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Showing papers by "Wrocław University of Technology published in 1997"



Journal ArticleDOI
TL;DR: In this paper, the simultaneous quantification of carbon monoxide and methane in humid air is presented, and the response of a three-sensor array, including an undoped and a platinum doped tin dioxide sensor showing non-ideal selectivity and a humidity sensor is fed into an optimised feed forward back propagation artificial neural network in order to obtain the carbon dioxide and methane concentration as network output.
Abstract: The simultaneous quantification of carbon monoxide and methane in humid air is presented. The response of a three-sensor array, including an undoped and a platinum doped tin dioxide sensor showing non-ideal selectivity and a humidity sensor is fed into an optimised feed forward back propagation artificial neural network in order to obtain the carbon monoxide and methane concentration as network output. The gaseous environments under study were ternary mixtures in the concentration ranges of 0–0.5% methane, 0–1000 ppm carbon monoxide and 0–60% relative humidity at 20°C. The network structure, network output with respect to a priori known test concentrations and the influence of the size of the training data set is discussed.

91 citations


Journal ArticleDOI
TL;DR: For general composite hypotheses, consistency of the data-driven Neyman's test holds at essentially any alternative as discussed by the authors, but the number of components in the smooth test statistic should be chosen well; otherwise, considerable loss of power may occur.
Abstract: In recent years several authors have recommended smooth tests for testing goodness of fit. However, the number of components in the smooth test statistic should be chosen well; otherwise, considerable loss of power may occur. Schwarz's selection rule provides one such good choice. Earlier results on simple null hypotheses are extended here to composite hypotheses, which tend to be of more practical interest. For general composite hypotheses, consistency of the data-driven smooth tests holds at essentially any alternative. Monte Carlo experiments on testing exponentiality and normality show that the data-driven version of Neyman's test compares well to other, even specialized, tests over a wide range of alternatives.

86 citations


Journal ArticleDOI
TL;DR: In this paper, the authors described the method of direct convertion of aluminium and its alloys chips into final products, and the chips were comminuted in cutting device, and for the future processing the granulated chips larger than 5 mm in length were eliminated.

83 citations


Journal ArticleDOI
TL;DR: This paper proved that the Banzhaf value is a unique symmetric solution having the dummy player property, the marginal contributions property introduced by Young (1985), and satisfying a very natural reduction axiom of Lehrer (1988).
Abstract: We prove that the Banzhaf value is a unique symmetric solution having the dummy player property, the marginal contributions property introduced by Young (1985) and satisfying a very natural reduction axiom of Lehrer (1988).

81 citations


Journal ArticleDOI
TL;DR: The ability of a wide variety of soil-borne fungal strains to degrade four structurally different com pounds containing PC bonds, namely the naturally occurring amino acid ciliatine, the popular herbicide glyphosate, phosphonoacetic acid and 2-amino-3-phosphonopropionic acid was studied to show that soil fungi may play an important role in the biodegradation of organophosphonates.
Abstract: The ability of a wide variety of soil-borne fungal strains to degrade four structurally different com pounds containing PC bonds, namely the naturally occurring amino acid ciliatine, the popular herbicide glyphosate, phosphonoacetic acid and 2-amino-3-phosphonopropionic acid, was studied in order to show that soil fungi may play an important role in the biodegradation of organophosphonates Most of the strains appeared to utilize ciliatine as the sole source of phosphorus for growth Only a limited number of strains were able to grow on the other phosphonates used in this work The strains of Trichoderma harzianum, Scopulariopsis sp and Aspergillus niger chosen for more detailed study show the ability to degrade ciliatine, glyphosate and also amino(3-methoxyphenyl)mehtylphosphonic acid effectively

79 citations


Journal ArticleDOI
TL;DR: A theory of a piezoelectric axisymmetric bimorph is presented in this paper, where the bending moments and stretching forces produced by voltage are derived, and the results obtained by means of the described theory and numerical methods have been verified experimentally or by comparing them with results obtained analytically for a simple structure.
Abstract: A theory of a piezoelectric axisymmetric bimorph is presented in this paper. Bimorphs are often used as electroacoustic transducers, but their use is much wider. A piezoelectic bimorph consists of two or more layers which are placed asymmetrically to the middle surface of the structure. When voltage is supplied to the bimorph, a bending moment is produced which causes transversal deflections of the structure. Average elastic parameters are calculated. Equations for the calculation of bending moments and stretching forces produced by voltage are derived. When the bimorph is a shell of revolution with any shape of meridian, the derived equations can be solved by numerical methods. The finite-element method (FEM) is applied to solve this problem. The bimorph can also be used as a sensor. A theory of such a sensor is also presented. The results obtained by means of the described theory and numerical methods have been verified experimentally or by comparing them with results obtained analytically for a simple structure. It has been proved theoretically that the electric signal produced by a circular transducer clamped on the outer rim of a piezoelectric disc is equal to zero.

72 citations


Journal ArticleDOI
TL;DR: The fuzzy logic based multi-criteria protective relay for a three-phase power transformer is presented and shows significant gains in both sensitivity and selectivity of the self-organized relay compared with traditional approaches.
Abstract: In the paper the fuzzy logic based multi-criteria protective relay for a three-phase power transformer is presented. Twelve criteria used to stabilize the relay are introduced and integrated by means of multi-objective decision-making methods. The introduced protection scheme contains several internal functions and coefficients which are subject to off-line pre-installation self-setting. Three unique procedures are delivered for self-adjusting the relay, and thus, making it self-organized. The results of testing show significant gains in both sensitivity and selectivity of the self-organized relay compared with traditional approaches.

66 citations


Journal ArticleDOI
TL;DR: Some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.
Abstract: The antioxidant effect of a trihydroxyflavone extract from Scutellaria baicalensis on oxidation induced by ultraviolet light, was studied with phosphatidylcholine liposome membrane. Also, as standards, the antioxidative activity of baicalin, wogonin, baicalein and butylated hydroxytoluene (BHT) was investigated. Comparison of the protective effects of the compounds studied against photoinduced lipid peroxidation in lecithin liposome membranes showed that: (1) the inhibitory effect of those compounds (at 1.2 mol% antioxidant content in liposomes) on TBA reactive materials from lipid peroxidation decreased in the order of baicalin > BHT approximately equal to Scutellaria baicalensis. These were found much greater than wogonin and baicalein; (2) the depressed effect of those compounds (at 1.1 mol% compounds content in liposomes) on the production of conjugated dienes (proportional to oxidation index) could be classified as follows: Scutellaria baicalensis approximately equal to baicalin > BHT, these three were found more active much greater than baicalein and wogonin. Results obtained by ESR measurement confirm that Scutellaria baicalensis extract and the BHT compound significantly depressed the effect of liposome oxidation. It was found that the new trihydroxyflavones of Scutellaria baicalensis, ensured a very satisfactory concentration-dependent protection of the liposome membrane against UV-induced oxidation. These findings suggest that some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases (for example in skin diseases) by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.

58 citations


Journal ArticleDOI
TL;DR: In this article, a revised assignment of the infrared spectra of monomeric 1-methyluracil isolated in Ar and N2 matrices is presented, based on the Hartree-Fock and second order Moller-Plesset perturbation (MP2) methods using the D95V** basis set.

56 citations


Journal ArticleDOI
TL;DR: In this paper, homochiral 1-alkyl-3,4-dihydroxypyrrolidines, (S, S )- and (R, R )- 5 were obtained by cyclization and reduction of both enantiomers of (+)- and (−)-tartaric acid, respectively.
Abstract: Homochiral 1-alkyl-3,4-dihydroxypyrrolidines, ( S , S )- and ( R , R )- 5 were obtained by cyclization and reduction of both enantiomers of (+)- and (−)-tartaric acid, respectively. Also ( S , S )-3,4-dihydroxytetrahydrofurane 6 was prepared from (+)-diethyl tartrate. All these heterocyclic vic -diols underwent twofold Mitsunobu reaction (Ph 3 P/DEAD/HN 3 ) followed by catalytic hydrogenation forming stereospecifically the corresponding primary vicinal diamines ( R , R )-, (S,S)- 2 and (R,R)- 3 . The absolute configuration of diamines 2, 3 was established by the exciton-coupling CD spectra of their N,N′-diphthaloyl derivatives.

Journal ArticleDOI
TL;DR: In this paper, the growth rate of carbide crystals is limited rather by the interface kinetics than by carbon diffusion in the melt as was assumed previously, and the analytical description of experimental data in the light of the crystal growth concept allows us to conclude that carbides grow during infiltration, predominantly at the time of fibre contact with molten aluminium, but not during matrix solidification and its subsequent cooling.
Abstract: New results on the carbide formation in aluminium-carbon fibre composites are reviewed, with their implications for technology, including vacuum infiltration of carbon-fibre preforms with liquid aluminium. The microstructure of infiltrated specimens was studied with the aid of transmission electron microscopy. Most lath-like carbide crystals investigated in this work are twins. Twinning is probably connected with the squeezing stresses during matrix cooling due to a high difference in thermal expansion coefficients of carbide and metal. The analytical description of experimental data in the light of the crystal-growth concept allows us to conclude that carbides grow during infiltration, predominantly at the time of fibre contact with molten aluminium, but not during matrix solidification and its subsequent cooling. The growth rate of carbide crystals is limited rather by the interface kinetics than by carbon diffusion in the melt as was assumed previously. This allows some effective methods of process control to be found, for example, growth step retardation by means of an adsorption-active impurity.

Journal ArticleDOI
TL;DR: In this paper, polymers with various degrees of hydrophobicity, porosity, and polarity were studied for the immobilization of lipase from Candida rugosa, which was carried out via glutaraldehyde chemical binding or by adsorption.

Journal ArticleDOI
TL;DR: The structure of the tetragonal NaBi(MoO4)2 crystal was determined in this paper, where the modified Urey-Bradley force field and potential energy distribution were applied for three molecular models of local disorder.
Abstract: The structure of the tetragonal NaBi(MoO4)2 crystal was determined. The space group is I4=S42 with cell dimensions a=5.267, c=11.565 A and Z=2. The molybdenum atoms occupy two different sites of 4 symmetry. The Na+ and Bi3+ cations are situated on two positions with different occupancy factors and are short-range ordered. The IR and Raman polarized spectra are discussed on the basis of the factor group analysis and phonon calculations. The modified Urey–Bradley force field and potential energy distribution were applied for three molecular models of local disorder. Polarization properties are explained and related to the crystal structure. © 1997 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: The results of an investigation of thick-film humidity sensors based on ceramic materials are discussed in this article, where the role of each part of the sensitive material in the electrical conduction process is determined on the basis of measurements and calculated equivalent circuits.
Abstract: The results of an investigation of thick-film humidity sensors based on ceramic materials are discussed in the paper. Thick-film technology is very promising for the production of low cost sensors based on ceramic materials. The technology gives the possibility for reproducible production of sensors with a defined microstructure, determined porosity and proper structure of grains and grain boundaries. Ceramic sensors have advantages over polymer sensors due to their better thermal stability and resistance to chemicals. Properties of thick-film planar humidity sensors based on - (ZCT) ceramics are presented. The influence of and Si additives, as well as firing temperature, on the sensor characteristics are discussed. Impedance spectroscopy measurements determined the correlation between the technological parameters and the electrical properties of humidity sensors. The role of each part of the sensitive material in the electrical conduction process is determined on the basis of measurements and calculated equivalent circuits. The proposed model describes the frequency characteristics at various relative humidities with very good fit to the experimental data. A new approach to the modelling of the impedance frequency dependence by means of an equivalent circuit yields very promising results for sensors.

Journal ArticleDOI
TL;DR: In this paper, a data-driven version of Neyman's smooth test with k components is proposed, where Schwartz's rule is applied to find a suitable dimension and then the smooth test statistic in the "right" dimension finishes the job.
Abstract: Rao's score statistic is a standard tool for constructing statistical tests.If departures from the null model are described by some k-dimensional exponential family the resulting score test is called also smooth test or Neyman's smooth test with k components. An important practical question in applying a smooth test in the goodness-of-fit problem is how large k should be taken. Since a wrong choice may give a considerable loss of power,it is important to make a careful selection.Renewed research in this area shows that the simple question has no simple deterministic answer. Therefore,edwina introduced,for testing a simple goodness-of-fit hypothesis,a data driven version of Neyman's smooth test. First,Schwarz's rule is applied to find a suitable dimension and then the smooth test statistic in the “right” dimension finishes the job. Simulation results and some theoretical considerations show that this data driven version of smooth tests performs well for a wide range of alternatives,and is competitive with ...

Journal ArticleDOI
TL;DR: In this paper, a method for calculating the solvent effect on the molecular electronic ground-state structure of ions and molecules has been presented, being a modification of the Warshel et al. method.
Abstract: A method for calculation of the solvent effect on the molecular electronic ground-state structure of ions and molecules has been presented. In this method, being a modification of the Warshel et al...

Journal ArticleDOI
TL;DR: In this paper, a new group of anionic surfactants, i.e., sodium cis- and trans-(2-n-alkyl-1,3-dioxan-5-yl)sulfates were obtained.
Abstract: In the reaction of cis- and trans-2-n-alky-5-hydroxyl-1,3-dioxane mixtures with SO3 · pyridine complex, followed by neutralization with sodium hydroxide or sodium carbonate, a new group of anionic surfactants, i.e., sodium cis- and trans-(2-n-alkyl-1,3-dioxan-5-yl)sulfates were obtained. The hydrophobic intermediates used in the sulfation reaction were obtained in high yields from four-component glycerol acetals by the process of transacetalization and selective crystallization of 1,3-dioxane derivatives. The physical data of the new compounds and some of their surface properties, such as critical micelle concentration (CMC), effectiveness of water surface tension reduction πCMC, standard free energies of adsorption and micellization, ΔG ads o and ΔG CMC o , surface excess concentration, ΓCMC, and the surface area demand per molecule, ACMC, were determined. It was shown that the surface activity of the standard anionic surfactant sodium dodecyl sulfate should be similar to the surface activity of sodium (2-n-decyl-1,3-dioxan-5-yl)sulfate.

Journal ArticleDOI
TL;DR: In this paper, the mechanical properties, melt rheology, and morphology of binary blends comprised of two polypropylene (PP) grades and two liquid crystalline polymers (LCP) have been studied.
Abstract: The mechanical properties, melt rheology, and morphology of binary blends comprised of two polypropylene (PP) grades and two liquid crystalline polymers (LCP) have been studied. Compatibilization with polypropylene grafted with maleic anhydride (PP-g-MAH) has been attempted. A moderate increase in the tensile moduli and no enhancements in tensile strength have been revealed. Those findings have been attributed to the morphology of the blends, which is predominantly of the disperse mode. LCP fibers responsible for mechanical reinforcement were only exceptionally evidenced. Discussion of PP-LCP interfacial characteristics with respect to mechanical properties-morphology interrelations allowed evaluation of the compatibilizing efficiency of PP-g-MAH. Factors important for successful reinforcement of PP with LCP have been specified. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 969–980, 1997

Journal ArticleDOI
TL;DR: A simplified analysis of the double-layer electret with a frozen space charge leads to the conclusion that such a structure can show a piezoelectric effect when the elasticity coefficients of the layers differ as discussed by the authors.

Journal ArticleDOI
TL;DR: It was established that, during the process, titanium dioxide anatase is created, Crystallizing in a tetragonal lattice, during exposure of the 316L steel with the titanium dioxide coating, in Ringer's solution, protective properties of this covering improve.

Journal ArticleDOI
24 Dec 1997-Langmuir
TL;DR: In this paper, the adsorption and micellization properties of the azo moiety in the surfactant molecule were studied by means of surface tension and cyclic voltammetric (CV) techniques.
Abstract: The adsorption phenomena and micellization of sodium 4-((4‘-alkylphenyl)azo)benzenesulfonates, CnAzoSO3Na (Cn = C2H5, C4H9, C8H17), and sodium 4-((4‘-alkylphenyl)azo)benzoates, CnAzoCOONa (Cn = C4H9, C8H17), were studied by means of surface tension and cyclic voltammetric (CV) techniques and compared with the respective parameters of the standard sodium alkanesulfonates, sodium alkylbenzenesulfonates, and sodium alkanecarboxylates. The presence of the azobenzene moiety in the surfactant molecule as a link between the hydrophobic tail and the anionic head group improves the surfactant solubility in water and introduces the hydrophobic character comparable to the effect of 8.4 methylene groups of the main alkyl chain in the assumed standards. The hydrophobic nature of both phenylene groups attached to the azo entity depends upon the position of these groups in the hydrophilic/hydrophobic zones.

Journal ArticleDOI
TL;DR: Derivatives of aminomethylenebisphosphonic acids constitute a class of promising herbicides and some of the tested compounds were found to exhibit strong herbicidal properties being equal in activity with the popular herbicide glyphosate as well as parent N-pyridylaminometHyleneph phosphonic acids.
Abstract: Derivatives of aminomethylenebisphosphonic acids constitute a class of promising herbicides. More than 40 N-substituted aminomethylenephosphonic acids were synthesized and evaluated for their herbicidal activity on common cress (Lepidium sativum L.) and cucumber (Cucumis sativus L.). Some of the tested compounds were found to exhibit strong herbicidal properties being equal in activity with the popular herbicide glyphosate as well as parent N-pyridylaminomethylenephosphonic acids. N-Substituted iminodi(methylenephosphonic) acids, which may be considered as close analog of glyphosate, were inactive toward test plants.

Journal ArticleDOI
TL;DR: In this paper, coal-tar pitch at temperatures up to 400°C yielded gases, pyrolysis oils, and high-melting pitches (reaction pitches), which were used as reactive additives for weak-coking coals to improve their coking properties.

Book ChapterDOI
28 Apr 1997
TL;DR: Real industrial processes can never be modelled perfectly as simple as the linear first and second order systems, and may be affected by noise, load disturbance and other ambinent conditions that cause parameter variation and sudden model structural change.
Abstract: Real industrial processes can never be modelled perfectly as simple as the linear first and second order systems. They have such marked characteristics as high-order, dead-time, non-linearity etc., and may be affected by noise, load disturbance and other ambinent conditions that cause parameter variation and sudden model structural change. The existing theories can no longer provide systematic and robust tuning laws for these complex situations. The operator intuitively regulates the executor to control the process by watching the error and the change rate of the error between the system's output and the set-point value. Usually fuzzy control rules are constructed by summarising the manual control experiences of an operator who has been controlling the industrial process skilfully and successfully.

Journal ArticleDOI
TL;DR: The equivalence of both models indicates that variations in the local environment of the relaxing configurational units (parallel channel relaxation) can provide a basis for self-similar relaxation dynamics without the need for hierarchically constrained dynamics (correlated clusters relaxation).
Abstract: The question of the origins of nonexponential relaxation is addressed in terms of the probabilistic approach to relaxation. The interconnection between two differently rooted probabilistic models, i.e., between the parallel channel and the correlated cluster models, is presented. We show that clearly different probabilistic origins yield in both approaches a well-defined class of universally valid two-power-law responses with the stretched-exponential and exponential decay laws as special cases. The equivalence of both models indicates that variations in the local environment of the relaxing configurational units (parallel channel relaxation) can provide a basis for self-similar relaxation dynamics without the need for hierarchically constrained dynamics (correlated clusters relaxation).

Journal ArticleDOI
TL;DR: In this article, free radicals were characterized in petrographic constituents of bituminous coals and in chars from brown coal components by EPR, and the change in free radical concentration on oxidation of humic acid 600 °C char from humodetritous brown coal with gaseous 10% oxygen at 330 °C was evaluated.
Abstract: Free radicals were characterized in petrographic constituents of bituminous coals and in chars from brown coal components by EPR. The change in free radical concentration on oxidation of humic acid 600 °C char from humodetritous brown coal with gaseous 10% oxygen at 330 °C was evaluated. Spin concentration in the petrographic constituents from a bituminous coal increases in the order liptinite < vitrinite ≪ inertinite. Increasing maturity of each petrographic constituent correlates with an increase in spin concentration and decrease in g-value. Heat treatment of brown coal group components (bitumens, cellulose, lignin, humic acids, and residual coal) leads to the formation of free radicals up to a temperature of about 550 °C and to their sharp disappearance at higher temperatures. Strongly marked maxima in the spin concentration of the chars are observed at atomic H/C ratios in the range 0.40−0.42 and O/C ratios in the range 0.08−0.10. Increasing heat treatment temperature causes a steady decrease in g-va...

Journal ArticleDOI
01 Apr 1997-Fuel
TL;DR: In this paper, atmospheric pressure temperature-programmed reduction (AP-TPR) was used to characterize the organic sulfur functionalities of nine coal types, ranging from subbituminous coal to anthracite.

Journal ArticleDOI
TL;DR: An investigation of kinematic singularities of nonredundant robot manipulators, conducted toward describing the kinematics by simple mathematical mod els called normal forms, finds that in a neighborhood of the shoulder and elbow singular configura tions, theKinematics assume a simple quadratic (Morin) form, whereas at the wrist singularity, thekinematics are represented by the hyperbolic normal form.
Abstract: This article is concerned with an investigation of kinematic singularities of nonredundant robot manipulators, conducted toward describing the kinematics by simple mathematical mod els called normal forms. The adopted approach comes from the singularity theory of maps. The analysis is concentrated on kinematic singularities of codimension 1. The kinematics at singular configurations are characterized by a number called the differential degree. It is proved that, if this degree is finite, then the kinematics can be transformed to normal forms called pre-Morin or Morin forms. If the differential degree becomes infinite, the kinematics can be given either the prehyperbolic or the hyperbolic normal form. Special attention has been paid to the kinematics of the Unimation PUMA manipulator. A sin gularity analysis of the PUMA kinematics has shown that in a neighborhood of the shoulder and elbow singular configura tions, the kinematics assume a simple quadratic (Morin) form, whereas at the wrist singularity, the ...

Journal ArticleDOI
TL;DR: In this article, structural features of N-pyridylaminomethylenebisphosphonic acids were used to detect herbicidal effects and showed that they might act as inhibitors of some steps in aromatic amino acid biosynthesis.
Abstract: The herbicidal action of N-pyridylaminomethylenebisphosphonic acids is accompanied by an impairment of anthocyanin biosynthesis. This suggests that they might act as inhibitors of some steps in aromatic amino acid biosynthesis. Herbicidal effects were reversed by aromatic amino acids using both bacterial and plant models, a finding that strongly supports this hypothesis. Structural features of these compounds suggest the sixth enzyme in the shikimate pathway 5-enol-pyruvoylshikimate-3-phosphate (EPSP) synthase as a possible target, since a strong structural similarity exists between aminomethylenebisphosphonic acid and an inhibitor of EPSP synthase, the herbicide glyphosate. This is, however, not the case since they did not act as inhibitors of this enzyme.