Mathematical modelling in the analysis and design of hard and soft measurement systems

This paper briefly looks into the role and extent of mathematical modelling in the design and analysis of measurement systems, especially measurement sub-systems in the form of instruments and instrument elements. These fall within the classical domain of hard measurement (physical, strongly-defined measurement). It also examines the role and use of mathematical modelling in the area of soft measurement (non-physical, weakly defined measurement). These constitute two sub-sets of widely-defined measurement. Based on a number of examples it demonstrates the use of modern modelling techniques in the design and analysis of sub-systems in measurement technology. In doing so, it focuses on the scope and importance of physical modelling at a sub-system level, which ultimately contributes to modelling activities at a global systems level.     

Co-continuous nanostructured nanocomposites by reactive blending of carbon nanotube masterbatches

Masterbatches of reactive polymers containing carbon nanotubes are used to prepare nanocomposites by reactive blending. By mixing masterbatches of low molecular-weight amino-terminated polyamide-6 (PA6) containing ～10 wt% or ～17 wt% of multi-walled carbon nanotubes (MWNT) with maleic anhydride functionalized polyethylene (PE*) at temperatures above melting of PA6 it is possible to obtain fine and homogeneous dispersions of carbon nanotubes. In the PA6 concentration range explored, from 19 wt% to 37 wt%, nanostructured co-continuous blend morphologies are achieved. Selective extractions show that a high amount of graft copolymer PE*-g-PA6 is synthesized during mixing. The swelling experiments in selective solvents demonstrate co-continuous blend morphologies. Electron microscopy confirms good quality of MWNT dispersion and shows structures on mesoscopic scales. Fine dispersion of carbon nanotubes and the matrix co-continuity concur to yield a unique combination of properties such as solvent resistance, electrical conductivity, mechanical strengthening and ductility.     

Catalytic Method for N-Methyl-4-pyridone Synthesis in the Presence of ZnAl2O4

A composite oxide ZnAl₂O₄ was prepared by microwave-assisted hydrothermal treatment, a precursor mixture of hydroxides obtained by precipitation of aluminium and zinc nitrates. Characterization by TEM, XRD and textural studies shows that ZnAl₂O₄ is nanosized and is a micro/mesoporous material with large a surface area (140 m²/g). The gas phase catalytic methylation of 4-hydroxypyridine in the presence of the ZnAl₂O₄ catalyst was performed in a continuous process at atmospheric pressure in the temperature range of 240–360 °C. A mixture of O- and N-alkylated products, namely 4-methoxypyridine and N-methyl-4-pyridone were obtained. The alkylation of 4-hydroxypyridine with methanol at 345 °C offered 87.6% selectivity towards N-methyl-4-pyridone with about 89% 4-hydroxypyridine conversion.     

Ketonization of long chain esters from transesterification of technical waste fats

The methyl ester mixture obtained from rape oil, and the mixture of butyl esters produced from animal fatty acids, were converted into mixtures of ketones with a total yield above 65%. The experiments were performed at atmospheric pressure in a temperature range of 300–400 °C using a standard flow system, with an iron catalyst modified with silicon, chromium, and potassium oxides, in the molar ratio of 100 : 2 : 1 : 0.1. The described method may extend the prospects of using waste technical fats. © 2001 Society of Chemical Industry     

Synthesis of (2′-Methyloxiranyl)quinones as bioreductive alkylating agents

1,4-Benzoquinones and 1,4-naphthoquinones bearing 2′-methyloxiranyl substituents have been synthesized as new bioreductive alkylating agents. The method presented here involved the synthesis of 2-acetyl-1,4-dimethoxybenzenes 6a, b, d and -naphthalenes 6c, e, f , conversion of the acetyl group into 2′-methyloxirane ring using trimethylsulfonium chloride and sodium hydroxide in anhydrous medium, and oxidative demethylation of these intermediates 7a-f to quinones 8a, c, e, f with silver(II) dipicolinate.     

Remarkable solvent effect on the structure and electrochemical properties of [M(bipyridyl)3](ClO4)3 (M = Co, Fe and Ru) films

In low dielectric constant media the electrooxidation of bipyridyl complexes of transition divalent metal cations, such us Fe(II), Co(II), and Ru(II) results in the precipitation of microcrystalline film on the electrode surface. In most solvents, the film is reversibly reduced. However, films formed in the presence of acetonitrile are electrochemically inactive over a large potential range. The morphology and crystallographic structure of solid phase formed on the electrode surface during the electrochemical oxidation of bipyridyl complexes of Co(II), Fe(II), and Ru(II) have been investigated by the scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transformation-IR/horizontal attenuated total reflectance (FT-IR/HATR) spectroscopy and elemental analysis. A correlation between the electrochemical properties and the structure of the film has been found. The electrochemically inactive films of Co(II) and Fe(II) complexes formed in the presence of acetonitrile in solution consist of densely packed column-like crystallites. They exhibit monoclinic symmetry P/2m (no. 10). The other films formed in acetonitrile free solutions, form flower-like aggregates of orthorhombic symmetry Pmmm crystals (no. 47). These films are very porous.