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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 29 (1973), S. 715-716 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Résumé La testostérone, administrée de faćcon chronique à des souris femelles provoque und diminution statistiquement significative de l'index juxtaglomérulaire. Les femelles traitées par la progestérone ou les souris mâles et femelles des groupes contrôlés ne présentent aucune variation. Ces constatations sont discutées en relation avec l'effet de la testostérone sur le flux sanguin rénal, la pression de perfusion glomérulaire et la secrétion d'aldostérone, de rénine et d'érythropoiétine.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 19 (1984), S. 3626-3639 
    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 Titanium metal was subjected to two surface treatments (alkaline peroxide etch and chromic acid anodization) and resulting oxide morphology examined by high-resolution scanning electron microscopy in a Jeol 100-CX STEM. The effects of treatment time in alkaline peroxide upon oxide morphology were followed and parallel mechanical measurements made on the strengths of adhesive bonds between the metal and an epoxy resin. These strengths were measured after a standard environmental exposure, namely 120 h in water at 80° C. As time-of-treatment increases, a micro-porous oxide layer is developed and adhesive strength rises to a maximum. Prolonged treatment with alkaline peroxide produces a drastic fall in adhesive strength accompanied by gross etching of the metal surface without changes in the oxide morphology. The loss of adhesive durability in this case is therefore attributable to surface chemistry effects rather than morphological changes.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 20 (1985), S. 3621-3630 
    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 A modified adhesive peel test is described in which a spring is inserted between the test machine cross-head and the peeling strip. In tests using two pressure sensitive surgical adhesives (uncrosslinked elastomers) this “soft machine” gives results which differ significantly from those obtained with a conventional “hard machine”. In particular, when peeling energy is plotted against peeling velocity, the soft machine reveals a regime of low energy peeling and a transition to the normal high energy peeling. The transition behaviour has been studied as a function of adhesive thickness, cross-head speed and spring stiffness. The phenomena revealed by soft machine testing are interpreted in terms of variations in crack-tip radius caused by flow of the uncrosslinked rubber. The practical implication is that far more information can be obtained from soft machine tests than from conventional hard machine tests. The problem of oscillating peel force is also eliminated.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1996), S. 17-20 
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Degradation studies on a series of polyesterurethanes having different compositions of hard and soft blocks have been performed utilizing an accelerated test method. Degradation was followed by titrimetry, mass loss, mechanical properties and infrared spectroscopy. As the number of methylene groups present within the polyester moiety was increased, the resistance to degradation also increased. The presence of an aromatic component in the hard block reduced the rate of hydrolysis but the degradation in mechanical properties was accelerated.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 13 (1978), S. 777-785 
    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 fracture surface roughness was determined for five highly deformable polymers (styrene-butadiene rubber, two ethylene-propylene rubbers, low density polyethylene and plasticized polyvinyl chloride) as a function of rate and temperature. The mechanical hysteresis for the same materials was also measured as a function of rate, temperature and strain amplitude. Although the surface roughness does not correlate with crack velocity, it does so uniquely with the effective hysteresis in the material surrounding the propagating crack. A simple physical explanation is advanced for the universal dependence of roughness on hysteresis in these materials.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    International journal of fracture 20 (1982), S. 65-77 
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résumé On applique l'approache généralisée de la mécanique de rupture à deux aciers ductiles, à savoir l'acier doux et l'acier inoxydable 18/8 soumis à état plan de tension. La théorie définit un paramètre de rupture $$\mathcal{T}$$ qui est en fait l'homologue plastique de l'intégrale de contourJ et qui, dans le cas d'une éprouvette fissurée sur ses bords, est donnée par $$\mathcal{T} = k_1 ( \in _0 )cW_{0_c } $$ . Dans cette expression,k 1 est une fonction explicite,c est la longueur de la fissure etε 0,cW0c sont respectivement la dilation et la densité d'énergie appliquée au moment de la rupture et ce à une certaine distance de la fissure. La fonctionk 1 est dérivée par voie expérimentale et on démontre la constance de $$\mathcal{T}$$ vis-à-vis de la longueur de la fissure et de la charge appliquée. La variation de $$\mathcal{T}$$ avec l'extension de la fissure au cours de la croissance lente est étudiée ainsi que, dans le cas de l'acier doux, la dépendance de $$\mathcal{T}$$ vis-à-vis de la vitesse.
    Notes: Abstract The generalized fracture mechanics approach is applied to two ductile steels, namely mild steel and 18/8 stainless steel in plane stress. The theory defines a fracture parameter $$\mathcal{T}$$ , which is a truly plastic analogue of theJ contour integral and, for an edge crack specimen, is given by $$\mathcal{T} = k_1 ( \in _0 )cW_{0_c } $$ wherek 1 is an explicit function,c is the crack length andε 0, W0c are respectively the strain and input energy density at fracture, remote from the crack. The functionk 1(ε o) is derived experimentally and the constancy of $$\mathcal{T}$$ with respect to crack length and applied load is demonstrated. The variation of $$\mathcal{T}$$ with crack extension during slow growth is investigated, as is the rate dependence of $$\mathcal{T}$$ in mild steel.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 13 (1978), S. 1291-1302 
    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 Measurements were made of the fracture suface energy of epoxy resins above their glass transition temperatures as a function of temperature, crack velocity and resin composition. The fracture energy, ℐ, obeys the WLF time-temperature superposition principle in the same way as in more conventional elastomers. Measurements also indicate a lower limit to ℐ, designated ℐ 0, which is independent of time and temperature. A theoretical calculation of ℐ 0 agrees well with the experimental data.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 13 (1978), S. 1680-1688 
    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 fracture behaviour of an epoxy resin has been studied by a method which involves the pressurization of an internal circular crack. The method can be used to study both cohesive fracture and the adhesive failure of an interface. Plane strain conditions are assured because the crack does not intersect a free surface and (for adhesive failure) shrinkage stresses are eliminated as a crack driving force. Using high speed photography, the dependence of crack speed on critical pressure and specimen geometry was determined. An elastic analysis permits the derivation of fracture energy as a function of crack velocity. Fracture energy values lay between 100 and 200 Jm−3 at 35° C with a peak at a crack velocity of 37 m sec−1.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 18 (1983), S. 1455-1465 
    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 plane-strain fracture-energy test developed by Andrews and Stevenson has been applied to the study of ice adhering to substrates of stainless steel, titanium and anodised aluminium. In most cases the fracture is cohesive through the ice, and therefore yields a cohesive fracture energy (critical energy release rate). The value of this fracture energy, however, is dependent upon the nature of the substrate, stainless steel giving significantly lower values than titanium. The fracture energy is also affected by the rate of formation of the ice and by the rate of testing. Many of these effects can be traced to the influence of the substrate on the air-bubble content of the ice layer. At testing temperatures approaching the melting point of ice, a transition in fracture mode is observed from cohesive to adhesive, and the fracture energy diminishes. The addition of small amounts of sodium fluoride to the water from which the ice is formed, lowers the transition temperature to −5° C, and emphasizes the transition to the adhesive failure mode.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 19 (1984), S. 73-81 
    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 adhesion of ice to a flexible substrate, polyurethane elastomer, has been studied using the Andrews-Stevenson test procedure which involves the pressurization to failure of an enclosed interfacial crack. The temperature, rate of pressurization and substrate layer thickness were varied and the failure energy (critical energy release rate) determined. If energy release from the flexible substrate is ignored an apparent failure energy is obtained which first increases and then decreases as the layer thickness rises from zero to 4 mm. This thickness effect results in a large variation in the pressure needed to produce failure, and is thus important in relation to the ice-release properties of the substrate. It is shown that the thickness effect can be explained quantitatively in terms of the energy release from the flexible substrate, which, in turn, depends on its visco-elastic properties. The true failure energy is derived and is also found to correlate with the visco-elastic response of the rubber. Finally, these ideas are used to explain the effects of rate and temperature on the conditions of failure.
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