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  • 1
    Electronic Resource
    Electronic Resource
    Formation and vertical distribution of sapwood and heartwood in Cryptomeria japonica D. Don (1994)
    Springer
    Trees 9 (1994), S. 35-40 
    Details
    ISSN: 1432-2285
    Keywords: Cryptomeria japonica ; Heartwood ; Sapwood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The formation and vertical distribution of sapwood and heartwood were studied with a 45-year-old Cryptomeria japonica D. Don. The tree was grown at a plantation with 1.5 m × 3.0 m spacing near Miao-Li, Taiwan and was felled on 27 February 1992. The thickness of sapwood and heartwood was expressed by a ring count and a linear measurement. The east-west (E-W) wood strips were collected from 0.3 m above ground upwards to the top of the tree at 2.5 m intervals. The sapwood thicknesses from the base to the 10.3 m tree level height are around 20–22 growth rings and 42±2 mm. At the top of the tree, the sapwood thickness is narrower. The heartwood, which decreases in thickness with increasing tree level heights is not found at the top of the tree. The heartwood appears as a conical shape in the tree trunk. There is no statistical difference in sapwood/heartwood thickness between E-W aspects. Tree level heights and the tree level age were found to be important parameters in determining the thickness of sapwood/heartwood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197867
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Oxidation characteristics of Ti-4.37 wt.% Ta alloy in the temperature range 1258–1473 K (1980)
    Springer
    Oxidation of metals 14 (1980), S. 167-185 
    Details
    ISSN: 1573-4889
    Keywords: air and oxygen oxidation ; pressure influence ; X-ray identifications ; oxygen diffusion ; oxidation mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Oxidation kinetics of Ti-4.37 wt.% Ta (1.19 at.%) alloy in either air or oxygen have been investigated in the temperature range 1258–1473 K and at three pressure levels: 0.013, 0.133, and 1.0 bar. X-ray data reveal only TiO2 (rutile) as the main oxide and, in addition, TiO2, S-TiN, and ɛ-TiN at the metal surface for oxidation in air at 1273 K. The ɛ-TiN phase was not detected at higher temperatures. Electron microprobe analyses are used to determine the concentration profiles of Ti, Ta, O, and N across the oxide scale and in the metal. Microhardness traverses follow the oxygen distribution in the alloy. The oxygen diffusion coefficient,D = 60.8 exp(−235.1/RT), as determined from weight-gain measurements, is in reasonable agreement with that calculated from microhardness data. The oxidation mechanisms for oxidation of the alloy in air or oxygen are proposed.The existence of interstitial Ti cations in the oxide is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603992
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    High-temperature oxidation of Ti-4.32 wt.% Nb alloy (1980)
    Springer
    Oxidation of metals 14 (1980), S. 147-165 
    Details
    ISSN: 1573-4889
    Keywords: oxidation in air or oxygen ; kinetics ; oxide identification ; oxygen diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation kinetics of Ti-4.32 wt.% Nb (2.27 at.%) alloy in either air or oxygen under 1 bar pressure have been investigated in the temperature range of 1255–1471 K. For oxidation in oxygen the kinetics follow consecutively decreasing parabolic rate laws. The kinetics become nonparabolic after prolonged oxidation in air. X-ray data reveal the presence of TiO2 (rutile) as the main oxide. The presence of Ti2O, δ-TiN, and ɛ-TiN is found on the metal surface after oxidation in air. Microhardness and electron microprobe measurements are used to determine Ti, Nb, O, and N profiles across the oxidized alloy. The oxygen diffusion coefficient in the alloy can be expressed byD=65.6 exp(−234.3/RT) with the activation energy in kilojoules per mole. The oxidation behavior of the alloy is explained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603991
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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