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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 177-179 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Dithiole Annelated Crown Compounds
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: There are indications that the chemical reaction involved in bound rubber formation proceeds via a free-radical mechanism for compounds filled with reinforcing hydrated fine-particle silica, as well as in the case of carbon black as filler. The high potential of silica as a rubber reinforcer is indicated by its bound rubber formation. This potential was realized by the extent of filler-polymer interaction developed in silica-filled vulcanizates cured by peroxide and by high-energy radiation, respectively. Both these relatively simple curing systems are postulated to effect crosslink formation via a free-radical mechanism. The value, after cure, of the ratio of the crosslink density of the filled compound to the crosslink density of the respective unfilled compound, η/η0, was taken to be a logical measure of the ability to reinforce. In natural rubber compounds filled with silica (30 vol.), the values of η/η0 obtained were 1.6-1.9 for peroxide-cured material, and 3.6 for radiation-cured material. Comparisons are made with similarly cured HAF black-filled stocks. Sulfur-cured natural rubber stocks filled with HAF black (30 vol.) generally exhibit η/η0 values in the range of 1.5 to 2.0. Comparative effects of antioxidants are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 17 (1986), S. 238-246 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Spannungshypothesen und Werkstoffanstrengung im Hertz'schen KontaktDer Spannungszustand im Halbraum des Hertz'schen Kontaktbereichs kann unter idealisierten Annahmen für verschiedene Geometrien in Abhängigkeit von der Flächenpressung (Normalkraft), der Reibung (Tangentialkraft an der Oberfläche) sowie den Eigenspannungen im Werkstoff berechnet werden.Aus den Koordinatenspannungen lassen sich Vergleichsspannungen nach verschiedenen Anstrengungshypothesen (Gestaltänderungsenergiehypothese, Schubspannungshypothese und Wechselschubspannungshypothese) bilden.Untersucht wird die Wirkung von Reibung, Eigenspannungen und Geometrie der Kontaktfläche auf die Vergleichsspannung nach den einzelnen Anstrengungshypothesen. Es erfolgt die Darstellung des Einflusses dieser Parameter auf Ort und Betrag des im Werkstoff auftretenden Vergleichsspannungsmaximums.Anhand dieser Untersuchungen wird deutlich, daß die Gestaltänderungsenergiehypothese bei dynamisch beanspruchten Wälzelementen die Werkstoffanstrengung am besten beschreibt. Die Schubspannungshypothese kann als gute Näherung aufgefaßt werden, während die Wechselschubspannungshypothese nur sehr eingeschränkt aussagefähig ist.
    Notes: Using idealised assumptions, the stress condition in the semi infinite body of the Hertzian contact region can be calculated for various geometries as a function of the surface pressure (normal force), the friction (tangential force at the surface) and the residual stresses in the material.Equivalent stresses can be formed from the coordinate stresses using various stress hypotheses (distortion energy hypothesis, shear stress hypothesis and alternating shear stress hypothesis).The effects of friction, residual stresses and contact geometry on the location and magnitude of the equivalent stresses appearing in the material have been investigated, the stress hypotheses being evaluated in terms of the extent to which they take account of these effects in an appropriate form.These investigations show clearly that the distortion energy hypothesis is the best representation of the extent of material stress in the case of dynamically loaded rolling elements. The shear stress hypothesis can be considered as a good approximation whereas the alternating shear stress hypothesis is only capable of providing useful conclusions to a limited extent.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 48 (1893), S. 1-16 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1533-1550 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For small strains Lodge's rubberlike-liquid theory is a valid description of the rheological behaviour of polymer melts, but at higher strains the theory fails: The phenomenon of shear thinning which is characteristic for the shear flow of nearly all polymer liquids is not explained, and in elongation the deviation of the experimental data from the predictions of Lodge's theory reflect also a flow thinning, and not a strain hardening in spite of the pronounced S-shape of the stress-strain diagrams. Comparing the measured stress growth and stress relaxation data with the predictions of the theory, it must be concluded that the temporary physical network structure of the polymer melt is destroyed increasingly with the magnitude of the deformation. Hence, the number of entanglements decreases with increasing strain. For simple shear and uniaxial extension of a well-defined polyethylene melt the strain dependence of the relative entanglement density is discussed. The irreversibility of the disentanglement process of the network is considered.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 538 (1986), S. 177-190 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigation of the Reaction of Sulfur with Sodium Nitrite in DMF, DMSO, and HMPAThe mechanism of the title reaction has been elucidated by VIS/UV, IR, 15N NMR, and ESR spectrometric measurements, gas analysis, and chromatography. The course of the complex reaction and the great number of products  -  nitrous oxide, nitric oxide, sodium thiosulfate, sulfate, polysulfides, polythionates, nitrate  -  can be explained with the assumption that at first perthionitrates NaSxNO2 are formed, which are decomposed either to give dinitrogen monoxide and thiosulfate, or, react with nitrite to yield nitrate and perthionitrite NaS2NO which dissociates reversibly into sodium trisulfide(-I) and nitrogen monoxide. (The details of the two main series of competitive and consecutive reaction steps can be seen from the tabular summary at the end of the text). The characteristic colour change during the reaction from blue-Green to orange-red is due to the formation of the two coloured species: S3- (blue, λmax = 620 nm, g = 2.029) and ONSS- (red, λmax = 448 nm, δ(15N) = 334 ppm, ref. K15NO3).
    Notes: Durch VIS/UV-, IR-, 15N-NMR- und ESR-spektrometrische Messungen, sowie chromatographische und Gas-Analysen ist der Mechanismus der Titelreaktion aufgeklärt worden. Der Verlauf der komplexen Umsetzung und die groβe Anzahl von Produkten  -  Distickstoffoxid, Stickstoffmonoxid, Natriumthiosulfat, Sulfat, Polysulfide, Polythionate, Nitrat  -  können mit der Annahme erklärt werden, daß zunächst Natriumperthionitrate NaSxNO2 entstehen, die sich in Distickstoffoxid und Thiosulfat zersetzen, oder auch mit Nitrit zu Nitrat und Perthionitrit, NaSSNO, reagieren, das reversibel in Stickoxid und Natriumtrisulfid(1 - ) dissoziiert. (Bezüglich der Einzelheiten der konkurrierenden und aufeinander folgenden Reaktionsschritte vgl. Tab. 2.) Der charakteristische Farbwechsel während der Titelreaktion von blau-grün über braun nach orangerot ist auf die Entstehung zweier Farbträger zurückzuführen: S3- (blau, λmax = 620 nm, g = 2,029) und ONSS- (rot, λmax = 448 nm, δ(15N) = 334 ppm, bez. auf K15NO3).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 558 (1988), S. 189-192 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Sulfides with Nitrogen Monoxide in Aqueous SolutionThe title reaction has been reinvestigated by VIS/UV and NMR spectrometric measurements. The formation of N-nitrosohydroxylamine monosulfonate could be confirmed. Moreover we could observe that unstable orange-yellow perthionitrite appears temporarily.
    Notes: Die Titelreaktion ist durch VIS/UV- und NMR-spektrometrische Messungen erneut untersucht worden. Dabei konnte die überraschende Entstehung von N-Nitrosohydroxyl-aminmonosulfonat bestätigt und überdies die vorübergehende Bildung von in Wasser unbeständigem orangegelbem Perthionitrit nachgewiesen werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 24 (1891), S. 4231-4233 
    ISSN: 0365-9496
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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