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Shiv Nadar University

(SoNS) School of Natural Sciences

A sulfur-rich copolymer is synthesized via a sustainable, eco-friendly approach using two major wastes namely, elemental sulfur (industrial waste) and cardanol (agro waste) and its application as cathode active material in Li−S battery. The presence of chemically bound sulfur (90 wt\%) utilising cardanol (10 wt\%) derivative in the copolymer (S90) showed a reduction in the active material dissolution into the electrolyte. In addition, the organic sulfur units get dispersed into the insoluble/insulating Li2S2/Li2S phase and thus found to suppress their irreversible deposition. Li−S battery based on S90/multi-walled carbon nanotubes (MWCNT) (10 wt\%) exhibited a reversible capacity of 1302 mAh g−1 at 2nd cycle, maintaining a high reversible capacity of 928 mAh g−1 after 70 cycles at a relatively constant coulombic efficiency over 99 \% at current rate of 200 mA g−1. At 1000 mA g−1 current rate, the composite cathode delivered a reversible capacity of 697 mAh g−1 at 2nd cycle and retained 75 \% of its initial capacity even after 180 cycles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

World University root node

Chemistry

ChemistrySelect

Cardanol benzoxazine-Sulfur Copolymers for Li-S batteries: Symbiosis of Sustainability and Performance

A 'direct' alkynylation of isatins, which uses potassium tert-butoxide to provide the desired 3-hydroxy-3-ethynyl-2-oxindoles in good to high yields, is reported. This protocol proceeds smoothly for both electron-rich and electron-deficient alkynes in comparable reaction rates and does not require any specially design ligand or expensive transition-metal catalysts.

Synthesis (Germany)

Transition-Metal-Free Terminal Alkyne Addition to Isatins

DnaK or Hsp70 of Escherichia coli is a master regulator of the bacterial proteostasis network. Allosteric communication between the two functional domains of DnaK, the N-terminal nucleotide-binding domain (NBD) and the C-terminal substrate- or peptide-binding domain (SBD) regulate its activity. X-ray crystallography and NMR studies have provided snapshots of distinct conformations of Hsp70 proteins in various physiological states; however, the conformational heterogeneity and dynamics of allostery-driven Hsp70 activity remains underexplored. In this work, we employed single-molecule Förster resonance energy transfer (sm-FRET) measurements to capture distinct intradomain conformational states of a region within the DnaK-SBD known as the lid. Our data conclusively demonstrate prominent conformational heterogeneity of the DnaK lid in ADP-bound states; in contrast, the ATP-bound open conformations are homogeneous. Interestingly, a nonhydrolysable ATP analogue, AMP-PNP, imparts heterogeneity to the lid conformations mimicking the ADP-bound state. The cochaperone DnaJ confers ADP-like heterogeneous lid conformations to DnaK, although the presence of the cochaperone accelerates the substrate-binding rate by a hitherto unknown mechanism. Irrespective of the presence of DnaJ, binding of a peptide substrate to the DnaK-SBD leads to prominent lid closure. Lid closure is only partial upon binding to molten globule-like authentic cellular substrates, probably to accommodate non-native substrate proteins of varied structures. © 2016 Federation of European Biochemical Societies

Life Sciences

FEBS Journal

Monitoring conformational heterogeneity of the lid of DnaK substrate-binding domain during its chaperone cycle

An agro-waste origin cardanol benzoxazine monomer (Ca) has shown potential as a suitable sustainable linker to chemically bind petroleum industry generated waste, elemental sulphur (S) to form random copolymers poly(S-r-Ca). A series of random copolymers with varied weight percent of elemental sulphur (20–95\%) were synthesised via bulk polymerisation methodology. The Ca monomer offered several reaction sites to facilitate the formation of sulphur rich copolymers as supported by FT-IR, 1H NMR, Raman spectroscopy, XRD, DSC and TGA studies. The curing temperature of Ca was found to be lowered to reaction temperature i.e. 185 °C from 242 °C using elemental sulphur as co-reactant. Preliminary studies of random poly(S-r-Ca) copolymers with a very high sulphur loadings (&gt;80\% w/w) demonstrated inverse vulcanisation and suggest their utility as an efficient substitute to elemental sulphur as a cathode material in Li-S battery. © 2016 Elsevier Ltd

Polymer

Cardanol benzoxazines – A sustainable linker for elemental sulphur based copolymers via inverse vulcanisation

The stability of organic photovoltaic (OPV) devices in ambient conditions has been a serious issue which needs to be addressed and resolved timely. In order to probe the degradation mechanism in a donor-acceptor polymer PDPP-TNT: PC71BM bulk heterojunction basedOPVdevices, we have studied current density-voltage ( J-V ) behavior and impedance spectroscopy of fresh and aged devices. The current-voltage characteristic of optimized fresh devices exhibit a short circuit current density ( Jsc) of 8.9 mA cm2, open circuit voltage (Voc) of 0.79 V, fill factor (FF) of 54.6\%, and power conversion efficiency (PCE) of 3.8\%. For aged devices, Jsc,Voc, FF, and PCE were reduced to 57.3\%, 89.8\%, 44.3\% and 23.7\% of its initial value, respectively. The impedance spectra measured under illumination for these devices were successfully fitted using a CPE-based circuit model. For aged devices, the low-frequency response in impedance spectra suggests an accumulation of the photogenerated charge carriers at the interfaces which leads to a significant lowering in fill factor. Such degradation in device performance is attributed to the incorporation of oxygen and water molecules in devices. An increase in the recombination resistance indicates a deterioration of free charge carrier generation and conduction in devices. © 2016 IOP Publishing Ltd.

Physics

Fulltext

Materials Research Express

Analysis of degradation mechanisms in donor-acceptor copolymer based organic photovoltaic devices using impedance spectroscopy

Metals (Zr, Zn and Cu) containing oil swollen surfactant gels have been utilized as precursors for the preparation of metal oxides (ZrO2, ZnO and CuO) nanoparticles. No metal alkoxide, external gelating agent or any other intricate molecule have been utilized to reinforce gelation; gel stage has been achieved simply through judicial adjustment of water to surfactant ratio and salinity of the reaction mixture. Unlike, several previously published reports, in this approach surfactant has been added not to just increase the viscosity of solution but it has also formed rod shaped gelatinous micelles in response to the variation in water to surfactant ratio, which endowed mechanical strength to the gel. The effect of nature of metal salt on mechanical properties of gel has also been investigated. Zn and Cu containing cetyltrimethylammonium bromide (CTAB) gels have been found to be strongest and weakest, respectively. Metal containing CTAB gels were heat treated at various temperatures (600, 700 and 800 °C) in order to obtain metal oxides nanoparticles. The effect of calcination temperature on crystallinity, particle size and morphology of the metal oxides nanoparticles has also been investigated. A comparison between ZrO2 nanoparticles prepared using conventional sol gel and oil swollen surfactant gel method has also been carried out in terms of crystallinity, particle size and optical property. © 2016 Elsevier Ltd and Techna Group S.r.l.

Ceramics International

Oil swollen surfactant gel based synthesis of metal oxides nanoparticles: An attractive alternative for the conventional sol gel synthesis

Recently, Kórus [7] studied the Λ 2-strong convergence of numerical sequences. By using the idea of this paper, we introduce [ Λ 2, F, u, p] -strongly convergent sequence spaces defined by a sequence of modulus functions. We also make an effort to study some inclusion relations, topological and geometric properties of these spaces. Some characterizations for strong convergent sequences are given. Finally, we study statistical convergence over these spaces and problems related to Fourier series. © 2016, Akadémiai Kiadó, Budapest, Hungary.

Mathematics

Acta Mathematica Hungarica

Applications of strongly convergent sequences to Fourier series by means of modulus functions

We carry out a systematic qualitative analysis of the two quadratic schemes of generalized oscillators recently proposed by Quesne [J. Math. Phys. 56, 012903 (2015)]. By performing a local analysis of the governing potentials, we demonstrate that while the first potential admits a pair of equilibrium points one of which is typically a center for both signs of the coupling strength λ, the other points to a centre for λ < 0 but a saddle λ > 0. On the other hand, the second potential reveals only a center for both the signs of λ from a linear stability analysis. We carry out our study by extending Quesne's scheme to include the effects of a linear dissipative term. An important outcome is that we run into a remarkable transition to chaos in the presence of a periodic force term f cos ωt. © 2016 AIP Publishing LLC.

Journal of Mathematical Physics

Qualitative analysis of certain generalized classes of quadratic oscillator systems

The aim of this paper is twofold. Firstly, to define a solution concept of Pareto-optimality for a multi-objective flexible linear programming (MOFLP) problem (or multi-objective fuzzy linear programming problem) and design a method to extract a Pareto-optimal solution of MOFLP problem from the set of optimal solutions of equivalent optimization problem formulated by Dubey and Mehra (2013). Secondly, to extend this study to multi-objective linear programming problem involving hard and flexible constraints with interval uncertainty. A flexible constraint with interval uncertainty generalizes a flexible constraint by allowing preferences to be expressed in the form of intervals. An optimistic-pessimistic approach is proposed to solve multi-objective flexible linear programming with interval uncertainty (MOFLPIU) using an interval-valued fuzzy set representation and the Hurwicz optimism-pessimism criterion. © 2016 - IOS Press and the authors. All rights reserved.

Journal of Intelligent and Fuzzy Systems

Pareto-optimal solutions for multi-objective flexible linear programming

Based on the results of the classification by T.-h. Abe, Nucl. Phys. B894, 374 (2015)., we exhaustively investigate Yukawa sector of U(8) model on magnetized orbifolds T2/Z2, T2/Z3, T2/Z4 and T2/Z6 by evaluating ratios of the mass eigenvalues of the three states in all the possible configurations with one and two Higgs pairs where three generations are realized in fermions. Because of the smearing effect via kinetic mixing, one can realize a hierarchy such as 10-2-10-3, but it is very difficult to achieve the mass ratio between the up and top quarks (mup/mtop∼10-5) on the complicated magnetized orbifolds T2/ZN(N=3,4,6). © 2016 American Physical Society.