602 research outputs found
Customized WO3 nanoplatelets as visible-light photoelectrocatalyst for the degradation of a recalcitrant model organic compound (methyl orange)
WO3 nanoplatelets have been synthesized by electrochemical anodization in acidic electrolytes containing two different complexing agents: fluorides and hydrogen peroxide. The influence of the morphology and size of these nanoplatelets on their photoelectrocatalytic performance has been studied following the degradation of a model organic recalcitrant compound, such as methyl orange (MO). The effect of several supporting electrolytes on this photodegradation process has also been checked. The best MO decoloration was observed for nanoplatelets fabricated in the presence of low H2O2 concentrations, whose distribution and small size made them expose a very high surface area to the problem solution. With this nanostructure, decoloration efficiencies of ca. 100% were obtained after just 60 min. This result is considerably better than others reported in similar works, indicating the excellent behavior of these WO3 nanoplatelets as photoelectrocatalysts
Análisis del potencial de ahorro mediante la aplicación de medidas de rehabilitación energética
CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En este artículo se presentan dos nuevas herramientas web que permiten cuantificar el potencial de rehabilitación en edificios residenciales del Principado de Asturias. La mejora energética se ha calculado mediante una metodología de simulación que identifica los casos más representativos, analiza su comportamiento energético través del acoplamiento entre TRNSYS y GenOpt, y realiza un post-procesado para calcular los potenciales finales. Se han identificados dos categorías de viviendas: unifamiliares y bloques de cuatro, siete y diez plantas; dos configuraciones para las condiciones de contorno: aisladas y adosadas; cuatro normativas edificatorias y varios porcentajes de sombra en las ventanas. Los mayores potenciales de rehabilitación se obtienen para las viviendas unifamiliares más antiguas, disminuyendo a medida que aumentan los requisitos normativos. Los bloques de viviendas presentan similares patrones pero con porcentajes inferiores. Finalmente, las configuraciones aisladas alcanzan mayores potenciales frente a las adosadas.ABSTRACT: This article presents two new web tools that allow quantifying the refurbishment potential in residential buildings in the Principado de Asturias. The energy savings have been calculated using a simulation methodology that identifies the most representative cases, analyzes their energy performance through the coupling between TRNSYS and GenOpt, and performs post-processing analyses to calculate the final potentials. Two categories of buildings have been identified: single-family and blocks of four, seven and ten floors; two configurations for boundary conditions: isolated and semi-detached or linear; four building regulations and various percentages of shade in windows. The greatest refurbishment potentials are obtained for older single-family dwellings, decreasing as regulatory requirements increase. Similar patterns are reached by blocks but with lower percentages. Finally, isolated configurations achieve higher potentials compared to semi-detached or linear configurations.info:eu-repo/semantics/publishedVersio
Practical guide for earthquake resilient schools
This guide is intended to be a resource, and not a manual, for increasing the resilience of an educational community, by showing the community what they can do on their own account and how they can strengthen their ability to handle seismic risk (for example, being informed and familiarised with the characteristics that affect the vulnerability of an area in the event of an earthquake, and prepared to protect the students under their tutelage before the earth shakes).POCTEP-INTERREG España-Portugal e Fundo Europeu de Desenvolvimento Regional (FEDER); 0313_PERSISTAH_5_P, Projetos de Escolas Resilientes aos Sismos no Território do Algarve e de Huelvainfo:eu-repo/semantics/publishedVersio
Why does the ground shake?
This manual is designed to support the training of primary school teachers, instructors and technicians, who want to improve their knowledge and develop activities about seismic and tsunami risk. The contents and information of this document come from researches carried out at present, and also as the continuation of other projects in which the author has participated, such as the game "Treme-Treme".POCTEP-INTERREG España-Portugal e Fundo Europeu de Desenvolvimento Regional (FEDER)info:eu-repo/semantics/publishedVersio
Maximally-localized Wannier functions for entangled energy bands
We present a method for obtaining well-localized Wannier-like functions (WFs)
for energy bands that are attached to or mixed with other bands. The present
scheme removes the limitation of the usual maximally-localized WFs method (N.
Marzari and D. Vanderbilt, Phys. Rev. B 56, 12847 (1997)) that the bands of
interest should form an isolated group, separated by gaps from higher and lower
bands everywhere in the Brillouin zone. An energy window encompassing N bands
of interest is specified by the user, and the algorithm then proceeds to
disentangle these from the remaining bands inside the window by filtering out
an optimally connected N-dimensional subspace. This is achieved by minimizing a
functional that measures the subspace dispersion across the Brillouin zone. The
maximally-localized WFs for the optimal subspace are then obtained via the
algorithm of Marzari and Vanderbilt. The method, which functions as a
postprocessing step using the output of conventional electronic-structure
codes, is applied to the s and d bands of copper, and to the valence and
low-lying conduction bands of silicon. For the low-lying nearly-free-electron
bands of copper we find WFs which are centered at the tetrahedral interstitial
sites, suggesting an alternative tight-binding parametrization.Comment: 13 pages, with 9 postscript figures embedded. Uses REVTEX and epsf
macro
A new variational approach to the stability of gravitational systems
We consider the three dimensional gravitational Vlasov Poisson system which
describes the mechanical state of a stellar system subject to its own gravity.
A well-known conjecture in astrophysics is that the steady state solutions
which are nonincreasing functions of their microscopic energy are nonlinearly
stable by the flow. This was proved at the linear level by several authors
based on the pioneering work by Antonov in 1961. Since then, standard
variational techniques based on concentration compactness methods as introduced
by P.-L. Lions in 1983 have led to the nonlinear stability of subclasses of
stationary solutions of ground state type.
In this paper, inspired by pioneering works from the physics litterature
(Lynden-Bell 94, Wiechen-Ziegler-Schindler MNRAS 88, Aly MNRAS 89), we use the
monotonicity of the Hamiltonian under generalized symmetric rearrangement
transformations to prove that non increasing steady solutions are local
minimizer of the Hamiltonian under equimeasurable constraints, and extract
compactness from suitable minimizing sequences. This implies the nonlinear
stability of nonincreasing anisotropic steady states under radially symmetric
perturbations
Coronin-1C Protein and Caveolin Protein Provide Constitutive and Inducible Mechanisms of Rac1 Protein Trafficking
Sustained directional fibroblast migration requires both polarized activation of the protrusive signal, Rac1, and redistribution of inactive Rac1 from the rear of the cell so that it can be redistributed or degraded. In this work, we determine how alternative endocytic mechanisms dictate the fate of Rac1 in response to the extracellular matrix environment. We discover that both coronin-1C and caveolin retrieve Rac1 from similar locations at the rear and sides of the cell. We find that coronin-1C-mediated extraction, which is responsible for Rac1 recycling, is a constitutive process that maintains Rac1 protein levels within the cell. In the absence of coronin-1C, the effect of caveolin-mediated endocytosis, which targets Rac1 for proteasomal degradation, becomes apparent. Unlike constitutive coronin-1C-mediated trafficking, caveolin-mediated Rac1 endocytosis is induced by engagement of the fibronectin receptor syndecan-4. Such an inducible endocytic/degradation mechanism would predict that, in the presence of fibronectin, caveolin defines regions of the cell that are resistant to Rac1 activation but, in the absence of fibronectin leaves more of the membrane susceptible to Rac1 activation and protrusion. Indeed, we demonstrate that fibronectin-stimulated activation of Rac1 is accelerated in the absence of caveolin and that, when caveolin is knocked down, polarization of active Rac1 is lost in FRET experiments and culminates in shunting migration in a fibrous fibronectin matrix. Although the concept of polarized Rac1 activity in response to chemoattractants has always been apparent, our understanding of the balance between recycling and degradation explains how polarity can be maintained when the chemotactic gradient has faded
Guia prático escola resiliente aos sismos
Este Guia pretende ser um recurso para aumentar a resiliência da comunidade educativa, mostrando que é possível viver com os sismos e que se tomarmos medidas preventivas os riscos de perdas e ferimentos reduzem bastante.
Como uma emergência pode acontecer em qualquer lugar e a qualquer momento, é importante que a comunidade educativa, esteja informada e familiarizada com o que torna um espaço vulnerável em caso de sismo, e se preparem para proteger as crianças sob seus cuidados antes que a terra trema.Projeto PERSISTAH, Projetos de Escolas Resilientes aos SIsmos no
Território do Algarve e de Huelva (0313_PERSISTAH_5_P), desenvolvido em conjunto pelas universidades do
Algarve e Sevilha e financiado pela Comissão Europeia através do programa EP – INTERREG VA Espanha
Portugal (POCTEP).info:eu-repo/semantics/publishedVersio
Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV
We report the results of a study of color coherence effects in ppbar
collisions based on data collected by the D0 detector during the 1994-1995 run
of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8
TeV. Initial-to-final state color interference effects are studied by examining
particle distribution patterns in events with a W boson and at least one jet.
The data are compared to Monte Carlo simulations with different color coherence
implementations and to an analytic modified-leading-logarithm perturbative
calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters
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