ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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 dynamic-mechanical properties as a function of temperature and the low- and high-speed tensile properties at 23°C have been determined on specimens of conventional suspension-polymerized PVC and of low-temperature-polymerized PVC roll milled and then compression molded at different temperatures. It has been found that the main transition α and the shear modulus above Tα depend on the thermal history and are strongly affected by crystallinity, whereas the dynamic-mechanical spectrum below Tα is not influenced by these parameters. Room-temperature tensile modulus and yield properties are very little affected by processing history and crystallinity. The elongation at break and the fracture energy, on the contrary, increase, at any fixed strain rate, for conventional PVC with milling temperature. The same trend has been found for low-temperature PVC, but the elongation at break-versus-temperature curve is shifted, as a whole, toward higher temperatures by approximately 50°C. Such results are discussed in terms of homogeneity of the specimens, which is controlled by the melting process of the crystallites. Stereoscanning electron micrographs of fracture surfaces appear to substantiate these conclusions.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 2487-2512 
    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 dynamic-mechanical properties as a function of temperature and frequency were measured for five samples of polycaprolactam (nylon 6) containing different amounts of hydrosoluble products. Low- and high-speed tensile properties and Izod impact strength were determined between -190° and 100°C for the same samples by using autographic methods. The influence of the mechanical relaxation processes on moduli, yield strength σy, yield strain εy, tough-brittle transition temperature, elongation at break εR, and tensile and Izod fracture energies was investigated. It has been found that some mechanical properties, such as modulus and yield properties, can be directly related to specific relaxation phenomena, whereas as far as other properties, such as the ultimate properties, are concerned, the existing correlation can be concealed by the interference of purely mechanical phenomena which depend on the testing technique used, the testing conditions, and the previous history of the material.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2011-02-15
    Description: SUMMARYA reliable evaluation of crop nutritional status is crucial for supporting fertilization aiming at maximizing qualitative and quantitative aspects of production and reducing the environmental impact of cropping systems. Most of the available simulation models evaluate crop nutritional status according to the nitrogen (N) dilution law, which derives critical N concentration as a function of above-ground biomass. An alternative approach, developed during a project carried out with students of the Cropping Systems Masters course at the University of Milan, was tested and compared with existing models (N dilution law and approaches implemented in EPIC and DAISY models). The new model (MAZINGA) reproduces the effect of leaf self-shading in lowering plant N concentration (PNC) through an inverse of the fraction of radiation intercepted by the canopy. The models were tested using data collected in four rice (Oryza sativaL.) experiments carried out in Northern Italy under potential and N-limited conditions. MAZINGA was the most accurate in identifying the critical N concentration, and therefore in discriminating PNC of plants growing under N-limited and non-limited conditions, respectively. In addition, the present work proved the effectiveness of crop models when used as tools for supporting education.
    Print ISSN: 0021-8596
    Electronic ISSN: 1469-5146
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...