Guided ultrasonic waves are frequently used for both structural health monitoring and nondestructive testing of metallic plate-like structures. Signals resulting from waves generated by one or more fixed piezoelectric transducers can be recorded around the periphery of an area of interest using a non-contact approach such as a scanning laser vibrometer. It is desired to determine the location o...

In spectral domain interferometry, the interference signal generated by directly reflected waves from the two surfaces of a sample plate under test is greatly enhanced by the blockage of those light waves reflected by the two arm mirrors in the Michelson interferometer. This sample surface-reflected interference signal, being the optical path length of the plate, is therefore identifiable direc...

in this paper, plate-like nio nanoparticles were prepared by one-pot solid-state thermal decomposition of nickel (ii) schiff base complex as new precursor. first, the nickel (ii) schiff base precursor was prepared by solid-state grinding using nickel (ii) nitrate hexahydrate, ni(no3)2∙6h2o, and the schiff base ligand n,n′-bis-(salicylidene) benzene-1,4-diamine) for 30 min without using any solv...

This paper analyzes the edge-reflection problem of obliquely incident guided waves in a plate. The generalized guided-wave theories in a plate, including the orthogonality of modes and the mode-decomposition method are summarized. The edge-reflection problem is solved on the basis of the mode-decomposition method. Some numerical results are presented and compared to experimental results. [doi:1...

We predict that the interface of materials with defocusing thermal nonlinearities supports stable fundamental and higher-order surface waves when the opposite edges of the medium are maintained at different temperatures. Such surface waves exist due to the interplay between repulsion from the interface and the defocusing thermal nonlinearity that deflects light beams from the bulk of the medium...

Protoplanetary disks are mainly heated by radiation from the central star. Since the incident stellar flux at any radius is sensitive to the disk structure near that location, an unstable feedback may be present. Previous investigations show that the disk would be stable to finite-amplitude temperature perturbations if the vertical height of optical surface is everywhere directly proportional t...

We address ring-shaped surface waves supported by defocusing thermal media with circular cross-section. Such waves exist because of the balance between repulsion from the interface and deflection of light from the bulk medium due to defocusing nonlocal nonlinearity. The properties of such surface waves are determined by the geometry of the sample. Nodeless ring surface waves are stable for all ...

Fluctuations in the crack tip structure should result in the release of elastic waves that propagate both into the bulk as well as along the surface. Ramanathan and Fisher (1997), and Morrisey and Rice (1998) examined such wave interactions in a series of increasingly sophisticated models. The possibility that in-plane and out-of-plane perturbations could persist along the crack surface, result...

For high end heat exchanging applications in cryogenics and space application, compactness and effectiveness are the key factors which determine the performance of heat exchanger. Matrix heat exchanger with perforated plate heat surfaces has both criterions to suit into these applications. High thermal conductivity plate and low thermal conductivity spacers are stacked together to obtain low lo...

We demonstrate the experimental realization of a multiresonant metamaterial for Lamb waves, i.e., elastic waves propagating in plates. The metamaterial effect comes from the resonances of long aluminum rods that are attached to an aluminum plate. Using time-dependent measurements, we experimentally prove that this metamaterial exhibits wide band gaps as well as sub- and suprawavelength modes fo...