A differential equation of a Riccati type for the diffuse reflection coefficient of a stratified sea is proposed. For a homogeneous sea with arbitrary inherent optical properties this equation is solved analytically. For an inhomogeneous sea it is solved approximately for any arbitrary stratification. The resulting equation expresses the diffuse reflection coefficient of the sea through vertica...

This paper presents a novel model-based method for in-situ estimation of sound reflection coefficients in acoustic enclosures. The method uses a modeling engine for simulation of acoustic propagation and generation of the spatial pseudospectrum using a beamforming technique. The simulated pseudospectrum is matched with the measured pseudospectrum acquired by a real beamforming microphone array ...

An approximation technique is considered for computing transmission and reflection coefficients for plane waves propagating through stratified slabs. The propagation of elastic pulse through a planar slab is derived from first principles using straightforward time-dependent method. The paper ends with calculations of enhancement factor for the elastic plane wave and it is shown that it depends ...

Various problems concerning the effects of the boundaries of the ocean on the propagation of pressure waves In the ocean are considered. The propagation of a transient pressure wave In a wedge shaped region of fluid Is treated. This Is the model chosen to describe the situation In which an underwater explosion takes place In a coastal ocean region which Is characterized by a strongly sloping bo...

in this paper, a novel directional super wide band micro strip antenna based on a simple and new geometry has been proposed. the antenna exhibits the widest bandwidth ever reported to the authors’ knowledge from 50 ghz to 200 ghz. its radiation pattern is approximately steady in the frequency ranges of 50 ghz to 200 ghz. the antenna consists of a club-like radiating patch, a combination of thre...

Offset continuation (OC) is the operator that transforms common-offset seismic reflection data from one offset to another. Earlier papers by the first author presented a partial differential equation in midpoint and offset to achieve this transformation. The equation was derived from the kinematics of the continuation process with no reference to amplitudes. We present here a proof that the sol...

a r t i c l e i n f o The purpose of this study is to investigate the role of filling materials (e.g., quartz sand and kaolin clay) in the interaction between a P-wave and a rock fracture. The specific fracture stiffness reflects the seismic response of a filled fracture, while the wave transmission coefficient describes P-wave transmission across the filled fracture. A series of experimental t...

This paper deals with a new formulation for the diffraction of a plane wave by a periodic grating. As a simple example, the diffraction of a transverse magnetic wave by a perfectly conductive periodic array of rectangular grooves is discussed. On the basis of a shadow hypothesis such that no diffraction takes place and only the reflection occurs with the reflection coefficient −1 at a low grazi...

A Lamb wave-based crack detection method for aluminum plates health monitoring is developed in this paper. Piezoelectric disks are employed to actuate and capture the Lamb wave signals. The position of crack is assumed to be aligned with the sensor and actuator.  Extraction of high quality experimental results of lamb wave propagation in a plate-like structure is considerably complicated due to...

Solid-state bonding methods, e.g., diffusion bonding and pressure welding, are becoming common manufacture and repair techniques for gas turbine engine components. Effective NDE inspection techniques are crucial to the utilization of this approach due to the high stresses on the bond plane associated with jet engine operation. Recently we have examined ultrasonic techniques for assessing bond q...