Accurate first-derivative nonadiabatic couplings for the H3 system

A conical intersection exists between the ground (1 2 A[prime]) and the first-excited (2 2A[prime]) electronic potential energy surfaces (PESs) of the H3 system for C3v geometries. This intersection induces a geometric phase effect, an important factor in accurate quantum mechanical reactive scattering calculations, which at low energies can be performed using the ground PES only, together with appropriate nuclear motion boundary conditions. At higher energies, however, such calculations require the inclusion of both the 1 2A[prime] and 2 2A[prime] electronic PESs and the corresponding nuclear derivative couplings. Here we present ab initio first-derivative couplings for these states obtained by analytic gradient techniques and a fit to these results. We also present a fit to the corresponding 1 2A[prime] and 2 2A[prime] adiabatic electronic PESs, obtained from the ab initio electronic energies. The first-derivative couplings are compared with their approximate analytical counterparts obtained by Varandas et al. [J. Chem. Phys. 86, 6258 (1987)] using the double many-body expansion method. As expected, the latter are accurate close to conical intersection configurations but not elsewhere. We also present the contour integrals of the ab initio couplings along closed loops around the above-mentioned conical intersection, which contain information about possible interactions between the 2 2A[prime] and 3 2A[prime] states

Wind loads on Y plan shape tall building

An experimental study was carried out on the models of lsquoYrsquo plan shape tall building in an open circuit wind tunnel to investigate the wind loads generated on the building in isolated as well as interference condition. The base shear (Fx), overturning moment (My) and torsional moment (Mz) acting on the instrumented model were measured. For the isolated condition, the measurements were made for many wind incidence angles. For studying the interference effects, two similar building models were placed in side-by-side configuration and tandem configuration and the spacing between these models were varied. It is observed that the wind incidence angle greatly affects the wind induced loads on the lsquoYrsquo plan shaped building. Depending on the position of the interfering building, the interfence effects may either be beneficial or may have an adverse effect

The sedges and grasses of district Saharanpur (U.P.), India

The communication represents the study of sedges and grasses, which is the result of extensive survey and exploration of sedges and grasses of Saharanpur district form the period of January 2008 to December 2011. A total number of 110 species of Cyperaceae and Gramineae (Poaceae) have been collected from this area. Out of 110 species of these two families belonging to 64 genera, 77 species belong to Gramineae (Poaceae) and 33 species belong to Cyperaceae

A Peridynamics-Based Micromechanical Modeling Approach for Random Heterogeneous Structural Materials

This paper presents a peridynamics-based micromechanical analysis framework that can efficiently handle material failure for random heterogeneous structural materials. In contrast to conventional continuum-based approaches, this method can handle discontinuities such as fracture without requiring supplemental mathematical relations. The framework presented here generates representative unit cells based on microstructural information on the material and assigns distinct material behavior to the constituent phases in the random heterogenous microstructures. The framework incorporates spontaneous failure initiation/propagation based on the critical stretch criterion in peridynamics and predicts effective constitutive response of the material. The current framework is applied to a metallic particulate-reinforced cementitious composite. The simulated mechanical responses show excellent match with experimental observations signifying efficacy of the peridynamics-based micromechanical framework for heterogenous composites. Thus, the multiscale peridynamics-based framework can efficiently facilitate microstructure guided material design for a large class of inclusion-modified random heterogenous materials