The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Tetsuya Uda - One of the best experts on this subject based on the ideXlab platform.

  • multi step hydration dehydration mechanisms of rhombohedral y2 so4 3 a candidate material for low temperature thermochemical heat storage
    RSC Advances, 2020
    Co-Authors: Kunihiko Shizume, Naoyuki Hatada, Shoko Yasui, Tetsuya Uda
    Abstract:

    To evaluate rhombohedral Y2(SO4)3 as a new potential material for low-temperature thermochemical energy storage, its thermal behavior, phase changes, and hydration/dehydration reaction mechanisms are investigated. Rhombohedral Y2(SO4)3 exhibits reversible hydration/dehydration below 130 °C with relatively small thermal hysteresis (less than 50 °C). The reactions proceed via two reaction steps in approximately 0.02 atm of water vapor pressure, i.e. “high-temperature reaction” at 80–130 °C and “low-temperature reaction” at 30–100 °C. The high-temperature reaction proceeds by water insertion into the rhombohedral Y2(SO4)3 Host Structure to form rhombohedral Y2(SO4)3·xH2O (x = ∼1). For the low-temperature reaction, rhombohedral Y2(SO4)3·xH2O accommodates additional water molecules (x > 1) and is eventually hydrated to Y2(SO4)3·8H2O (monoclinic) with changes in the Host Structure. At a water vapor pressure above 0.08 atm, intermediate Y2(SO4)3·3H2O appears. A phase stability diagram of the hydrates is constructed and the potential usage of Y2(SO4)3 for thermal energy upgrades is assessed. The high-temperature reaction may act similarly to an existing candidate, CaSO4·0.5H2O, in terms of reaction temperature and water vapor pressure. Additionally, the hydration of rhombohedral Y2(SO4)3·xH2O to Y2(SO4)3·3H2O should exhibit a larger heat storage capacity. With respect to the reaction kinetics, the initial dehydration of Y2(SO4)3·8H2O to rhombohedral Y2(SO4)3 introduces a microStructure with pores on the micron order, which might enhance the reaction rate.

Francesco Petrini - One of the best experts on this subject based on the ideXlab platform.

  • wind induced vibration mitigation in tall buildings using the tuned mass damper inerter
    Journal of Structural Engineering-asce, 2017
    Co-Authors: Agathoklis Giaralis, Francesco Petrini
    Abstract:

    In this paper the classical linear tuned mass-damper (TMD) is coupled with an inerter, a two-terminal device resisting the relative acceleration of its terminals, in various tuned mass-damper-inerter (TMDI) topologies to suppress excessive wind-induced oscillations in tall buildings causing occupants’ discomfort. A parametric numerical study is undertaken involving a top-floor-TMD-equipped planar frame capturing accurately the in-plane dynamic behavior of a 74-storey benchmark building exposed to a quasi-stationary spatially-correlated wind-force field accounting for vortex shedding effects in the across-wind direction. It is found that the TMDI reduces the peak top floor acceleration more effectively than the TMD by considering smaller attached mass values, and TMDI topologies in which the inerter spans more stories in linking the attached mass to the Host Structure. Moreover, the inclusion of the inerter reduces dramatically the TMD stroke while it was verified that the magnitude of the developing inerter forces can be readily accommodated by the Host Structure. Pertinent illustrative examples are included showcasing that the TMDI meets code-prescribed serviceability design requirements for new tall buildings using significantly smaller attached mass compared to the TMD, and that inerter devices can be used to upgrade the performance of existing TMD-equipped tall buildings without changing the attached mass.

Kunihiko Shizume - One of the best experts on this subject based on the ideXlab platform.

  • multi step hydration dehydration mechanisms of rhombohedral y2 so4 3 a candidate material for low temperature thermochemical heat storage
    RSC Advances, 2020
    Co-Authors: Kunihiko Shizume, Naoyuki Hatada, Shoko Yasui, Tetsuya Uda
    Abstract:

    To evaluate rhombohedral Y2(SO4)3 as a new potential material for low-temperature thermochemical energy storage, its thermal behavior, phase changes, and hydration/dehydration reaction mechanisms are investigated. Rhombohedral Y2(SO4)3 exhibits reversible hydration/dehydration below 130 °C with relatively small thermal hysteresis (less than 50 °C). The reactions proceed via two reaction steps in approximately 0.02 atm of water vapor pressure, i.e. “high-temperature reaction” at 80–130 °C and “low-temperature reaction” at 30–100 °C. The high-temperature reaction proceeds by water insertion into the rhombohedral Y2(SO4)3 Host Structure to form rhombohedral Y2(SO4)3·xH2O (x = ∼1). For the low-temperature reaction, rhombohedral Y2(SO4)3·xH2O accommodates additional water molecules (x > 1) and is eventually hydrated to Y2(SO4)3·8H2O (monoclinic) with changes in the Host Structure. At a water vapor pressure above 0.08 atm, intermediate Y2(SO4)3·3H2O appears. A phase stability diagram of the hydrates is constructed and the potential usage of Y2(SO4)3 for thermal energy upgrades is assessed. The high-temperature reaction may act similarly to an existing candidate, CaSO4·0.5H2O, in terms of reaction temperature and water vapor pressure. Additionally, the hydration of rhombohedral Y2(SO4)3·xH2O to Y2(SO4)3·3H2O should exhibit a larger heat storage capacity. With respect to the reaction kinetics, the initial dehydration of Y2(SO4)3·8H2O to rhombohedral Y2(SO4)3 introduces a microStructure with pores on the micron order, which might enhance the reaction rate.

Agathoklis Giaralis - One of the best experts on this subject based on the ideXlab platform.

  • wind induced vibration mitigation in tall buildings using the tuned mass damper inerter
    Journal of Structural Engineering-asce, 2017
    Co-Authors: Agathoklis Giaralis, Francesco Petrini
    Abstract:

    In this paper the classical linear tuned mass-damper (TMD) is coupled with an inerter, a two-terminal device resisting the relative acceleration of its terminals, in various tuned mass-damper-inerter (TMDI) topologies to suppress excessive wind-induced oscillations in tall buildings causing occupants’ discomfort. A parametric numerical study is undertaken involving a top-floor-TMD-equipped planar frame capturing accurately the in-plane dynamic behavior of a 74-storey benchmark building exposed to a quasi-stationary spatially-correlated wind-force field accounting for vortex shedding effects in the across-wind direction. It is found that the TMDI reduces the peak top floor acceleration more effectively than the TMD by considering smaller attached mass values, and TMDI topologies in which the inerter spans more stories in linking the attached mass to the Host Structure. Moreover, the inclusion of the inerter reduces dramatically the TMD stroke while it was verified that the magnitude of the developing inerter forces can be readily accommodated by the Host Structure. Pertinent illustrative examples are included showcasing that the TMDI meets code-prescribed serviceability design requirements for new tall buildings using significantly smaller attached mass compared to the TMD, and that inerter devices can be used to upgrade the performance of existing TMD-equipped tall buildings without changing the attached mass.

Fukuo Chang - One of the best experts on this subject based on the ideXlab platform.

  • adhesive interface layer effects in pzt induced lamb wave propagation
    Smart Materials and Structures, 2010
    Co-Authors: Sungwon Ha, Fukuo Chang
    Abstract:

    In PZT-induced acousto-ultrasound techniques, the adhesive layer between a PZT and a Host Structure significantly affects sensor signals. However, its effects have been barely studied so far. A numerical model is essential to fundamentally understand the role of the adhesive interface. Using the hybrid spectral element, the effects of the adhesive bond-line layer on the Lamb wave generation and reception were modeled and compared with available test data for validation of the hybrid spectral element. The validations were conducted with different adhesive layer thicknesses. The trends in simulation results agreed well with the experiments. Parametric studies are presented to understand the adhesive layer effects. In these studies, adhesive thickness and stiffness, and PZT diameter and thickness, are selected as parameters. The physics of the adhesive layer are then discussed.