Showing papers by "Wrocław University of Technology published in 1983"

Accurate fault impedance locating algorithm

Abstract: Fault resistances affect the accuracy of short-circuit location, when distance to the fault is determined by means of measuring reactance at one end of the transmission line. This is because the current which flows through the fault resistance is slightly shifted in phase with respect to the current measured at the end of the line in question, due to the effect of the prefault load current. As a result, the fault resistance is recognised as an apparent impedance with both resistive and reactive components. The latter produces an error in the fault location, as it affects the measured reactance. The paper presents a simple algorithm which compensates for the error, and makes it possible to locate short circuits accurately; even if fault resistances are comparatively high.

On Flow Shop Scheduling with Release and Due Dates to Minimize Maximum Lateness

Abstract: A branch-and-bound algorithm for a two-machine scheduling problem by Grabowski is generalized to the case of an arbitrary number of machines. The lower bounds are obtained by the relaxation of the capacity constraints on the machines. An approach to strengthen these lower bounds is developed. Computational experience with 6-, 10-, 15-, 20-, 30-, 40-, 50-job problems is presented.

Modified plasma-membrane ATPase in mutants of Saccharomyces cerevisiae.

Abstract: Mutations affecting the plasma membrane ATPase of Saccharomyces cerevisiae were obtained by selecting mutants resistant to Dio-9. In a plasma-membrane-enriched fraction of the mutant MG2130, the ATPase activity was resistant to vanadate (50% inhibition by 26 microM in the mutant compared to 1.3 microM in the parental strain). Several catalytic properties of the membrane-bound ATPase were modified by 60-120% in the mutant which had a higher Km for MgATP and was more heatstable, less sensitive to mercurials, and more stimulated by monovalent cations than the parental type. A single mutation is responsible for the phenotypes of four independent allelic mutants. Resistance to Dio-9 in vivo and resistance to vanadate in vitro segregated together in three tetrads issued from a cross between the wild type and mutant. The mutation is semi-dominant as shown by expression of the mutant phenotype in a heterozygous diploid resulting from the cross between the wild type and mutant. It is concluded that the pma locus, affected by these mutations, is the structural gene either for the 100000-Mr subunit of plasma membrane ATPase or for a protein which tightly controls the conformation of the plasma-membrane ATPase within the membrane.

An Orthogonal Series Estimate of Time-Varying Regression

Abstract: Let (X1,Y1), (X2,Y2),... be independent pairs of random variables according to the modelYn=tn(Xn)R(Xn)+Zn,n=1,2,..., wheretn andR are unknown functions.Zn's are i.i.d. random variables with zero mean and finite variance. The marginal density ofXn is independent ofn. In the paper nonparametric estimates of a nonstationary regression function E{Yn|Xn=x}=tn(x)R(x) are proposed and their asymptotic properties are investigated.

Optimal experiment design for identification of linear distributed-parameter systems: Frequency domain approach

Abstract: In this paper optimality conditions for experiment design are derived. The experiment is planned for identification of linear time invariant distributed-parameter systems. The determinant of the averaged information matrix is expressed in the terms of input spectral density matrix and spatial density of measurements, and then used as a measure of estimation accuracy. Presented results are applied to find optimal sensors positions and input signals in several examples.

The minimum spouting velocity in conical beds

Abstract: A theoretical model, describing the equilibrium of forces resulting from gas flow resistance, bed weight and internal solid friction at the point of the minimum spouting velocity, is proposed. An equation for predicting the minium spouting flow rate has been developed and verified by the experimental data obtained in 8 columns with diameters varying from 0.09 m to 0.9 m. On propose un modele theorique qui decrit l'equilibre des forces resultant de la resistance a l'ecoument du gaz, du froids du lit et de la friction interne des matieres solides au point de vitesse minimale de “spouting”. On a etabli une equation pour prevoir le debit minimal de “spouting” et on la verifiee au moyen de resultats experimentaux obtenus dans 8 colonnes de diametres compris entre 0.09 et 0.9 m.

Hydrodynamics, heat and mass transfer during coating of tablets in a spouted bed

Abstract: The results of experimental investigations on the hydrodynamics of flows through conical beds of tablets are presented. An equation for predicting the minimum spouting flow rate, developed earlier on the basis of the Ergun equation, has been verified applying a known equation for tablets. The results of investigations on fluid-to-particle heat and mass transfer coefficients are in agreement with theoretical values obtained from correlation equations describing drying kinetics. On presente les resultats d'etudes experimentales sur l'hydrodynamique d'ecoulements a travers des lits coniques de comprimes. En introduisant une equation pour les comprimes, on a verifie une equation pour le debit minimal de “spouting”, etablie anterieurement a partir de l'equation d'Ergun. Les resultats des etudes sur les coefficients de transfert de chaleur et de masse fluide-particules, concordent bien avec les valeurs theoriques obtenues a l'aide de correlations qui decrivent la cinetique du sechage.

Chemical structure and surface activity

Abstract: Surface tension isotherms of the individual alkyl monoethers of polyoxyethylene glycols C n H 2 n +1 (OCH 2 CH 2 ) z OH ( n from 4 to 8; z from 1 to 5) at the aqueous solution-air interface have been determined. By using the appropriate multiple regression equations a quantitative correlation has been found between the change of standard free energy of adsorption, Δ G o , and the structure of the studied monoethers and of aliphatic alcohols as well. It has been found that within the studied range of surface tension decrease, π from 0 to 20 mN m −1 , the change of standard free energy of adsorption, Δ G o , for the monoethers cannot be regarded as a sum of increments Δ G o [ X i ] corresponding to the definite fragments, X i , of monoether molecules. It has been shown, that not only methylene groups, -CH 2 -, of the hydrocarbon chain, but the -OCH 2 CH 2 - groups of the polyoxyethylene chain have the hydrophobic character as well. The interaction of both these fragments is statistically significant and has an influence on the total value of Δ G o . However, the hydrophobic character of the -OCH 2 CH 2 - grouping is not constant. For the group of compounds studied it decreases with the increasing length of hydrocarbon chain and with an increase in π. For example, for π = 20 mN m −1 , Δ G o [-OCH 2 CH 2 -] for the series of butyl and octyl derivatives is −0.32 and −0.13 RT , respectively. By assuming a simplified additive model which has been most often used to describe the relationships between Δ G o values and the chemical structure of surfactants at interfaces, we have calculated the Δ G π = 20 o [-CH 2 -] and Δ G π = 20 o [-OCH 2 CH 2 -] values for the monoethers using multiple regression equations. These values are −1.07 and −0.25 RT , respectively. The Δ G π = 20 o [-CH 2 -] value for aliphatic alcohols is −1.29 RT . By comparing the increments Δ G π = 20 o [-OH] for monoethers and alcohols (ΔΔ G π = 20 o [-OH] = −0.5 RT ) it can be seen that the -OH group at the end of the polyoxyethylene chain seems to be less hydrated in the adsorption layer. This is probably caused by the participation of the mentioned hydroxyl group in inter- and intramolecular hydrogen bonds.

Derivation of Theoretical Formulas for Resonance Integrals from Heisenberg Equation of Motion II. Inclusion of Rydberg and/or Inner Atomic Orbitals in the Formalism of NDO-Methods

Abstract: On the basis of the Heisenberg equation of motion and Linderberg-Seamans approximations useful formulas for β-resonance integrals in the NDO-like semiempirical methods have been derived. The case ofs,p-electron elements has been investigated. The possibility of inclusion of Rydberg and/or inner orbitals in the basis set of the valence orbitals has been taken into consideration. The results of the test INDOL/R method calculations of vertical transition energies for H2 and H2O molecules has been presented.

Lipophilic complexones, part 3. Synthesis of polyamines derived from 2-alkyl-1,3-propanediols and 2,2-bis(hydroxymethyl)alkanols

Abstract: Lipophilic di-, tri-, tetra-, and hexaamines were synthesized from 2-alkyl-1,3-propanediols and 2,2-bis(hydroxymethyl)alkanols. The alcohols were converted into the sulfonate esters which were substituted with ethylenediamine or sodium azide. The azides were directly reduced to give amines. Also dioxyethylenated 2-octadecyl-1,3-propanediol yielded the corresponding amine. Some amines were converted into the salicylidene derivatives.

Determination of absolute configuration of optically active 1-aminoalkanephosphonic acids by chemical correlations

Abstract: The absolute configurations of optically active phosphonic analogues of serine, β-chloroalanine, phenylalanine, tyrosine and 2-aziridinephosphonic acid have been established via chemical correlations with phosphonic analogues of alanine or aspartic acid of known configuration.

Investigations of the Influence of Hologram Aberrations on the Light Intensity Distribution in the Image Plane

Abstract: The aim in this paper is to analyse, for the examples chosen, the influence of particular aberrations of the point-object hologram on the light intensity distribution in the plane which is assumed to be the image plane. The numerical method used for calculating the light intensity at any image point is that presented in an earlier paper. The calculations have been carried out for three cases of holographic imaging. The recording and reconstruction geometry has been chosen so that it was possible to examine the influence of the particular aberration on the image quality. The calculated energy distribution in the aberration spots is consistent with those resulting from using third-order aberration theory as well as from ‘ray-tracing’ calculations.

On the problem of optimization of a quality inspection process structure

Abstract: The paper deals with the problem of optimization of a quality inspection process structure. The problem is identified with designing an optimal arrangement of inspection operations in a production process (linkages of the quality inspection process with manufacturing and accessory processes). Three mathematical models for the cases of specialized and versatile inspection stations are formulated. It is shown that the problem can be treated as a particular case of a standard assignment problem. An optimization procedure, grounded on Balas' algorithm, is proposed. A numerical example, based on real data, is given.