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  • 1
    Digitale Medien
    Digitale Medien
    The effectiveness of various nitrogen sources in white spruce [Picea glauca (Moench) Voss] somatic embryogenesis (1997)
    Springer
    Plant cell reports 16 (1997), S. 411-415 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Somatic embryogenesis ; Picea glauca ; Nitrogen nutrition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of glutamine-based dipeptides, glutamine and casein hydrolysate, as well as the deletion of organic nitrogen, were investigated during white spruce [Picea glauca (Moench) Voss] somatic embryogenesis. There were no differences in the fresh weight increase of the tissue masses grown on initiation medium with different combinations of organic nitrogen. This was also the case for subsequent growth on kinetin medium, except that glutamine alone produced a significantly lower fresh weight increase than the other organic nitrogen combinations. Without organic (i.e. with only inorganic) nitrogen in the medium, the fresh weight increase was significantly less than with organic nitrogen on both initiation and kinetin medium. No differences were found between the dry/fresh weight ratios obtained with the various nitrogen treatments. The number of mature embryos produced per gram fresh weight when cultured in the absence of organic nitrogen was significantly higher than that obtained in its presence. There were no differences in the total number of mature embryos produced in cultures grown with various organic nitrogen combinations or without organic nitrogen. There were large clone differences with respect to the number of mature somatic embryos per gram tissue and the total number of somatic embryos produced. Hence, nitrogen type influences culture growth rate but not the number of mature somatic embryos produced. The latter was clone dependent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01146784
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  • 2
    Digitale Medien
    Digitale Medien
    Somaclonal variation in cryopreserved embryogenic clones of white spruce [Picea glauca (Moench) Voss.] (1999)
    Springer
    Plant cell reports 18 (1999), S. 948-953 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Key words Somaclonal variation ; Picea glauca ; RAPD ; Somatic embryogenesis ; Cryopreservation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Trees were regenerated from six white spruce embryogenic clones after cryopreservation for 3 and 4 years, respectively. Genetic stability was evaluated using randomly amplified polymorphic DNA (RAPD) fingerprints. Somaclonal variation was detected in some in vitro embryogenic cultures 2 and 12 months after they were re-established following cryopreservation but not in the corresponding regenerated trees. These results suggest that trees regenerated from cryopreserved cultures in subsequent years are primarily genetically stable in the genomic regions tested and that variation observed due to the in vitro culture process infrequently affects trees regenerated from normally maturing and germinating somatic embryos. However, trees regenerated from somatic embryos that matured or germinated abnormally in in vitro culture exhibited altered RAPD fragment patterns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002990050689
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  • 3
    Digitale Medien
    Digitale Medien
    The effectiveness of various nitrogen sources in white spruce [Picea glauca (Moench) Voss] somatic embryogenesis (1997)
    Springer
    Plant cell reports 16 (1997), S. 411-415 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Key words Somatic embryogenesis ; Picea glauca ; Nitrogen nutrition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of glutamine-based dipeptides, glutamine and casein hydrolysate, as well as the deletion of organic nitrogen, were investigated during white spruce [Picea glauca (Moench) Voss] somatic embryogenesis. There were no differences in the fresh weight increase of the tissue masses grown on initiation medium with different combinations of organic nitrogen. This was also the case for subsequent growth on kinetin medium, except that glutamine alone produced a significantly lower fresh weight increase than the other organic nitrogen combinations. Without organic (i.e. with only inorganic) nitrogen in the medium, the fresh weight increase was significantly less than with organic nitrogen on both initiation and kinetin medium. No differences were found between the dry/fresh weight ratios obtained with the various nitrogen treatments. The number of mature embryos produced per gram fresh weight when cultured in the absence of organic nitrogen was significantly higher than that obtained in its presence. There were no differences in the total number of mature embryos produced in cultures grown with various organic nitrogen combinations or without organic nitrogen. There were large clone differences with respect to the number of mature somatic embryos per gram tissue and the total number of somatic embryos produced. Hence, nitrogen type influences culture growth rate but not the number of mature somatic embryos produced. The latter was clone dependent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01146784
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  • 4
    Digitale Medien
    Digitale Medien
    Modeling lumber strength spatial variation using trend removal and kriging analyses (1992)
    Springer
    Wood science and technology 26 (1992), S. 369-381 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary The techniques of kriging and trend removal analysis for modeling the strength properties of lumber have been discussed. Using these techniques, the within member compressive strengths of 38 mm × 89 mm 2100f-1.8E and the within member tensile strengths of 38 mm × 89 mm No. 2 spruce-pine-fir lumber have been modeled. The suitability of these techniques to model the strength properties of lumber has been evaluated by comparing the kriged compressive and tensile strength data to baseline experimentally collected compressive strength data and simulated tensile strength data, respectively. Comparisons of the results of statistical analyses of the baseline data and the kriged data show good agreement. The use of kriging and trend removal techniques to generate strength values in simulation studies for finite element analyses of wood structures is judged to be effective.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226078
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  • 5
    Digitale Medien
    Digitale Medien
    Wood as a linear orthotropic viscoelastic material (1972)
    Springer
    Wood science and technology 6 (1972), S. 43-57 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary Measurements were made of the principal components of the creep compliance tensor in the radial-longitudinal and the tangential-longitudinal planes of Douglas-fir at 10 percent moisture content. Extensional creep compliance measurements at angles to the grain were also made. The results show that creep parallel to grain occurs at an increase in volume, and that creep at angles to the grain can be predicted from standard transformation equations. It is concluded that wood can be regarded as a linear orthotropic viscoelastic material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00351807
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  • 6
    Digitale Medien
    Digitale Medien
    Incorporating size effects in the Tsai-Wu strength theory for Douglas-fir laminated veneer (1998)
    Springer
    Wood science and technology 32 (1998), S. 215-226 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary This paper elucidates the need to consider the effect of volume on brittle material strengths when these strengths are used in a strength theory. Specifically, Weibull weakest-link theory has been implemented with the Tsai-Wu strength theory to predict the ultimate load carrying capacity of a center point off-axis bending member made from Douglas-fir laminated veneer. Weibull theory has been used in two distinct ways to account for size effects needed to evaluate brittle material strengths (ie. tension perpendicular and parallel to grain, and shear) for the strength criterion. The analytical methods assume linear elastic, plane stress states and have been described and evaluated using probability theory as a framework. Analytical results are in reasonable agreement with experimental findings substantiating the techniques proposed herein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00704844
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  • 7
    Digitale Medien
    Digitale Medien
    Bending strength adjustments for moisture content for structural lumber (1991)
    Springer
    Wood science and technology 25 (1991), S. 433-447 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary Effects of moisture content on bending strength and section capacity have been studied assuming that strength properties are linearly related to moisture content below the fiber saturation point. The models developed using the linear strength vs. moisture content relationships are compared with quadratic models developed earlier. The linear representation of strength variation with moisture content leads to predicted member bending capacity relationships which show that increases in member bending strength with moisture content will compensate for section property decreases at all bending strength property levels. Comparisons of bending strength and bending capacity models show that the two modelling approaches lead to similar predicted member performance. Simplified procedures are provided for adjusting member bending strength for moisture content which are suitable for materials properties codes or standards.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00225236
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  • 8
    Digitale Medien
    Digitale Medien
    Modified algorithm to determine localized modulus of elasticity of lumber (1993)
    Springer
    Wood science and technology 27 (1993), S. 81-94 
    Details
    ISSN: 1432-5225
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary A procedure has been developed to determine the cut-off frequency in an algorithm to evaluate the localized modulus of elasticity (MOE) in lumber. MOE profiles have been artificially generated to serve as input for evaluation of the procedure. A noise component has also been added to the input record to test the robustness and accuracy of the procedure. Good agreement between program predictions and the known localized MOE values has been obtained. The efficiency of the procedure has also been tested using MOE profiles collected from experiments. The program performed efficiently and program predictions seemed reasonable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00206227
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  • 9
    Digitale Medien
    Digitale Medien
    Incorporating size effects in the Tsai-Wu strength theory for Douglas-fir laminated veneer (1998)
    Springer
    Wood science and technology 32 (1998), S. 215-226 
    Details
    ISSN: 0043-7719
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Maschinenbau
    Notizen: Summary This paper elucidates the need to consider the effect of volume on brittle material strengths when these strengths are used in a strength theory. Specifically, Weibull weakest-link theory has been implemented with the Tsai-Wu strength theory to predict the ultimate load carrying capacity of a center point off-axis bending member made from Douglas-fir laminated veneer. Weibull theory has been used in two distinct ways to account for size effects needed to evaluate brittle material strengths (ie. tension perpendicular and parallel to grain, and shear) for the strength criterion. The analytical methods assume linear elastic, plane stress states and have been described and evaluated using probability theory as a framework. Analytical results are in reasonable agreement with experimental findings substantiating the techniques proposed herein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00704844
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  • 10
    Digitale Medien
    Digitale Medien
    Optimal design of pitched laminated wood beams (1978)
    Springer
    Journal of optimization theory and applications 26 (1978), S. 291-303 
    Details
    ISSN: 1573-2878
    Schlagwort(e): Geometric programming ; signomial programming ; structural design ; optimal engineering design
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract The optimal design of a pitched laminated wood beam is considered. An engineering formulation is given in which the volume of the beam is minimized. The problem is then reformulated and solved as a generalized geometric (signomial) program. Sample designs are presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00933409
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