266 research outputs found
Convective Heat Transfer Coefficient in a Bubbling Fluidized Bed with PCM
Proceedings of: 14th International Conference on Fluidization: From Fundamentals to Products. Noordwijkerhout, Netherlands, 26-31 may 2013.This work presents an experimental study to determine the capacity of a Phase Change Material (PCM) in granular form to be used in a bubbling fluidized bed for thermal energy storage. The experimental measurements are focused on the determination of the heat transfer coefficient between a heated surface and the granular PCM in fluidized state. The results obtained indicates that the heat transfer coefficient notably increases (up to values three times higher) when the granular PCM is in solid form because it changes its phase when touches the heated surfaceThis work was partially founded by the Spanish Government (Project ENE2010-15403), the regional Government of Castilla-La Mancha (Project PPIC10-0055-4054) and Castilla-La Mancha University (Project GE20101662).publicad
Design, manufacturing and set-up tests of a wave energy converter prototype in the context of the European Project LIFE-Demowave
LifeDemoWave Project is a real case of development of a R&D project, from the initial idea to the final construction and installation of a prototype for testing in operational environment. This project was born from an idea of the main researcher of the CIMA Group that finally led to two patents of two wave generation systems. Based on these patents, CIMA sought different ways for funding with the aim of developing prototypes with a high TRL and being able to test the operating principle of the patented systems. Finally, funding was obtained through the Life Program of the European Union and in collaboration with five other partners. The main objective of the LifeDemoWave project (http://www. life-demowave.eu/en/) is the demonstration of the feasibility of the use of wave power for electric generation in order to reduce greenhouse gases' emissions. For demonstration purposes, prototypes of wave power generation, reproducible and scalable at high level, are installed in the Galician coast. LifeDemoWave project considers, as well as its design and implementation, the environmental impact in the installation areas and its effect on biodiversity.Peer Reviewe
Rhodium complexes in p-C bond formation: Key role of a hydrido ligand
Olefin hydrophosphanation is an attractive route for the atom-economical synthesis of functionalized phosphanes. This reaction involves the formation of P-C and H-C bonds. Thus, complexes that contain both hydrido and phosphanido functionalities are of great interest for the development of effective and fast catalysts. Herein, we showcase the excellent activity of one of them, [Rh(Tp)H(PMe3)(PPh2)] (1), in the hydrophosphanation of a wide range of olefins. In addition to the required nucleophilicity of the phosphanido moiety to accomplish the P-C bond formation, the key role of the hydride ligand in 1 has been disclosed by both experimental results and DFT calculations. An additional Rh-H··· C stabilization in some intermediates or transition states favors the hydrogen transfer reaction from rhodium to carbon to form the H-C bond. Further support for our proposal arises from the poor activity exhibited by the related chloride complex [Rh(Tp)Cl(PMe3)(PPh2)] as well as from stoichiometric and kinetic studies
Experimental Studies of Phase Change Materials in a Bubbling Fluidized Bed
Proceedings of: 14th International Conference on Fluidization: From Fundamentals to Products. Noordwijkerhout, Netherlands, 26-31 may 2013.The aim of this work is to experimentally study the behaviour of three microencapsulated PCM in a bubbling fluidized bed for thermal energy storage. Different experiments, heating and cooling the granular PCM with fluidizing air, are carried out with different superficial gas velocities. When achieving their phase change temperature two of the three materials present agglomeration. For this reason, the material flowability and wear resistance are studied by measuring the angle of repose and attrition, respectively. Nevertheless, the angle of repose does not seem to be influenced by the temperature of the material and the particle size distributions after the attrition tests indicate that the bed particles are just slightly smaller than the original ones.This work was partially founded by the Spanish Government (Project ENE2010-15403), the regional Government of Castilla-La Mancha (Project PPIC10-0055-4054) and Castilla-La Mancha University (Project GE20101662).Publicad
Hidden supersymmetries in supersymmetric quantum mechanics
We discuss the appearance of additional, hidden supersymmetries for simple
0+1 -invariant supersymmetric models and analyse some geometrical
mechanisms that lead to them. It is shown that their existence depends
crucially on the availability of odd order invariant skewsymmetric tensors on
the (generic) compact Lie algebra , and hence on the cohomology
properties of the Lie algebra considered.Comment: Misprints corrected, two refs. added. To appear in NP
Expansions of algebras and superalgebras and some applications
After reviewing the three well-known methods to obtain Lie algebras and
superalgebras from given ones, namely, contractions, deformations and
extensions, we describe a fourth method recently introduced, the expansion of
Lie (super)algebras. Expanded (super)algebras have, in general, larger
dimensions than the original algebra, but also include the Inonu-Wigner and
generalized IW contractions as a particular case. As an example of a physical
application of expansions, we discuss the relation between the possible
underlying gauge symmetry of eleven-dimensional supergravity and the
superalgebra osp(1|32).Comment: Invited lecture delivered at the 'Deformations and Contractions in
Mathematics and Physics Workshop', 15-21 January 2006, Mathematisches
Forschungsinstitut Oberwolfach, German
Supergravity interacting with bosonic p-branes and local supersymmetry
We study the coupling of supergravity with a purely bosonic brane source
(bosonic p-brane). The interaction, described by the sum of their respective
actions, is self-consistent if the bosonic p-brane is the pure bosonic limit of
a super-p-brane. In that case the dynamical system preserves 1/2 of the local
supersymmetry characteristic of the `free' supergravity.Comment: 11 pages, RevTe
Balancing consistency and expert judgment in AHP
The various mechanisms that represent the know-how of decision-makers are exposed to a common weakness, namely, a lack of consistency. To overcome this weakness within AHP (analytic hierarchy process), we propose a framework that enables balancing consistency and expert judgment. We specifically focus on a linearization process for streamlining the trade-off between expert reliability and synthetic consistency. An algorithm is developed that can be readily integrated in a suitable DSS (decision support system). This algorithm follows an iterative feedback process that achieves an acceptable level of consistency while complying to some degree with expert preferences. Finally, an application of the framework to a water management decision-making problem is presented. (C) 2010 Elsevier Ltd. All rights reserved.Thanks to the support of the project IDAWAS, DPI2009-11591, of the Spanish Direccion General de Investigacion of the Ministerio de Ciencia e Innovacion, and ACOMP/2010/146 of the Conselleria de Educacion of the Generalitat Valenciana. The use of English in this paper was revised by John Rawlins.Benítez López, J.; Delgado Galván, XV.; Gutiérrez-Pérez, JA.; Izquierdo Sebastián, J. (2011). Balancing consistency and expert judgment in AHP. Mathematical and Computer Modelling. 54(7-8):1785-1790. https://doi.org/10.1016/j.mcm.2010.12.023S17851790547-
Macrofauna asociada al alga stypocaulon scoparium en el Estrecho de Gibraltar y comparación con el resto de la Península Ibérica
Se estudió la macrofauna asociada al alga Stypocaulon scoparium en el estrecho de Gibraltar y el resto de la
península Ibérica. Se seleccionaron un total de 14 estaciones, 3 de ellas localizadas en el Estrecho y las 11
restantes distribuidas en las costas cantábricas, atlánticas y mediterráneas de la península Ibérica. En cada
estación se midieron parámetros fisicoquímicos (temperatura, oxígeno disuelto, conductividad, pH y
turbidez), se estimó la cobertura del alga y se recolectaron muestras de la misma en el submareal somero (1-
3 m de profundidad) mediante buceo en apnea. Se separaron e identificaron un total de 48.430 individuos
pertenecientes a 16 grupos distintos de artrópodos, moluscos, anélidos y equinodermos. Atendiendo a los
parámetros fisicoquímicos, los análisis de clasificación mostraron una mayor similaridad del área del
Estrecho con las estaciones atlánticas. La costa mediterránea se caracterizó por una mayor temperatura y
conductividad, mientras que la atlántica mostró valores más altos de oxígeno disuelto y turbidez,
consecuencia un mayor oleaje. La cobertura del alga S. scoparium fue significativamente mayor en el
Estrecho de Gibraltar que en las estaciones restantes y se registró una mayor diversidad de invertebrados
asociados a este alga en el Estrecho que en otras zonas de la Península. Los crustáceos anfípodos fueron los
más abundantes, seguidos de poliquetos y moluscos gasterópodos. El Análisis Canónico de
Correspondencias (CCA) mostró que anfípodos, isópodos, quironómidos y crinoideos correlacionaron
principalmente con la cobertura del alga, mientras que la abundancia de gasterópodos estuvo condicionada
por la turbidez y la de los grupos restantes por la conductividad y temperatura principalmente. El estrecho d
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