1,298 research outputs found
The Evolutionary Unified Scheme. I. Quasars and Radio Galaxies in the Viewing Angle - Redshift Plane
We present a study of the distribution of quasars and radio galaxies in the
plane (viewing angle - redshift) in the framework of the evolutionary unified
scheme (Vagnetti et al. 1991). Results are presented for some illustrative
cases, including a distribution of the Lorentz factors, and appropriate
luminosity functions for quasars and their host galaxies. A cosmologically
increasing is found, in agreement with the previous paper. It is argued
that the appearence of sources as quasars or radio galaxies can depend on the
viewing angle and on the redshift, due to the balance between the beamed
component and the luminosity of the host galaxy. Within the assumptions of our
evolutionary unified scheme, we find that low-Gamma objects can be observed as
quasars mainly at z<~0.3, while a substantial fraction of the low-z radio
galaxies could consist of quasar-remnants.Comment: to appear in ApJ; 18 pages, uuencoded-compressed-tarred PostScript
file including figures; ROM2F/94/1
Drive Train Normal Modes Analysis for the ERDA/NASA 100-Kilowatt Wind Turbine Generator
Natural frequencies, as a function of power were determined using a finite element model. Operating conditions investigated were operation with a resistive electrical load and operation synchronized to an electrical utility grid. The influence of certain drive train components on frequencies and mode shapes is shown. An approximate method for obtaining drive train natural frequencies is presented
Dynamic blade loading in the ERDA/NASA 100 kW and 200 kW wind turbines
Dynamic blade loads, including aerodynamic, gravitational, and inertial effects, are presented for two large horizontal-axis wind turbines: the ERDA-NASA 100 kW Mod-0 and 200 kw Mod-0A wind power systems. Calculated and measured loads are compared for an experimental Mod-0 machine in operation. Predicted blade loads are also given for the higher power Mod-0A wind turbine now being assembled for operation as part of a municipal power plant. Two major structural modifications have been made to the Mod-0 wind turbine for the purpose of reducing blade loads. A stairway within the truss tower was removed to reduce the impulsive aerodynamic loading caused by the tower wake on the downwind rotor blades. Also, the torsional stiffness of the yaw drive mechanism connecting the turbine nacelle to the tower was doubled to reduce rotor-tower interaction loads. Measured reductions in load obtained by means of these two modifications equaled or exceeded predictions
High performance astrophysics computing
The application of high end computing to astrophysical problems, mainly in
the galactic environment, is under development since many years at the Dep. of
Physics of Sapienza Univ. of Roma. The main scientific topic is the physics of
self gravitating systems, whose specific subtopics are: i) celestial mechanics
and interplanetary probe transfers in the solar system; ii) dynamics of
globular clusters and of globular cluster systems in their parent galaxies;
iii) nuclear clusters formation and evolution; iv) massive black hole formation
and evolution; v) young star cluster early evolution. In this poster we
describe the software and hardware computational resources available in our
group and how we are developing both software and hardware to reach the
scientific aims above itemized.Comment: 2 pages paper presented at the Conference "Advances in Computational
Astrophysics: methods, tools and outcomes", to be published in the ASP
Conference Series, 2012, vol. 453, R. Capuzzo-Dolcetta, M. Limongi and A.
Tornambe' ed
Solos do Assentamento Mato Grande - Corumbá, MS: caracterização, limitações e aptidão agrícola.
Argissolos; Cambissolos; Luvissolos; Neossolos; Planossolos; Vertissolos; Aptidão agrícola das terras; Inserção do agricultor no mercado.bitstream/item/37736/1/DOC27.pd
Solos do Assentamento Urucum - Corumbá, MS: caracterização, limitações e aptidão agrícola.
Cambissolos; Chernossolos; Luvissolos; Neossolos; Vertissolos; Aptidão agrícola das terras; Inserção do agricultor no mercado.bitstream/item/37731/1/DOC30.pd
Preliminary analysis of performance and loads data from the 2-megawatt mod-1 wind turbine generator
Preliminary test data on output power versus wind speed, rotor blade loads, system dynamic behavior, and start-stop characteristics on the Mod-1 wind turbine generator are presented. These data were analyzed statistically and are compared with design predictions of system performance and loads. To date, the Mod-1 wind turbine generator has produced up to 1.5 MW of power, with a measured power versus wind speed curve which agrees closely with design. Blade loads were measured at wind speeds up to 14 m/s and also during rapid shutdowns. Peak transient loads during the most severe shutdowns are less than the design limit loads. On the inboard blade sections, fatigue loads are approximately equal to the design cyclic loads. On the outboard blade sections, however, measured cyclic loads are significantly larger than design values, but they do not appear to exceed fatigue allowable loads as yet
Solos do Assentamento Taquaral - Corumbá, MS: caracterização, limitações e aptidão agrícola.
Cambissolos; Chernossolos; Vertissolos; Aptidão agrícola das terras; Inserção do agricultor no mercado.bitstream/item/37733/1/DOC29.pd
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