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  • Polymer and Materials Science  (43)
  • AERODYNAMICS  (1)
  • 1950-1954  (44)
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 7 (1951), S. 62-69 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The ultraviolet absorption spectra of fractionated cellulose acetate of varying degrees of polymerisation were measured. In the region between 3000 and 3700 Ä the absorption coefficients were found nearly linear to the wave-length of the light absorbed.The change of the absorption coefficient with increasing wave-length is nearly the same for different degrees of polymerisation.
    Notes: Es wurde das UV-Absorptionsspektrum gereinigter Celluloseacetatfraktionen verschiedenen Polymerisationsgrades bestimmt. Im Bereich von 3000 bis etwa 3700 ÄE nimmt der Absorptionskoeffizient ungefähr linear mit der Wellenlänge des eingestrahlten Lichtes ab.Die Änderung des Absorptionskoeffizienten ist bei Fraktionen verschiedenen Polymerisationsgrades für gleiche Änderungen der Wellenlänge etwa gleich groß.
    Additional Material: 3 Ill.
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  • 2
    Publication Date: 2019-06-28
    Description: The effects of primary and. runback icing and frost formations on the drag of an 8-foot-chord NACA 651-212 airfoil section were investigated over a range of angles of attack from 20 to 80 and airspeeds up to 260 miles per hour for icing conditions with liquid-water contents ranging from 0.25 to 1.4 grams per cubic meter and datum air temperatures of -30 to 30 F. The results showed that glaze-ice formations, either primary or runback, on the upper surface near the leading edge of the airfoil caused large and rapid increases in drag, especially at datum air temperatures approaching 32 F and in the presence of high rates of water catch. Ice formations at lower temperatures (rime ice) did not appreciably increase the drag coefficient over the initial (standard roughness) drag coefficient. Cyclic de-icing of the primary Ice formations on the airfoil leading-edge section permitted the drag coefficient to return almost to the bare airfoil drag value. Runback icing on the lower surface did not present a serious drag problem except when heavy spanwise ridges of runback ice occurred aft of the heatable area. Frost formations caused rapid and large increases in drag with incipient stalling of the airfoil.
    Keywords: AERODYNAMICS
    Type: NACA-TN-2962
    Format: application/pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 2 (1951), S. 212-221 
    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: Wetting of metals by waterIn the following own experiments and such of other authors are discussed concerning the balances of wetting of air, water and metal,  -  the explanation of which has hardly been tried so far  - , as they appear to be of importance for the basic research of the corrosion of metals. In view of the fact that their methodic has haidty been used in corrosion research, only the basic trials are demonstrated.Prior to the careful measurings of Bartell and Cardwell only more informative researches on the wetting of metals by water were made by older authors. This article, therefore, starts from the experiments on gold and silver made by Bartell and Cardwell. Own observations on mercury follow, which admit certain qualitative statements on account of the knowledge of the respective surface tension of liquid mercury. As regards other metals, among which platinum shows particularly remarkable results, only preliminary qualitative results can be discussed. They lead to some consequences concerning the question of the sort of combining power of oxygen of air to the surfaces of metals.A survey is given on the indirectly gained values of the surface tension of solid metals. These values yield together with the heats of adsorption obtained on metal catalysers a comparative measure for the different adsorption power on metal surfaces.The conclusions from the observed rivalry between the wetting by water and the adsorption of air are compared with the results of various authors on the adsorption of gases or aequous mediums on metal surfaces. Finally a hypothesis is proposed for the traceadhesion of water (Wasscr-Haftspur-Erscheinung).
    Notes: Im folgenden werden fremde und eigene Untersuchungen über Benetzungsgleichgewichte des Stofftrios: Luft, Wasser, Metall, deren Ausdeutung bisher kaum versucht wurde, zusammenfassend diskutiert, da sie für die Grundlagenforschung der Metallkorrosion von Bedeutung sein dürften. Mit Rücksicht darauf, daß ihre Methodik in der Korrosionsforschung bisher kaum Anwendung fand, werden zunächst die Verfahrens-Grund-Lagen dargelegt.Vor den sorgfältigen Messungen von Bartell und Cardwell wurden nur seitens älterer Autoren mehr orientierende Untersuchungen über die Benetzung von Metallen durch Wasser veröffentlicht. Deshalb wird von den Untersuchungen Bartells und Cardwells an Gold und Silber ausgegangen. Hieran schließen sich eigene Beobachtungen an Quecksilber, welche dank der Kenntnis der in Frage kommenden Grenzflächentensionen des flüssigen Quecksilbers gleichfalls noch gewisse quantitative Aussagen ermöglichen. Uber andere Metalle, von denen Platin besonders bemerkenswerte Erscheinungen lieferte, können nur vorläufige, qualitative Ergebnisse besprochen werden; auch ergeben sich einige Folgerungen zur Frage der Bindungsart von Luftsauerstoff an Metalloberflächen.Nach einem Überblick über indirekt erschlossene Werte der Oberflächentension fester Metalle, die neben den an Metallkatalysatoren erschlossenen Adsorptionswärmen ein Vergleichsmaß für die unterschiedliche „Adsorptionskraft“ von Metalloberflächen ergibt, werden dic Schlußfolgerungen aus der zu beobachtenden Konkurrenz von Wasserbenetzung und Luftadsorption mit Ergebnissen verschiedener Autoren über Adsorption an Metallflächen aus gasförmigem oder wäßrigem Medium verglichen. Schließlich wird für die vom Verfasser früher beschriebene Wasserhaftspurerscheinung eine Hypothese vorgeschlagen.
    Additional Material: 2 Ill.
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  • 4
    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: Quartz Bricks and BlocksAt first only hollow-ware (tubes, vessels, etc.) suitable for the needs of the chemical and allied industries, was manufactured from quartz produced by fusing pure quartz sand. The production of solid articles was neglected, since the advantages of the non-porous structure, combined with its heat and chemical resistant properties, which protect quartzware from the action of pulverised, liquid and gaseous agents, was only realised later. It was the initiative of users which led to the production of quartz bricks, which were used in copper works, Siemens-Martin furnaces chemical works and certain specialised electric furnaces. These quartz bricks proved to be far superior to all other materials, but were found to be too small and too expensive. A well-known glassworks was successful in developing quartz bricks suitable for tank-linings, whereby a far superior quality of glass was obtained with less contamination, better colours and no bubbles, knots or streaks. The same type of brick was also found ot be of great use in chemical works. Quartz bricks and blocks were first produced by means of compressed resistance fusion and, later, by solid fusion, but in every case one fusion operation was required to produce one brick or block. Nowadays blocks are produced by cutting up billets of large cross-sectional area, so that they can be produced in large quantities at economic prices for all purposes where their application has proved successful.
    Notes: Quarzgut, erschmolzen aus reinem Quarzsand, wurde entsprechend den chemischen und ähnlichen Bedürfnissen vorwiegend als Hohlkörper (Rohre, Gefäße, u. ä.) hergestellt,  -  Vollkörper wurden vernachlässigt,  -  die Vorteile der nichtporösen Struktur wurden erst spät erkannt, die verbunden mit der thermischen und chemischen Festigkeit Quarzgut vor dem Angriff staubförmiger, flüssiger und gasförmiger Agenzien schützt. Erst Verbraucher-Initiative führte zum Quarzgut-Stein, der sich in Kupfer-Raffinier-, in Siemens-Martin-, in Spezial-Elektro-Öfen wie in chemische Analgen eingesetzt, allen anderen Stoffen überlegen erwies, aber zu klein und zu teuer war. Eine bekannte Glashütte entwickelte mit Erfolg den Quarzgut-Wannenstein und erzielte damit weit bessere Gläser,  -  weniger Verunreinigungen, bessere Farben, keine Blasen, Knoten, Schlieren! Der gleiche Stein bewährte sich dann auch für Chemische Großanlagen.  -  Quarzgut-Steine entstanden zunächst aus gepreßten Ein- oder Mehrstab-Widerstandsschmelzen, später aus Vollkörper-Schmelzen, doch ergab eine Schmelze nur einen Block. Heute können Blöcke von einem querschnitts-großen Strang abgetrennt und zerteilt werden,  -  so ist Massen-Herstellung zu billigen Preisen für alle erprobten Zwecke möglich.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 1 (1950), S. 481-487 
    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
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 5 (1954), S. 425-430 
    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: Reactions in the Intermediate Stratum between Iron and Coating Systems and the Effect of InhibitorsCorrect surface pre-treatment of iron and steel is regarded as irremissible for good performance and maximum service life of a coating system in corrosion control. The peculiar features of surface texture are characterized by a mosaic of anodic and cathodic ranges. Industry's tendency to speed up every process to the utmost calls for quick drying paints. Their wetting properties and their water permeability determine adhesion characteristics and electrochemical attack. Therefore, the paint chosen has to correspond with the pre-treatement applied to the surface or vice versa. The addition of suitable inhibitors contributes to the efficiency and performance of the coating. Combinations of inhibitors with ionadsorbing film-forming materials create an active intermediate stratum between metal and paint, improving adhesion and preventing corrosion. The development of a special surface-technology is necessary for pursuing the aim of prolonging the life of steel structures and/ or reducing maintenance costs, even under the most severe service conditions.
    Notes: Eine fachgemäße Vorbehandlung der Oberfläche von Eisen und Stahl, die als Mosaik anodischer und kathodischer Bereiche aufgefaßt werden kann, ist für dauerhafte Rostschutzanstriche eine unerlässliche Vorbedingung. Das moderne Fertigungstempo zwingt die Industrie zur Verwendung rasch trocknender Anstriche; deren Benetzungsvermögen bedingt die Haftung und deren Wasserdurchlässigkeit die elektrochemischen Vorgänge in der Grenzschicht. Die Anstriche müssen also der Vorbehandlung des Eisens entsprechen, oder diese Vorbehandlung hat sich nach den gewählten Anstrichmitteln zu richten. Zusatz geeigneter Hemmstoffe verbessert die Rostschutzwirkung erheblich. Kombinationen von Hemmstoffen mit ionenabsorbierenden Filmbildern führen zu aktiven Zwischenschichten, die zur Erhöhung der Haftfestigkeit und zur Verhütung von Unterrostungen beitragen. Schließlich wird eine Oberflächen-Technologie postuliert, die sich die Verlängerung der Lebensdauer von Stahlkonstruktionen und/oder eine Verminderung ihrer Unterhaltskosten, auch unter schwierigsten äußeren Bedingungen, zum Ziel setzt.
    Additional Material: 7 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 6 (1951), S. 667-668 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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  • 8
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The elastoviscous behavior of polyisobutylene may be interpreted in terms of a mechanical model consisting of a distribution of Maxwell elements connected in parallel. The structure of this “generalized Maxwell model” is specified by the distribution of relaxation times of the component elements. The relaxation of stress curve of the material is directly related to the distribution of relaxation times, and general expressions for the bulk viscosities (tensile and shear) of such a system in terms of the distribution of relaxation times are readily obtained.A simple “box distribution” of relaxation times is described which can be used to approximate the relaxation behavior of polyisobutylene at the long-time end of the relaxation time spectrum, and in terms of which the expressions for bulk viscosity reduce to very simple form. The parameters specifying this distribution may be determined from experimental relaxation curves by a simple graphical method. Values of these parameters as a functions of molecular weight and temperature are computed, by use of these data. It is shown that bulk viscosity values calculated from relaxation data by this method are in good agreement with experimental values for both tensile and shear deformations, and for both unfractionated and fractionated polymers. Measurements of viscosity and of relaxation of stress can thus be directly correlated, and could be used in combination to characterize elastoviscous properties over wide ranges of molecular weight and temperature.
    Additional Material: 9 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 579-581 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 10 (1953), S. 510-512 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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