525 research outputs found
Lunar surface engineering properties experiment definition Quarterly report, 1 Oct. - 31 Dec. 1968
Mechanical properties of simulated lunar soil
Cohomology of finite dimensional pointed Hopf algebras
We prove finite generation of the cohomology ring of any finite dimensional
pointed Hopf algebra, having abelian group of grouplike elements, under some
mild restrictions on the group order. The proof uses the recent classification
by Andruskiewitsch and Schneider of such Hopf algebras. Examples include all of
Lusztig's small quantum groups, whose cohomology was first computed explicitly
by Ginzburg and Kumar, as well as many new pointed Hopf algebras. We also show
that in general the cohomology ring of a Hopf algebra in a braided category is
braided commutative. As a consequence we obtain some further information about
the structure of the cohomology ring of a finite dimensional pointed Hopf
algebra and its related Nichols algebra.Comment: 36 pages, references adde
Material studies related to lunar surface exploration Technical summary report, 6 Mar. 1967 - 30 Jun. 1968
Summary of research studies on lunar surface material propertie
Material studies related to lunar surface exploration. Volume 4 - Preliminary studies for the design of engineering probes Final report, 6 Mar. 1967 - 30 Jun. 1968
Preliminary design of engineering probes for studying lunar surface material propertie
Material studies related to lunar surface exploration, volume 3 Final report, 6 Mar. 1967 - 30 Jun. 1968
Mechanical properties of lunar soils related to lunar exploratio
Material studies related to lunar surface exploration. Volume 2 - Application of geophysical and geotechnical methods to lunar sites exploration Final report, 6 Mar. 1967 - 30 Jun. 1968
Geophysical and geotechnical methods for lunar landing site soil property studie
Material studies related to lunar surface exploration. Volume 1 - Lunar soil mechanics and soil properties Final report, 6 Mar. 1967 - 30 Jun. 1968
Lunar soil mechanics and properties for structural engineering aspects of lunar spacecraft landings and surface exploratio
Dcse Estimation and Prediction of Radiation Effects on Aquatic Biota Resulting from Radioactive Releases .from the Nuclear Fuel Cycle*
ABSTRACT -NOTICE vepott was rnir . prepared as an accou.T of work S'Cut efponsibuity for the accuracy, completeness « uJulnas of any information, apparatus, product o process disclosed, or represents that its use would not d iht process disclo, p infringe privately owned lights. Aquatic organisms are exposed to radionuclides released to the environment during various steps of the nuclear fuel cycle. Routine releases from these processes are limited in compliance with technical specifications, requirements of federal regulations. These regulations reflect I.C.R.P. recommendations which are designed to provide an environment considered safe for man. It is generally accepted that aquatic organisms will not receive damaging external radiation doses in such environments; however, because of possible bioaccunulation of radionuclides there is concern that aquatic organisms might be adversely affected 'ay internal doses. The objectives of this paper are: (1) to estimate the radiation dose received by aquatic biota from the different processes and determine the major dose-contributing radionuclides, and (2) to assess the impact of estimated doses on aquatic biota. Dose estimates are made by using radionuclide concentration measured in the liquid effiuents of representative facilities. Where measurements of concentrations are rot available, predicted radioactive releases to the aquatic environment are used for dose calculations. Although radioactive releases from reactors used to generate electrical energy have received the most attention, and are the best documented, this evaluation indicates the potential for a greater radiation dose to aquatic biota from the nuclear fuel supply facilities (i.e., mining and milling).. The effects of chronic low-level radiation on aquatic organisms are discussed from somatic and genetic viewpoints. Based on the body of radiobiological evidence accumulated up to the present time, no significant deleterious effects are predicted for populations of aquatic organisms exposed to the estimated dose rates resulting from routine releases from conversion, enrichment, fabrication, reactors and reporcessing facilities. At the doses estimated for milling and mining operations it would be difficult to detect radiation effects on aquatic populations; however, the significance of such radiation exposures to aquatic populations cannot be fully evaluated without further research on effects of chronic low-level radiation
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