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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of natural products 44 (1981), S. 27-33 
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 38 (1982), S. 229-229 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An acidic fraction of Panamenian variant ofCannabis sativa L., afforded upon repeated chromatography a new non-cannabinoid phenol {5′-hydroxy-7′-methoxy spiro-(cyclohexane-1, 1′-indan)-4-one}Ia, named iso-cannabispiran.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 20 (1997), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— Simple extensions to the standard deep notch bend test procedure are suggested to allow the collection of data relevant to the energy dissipation rate, D, crack opening angle, COA, and J, all for arbitrarily large amounts of growth in extensive plasticity. The methods of analysis are detailed for real elastic-plastic behaviour of a high strength low-hardening type metal with a view to encouraging use on a wider range of materials. A proposal is made, and equations given, that the particular version of J used for an R-curve derived from the area under the loading diagram, should correspond to the value of the far-field integral, Jff.The relationship between the global measure of COA that emerges from D and the local crack tip opening angle, CTOA, as used in computational studies, is established. Transferability of CTOA data is examined in the light of effects of size and configuration. An explicit rule of the form CTOA √G =f (material and configuration) is proposed for the modelling of ductile growth in finite element studies. It is applied to a set of data in the literature, for the variation of CTOA with size in the deep notch bend test and for the configurations, bending, double edge and centre cracked tension.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 17 (1994), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The equations for the energy dissipation rate, D per unit area of crack growth, for plasticity and fracture combined, are presented for equilibrium crack extension in a real elastic-plastic material. These relationships are a necessary condition for stable growth. The term D is identical to G for lefm and to the rate at which work is done for the rigid-plastic limit. Crack growth is seen at both micro- and macro-levels as a two stage process of damage accumulation in a process zone followed by actual separation as a micro-instability at the crack tip. Some examples of the behaviour of ductile metals are cited in support at both micro- and macro-level. For the fully plastic case, D reduces strongly with growth. Relationships with conventional rising R-curves are stated for contained and uncontained yield.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 17 (1994), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— Equations are established for the final macro-unstable behaviour of a fully plastic cracked component in terms of the energy dissipation rate. Control by this first differential of energy occurs when the second differential of the energy absorbed is negative, a condition easily met for crack growth in certain fully plastic cases. The driving force for the instability is a term, I that becomes greater than the lefm term, G, as plasticity occurs. The additional component is an exchange of elastic to plastic energy, a term that is system dependent and is thus the main driving force for a fully plastic ductile instability. A possible relevance to brittle fracture and to a system dependence of both initiation toughness and the whole crack growth resistance curve is discussed.
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 13 (1990), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Data from a study of the effect of geometric variation on J-R curves for a titanium alloy in three-point bending are presented up to large amounts of growth. Four series are reported, various widths, various a/W ratios, various thicknesses and various absolute sizes, all failing in the limit load regime by stable tearing. Analysis is made in terms of Jm-R curves, adjusted to a common initiation toughness, J1, to clarify the effects of geometry. Strong trends are then found with absolute size over a four fold range and with width over a two fold range; a weaker trend with a/W over a four fold range but practically none with thickness over a nine fold range. Many of these trends are different from those reported for other more ductile materials but consistent in some cases with those reported for another high strength material, HY130. All the deep notch cases (14 tests) reduce to a single group when plotted as Jm against a normalised abscissa, Δa/bo, with a very slight trend to a higher curve for the thinner pieces.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 17 (1994), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— Energy dissipation rate, D, and crack tip opening angle (CTOA) have been related for large amounts of ductile crack growth in a fully plastic two-dimensional model of real elastic plastic material. Several J-type rising R-curves have been constructed and related, some based on the cumulative energy dissipated and some as a characterising term that relates closely to the far-field J contour value. These two meanings co-exist but the relationship is geometry dependent. For deep notch bend (DNB) cases the non-dimensional group Lα/r* (where L is normalised load, α is CTOA and r* defines the position of the instantaneous centre of rotation) governs the value of dJ. Certain DNB cases where R-curves vary with size are resolved by this group rather than by CTOA itself whereas for centre-cracked tension there is a higher value of CTOA than for DNB.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 20 (1985), S. 3081-3090 
    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 Toughness was measured and crack growth resistance curves determined on BS4360:50D steel, over a range of orientations and temperatures from + 20 to − 50° C in terms of both J-integral and crack opening displacement (COD) values, for a number of configurations in static bending. All fractures occurred in a ductile micro-mode. The results are discussed here only in terms of J, but several different methods of estimation are used. These fall into two main groups: for measurement of work done, the results are some 10% higher than those determined from load and clip gauge. Values of J IC found according to the standard ASTM method were some 30% higher than a value for no growth. Maximum load toughness was about twice the JIC value. Over the range studied (0.3 〈 a/W 〈 0.5; W/2 〈 B 〈 W; 20 mm 〈 B 〈 50 mm; Δa/b 〈 0.1 where a is crack length, W and B specimen width and thickness, and b=W−a) both J and COD values depended strongly on orientation, but J by either type of analysis was invariant with respect to temperature and sensitive to geometry only in respect of thickness in one case. Conditions of testing do not therefore seem at all critical in this regime, although the values found depend on the methods of analysis used.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 33 (1977), S. 848-848 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ethanol extract of Cannabis sativa L. afforded upon partitioning and repeated chromatography a new non-cannabinoid phenol [7′-hydroxy-5′-methoxy-spiro-(cyclohexane-1, 1′-indan)-4\-ol](IIIa), named β-cannabispiranol.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 35 (1979), S. 1131-1132 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Total synthesis of cannabispiran (1) was accomplished by a biomimetic-type cyclization of the bibenzyl2, using K3Fe(CN)6 or MoOCl4.
    Type of Medium: Electronic Resource
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