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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 533-546 
    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: A miniature dart drop test was used in a study of the mechanism of reinforcement in impact resistant rubber-modified polystyrene. A typical SBR-polystyrene system was diluted with varying amounts of polystyrene, and thin compression moldings were made from each blend. The impact-whitened areas were observed directly under the microscope and photomicrographs are presented. The whitening is caused by scattering of light from interfacial separation of portions of many rubber particles from polystyrene and by formation of a multitude of microcracks and/or crazes, starting at the partially separated particles. The absorption of energy by this mechanism can be very large. The driving force for the initial separation appears to be the triaxial tension under which the rubber particles exist, and this results from the higher volume shrinkage rate of rubber compared to that of polystyrene. Included also are photomicrographs taken of specimens after tensile stretching, and the mechanism derived from the impact case is extended to explain the increased elongation and corresponding whitening.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 45 (1994), S. 58-64 
    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: Microbial deterioration of materials - biofilm and biofouling: Investigation into biofilms by FTIR spectroscopyThe investigation of the development and properties of biofilms is difficult because classical microbiology offers only destructive methods apart from microscopical observation. This paper presents the FTIR spectroscopy as a means to investigate microorganisms in biofilms. Furthermore, in completion to taxonomical and genetical methods for the identification of microorganisms, the FTIR analysis provides fingerprint spectra, allowing the rapid characterization of microbial strains. The FTIR-ATR technique can be used for the observation of biofilms forming directly on the ATR crystal. Spectra can be gained non-destructively, in situ and in real time. The method is suitable for fundamental biofilm research as well as for monitoring of biofilm formation, e.g., in an ultrapure water system. It also allows the rapid analysis of deposits on filtration membranes or other surfaces and supports the discrimination between microorganisms, inorganic material or other foulants. The potential of the diffuse reflexion (DRIFT) is emphasized. With the DRIFT method it is possible to investigate rough surfaces or pulverized material and to detect biomass or other surface contaminants. The examples demonstrate that the FTIR spectroscopy holds a powerful potential for biofilm analysis and can be applied in manyfold ways.
    Notes: Um Fragestellungen der Entwicklung und Eigenschaften von Biofilmen zu bearbeiten, gibt es in der klassischen Mikrobiologie außer der mikroskopischen Betrachtung keine zerstörungsfreien Methoden. In dieser Arbeit werden einige Varianten der FTIR-Spektroskopie als Möglichkeit zur Untersuchung von Mikroorganismen und Biofilmen vorgestellt. In Ergänzung zu taxonomischen und gentechnischen Verfahren zur Identifikation von Mikroorganismen kann auch ausgenutzt werden, daß die FTIR-Spektren von Reinkulturen hinreichend charakteristisch sind, um eine rasche Zuordnung zu ermöglichen. Auf dieser Basis wird derzeit eine Spektrenbibliothek für Umweltbakterien aufgebaut. Die FTIR-ATR Technik erlaubt speziell die Beobachtung von Biofilmen, die sich auf dem ATR-Kristall bilden. Spektren können zerstörungsfrei, in situ und in Echtzeit gewonnen werden. Die Methode eignet sich für Grundlagen-Untersuchungen und zum Monitoring der Biofilm-Bildung, z. B. in hochreinen Wassersystemen. Mit ihr können auch Beläge - z. B. auf Filtrationsmembranen oder anderen Oberflächen - hinsichtlich ihrer Zusammensetzung innerhalb kurzer Zeit analysiert werden. Damit kann zwischen der Belagsbildung durch Mikroorganismen, anorganischen Kristallen o.a. unterschieden werden. Es wird auch noch auf die Anwendungsmöglichkeit der diffusen Reflexion (DRIFT) hingewiesen, mit der es gelingt, organische Beläge auf rauhen, anorganischen Oberflächen zu erkennen. Die Anwendungsbeispiele zeigen, daß die FTIR-Spektroskopie ein großes Potential für die Biofilm-Analytik enthält und in vielfältiger Weise eingesetzt werden kann.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 3 (1960), S. 132-142 
    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: A short-time stress-relaxation apparatus similar to that of Watson, Kennedy, and Armstrong was built. A large compressed spring is used to attain high strain rates which m.ere kept constant at 3GO in./min. by controlling the spring motion hydraulically. Measurements wcre made at room temperature on injection-molded bars of polystyrene, styrene. ticrylonitrile copolymer, and a rubber-styrene polymer. No correlation could be seen between the short-time stress-relaxation rates and impact resistance or “toughness.” The apparatus, however, has proved to be very useful, because it furnishes a means of straining a specimen rapidly and recording the stress and its decay with time. Stress-strain curves for a high straining rate have been constructed from the data. A high-speed flexural test can be made by modifying the specimen holders. This flexural test has shown a correlation between the dart-drop impact strength of an object and the deflection a t breakage of specimens cut perpendicular to the flow of plastic in the mold. In addition, it was found that stress relaxation data can be used to measure critical elongation (or critical stress) as a function of time, without observing the formation of craze cracks. A mechanism of reinforcement of polystyrene by rubber particles is proposed. A phase-contrast photomicrograph is presented as evidence that the energy of nondestructive impact is used up in forming many short cracks radiating out around the rubber particles. A general whitening in the specimen results which is caused by reflection and scattering of light from the many planes.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 2681-2691 
    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: The retraction of injection-molded polypropylene at temperatures close to its melting point has been studied. At a given temperature above 150°C., retraction reaches a limit within a few minutes. Upon increasing the temperature, this equilibrium retraction changes to a higher characteristic value. The previous heating history strongly affects the equilibrium retraction. In fact, specimens can be prepared which exhibit negligible retraction up to the melting point where complete shrinkage occurs. Equilibrium retraction at a given temperature is ascribed to a melting of crystallites smaller than the specific size associated with that temperature. The remaining larger crystallites prevent further shrinkage.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 18 (1984), S. 797-807 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Implantable biomedical sensors built on a silicon substrate capped with glass are currently being developed for intravascular applications. Electrical techniques for inhibiting thrombus formation on the surface of a proposed optical sensor in direct contact with blood have been investigated. Glass-on-silicon specimens (4 × 1.2 × 0.4 mm3) were coated with indium-tin oxide, a transparent conductor, and implanted in the vena cava and iliac veins of three dogs for 10, 20, or 33 days. The equilibrium surface - blood interface potentials of the specimens were modified by implanted current sources which supplied either direct current (8-15 m̈A) or 100 KHz alternating current (5 m̈A, root mean square). Light-microscopic and scanning electron-microscopic analyses showed each of the DC-polarized specimens to be free of thrombus, in contrast to nonpolarized (control) specimens on which varying amounts of adsorbed protein and thrombus deposits were found. Like the control specimens, the AC-polarized specimens formed thrombus, but the appearance of the deposits differed. These findings support the view that the polarity, magnitude and time dependence of the potential across conducting surface - blood interface significantly influence thrombogenicity. Further work is necessary to determine the roles of electrochemical and electrostatic factors in preventing thrombus formation on foreign materials.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 18 (1992), S. 789-793 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Polycrystalline Ni-20 Cr alloy ribbons were studied after low-pressure oxidation (3.3 × 10-4 Pa) at 750° C by scanning Auger microanalysis with argon ion sputter profiling. Only chromium oxide is formed under our experimental conditions and a 10% mechanical predeformation (uniaxial deformation) at ambient temperature is found to promote strongly the oxide formation on the alloy surface. In effect, it notably reduces the incubation period that precedes all our oxidations. However, the presented analysis reveals that the chromium oxide distribution is very heterogenous on predeformed oxidized samples at the beginning of the reaction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 27 (1958), S. 587-589 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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