1,317 research outputs found
Report of the Terrestrial Bodies Science Working Group. Volume 2: Mercury
The objectives and rationale for scientific investigation of Mercury are explored. Knowledge already obtained by astronomical observations and Mariner 10 spacecraft is reviewed and measurements required for the principal scientific goals are described. The use of low thrust propulsion systems is recommended so that maximum scientific return may be achieved and the reconnaissance phase of Mercury exploration may be completed in a single mission. Accelerated development is recommended on solar electric propulsion, solar sails, passive and active cooling mechanisms, and single rough landers
Report of the Terrestrial Bodies Science Working Group. Volume 7: The Galilean satellites
The formational and evolutionary history of natural satellites, their mineralogical composition and other phenomena of scientific interest are discussed. Key scientific questions about IO, Ganymede, Callisto, and Europa are posed and the measurements and instruments required for a Galilean satellite lander in the 1980's are described
Report of the Terrestrial Bodies Science Working Group. Volume 4: The moon
A rationale for furture exploration of the moon is given. Topics discussed include the objectives of the lunar polar orbiter mission, the mission profile, and general characteristics of the spacraft to be used
VETA x ray data acquisition and control system
We describe the X-ray Data Acquisition and Control System (XDACS) used together with the X-ray Detection System (XDS) to characterize the X-ray image during testing of the AXAF P1/H1 mirror pair at the MSFC X-ray Calibration Facility. A variety of X-ray data were acquired, analyzed and archived during the testing including: mirror alignment, encircled energy, effective area, point spread function, system housekeeping and proportional counter window uniformity data. The system architecture is presented with emphasis placed on key features that include a layered UNIX tool approach, dedicated subsystem controllers, real-time X-window displays, flexibility in combining tools, network connectivity and system extensibility. The VETA test data archive is also described
Research of the thorium purification at monazite refinement processes
This paper is aimed to the research of the thorium purification processes at monazite refinement processes. We have investigated different solution containing thorium with different mix of rare-earth elements. It was found that the application of cation resin is well- recommended if we want to reach the highest yields of thorium purification process
Hermitian Young Operators
Starting from conventional Young operators we construct Hermitian operators
which project orthogonally onto irreducible representations of the (special)
unitary group.Comment: 15 page
QCD-supression by Black Hole Production at the LHC
Possible consequences of the production of small black holes at the LHC for
different scenarios with large extra dimensions are investigated. The effects
from black hole production on some standard jet observables are examined,
concentrating on the reduction of the QCD cross section. It is found that black
hole production of partons interacting on a short enough distance indeed seem
to generate a drastic drop in the QCD cross section. However from an
experimental point of view this will in most cases be camouflaged by energetic
radiation from the black holes
Diffusion and Deformations in Heterosystems with GaN/AlN Superlattices, According to Data from EXAFS Spectroscopy
Multilayered samples with extremely narrow GaN
quantum wells in an AlN host are synthesized
via ammonia MBE. The parameters of the microstructu
re are determined by means of EXAFS spectroscopy,
high-resolution electron microscopy, and low-angle sc
attering. Their relationship to the morphology of
GaN/AlN superlattices is established. The influence of
growth conditions and the thickness of superlattices
on their optical properties and mixing in the near-boundary layers is established
High surface area activated carbon prepared from wood-based spent mushroom substrate for supercapacitors and water treatment
Edible white-rot fungi are commonly cultivated on wood-based substrates and selectively degrade lignin to a larger extent during their growth. Spent mushroom substrate (SMS) is produced in huge amounts by the mushroom industry and today there is a lack of proven methods to valorize this kind of biomass waste, which in most cases is landfilled or used as fuel. This study demonstrates that birch wood-based SMS from the cultivation of oyster mushrooms can be converted into high-quality activated carbon (AC) with an extremely high surface area of about 3000 m2 /g. These activated carbons showed good performance when used in electrodes for supercapacitors, with energy storage parameters nearly identical to AC produced from high-quality virgin birch wood. Moreover, AC produced from SMS showed high potential as an adsorbent for cleaning reactive orange-16 azo dye from aqueous solutions as well as contaminants from synthetic effluents and from real sewage water. The kinetics of adsorption were well represented by the Avrami fractional order model and isotherms of adsorption by the Liu model. The theoretical maximum reactive orange-16 adsorption capacities were approximately 519 mg/g (SMS-based carbon) and 553 mg/g (virgin birch-based carbon). The removal of contaminants from synthetic effluents made of different dyes and inorganic compounds was around 95% and 83% depending on the effluent composition. The removal of contaminants from raw sewage water was around 84%, and from treated sewage water was around 68%. Overall, the results showed that activated carbon prepared from waste generated during cultivation of white-rot fungi is as good as activated carbon prepared from high-quality virgin wood
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