By analogy with the electromagnetic wave, the acoustic transparency phenomenon is analyzed for a multilayered sphere with acoustic metamaterials. The neutral-inclusion concept is used to predict the transparency conditions in the quasistatic case, which are further confirmed by a full-wave analysis. The mechanism of the transparency is based on lowering the total-scattering cross section of the...

Heat loss of 27 full-face motorcycle helmets was studied using a thermal manikin headform. The headform was electrically heated and positioned at the exit of a wind tunnel, so that the air stream flowed onto its front side. All helmets were measured in three sessions in which all the vents were opened or closed consecutively in random order. Average heat loss was calculated from a steady state ...

The horizontal displacement of the soil at face subway tunnel is symmetrically distributed along central axis tunnel, which larger in middle and smaller both sides. related to size excavation face. If area too great, will be large, easily leading collapse. For this reason, builders often use core-keeping ring-cut method build tunnels. A large section divided into several small sections reduce c...

We investigate the effect of image processing techniques when applied as a pre-processing step to three methods of face recognition: the direct correlation method, the eigenface method and fisherface method. Effectiveness is evaluated by comparing false acceptance rates, false rejection rates and equal error rates calculated from over 250,000 verification operations on a large test set of facia...

Abstract This work addresses the determination of yield surfaces for geometrically exact elastoplastic rods. Use is made a formulation where rod subjected to an uniform strain field along its arc length, thereby reducing problem full just cross-section. By integrating plastic and stresses over rod’s cross-section, one then obtains discrete points surface in terms stress resultants. Eventually, ...

Using the full wave approach, the quasi specular contributors to the scattered fields from the large scale surface roughness as well as the Bragg-like diffusely scattered fields from the small scale surface roughness are accounted for in a unified self-consistent manner. Thus the full wave computer codes for the scattering cross sections contain ground truth data only. It has been shown how the...