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Postmenopausal osteoporosis in women is characterized by an increase in bone fragility and risk of fracture. In addition to transmenopausal decline in three-dimensional trabecular bone architecture, changes in intrinsic material properties (local stiffness, damping, and hardness) may contribute to increased bone fragility. In this study, nanoindentation was(More)
Radiative transfer and multiple scattering of diffuse ultrasound" (1994). Faculty Publications from the Department of Engineering Mechanics. Paper 6. A model is presented for the mtltiply scattered incoherent field in a continuous polycrystalline elastic medium. Unlike a previous, development based upon energy conservation considerations [J.] for a medium(More)
Diffuse ultrasonic backscatter measurements have been especially useful for extracting microstructural information and for detecting flaws in materials. Accurate interpretation of experimental data requires robust scattering models. Quantitative ultrasonic scattering models include components of transducer beam patterns as well as microstructural scattering(More)
Elastic wave propagation and scattering in heterogeneous, anisotropic media: Textured polycrystalline materials" (1999). Faculty Publications from Nebraska Center for Materials and Nanoscience. Paper 60. The propagation of elastic waves through heterogeneous, anisotropic media is considered. Appropriate ensemble averaging of the elastic wave equation leads(More)
The scattering of elastic waves in heterogeneous media is discussed. Explicit expressions are derived for the attenuation of longitudinal and transverse elastic waves in terms of the statistics of the density and Lamé parameter fluctuations. The derivation is based upon diagrammatic methods with the problem posed in terms of the Dyson equation. The Dyson(More)
Plant development results from controlled cell divisions, structural modifications, and reorganizations of the cell wall. Thereby, regulation of cell wall behaviour takes place at multiple length scales involving compositional and architectural aspects in addition to various developmental and/or environmental factors. The physical properties of the primary(More)
A radiative transfer equation is used to model the diffuse multiple scattering of ultrasound in a medium containing discrete random scatterers. An assumption of uncorrelated phases allows one to write an equation of energy balance for the diffuse intensity. This ultrasonic radiative transfer equation contains single-scattering and propagation parameters(More)
Time dependence of multiply scattered diffuse ultrasound in polycrystalline media" (1995). Time domain results are presented for the multiply scattered longitudinal intensity backscattered from a polycrystalline medium. The results are solutions to the ultrasonic radiative transfer equation (URTE), the derivation of which is based upon radiative transfer(More)
The need for tissue-engineered constructs as replacement tissue continues to grow as the average age of the world's population increases. However, additional research is required before the efficient production of laboratory-created tissue can be realized. The multitude of parameters that affect cell growth and proliferation is particularly daunting(More)