Showing papers by "Vienna University of Technology published in 1976"

Zur simultanen relativkonduktometrischen Kohlenstoff- und Schwefelbestimmung in Stäuben

Abstract: Die Anwendung der relativkonduktometrischen Methode zur Bestimmung des Kohlenstoff- und Schwefelgehaltes von Stauben kann auf zwei verschiedene Arten, mit unterschiedlicher Aussagekraft, erfolgen: 1. Die Zersetzung der Probe im Sauerstoff — oder Inertgasstrom — erfolgt „rasch“ bei einer Temperatur von 1250° C und ergibt relativkonduktometrisch gemessen den Gesamtgehalt an C und S. 2. Die Zersetzung der Probe erfolgt „langsam“ in einem Zeitraum von 1–2 h in einem temperaturprogrammierten Ofen, wobei bestimmte Verbindungsgruppen nach ihrer Oxidierbarkeit bzw. Zersetzungstemperatur aufgetrennt und als CO2 bzw. SO2 relativkonduktometrisch bestimmt werden. Die temperaturdifferenzierten C- und S-Kurven ermoglichen eine rasche Charakterisierung der verschiedenen Staube.

Unified analysis of static, dynamic and electronic properties of the alkali metals

Abstract: The realization of Harrison's first-principles pseudopotential concept is re-analyzed. It is shown that the most critical and at the same time most fundamental step is the separation of the electronic system into two subsystems, tightly-bound core-electrons and quasi-free valence-electrons. Different varieties of the local statisticalX α-exchange and correlation approximation are used to describe the core-core and valence-core many-body interactions. Many-body effects among the conduction-electrons are taken into account by using different modified forms of the dielectric screening function. The different potentials are applied to a calculation of phonon-dispersion relations and mode-Gruneisen parameters, of the cohesive properties (equilibrium lattice constant, binding energy, compressibility, equation of state), of the crystal structure, the thermodynamic properties, the interionic pair potential and of some electronic properties (liquid resistivity as a function of temperature, Fermi-surface data). It is shown that a careful description of the many-body interactions, both in the formulation of the electron-ion potential and in the screening process, allows a quantitatively accurate unified and fundamental analysis of a wide range of different properties.

NMR-Spektren einiger Benzylidenbarbitursäurederivate

Abstract: The NMR-Spectra of substituted benzylidene barbituric acids, benzylidene dimethylbarbituric acids and some 1,4-and 1,3-cycloaddition products are reported. The signals of the olefinic protons and the N−CH3-signals depend on the conformation of the compounds. The NMR-Spectra of the anions are also given.

Die Kristallstruktur der Verbindung Li 2 ZnGeO 4

Abstract: The crystal structure of dilithiumzine orthogermanate, Li2ZnGeO4, has been determined and refined byFourier syntheses and least-squares, using three dimensional single-crystal data. A finalR-value of 5.7% was obtained. The monoclinic unit cell (Pn−Cs 2) with the dimensionsa=6.40,b=5.45,c=5.04 A and β=90.2° contains two formula units Li2ZnGeO4. The crystal structure is built up by [GeO4] tetrahedra, which are linked together by [LiO4] and [ZnO4] tetrahedra. The average interatomic distances are found to be: Ge−O=1.77, Li−O=2.01 and Zn−O=1.93 A.

Über die Synthese von substituierten 1,3-Dihydro-5-(2-pyridyl)-thieno[2,3—e]-1,4-diazepin-2-onen

Abstract: The preparation of the title substances as well as their chlorination in position 7 and methylation in position 1 are described.

Ion and Electron Flow in Hot-Cathode PIG Sources for Multiply Charged Heavy Ions

Abstract: Calorimetric measurements of the power dissipated at both the anode and the anticathode of a hot-cathode Penning ion source have been made. The analysis leads to the existence of a considerable electron flow from the PIG plasma onto the cathodes. That is in agreement with the electron currents extracted through holes in the cathodes of a hot-cathode PIG source. Neither the measured plasma electron temperature of 0 provide an explanation. Therefore, it is assumed that a fraction of primary electrons is heated by means of nonlinear collective plasma processes. A PIG discharge model involving a peculiar velocity distribution of the ionizing electrons is presented.

Neue Derivate der 2-Acylamino-thiophen-(und-benzo[b]thiophen-)-3-carbonsäure sowie des ([1]Benzo-)Thieno[2,3-d]-pyrimidin-4(3H)-ons

Abstract: The title substances1 and2 were prepared by acylation of the corresponding ethyl 2-amino-thiophene- (or:-4,5,6,7-tetrahydro-benzo[b]thiophene)-3-carboxylates, in some cases followed by reactions introducing a basic substituent.

Redoxkinetik von Metallkomplexen in nichtwäßrigen Lösungen II. Die Reduktion verschiedener Fe(III)‐Solvate mit Fe(II) in Acetonitril

Abstract: Losungen von Eisen(III)-solvaten in Acetonitril enthalten neben [FeL6]3+ auch niedriger koordinierte Komplexe, die um so schneller reduziert werden, je kleiner die Koordinationszahl ist. Die Abhangigkeit des prozentualen Anteils des pentakoordinierten Komplexes von der Donizitat der Liganden beweist, das seine Bildung aus dem Hexasolvat uber zwei Reaktionsschritte erfolgt. Bei gegebener Koordinationszahl sinkt die Reduktionsgeschwindigkeit eines Komplexions mit steigender Donizitat seiner Liganden. Solutions of iron(III)-solvates in acetonitrile contain in addition to the species [FeL6]3+ complexes of lower coordination number. The lower the coordination number the faster is the reduction of the complex. The dependence of the percentage of the pentacoordinate complex on the donicity of the ligands proves that its formation from the hexa-solvate proceeds via two reaction steps. For given coordination number the rate of reduction of a complex ion decreases with increase of the donicity of its ligands.

Zur direkten Nitrierung des Benzimidazolons und der Reduktion einiger dieser Nitrierungsprodukte

Abstract: Different methods of direct nitration led to mono-, di-, tri- and tetranitrobenzimidazolone. Nitration of benzimidazolone with conc. HNO3 in glacial acetic acid and acetic anhydride at 30° gives 5-nitrobenzimidazolone, at 70° dinitrobenzimidazolone. Nitration with fuming HNO3 at 60° gives pure trinitrobenzimidazolone. The tetranitrobenzimidazolone is received by nitration with acetyl nitrate at 70°. Reduction of mono- and dinitrobenzimidazolone to the corresponding amines is best carried out with hyrazine and Raney nickel.

Kräfte zwischen koaxialen Zylinderspulen

Abstract: Mit den Formeln fur die Komponenten des Magnetfeldes einer Zylinderspule werden die auf eine zweite, koaxiale Zylinderspule ausgeubten Krafte berechnet und zwar die auf einen achsenparallelen Streifen des Zylindermantels wirkende langenbezogene Kraft und die Gesamtkraft auf die Spule. Als Anwendungsbeispiele werden die Beziehungen fur die Kraft auf die auserste Windung einer Zylinderspule und fur die Kraft einer unendlich langen Spule auf eine koaxiale Spule abgeleitet.

Verfeinerung der Kristallstruktur von Te2O3(SO4)

Abstract: The crystal structure of ditellurium(IV)-trioxide sulfate, Te2O3(SO4)—space group Pmn21−C 2v 7 ;a=8.879 (2),b=6.936 (2),c=4.646 (4) A,Z=2—has been determined and refined by least-squares, using three-dimensionalX-ray data (1188 independent reflexions) to a final R-value of 6.3%. The crystal structure comprises puckered tellurium(IV)—oxygen layers in which the tellurium atoms are linked together by three oxygen bridges (Te−O 1.907, 1.945, 2.011 A). The SO4 groups are arranged between these layers. Two oxygen atoms of each SO4 group are bonded to two adjacent tellurium atoms of one layer [Te−O(→S) 2.270 A] and the tellurium atoms show a (3+1) coordination. A third oxygen atom of the SO4 group is in weak interaction with two adjacent tellurium atoms of the same layer (Te−O 2.603 A) whereas the fourth oxygen atom has distances of 2.866 A to two adjacent tellurium atoms of the next layer and effects a very weak interaction between the $$_ \propto ^2 Te_2 O_3 - layers.$$

Inflation in Small Countries

Abstract: This volume contains the contributions to the conference “Inflation in Small Countries”, held in Vienna in November 1974. The participants would like to express their appreciation to the Austrian Minister of Finance for having made this conference possible and to the Institute for Advanced Studies in Vienna for their assistance. The selection and treatment of the subjects reflect both the manner of presenting the problem and the state of current inflation-theory. In essence, three fundamental concepts are currently rivalling to explain the inflation: the structural hypothesis, the Phillips curve, and the monetary hypothesis.

Synthesen von 2-Anilinocyclopentanonen

Abstract: The syntheses of the 2-anilinocyclopentanones2 a–2 e in yields about 50% by reaction of 2-chlorocyclopentanone with 4-chloroaniline, N-methyl-4-chloroaniline, α,α,α-trifluoro-3-toluidine, N-methyl-α,α,α-trifluoro-3-toluidine and 3,4,5-trimethoxyaniline, are described.

Lösungsmitteleinfluß auf das Redoxverhalten von Bistriphenylphosphinquecksilber(II)-perchlorat

Abstract: The influence of solvents on the redox behaviour of bistriphenylphosphinomercury perchlorate has been investigated by polarographic, voltammetric and potentiometric methods. The electrode process was found to be reversible in acetonitrile, propylene carbonate, N,N-dimethylformamide and dimethyl sulfoxide. An irreversible process was observed in nitromethane employing the dropping mercury electrode as well as in N,N-dimethylthioformamide and N-methyl-2-thiopyrrolidinone employing the rotating platinum electrode. Half wave potentials and diffusion coefficients have been measured. A linear relationship between theE 1/2 and the donor number (DN) of the solvent has been found for the reversible electrode reactions. Ligand replacement occurs in N,N-dimethylthioformamide and N-methyl-2-thiopyrrolidinone.

Neue Erkenntnisse über den Abbau der Stärke mit Hypochlorit 3. Mikroskopische Charakterisierung oxydierter Stärke

Abstract: New Knowledge on Degradation of Starch by Hypochlorite. Part 3. Microscopic Charakterization of Oxidized Starch The possibility for microscopic characterization of hypochlorite oxidized potato starch was examined. By pre-treatment with methanol a typical appearance as a function of the degree of oxidation was found.

Die Erhöhung der Grundfrequenz und der Beullast von Kreisplatten durch geeignete plastische Verformung

Abstract: Eine Moglichkeit, ohne Mehraufwand an Material oder Verwendung teurerer Werkstoffe das dynamische Verhalten oder die Tragfahigkeit von Bauteilen zu verbessern, wird am Beispiel der Grundfrequenz- und Beullaststeigerung von Kreisplatten durch das Einpragen von geeigneten Eigenspannungszustanden dargelegt. Die Ergebnisse einer Optimierung solcher Eigenspannungsfelder werden dargestellt, und die Moglichkeit der Erzeugung geeigneter Eigenspannungszustande wird an Hand eines Experiments nachgewiesen.

Die Rolle der Wasserstoffbrückenbindung bei der ionenassoziation von Ammoniumsalzen

Abstract: The dissociation constants of quinuclidinium chloride have been determined in dimethylsulfoxide (DMSO), dimethylacetamide (DMA), dimethylformamide (DMF), propanediol-1,2-carbonate (PDC), acetonitrile (AN), nitromethane (NM) and nitrobenzene (NB). The data suggest that the H-atom bonded to the N-atom is sufficiently acidic in order to form H-bridges either with the chloride ion or with solvent molecules. In contrast to the failure of elementary electrostatic models the results have been successfully interpreted by the coordination chemical approach which takes into account the different nucleophilic and electrophilic properties of the solvents.

Das Redoxverhalten des Hexakismethylisonitrilmangan(I)-Ions in Propylencarbonat

Abstract: Employing voltammetric and polarographic methods the hexakismethylisonitrilemanganese(I) [Mn(L)6 +] ion was found to undergo two oxidation steps to hexakismethylisonitrilemanganese(II) and hexakismethylisonitrilemanganese(III) as well as a reduction to the metal. Using bisbiphenylchromium(I) iodide [BBCr(I)I] throughout this study as a reference system cyclic voltammetry yielded a value of 2.29 V for the oxydation Mn(L)6 2+/Mn(L)6 3+ and 1.11 V for the oxydation Mn(L)6 +/Mn(L)6 2+ vs.BBCr(I)I. The half wave potential on the dropping mercury electrode for the oxidation Mn(L)6 +/Mn(L)6 2+ aggreed within the limits of experimental error with the value obtained by cyclic voltammetry, theE 1/2 for the reduction was found to be −1.87 V vs.BBCr(I)I. Large scale electrolysis, coulometry and the rotating platinum electrode were used to learn about the nature of the reaction and the reaction products. 0.1M solutions of tetraethylammonium perchlorate tetrabutylammonium perchlorate and tetraethylammonium nitrate served as supporting electrolytes. The standard rate constant for the reaction Mn(L)6 +/Mn(L)2+ was 1.1·10−2 cm·sec−1 and for the reaction Mn(L)6 2+/Mn(L)6 3+ 4,7·10−3 cm·sec−1. The UV-spectra of Mn(L)6 + and Mn(L)6 2+ were also recorded.

The structure generating function of some families of languages

Abstract: The structure generating function of a language enumerates the number of distinct words contained in the language with respect to their length. Given any language generated unambiguously by a grammar with context-free control language or generated n-unambiguously by a state grammar with context-free control language or generated unambiguously by a tuple grammar with contextfree control language, a method is described which yields a system of equations, whose unique solution is the structure generating function.

Das Magnetfeld eines gleichstromdurchflossenen Torus

Abstract: Es wird das Magnetfeld eines gleichstromdurchflossenen Torus berechnet, wobei fur die Stromdichteverteilung im Inneren des TorusS=S m r m (m ganz) gelten soll. Als Beispiel wird im Fallem=0 und −1 das Magnetfeld im Zentrum des Torus berechnet.

Thin slits: transmission and polarization; comment.

Abstract: Recently Kuttner reported on experiments pertaining to the transmission of thin slits. I would like to point out some misconceptions in his paper. It seems to present problems rather than to solve them. In Ref. 1 data were given on the Fig. 1. Ratio T /T as a function of normalized slit width kd. Full line gives the theoretical results for a slit in an infinitely thin, perfectly conducting plane. The dashed lines are the experimental results of Ref. 2, where the fact that the slit was immersed has been taken into account-by reducing the wavelength cited by a factor of 1.5.

Neue (Hetero-)Triarylmethan-Derivate

Abstract: The following groups of title substances according to general formula I where prepared: substituted α, α-diphenyl-2-thenyl-derivatives (mainly of heterocyclic secondary amines), chlorinated α-phenyl-α-(2-thienyl)-4-pyridinemethanoles and substituted (mainly chlorinated) tri- and tetraphenylmethanes.

Das elektromechanische Verhalten der stromrichtergespeisten Asynchronmaschine

Abstract: Bei Linearisierung der Ausgangsgleichungen durch Beschrankung auf kleine bbweichungen von einem stationaren Ausgangszustand last sich das elektromechanische Verhalten der Asynchronmaschine durch Blockschaltbilder im Sinne der Regelungstechnik sehr anschaulich und ubersichtlich darstellen. Wie bereits eine einfache Naherungslosung zeigt, hat die Maschine eine in erster Linie vom Anfangswert des Quotienten uS0/ωS0 abhangige ausgepragte mechanische Eigenfrequenz, mit der die Drehzahl bei Anderungen der Storgrosen Speisespannung, Speisefrequenz oder Belastungsmoment einschwingt. Genauere Analysen zeigen instabile Betriebsbereiche bei grosen Werten des Ohm'schen Statorwiderstandes sowie stark erhohte Pendelneigung bei bestimmten tieferen Speisefrequenzen. Hohe Drehzahlen sind vom regelungstechnischen Standpunkt selbst bei Feldschwachung unproblematisch.