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  • 11
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les cycles d'activité annuels des fourmis-charpentières et des termites souterrains ont été déduits des relevés poursuivis par le service coopératif des entomologistes dans le Connecticut, le Maryland, le New Jersey, la Caroline du Nord et l'Ohio. Les autocorrélations suggèrent une forte structure cyclique des plaintes issues du public, avec une régularité augmentée du sud au nord. L'analyse spectrale révèle que les Etats les plus au nord présentaient des pics de plaintes à des fréquences plus grandes, alors que les Etats plus au sud avaient des fluctuations de fréquences plus courtes, comme on pouvait s'y attendre si les facteurs climatiques réglaient le système. De tels résultats peuvent être de grande valeur pour les expériences conduites dans la nature.
    Notes: Summary Annual activity cycles of carpenter ants and subterranean termites were extracted from data maintained by cooperative extension service entomologists in Connecticut, Maryland, New Jersey, North Carolina and Ohio. Autocorrelations suggested a strong cyclic patterning of public complaints, which increased in regularity from south to north. Spectral analysis revealed that the more northern states had complaint peaks occurring at longer frequencies, while more southern states had shorter frequency fluctuations, as expected if climatological factors drive the system. The existence of data such as these can be of great value in designing field experiments.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 25 (1990), S. 2249-2252 
    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
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 11 (1990), S. 629-641 
    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
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 12 (1991), S. 687-695 
    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
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 14 (1993), S. 525-539 
    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
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 6 (1985), S. 681-693 
    ISSN: 1572-9567
    Keywords: dynamic measurements ; electrical resistivity ; emittance ; heat capacity ; high temperature ; niobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Data for the heat capacity, electrical resistivity, hemispherical total emittance, and normal spectral emittance (at 898 nm) of niobium are reported for the temperature range 1000–2500 K. Measurements were based on a subsecond pulseheating technique. The results are discussed and compared with the literature values. Reported uncertainties for the properties are 3% for heat capacity, 1% for electrical resistivity, 5% for hemispherical total emittance, and 4% for normal spectral emittance.
    Type of Medium: Electronic Resource
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