earthquake ground-motions show significant variability in both spectral and temporal characteristics. procedures to generalize and predict strong ground motions may be generally divided into three main disciplines: numerical techniques based on a kinematic source description, empirical attenuation models, and semi-empirical stochastic models. numerous studies have shown that, in the near-fault ...

In a recent work, the beamsteering characteristics of parametric loudspeakers were validated in an experiment. It was shown that based on the product directivity model, the locations and amplitudes of the mainlobe and grating lobes could be predicted within acceptable errors. However, the measured amplitudes of sidelobes have not been able to match the theoretical results accurately. In this pa...

On 18 May 2009, an Mw 4.6 earthquake occurred beneath Inglewood, California, and was widely felt. Though source mechanism and its location suggest that the Newport–Inglewood fault (NIF) may be involved in generating the earthquake, rupture directivity must be modeled to establish the connection between the fault and the earthquake. We first invert for the event’s source mechanism and depth with...

Linear and planar antenna arrays are synthesized to have maximum directivity for a specified sidelobe level. The directivity is maximized subject to a given SLL. The beamwidth and the zeros of array factor are studied as well as the directivity. Maximum directivity-arrays are compared through some examples with super-directive, uniform, Dolph-Chebyshev and Riblet-Chebychev arrays to find a comp...

A technique to incorporate directivity in the Pseudospectral time-domain method (PSTD) for auralization purposes is presented. The Pseudospectral time-domain method is a numerical method for solving the wave equation that requires only two spatial points per wavelength, making it more efficient compared to other wave based methods. The effect of source directivity as well as the head-related di...

We tested the hypothesis that increased pulse wave reflection and altered backward waveform morphology contribute to increased pulse pressure in subjects with higher pulse pressure compared with lower pulse pressure and to actions of vasoactive drugs to increase pulse pressure. We examined the relationship of backward to forward wave morphology in 158 subjects who were evaluated for hypertensio...

A line-focus ultrasonic SH-wave probe is developed for possible application to TOFD method. The probe is composed of a quarteror half-cylindrical wedge and a piezoelectric transducer adhered to the cylindrical surface of the wedge. An SH-wave pulse with cylindrical wave front is generated by the transducer, transmitted to the wedge, and focused on a line at the bottom surface of the wedge. Henc...

In this paper, a new kind of end-fire array was built by employing high directivity plate end-fire antenna as the basic element based on electromagnetic surface wave theory. Being different from normal end-fire array, in the new array, high directivity plate endfire antenna elements were arranged end to end along the end-fire direction, and the interelement spacing and uniform progressive phase...

A stu~$~ o/the acoustic backxatteringproduced by m army of scattering spheresfixed to ajishing net is reported. The System enhances net detection and also allows net identijcation by using a method in which the echogram is arranged to resemble a commercial bar-code. A simplijied theoretical model has been developed to shrdy the inlerference due to echo formation. This model establishes the rela...