The distribution of the ratio of consecutive level spacings in random matrix ensembles

We derive expressions for the probability distribution of the ratio of two consecutive level spacings for the classical ensembles of random matrices. This ratio distribution was recently introduced to study spectral properties of many-body problems, as, contrary to the standard level spacing distributions, it does not depend on the local density of states. Our Wigner-like surmises are shown to be very accurate when compared to numerics and exact calculations in the large matrix size limit. Quantitative improvements are found through a polynomial expansion. Examples from a quantum many-body lattice model and from zeros of the Riemann zeta function are presented.Comment: 5 pages, 4 figure

Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

of laminated beams

In this study, an analytical solution procedure for elastic-plastic stress analysis of laminated beams is presented. The Bernoulli-Euler theory was used in the solution considering infinitesimal small deformations. A finite element analysis was also carried out, by using LUSAS 13.4, to compare and verify results obtained by analytical solution. Several stacking sequences such as [0 degrees/90 degrees]s, [90 degrees/0 degrees]s, [15 degrees/-15 degrees]s, [30 degrees/-30 degrees]s, and [45 degrees/-45 degrees]s are chosen for comparison

Elastic-plastic stress analysis and expansion of plastic zone in clamped and simply supported aluminum metal-matrix laminated plates

An elastic-plastic stress analysis and the expansion of plastic zone in layers of stainless steel fiber-reinforced aluminum metal-matrix laminated plates are studied by using Finite Element Method and First-order shear deformation theory for small deformations. The plate is meshed into 64 elements and 289 nodes with simply supported or clamped boundary conditions. Laminated plates of constant thickness are formed by stacking four layers bonded symmetrically or antisymmetrically. It is assumed that the laminated plates are subjected to transverse uniform loads. Loading is gradually increased from yield point of the plate as 0.0001 MPa at each load step. Load steps are chosen as 100, 150 and 200. (C) 2000 Elsevier Science Ltd. All rights reserved

Stacking sequence effects on elastic-plastic stress variation in composite plates with clamped edges

This paper deals with stacking sequence effects on stress variation in steel fibre reinforced aluminium metal-matrix composite plates prepared by squeeze casting process. By such an analysis, it is intended to form an opinion about elastic-plastic stress variation in laminated plates used in engineering applications associated with structural designs. Load carrying capacities of laminated composite plates for various stacking sequences are examined. Elastic/plastic and residual stress variations correspond to arbitrary lay-ups are given by means of figures. Laminated composite plates are assumed to be clamped at all edges. The finite element method is applied for such an analysis considering shear deformation effects and small plastic deformations. For the nonlinear solution of the problem, a combined incremental/iterative procedure (modified Newton-Raphson) is used. Mechanical properties of an orthotropic layer are obtained experimentally

Material nonlinear behavior of laminated metal-matrix composite plates supported at edges under uniform traverse loading

This paper deals with material non-linear behavior of steel fiber reinforced aluminum metal-matrix composite plates prepared by the squeeze casting process. By such an analysis it is intended to form an opinion about elastic-plastic behavior of laminated plates used in engineering problems associated with structural designs. Therefore, loads that begin plastic flow at any point of laminate for various stacking sequences are obtained. Afterwards, how further increase in loads gradually causes spreading of plastic zone is examined. Elastic/plastic and residual stress variations correspond to diverse stacking sequences of laminated plates are illustrated in figures. Plastic zone expansions are displayed in simply supported symmetric and antisymmetric laminated composite plates by contour plots. The finite element method is applied for analyses based on small deformation effects including shear deformation. For nonlinear solution of the problem a combined incremental/iterative procedure (modified Newton-Raphson) is followed and load increments are chosen to be sufficiently small to obtain a rapid-converged equilibrium state. Mechanical properties of an orthotropic layer are obtained experimentally. (C) 2002 Elsevier Science Ltd. All rights reserved