Field Theoretic Cogalois Theory via Abstract Cogalois Theory

Abstract Cogalois Theory for arbitrary profinite groups was initiated by T. Albu and ?.A. Basarab [An Abstract Cogalois Theory for profinite groups, J. Pure. Appl. Algebra 200 (2005) 227-250]. The aim of this paper is twofold: firstly, to present the abstract group theoretic versions of various types of Kummer field extensions, and secondly, to show how some basic results of the (Field Theoretic) Cogalois Theory can be very easily deduced from their abstract versions.     

Numerical calculation and experimental measurement of temperatures and welding residual stresses in a thick-walled T-joint structure

Journal of Thermal Analysis and Calorimetry - In this investigation, a T-joint numerical welding simulation of thick steel plates is performed to estimate transient temperature distributions,...     

Asymmetric Mannich reaction catalyzed by N-arylsulfonyl-l-proline amides

Proline-derived N-sulfonylcarboxamides efficiently catalyze the asymmetric Mannich reaction of cyclic ketones with N-(p-methoxyphenyl)-protected iminoglyoxylate. Both classical organic solvents and ionic liquids were used as the reaction media. With cyclohexanone, the reaction proceeded with high enantioselectivity (99% ee). Enamine intermediates were investigated by DFT calculations.     

NMR-Based Liquid Explosives Detector

Liquid explosives pose a threat to security on airplanes and other public places, since they can easily be concealed as benign liquids. A detector, able to quickly identify liquids, would increase the possibility to detect such threats and speed up security checks. As a step towards a long-term goal to develop a liquid explosive detector, we have constructed an experimental setup based on a low-cost 1.1 T permanent magnet with huge static magnetic field gradient of 4.8 T/m, which allows us to measure proton relaxation times T ₁ and T ₂ and the self-diffusion coefficient D in liquid samples in a thin slice excited by radio-frequency pulses. We have developed a simple model in order to explain diffusion-enhanced non-exponential magnetization recovery in inversion recovery T ₁ experiment in this setup. Measuring a wide variety of liquid samples, we have demonstrated that it is possible to discriminate between the liquids based solely on these parameters. We discuss further improvements to the detection method, among those the choice of magnetic field, based on the fast field-cycling measurements.     

Unusual Temperature-Retention Dependences Observed for Several Benzodiazepines in RP-HPLC Using Different Mobile Phase Compositions

Non-linear van’t Hoff plots were observed for several benzodiazepines over the usual temperature interval used in RP-LC (10–60 °C), when acetonitrile was added in the mobile phase. Such deviation from linearity was not observed when methanol or isopropanol was added to the mobile phase. Polynomial regressions were applied to fit the experimental data when acetonitrile was used as organic additive in mobile phase. The second-order polynoms may allow finding out the maximum retention depending on temperature, which can be within or out of the normal temperature range used in RP mechanism. A thermodynamic model deriving from the partition of two or more tautomers of the same analyte was proposed to explain this deviation from linearity of van’t Hoff plots.     

FTIR Spectroelectrochemical Investigation of the trans-[Ru(NO)(dimethylglyoximate)2Cl] Complex: Vibrational Characterization of the NO+/0 and RuIII/II Redox Couples

Abstract

This paper deals with the spectroelectrochemical characterization of the Ru^III/II and N0^+/0 oxidation states of the trans-[Ru(NO)(dmgH)₂Cl] complex (dmgH = dimethylglyoximate ion). The cyclic voltammograms of the complex in acetonitrile solution exhibited a reversible wave at -0.09 V versus SHE, and two less intense waves at 1.19 and 1.41 V. Visible-UV spectra were recorded at -0.4 and 1.5 V, however, the absorption bands collapsed into a single tail, providing little information on the redox states involved. In contrast, in the FTIR measurements at -0.4 V, the v(NO) peak shifted from 1878 to 1855cm^?1, without changing the vibrational peaks of the dmgH ligand, indicating an electrochemical process involving the NO^+/0 redox couple. At 1.5 V, the changes in the vibrational peaks of the NO and dig lagans indicated a redox process associated with the Ru^III/II redox'couple. The existence of an open and a cyclic hydrogen bridged configuration was proposed, in order to explain the occurrence of two electrochemical waves at positive potentials.     

Estimation of W0/WT ratio for cloud-to-ground lightnings

The aim of this paper was to obtain the quantitative estimation of the W₀/W_T (initial electric energy/atmospheric parameter of a surrounding medium) ratio for CG lightnings initiated with a stepped leader process. The results of analytical and numerical models show that the W₀/W_T ratio for CG lightnings spans the range of approximately two orders of magnitude 20 ≤ W₀/W_T ≤ 2000. The results also suggest that CG lightnings differ significantly from small-scale discharges in the laboratories: the thundercloud CG lightnings occur at considerably lower initial electric energy, higher atmospheric parameter of the surrounding medium or a combination of both.     

Confocal Raman and electronic microscopy studies on the topotactic conversion of calcium carbonate from Pomacea lineate shells into hydroxyapatite bioceramic materials in phosphate media

Conversion of Pomacea lineate shells into hydroxyapatite (HA) bioceramic materials was investigated by their in vitro treatment with phosphate solutions, at room temperature. Confocal Raman microscopy revealed that the conversion proceeds at distinct rates through the nacreous or periostracum sides of the shell. The conversion can be accelerated using powdered samples, yielding biocompatible materials of great interest in biomedicine.     

Distance-residual subgraphs

For a connected finite graph G and a subset V₀ of its vertex set, a distance-residual subgraph is a subgraph induced on the set of vertices at the maximal distance from V₀. Some properties and examples of distance-residual subgraphs of vertex-transitive, edge-transitive, bipartite and semisymmetric graphs are presented. The relations between the distance-residual subgraphs of product graphs and their factors are explored.