolates a correlation parameter (c) representing a process in which the volume fraction (w) of particles increases linearly, and also a cell population parameter P. Reduced data records of scattering versus hematocrit are compared with S(c;w)P, where the generalized fluctuation function S is proportional to the variance in particle number, and P is proportional to the backscattering cross section of an isolated particle.

Transparency of pair-correlated, random distributions of small scatterers, with applications to the cornea.

We consider transmission through pair-correlated random distributions of lossless dielectric (globular, cylindrical, or plate-like) scatterers with length parameter a and average spacing small compared to wavelength. Each optical particle is centered in a tough adherent transparent coating whose outer surface (sphere, cylinder, or slab) has radius b smaller than or equal to a. The corresponding attenuation coefficients beta varies directly as WM involve an integral of the appropriate radial-distribution function.

Scattering by two-component random distributions of spheres.

Theory and prototype (at wavelength lambda = 5 mm) partial coherence scattering data for optical applications in diagnostic measurements on two component suspensions or gases are presented. Results are given for equal volume mixtures of two sizes of moving randomly distributed large spheres for all realizable values of the fractional volume w (the fraction of the slab region container filled by scattering material). The relative index of refraction of the spheres was about 1.