1,964 research outputs found
A singular structure: Monopost made in composites
p. 3002-3012This work presents the design process, the analysis, and the performance of a cylindrical hollow monopost, made entirely in composites. It is about a translucent structure of height 40m, external diameter 1.60m and the average wall-thickness 11mm. The material is a polymer made up of vinylster resin and reinforced by glass fiber (GFRP). The manufactured processing used is filament winding. Moreover, due to geographical emplacement where it is situated, the structure has to support wind velocity value above 180Km/h and its elastic modulus of the material does not exceed 25GPa. Eventually, we was able to achieve an optimum solution and strentgh structure, considering and developing differents types of approaches and analysis, such as linear, non-linear and buckling.Rovira, JA.; Martin, P.; Pons, D.; Almerich Chulia, AI. (2009). A singular structure: Monopost made in composites. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/670
Ionization states of metallic elements in a quiescent prominence
Inthe frame of the Joint Observing Program 133, which was run during the 6th MEDOC Campaign, a quiet prominence was observed on the 1st of November 2000, between17:30-20:00 UT. From the data we obtained, we want to characterize the emission line profiles and to study the different ionization states of many chemical elements present in the cool plasma of the observed prominence. We also intend to analyze the macroscopic velocities of the material and compare the results with theoretical calculations
The Importance of Campos Ecosystem as a World Food Producer and as a Provider of Ecosystem Services
The Campos ecosystem represent one of the largest grassland areas on the world, with great biodiversity in plants and animals. It contributes to improve world food security, based on ruminant livestock production, providing animal protein to feed more than 160.000.000 people. The research agenda for Campos ecosystem demands attention on the productivity and increasing variability phenomena, overgrazing, biodiversity standards and water contamination among other factors. It provides services including genetic resources, carbon storage, control of soil erosion, nutrient recycling, water production with low nutrient concentration and pest control. Overall, there is available technology to improve long-term livestock productivity and preserve current environmental indicators and improve sustainability, contributing to supply increasing world food demand
Exchange coupling inversion in a high-spin organic triradical molecule
The magnetic properties of a nanoscale system are inextricably linked to its
local environment. In ad-atoms on surfaces and inorganic layered structures the
exchange interactions result from the relative lattice positions, layer
thicknesses and other environmental parameters. Here, we report on a
sample-dependent sign inversion of the magnetic exchange coupling between the
three unpaired spins of an organic triradical molecule embedded in a
three-terminal device. This ferro-to-antiferromagnetic transition is due to
structural distortions and results in a high-to-low spin ground state change in
a molecule traditionally considered to be a robust high-spin quartet. Moreover,
the flexibility of the molecule yields an in-situ electric tunability of the
exchange coupling via the gate electrode. These findings open a route to the
controlled reversal of the magnetic states in organic molecule-based
nanodevices by mechanical means, electrical gating or chemical tailoring
Tidally Heated Exomoons around Eridani b: Observability and prospects for characterization
Exomoons are expected to orbit gas giant exoplanets just as moons orbit solar
system planets. Tidal heating is present in solar system satellites and it can
heat up their interior depending on their orbital and interior properties. We
aim to identify a Tidally Heated Exomoon's (THEM) orbital parameter space that
would make it observable in infrared wavelengths with MIRI/JWST around
Eridani b. We study the possible constraints on orbital eccentricity
and interior properties that a successful THEM detection in infrared
wavelengths can bring. We also investigate what exomoon properties need to be
independently known in order to place these constraints. We use a coupled
thermal-tidal model to find stable equilibrium points between the tidally
produced heat and heat transported within a moon. For the latter, we consider a
spherical and radially symmetric satellite with heat being transported via
magma advection in a sub-layer of melt (asthenosphere) and convection in the
lower mantle. We incorporate uncertainties in the interior and tidal model
parameters to assess the fraction of simulated moons that would be observable
with MIRI. We find that a THEM orbiting Eridani b with an
eccentricity of 0.02, would need to have a semi-major axis of 4 planetary
Roche-radii for 100% of the simulations to produce an observable moon. These
values are comparable with the orbital properties of gas giant solar system
satellites. We place similar constraints for eccentricities up to 0.1. We
conclude that if the semi-major axis and radius of the moon are known (eg. with
exomoon transits), tidal dissipation can constrain the orbital eccentricity and
interior properties of the satellite, such as the presence of melt and the
thickness of the melt containing sub-layer
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