A fuzzy approach to using expert knowledge for tuning paper machines

Paper machines are very complex production systems, but their scope is simple: they consume materials and resources, called factors, to produce paper, which in turn can be described by its characteristics. In this paper, a decision support system is developed in cooperation with an industrial partner to help them with operational decision making when tuning a paper machine. The decision support system was developed in two phases. Firstly, the knowledge of experts is collected and stored in the form of a fuzzy ontology. Secondly, this knowledge is made usable so that a user of the decision support system can specify what characteristics of the produced paper to increase or to decrease and be returned with a recommendation on what factors to change. In this paper, we will work out the optimization problems on which the system is based. Additionally to a basic goal programming model, two extensions are explored, accounting for uncertainty and non-linearity, respectively.     

Edge-compression fixture for buckling studies of corrugated board panels

A test fixture, developed for evaluating the preand postbuckling response of simply supported, nearly flat, rectangular corrugated board panels subjected to edge compression is evaluated. The test fixture enables loading of panels into the postbuckling regime until collapse. The shadowmoiré method verified that buckling in the first mode occurred, and that there was symmetry of the adge-boundary conditions. Through an iterative regression model, experimental curves of load versus out-of-plane displacement for isotropic panels were fitted to an equation governing the nonlinear postbuckling response. This method provides the critical buckling load, a postbuckling parameter and the amplitude of initial imperfection of the panel. Comparison with analytical results revealed that simply supported boundary conditions were closely achieved. Examination of compressively loaded corrugated board panels showed that collapse occurred due to compressive failures of the facings in the highly stressed edge regions without severe influence from stress concentrations at load introduction and edge supports.     

Some factors affecting enantiomeric impurity determination by capillary electrophoresis using ultraviolet and laser-induced fluorescence detection.

The key factors influencing enantiomer trace determination were investigated; these include resolution capillary diameter, limit of detection, linear range and type of detection. Chiral reagents, (+)- and (-)-1-(9-fluorenyl)ethyl chloroformate (FLEC), were employed as probes to demonstrate the influence of the variables. In order to find the best resolution, separation variables were optimized in both capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) modes by the application of factorial design experiments. A highly efficient chiral separation of the (+/-)-FLEC, derivatized with nonchiral amino acids, was achieved when using gamma-cyclodextrin as the chiral selector. The benefits of using a small diameter capillary for direct determination of both (+) and (-)-FLEC impurity (0.05-0.1% area/area) were demonstrated using UV detection and applying a sample stacking condition. A frequency-doubled argon ion laser (244 nm) was used as light source for laser-induced fluorescence (LIF) detection. Excitation light was provided by means of an optical fiber directed into the Hewlett Packard 3D capillary cartridge. The signals from UV and LIF were monitored simultaneously. The application of LIF detection greatly improved sensitivity and linear range. Further, as a consequence of the increased sensitivity, sample loading could be decreased, which led to an improvement of separation efficiency. Direct determination of 0.005% impurity could be achieved within the linear range.     

Flexure analysis of unsymmetric orthotropic beams with an interlayer

This paper presents a layer-wise stress and deformation analysis of a three-layer beam configuration consisting of two dissimilar orthotropic adherends of different thicknesses that are joined together by a deformable interlayer of finite thickness. Analytical solutions for the case of three-point flexure loading are presented for both compressible and incompressible interlayers. Parametric analysis reveals the influences of asymmetry of moduli and adherend thicknesses, interlayer thickness, and overhang of the beams on the beam compliance. Analytical predictions of beam compliance show very good agreement with finite element results. Experimental measurements of compliance of various unsymmetric beams consisting of aluminum adherends separated by a rubber interlayer were performed in order to validate the analysis. Excellent agreement between measured and predicted compliance values was observed.     

Tubulent Methane/Air Premixed Flame Structure at High Karlovitz Numbers

2D Direct Numerical Simulations of methane/air turbulent premixed flames at initial Karlovitz numbers ranging from 600 to 9500 are performed. Instantaneous results are then extracted and analyzed with a focus on the inner flame structure. Snapshots reveal that the distributed reaction zone regime, theoretically reached around Ka?≈?100, is not attained before Ka?≈?2000. A correction of the definition of Ka is proposed in order to account for gas expansion across the flame, and is found to be consistent with the previous observations. The fuel-consumption zone is shown to be highly affected by turbulence and the characteristics of flames developing at lower Ka cannot be seen: the reaction zone is indeed strongly stretched and curved by intense turbulence leading to the formation of large protruding structures. In addition, the heat release rate layer is found to be broader and more distributed than at lower Ka as small turbulent eddies are able to survive inside it. No local flame quenching is however noticed. A statistical analysis of the distributed flame highlighted three major features characterizing this regime: significant broadening of the whole flame results from the presence of small eddies inside the reaction zone, temperature evolves linearly with respect to the progress variable and minor species peak mass fractions are lower than in a laminar flame. These results have important consequences for turbulent combustion modelling of flames in the distributed combustion regime.     

Nickel complexes of carboxylate-containing polydentate ligands as models for the active site of urease

Two new carboxylate-containing polydentate ligands have been synthesized, the symmetric ligand 2,6-bis[N-(N-(carboxylmethyl)-N-((1-methylimidazol)methyl)amine)methyl]-4-methylphenolate (BCIMP) and the corresponding asymmetric ligand 2-(N-isopropyl-N-((1-aminomethyl)-4-methylphenol (ICIMP). The ligands have been used to prepare model complexes for the active site of the dinuclear nickel enzyme urease, viz. [Ni(2)(BCIMP)Ac(2)](-) (6), [Ni(2)(BCIMP)(Ph(2)Ac)(2)](-) (7), [Ni(2)(ICIMP)(Ph(2)Ac)(2)] (14), [Ni(4)(ICIMP)(2)(Ph(2)Ac)(2)][ClO(4)](2) (15), [Ni(4)(ICIMP)(2)(Ph(2)Ac)(2)(DMF)(2)][ClO(4)](2) (16), and [Ni(4)(ICIMP)(2)(Ph(2)Ac)(2)(urea)(H(2)O)][ClO(4)](2) (17), where the latter complex contains urea coordinated in a unidentate fashion through the carbonyl oxygen. The N(2)O-N(2)O(2) donor set of ICIMP provides a good framework for the preparation of urease models, but in some cases tetranuclear nickel complexes are formed due to coordination of the carboxylate moiety of one dinickel-ICIMP unit to one or both of the nickels of a second Ni(2) unit. Reactivity and kinetics studies of 7 and 15 show that these model complexes catalyze hydrolysis of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) at basic pH. In this assay, complexes based on the asymmetric ligand ICIMP exhibit a significantly faster rate of hydrolysis than the corresponding BCIMP complexes. Magnetic measurements indicate that there are weak antiferromagnetic interactions between the nickel ions in complex 16.     

Spectrophotometric determination of bromide (and iodide) in a flow system after oxidation by peroxodisulphate

The peroxodisulphate method for the determination of bromide has been modified. A flow-injection system for the spectrophotometric finish has been developed and the size of the ion-exchange column in the preconcentration step has been scaled down. The sum of bromate and iodate produced in the oxidation is determined by treating the oxidized sample with iodide in hydrochloric acid. The iodate is separately determined by applying the reaction in acetic acid. The working range of the spectrophotometric finish is 1-15muM and the limit of determination (10 sigma) is 0.7muM for iodate and for iodate plus bromate. The enrichment factor in the preconcentration step is 50, yielding a limit of determination of 15nM for bromide in natural waters. Eighteen samples of water from the Baltic, with salinity ranging from 3 to 33%. have been analysed. A Br/Cl ratio of (1.53 +/- 0.02) x 10(-3) was found. A comparative study of the original and the new preconcentration step has been made with three river waters, rich in humic substances. The results agreed within +/- 1. 5%.     

Validation of a chiral capillary electrochromatographic method for metoprolol on a teicoplanin stationary phase

Summary A chiral capillary electrochromatographic (CEC) method for determination of the enantiomeric purity of either enantiomer of metoprolol has been validated. High resolution and efficiency separations (R _s =2.5 and 80000 plates m⁻¹, respectively) were achieved by use of a teicoplanin chiral stationary phase in the polar organic mode. Method validation showed that detection linearity, robustness, accuracy, and repeatability were adequate. The method was also shown to be sufficiently sensitive for the determination of a minor enantiomer; the limit of quantitation (LOQ) was determined to be 0.09% of the peak area of the enantiomer under investigation. A similar commercial column was subsequently evaluated by use of the validated method and found to yield results for metoprolol comparable with those obtained on the homepacked columns. Acceptable separations on this commercial column were also obtained for other β-blocking drugs; those for alprenolol were particularly noteworthy (R _S =3.8 and 265000 plates m⁻¹).