The role of negative compressibility is considered in detail. Experimental observations of negative bulk modulus in prestrained foam are presented and interpreted. A constrained microscopic model which exhibits negative compressibility is proposed. Some other negative and counterintuitive properties of matter, like negative Poisson’s ratio, negative thermal expansion, negative specific heat, an...

In glass, starting from a dependence of the Angell's fragility on the Poisson ratio [V. N. Novikov and A. P. Sokolov, Nature 431, 961 (2004)], and a dependence of the Poisson ratio on the atomic packing density [G. N. Greaves, A. L. Greer, R. S. Lakes, and T. Rouxel, Nature Mater. 10, 823 (2011)], we propose that the heterogeneities are predominantly density fluctuations in strong glasses (lowe...

1186 Ó WILEY-VCH Verlag GmbH, D-69469 Weinheim, 1999 0935-9648/99/1410-1186 $ 17.50+.50/0 Adv. Mater. 1999, 11, No. 14 quenching to room temperature. As a result, the polarization bandwidth was found to increase by a factor of 2.4 over what was expected of a constant-pitch film. The increased bandwidth was attributed to a pitch gradient resulting from photoinduced racemization of the chiral dop...

Negative Poisson's ratio foam was used in the development of seat cushions which exert reduced peak pressure upon the skin of seated persons. Foam processing techniques were scaled up. A longer processing time was required for cushion size samples in comparison with small samples. Pressure distributions on a seated subject were measured using a pressure-sensitive array. Seated pressure distribu...

Passive broadband detection of target signals by an array of hydrophones in the presence of multiple discrete interferers is analyzed under Gaussian statistics and low signal-to-noise ratio conditions. A nonhomogeneous Poisson-modulated interference process is used to model the ensemble of possible arrival directions of the discrete interferers. Closed-form expressions are derived for the recog...

We consider two-dimensional, two-phase, elastic composites consisting of a soft isotropic medium into which hard elastic inclusions have been placed, requiring that the inclusions be interconnected only at corner points. Denoting by the ratio of Young's modulus for the soft and hard phases, we show that the leading term in the asymptotic expansion as ! 0 for the eeective moduli can be calculate...

In this paper, we present a three-dimensional Poisson equation solver for the electrostatic potential of a charged beam with large longitudinal to transverse aspect ratio in a straight and a bent conducting pipe with open-end boundary conditions. In this solver, we have used a Hermite–Gaussian series to represent the longitudinal spatial dependence of the charge density and the electric potenti...

INTRODUCTION It is very important to review the meaning of the Odds Ratio as a measure of effect and association, as well as, the bias of the Odds Ratio when it is assumed as a risk ratio or a prevalence ratio in the case of frequent disease or frequent health outcome. MATERIAL AND METHODS We simulated in a cohort of 200 individuals with 100 exposed and 100 non-exposed to a risk factor, a fir...

This paper studies triangulations obtained from Poisson disc sampling. The Poisson disc sampling strategy with radius parameter α can be used to obtain a set of points in the interior or on the boundary of a given solid object in the plane. Using this sampling, one can construct a triangulation from its α-complex. In this work we give two contributions: the quality of this triangulation in term...