Abstract: A method for acoustically examining a route includes sensing passively excited residual sounds of a vehicle system during travel over a route, examining the passively excited residual sounds to identify one or more changes of interest in the passively excited residual sounds, and identifying a section of the route as being damaged responsive to the one or more changes of interest in the passively excited residual sounds that are identified.

Abstract: A nondestructive evaluation method is described for ultrasonic evaluation and detection of features in polycrystalline materials, such as grain orientation (e.g. texturing) or grain boundary orientation. The method may, for example, be employed to detect diffusion bonds that contain undesirable planar grain boundary arrays. The method utilizes time of flight statistics gathered from reflections associated with incident ultrasonic signals directed into a plurality of locations within the material.

Abstract: A method for suppressing sampling-ring artifacts produced by spiral-scan-based 2D selective excitation pulses, such as a those exciting a `pencil-shaped` region, employs a 2D annular saturation pulse followed by a gradient `crusher` lobe which dephases the transverse magnetization in the annular region. The annular saturation pulse is itself based on a spiral k-space trajectory having a limited number of cycles and a small outer radius, and is designed to saturate magnetization of tissue of the subject corresponding to the artifact rings of an excitation region while not affecting a central region. The annular saturation pulse may also be reshaped to limit the peak RF power to levels currently used for clinical MR imaging, while preserving bandwidth and the 2D excitation profile.