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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Rock mechanics and rock engineering 32 (1999), S. 169-193 
    ISSN: 1434-453X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: Summary Knowledge of in-situ stress in rock masses is essential for mining and civil engineering design and the Kaiser effect method of stress determination provides an economical alternative to currently applied investigation techniques. A practical problem associated with this method is the loss of the Kaiser effect over time during the process of anelastic strain recovery, but a direct relationship is observed between anelastic strain recovery and the number of acoustic emissions. The behaviour is modelled here using the Kelvin and Burger rheological models, for the stages of creep during uniaxial laboratory loading, anelastic strain recovery and the loss of the Kaiser effect, with constants being calculated and compared for samples loaded under geological and laboratory conditions. It is found that the loss of the KE at low stress levels compares directly with the process of anelastic strain recovery and fits the Burger model over the time scales of interest. A difference between primary and secondary (undercored samples) recovery is demonstrated with a slower recovery for primary relaxation and with samples taken from geological stress environments recovering more slowly than those loaded under laboratory conditions, for all stress levels tested.
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  • 2
    ISSN: 1432-1939
    Keywords: Key words Herbivory ; Phytochemistry ; Plant-insect interactions ; Trifolium repens ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  White clover growing in New Zealand is experiencing increasing levels of ultraviolet-B (UV-B) radiation as a result of ozone depletion. We evaluated the effects of UV-B radiation on the foliar chemistry of two populations of white clover (Trifolium repens L.), ’Huia’ and ’Tienshan,’ and the consequences for the performance of armyworms (Spodoptera litura) and cutworms (Graphania mutans). Plants were grown in controlled environment rooms with and without supplemental UV-B radiation at a dose of 13.3 kJ m–2 day–1, corresponding to a 25% mid-summer ozone depletion above Palmerston North, New Zealand. In both white clover populations, UV-B radiation elicited changes in foliar chemistry, including slight increases in nitrogen concentrations and decreases in carbohydrate concentrations. In addition, the ’Huia’ population showed decreases in fiber concentrations and marked increases in cyanogenic activity. No change in UV-absorbing compounds was detected in either population. Long- and short-term feeding trials were conducted to assess dietary effects on insect growth, consumption, and food utilization. Changes in the performance of both insect species were generally small. The most pronounced effect was a 36% reduction in weight of S. litura after 2 weeks of feeding on Huia grown at high UV, but larval development times were only slightly prolonged and pupal weights were unaffected. S. litura short-term performance was affected by differences in white clover population. The long-term performance of G. mutans was not affected and its short-term performance (stadium duration and consumption rate) was only marginally affected by the high-UV treatment. We conclude that the effects of elevated UV-B radiation on white clover plant chemistry can be specific to certain plant populations. The differences in sensitivity of the two generalist insect species suggest that effects may also be specific to certain plant-herbivore associations. These results indicate that future UV-B herbivory studies should examine genotypic effects in both plants and animals.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 23 (1989), S. 323-333 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Non-linearity of softwood in axial mechano-sorptive creep during moisture cycling can be characterised as departure from linear behaviour. Linear behaviour is shown by experimental measurement to be a gradual approach to a creep limit with exponentially decreasing increments of compliance, Ji, per moisture cycle, when tested under a constant stress. On the other hand, when the stress is progressively increased by a small increment Δσ after each moisture cycle, the compliance increments will progressively increase, having a value of $$\Delta \sigma \sum\limits_1^n {{\text{J}}_{\text{i}} }$$ , where n is the cycle number. By subtracting one compliance increment from the succeeding one, the value of Δσ Ji can be obtained. Analysis of experimental results in bending tension and compression showed that the compression test pieces departed from linearity at total strains around 0.14% to 0.15%, the bending test pieces showed slight evidence of non-linearity at about the same strain, whilst the tensile pieces were approximately linear up to 0.18% strain.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 22 (1988), S. 199-210 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary An adaptor for the conversion of a high-accuracy tensile creep machine to compression loading is described. It was found that a stable mechano-sorptive creep limit could be obtained by a suitable load reduction after moisture cycling; after which further creep and creep recovery just balanced each other. In this stable state the value of the longitudinal moisture-swelling coefficient depended on the strain; being less with tensile strain and more with compressive strain then in the unloaded condition. These differences in the swelling coefficient could explain the apparent recovery during subsequent sorptions in mechanosorptive creep in bending. Such a hypothesis was strongly supported by numerical comparisons of strains in bending, tension and compression.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 31 (1997), S. 3-16 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The author gives numerical data resulting from detailed measurements on a common softwood,Picea abies; which can form the basis for the verification of new structural models of wood cell walls. Some suggestions are made for the interpretation of the data, including the development of internal stresses followed by relaxation, molecular destabilisation followed by physical aging during moisture changes, and differing forms of moisture bonding.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 32 (1998), S. 57-70 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary This paper describes the study of possible interactions between the viscoelastic and mechano-sorptive creep inPinus sylvestris. When two periods of constant-moisture creep were separated by a period of mechano-sorptive creep, the expected creep rate during the second viscoelastic period was decreased. A similar effect was observed during creep recovery. These results were taken to indicate an interaction between the two types of creep, although not necessarily a common mechanism. During recovery with uniform moisture cycling, the effects of one extra low and one extra high humidity were observed. The low humidity showed no significant effect, but the high humidity significantly increased the recovery. This was attributed to a parallel effect to that of creep: namely, the creep acceleration that occurs at a higher moisture level than has previously been reached during the test.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Optical and quantum electronics 20 (1988), S. 87-93 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
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  • 8
    ISSN: 1573-5192
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Acugutturus parasiticus n.g., n.sp. is described from St. Lucia, W. Indies. The species is unique in the Aphelenchoidea because of the 50 to 60 μm stylet with the conus much longer than the shaft. A. parasiticus is ectoparasitic on Periplaneta americana (L.), all stages of the nematode, including the egg, being found on the body surfaces. Acugutturinae n.subf. is proposed to accommodate the new genus.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Systematic parasitology 5 (1983), S. 215-221 
    ISSN: 1573-5192
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Indiana gryllotalpae is redescribed from the gut of a mole-cricket, Scapteriscus sp., from Trinidad. The structure of the cephalic umbraculum (comprising 6 major and 6 minor cuticular elements extending back from the setulose lip region) is described in detail by use of both light and scanning electron microscopy. I. gryllotalpae of Bain (1965) is regarded as a synonym of I. coimbatoriensis Latheef & Seshadri, 1972. ac]19820729
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-5192
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Four new species of hystrignathid nematodes are described from the midgut caeca of Passalus unicornus (Coleoptera: Passalidae) from St. Lucia, West Indies. Artigasia horridospina n.sp. is differentiated from A. dispar van Waerebeke, 1973 by virtue of fewer rows of spines in the oesophageal region and in possessing lateral alae, and from A. insignia Travassos & Kloss, 1958 in the extent of the oesophageal spiens and in having the lateral alae commence more anteriorly. The first annule is also much shallower than that of A. insignia. Longior semialata n.sp. is differentiated from L. longicollis Travassos & Kloss, 1958 on body length, ‘b’ ratio, egg size and the starting point of the lateral alae. Mentecle magnifica n.sp. differs from M. parvus Travassos & Kloss, 1958 in having the spines of the oesophageal region extending much further down the body and in having ridged eggs. It is also longer and relatively thinner. Paraxyo ensicrinatus n.sp. differs from P. monodelpho Travassos & Kloss, 1958 in having a proportionately longer tail. The spines in the oesophageal region also extend considerably further posteriorly than in P. monodelpho. Two ‘types’ of male associated with the above nematodes are described and illustrated, but not assigned to females. Pulchrocephala? pulchrocephala Travassos, 1925 is redescribed from the gut of the mole-cricket Scapteriscus vicinus. Scanning electron micrographs of four of the described species are given and briefly discussed. ac]19801024
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