Acoustic metamaterials utilizing periodic deep subwavelength resonators can attain negative acoustic properties unavailable in nature. We have developed a negative acoustic index metamaterial for water that combines Helmholtz and rod-spring resonators to control effective bulk modulus and mass density, respectively. Effective properties extracted from full-wave simulations of our metamaterial s...

Rigorous cross-property bounds that connect the effective thermal conductivity k. (or the electrical conductivity a.) and the effective bulk modulus K. of any isotropic, two-phase composite were recently derived by the authors. Here we reformulate these bounds and apply them to porous rocks with dry or fluid-filled pores. It is shown that knowledge of the effective conductivity can yield sharp ...

This paper studies the addition of fibers from end-of-life tires to commercial mortar mixtures. Two different types of mortar, one lime-plastic and other cement-fluid, are mixed with different percentage of fibers ranging from 0% to 1%. The changes in bulk density, consistency, compressive and flexural strength, dynamic Young modulus and water absorption are studied. According to the results, c...

This paper describes a method for calculating the elastic constant of tissue. Length measurements obtained from Ultrasonograms (US) are different from the results obtained from Computerized Tomograms (CT) when the velocity of sound is compared to standardized water measurements. The density of tissue PI can be approximated by the equation. p, = 1N</N,;•. where N, and N". are the CTvalues of tis...

New velocity data in addition to literature data derived from sonic log, seismic, and laboratory measurements are analyzed for elastic silicate rocks. These data demonstrate simple systematic relationships between compressional and shear wave velocities. For water-saturated elastic silicate rocks, shear wave velocity is approximately linearly related to compressional wave velocity and the compr...

Porous polypropylene (PP) is commonly used as separator materials for lithium ion batteries (LIB). Its mechanical properties, especially critical for abuse tolerance and durability of LIB, are subject to change in different environments. To capture the mechanical responses of a porous PP separator, its microstructure was mapped into separate atomistic models of bulk crystalline phases and orien...

We propose a mechanism for stabilizing the size of the extra dimension in the Randall-Sundrum scenario. The potential for the modulus field that sets the size of the fifth dimension is generated by a bulk scalar with quartic interactions localized on the two 3-branes. The minimum of this potential yields a compactification scale that solves the hierarchy problem without fine tuning of parameter...

The effect of a negative bulk modulus phase in elastic composites is studied. Negative bulk modulus K<0 is shown to be possible in selected unit cells. In isotropic solids, K<0 can be attained when negative Poisson’s ratio is sufficiently small, below the stability limit (for stress control) 1⁄4 1. Such materials, if used as inclusions, are predicted to be stable with respect to the band format...