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  • 1
    Electronic Resource
    Electronic Resource
    Abtragungsraten von Zink bei Gleich- und Wechselstrombelastung (1982)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 542-546 
    Details
    ISSN: 0947-5117
    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: Corrosion losses of zinc under direct and alternating current flow.Investigations have shown that zinc, as a pure bulk material as well as in the form of zinc coatings on earth contacts can be used for draining alternating current. There is no potential shift toward more positive values as e.g. in the case of magnesium under alternating current flow and the corrosion loss of zinc is increased negligibly. When using galvanized sheet iron earth contacts or zinc anodes for draining alternating current rare should be taken to avoid potential values more negative than - 1.5 V when additional cathodic protection is applied. Since zinc is an amphoteric metal, this would give rise to increase material losses because of the sodium hydroxide generated in such condition. The investigations have shown that at potentials, between - 1.1 and 1.5 V zinc loss is considerably reduced. When establishing the potential it should be considered that additional superposition of alternating current may cause the zinc potential to become more negative by approx. up to 0.1 V; this means that the potential should be selected between approx. - 1.3 and 1.4 V.
    Notes: Die Untersuchungen ergaben, daß Zink sowohl als Reinzink als auch als Verzinkung von Bandeisenerdern durchaus zur Ableitung von Wechselstrom eingesetzt werden kann. Eine durch Wechselstrom bedingte Verschiebung des Potentials in positiver Richtung, wie sie bei Magnesium auftritt, ist nicht gegeben. Bei Wechselstrombelastung wird die Abtragungsrate des Zinks nur unwesentlich erhöht.Allerdings ist beim Einsatz sowohl von verzinkten Bandeisenerdern als auch von Zinkanoden zur Ableitung von Wechselströmen darauf zu achten, daß bei zusätzlichem kathodischem Schutz keine Potentialwerte negativer als - 1,5 V eingestellt werden. Anderenfalls besteht die Möglichkeit, da es sich bei Zink um ein amphoteres Metall handelt, daß durch die dann entstehende Natronlauge ein erhöhter Materialabtrag stattfindet. Die Untersuchungen zeigen, daß bei Potentialwerten zwischen - 1,1 V bis - 1,5 V der Zinkabtrag erheblich vermindert wird. Bei Einstellung des Potentials muß berücksichtigt werden, daß durch die zusätzliche Wechselstrom-überlagerung das Zink-Potential bis etwa 0,1 V negativer werden kann, d. h. daß der Potentialwert nur auf ungefähr - 1,3 V bis - 1,4 V eingestellt werden sollte.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19820331003
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  • 2
    Electronic Resource
    Electronic Resource
    Neue Verfahren der IR-freien Potentialmessung beim kathodischen Korrosionsschutz erdverlegter Rohrleitungen (1983)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 34 (1983), S. 230-235 
    Details
    ISSN: 0947-5117
    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: New methods for potential measurement without internal resistance (IR) in cathodic protection of underground pipelinesThe reliability of the cathodic protection depends on whether the potential measurement is free of errors or not. The main source of errors results from voltage drops in the soil. In the case of strongly fluctuating currents the true pipe-to-soil potential can be determined by measuring voltages above the pipe-line and extrapolating these values. This method supposes that the pipe coating has many holidays. The method is not applicable for well coated pipe-lines with the exception of such points where holidays are located.In the case of protected structures with locally different polarisation the off-potentials which normally indicate the true pipe-to-soil potentials can become erroneous due to voltage drops of compensating currents (cell current). Assuming an ideally same distribution of both the protection current and the compensating current the true pipe-to-soil potential can be calculated by measuring the on-and off-potentials and the voltage drop perpendicular to the pipe-line at the soil surface.These relationships can be experimentally verified with an electrolytic cell in the laboratory. In the field, however, deviations from identical distribution of the mentioned currents are possible due to interference of the potential fields of anodes and cathodes. the voltage drops due to compensating currents explain both possible corrosion damage in spite of sufficiently negative values of the off-potential and misinterpretation in the case of hot spot protection. From these results it can be shown that one cannot do away with external probes.
    Notes: Die Sicherheit des kathodischen Korrosionsschutzes ist von der Fehlerfreiheit der Potentialmessung abhängig. Hierbei kommen als Fehler vor allem Ohmsche Spannungsabfälle im Erdboden infrage. Bei stark veränderlichen Strömen kann aus Messungen des Spannungsabfalls über der Rohrleitung das wahre Rohr/Boden-Potential örtlich durch Extrapolation bestimmt werden, wenn die Rohrumhüllung verhältnismäßig viele Fehlstellen enthält. Das Verfahren ist sehr aufwendig und für gut umhüllte Rohrleitungen nicht anwendbar, wenn man von georteten Fehlstellen in der Umhüllung absieht.Bei stark unterschiedlich polarisierten Objekten können die sonst gut verwertbaren Ausschaltpotentiale durch Spannungsabfälle der Ausgleichsströme verfälscht sein. Für eine ideal gleiche Verteilung von Schutz-und Ausgleichsströmen läßt sich mit Hilfe der gemessenen Rohr/Boden-Potentiale und der Potentialdifferenzen senkrecht zur Rohrleitung bei ein- und ausgeschaltetem Schutzstrom das wahre Rohr/Boden-Potential errechnen. Durch Versuche im elektrolytischen Trog konnten diese Zusammenhänge experimentell bewiesen werden. In der Praxis können Abweichungen vom idealen Verhalten auftreten, wenn die Spannungstrichter von Anode und Kathode sich beeinflussen. Die durch Ausgleichsströme verursachten Spannungstrichter erklären mögliche Schäden trotz scheinbar ausreichender negativer Ausschaltpotentialwerte und Fehlaussagen beim Lokalen kathodischen Korrosionsschutz. Damit wird verdeutlicht, daß auf externe Meßproben nicht verzichtet werden kann.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19830340503
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  • 3
    Electronic Resource
    Electronic Resource
    Time-resolved spectroscopy of stretched polypropylene films (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 20 (1982), S. 445-452 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.130200808
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  • 4
    Electronic Resource
    Electronic Resource
    Unique hydrophobic interactions of pyrene in aqueous solution as effected by polyelectrolytes and surfactantsPresented at the Tenth Northeast Regional Meeting of the American Chemical Society, Clarkson College, Potsdam, New York, June 30-July 3, 1980. (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2473-2490 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrene substituents covalently bounded to polyelectrolytes show not only excited-state interactions but also unique ground-state interactions in aqueous solution. The pyrene moieties in pyrenesubstituted ionic molecules also show these interactions when aqueous solutions of these molecules are treated with polyelectrolytes or surfactants well below their critical micelle concentrations. These hydrophobic interactions are revealed by changes in absorption, fluorescence, and excitation spectra. The well-resolved vibrational bands in the absorption and excitation spectra of pyrene become somewhat diffuse, whereas monomer fluorescence is reduced and replaced by excimer fluorescence. The rationale for these results is that the pyrene moieties in these ionic solutions seek out hydrophobic locations on the polyelectrolytes or surfactants, where pyrene aggregation is responsible for these interactions and the corresponding changes in spectra.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.170210829
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  • 5
    Electronic Resource
    Electronic Resource
    Probes of the microenvironments of the cationic copolymers of styrene and vinylbenzenetrialkylammonium halides (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2395-2412 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The microenvironments of the cationic copolymers of styrene and vinylbenzenetrialkylammonium halides were explored by use of fluorescence spectroscopy. 5-Dimethylamino-1-naphthalenesulfonate (DANS) and 1-pyrenebutyrate (PB) were the fluorescent probes selected to bind to the polymers. The fluorescence energy of the former responds to the polarity or hydrophobicity of the microenvironment, whereas the absorption and fluorescence of the latter reveal the extent of ground-state and excited-state interactions. Polyelectrolyte coiling occurs in proportion to the fraction of binding sites occupied with charge-neutralizing, probe molecules. The bound DANS probe shows that coiling makes the binding-site environment more hydrophobic, and the bound PB probe shows that coiling facilitates excimer formation not only with nearest-neighbor pyrene moieties, but also with non-nearest neighbors. With methyl groups at the quaternary nitrogen binding sites, pyrene moiety interactions preceding excimer fluorescence occur in both ground and excited states. When the methyl groups are replaced with butyl or pentyl groups, pyrene excimers still form in the excited state, but the weak, hydrophobic interactions of the pyrene ground state decrease, because the longer alkyl groups serve as hosts for the hydrophobic pyrene moieties.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221010
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  • 6
    Electronic Resource
    Electronic Resource
    Assessment of toxic hazards of smoke: Toxicological potency and intoxication rate thresholds (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 7 (1983), S. 128-131 
    Details
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Smoke toxicity test methods which determine only lethal toxicological potency under ‘worst case’ conditions do not satisfactorily address the critical issue of relative hazard, including time-to-escape and tenability limits resulting from the fire performance of materials under comparable conditions. Since threats to escape from a fire are largely time-dependent, toxic insults produced by burning materials should also be considered as rate processes. Assessment of time thresholds exhibited by burning materials under test conditions to effect performance impairment (incapacitation) of an animal model would appear to be more relevant than lethal toxicological potencies in estimating probability of successful escape from fires. A model is advanced in which intoxication rate thresholds for materials are obtained using a rodent exposure test method. Concentration-time curves, obtained from experimentally derived concentration-time-response surfaces, are the basis for estimating rate thresholds which are distinctively different for each material and which vary as a function of test conditions. it is this performance impairment response surface which is potentially a key to the modeling of toxic hazards of smoke in perspective with other hazards presented by fire.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fam.810070306
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of addition of high-density polyethylene on the crystallization and mechanical properties of polypropylene and glass-fiber-reinforced polypropylene (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 4669-4686 
    Details
    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: High-density polyethylene up to about 30% by weight was melt-mixed with polypropylene and short-glass-fiber-reinforced polypropylene. The presence of high-density polyethylene and glass fibers in the polypropylene matrix affects its crystallization characteristics, which were studied with the help of differential scanning calorimetry. The blend and composite samples have a large number of polypropylene domains apparently due to an abundance of surface nuclei; as a result, the tensile strength, tensile modulus, and toughness are enhanced. The temperature dependence of shear modulus and logarithmic decrement indicate that high-density polyethylene can have plasticizing effect below the glass transition temperature of polypropylene. The scanning electron micrographs of fractured ends show the presence of dispersed domains in the composite samples.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070271214
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  • 8
    Electronic Resource
    Electronic Resource
    Die Anwendung von Titangußteilen im MRCA Triebwerk RB 199 zur Herstellung eines komplexen Zwischengehäuses (1975)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 6 (1975), S. 361-367 
    Details
    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: The Use of Titanium Castings to Produce a Complex Shaped Intermediate Casing of RB 199.This paper describes the present position on a highly stressed casing and its functions in the RB 199-34 R engine. When the parts of the casing are made from solid forged titanium billets, up to 93% of the material used is machined away. For this reason, the most complicated parts of the casing were procured as castings and welded together by TIG welding. The paper describes the present quality standard of the titanium castings. The tests on the materials and their mechanical properties show that the castings are inferior to the forgings only with respect to their HCF behaviour and their elongation at rupture. Macroscopic flaws are not entirely inevitable but can be detected by X-ray tests. The future prospects for titanium castings are considered favourable.
    Notes: Der Bericht beschreibt die Lage eines hochbeanspruchten Gehäuses und dessen Funktionen im Triebwerk RB 199-34 R. Bei der Herstellung der Einzelteile des Gehäuses aus massiv geschmiedeten Titanblöcken wird bis zu 93% des eingesetzten Materials zerspant. Die kompliziertesten Partien des Gehäuses wurden deshalb als Gußteil bezogen und mittels WIG-Schweißung verbunden. Der Bericht beschreibt den heutigen Qualitätsstand der Titangußteile. Die Ergebnisse der Werkstoff- und Festigkeitsuntersuchungen weisen nur im HCF-Verhalten und der Bruchdehnung Nachteile des Gusses gegenüber dem geschmiedeten Material aus. Makroskopische Fehler sind nicht vollständing vermeidbar, aber durch Röntgenprüfung nachzuweisen. Die künftigen Aussichten des Titangusses werden positiv beurteilt.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19750061102
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  • 9
    Electronic Resource
    Electronic Resource
    Thermodynamic parameters of the helix-coil transition in polypeptide chains. III. Random copolymers of L-leucine with L-glutamic acidThe preceding two papers of this series are Refs. 1 and 2. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1739-1753 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conformational transitions induced by pH changes in random copolymers of leucine and glutamic acid have been studied. Significant differences were observed in the potentiometric titration curves of copolymers with small (up to 4%) and large leucine contents. The helical stability of copolymers with small leucine content, determined from titration curves by the Zimm and Rice method, decreases slightly with an increase in the leucine content, whereas the helical stability of copolymers with large leucine content increases sharply with an increase of the leucine content. It is shown that copolymers with large leucine content aggregate in the region of transition into the helical state, but the increase of their helical state stability is not connected with intermolecular aggregation, as it was also observed for a nonaggregating fraction isolated from one of the copolymers by gel chromatography. A conclusion is made that the helix-coil equilibrium constant s for leucine does not itself exceed the s constant for uncharged polyglutamic acid. The stabilization of the helical state in copolymers with large leucine content is due to intramolecular aggregation of helices in these copolymers. The analysis of the leucine residue distribution between helical and nonhelical regions in globular proteins also gives no real arguments to ascribe special helix-forming properties to leucine.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140814
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Korrosionsresistenz von einigen gebräuchlichen Aluminiumwerkstoffen in MeerwasserVortrag vor dem Fachausschuß für „Korrosions- und Bewuchsforschung“ der Schiffbautechnischen Gesellschaft e. V., Hamburg, Oktober 1978. (1979)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 30 (1979), S. 673-684 
    Details
    ISSN: 0947-5117
    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: Determination of Corrosion Resistance of Typical Aluminium Materials in Sea-WaterThe aluminium alloys Al99,5; AlMn 1 Mg 0,5, AlMg 2 Mn 0,8; AlMg3; AlMg 4,5 Mg 1 were subjected to polarization measurements as well as immersion tests on unpolarized samples in artificial sea water. The Free Corrosion Potential and the surface attack were measured.The determined values for the pitting potential of Al99,5 as well as the investigated alloys AlMg and AlMgMn, were found to be nearly independent of the composition. Differences between the alloys were found in immersion test by measurement of the Free Corrosion Potential. These differences can also be seen in the change of potential and surface conditions. The different investigations permit a general concept of the partial corrosion reactions.The results indicate that in aerated artificial sea water the investigated aluminium materials are generally cathodically controlled.
    Notes: An den Aluminiumwerkstoffen Al99,5: AlMn 1 Mg 0,5: AlMg 2 Mn 0,8; AlMg 3; AlMg 4,5 Mn und AlZn 4,5 Mg 1 wurden in künstlichem Meerwasser sowohl potentiostatische Polarisationsmessungen als auch Dauertauchversuche an unpolarisierten Proben unter Registrierung des Freien Korrosionspotentials durchgeführt und die Oberflächenveränderungen mikroskopisch ausgemessen.Die ermittelten Werte für das Lochfraßpotential von Al99,5 sowie von den untersuchten AlMg- und AlMgMn-Legierungen waren unter den genannten Bedingungen nahezu legierungsunabhängig. Bei den Dauertauchversuchen mit Messung des Freien Korrosionspotentials wurden graduelle Unterschiede im Korrosionsverhalten festgestellt, die in der Verlagerung der Potentiale und im Oberflächenbefund erkennbar waren. Die verschiedenen Untersuchungen lassen im Zusammenhang Rückschlüsse über den Ablauf der einzelnen Teilreaktionen der Korrosion zu. Ihre Ergebnisse deuten darauf hin, daß bei den untersuchten Aluminiumwerkstoffen die Korrosionsreaktionen in lufthaltigem bzw. belüftetem künstlichem Meerwasser von 22°C überwiegend kathodisch gesteuert werden.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19790301002
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