Scattering reduction of an acoustically hard cylinder covered with layered pentamode metamaterials.

Transformational acoustics offers the theoretical possibility of cloaking obstacles within fluids, provided metamaterials having continuously varying bulk moduli and densities can be found or constructed. Realistically, materials with the proper, continuously varying anisotropies do not presently exist. However, discretely layered cloaks having constant material parameters within each layer may be a viable alternative in practice.

Fluid-structure effects of cloaking a submerged spherical shell.

Backscattering from a cloaked submerged spherical shell is analyzed in the low, mid, and high frequency regimes. Complex poles of the scattered pressure amplitudes using Cauchy residue theory are evaluated in an effort to explain dominant features of the scattered pressure and how they are affected by the introduction of a cloak. The methodology used is similar to that performed by Sammelmann and Hackman [J.

Three-dimensional transport imaging for the spatially resolved determination of carrier diffusion length in bulk materials.

A contact-free optical technique is developed to enable a spatially resolved measurement of minority carrier diffusion length and the associated mobility-lifetime (μτ) product in bulk semiconductor materials. A scanning electron microscope is used in combination with an internal optical microscope and imaging charge-coupled device (CCD) to image the bulk luminescence from minority carrier recombination associated with one-dimensional excess carrier generation. Using a Green's function to model steady-state minority carrier diffusion in a three-dimensional half space, non-linear least squares analysis is then applied to extract values of carrier diffusion length and surface recombination velocity.

Acoustic cloaking using layered pentamode materials.

While receiving less attention in the literature than electromagnetic cloaking, theoretical efforts to define and create acoustic cloaks based upon mimicking coordinate transformations through use of metamaterials is of interest. The present work extends recent analysis of Norris [Proc. R.

Computer assisted age progression.

A computer assisted method for altering the perceived age of a human face is presented. Our technique is based on calculating a trajectory or axis within a multi-dimensional space that captures the changes in large scale facial structure, shading and complexion associated with aging. Fine facial details associated with increasing age, such as wrinkles, are added to the aged face using a variation on a standard image processing technique called high boost filtering.