title: Polydisperse scattering theory and comparisons with data for red blood cells.
abstract: 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. The incoherent scattering is determined by delta = PS(c,d;w) with P as a particle population factor that is independent of w, and S as the fluctuation-correlation function of w. Earlier applications of monodisperse (d = 0) theory emphasized the influence of c on the peak delta = delta and its location w = w in order to invert ultrasonic scattering data of Shung and his associates for red blood cell suspensions under different flow conditions. For d greater than 0, comparable curves for delta (w) decrease more gradually with w increasing past w (because of additional scattering arising from polydispersity) and thereby provide better fits to data for the more controlled flows over broader ranges of hematocrit.
authors.affiliation: Mathematics Department, University of Illinois, Chicago 60680.
authors.forename: N E
authors.initials: NE
authors.lastname: Berger
authors.forename: R J
authors.initials: RJ
authors.lastname: Lucas
authors.forename: V
authors.initials: V
authors.lastname: Twersky
mesh_terms: D000162:Acoustics; D055592:Biophysical Phenomena; D001703:Biophysics; D004912:Erythrocytes / Q000502:physiology*; D016018:Least-Squares Analysis; D008954:Models, Biological