General mixed mode I/II fracture criterion for wood considering T-stress effects

A general mixed mode I/II fracture criterion applicable to orthotropic materials with arbitrary oriented cracks with respect to the orthotropy axes is presented. Wasted energy in fracture process zone is considered based on the calculated damage properties for an elastic solid containing random distributed micro-cracks. This new criterion includes the effects of T-stress as a significant term in fracture of some specimens. The correctness and applicability of this criterion has been investigated for some wood specimens. Very good agreement is obtained from verification of results with experimental data.     

Preparation and characterization of P4MVPMnO4/SBA-15 as an efficient heterogeneous oxidant: An organic–inorganic hybrid polymer

This work is concerned about the preparation and characterization of MnO₄⁻ supported poly (4-methyl vinylpyridinium)/SBA-15 which was effectively employed as a heterogeneous oxidant for oxidation of aromatic alcohols. P4MVPMnO₄/SBA-15 exhibited excellent activity and selectivity under mild and solvent-less conditions.     

A computationally efficient method of evaluating Green's functionsfor 1-, 2-, and 3-D enclosures

A model-based parameter estimation (MBPE) technique is used to evaluate efficiently the Green's functions associated with parallel plates, rectangular waveguides, and cavities. The numerical model uses a novel approach to break the dyadic Green's function into simpler functions so that a set of regressed polynomials can reconstruct the function. Examples of method of moments calculations incorporating MBPE are presented to show the computational advantage as compared to the direct approach     

A multilevel formulation of the method of moments [EM scattering]

The modeling of electromagnetic scattering and radiation problems using the method of moments (MoM) is limited to resonant frequencies because of the extensive computational requirements of solving large matrix equations. In this study, a multilevel formulation of MoM which allows substantial computational savings and, thus, extends the application of MoM to higher frequencies is presented. Using a hierarchy of discretization levels, the multilevel technique extracts different modal components of the solution by focusing on a specific portion of the spectrum of the solution at a given level. The fundamental features of this process for the MoM solution of the electric field integral equation (EFIE) are developed and implemented. This multilevel MoM allows the rapid evaluation of the current distributions on a variety of 2-D scatterers with thousands of unknowns in fewer than ten cycles and in fractions of the normal CPU times. The method is stable, fast, suitable for multiple excitations, and adaptable as a `solve' module for almost any MoM code     

Synthesis of undoped and Fe nanoparticles doped SnO<Subscript>2</Subscript> nanostructure: study of structural,optical and electrocatalytic properties

In this study, undoped and nano Fe doped SnO₂ nanostructures were synthesized by hydrothermal method. Characterization of the synthesized nanostructures was performed by X-ray diffraction and scanning electron microscopy. For investigation of optical properties, photo luminescence and UV–Vis spectrum were taken. The electrochemical response of the carbon paste electrode modified with synthesized nanostructures toward levodopa (L-Dopa) was studied. Cyclic voltammetry studies using prepared modified electrodes showed outstanding electrocatalytic properties towards electro-oxidation of L-Dopa and a significant reduction was observed in anodic over voltage compared to the bare electrode. Obtained results indicated the effective role of the employed dopant. Best response in terms of the current enhancement, overvoltage reduction, and reversibility improvement of the L-Dopa oxidation reaction under experimental conditions was obtained by modified electrode with Fe doped SnO₂ nanoparticles.