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  • 1995-1999  (1)
  • 1985-1989  (3)
  • 1945-1949
  • Chemical Engineering  (3)
  • Aerosol  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nuclear medicine 22 (1995), S. 473-476 
    ISSN: 1619-7089
    Keywords: Technegas ; Pertechnegas ; Lung ; Particle size ; Aerosol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Technegas and Pertechnegas are radioactive aerosols produced in a commercial generator and used for lung scintigraphy. The aerosols are produced by first evaporating to dryness standard technetium-99m generator eluate (99m-TcO4 in normal saline) in a graphite crucible (thesimmer stage) and then heating this to 2500° C (the „burn” stage). The aim of this work was to measure the particle size distributions of these agents and relate this to regional lung deposition. Factors that may vary during production of the aerosol in routine use were investigated to determine whether they influenced the particle size. Activity size distributions were measured using a serial wire-screen diffusion battery. The Technegas size distribution was approximately log-normal with an activity median diameter of 158 nm and a geometric standard deviation of 1.5. The results for Pertechnegas were similar. The median size increased with the number of simmers and with the time from generation. The increase in size with the number of simmers is thought to be due to the increased salt content in the crucible prior to the „burn”. The predicted lung deposition is 37% in the alveolar region and 5% in the bronchial region. Significant changes in deposition are not predicted over the range of particle sizes measured.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 1165-1168 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 method is presented to study the mechanical behavior of soft, UV curable coating material as a function of temperature of the prepolymer at cure. For such materials, the crosslink density (hence, equilibrium modulus) is found to decrease with increasing cure temperature. The three primary coatings are: a polyurethane acrylate with a nominal equilibrium tensile modulus of 200 psi, a polyurethane acrylate with a nominal equilibrium modulus of 1200 psi, and a non-urethane acrylate with a nominal equilibrium tensile modulus of 60 psi.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 1169-1171 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 strength of the bond between primary coating and glass for a dual coated lightguide may be judged by fixing the coating to a substrate and pulling the glass out. The values obtained from such measurements are shown to exhibit a temperature and rate dependence similar to the mechanical properties of the primary coating for a given coating system. Here we combined temperature and rate data for a universal description of the coating to glass adhesion for a dual coating system.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 25 (1985), S. 105-112 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 frequency dependence of the complex-shear modulus of a nonbrominated flame-retardant polycarbonate has been successfully represented from 1 hertz (hz) to 1 gigahertz (ghz) at 190°C using a mechanical analog of the Cole-Cole dielectric analysis. Two sets of retardation times were required centered about 74 msec and 16 μsec. The β value for the short time response was 0.83 and for the longer time response was 0.58. The values of JoN determined from the common point at which the terminal-zone arc and the transition-zone arc touch the Jc″ = 0 axis yields an entanglement molecular weight, Me, of 1470 g/mole.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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