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  • 11
    Publication Date: 2018-02-20
    Description: The paper is presenting the fatigue crack growth (FCG) behavior of semi-elliptical surface cracks for API X65 gas pipeline using S-version FEM. A method known as global-local overlay technique was used in this study to predict the fatigue behavior that involve of two separate meshes each specifically for global (geometry) and local (crack). The pre-post program was used to model the global geometry (coarser mesh) known as FAST including the material and boundary conditions. Hence, the local crack (finer mesh) will be defined the exact location and the mesh control accordingly. The local mesh was overlaid along with the global before the numerical computation taken place to solve the engineering problem. The stress intensity factors were computed using the virtual crack closure-integral method (VCCM). The most important results is the behavior of the fatigue crack growth, which contains the crack depth (a), crack length (c) and stress intensity factors (SIF). The correlation betw...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 12
    Publication Date: 2015-09-08
    Description: Changes in climate and anthropogenic pressures might affect the composition and abundance of forage fish in the world's oceans. The junk-food hypothesis posits that dietary shifts that affect the quality (e.g., energy content) of food available to marine predators may impact their physiological state and consequently affect their fitness. Previously, we experimentally validated that deposition of the adrenocortical hormone, corticosterone, in feathers is a sensitive measure of nutritional stress in seabirds. Here, we use this method to examine how changes in diet composition and prey quality affect the nutritional status of free-living rhinoceros auklets ( Cerorhinca monocerata ). Our study sites included the following: Teuri Is. Japan, Middleton Is. central Gulf of Alaska, and St. Lazaria Is. Southeast Alaska. In 2012 and 2013, we collected “bill loads” delivered by parents to feed their chicks ( n  = 758) to document dietary changes. We deployed time–depth–temperature recorders on breeding adults ( n  = 47) to evaluate whether changes in prey coincided with changes in foraging behavior. We measured concentrations of corticosterone in fledgling ( n  = 71) and adult breeders' ( n  = 82) feathers to determine how birds were affected by foraging conditions. We found that seasonal changes in diet composition occurred on each colony, adults dove deeper and engaged in longer foraging bouts when capturing larger prey and that chicks had higher concentrations of corticosterone in their feathers when adults brought back smaller and/or lower energy prey. Corticosterone levels in feathers of fledglings (grown during the breeding season) and those in feathers of adult breeders (grown during the postbreeding season) were positively correlated, indicating possible carryover effects. These results suggest that seabirds might experience increased levels of nutritional stress associated with moderate dietary changes and that physiological responses to changes in prey composition should be considered when evaluating the effect of prey quality on marine predators. Changes in climate and anthropogenic activities are expected to affect diets of marine predators. Here we provide a case study of how such changes may be detected range-wide in a timely, informative, and non-invasive manner. We show that the pattern of stress hormone deposition in feathers of rhinoceros auklets breeding in coastal regions of the North Pacific reflected changes in the composition and quality of their prey.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley
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  • 13
    Publication Date: 2016-09-24
    Description: Fin whales ( Balaenoptera physalus ) undergo seasonal migration in the Arctic Sea. Because their migration and distribution is likely affected by changes in global climate, we aimed to examine the migration timing of fin whales, and the relationship with prey availability within the oceanographic environment of the Arctic Sea, using passive and active acoustic monitoring methods. Automatic Underwater Sound Monitoring Systems were deployed in the southern Chukchi Sea from July 2012 to 2014 to determine the acoustic presence of fin whales. Furthermore, water temperature and salinity were recorded by a fixed data logger. An Acoustic Zooplankton Fish Profiler was additionally deployed to estimate prey abundance through backscattering strength. Sea ice concentrations were obtained by remote sensing data. Fin whale calls were automatically detected using a custom-made software, and the per cent of half-hours containing calls were counted. Fin whale calls were detected from 4 August to 20 October 2012 (78 d) and 25 July to 1 November 2013 (100 d). The extended period of acoustic presence of fin whales during 2013 when compared with 2012 is likely related to a longer ice-free period during 2013. Furthermore, generalized linear model analyses showed that half-hour periods containing calls increased with a rise in water temperature and zooplankton abundance during the initial call presence period, while they decreased with a decrease in water temperature and salinity during the end of the call presence period. Our results suggest that the rise in water temperature and zooplankton abundance affect the timing of migration of fin whales in a way that is consistent with the expansion of their suitable habitats and the extension of their presence in the Arctic Sea.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 38 (1982), S. 1450-1451 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The photoreceptor cells in the pineal organ of the Japanese common newt are similar to typical vertebrate photoreceptors. It is supposed that the cells are responsible for the entrainment of locomotor rhythms as a consequence of their response to light.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 17 (1973), S. 41-49 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Die Lebertemperatur von männlichen Wistar Ratten in einer Klimakammer im LD 12:12 hr Licht-Dunkel Zyklus wurde mit einem Kupfer-Konstantan Thermoelement fortlaufend gemessen. Wenn die Ratten in der Lichtperiode 8°C Kälte ausgesetzt wurden, stieg die Lebertemperatur der meisten Tiere an, während sie in der Dunkelperiode in den meisten Fällen fiel. Der Reaktionsmodus des Lebertemperaturwechsels auf die Kälte ist in der Lichtperiode anders als in der Dunkelperiode. Die Reaktion scheint von der Zeit im Licht-Dunkel-Zyklus abzuhängen.
    Abstract: Resume On a mesuré la façon suivie la température du foie de rats mâles de la race de Wistar soumis, en chambre climatisée, à un cycle lumière/obscurité (L:O) de 12:12 hr. Pour ce faire, on a utilisé un couple thermo-électrique cuivreconstantan. Si l'on exposait ces animaux à une température de 8°C durant la période de lumière, la température du foie augmentait dans la plupart des cas pour s'abaisser dans l'obscurité. Le processus de variation due au froid de la température du foie est différente à la lumière de ce qu'il est dans l'obscurité. Cette réaction semble en outre dépendre du cycle LO.
    Notes: Abstract Liver temperatures of male Wistar rats were measured continuously by a copper-constantan thermocouple in a climatic chamber under LD 12:12 hr light-dark cycle. When rats were exposed to cold of 8°C in the light period, liver temperature rose in the majority of the animals, while it fell in a dark period in most cases. It was found that the response of liver temperature change to cold exposure in a light period was distinct from that in a dark period. Further, it was suggested that the response varied with time in the light-dark cycle.
    Type of Medium: Electronic Resource
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  • 17
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 10 (1983), S. 16-20 
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Shock-loading experiments are performed on single-crystal specimens of BaZnGeO4 (BZG) between 13 and 51 GPa using a propellant gun and a two-stage light gas gun. Observation by an optical microscope reveals that all the shocked specimens are made of fragmented blocks of 10 ∼ 100 μm in size. X-ray analyses indicate that the samples shocked to pressures above 41 GPa became a polycrystalline state of BZG with a weakly textured structure. A small amount of dissociation products of BaGeO3 (pyroxene type) and ZnO (wurtzite type) are detected in this pressure range. Between 27 and 19 GPa, a new phase which is thought to be produced by considerable deformations in the ring structure consisting of ZnO4 and GeO4 tetrahedra is observed. Below 19 GPa, shocked specimens are brought into a well aligned mosaic structure, but no significant change in the crystal structure is detected.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1981), S. 2137-2144 
    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 Diffusion couples of Al2O3 single-crystal, sapphire, and Nb polycrystal were heat-treated in the temperature range 1873 to 2073 K under pressure in the range 3 to 15.2 MN m−2 for various times up to 3.6×103 sec. Tensile testing at various temperatures up to 1873 K in a vacuum of about 10−3 Pa, Knoop hardness testing at room temperature, optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron-probe X-ray microanalysis studies were carried out on the specimens. From the results, it was concluded that the fairly high bond strength of a Al2O3-Nb interface might be attributed to the formation of a thin NbO x layer, which had grown epitaxially on the Al2O3 surface. Lattice matching between Al2O3 and NbO x phases was also considered.
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The feasibility of using acoustic-emission techniques for the characterization of fracture resistance in AISI 4340 and SA533B steels is examined. The critical value of J-integral (J IC ) is measured with a single small specimen (compact tension) loaded in the elastic-plastic range at room temperature. Initiation is detected during loading by acoustic emission. A new AE procedure for crack-growth monitoring in fracture-toughness specimens has been proposed. The possibility of discriminating AE signals from noncritical sources, such as void nucleation during crack-tip plastic deformation and signals from a growing crack, is discussed.
    Type of Medium: Electronic Resource
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