Knowledge elicitation using more than one expert to cover the same domain

Knowledge elicitation is accepted as being one of the most problematic areas in the creation of a knowledge-based system.A large amount of research has already concentrated on finding more efficient and effective techniques for eliciting knowledge from an individual expert. However, little attention has been given to the involvement of more than one source of expertise in knowledge-based system development.This paper is based on the authors' practical experience gained when developing a knowledge-based system for the conceptual design of bridges. It shows that the use of more than one expert throughout the knowledge elicitation process can improve both the efficiency of the approach and the quality of the knowledge acquired.     

Optical circulator consisting of a YIG spherical lens, PANDA-fibre polarisers and a fibre-optic polarising beam splitter

A novel optical circulator is reported which employs an yttrium-iron-garnet (YIG) sphere, PANDA-fibre polarisers and a fibre-optic polarising beam splitter. The splitting ratios of the fibre-optic polarising beam splitter were 1.0:99.0 for x-polarisation and 97.5:2.5 for y-polarisation, with an excess loss of 0.5 dB at 1.30 ?m wavelength. The backward isolation of the optical circulator was 30 dB with the total insertion loss of 4.5 dB.     

The effect of plastic deformation on Al2CuLi (T 1) precipitation

The enhancement ofT ₁ precipitation in Al-Li-Cu alloys by plastic deformation prior to aging (that is, cold work) and the subsequent increase in alloy strength is investigated. The increased understanding of the role of matrix dislocations in the nucleation and growth ofT ₁ plates, discussed in the previous paper,^[1] permits a detailed study of the phenomenon. In this paper, the effect of different levels of plastic strain on theT ₁ particle distributions as a function of aging time at 190 °C is quantified, and the subsequent influence on tensile properties is thereby described. The effect of plastic deformation is shown to decrease theT ₁ plate length and thickness, increase the number density by almost two orders of magnitude, increase the yield strength by 100 MPa, while simultaneously reaching peak strength in 20 pct of the time required without plastic deformation. Formerly Graduate Student, Department of Materials Science, University of Virginia,     

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.     

Construction and performance of a multiparameter focal plane detector for use on a QMG/2 magnetic spectrometer

The design, construction and performance of a modular, two pressure focal plane detector, 550 mm long, 1000 mm deep and with an active height of 60 mm are described. The detector has been operated with ions ranging from 50 MeV ¹H to 200 MeV ³⁶S. Typical results achieved are 0.5 mm and 0.3° for the spatial and angular resolutions, and 0.7% and 3% for the total energy and energy loss measurements. A height signal is also provided.     

Untersuchungen zum Korrosionsverhalten von AlLi-Legierungen

Corrosion behaviour of aluminium-lithium alloys The AlLiMgCu alloy 8090 was studied in its texturated fine grained version “A” and in its recrystallized coarse grain structured version “C” in different artificially aged conditions in reference to several other AlLi alloys, each in its heat treatment condition of practical interest, and to the convetional alloy 2024 T3. The subject of research was the general corrosion behaviour of semifinished AlLi products, particularly sheet material, under alternate and permanent immersion conditions in neutral 3.5% sodium chloride solution; the stress corrosion behaviour was studied under constant load in the long transverse direction according to ASTM G44 and G49. The underaged conditions, which are the relevant conditions for technical application of the 8090 “A” and “C” sheets, showed an approximately equivalent or even better corrosion behaviour in comparison to the lithium-free alloy 2024 T3 in the corrosion tests with unloaded specimens. The threshold above which the AlLi alloy 8090 in some heat treatment conditions is attacked by stress corrosion cracking within the 30 days lasting constant load test depends on alloy composition, testing direction, grain size, stretch-forming, artificial ageing condition, surface pretreatment and the specimens' dimensions.     

Electrochemical Faceting of polycrystalline platinum in HF solutions

The electrochemical faceting of polycrystalline (pc) platinum yielding a (100)-preferred oriented electrode surface was accomplished in HF solutions by applying to the pc platinum electrode a square wave potential perturbation at 1 kHz in the 0.2 to 1.3 V range (vs rhe). SEM patterns of the resulting surfaces were also obtained. For HF concentrations up to 2 M no appreciable influence of the electrolyte concentration on the electrochemical faceting was noticed. Otherwise, the voltammetric response of the (100)-type preferred oriented platinum surface in the H-adatom potential range when compared to previously reported data resulted remarkably sensitive to the electrolyte composition. The discussion of results was based on the non-equilibrium adsorption conditions for anions under the periodic perturbation.     

W-band divide-by-3 frequency divider using 0.1 /spl mu/m InAlAs/InGaAs metamorphic HEMT technology

A W-band divide-by-3 frequency divider with wide bandwidth and low power dissipation is presented using harmonic injection-locking technique. A cascode FET is employed for a self-oscillating second-harmonic mixer which is injection-locked by third-harmonic input to obtain the division order of three. The fabricated frequency divider using 0.1 /spl mu/m GaAs metamorphic HEMT technology shows superior performance such as large bandwidth of 6.1 GHz around 83.1 GHz (7.3%) under small DC power consumption of 12 mW.     

Highly monomode W1 waveguide square lattice photonic crystal lasers

Lasing of W1 square lattice-based photonic crystal lasers on the substrate approach is analyzed. A second-order distributed feedback highly monomode behavior is observed. A comprehensive two-dimensional and three-dimensional finite-difference time-domain computation analysis shows that this characteristic arises from the lattice geometry. Single-mode lasers can be obtained using this geometry, opening the way to the realization of monomode laser arrays.