We present a non-linear elastic model of a coherent transition with discontinuous volume change in an isotropic solid. The model reproduces the anomalous thermodynamics typical of coherent equilibrium including intrinsic hysteresis (for a pressure driven experiment) and a negative bulk modulus. The novelty of the model is that the statistical mechanics solution can be easily worked out. We find...

Cubic (space group: Fmm) iridium phosphide, Ir2P, has been synthesized at high pressure and high temperature. Angle-dispersive synchrotron X-ray diffraction measurements on Ir2P powder using a diamond-anvil cell at room temperature and high pressures (up to 40.6 GPa) yielded a bulk modulus of B0 = 306(6) GPa and its pressure derivative B0' = 6.4(5). Such a high bulk modulus attributed to the sh...

Considerable interest has been devoted to the development of various classes of acoustic metamaterials that can control the propagation of acoustical wave energy through these materials. However, all the currently exerted efforts are focused on studying passive metamaterials with fixed material properties. In this article, the emphasis is placed on the development of a new class of composite ac...

Using the laser-heated diamond anvil cell, we investigate the stability and equation of state of the postperovskite (ppv, CaIrO(3)-type) phase synthesized from a natural pyroxene composition with 9 mol.% FeSiO(3). Our measured pressure-volume data from 12-106 GPa for the ppv phase yield a bulk modulus of 219(5) GPa and a zero-pressure volume of 164.9(6) A(3) when K'(0) = 4. The bulk modulus of ...

X-ray diffraction and ultrasonic measurements have been carried out simultaneously up to 7 GPa at ambient temperature on a polycrystalline sample of Fe64Ni36 Invar alloy. The bulk modulus is found to increase linearly with pressure with an unusual low value (1.4) of dB/dP up to about 3.1(2) GPa followed by a regular slope (3.6) at higher pressure. The observation of these two distinct regimes i...

2014 The effect of correlations and ferromagnetic order on the bulk modulus K of the 3d metals is discussed using a second order perturbation treatment of the correlation. For elements in the middle of the series with a low density of states n(EF) at the Fermi level, ferromagnetic order, if possible, acts together with correlation to reduce K. The ferromagnetic elements Fe, Co and Ni lie toward...

We present an alternative derivation of upper-bounds for the bulk modulus of both two-dimensional and three-dimensional cellular materials. For two-dimensional materials, we recover exactly the expression of the Hashin-Shtrikman (HS) upper-bound in the low-density limit, while for three-dimensional materials we even improve the HS bound. Furthermore, we establish necessary and sufficient condit...

Figure 4 4) Constant force on the plunger that automatically depresses when the epidural needle enters the epidural space eliminates the subjective “feel” required with standard LOR syringes. 5) Air Vs Saline: As no subjective feel is required, technically saline is as good as air. Thus by avoiding air complications related to it like, patchy block, risk of venous air embolism can be avoided. 6...