Table of contents

A multichannel taste sensor, namely an electronic tongue, with global selectivity is composed of several kinds of lipid/polymer membranes for transforming information about substances producing taste into electrical signals, which are input to a computer. The sensor output exhibits different patterns for chemical substances which have different taste qualities such as saltiness, sourness and bitterness, whereas it exhibits similar patterns for chemical substances with similar tastes. The sensor responds to the taste itself, as can be understood from the fact that taste interactions such as the suppression effect, which appears for mixtures of sweet and bitter substances, can be reproduced well. The suppression of the bitterness of quinine and a drug substance by sucrose can be quantified. Amino acids can be classified into several groups according to their own tastes on the basis of sensor outputs. The tastes of foodstuffs such as beer, coffee, mineral water, milk, sake, rice, soybean paste and vegetables can be discussed quantitatively using the taste sensor, which provides the objective scale for the human sensory expression. The flavour of a wine is also discriminated using the taste-odour sensory fusion conducted by combining the taste sensor and an odour-sensor array using conducting polymer elements. The taste sensor can also be applied to measurements of water pollution. Miniaturization of the taste sensor using FET produces the same characteristics as those of the above taste sensor by measuring the gate-source voltage. Use of the taste sensor will lead to a new era of food and environmental sciences.

We describe an electronic tongue which consists of a reference electrode, an auxiliary electrode and five wires of different metals (gold, iridium, palladium, platinum and rhodium) as working electrodes. The measurement principle is based on pulsed voltammetry, in which successive voltage pulses of gradually changing amplitudes are applied to the working electrodes connected in a standard three-electrode configuration. The five working electrodes were successively connected and corresponding current-response transients are recorded. The electronic tongue was used to follow the deterioration of the quality of milk due to microbial growth when milk is stored at room temperature. The data obtained were treated with principal component analysis and the deterioration process could clearly be followed in the diagrams. To make models for predictions, projections to latent structure and artificial neural networks were used. When they had been trained, both models could satisfactorily predict the course of bacterial growth in the milk samples.

Phosphor thermography is a laser-induced fluorescence method utilized for the temperature sensing of rotating components within inhospitable environments. Results presented here show that thin film coatings for thermographic sensors have a much higher durability than conventional thick film coatings. Room-temperature measurements demonstrate that the intensity of the luminescent emission from thin films is equivalent to that from thick films. Lifetime measurements carried out at C show that thin films survived for up to ten hours, whereas thick film samples survived for less than one. More importantly, post-run measurements of thin films indicate little degradation in the intensity of the fluorescent signal. This illustrates the capability of thin film sensors for remote temperature sensing.

We describe a software program designed to control a broadband pulse nuclear magnetic resonance (NMR) spectrometer used in zero-field NMR studies of magnetic metals. The software is written in the graphical language Labview. This type of programming allows modifications and the inclusion of new routines to be carried out easily by the non-specialist, without changing the basic structure of the program. The program corrects for differences in the gain of the two acquisition channels (U (phase) and V (quadrature)), and automatic baseline subtraction. We present examples of measurements of NMR spectra, spin-echo decay , and quadrupolar oscillations, performed in magnetic intermetallic compounds.

A periodic radiometric technique for determining the total emissivity of insulating materials at moderate temperatures is presented. The radiometric technique involves a multifrequency modulation of the front-side temperature of the sample. This method needs two measurements: one on the studied sample, the other one on a modulated thin reference. The infrared output signal of the other side (the back side) as well as the front-side temperature of the sample are measured. The measured signals are fitted with a temperature-modulated conduction model, providing the emissivity without surface-temperature measurement. As an experimental validation 25 measurements are carried out on a PVC sample 5 mm thick coated with aluminium paint. The results are consistent with the results obtained by two other methods, the monofrequency radiometric method and the integrating directional measurements.

Photoresist diffraction gratings of 1200 lines mm^-1 were produced directly on Ti-6Al-4V beam specimens to study fatigue crack closure using moiré interferometry. A dyed photoresist was used to overcome the problems of reflection causing standing waves in the photoresist. Dipping was the best method of applying an even layer of photoresist to the specimen. The specimens were manufactured oversize, then machined to size after the gratings had been produced, to remove the bead at the specimen edge. This paper outlines the processes required to produce the photoresist gratings and a brief description of the combined moiré interferometer and fatigue rig used.

We report here a simple, low-cost all-fibre grating strain sensing interrogation technique offering high static-strain resolution and large dynamic range . A key interrogating component of this technique is a long-period grating which acts as an edge filter converting strain-induced wavelength variation into optical power measurement. The transmission profile of the long-period grating is shown to be nearly linear over a sufficiently wide range, yielding a linear relationship between the resultant intensity and applied strain, and a high resolution achieved by standard lock-in techniques.

An infrared thermography imaging system is described for spatially resolved convective heat transfer measurements when used in conjunction with thermocouples, energy balances, digital image processing, zinc-selenide windows, and unique in situ calibration procedures. The usefulness of the system and the techniques developed are demonstrated by measurements made in two different environments with complex, three-dimensional flow features. First, spatial variations of surface Nusselt numbers are measured along the concave surfaces of a swirl chamber whose geometry models an internal passage used to cool the leading edge of a turbine blade. Second, spatially resolved distributions of the adiabatic film-cooling effectiveness are measured downstream of film-cooling holes on a symmetric turbine blade in transonic flow.

Overhauser imaging in a magnetic field of 16 mT was employed for a study of water transport during the drying process of an agar gel. The data illustrate important aspects of Overhauser imaging, such as the large sensitivity to small changes of local moisture, which may be attainable under appropriate conditions. The non-Fickian nature of the water transport process can be clearly inferred from the measured moisture profiles.

This paper describes the design and performance of a self-matched, transmission line pulse generator, which is capable of producing a single, high-voltage, output pulse with no subsequent reflections, regardless of the value of the load impedance. The operation of the pulse generator is loosely based on that of the self-matched, single-pulse generator described by Ishii and Yamada (1985 Rev. Sci. Instrum. 56 2116-18), but involves an improved charging and inter-component connection scheme which increases the overall efficiency of the generator and maintains a good pulse profile. The generator incorporates a number of individual transmission line modules, each constructed from lengths of URM67 coaxial cable with a transit time of 25 ns. Five modules were connected in parallel to achieve an output impedance of . The device is suitable for applications which require a single high-voltage and high-current pulse with a fast risetime.

Variations in several electron paramagnetic resonance (EPR) spectral parameters of importance in retrospective dosimetry of tooth enamel were measured using instrumentation and methodologies designed to maximize measurement reproducibility. Measurements were made using accessory EPR equipment that can be readily constructed with little more than a variable power supply, a geared down motor and some high-purity CaO. Spectroscopic precision is considerably enhanced due to elimination of sample anisotropies by scanning samples throughout their angular range. Frequency drifting incurred by sample reorientation and instrument/sample warm-up is effectively eliminated using an in-cavity :CaO standard. This work shows that for highly anisotropic samples, spectral characteristic parameters (peak-to-peak amplitudes, signal component widths and positions) are reproduced with equal or comparable precision to the case where standard EPR configurations are used while measuring approximately isotropic samples.

The problem of assessing the incidence of the x errors on the fitting parameters and their uncertainties in straight-line fittings is addressed. The case in which the x and y errors are proportional to each other is studied in detail. Limits for the maximum expected variation of the fitting values due to the inclusion of the x errors are given in terms of the standard fitting results, namely those obtained disregarding the x errors. Closed expressions for the parameters' values and their uncertainties are also given in terms of the standard fitting results. The main inaccuracies of the standard fitting are investigated analytically. The general case of point-dependent errors is also briefly discussed.

A new laser range finder electronic system for counting and displaying has been developed and tested. Its originality stems from its capability of simultaneously measuring the distances of two targets using one single photodetection, amplification, counting and displaying chain. This present circuit achieves a 10 m distance resolution between successive targets. Targets situated at ranges of 15 km along the line of sight of the transmitter have been easily detected with false-alarm and missed-signal probabilities of /unit range interval and respectively. The circuit is characterized by its simplicity, compactness, reliability and very low cost of construction.

Modifications were made to a commercial porosimeter in order to measure very low open porosity in materials such as granites (porosity about 1%). A new measuring cell, i.e. the penetrometer, was designed with the highest possible sample holder capacity and with the capillary stem being of a smaller internal diameter than is standard. A specific computer software was also developed to take into account penetrometer distortions and granite and mercury compressions in order to correct the measured porosity values.

This new apparatus was used successfully in measuring the porosity of granite from El Berrocal (Spain) as part of the European Commission Project `Rock Matrix Diffusion' (Contract No FI2W-CT91-0082). In particular, the experimental constraints were examined and the method validated by comparing the obtained results to porosities measured by water saturation.

A method for measuring the Young's modulus of thick-film resistor material is presented. 96% alumina beams were coated with Heraeus 8241 resistor material and flexural tested in the three-point bend mode using a DMA 2980 Thermal Mechanical Analyser. Young's modulus was found to decrease linearly over the 173 K to 573 K temperature range. There was no evidence of non-elastic behaviour. Modulus results for the alumina substrate relate closely to published data. This method could be used to measure the modulus of a wide variety of thick-film coatings on substrates.

1999 February 17-18 Sensor and Transducer Conference at mtec '99, National Exhibition Centre, Birmingham, UK Details: Robert Bogue, mtec Conference Chairman, Tamar House, Tuckermarsh, Bere Alston, Devon PL20 7HB, UK. Telephone: +44 1822 840 434, fax: +44 1822 841 300 March 30 March-1 April Symposium on Design, Test and Microfabrication of MEMS/MOEMS, Paris, France Details: B Courtois, telephone: +33 4 7657 4615, fax: +33 4 7647 3814, e-mail: Bernard.Courtois@imag.fr April 13-15 International Workshop on Optical Measurements '99, Liverpool, UK Details: Telephone: +44 151 231 3585, fax: +44 151 709 5057, e-mail: ems@livjm.ac.uk, WWW: http://www.ceorg.livjm.ac.uk/opticalmeas99/ May 17-21 3rd CCM Conference on Pressure Metrology from Ultra High Vacuum to Very High Pressures (10-7 Pa to 109 Pa), Torino, Italy Details: M Bergoglio, Istituto di Metrologia `G Colonnetti', Strada delle Cacce 73, 10135 Torino, Italy. E-mail: bergoglio@imc.to.cnr.it 18-20 Sensor '99 9th International Fair and Congress for Sensors, Transducers and Systems, Nürnberg, Germany Details: ACS Organizations GmbH, PO Box 23 52, D-31506 Wunstorf, Germany. Telephone: +49 5033 2015, fax: +49 5033 1056, e-mail: acs@sensor99.de, WWW: http://www.sensor99.de 20-22 ODIMAP II 2nd Topical Meeting on Optoelectronic Distance/Displacement Measurements and Applications, Pavia, Italy Details: AEI-Ufficio Centrale, P.le R. Morandi 2, 20121 Milano, Italy. Telephone: +39 02 777 90205/218, fax: +39 02 798817, e-mail: conferencesaei@aei.it, WWW: http://ipvsm8.unipv.it/leos or http://www.aei.it/odimap2.html 31 May-4 June EUSPEN 1st Conference of the European Society for Precision Engineering and Nanotechnology, Bremen, Germany Details: Professor E Brinksmeier, Universität Bremen FB4/FG06, Badgasteiner Straße 1, D-28359 Bremen. Telephone: +49 421 218 7481, fax: +49 421 218 4455, e-mail: euspen@iwt.uni-bremen.de June 7-10 Transducers '99 10th International Conference on Solid State Sensors and Actuators, Sendai, Japan Details: J Etizen, telephone: +81 3 3299 1371, fax: +81 3 3299 1361, e-mail: tr99@twics.com, WWW: http://www.com.cas.uec.ac.jp/trans99.html 13-18 IMEKO XV World Congress, Osaka, Japan Details: c/o The Society of Instrument and Control Engineers, 35-28-303, 1-Chome Hongo, Bunkyo-ku, Tokyo 113. Telephone: +81 3 3814 4121, fax: +81 3 3814 4699, e-mail: mnami@sice.or.jp 21-25 Frontiers and Science and Measurement, National Physical Laboratory, Teddington, UK Details: Jane Tsakalou, telephone: +44 181 943 6400, fax: +44 181 943 6735, e-mail: jane.tsakalou@npl.co.uk, WWW: http://www.npl.co.uk September 12-15 1st International Symposium on Turbulence and Shear Flow Phenomena, Santa Barbara, CA, USA Details: N Kasagi, Department of Mechanical Engineering, University of Tokyo, Tokyo 113 8656, Japan. Telephone: +81 3 3812 2111 ext. 6417, fax: +81 3 5800 6999, e-mail: kasagi@thtlab.t.u-tokyo.ac.jp, WWW: http://tsfp.t.u-tokyo.ac.jp 12-15 EUROSENSORS XIII, The Hague, The Netherlands Details: R F Wolffenbuttel, telephone: +31 15 278 6287, fax: +31 15 278, e-mail: eurosensors@ei.et.tudelft.nl 16-18 September 3rd International Workshop on Particle Image Velocimetry, University of California-Santa Barbara, USA Details: Professor C D Meinhart, Mechanical and Environmental Engineering Department, University of California-Santa Barbara, CA 93106, USA. Telephone: +1 217 333 3752, fax: 217 244 5707, e-mail: piv99@engineering.ucsb.edu, WWW: http://www.engineering.ucsb.edu/~piv99