The effect of large strains on ageing of a filled elastomer

Strain endurance experiments on a filled elastomer were performed at several temperatures. It was found that superimposed prestraining accelerated the ageing process. This process was caused by microstructural changes in the elastomer. In order to evaluate the mechanical properties of a filled elastomer it is necessary to take into consideration not only the ageing effects but also the loading history.     

Deposition mechanisms in langmuir-blodgett films

As part of a study of the possible application of polymerisable Langmuir-Blodgett (LB) films as ultra-fine-line e-beam resists, an investigation of the variation of film structure of 22-tricosenoic acid with differing deposition conditions has been made. Unexpected effects with significant implications for deposition speed and resist sensitivity have been observed, and the new techniques for film characterisation developed during the investigation have resulted in a revised model of deposition explaining the observed independence of the disorder causing optical scattering and the macroscopic features observed by polarised microscopy.     

Refractive index profiling-state of the art

Problems associated with different calibration techniques and some instrumental effects that can determine instrumental accuracy are discussed. It is shown how transmission effects can be observed and used to generate a correction curve for refracted near-field instruments. High-quality fiber slices needed for axial interferometry were used to obtain refractive index differences on suitable fibers to ±1% with the measurements traceable to national standards. Interferometry was used to calibrate a multiple-step fiber which is available in 10-m lengths with a certificate of calibration. The limitations of the technique are discussed, and preliminary results of a study on the effects of residual stress and stress relief on measurements are given. Comparisons are made between measurements made by axial interferometry and refracted near field on a range of fibers. It is shown that commercial profilers can produce reliable measurements of refractive index difference, absolute refractive index, profile shape, and numerical aperture that agree well with measurements by other techniques     

Lyapunov‐stable discrete‐time model reference adaptive control

Discrete‐time model reference adaptive control (MRAC) is considered with both least squares and projection algorithm parameter identification. For both cases complete Lyapunov proofs are given for stability and convergence. The results extend the approach of Johansson (Int. J. Control 1989; 50 (3):859–869) to include Lyapunov stability for MRAC when the normalized projection algorithm is used for parameter identification. Copyright © 2005 John Wiley & Sons, Ltd.     

A comparison of commonly used hydrologic design methods for rainwater collectors

Rainwater collection as a possible water source in developing countries is introduced. The major parameters in calculating the size of the tank are defined. Six methods that have been used previously to relate demand, storage, reliability and the rainfall pattern are compared to the Ottawa Model over a wide range of demands.     

Latest Developments in the Batchwise Application of Hot-dyeing Reactive Dyes to Cellulosic Knitwear

A dyeing profile for a range of reactive dyes suitable for application to cellulosic knitwear is defined. Such a profile shows good level-dyeing, reproducibility and fastness properties together with potential for simplified dyeing processes.     

CoGaInS4: A new layered compound

We report on the synthesis results obtained for some compositions in the Co(GaxIn_1-x)₂S₄ family, whose intermediate member CoGaInS₄ is shown to display a layered structure. This result is discussed and compared with the literature.     

On ochratoxin A and fungal flora in Polish cereals from conventional and ecological farms. Part 2: occurrence of ochratoxin A and fungi in cereals in 1998.

Over 200 samples of Polish cereal grain from the 1998 harvest obtained from conventional and ecological farms were investigated for the presence of ochratoxin A and for contamination by microscopic fungi. The frequency of contamination of rye and barley grains from conventional and ecological farms was similar in most cases; it varied from nearly 5 to 12%, respectively, for both types of farming. However, in samples from ecological farms, higher maximum concentrations of ochratoxin A were observed (35 micro g kg(-1), overall range 1.4-35.3 micro g kg(-1)) for both cereals rye and barley in comparison with rye and barley from conventional farms (maximum levels of 8.8 and 9.7 micro g kg(-1), respectively). However, wheat grain from the conventional farms showed ochratoxin A concentrations in a very wide range from 0.6 to 1024 micro g kg(-1) and the average frequency of contaminated samples was about 48%. In contrast, in wheat samples from ecological farming, the presence of ochratoxin A ranged from 0.8 to 1.6 micro g kg(-1) (mean 1.2 micro g kg(-1)) and the frequency of contamination was 23%. From samples containing detectable amounts of ochratoxin A, fungi producing ochratoxin A under laboratory conditions were isolated. They were classified as belonging to the species Penicillium cyclopium, P. viridicatum, Aspergillus ochraceus group, A. glaucus and A. versicolor. Penicillium strains-species known to be producers of ochratoxin A-were isolated from 71% of the samples; in 28% of samples, only Aspergillus strains (species known to be producers of this mycotoxin) were noted. These results have been compared with those obtained in 1997.