5,764 research outputs found
Apollo 15 rake sample microbreccias and non-mare rocks: Bulk rock, mineral and glass electron microprobe analyses
Quantitative electron microprobe data of Apollo 15 nonmare rake samples are presented. Bulk analyses of lithic fragments in the nomare rocks (expressed in oxide weight-percent) and the corresponding CIPW molecular norms are given. The mineralogy of the rocks and lithic fragments are also given; structural formulae for complete analyses and molecular end-members for all mineral analyses are included. The mineral analyses include pyroxene, olivine, plagioclase, barian K-feldspar, spinel and ilmenite, cobaltian metallic nickel-iron as well as SiO2-K2O-rich residual glass. Electron micropobe analyses (oxide weight percent) of glasses in loose fines and microbreccia samples and their CIPW molecular norms are presented along with electron microprobe data on bulk, mineral, and matrix glass from chondrules
Environments for sonic ecologies
This paper outlines a current lack of consideration for the environmental context of Evolutionary Algorithms used for the generation of music. We attempt to readdress this balance by outlining the benefits of developing strong coupling strategies between agent and en- vironment. It goes on to discuss the relationship between artistic process and the viewer and suggests a placement of the viewer and agent in a shared environmental context to facilitate understanding of the artistic process and a feeling of participation in the work. The paper then goes on to outline the installation ‘Excuse Me and how it attempts to achieve a level of Sonic Ecology through the use of a shared environmental context
Manuscript for the Proceedings of the VI International Conference on High Energy Accelerators: Improvement possibilities in the performance of the CERN Intersecting Storage Rings
Usos potenciales de la madera de roble europeo y fresno americano cultivados en la provincia de Buenos Aires, Argentina
- Spavento, E. Ing. Forestal, Docente-Investigadora, Xilotecnología y Profesional Independiente. Facultad de Ciencias Agrarias y Forestales, UNLP. [email protected]
- Keil, G. Ing. Forestal M. Sc., Docente-Investigador, Xilotecnología e Industrias de Transformación Mecánica. Facultad de Ciencias Agrarias y Forestales, UNLP. [email protected]
- Murace, M. Licenciada en Biología, Docente-Investigadora, Protección Forestal. Facultad de Ciencias Agrarias y Forestales, UNLP. [email protected]
- Luján M . Doctora en Ciencias Naturales, Docente-Investigadora, Facultad de Ciencias Naturales y Museo, UNLP. CIC, PBA.
- Bertoli, B Ingeniero Forestal, Profesional Independiente.Los usos de una madera están estrechamente relacionados a sus características tecnológicas. Para utilizar con fiabilidad la madera de roble europeo (Quercus robur L.) y fresno americano (Fraxinus pennsylvanica Marsh.) cultivada en la provincia de Buenos Aires (Argentina) es necesario conocer sus propiedades físicomecánicas y su durabilidad. El objetivo de este trabajo fue determinar, mediante ensayos estandarizados, las características tecnológicas de la madera de roble y fresno, implantados en la provincia de Buenos Aires, con el propósito de definir sus usos. Las propiedades físicas determinadas fueron: contenido de humedad (IRAM 9532), densidades aparentes (IRAM 9544), cambios dimensionales (IRAM 9543). Las propiedades mecánicas determinadas fueron: dureza Janka (IRAM 9570), flexión estática (IRAM 9542), corte paralelo a las fibras (IRAM 9596), compresión perpendicular y paralela a las fibras (IRAM 9547 y 9541 respectivamente). La durabilidad natural se estimó aplicando la norma IRAM 9518. Se estudió además la estructura del leño de ambas especies, a nivel macro y microscópico, con el fin de relacionar estas características con las propiedades tecnológicas. Para ello se cuantificaron los siguientes caracteres: longitud, espesor de pared y diámetro del lumen de fibras y diámetro de vasos mayores. Ambas maderas resultaron medianamente estables, de densidad media alta y durables. De acuerdo con esto las maderas de roble europeo y fresno americano cultivadas en Argentina son aptas para una amplia gama de usos: elementos deportivos, mangos de herramientas, muebles, escaleras, molduras, puertas, solados interiores y exteriores y elementos estructurales como vigas y columnas, entre otros
Evolution of Proto-Neutron stars with kaon condensates
We present simulations of the evolution of a proto-neutron star in which
kaon-condensed matter might exist, including the effects of finite temperature
and trapped neutrinos. The phase transition from pure nucleonic matter to the
kaon condensate phase is described using Gibbs' rules for phase equilibrium,
which permit the existence of a mixed phase. A general property of neutron
stars containing kaon condensates, as well as other forms of strangeness, is
that the maximum mass for cold, neutrino-free matter can be less than the
maximum mass for matter containing trapped neutrinos or which has a finite
entropy. A proto-neutron star formed with a baryon mass exceeding that of the
maximum mass of cold, neutrino-free matter is therefore metastable, that is, it
will collapse to a black hole at some time during the Kelvin-Helmholtz cooling
stage.
The effects of kaon condensation on metastable stars are dramatic. In these
cases, the neutrino signal from a hypothetical galactic supernova (distance
kpc) will stop suddenly, generally at a level above the background in
the SuperK and SNO detectors, which have low energy thresholds and backgrounds.
This is in contrast to the case of a stable star, for which the signal
exponentially decays, eventually disappearing into the background. We find the
lifetimes of kaon-condensed metastable stars to be restricted to the range
40--70 s and weakly dependent on the proto-neutron star mass, in sharp contrast
to the significantly larger mass dependence and range (1--100 s) of
hyperon-rich metastable stars.Comment: 25 pages, 14 figures. Submitted to Astrophysical Journa
Bunch Trains for LEP
Since 1995 LEP has been operated with a bunch train scheme which allows head-on collisions of four trains of up to four bunches within a train. The proposal and its implementation are presented, and the consequences for the beam dynamics are discussed in detail. In particular the side effects due to the separation scheme itself and the parasitic beam-beam encounters are computed. The necessity of a self consistent treatment is shown and emphasis is placed on a comparison between the expectations and the observations
Experience with Bunch Train in LEP
Since 1995 LEP is operated with the new bunch train scheme. This scheme allows head-on collisions of four trains of up to four bunches within a train. The first experience with this new scheme and the problems encountered during the commissioning and the operation are reviewed and discussed. The performance of LEP and the results from dedicated experiments are shown and compared with expectations. The modifications and improvements to allow a successful operation at LEP2 energies are discussed and the performance at energies above 80 GeV is presented
Neutrino Coherent Scattering Rates at Direct Dark Matter Detectors
Neutrino-induced recoil events may constitute a background to direct dark
matter searches, particularly for those detectors that strive to reach the
ton-scale and beyond. This paper discusses the expected neutrino-induced
background spectrum due to several of the most important sources, including
solar, atmospheric, and diffuse supernova neutrinos. The largest rate arises
from B produced solar neutrinos, providing upwards of events
per ton-year over all recoil energies for the heaviest nuclear targets. However
the majority of these B events are expected to be below the recoil
threshold of modern detectors. The remaining neutrino sources are found to
constitute a background to the WIMP-induced recoil rate only if the
WIMP-nucleon cross section is less than pb. Finally the sensitivity
to diffuse supernova neutrino flux for non-electron neutrino flavors is
discussed, and projected flux limits are compared with existing flux limits
Trapping cold atoms using surface-grown carbon nanotubes
We present a feasibility study for loading cold atomic clouds into magnetic
traps created by single-wall carbon nanotubes grown directly onto dielectric
surfaces. We show that atoms may be captured for experimentally sustainable
nanotube currents, generating trapped clouds whose densities and lifetimes are
sufficient to enable detection by simple imaging methods. This opens the way
for a novel type of conductor to be used in atomchips, enabling atom trapping
at sub-micron distances, with implications for both fundamental studies and for
technological applications
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