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.     

Addendum to: generic rules to evaluate system-failure frequency

In the paper on Generic rules to evaluate system-failure frequency, (see ibid., vol.49, p.85-7, 2000) the authora did not consider the case of shorter mission times while presenting the rules to evaluate system-failure frequency. Time-specific failure-frequency calculations are required for the systems with shorter mission times. One of the practical uses of time-specific failure-frequency is in finding reasonably accurate estimates of failure-rate and reliability of large systems consisting of repairable components, by using combinatorial methods (without using Markov models). This paper shows that, with some minor modifications, the rules in the original paper for evaluating steady-state failure-frequency can be used to find the time-specific failure-frequency     

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.     

Relationship between platelet cyclooxygenase pathway and plasma malondialdehyde-like material

Thrombin-induced platelet malondialdehyde (MDA) formation and plasma malondialdehyde-like material (MDA-LM) were evaluated in 12 healthy subjects before and after 1 and 7 days from aspirin (1 g) ingestion. 24 hr after aspirin administration, platelet MDA was almost abolished while MDA-LM showed a 23% decrease. Platelet MDA and plasma MDA-LM returned to baseline values 7 days after aspirin ingestion. These data suggest that platelet cyclooxygenase pathway affects only in part plasma MDA-LM. The evaluation of plasma MDA-LM before and after aspirin could be useful for evaluating in vivo platelet cyclooxygenase activation.     

Acoustic emission technique for leak detection in an end shield of a pressurised heavy water reactor

This paper discusses the successful application of the Acoustic Emission Technique (AET) for detection and location of leak paths present on the inaccessible side of an end shield of a Pressurised Heavy Water Reactor (PHWR). The methodology was based on the fact that air and water leak AE signals have different characteristic features. Baseline data was generated from a sound end-shield of a PHWR for characterizing the background noise. A mock up end-shield system with saw cut leak paths was used to verify the validity of the methodology. It was found that air leak signals under pressurisation (as low as 3 psi) could be detected by frequency domain analysis. Signals due to air leaks from various locations of a defective end-shield were acquired and analysed. It was possible to detect and locate leak paths. Presence of detected leak paths were further confirmed by alternate test.