Chariocrinus japonicus, a new species of isocrinid crinoid (Articulata) from the Lower Cretaceous of Takayama City, central Japan
A specimen, originally described as ‘Pentacrinus’ from the Middle–Upper Jurassic of central Japan, is re-analysed and now recognised to be a new species of the genus Chariocrinus Hess, 1972, from the Lower Cretaceous. Chariocrinus japonicus sp. nov. has nine columnals per noditaxis, low columnal height, a pentalobate to sub-pentagonal articular facet and an impersistent median ridge on the latera. Chariocrinus was originally described from the Middle Jurassic of Switzerland, and has also been recognised from elsewhere in Europe, Antarctica and North America. The Japanese specimen represents the first report of Chariocrinus in the Cretaceous of Asia, thereby significantly extending both its temporal and eastern geographical range. This specimen suggests Chariocrinus had a global distribution and, as such, conforms with the distribution of other Mesozoic and modern isocrinine genera.
Nielsenicrinus japonicus new species (Echinodermata: Crinoidea) from the Late Cretaceous of Japan and its paleobiogeographic implications
A new isocrinine species, Nielsenicrinus japonicus, is described from the Maastrichtian of western Kyushu, Japan. This is the first confirmed occurrence of this genus outside Europe. Three isocrinine genera, Nielsenicrinus, Cainocrinus, and Teliocrinus, have a common arrangement of ligamentary articulations in the primibrachials and secundibrachials. These taxa possibly constitute a single lineage since the Early Cretaceous through the Recent, and they were known only from Eurasia, or from Indian Ocean (Teliocrinus).
Thermally Induced Dynamics of Satellite Solar Panels
Thermally induced structural motions are known to affect the attitude dynamics of low Earth orbiting satellites during eclipse transitions. Motions of e exible appendages such as solar panels lead to rigid body rotations of the entire satellite because the total angular momentum of the system is conserved. These potentially large attitude disturbances may violate pointing accuracy and jitter requirements. One type of thermally induced dynamics exhibited by solar panels is thermal snap. The Upper Atmosphere Research Satellite is a prominent example of a satellite that experiences thermal snap disturbances during eclipse transitions. This paper describes recent studies of thermally induced dynamicsof solarpanels, including an analysisofsatelliteattitudedynamics resulting from thermally induced structural motions and a laboratory investigation of the thermal-structural performance of a satellite solar panel. Analytical and experimental results demonstrate thermal bending deformations with acceleration transients that have characteristic thermal snap disturbance histories in response to rapid changes in heating. The studies show that solar panel thermal snap disturbances are caused by through-the-thickness temperature differences that vary at a nonconstant rate. Finite element analysis correctly predicts the thermal snap phenomenon observed in the solar panel experiments.