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  • 1985-1989  (7)
  • 1850-1859
  • Polymer and Materials Science  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Acetylene-norbornene copolymers (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3937-3949 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metathesis ring opening polymerization has been used to copolymerize norbornene and 7,8-bis(trifluoromethyl)tricyclo[4,2,2,02,5]deca-3,7,9-triene. Subsequent thermal elimination of the precursor copolymers yielded acetylene-norbornene copolymers. The undoped copolymers were found to have electrical conductivity, spin concentration, and EPR linewidths which vary with composition. The location of the trans-C—H out-of-plane vibration, however, was invariant at 1010cm-1 indicating that conjugation length of n 〉 4 are present even at 40% acetylene content in the copolymer. The copolymers containing 79 mol % of acetylene units attained a doped conductivity of 0.02 S/cm with a dopant concentration of 6 mol % of I3- per sp2 carbon.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271206
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal degradation of model compounds with blocked hemiacetal group related to (4-O-methyl-D-glucurono)-D-xylan (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 1473-1477 
    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: Reduced (4-O-methyl-D-glucurono)-D-xylan and nine methylglycosides related to this polysacharide were studied by dynamic and isothermal thermogravimetry. It could be stated from the results that the thermal stability of saccharides is increasing with increasing number of pyranose units. The models related to (4-O-methyl-D-glucurono)-D-xylan are more thermally stable than the corresponding hexoglycanic models. Rates of gasification of models containing uronic acid methylesters are higher than those of neutral methylglycosides. The rate of polysaccharide gasification was the highest one from all models studied. The supramolecular structure of polysaccharide is dramatically influencing the course of thermal degradation.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330503
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Dyeing and chemical technology of textile fibers. Von E. R. Trotman. 6. neubearb. Auflage. ISBN 0-85264-267-9. High Wycombe: Charles Griffen 1984. X, 587 s., geb. £ 27.95. (1985)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 36 (1985), S. 456-457 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1985.010360816
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Improved Gurney Formulas for Exploding Cylinders and Spheres using “Hard Core” Approximation (1986)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 11 (1986), S. 81-84 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The final liner velocity predicted by the Gurney formulas for sandwich cylindrical and spherical configurations for very light liners (small M/C values) are (6E)1/2, (4E)1/2 and (10E/3)1/2 respectively. The existance of these differences among the limiting velocity values contradicts the well known fact that the explosive products' escape velocity does not depend on the initial geometry of the explosive when no Mach waves are formed.An improvement to the Gurney formulas for exploding cylinders and spheres is suggested which corrects this basic inconsistancy. It is based on the observation that light liners are accelerated to their final velocity in a short time getting their kinetic energy mainly from that part of the explosive which is in contact with them. It is shown that by excluding from the explosive mass the inner volume and replacing it with an infinitely hard core the experimentally measured liner velocities for the cylindrical and spherical geometrics are more accurately reproduced. The core radius is found by maximizing the liner velocity, thus getting the fastest transformation of the gas potential energy to kinetic energy which is possible within the model assumptions. The improved formulas predict for the limit of very small M/C the same velocity, (6E)1/2 for all the above mentioned geometries. The comparison of the improved formulas with available experimental data reveals how the accuracy of the Gurney model is limited at the large and the small values of M/C.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19860110303
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  • 5
    Electronic Resource
    Electronic Resource
    General Kinematical Solution to the Motion of an Explosively Driven Liner (1986)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 11 (1986), S. 53-64 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown that the motion of an explosively driven smooth thin liner, obeys, whenever the material forces are negligible, the following equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ \partial {\rm V}_l /\partial {\rm t = }\partial {\rm (}\frac{{{\rm V}^{\rm 2} }}{2}{\rm) / }\partial l, $$\end{document} where V is the liner velocity, ∂Vl/∂t is the time derivative of the velocity component along the liner direction and l is the Lagrangian coordinate measuring the length of the liner contour (formation line). The transformation from the rest to moving coordinate system is calculated, as well as a very accurate approximation to the liner elongation. Under the assumption of an exponential acceleration a closed form for the liner elongation is obtained. The influence of the liner curvature on the projection angle δ is also found. The comparison of the obtained solution with two dimensional Lagrangian code calculations shows a very good agreement. Finally, some predictions of the model are discussed for demonstrating its applicability to various problems.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19860110205
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  • 6
    Electronic Resource
    Electronic Resource
    The Mott Fragmentation Model and the Vpl break-up parameter (1989)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 14 (1989), S. 31-38 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown that the Mott fragmentation model and the Hirsch formula for the shaped charge jet break-up time complete one another to yield a unified model. This model is consistant with the microscopic picture of internal flow splitting in the metal, into shear bands undergoing a strain larger than the average and the metal between them which undergoes a strain which is smaller than the average. This splitting reduces the deformation energy dissipated by the metal while elongating. It corresponds to the splitting of the stress versus strain characteristics of the metal into the isothermic and adiabatic curves as measured by Johnson and Cook. The parameter Vplwhich describes the break-up process according to the Hirsch model, is identified with the expression (dσm/ϱ)1/2 where dσm is the difference in yield strength between the isothermic and adiabatic curves where the adiabatic characteristic becomes a maximum. The comparison with available experimental measurements of this prediction shows a very encouraging agreement. The weak dependence of Vpl on the strain rate on the one hand and the observed increase of the jet break-up time in slowly elongating jets on the other hand are also explained using energy considerations. The recent recovery of jet particles by Zernow yields supportive evidence of the proposed theory which may be extended to all semi steady metal plastic flow phenomena. The final break-up, according to this model is due to the separation between the two sides of shear bands where the slide motion went on during the whole deformation process.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19890140108
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  • 7
    Electronic Resource
    Electronic Resource
    Simplified and Extended Gurney Formulas for Imploding Cylinders and Spheres (1986)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 11 (1986), S. 6-9 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The usefulness of the Gurney formulas in application to one-dimensional computer codes for shaped charge design has called for their extention to predict the asymptotic velocities of imploding cylinders. Two different approaches by Chou, Carleone, and Flis on 1981 and by Chanteret on 1983 have led to improvements which were shown to predict correctly two-dimensional code simulations for unconfined charges. Both works did not lead however to simple formulas which retain the conveniency of the original Gurney formulas. In the work presented, closed form analytical solutions for both the cylindrical as well as the spherical geometries are derived. The solution for each geometry is presented in a way in which the symmetry between the inner liner and the confinement is easily recognized. The relation of each solution to the Gurney formula for asymmetrical sandwich is also obvious. The presented solutions reduce to all the known Gurney formulas for the more simple geometries at the appropriate limits. The accuracy of the predictions by the obtained formulas is limited however when the assumptions of the Gurney model do not describe the real physical situation closely. This happens in general in extreme cases, e.g. when the liners are very light comparing to the explosive mass or when the ratio between the confinement radius and the inner liner radius is very large comparing to unity.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19860110103
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