Arc root mobility on piezoelectrically actuated contacts in miniature circuit breakers

A novel contact opening mechanism has been developed using a piezoelectric actuator to open the contacts in a low contact opening velocity circuit breaker. The arc control on the contacts is critical for successful current interruption (10/sup 3/-10/sup 4/ A) in low voltage (<250V) devices. Previous work has shown how arc root commutation from the contact region into the arc chamber is affected by arc chamber materials, contact materials and the gap behind the moving contact for contact velocities between 1ms/sup -1/ and 10ms/sup -1/. This work is extended using a commercially available piezoelectric actuator to open the contacts. Contact opening speeds are assessed and the arc root mobility is characterized under this operating regime. A flexible test apparatus and solid-state high-speed arc imaging system are used to gather data on the arc root during the opening of the contacts. New experimental results are presented on the anode and cathode root velocity and arc root motion in an arc chamber with piezoelectrically actuated contact opening. These results can be used to improve the design of high current low voltage circuit breakers suitable for piezoelectric actuation.     

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet.

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.     

Financial Analysis and Marketing Strategy

A combination of concept (the product portfolio and the product life cycle) and empirical research (the PIMS study) can aid in clarifying the key issues involved in the selection of a firm's core strategies. Strategy control is multistage: periodic re-evaluation of strategy alternatives by use of the marketing audit; an analytical framework for control of chosen strategies by breaking down components and reporting their performance variances; and 'marketing segment' analysis for control of the detailed marketing plan.?     

Sensory analysis of polystyrene packaging material taint in cocoa powder for drinks and chocolate flakes

Polystyrene packaging material taint was sensorily evaluated in cocoa powder for drinks and chocolate flakes using short-cut signal detection measures on differences between control and test samples and on recognition of styrene. No differences were observed in cocoa powder for drinks and plain chocolate flakes treated with 0.5 dm2 polystyrene of 1 mm thickness. However, differences were detected in milk chocolate flakes and plain chocolate flakes, which were in contact with a larger area or thicker polystyrene packaging material. The latter results were confirmed by the styrene recognition test, so polystyrene is a potential source of off-flavour for chocolate products. The amount of residual styrene in the polystyrene used was about 320 ppm, while the amounts of styrene ranged from 7 to 132 ppb in cocoa drinks and from 414 to 1447 ppb in chocolate flakes.     

Filled Fibrous Sorbents Modified with Transition Metal Ferro- and Ferricyanides for Recovery of Americium and Rare-Earth Metals

Filled fibrous sorbents modified with transition metal ferro- and ferricyanides capable to recover americium(III) and rare-earth metals(III) from nitric acid solutions were prepared. The most complete and rapid recovery is attained on complex-forming and cation-exchange sorbents (as filled fibrous materials) saturated with nickel ions. The sorbents are characterized by good kinetic properties and can be used for recovery of the above metals.     

Online and Offline Rotary Regression Analysis of Torque Estimator for Switched Reluctance Motor Drives

A new torque estimator for switched reluctance motor (SRM) drives based on 2-D rotary regression analysis is presented in this paper. The proposed torque estimator is composed of a bicubic regressive polynomial as a function of rotor position and input current. The regressive coefficients can be computed offline or online from the torque characteristics acquired either experimentally or from numerical computation. Furthermore, a torque estimation method by taking mutual coupling into consideration is proposed. It can be seen that the estimated and experimentally obtained self-coupling and mutual-coupling torque characteristics are in good agreement with each other. In addition, the dynamic torque waveforms with and without the mutual coupling, estimated by the proposed estimator, are found to be virtually the same as those obtained from the bicubic spline interpolation for SRM drives with single-pulse voltage, hysteresis current chopping, as well as with voltage pulse width modulation control. The success of all the case studies being reported is a good validation of the usefulness and accuracy of the proposed real-time torque estimator that, as described in this paper, can be used to quickly estimate the instantaneous output torque of SRM drives.     

Optical properties of doped bismuth telluride crystals in the region of plasma effects

The optical properties of bismuth telluride crystals doped with donor-and acceptor-type impurities are studied. The fact that energy corresponding to the resonance frequency of plasma oscillations of free charge carriers (plasmons) approaches the band-gap energy is detected in the infrared spectral region, where the main elementary excitations in the electronic system of these materials are observed. The mentioned approach of energies varies the intensity of electron-plasmon interaction, which affects the recombination processes in the materials widely used for the fabrication of thermoelectric energy converters.     

3D velocity from 3D Doppler radial velocity

We present local least squares and regularization frameworks for computing 3D velocity (3D optical flow) from 3D radial velocity measured by a Doppler radar. We demonstrate the performance of our algorithms quantitatively on synthetic radial velocity data and qualitatively on real radial velocity data, obtained from the Doppler radar at Kurnell Radar station, Botany Bay, New South Wales, Australia. Radial velocity can be used to predict the future positions of storms in sequences of Doppler radar datasets.© 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 189–198, 2005