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  • 1
    Electronic Resource
    Electronic Resource
    Thermal conductivity by a pulse-heating method: Theory and experimental apparatus (1990)
    Springer
    International journal of thermophysics 11 (1990), S. 629-641 
    Details
    ISSN: 1572-9567
    Keywords: dynamic measurements ; high temperature ; scanning pyrometry ; thermal conductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new dynamic technique for the measurement of thermal conductivity at high temperatures has been developed at the IMGC. The specimen is brought to high temperatures with a current pulse; during cooling the heat content is dissipated by radiation and by conduction. The differential equation describing this process contains terms related to the heat capacity, the hemispherical total emittance, and the thermal conductivity of the material. If the first two properties are determined using the same specimen during subsecond pulse heating experiments, thermal conductivity may be evaluated by accurate measurements of the round-shaped temperature profiles established on the specimen during cooling. High-speed scanning pyrometry makes possible accurate measurements of temperatures and of temperature derivatives (with respect to space and time), which enables the differential equation describing the power balance at each point of the specimen to be transformed into a linear equation of the unknown thermal conductivity. A large overdetermined system of linear equations is solved by least-squares techniques to obtain thermal conductivity as a function of temperature. The theory underlying the technique is outlined, the experimental apparatus is described, and details of the measurement technique are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01184333
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal expansion of high-T c superconductors (1991)
    Springer
    International journal of thermophysics 12 (1991), S. 687-695 
    Details
    ISSN: 1572-9567
    Keywords: high-T c ; superconductivity ; thermal expansion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Measurements are reported of the linear thermal expansion of polycrystalline samples of BiCaSrCu oxide and BiPbCaSrCu oxide from 2 K up to about 1000 K. The measurements are compared with our earlier data on LaSrCu oxide and YBaCu oxide materials and are found to be similar in magnitude at normal temperatures. Near the superconducting transition temperature T c, anomalies in the linear coefficient α (T) are small and similar in relative magnitude to those observed in the heat capacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00534224
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Evaluation of thermal conductivity from temperature profiles (1993)
    Springer
    International journal of thermophysics 14 (1993), S. 525-539 
    Details
    ISSN: 1572-9567
    Keywords: dynamic measurements ; high temperature ; scanning pyrometry ; temperature profiles ; thermal conductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new dynamic technique for the measurement of thermal conductivity is being developed at IMGC. The experiment consists in bringing the specimen to high temperatures with a current pulse and in measuring the temperature profiles during the free cooling period. Different techniques can be used to extract the information on thermal conductivity from the profiles. The numerical computation of thermal conductivity from the experimental temperature profiles in absolute space is possible, but it is difficult and cumbersome because one must know and take into the account the exact position of the infinitesimal elements of the specimen in different profiles. Computations in tube-space (a fictitious space where no thermal expansion occurs) are simpler and lead to less complex numerical computations. Complementary techniques to evaluate thermal conductivity as a function of temperature or at constant temperature are presented with a discussion of advantages and disadvantages of each method. Computer simulations have tested the precision of the complex software. Numerically generated temperature profiles from known thermophysical properties have been obtained and thermal conductivity has been recomputed from the profiles. The relative difference using different computational approaches and different fitting functions is always less than 0.1%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566050
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Thermoelastic properties of 350 grade maraging steel (1990)
    Springer
    Journal of materials science 25 (1990), S. 2249-2252 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The elastic moduli of 350 grade maraging steel in the annealed and hardened states have been determined in the temperature range 4.2 to 300 K. Thermal expansion of these steels and pure iron are given for the range 2 to 800 K. The elastic moduli show a normal temperature dependence, increasing with decreasing temperature, and a zero temperature derivative at 0 K. The low-temperature thermal expansion coefficient is the sum of a linear and cubic term, the former having a negative sign for the steels, which is probably due to magnetic effects. The elastic moduli increase by about 10% on hardening, and this increase is correlated with the structural changes caused by the hardening process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045797
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    Paper (German National Licenses)
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