On the polarography of zinc in ethylenediamine medium

Polarography of zinc in ethylenediamine medium has been carried out. The equilibrium potentials have been determined by amalgam polarography. The standard rate constant for the electrode reaction and the stability constants of the complexes have been calculated.     

Indirect polarographic determination of stability constants

The stability constants of cadmium thiosulphate complexes have been determined in 25% methanol medium. The stability constants of thiosulphate complexes of zinc and lanthanum have been determined by the indirect method using cadmium as the indicator ion.     

Effect of complexing agents on the disproportionation of uranium (V)

The effect of lactate, thiocyanate, sulphate, oxalic acid and fluoride on the disproportionation of uranium (V) formed at the dropping mercury electrode has been studied. The rate constants for the disproportionation reaction are calculated and the results are discussed on the basis of the stability of the complexes.     

Electron impact induced hydrogen migrations in organic molecules: IV—novel hydrogen transfers in alkyl o-methoxybenzoates

Simultaneous hydrogen transfers—one from the methoxy group and the other from the alkyl group—to both the oxygen atoms of the ester function result in the formation of a common ion at m/z 152 in the alkyl o-methoxybenzoates on electron impact. Expulsion of the formyl radical from this ion leads to a fragment resembling the protonated benzoic acid. Another novel feature in these compounds is the loss of H₂O from the [M? R]⁺ ion which arises through an ortho effect during a secondary fragmentation process.     

Spectrum of density fluctuations in a particlefluid system—II. Polydisperse spheres

This paper presents an extension of the analysis shown in Part I to a polydisperse particle-fluid system. The density autocorrelation is shown to be a function of two quantities, a generalized Overlap function for which an analytical expression is derived, and the radial distribution function (RDF). In Fourier transform space, the density spectrum again appears to be a strong function of the mean particle size, and secondarily the mean particle separation distance. One unusual result is previously observed oscillations in the density spectrum of a monodisperse system of particles are severely dampened or even eliminated in the polydisperse case, depending on the width of the particle size distribution. Apparently contributions from different particle correlations interfere with each other, thereby reducing the coherent oscillations seen in the monodisperse particle-fluid system. Furthermore at large wavenumbers, the spectrum decays with a −2 power-law, independent of the shape of the particle size distribution. This behavior can be traced to the Overlap function which controls the behavior of the spectrum beyond the first peak. Remarkably the −2 power-law spectrum is determined by the shape of the particles (i.e. spheres) rather than their spatial distribution (RDF).

The effect of an asymptotically large pressure gradient on the correlation of several important higher-order moments is revisited for the polydisperse system. The relatively simple relationships developed for the monodisperse system are lost in the polydisperse case because particles of different sizes will be influenced differently by an applied pressure gradient. The result is moments that are of different order in velocity can no longer be related to each other (as they were in the monodisperse system), even in this idealized flow. A more comprehensive understanding of this phenomenon can only be achieved through direct numerical simulation or experiment.     

Flame propagation of nano/micron-sized aluminum particles and ice (ALICE) mixtures

Flame propagation of aluminum–ice (ALICE) mixtures is studied theoretically and experimentally. Both a mono distribution of nano aluminum particles and a bimodal distribution of nano- and micron-sized aluminum particles are considered over a pressure range of 1–10 MPa. A multi-zone theoretical framework is established to predict the burning rate and temperature distribution by solving the energy equation in each zone and matching the temperature and heat flux at the interfacial boundaries. The burning rates are measured experimentally by burning aluminum–ice strands in a constant-volume vessel. For stoichiometric ALICE mixtures with 80 nm particles, the burning rate shows a pressure dependence of r_b = aPⁿ, with an exponent of 0.33. If a portion of 80 nm particles is replaced with 5 and 20 μm particles, the burning rate is not significantly affected for a loading density up to 15–25% and decreases significantly beyond this value. The flame thickness of a bimodal-particle mixture is greater than its counterpart of a mono-dispersed particle mixture. The theoretical and experimental results support the hypothesis that the combustion of aluminum–ice mixtures is controlled by diffusion processes across the oxide layers of particles.     

The impact of the modified Poisson–Boltzmann model on protein bound to a lipid coated silicon nanowire field effect transistor biosensor in an electrolyte environment

The aim of this work was to analyse the electrostatic potential profile, various effects of electrolyte concentrations, and the influences of surface charge on a protein bound to a lipid coated Silicon nanowire field effect transistor (Si-NW FET) biosensor by implementing the modified Poisson–Boltzmann (MPB) model. In this work, we modelled a lipid monolayer-coated Si-NW FET for the sensing of proteins, which consisted of variable amounts of aspartic acid. The electrostatic potential profile, protein charge distributions, the response to various electrolyte concentration, and the impacts of various surface charge were studied by implementing the MPB model with the Si-NW FET biosensor. Additionally, a comparison between the use of the MPB and the Poisson–Boltzmann model in studying the effects of various surface charges was carried out. Taken together, it was found that the MPB model showed a higher resolution in studying the Si-NW FET biosensor model when higher concentrations and surface charges were administered.     

Synthesis and Characterization of Some BODIPY‐based Substituted Salicylaldimine Schiff Bases

Salicylaldimine Schiff bases represent an important class of hetero‐polydentate ligands capable of forming mononuclear, binuclear, and polynuclear complexes with transition and non‐transition metals. In this report, we developed an easy synthesis of BODIPY‐based salicylaldimine Schiff bases and synthesized five new derivatives. These were characterized by elemental analysis, infrared, UV‐Vis, nuclear magnetic resonance spectroscopy, and X‐ray crystallography. Finally, one of the Schiff bases was reacted with BF₃·OEt₂ to synthesize corresponding bis‐BF₂ boron complex. The photophysical and electrochemical properties of the Schiff bases and the boron complex were evaluated and rationalized by theoretical calculations. The bis‐BF₂ boron complex showed excited state charge redistribution, thus could be useful as sensitizers for designing new dye‐sensitized solar cells.