| 1. |
- Billstein, Mats, et al.
(author)
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Application and validation of a numerical model of flow through embankment dams with fractures : Comparisons with experimental data
- 1999
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In: Canadian geotechnical journal (Print). - : Canadian Science Publishing. - 0008-3674 .- 1208-6010. ; 36:4, s. 651-659
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Journal article (peer-reviewed)abstract
- The focus of this paper is on the development and validation of a numerical model of flow through simplified embankment dams with fractures. Two laboratory experiments were conducted to provide data for validation of the numerical model, one dealing with steady flow in a Hele-Shaw cell and one with steady flow through a bed of packed glass beads. A horizontal fracture, extending from the upstream boundary to a point within the embankment, was used in both experiments, and it was shown to have a significant influence on the discharge, pressure distribution, height of the seepage face, and free surface profile. Comparisons between numerically determined and experimentally measured results were carried out with respect to the discharge, pressure distribution, height of the seepage face, and free surface profile. In the experiments it is shown that a fracture increases the discharge and that the discharge increases more when a fracture is located far away from the free surface profile than when it is located close to the free surface profile. The height of the seepage face above the tailwater is strongly dependent upon the length of the fracture. The influence on the free surface profile is greater when a fracture is close to the free surface profile than when it is far away from the free surface profile. These effects are also found in the numerical simulations. It is thus concluded that the agreement is generally satisfactory between the experimental and numerical results
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| 2. |
- Billstein, Mats, et al.
(author)
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Development and Validation of a Numerical Model of Flow Through Embankment Dams – Comparisons with Experimental Data and Analytical Solutions
- 1999
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In: Transport in Porous Media. - 0169-3913 .- 1573-1634. ; 35:3, s. 395-406
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Journal article (peer-reviewed)abstract
- The development and validation of a numerical simulation model of the flow through embankment dams is described. The paper focuses on basic verification studies, that is, comparisons with analytical solutions and data from laboratory experiments. Two experimental studies, one dealing with the flow in a Hele-Shaw cell and the other with the flow through a bed of packed glass beads, are also described. Comparisons are carried out with respect to the phreatic surfaces, pressure profiles, seepage levels and discharges. It is concluded that the agreement between experimental, analytical and numerical results is generally satisfactory.
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| 3. |
- Sundstrom, Jens, et al.
(author)
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MADS-box genes active in developing pollen cones of Norway spruce (Picea abies) are homologous to the B-class floral homeotic genes in angiosperms
- 1999
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In: Developmental Genetics. - 0192-253X .- 1520-6408. ; 25:3, s. 253-266
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Journal article (peer-reviewed)abstract
- The reproductive organs of conifers, the pollen cones and seed cones, differ in morphology from the angiosperm flower in several fundamental respects. In this report we present evidence to suggest that the two plant groups, in spite of these morphological differences and the long evolutionary distance between them, share important features in regulating the development of the reproductive organs. We present the cloning of three genes, DAL11, DAL12, and DAL13, from Norway spruce, all of which are related to the angiosperm B-class of homeotic genes. The B-class genes determine the identities of petals and stamens. They are members of a family of MADS-box genes, which also includes C-class genes that act to determine the identity of carpels and, in concert with B genes specify stamens in the angiosperm flower. Phylogenetic analyses and the presence of B-class specific C-terminal motifs in the DAL protein sequences imply homology to the B-class genes. Specific expression of all three genes in developing pollen cones suggests that the genes are involved in one aspect of B function, the regulation of development of the pollen-bearing organs. The different temporal and spatial expression patterns of the three DAL genes in the developing pollen cones indicate that the genes have attained at least in part distinct functions. The DAL11, DAL12, and 13 expression patterns in the pollen cone partly overlap with that of the previously identified DAL2 gene, which is structurally and functionally related to the angiosperm C-class genes. This result supports the hypothesis that an interaction between B- and C-type genes is required for male organ development in conifers like in the angiosperms. Taken together, our data suggests that central components in the regulatory mechanisms for reproductive organ development are conserved between conifers and angiosperms and, thus, among all seed plants.
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