Experiences in Expert Systems

This paper describes some work carried out in the Scientific Research and Development Branch (SRDB) of the Home Office, intended to contribute to an overall aim of building up internal expertise in the field of expert systems. This was done by carrying out a number of pilot and demonstrator projects, two of which are described in some detail. The plan, which proved successful, was to build as far as possible on the relevant skills already possessed by an OR group in the branch. The lessons learned from these are summarized in the hope that they will be of use to other groups who wish to become involved in this important area.     

Numerical simulations of a filament in a flowing soap film

Experiments concerning the properties of soap films have recently been carried out and these systems have been proposed as experimental versions of theoretical two‐dimensional liquids. A silk filament introduced into a flowing soap film, was seen to demonstrate various stable modes, and these were, namely, a mode in which the filament oscillates and one in which the filament is stationary and aligns with the flow of the liquid. The system could be forced from the oscillatory mode into the non‐ oscillatory mode by varying the length of the filament. In this article we use numerical and computational techniques in order to simulate the strongly coupled behaviour of the filament and the fluid. Preliminary results are presented for the specific case in which the filament is seen to oscillate continuously for the duration of our simulation. We also find that the filament oscillations are strongly suppressed when we reduce the effective length of the filament. We believe that these results are reminiscent of the different oscillatory and non‐oscillatory modes observed in experiment. The numerical solutions show that, in contrast to experiment, vortices are created at the leading edge of the filament and are preferentially grown in the curvature of the filament and are eventually released from the trailing edge of the filament. In a similar manner to oscillating hydrofoils, it seems that the oscillating filaments are in a minimal energy state, extracting sufficient energy from the fluid to oscillate. In comparing numerical and experimental results it is possible that the soap film does have an effect on the fluid flow especially in the boundary layer where surface tension forces are large. Copyright © 2004 John Wiley & Sons, Ltd.     

Corn stover fractions and bioenergy

Information is presented on structure, composition, and response to enzymes of corn stover related to barriers for bioconversion to ethanol. Aromatic compounds occurred in most tissue cell walls. Ferulic acid esterase treatment before cellulase treatment significantly improved dry weight loss and release of phenolic acids and sugars in most fractions over cellulase alone. Leaf fractions were considerably higher in dry weight loss and released sugars with esterase treatment, but stem pith cells gave up the most phenolic acids. Results help identify plant fractions more appropriate for coproducts and bioconversion and those more suitable as residues for soil erosion control.     

Global Solution of Optimization Problems with Parameter-Embedded Linear Dynamic Systems

This paper develops a theory for the global solution of nonconvex optimization problems with parameter-embedded linear dynamic systems. A quite general problem formulation is introduced and a solution is shown to exists. A convexity theory for integrals is then developed to construct convex relaxations for utilization in a branch-and-bound framework to calculate a global minimum. Interval analysis is employed to generate bounds on the state variables implied by the bounds on the embedded parameters. These bounds, along with basic integration theory, are used to prove convergence of the branch-and-bound algorithm to the global minimum of the optimization problem. The implementation of the algorithm is then considered and several numerical case studies are examined thoroughly     

Application of high-performance liquid chromatography to the measurement of cortisol secretion rate

After administration of [3H] cortisol, the specific radioactivity of the urinary cortisol metabolites is determined by chemical conversion of the 17-hydroxycorticosteroid conjugates to 17-ketosteroids, extraction with Sep-Pak C18 cartridges, derivatisation with 2,4-dinitrophenylhydrazine and isocratic reversed-phase high-performance liquid chromatography. This allows on-line measurement of ultra-violet absorbance; fractions are collected and 3H is measured by scintillation counting. Alternatively extraction and chromatography are done after enzymic hydrolysis of the steroid conjugates, and the major metabolites are determined colorimetrically in the fractions. The results from the two methods were consistent with each other and with published data.     

DNA electrochemistry through the base pairs not the sugar-phosphate backbone

Using intercalated, covalently bound daunomycin as a redox probe, ground state charge transport in DNA films with a perturbation in base pair stacking was examined in comparison with breaks in the sugar-phosphate backbone. While the introduction of one or even two nicks in the sugar-phosphate backbone yields no detectable effect on electron transfer, a CA mismatch significantly attenuates the electron transfer yield. These results confirm that the base pair stack is the pathway for DNA-mediated charge transfer, not the sugar-phosphate backbone.     

The preparation,phase relationships,and Eu-151 Mössbauer spectroscopy of europium tungsten bronzes and related phases

Crystal chemistry and phase relations for the bronze-forming region of the EuWO system have been investigated. A bronze Eu_xWO₃ is stable up to 1000°C when x ? 0.125 and in the region 0.085 ? x ? 0.125 the symmetry is cubic. A tetragonal bronze exists at x = 0.05, and an orthorhombic bronze with a structure closely related to the orthorhombic form of WO₃ exists below x = 0.01. Mössbauer spectra at room temperature and at 80 K indicate that in all these phases the europium is highly ionized as Eu(III) with no electron localization to give (EuII) even at low values for x. The decomposition products of the bronzes have been established, and the Mössbauer parameters for the highly nonstoichiometric tungstates Eu_xWO₄ were determined. Both Eu(II) and Eu(III) resonances were obtained, and a cation vacancy model for Eu_xWO₄ was found to fit the data best. In conformity with the foregoing data, a sample of composition “Eu₂W₂O₇” was found not be be a pyrochlore but to comprise a mixture of Eu₆WO₁₂, Eu_xWO₄, and W. The phase relationships for the europium bronze system Eu_xWO₃ are compared with those of other ionic bronzes Na_xWO₃, Li_xWO₃, and Al_xWO₃.     

Radical addition to vinyl sulphones and vinyl phosphonium salts

Alkyl radicals, derived from decarboxylation of carboxylic acids, add readily to phenyl vinyl sulphone and vinyl phosphonium bromide. The adducts may be further converted into a variety of useful synthetic intermediates.