Ara es mostren els items 1-19 de 19

    • A rockoon closed helium buoyancy system; a first assessment 

      Arias Montenegro, Francisco Javier (British Interplanetary Society, 2023-03-30)
      Article
      Accés restringit per política de l'editorial
      It is believed that the use of rockoons will revolutionize the space industry by giving priority service to microsatellite developers that now are secondary payloads for large rocket companies. However, stratospheric ...
    • Development of flow regime maps for lead lithium eutectic–helium flows 

      Mas de les Valls Ortiz, Elisabet; Cegielski, Andrzej; Jaros, Mark; Pérez-Ferragut, Marina; Batet Miracle, Lluís; Freixa Terradas, Jordi (2020-09-01)
      Article
      Accés obert
      nstitute for Plasma Research (IPR), Gandhinagar (India) is currently involved in the design and development of its Lead-Lithium Ceramic Breeder (LLCB) module for testing in the International Thermo-nuclear Experimental ...
    • Diseño conceptual e ingenieria de detalle de un lazo experimental dual Pb15.7Li/ He (proyecto BCN_LOOP®): una propuesta de proyecto de I+D+i industrial para desarrollos clave en tecnologia nuclear de fusion 

      Batet Miracle, Lluís; Reventós Puigjaner, Francesc Josep; Mas de les Valls Ortiz, Elisabet; Fernández, Iván; Veredas, G.; Abellà, Jordi; Sempere Cebrían, Julià; Sanmartí Cardona, Manel; Linares, José Ignacio; Sedano, L.A. (2012)
      Text en actes de congrés
      Accés obert
    • Estudi i disseny del xassís d’un dron sustentat amb gas heli 

      Traid Salmerón, Jan (Universitat Politècnica de Catalunya, 2023-07-05)
      Treball Final de Grau
      Accés restringit per acord de confidencialitat
      L'objectiu d'aquest projecte és crear un dron sostingut amb heli que potenciï i millori l'autonomia i l'adaptabilitat dels drons comercials. El dron pot volar durant períodes més llargs utilitzant heli com a agent d'elevació, ...
    • Excitonic insulator to superconductor phase transition in ultra-compressed helium 

      Liu, Cong; Errea Lope, Ion; Ding, Chi; Pickard, Chris J.; Conway, Lewis J.; Monserrat Sánchez, Bartomeu; Fang, Yue Wen; Lu, Qing; Sun, Jian; Boronat Medico, Jordi; Cazorla Silva, Claudio (2023-07-25)
      Article
      Accés obert
      Helium, the second most abundant element in the universe, exhibits an extremely large electronic band gap of about 20 eV at ambient pressures. While the metallization pressure of helium has been accurately determined, thus ...
    • First-principles modeling of three-body interactions in highly compressed solid helium 

      Cazorla Silva, Claudio; Boronat Medico, Jordi (2015-12-31)
      Article
      Accés obert
      We present a set of three-body interaction models based on the Slater-Kirkwood (SK) potential that are suitable for the study of the energy, structural, and elastic properties of solid He4 at high pressure. Our effective ...
    • Henry's constant of helium in liquid alkali metals 

      Álvarez Galera, Edgar; Laria, Daniel; Batet Miracle, Lluís; Martí Rabassa, Jordi (2024-02)
      Article
      Accés obert
      The determination of the solubility of helium in liquid lithium and in lead-lithium eutectic systems is of crucial importance for the assessment of the reliability, safety and efficiency of future nuclear reactor plants ...
    • High altitude balloon mission design and implementation for a mini-launcher 

      Bonet Osorio, Lluis (Universitat Politècnica de Catalunya, 2011-04-08)
      Treball Final de Grau
      Accés obert
      Durante muchos años, las sondas estratosféricas han sido usadas para experimentos atmosféricos. Los nuevos globos de LATEX de bajo coste permiten poner hasta 4 kilogramos de carga de pago en el espacio cercano. Típicamente, ...
    • Layering transition in superfluid helium adsorbed on a carbon nanotube mechanical resonator 

      Noury, Adrien; Vergara Cruz, Jorge; Morfin, Pascal; Plaçais, Bernard; Gordillo Bargueño, Maria Carmen; Boronat Medico, Jordi; Balibar, Sébastien; Bachtold, Adrian (American Institute of Physics (AIP), 2019-04-23)
      Article
      Accés obert
      Helium is recognized as a model system for the study of phase transitions. Of particular interest is the superfluid phase in two dimensions. We report measurements on superfluid helium films adsorbed on the surface of a ...
    • Microscopic approach to the response of 3 - 4 He mixtures 

      Fabrocini, A; Mazzanti Castrillejo, Fernando Pablo; Polls Martí, Artur (American Physical Society (APS), 1996-10-01)
      Article
      Accés obert
      Correlated-basis-function perturbation theory is used to evaluate the zero-temperature response S(q,¿) of 3-4He mixtures for inelastic neutron scattering, at momentum transfers q ranging from 1.1 to 1.8 A°-1. We adopt a ...
    • Neutron Ionization of Helium near the Neutron-Alpha Particle Collision Resonance 

      Pindzola, M. S.; Colgan, J.; Ciappina, M. F. (IOP, 2020-09-10)
      Article
      Accés obert
      Neutron-impact single and double ionization cross sections of the He atom are calculated near the neutron-alpha particle collision resonance. Calculations using the time-dependent close-coupling method for total and ...
    • Nucleation of helium in liquid lithium at 843 K and high pressures 

      Martí Rabassa, Jordi; Mazzanti Castrillejo, Fernando Pablo; Astrakharchik, Grigori; Batet Miracle, Lluís; Portos-Amill, Laura; Pedreño, Borja (Multidisciplinary Digital Publishing Institute (MDPI), 2022-04-13)
      Article
      Accés obert
      Fusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding ...
    • Nucleation of helium in pure liquid lithium 

      Álvarez Galera, Edgar; Martí Rabassa, Jordi; Mazzanti Castrillejo, Fernando Pablo; Batet Miracle, Lluís (American Institute of Physics (AIP), 2023-07-14)
      Article
      Accés obert
      Tritium self-sufficiency in fusion nuclear reactors will be based on the neutron capture by lithium in the so-called breeding blankets of the reactor, a nuclear reaction that will produce helium along with tritium. The low ...
    • On the stability of small vacancy clusters in solid 4He 

      Lutsyshyn, Yaroslav; Rota, Riccardo; Boronat Medico, Jordi (2011-03)
      Article
      Accés restringit per política de l'editorial
      We study numerically properties of multiple vacancies in solid 4He at zero temperature. Up to four vacancies were introduced into the solid through incommensuration between the number of available lattice sites and the ...
    • Partially Diffusive Helium-Silica Compound under High Pressure 

      Liu, Cong; Wang, Junjie; Deng, Xin; Wang, Xiaomeng; Pickard, Chris J.; Helled, Ravit; Wu, Zhongqing; Wang, Hui-Tian; Xing, Dingyu; Sun, Jian (Institute of Physics (IOP), 2022-06-01)
      Article
      Accés obert
      Helium is the second most abundant element in the universe, and together with silica, they are important components of giant planets. Exploring the reactivity and state of helium and silica under high pressure is crucial ...
    • Quantum halo states in helium tetramers 

      Stipanovic, P.; Vranješ Markic, Leandra; Boronat Medico, Jordi (2017-01-12)
      Article
      Accés obert
      The universality of quantum halo states enables a comparison of systems from different fields of physics, as demonstrated in two- and three-body clusters. In the present work, we studied weakly bound helium tetramers in ...
    • Quantum phase transition with a simple variational ansatz 

      Lutsyshyn, Yaroslav; Astrakharchik, Grigori; Cazorla, C; Boronat Medico, Jordi (2014-12-11)
      Article
      Accés obert
      We study the zero-temperature quantum phase transition between liquid and hcp solid He-4. We use the variational method with a simple yet exchange-symmetric and fully explicit wave function. It is found that the optimized ...
    • Structure of halo and quasi-halo helium–helium–alkali trimers 

      Stipanovic, P.; Vranješ Markic, Leandra; Boronat Medico, Jordi (2017-05-01)
      Article
      Accés obert
      We report a diffusion Monte Carlo study of A4He2 and A4He3He trimers’ structural properties, were A is one of the alkali atoms 6,7Li, 23Na, 39K, 85Rb or 133Cs. Some of them are in a pure halo state, characterized by large ...
    • The limit of mechanical stability in quantum crystals: a diffusion Monte Carlo study of solid He-4 

      Cazorla Silva, Claudio; Boronat Medico, Jordi (2015-07-01)
      Article
      Accés obert
      We present a first-principles study of the energy and elastic properties of solid helium at pressures below the range in which it is energetically stable. We find that the limit of mechanical stability in hcp He is bar, ...