Multi-scale modeling of double network hydrogels

A double network hydrogel (DN gel) is a class of elastomeric gels formed by polyelectrolyte and neutral polymer networks. The DN gel is the toughest material among the conventional hydrogels. It shows inelastic features such as necking instability [1] and the stress softening [2], similar to that one known in elastomers. In this contribution, we purpose a micro-mechanically motivated model to characterize relation between internal damage and inelastic deformations in the DN gel. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the chlorenium source in the asymmetric chlorolactonization reaction

N-Acylated N-chlorohydantoins are shown to be competent chlorenium sources in the (DHQD)(2)PHAL-mediated asymmetric chlorolactonization. The derivatives demonstrate the exact role of the N1 and N3 chlorine atoms in the parent dichlorohydantoins with the N1 chlorine serving as an inductive activator and the N3 chlorine being delivered to the substrate. The putative associated catalyst/chlorine source complex was experimentally demonstrated through a series of matched/mismatched experiments employing chiral N-chlorinated hydantoins.     

Solving a novel multiobjective placement problem of recloser and distributed generation sources in simultaneous mode by improved harmony search algorithm

This article deals with optimal placement of Distributed Generation (DG) sources and recloser in simultaneous mode and develops an improved harmony search (iHS) algorithm to solve it. For this, two important control parameters have been adjusted to reach better solution from simple HS algorithm to obtain better solution from simple HS algorithm. The proposed multiobjective function consists of two parts; first is improving reliability indices and second is minimizing power loss. The reliability indices have been selected based on satisfactory requirements of costumer and electric company as well as response to transient and permanent faults. Then, four reliability indices has been used in objective function; that is, system average interruption duration index (SAIDI), cost of energy not supplied, momentary average interruption frequency index, and system average interruption frequency index (SAIFI). Simulation has been performed on a practical distribution network in North West of Iran. Three scenarios have been introduced; that is, scenario (i) First, placement of DGs, and then recloser, scenario (ii) First, placement of recloser, and then DG, and scenario (iii) simultaneous placement of DG and recloser. Also, three cases are defined based on the number of used DG and recloser. Results of the proposed algorithm have been compared with related values of particle swarm optimization and simple HS algorithms. The core contribution of the presented study is introducing several novel indices to analyze and discuss the obtained results from simulation. © 2014 Wiley Periodicals, Inc. Complexity 21: 328–339, 2015     

Simple flat Leavitt path algebras are von Neumann regular

For a unital ring, it is an open question whether flatness of simple modules implies all modules are flat and thus the ring is von Neumann regular. The question was raised by Ramamurthi over 40?years ago who called such rings SF-rings (i.e. simple modules are flat). In this note we show that an SF Steinberg algebra of an ample Hausdorff groupoid, graded by an ordered group, has an aperiodic unit space. For graph groupoids, this implies that the graphs are acyclic. Combining with the Abrams–Rangaswamy Theorem, it follows that SF Leavitt path algebras are regular, answering Ramamurthi’s question in positive for the class of Leavitt path algebras.     

A sensitive opto-fluidic biosensor based on plasmonic-graphene/black phosphorous configuration for detection of hemoglobin concentrations

Optical Review - In this paper, a sensitive Opto-fluidic biosensor for detection of Hemoglobin concentrations in blood samples is proposed and considered. The proposed system is based on the...     

A network evolution model for the anisotropic Mullins effect

In this contribution, a micro-mechanical constitutive model for filled rubberlike materials is proposed. Rubber network is decomposed into two parts, elastic rubber network and polymer-filler network. As a consequence of filler contribution, the last one is subjected to damage. A non-Gaussian strain energy function for a single chain with a constant valence angle has been postulated. Damage in different directions is governed by the corresponding maximal micro-stretch and is considered as a result of network evolution. Directional network rearrangement as a consequence of network evolution has been employed in order to describe induced anisotropy and permanent set. The model shows good agreement with experimental data on uniaxial tension tests in two orthogonal directions. (© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)