87,787 research outputs found
Lithology and palynology of cave floor sediment cores from Wakulla Spring, Wakulla County, Florida
Five short bottom sediment cores taken in Wakulla Spring Wakulla County, Florida, were described lithologically
and sampled for palynological study. Four of the cores were recoveredfrom sediments at the spring cave entrance
(130 feet water depth). One core was taken in a fossil vertebrate bone bed, 280 feet distance into the main spring
cave at a water depth of 240 feet. Sediments in the cores are composed of alternating intervals of quartz sand and
calcilitite, containing freshwater diatoms, freshwater mollusk shells and plant remains. The predominant pollen
present in all cores consists of a periporate variety typical of the herb families Chenopodiaceae and Amaranthaceae.
Arboreal flora, typical of the area surrounding the spring today, represent a very low percentage of thle pollen
assemblage in the cores. Clustered Chenopod-Amaranth type pollen observed in one core suggest minimal transport
prior to deposition, and indicate that the bottom sediments in the cave may be essentially In situ. An absence of
exotic flora suggests a Quaternary age for the sediments. (PDF contains 11 pages.
Study of high temperature bearing materials
Experimental investigation identifies materials suitable for use in potassium lubricated turbo-generator journal bearing and shaft applications at high temperatures. Attention is given to nonrefractory metals and alloys, refractory metals and alloys, Fe-Ni-Co bonded carbides, refractory compounds, and refractory metal bonded carbides
Randomly interacting bosons, mean-fields and L=0 ground states
Random interactions are used to investigate to what extent the low-lying
behavior of even-even nuclei depend on particular nucleon-nucleon interactions.
The surprising results that were obtained for the interacting boson model, i.e.
the dominance of ground states with L=0 and the occurrence of both vibrational
and rotational structure, are interpreted and explained in terms of a
mean-field analysis.Comment: 6 pages, 2 figures, Invited talk at NP2001, Goettingen, March 2001,
World Scientific (2001), in pres
Collective states from random interactions
The anharmonic vibrator and rotor regions in nuclei are investigated in the
framework of the interacting boson model using an ensemble of random one- and
two-body interactions. Despite the randomness of the interactions (in sign and
size) we find a predominance of L(P)=0(+) ground states and strong evidence for
the occurrence of both vibrational and rotational band structure.Comment: 4 pages, 2 figures, 1 tables, to be published in the proceedings of
Bologna 200
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