Natural polymer-based electrolytes for electrochemical devices: a review

Polymer electrolytes are an important component of many electrochemical devices. Researchers have carried out a significant work for the development of polymer electrolytes. This paper reviews the recent developments in the area of polymer electrolytes using aqueous and nonaqueous-based natural polymers for developing a cheaper, ecofriendly, biodegradable, and widely used electrolytes as a substitute for existing synthetic polymer electrolytes. This paper also encompasses the merits and demerits of the different natural polymers used by the researcher. There is a scope to develop a nonaqueous-based natural polymer electrolyte as an alternate for synthetic polymer electrolyte for batteries and other electronic devices.     

Abkühlungscharakteristik einer gut wärmeleitenden Platte,die bei der Bewegung durch ein Fluid gestreckt wird

Zusammenfassung Das Abkühlungsverhalten einer gut wärmeleitenden Platte, die durch ein Fluid bewegt und dabei nach einem beliebigen Potenzgesetz gestreckt wird, wurde untersucht. Der Impulstransport wird dabei durch eine Gleichung beschrieben, die der Falkner-Skan-Gleichung mit einem Parameter für die Dehnung ähnelt. Für das thermische Problem wurden bezüglich des Ortes ähnliche Lösungen gefunden, die sowohl für kleine als auch große Werte des Fließabstandes gültig sind. Die Konvergenz der Reihen für kleine-Werte konnte durch die Euler-Transformation verbessert werden, so daß die Ergebnisse für alle-Werte Gültigkeit haben.

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The cooling of a low heat resistance stretching sheet moving through a fluid

The cooling characteristics of a low-heat-resistance sheet moving through a fluid have been studied for arbitrary power law stretching. The momentum transfer is governed by an equation that resembles the Falkner-Skan equation with stretching as a parameter. For the thermal problem, locally similar solutions have been obtained for small and large values of the streamwise distance. The convergence of low series has been improved by Euler transformation to yield results valid for all values of.

     

Single-Pot Synthesis of Spiroannulated Dihydrofurans by Iodine–Ammonium Acetate–Mediated Reaction of Dimedone with Aldehydes

Iodine–ammonium acetate–mediated annealation of dimedone with aldehydes led to facile formation of spirodihydrofuran in good yields through tandem Knoevenagel–Michael iodonation and cyclodehydroiodonation reactions in a single pot.     

Pressure effect on structural,electronic and thermodynamic investigations of europium filled skutterudite EuFe4Sb12: LDA and LSDA approximations

Numerical calculations based on the full potential muffin-tin orbitals method (FP-LMTO) within the local density approximation (LDA) and the local spin-density approximation (LSDA) to investigate the structural, electronic and thermodynamic properties of filled skutterudite EuFe₄Sb₁₂ are presented. The electronic band structure and density of states profiles prove that this material is a conductor. The present investigation is also extended to the elastic constants, such as the bulk modulus B, anisotropy factor A, shear modulus G, young's modulus E, Poisson's ratio ν, and the B/G ratio with pressure in the range of 0–40 GPa. The sound velocities and Debye temperatures are also predicted from the above constants. The variations of the primitive cell volume, expansion coefficient α, bulk modulus B, heat capacity (C_p and C_v), Debye temperature θ_D, Helmholtz free energy A, Gibbs free energy G, entropy S, and internal energy U with pressure and temperature in the range 0–3000 K are calculated successfully.     

Electrochemical removal of the hazardous dye Reactofix Red 3 BFN from industrial effluents

The electrochemical treatment of dyestuff from aqueous solution using an iron cell was achieved with reduction in chemical oxygen demand (COD) and color with high efficiency. Degradation of the azo dye Reactofix Red 3 BFN was carried out under different experimental conditions. Electrolysis completely decolorizes the effluent with substantial reduction in COD value. The rate kinetics during electrolysis was found to be first order. Results show that electrochemical reduction is a superior technology for treatment of dyes, as there is no simultaneous addition of anions, such as sulfate or chloride.     

DFT Study of the BH4− Hydrolysis on Au(111) Surface

The mechanism of the catalytic hydrolysis of BH₄⁻ on Au(111) as studied by DFT is reported. The results are compared to the analogous process on Ag(111) that was recently reported. It is found that the borohydride species are adsorbed stronger on the Au⁰-NP surface than on the Ag⁰-NP surface. The electron affinity of the Au is larger than that of Ag. The results indicate that only two steps of hydrolysis are happening on the Au(111) surface and the reaction mechanism differs significantly from that on the Ag(111) surface. These remarkable results were experimentally verified. Upon hydrolysis, only three hydrogens of BH₄⁻ are transferred to the Au surface, not all four, and H₂ generation is enhanced in the presence of surface H atoms. Thus, it is proposed that the BH₄⁻ hydrolysis and reduction mechanisms catalyzed by M⁰-NPs depend considerably on the nature of the metal.     

Kinetics and mechanism of oxidation of phosphorus oxyacids by pyridinium hydrobromide perbromide

Oxidation of three lower oxyacids of phosphorus, viz. phosphinic, phenylphosphinic and phosphorous acids by pyridinium hydrobromide perbromide (PHPB), is first-order with respect to both oxyacid and PHPB. There is no effect on addition of acylonitrile and pyridinium bromide. On oxidation, deuterated phosphinic and phosphorous acids exhibit substantial kinetic isotope effects. The effect of solvent composition on reaction rate indicates that the transition state is more polar than the reactants. Reaction rates were determined at different temperatures and the activation parameters calculated. Alternative mechanisms, involving the two tautomeric forms of the oxyacid, have been formulated and it has been concluded that the reaction proceeds through the pentacoordinated tautomer. Transfer of a hydride ion from the oxyacid to PHPB, in the rate-determining step, has been proposed.     

Evaluation of CSC Charcoal for Production of Dry Combustion Plasma

Evaluation of CSC charcoal by standard thermoanalytical techniques shows that the dry material contains ⪞ 99% carbon having calorific value of about 16.32 mJ/kg; its hydrogen and ash contents are insignificant. On admixture with small amount of K₂CO₃ (seed for generation of combustion plasma) its combustion characteristics remain more or less unaltered though the combustion rates are greatly enhanced. This revised version was published online in July 2006 with corrections to the Cover Date.