Simulation techniques for predicting current and voltage distribution across electrode surface and electrolyte

Journal of Solid State Electrochemistry - One of the prerequisites in all electrochemical processes is to achieve uniform distribution in potential and current across the electrodes and the cell....     

Spectral Measures for <Emphasis Type="Italic">G</Emphasis><Subscript>2</Subscript>

Spectral measures provide invariants for braided subfactors via fusion modules. In this paper we study joint spectral measures associated to the rank two Lie group G ₂, including the McKay graphs for the irreducible representations of G ₂ and its maximal torus, and fusion modules associated to all known G ₂ modular invariants.     

Influence of the Molecular Character and Degree of Crosslinking on the Interaction of Crosslinked Polyacrylamide-Supported Amines with Cu(Ii) Ions

Abstract

Amino groups were incorporated into polyacrylamides with 2?20 mol% of crosslinking agents by transamidation with ethylenediamine. Divinylbenzene, N,Nv′-methylene-bis-acrylamide, and tetraethyleneglycol diacrylate were used as the crosslinking agents. The complexation of these resins, which contain ligand functions in different macromolecular structural environments, was investigated with Cu(II) ions. The Cu(II) uptake of these different resins was correlated with the molecular character and degree of crosslinking in the polymer matrix. The time course and kinetics of complexation depend on the nature of the crosslinking agent in the polymer matrix. The swelling behavior of the uncomplexed and complexed resins, structural characteristics, and thermal decomposition behavior were followed by IR, EPR, and thermal analysis. The swelling characteristics of the complexed resins are lower than those of the uncomplexed resins. Complexation resulted in shifting of the IR absorptions. The EPR parameters depend on the nature of crosslinking and are in agreement with the distorted tetragonal geometry of the Cu(II) complexes. The thermal decomposition behavior also depends on the nature and the degree of crosslinking in the polymer matrix.     

Antifungal activity of silver nanoparticle-encapsulated β-cyclodextrin against human opportunistic pathogens

Silver nanoparticles were synthesised by reducing silver acetate with a long-chain aliphatic amine. β-Cyclodextrin (CD)-stabilised silver nanoparticles were successfully synthesised and characterised by the UV–vis spectroscopy and scanning electron microscopy analysis. This system was examined for their antifungal activity against opportunistic human pathogens such as Aspergillus fumigatus, Mucor ramosissimus and Chrysosporium species. This study clearly demonstrates that the present system is a powerful antifungal agent against human opportunistic pathogenic fungi.     

Synthesis,characterisation and antibacterial applications of water-soluble,silver nanoparticle-encapsulated β-cyclodextrin

This paper describes a simple method for the synthesis of water-soluble, silver nanoparticle-encapsulated β-cyclodextrin by phase transfer of silver nanoparticles from organic to aqueous phase using β-cyclodextrin as a capping agent. β-Cyclodextrin–silver nanoparticle inclusion complex was purified, characterised by spectroscopic and microscopic analyses and tested in vitro against Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Escherichia coli and Klebsiella pneumoniae. The silver nanoparticle-encapsulated β-cyclodextrin inclusion complex displayed considerable antimicrobial activity and stability.

     

Bromine Complexes of Polyvinylpyrrolidone Supports: A Mild Reagent for the Transformation of α‐Oxoketene Dithioacetals to β‐Oxothiolesters

When α‐oxoketene dithioacetals 1a–n were treated with the bromine complex of a copolymer of 1‐vinyl‐2‐pyrrolidone and 4‐vinylpyridine, the corresponding thiolcarboxylates 2a–n were formed in excellent yields. The reaction also works with other 1‐vinyl‐2‐pyrrolidone‐derived polymers as well as commercially available polyvinylpyrrolidone–bromine complexes. The method is suitable for preparing aliphatic, aromatic, and γ,δ‐unsaturated β‐oxothiolcarboxylates.     

Spectrophotometric Determination of Hydrogen Peroxide Using Leucocrystal Violet in Micellar Medium

A simple and sensitive spectrophotometric method for the determination of hydrogen peroxide, based on the increase in color intensity of dye on addition of surfactant, is described. Hydrogen peroxide is first reacted with potassium iodide in acidic medium, in presence of ammonium molybdate to liberate iodine. The liberated iodine oxidizes leucocrystal violet to crystal violet having maximum absorbance at 593 nm. The color of the dye intensifies with the addition of the surfactant, cetyl pyridinium chloride though the absorption maximum remains the same. Beer's law is obeyed in the range 0.05–0.45 µg of hydrogen peroxide per 25 mL of final solution (0.002–0.018 µg mL^?1) with an excellent correlation coefficient (r = 0.9977). The proposed method has been successfully applied for the analysis of hydrogen peroxide in various food products and rainwater.     

Characterization of uranium isotopic abundances in depleted uranium metal assay standard 115

Certified reference material (CRM) 115, Uranium (Depleted) Metal (Uranium Assay Standard), was analyzed using a TRITON Thermal Ionization Mass Spectrometer to characterize the uranium isotope-amount ratios. The certified ²³⁵U/²³⁸U “major” isotope-amount ratio of 0.0020337 (12) in CRM 115 was determined using the total evaporation (TE) and the modified total evaporation (MTE) analytical techniques. In the MTE method, the total evaporation process is interrupted on a regular basis to allow correction of background from peak tailing, internal calibration of the secondary electron multiplier detector versus the Faraday cups, peak-centering, and ion source re-focusing. For the “minor” ²³⁴U/²³⁸U and ²³⁶U/²³⁸U isotope-amount ratio measurements using MTE, precision and accuracy comparable to conventional analyses are achieved, without compromising the quality of the ²³⁵U/²³⁸U isotope-amount ratios. Characterized values of the ²³⁴U/²³⁸U and ²³⁶U/²³⁸U isotope-amount ratios in CRM 115 are 0.000007545 (10) and 0.000032213 (84), respectively. The ²³³U/²³⁸U isotope-amount ratio in CRM 115 is estimated to be <5 × 10^?9. The homogeneity of the CRM 115 materials is established through the absence of any statistically significant unit-to-unit variation in the uranium isotope-amount ratios. The measurements leading to the certification of uranium isotope-amount ratios are discussed.     

Synthesis and cytotoxicity study of pyrazoline derivatives of methoxy substituted naphthyl chalcones

2-Acetyl naphthalene reacts with various methoxy substituted benzaldehyde in the presence of 10 % sodium hydroxide solution giving functionalized chalcones. The synthesized chalcones when further reacted with hydrazine hydrate in the presence of acetic acid afforded N-acetyl pyrazolines. All the synthesized products were confirmed by various spectral data such as FTIR, ¹H NMR, ¹³C NMR, and HRMS studies. All the synthesized compounds were screened for cytotoxicity against various cell lines.     

Surface morphological and impedance spectroscopic studies on the interaction of polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) with mild steel in acid solutions

The inhibition of mild steel corrosion in aerated acid mixture of 0.5 N H₂SO₄ and 0.5 N HCl solution was investigated using potentiodynamic polarization studies, linear polarization studies, electrochemical impedance spectroscopy, adsorption, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, degree of surface coverage, adsorption kinetics, and surface morphology is investigated. The inhibition efficiency increased markedly with increase in additive concentration. The presence of PEG and PVP decreases the double-layer capacitance and increases the charge-transfer resistance. The inhibitor molecules first adsorb on the metal surface following a Langmuir adsorption isotherm. Both PEG and PVP offer good inhibition properties for mild steel and act as mixed-type inhibitors. Surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that PVP offers better protection than PEG.