Showing papers by "Warsaw University of Technology published in 1980"
TL;DR: Addition of stannous chloride as labilizing agent makes possible a group separation of platinum metals (except osmium) in 1,2-dichloroethane from hydrochloric acid medium.
66 citations
TL;DR: The well-known industrial applications of sulfuric acid have made the oxidation of SO2 to SO3 a process of paramount practical importance as discussed by the authors, and vanadium catalysts are commonly used to catalyze the oxidation.
Abstract: The well-known industrial applications of sulfuric acid have made the oxidation of SO2 to SO3 a process of paramount practical importance. Nowadays vanadium catalysts are commonly used to catalyze the oxidation. Platinum and iron oxide catalysts, formerly employed in industrial practice, are no longer used.
44 citations
TL;DR: In this article, the relationship between magnetic flux density B, and stress σ in ferrites is presented, and it is shown that the position of the Villari point and piezomagnetic sensitivity depend on the same properties of a material as those governing the B (H ) relation.
33 citations
01 Jan 1980
28 citations
TL;DR: In this paper, high temperature stress-strain data were obtained for type 310 austenitic steel with grain sizes of 1 and 63 μm and the data were fitted to the equation σ = σ y + A ϵ 1 2 where σy is defined by the Hall-Petch relation.
25 citations
TL;DR: In this paper, the influence of Lewis acidity of homogeneous organozinc catalyst RZnEt on monomer distribution in maleic anhydride-propylene oxide copolymers produced by this catalyst has been investigated.
Abstract: The influence of Lewis acidity of homogeneous organozinc catalyst RZnEt (R=C2H5-, CH3O-, CH3COO-, 2-CH3OC6H4O-,3-CH3 OC6H4O- and CH3COCH=C(CH3)O-) on monomer distribution in maleic anhydride-propylene oxide copolymers produced by this catalyst has been investigated. It was found that increasing the acidity (electron-accepting properties) of the Zn atom in the catalyst molecule caused an increase in the number of propylene oxide units in the obtained copolymers and a decrease of their average molecular weight.
24 citations
TL;DR: In this paper, the transformation of generalized radiance by space-invariant linear systems based on Walther's second definition is analyzed, and the transfer function for a generalized radiances function is introduced.
Abstract: The transformation of generalized radiance by space-invariant linear systems, based on Walther’s second definition is analyzed. The transfer function for a generalized radiance function is introduced. Its form in the case of quasihomogeneous sources is discussed on the basis of two important examples: free space and an isoplanatic optical system.
22 citations
21 citations
TL;DR: The sensitivity of DSC-traces to controlled aging in successive heating/cooling cycles within the glass transition region was studied in this article, where the effects of cooling rate both of the melt and of the supercooled liquid, as well as of the heating rate, were considered.
Abstract: The sensitivity of DSC-traces to controlled ageing in successive heating/cooling cycles within the glass transition region was studied. The effects of cooling rate both of the melt and of the supercooled liquid, as well as of the heating rate, were considered. It was concluded that within the transformation region the cooling rate of supercooled liquid exerts the predominant effect on the reproducibility of the DSC-curves. It was demonstrated that the thermal history of a sample during glass formation may be erased by only one heating/cooling cycle within the transformation region.
21 citations
TL;DR: In this article, the course of thermal decomposition of basic aluminium ammonium sulfate was investigated and temperature ranges were established in which dehydration of the compound and liberation of ammonia and sulfur oxides take place.
Abstract: The course of thermal decomposition of basic aluminium ammonium sulfate was investigated. Temperature ranges were established in which dehydration of the compound and liberation of ammonia and sulfur oxides take place. The presented scheme of thermal dissociation of the basic salt was based on the determination of the solid and gaseous products of the reaction.
20 citations
TL;DR: In this article, the first results of studies on crystallization and domain structure of a new ferromagnetic amorphous alloy Co90Zr10 were obtained by the "piston and anvil" method with 20 to 45 at% of Co and 90 at % of Co.
Abstract: The paper presents the first results of studies on crystallization and domain structure of a new ferromagnetic amorphous alloy Co90Zr10. Amorphous Co-Zr alloys were obtained by the ″piston and anvil″ method with 20 to 45 at% of Co and 90 at% of Co. Crystallization of Co90Zr10 was studied by X-ray diffraction and differential calorimetry, as well as by transmission electron microscopy (TEM) with simultaneous heating of the material. Domain structure in the amorphous phase was investigated by the method of Lorentz. The types of structures occurring were described, domain wall widths were calculated, and the direction of changes in the parameters of the magnetic structure — caused by annealing and phase transformation — was suggested.
TL;DR: Me 2 (MeCC) 2 Alm (M = Li, Na) and Me 2 (me 3 CC ǫ c) 2 AlLi were synthesized, and found to form stable 1 : 1 complexes with 1,4-dioxane as mentioned in this paper.
TL;DR: In this paper, a simple double exposure technique was proposed for making binary amplitude gratings with preset opening ratio, where the Ronchi type master ruling was imaged onto the photographic plate by a laser projection system.
Abstract: A simple double exposure technique is proposed for making binary amplitude gratings with preset opening ratio. Commercially available Ronchi type master ruling is imaged onto the photographic plate by a laser projection system. The controlled lateral displacement of the ruling or the photographic plate between two exposures results in the composite grating with the required opening ratio. A zoom-effect spherical beam projection system is suggested for producing binary gratings with continuously variable period.
TL;DR: The acidity and catalytic activity of alumina doped with AlCl3, CH3AlCl2, PCl5, Pcl3, I2, Cl2 and H2PO3F were studied.
Abstract: The acidity and catalytic activity of alumina doped with AlCl3, CH3AlCl2, PCl5, PCl3, I2, Cl2 and H2PO3F were studied. Vapors of AlCl3 and CH3AlCl2 induce superacid sites in alumina, whereas PCl3 and PCl5 produce less acidic systems, which nevertheless catalyze the skeletal isomerization of alkenes. The modification of Al2O3 with other specified compounds affects only slightly the acidity and catalytic activity of alumina.
TL;DR: In this article, the authors studied fatigue crack growth retardation under stress spectra with constant amplitude and variable mean stress, respectively, and the best correlation was obtained between monotonic plane stress plastic zone size 2ry and Δa∗.
TL;DR: A new approach for specifying structural information in volume holography, using a grating vector uncertainty relation and a modified Ewald's construction, is proposed and the optimization of the Shannon number of an image is given.
Abstract: A new approach for specifying structural information in volume holography, using a grating vector uncertainty relation and a modified Ewald's construction, is proposed and the optimization of the Shannon number of an image is given.
TL;DR: In this article, the correlation between the degree of negativity of the temperature coefficient of resistivity and the stability of amorphous alloys was observed, indicating that β may be treated as a measure of the structural changes occuring during crystallization.
Abstract: Electrical resistivity and magnetic susceptibility of amorphous NixZr1−x alloys obtained by the “melt spinning” method have been measured in order to study crystallization kinetics. The correlation between the degree of negativity of the temperature coefficient of resistivity and the stability of amorphous alloys was observed. The studied relation between stability and the coefficient\(\beta = \left( {\frac{{\varrho _a }}{{\varrho _c }} - 1} \right)_{T_c }\) indicated that β may be treated as a measure of the structural changes occuring during crystallization.
TL;DR: A description of the hierarchic decomposition method (i.e. multiple decomposition of a decomposed network) which can be applied in computer analysis of electronic networks is given and a new universal algorithm for generation of k-trees is presented.
Abstract: SUMMARY This paper concerns a new approach to the topological analysis of linear networks. It gives a description of the hierarchic decomposition method (i.e. multiple decomposition of a decomposed network) which can be applied in computer analysis of electronic networks. A new universal algorithm for generation of k-trees is presented. For many years topological methods have been used to analyse very small networks only. This is a result of a very fast rise of the number of expressions in the topological formula for the determinant of the network matrixr with the growth of the network size. This remark concerns both linear and flow graphs. Generally known computer programs of topological analysis (for example SNAP, NASAP, TAPLAN) allow analysis of networks of up to 30 nodes (practically, 10 nodes and 20 branches'). The difficulties mentioned above have brought about a decrease in the interest in topological methods. The rapid development of numerical methods of solving large systems of equations described by sparse matrices of coefficients, has resulted in a decrease in the competitiveness of topological methods in relation to numerical methods. The elaboration of a method and a program of topological analysis by a direct decomposition method (see Reference 3, program ADEN), has allowed analysis of networks of up to 50 nodes. However, this method has many significant restrictions, and it can hardly be considered convenient for the user. A brief description of the method and algorithms of topological analysis by the so-called hierarchic decomposition method will be presented in this paper. Some results of the hierarchic decomposition method are presented in Reference 4.
TL;DR: The steric properties of the amines determine whether a complex is formed and at which molar ratio as mentioned in this paper, and the properties of amines are used to determine whether or not a complex can be formed.
01 Apr 1980
TL;DR: In this article, a new approach to the topological analysis of linear networks is proposed, called hierarchic decomposition, which can be applied in computer analysis of networks, and it is shown that this method in computer applications considerably reduces the number of operations needed, and thus the computer time.
Abstract: The paper concerns a new approach to the topological analysis of linear networks. It gives a brief description of the hierarchic decomposition method (i.e. multiple decomposition of a decomposed network) which can be applied in computer analysis of networks. It is shown that this method in computer applications considerably reduces the number of operations needed, and thus the computer time. The applications of the method to the analysis of signal-flow graphs have been pointed out. The algorithms of analysis, and some advantages of this method, are described briefly at the end of the paper.
TL;DR: In this paper, the influence of oxygen on the concentration of perylene cation radicals on the surface of alumina was traced by means of ESR, and the acidity of the alumina centers which causes the perylene conversion is in the range of −3.0 ⩾ Ho⩾ −5.6 or higher.
01 Sep 1980
TL;DR: This paper presents a sound foundations for studying the concurrency relation in the case of the whole class of condition/event nets and presents a formalization of decomposition of nets into indivisible sequential components.
Abstract: We have attempted to present a formalization of decomposition of nets into indivisible sequential components and to investigate different notions of concurrency. We feel that this paper presents a sound foundations for studying the concurrency relation in the case of the whole class of condition/event nets. All proofs will be published soon.
TL;DR: In this article, the He(I) photoelectron (PE) spectra of CpBeX (X = CH 3 (I), C 2 H (II), C 3 H 3 (III), Cl (IV) Br (V)) have been recorded.
TL;DR: In this article, the inner structure of a unidirectional composite was approximated by symmetric, rectangular arrangement of fibers, and the composite thermal con ductivity was calculated with the use of different theoretical methods and compared to experimental data obtained from a model of the composite.
Abstract: The effective thermal conductivity of a unidirectional composite was determined. Inner structure of the composite was approximated by symmetric, rectangular arrangement of fibers. The composite thermal con ductivity was calculated with the use of different theoretical methods and compared to experimental data obtained from a model of the composite and the composite itself. Good agreement was found between theory and experiment. Temperature fields in the composite were also calculated. The results of the effective thermal conductivity occurred to be lower than the analogical values obtained by Adams and Doner. It was found that for isotropic composite having up to 50% fiber volume fraction, Hashin and Rosen's formula for "random arrangement" of fibers could be successfully used. Two pairs of bounds on the composite thermal conductivity were studied. Each of them was found to be narrower for different range of fiber volume fraction.
TL;DR: In this article, a complex of tetraalkylaluminoxane with benzylamine and methylamine was synthesized and the structure of the latter was postulated on the basis of 1 H NMR, 13 C NMR and IR spectroscopic studies, and cryoscopic molecular weight measurements.
TL;DR: In this paper, the donor-acceptor properties of catalysts containing different quantities of orthophosphoric acid on γ-alumina were studied and the decrease in N2O decomposition rate was found to be parallel with that of one-electron donor sites.
Abstract: Donor-acceptor properties of catalysts containing different quantities of orthophosphoric acid on γ-alumina were studied. The decrease in N2O decomposition rate was found to be parallel with that of one-electron donor sites. Catalysts containing more than 0.4 mmol H3PO4/g Al2O3 exhibit individual surface properties due to the formation of an aluminium phosphate phase in the surface layer.
22 Apr 1980
TL;DR: It turns out that nets representing sequential systems and processes are atoms of this lattice, and this fact provides the natural way of building nets representing.
Abstract: The paper concerns algebraic properties of Petrinets. A wide class of nets, called simple nets, is introduced and a lattice of these nets is defined. It turns out that nets representing sequential systems and processes are atoms of this lattice, and this fact provides the natural way of building nets representing. concurrent systems as the superposition of nets representing sequential system components.