Showing papers by "Wrocław University of Technology published in 1979"
85 citations
TL;DR: In this article, an analysis of the critical conditions of thermal explosion based on bifurcation theory for nonlinear elliptic equations is presented, where it has been proved that the value of the Frank-Kamenetsky parameter δ equals the principal eigenvalue of the equation of heat conduction linearized about the point of bifury of the solution u(δ), which correspond to self-ignition and extinction points.
56 citations
TL;DR: In this article, the dependence of the resistivity and temperature coefficient of resistivity (TCR) of TiN x films on nitrogen pressure was described, and the influence of aging temperature up to 573 K on the resistance changes were shown.
28 citations
TL;DR: Haemolymph of fully grown larvae of Galleria mellonella was chromatographed on Sephadex G-200 and the column eluate assayed for hydrolytic activity and juvenile hormone (JH) binding and the binding protected JH against most of the blood esterases.
27 citations
TL;DR: In this article, experimental data for the dielectric properties of thin ytterbium oxide (Yb2O3) films deposited in MIM structures were obtained by reactive vacuum evaporation using an electron beam.
25 citations
TL;DR: In this paper, an experimental study on the continuous flow, foam fractionation of cyanide complex anions is presented, and selectivity coefficients were determined for Zn(CN)4 2 vs I− equal to 8.86.
Abstract: An experimental study is presented on the continuous flow, foam fractionation of cyanide complex anions. Zn(CN)4 2-, Cd(CN)4 2-, and Hg(CN)4 2- form 7.5 × 10−6 to 1.5 × 10−5 M aqueous solutions with the quaternary ammonium surfactant, hexadecyltrimethylammonium iodide. The selectivity coefficients were determined for Zn(CN)4 2- vs I− equal to 8.86. for Cd(CN)4 2- vs I− equal to 21.79 and for Hg(CN)4 2- vs I− equal to 25.12. The surfactant ion-exchange reaction with the studied complex ions was also suggested.
18 citations
TL;DR: In this paper, an outline of a hydrometallurgical method employed for the processing of a copper sulphide concentrate is presented, which consists in leaching the concentrate with acid ferric sulphate solution, followed by electrolysis of the copper with simultaneous anodic regeneration of the leaching agent in electrolysers with diaphragms.
17 citations
TL;DR: In this paper, the reduction of (±)-l-(2',2',3'-trimethylcyclopent-3'-en-l'-yl)-propan-2-one by Rhodotorula mucilaginosa was investigated.
14 citations
TL;DR: The porosity of suspension copolymers of methacrylic acid (MA) and divinylbenzene (DVB) has been studied in this article, where copolymer structures are composed of microgels interconnected into a rigid skeleton-like structure.
Abstract: The porosity of suspension copolymers of methacrylic acid (MA) and divinylbenzene (DVB) has been studied. The copolymers were prepared both directly from monomer blends and with toluene or n-octane as inert diluents. The pore volume and radii of pores were larger for copolymers containing 5.0% of DVB than those for copolymers containing 9.1% of DVB. The volume and radii of pores increased with increasing diluent content, but the effect of n-octane was more pronounced than that of toluene. Based on considerations of monomer reactivities and copolymer-diluent and copolymer-unreacted monomer interactions, the following model of structure of MA and DVB copolymers has been proposed: The copolymers are composed of microgels interconnected into a rigid skeletonlike structure, surrounded by lightly crosslinked and unentangled poly(methacrylic acid) chains.
13 citations
TL;DR: The compatibility and mechanical properties of poly(vinyl chloride) (PVC) and thermoplastic polyurethane (PU) are described in this paper, where the compatibility has been estimated using a variety of methods including the measurements of viscosity of polymer solutions, comparison of solubility parameters of PVC and PU, sorption and dynamic mechanical testing.
Abstract: The compatibility and mechanical properties of poly(vinyl chloride) (PVC) and thermoplastic polyurethane (PU) are described in this paper. The compatibility has been estimated using a variety of methods including the measurements of viscosity of polymer solutions, comparison of solubility parameters of PVC and PU, sorption and dynamic mechanical testing. The solubility parameters were taken for calculation of heats of mixing. From a study of the sorption of organic solvent vapour by the investigated polymers and their mixtures, the Gibbs free energies of mixing for polymer-solvent systems were calculated and next the free energy of mixing of two polymers. Blends of PVC with PU are shown to the incompatible. With increasing PU content in the blends impact strength was increased but tensile strength at the breaking point was decreased.
Es wurden Untersuchungen der Mischbarkeit und der mechanischen Eigenschaften von PVC und thermoplastischen Polyurethanen beschrieben. Die Mischbarkeit wurde mit verschiedenen Methoden, wie Messung der Viskositat der Polymerlosungen, Vergleich der Loslichkeitsparameter von PVC und PU, Messung der Sorption und Messung der dynamisch-mechanischen Eigenschaften, abgeschatzt. Die Loslichkeitsparameter wurden zur Berechnung der Mischungswarme benutzt. Anhand der Dampfsorptionsisothermen der organischen Losungsmittel durch Polymere wurde die beim Mischen eingetretene Anderung der freien Energie nach Gibbs berechnet. Es wurde nachgewiesen, das PVC/PU Systeme nicht mischbar sind. Mit steigendem PU-Gehalt in der Mischung nimmt die Kerbschlagfestigkeit zu, wahrend gleichzeitig die Zugfestigkeit abnimmt.
13 citations
TL;DR: In this paper, quasilinear absorption, fluorescence and phosphorescence spectra of 7,8,8a,9,10,10c-hexahydrohexahelicene (HHHL) were obtained in a polycrystalline n-pentane matrix at 77 K.
TL;DR: In this article, the absorption spectra of 2-phenyl-5,6-benzoxalene (PhBO), 1,2-5-6-dibenzoxalenes (DBO), 3-phyl-1, 2-6, 6-dioxalene, and 3-PhDioxalenes were examined in liquid solutions and in Shpolskii matrices at 77 K.
TL;DR: Aminobenzaldehyde and Aminoacetophenone reagieren in Gegenwart von tertiaren Aminen, z. B. Pyridin or Triethylamin, with Alkylchloroformiaten and Alkylisocyanaten zu den entsprechenden N-(Formylphenyl)- and N-(Acetophenyl)-Derivaten des Harnstoffs 2a-p bzw.
Abstract: Synthese von N-(Formylphenyl)- und N-(Acetophenyl) Derivaten des Harnstoffs und der Carbaminsaure
Aminobenzaldehyde und Aminoacetophenone reagieren in Gegenwart von tertiaren Aminen, z. B. Pyridin oder Triethylamin, mit Alkylchloroformiaten und Alkylisocyanaten zu den entsprechenden N-(Formylphenyl)- und N-(Acetophenyl)-Derivaten des Harnstoffs 2a–p bzw. der Carbaminsaure 1a–u. Aminobenzaldehyde und Aminoacetophenone reagieren nicht mit N,N-Dialkylcarbamoylchloriden.
TL;DR: A model of information retrieval system based on thesaurus with weights is described, with emphasis onclusiveness and two other fundamental properties of the considered system are given.
Abstract: This paper describes a model of information retrieval system based on thesaurus with weights. Definitions of the following terms: thesaurus, document description, information query, similarity of queries and descriptions of documents, similarity measure and accuracy of response are given. Inclusiveness and two other fundamental properties of the considered system are given.
TL;DR: In this paper, the effect of the number of spacer insulators on the breakdown voltage of a cylindrical electrode system with a variable number of spacers was investigated and it was shown that the effect was much greater than could be predicted when the normal distribution of the flashover voltages of a single insulator was assumed.
Abstract: It was shown that when extended high voltage vacuum insulation is being considered, the effect of the number of spacer insulators on the breakdown voltage of the system has to be taken into account. Two cylindrical electrode systems with a variable number of spacers were investigated. A very distinct decrease of the breakdown voltage with the increase in the number of insulators was noted. This effect was much greater than could be predicted when the normal distribution of the flashover voltages of a single insulator was assumed. A much better approximation was obtained when the Weibull distribution was used.
TL;DR: The thermodynamic activity of LiReO4 was determined by mass spectrometry at 833 K in this paper, where the authors showed that within the composition range 0.3 < xLiReo4 < 1, the activity coefficient was −2.744 + 3.176 −1.786.
Abstract: The thermodynamic activity of LiReO4 in the LiReO4-CsReO4 system was determined by mass spectrometry at 833 K. Within the composition range 0.3 < xLiReo4 < 1 the activity coefficient of LiReO4 may be expressed by the relation: ln γLiReO4 = −2.744 (1−xLiReO4)2 + 3.176 (1 −xLiReO4)3 −1.786 (1−xLiReO4)4 The compounds LiReO4, CsReO4, (LiReO4)2, (CsReO4)2 and LiCs(ReO4)2 were found to appear in the gas phase.
TL;DR: In this paper, a new method of preparation of carboxyl cation exchangers directly from methacrylic acid and divinylbenzene is described, using a suspension technique with a concentrated aqueous calcium chloride solution as the water phase.
Abstract: A new method of preparation of carboxyl cation exchangers directly from methacrylic acid and divinylbenzene is described. A suspension technique with a concentrated aqueous calcium chloride solution as the water phase was used. n-Octane and toluene were inert diluents of the monomers. The copolymers obtained have high ion-exchange capacity (9.6–10.6 mequ./g) and porous structure.
TL;DR: Anion exchange equilibria on benzyltrimethylammonium resins are studied on solvent-modified copolymer matrices prepared from styrene-divinylbenzene suspension copolymers obtained in the presence of a series of unbranched alkanes (C7 C16) and toluene as mentioned in this paper.
Abstract: Anion exchange equilibria on benzyltrimethylammonium resins are studied on solvent-modified copolymer matrices prepared from styrene-divinylbenzene suspension copolymers obtained in the presence of a series of unbranched alkanes (C7 C16) and toluene. Equilibria involving the exchange of chloride anions for bromide, iodide and perchlorate in dilute 0,01 M aqueous solutions were determined by the limited batch technique. It is found that the structure of the copolymer depends strongly on the interaction of an inert solvent with the copolymer during its formation. This structure affects the hydration of the functional groups and counter-ions in the gel phase and consequently brings about a variation of the selectivity of the resin.
TL;DR: Extraction equilibria in the MnCl2NH4Cl capric acid (C9H19COOH.)CCl4 system were examined in this paper.
TL;DR: Property and operations on inverted files, which are used in system based on thesaurus with weights, are studied in this paper.
Abstract: The inverted file structure is often used to organize data in the information retrieval system. When the hierarchy relation on the set descriptors and weights of descriptors in document description would be taken into account, the conventional concept of the inverted file may be extended. Properties and operations on inverted files, which are used in system based on thesaurus with weights, are studied in this paper.
TL;DR: Several β-haloethylbenzyl ethers were prepared with satisfactory yields by the reaction of ethylene carbonate with benzyl halides in the presence of quaternary ammonium salts as catalysts as mentioned in this paper.
TL;DR: In this paper, a sliding bearing material based on rubber filled with different graphites was assessed against stainless steels of various structures under conditions of water lubrication in an Amsler machine.
TL;DR: In this paper, the results of magnetic and spectroscopic studies of complexes of cobalt(II) of the CoX2L2 type where X Cl, Br, I and L ǫ (C2H5)3PO are reported.
TL;DR: In this paper, the crosslinking density and thermal properties of peroxide-crosslinked low-molecular-weight polybutadiene and its modification products with maleic anhydride were studied.
Abstract: The crosslinking density and thermal properties of peroxide-crosslinked low-molecular-weight polybutadiene and its modification products with maleic anhydride were studied. It was shown that the Flory-Rehner equation may be used for describing the equilibrium swelling of the studied systems. The molecular weight between crosslinks calculated from this equation has values from 117 to 216. It was found thermogravimetrically that the thermal stability of modified polybutadiene is lower than the unmodified material. The thermal destruction of the polymers studied is a step-by-step reaction, the first being of zero order, with activation energy of 76.6–112.6 kJ/mole, the second, a first-order reaction with an Ea of 286.8–363.4 kJ/mole.
TL;DR: In this paper, the possible application of epitaxial graded-gap semiconductor layers as broad range photoconductive detectors is discussed, and a simple theoretical model is proposed to evaluate the performance of these layers.
TL;DR: In this paper, the authors used the equation of the thermal decomposition of the residue remaining after vacuum-distillation of Romashkino crude oil to investigate the kinetics of the process.
Abstract: The equation\(\frac{{d\alpha }}{{\alpha ^p (1 - \alpha )^q }} = kdt\) was used for an investigation of the mathematical description of the kinetics of the thermal decomposition of the residue remaining after vacuum-distillation of Romashkino crude oil.
TL;DR: In this article, the 13C n.m.r. spectra of dibenzothiophene and benzothiopane have been analyzed, showing that the carbons which are common to both the thiophenes and benzene rings show somewhat lower chemical shifts if compared with benzophane.
Abstract: The 13C n. m. r. spectra of benzothiophene and dibenzothiophene, not mentioned so far in literature are presented. The presence of six signals in the 13C {1H } n, m.r. dibenzothiophene spectrum confirms the symmetry of its electronic structure and magnetic effects and indicates the molecule to be flat. In the case of dibenzothiophene the carbons which are common to both the thiophene and benzene rings show somewhat lower chemical shifts if compared with benzothiophene.
TL;DR: In this article, the velocity of a water jet can be increased when the jet impacts a target material or another waterjet, and a theory describing such augmentation in terms of velocity, mass, and energy change is considered.
Abstract: The velocity of a waterjet can be increased when the jet impacts a target material or another waterjet. A theory describing such augmentation in terms of velocity, mass, and energy change is considered. The phenomenon is sensitive to jet structure and the jet velocity profile. Jet velocity profiles do not remain constant over great distances from the nozzle, and ultimately disrupt into droplets. Within the droplet the profile is more regular and the velocity constant. The theory is extended to cover the case of droplet collisions, and experimental evidence of jet augmentation and its effects is presented.
TL;DR: The Bu4N[Cr2H(CO)10] species reacts with hydrogen chloride in methanol to produce Bu4H[Cr(CO)]5Cl.
Abstract: The Bu4N[Cr2H(CO)10] species reacts with hydrogen chloride in methanol to produce Bu4N[Cr(CO)5Cl]. Analogous reactions using the complex K(phen)3Cr2H(CO)10 and K(bpy)2Cr2H(CO)10 salts (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) give the new (phen)2H[Cr2H(CO)10], phenH[Cr2H(CO)10], (phenH)2(Cl)[Cr2H(CO)10], and bpyH[Cr2H(CO)10] derivatives respectively.