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  • 1985-1989  (3)
  • Behavior  (1)
  • Chemistry  (1)
  • Columbite  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 45 (1989), S. 215-222 
    ISSN: 1420-9071
    Keywords: Behavior ; learning ; leaf surface ; wax ; insects ; food selection ; secondary compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Direct observations on the feeding behavior of insect herbivores are uncommon, but important. The important aspects of host-plant selection by phytophagous insects that have been revealed by such observations are the role of chemicals in the leaf surface, and learning. There are few detailed reports of behavior at the leaf surface, but these indicate that many, if not all, insects exhibit behavior pattenrs that can be interpreted as an examination of the quality of the surface and acceptance or rejection may follow without further testing. A number of experiments show that chemicals from the leaf surface commonly contribute to the acceptability or otherwise of a plant and in most cases so far the active chemicals are of widespread occurrence, not having a specific association with the host plant. Some experiments show that the association between surface chemicals and plant palatability is learned, but in other cases there is evidence of an innate response. Habituation to deterrent chemicals has been demonstrated in the laboratory, but not in the field. Food aversion learning also occurs and may be important in dietary switching by polyphagous insects.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1438-1168
    Keywords: Tantalum ; Niobium ; Titanium ; Columbite ; Rutile ; Mineralogy ; Geochemistry ; Pegmatite ; Austria ; Ostalpen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Titan-Ferrocolumbit ist ein seltenes Akzessorium in den Spodumenpegmatiten der Weinebene, Kärnten, Österreich. Er enthält entmischten niobhaltigen Rutil und selten Einschlüsse von möglicherweise primärem Zinnstein. Die Zusammensetzung des TitanFerrocolumbits ist relativ homogen und weist die folgenden Elementverhältnisse auf. Mn/(Mn + Fe) 0,24 – 0,33, Ta/(Ta + Nb) 0,09 – 0,13 (Atomverhältnisse) und 0,47 – 0,88 Ti pro 12 Kationen (2,7 - 5,0Gew.%TiO2). Natürlich auftretende Kristalle sind strukturell merklich ungeordnet und erlangen durch Erhitzen einen höheren Ordnungsgrad. Die Mn/(Mn + Fe) sowie Ta/(Ta + Nb) Verhältnisse des niobhaltigen Rutil betragen 0,00 – 0,04 bzw. 0,26 – 0,38. Der niobhaitige Rutil ist im Vergleich zu Mn- und Nb-führendem Ferrocolumbit an Fe, Ta, Ti und Sn angereichert.—Die Seltenheit von Nb, Ta-Oxiden in den spodumenführenden Pegmatiten der südlichen Ostalpen steht in Übereinstimmung mit ihrer Zugehörigkeit zum Albit-Spodumen Typ der selten-Element-führenden Pegmatite (rare-element pegmatites).
    Notes: Summary Titanian ferrocolumbite is a rare accessory mineral in the spodumene-bearing pegmatites at Weinebene, Carinthia, Austria. It contains abundant exsolved niobian rutile and scarce inclusions of cassiterite that may be primary. The titanian ferrocolumbite is relatively homogeneous with Mn/(Mn + Fe) 0.24–0.33, Ta/(Ta + Nb) 0.09–0.13 (atomic ratios) and 0.47–0.88 Ti per 12 cations (2.7–5.0 wt.% TiO2). Natural specimens are considerably disordered but become more ordered on heating. Niobian rutile has Mn/(Mn + Fe) 0.00–0.04 and Ta/(Ta + Nb) 0.26–0.38; it concentrates Fe, Ta, Ti and Sn relative to the Mn- and Nb-enriched ferrocolumbite. The overall scarcity of Nb, Ta-oxide minerals in the spodumene-bearing pegmatites of southern Ostalpen conforms to their general features ranking them with the albite-spodumene type of rare-element pegmatites.
    Type of Medium: Electronic Resource
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  • 3
    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 appearance of a significant deuterium isotope effect during the combustion of the solid HMX compound verifies that the chemical reaction kinetics is a major contributor in determining the experimentally observed or global burn rate. Burn rate comparison of HMX and its deuterium labeled HMX-d8 analogue reveals a primary kinetic deuterium isotope effect (1° KDIE) at 500 psig (3.55 MPa) and l000 psig (6.99 MPa) pressures and selectively identifies covalent carbon-hydrogen bond rupture as the mechanistic step which ultimately controls the HMX bum rate under the static combustion conditions of this experiment. The 1° KDIE value further suggests the rate-limiting C—H bond rupture occurs during the solid state HMX decomposition/deflagration portion of the overall combustion event and is supported by other independently published studies. A possible anomalous KDIE result at 1500 psig (10.4 MPa) is addressed. This condensed phase KDIE approach illustrates a direct link between lower temperature/pressure thermal decomposition and deflagration processes and their potential applicability to the combustion regime. Most importantly, a new general method is demonstrated for mechanistic combustion investigations which selectively permits an in-situ identification of the compound's burn rate-controlling step.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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