The Experts below are selected from a list of 5772 Experts worldwide ranked by ideXlab platform

Wontae Kim - One of the best experts on this subject based on the ideXlab platform.

Edwin J. Son - One of the best experts on this subject based on the ideXlab platform.

Shinji Mukohyama - One of the best experts on this subject based on the ideXlab platform.

  • Is the Brick-Wall model unstable for a rotating background?
    Physical Review D, 2000
    Co-Authors: Shinji Mukohyama
    Abstract:

    The stability of the Brick-Wall model is analyzed in a rotating background. It is shown that, in the Kerr background without an horizon but with an inner boundary, a scalar field has complex-frequency modes and that, however, the imaginary part of the complex frequency can be small enough compared with the Hawking temperature if the inner boundary is sufficiently close to the horizon, say at a proper altitude of Planck scale. Hence the time scale of the instability due to the complex frequencies is much longer than the relaxation time scale of the thermal state with the Hawking temperature. Since ambient fields should settle in the thermal state in the latter time scale, the instability is not so catastrophic. Thus the Brick-Wall model is well defined even in a rotating background if the inner boundary is sufficiently close to the horizon.

  • Entanglement/Brick-Wall entropies correspondence
    arXiv: General Relativity and Quantum Cosmology, 1999
    Co-Authors: Shinji Mukohyama
    Abstract:

    There have been many attempts to understand the statistical origin of black-hole entropy. Among them, entanglement entropy and the Brick Wall model are strong candidates. In this paper we show a relation between entanglement entropy and the Brick Wall model: the Brick Wall model seeks the maximal value of the entanglement entropy. In other words, the entanglement approach reduces to the Brick Wall model when we seek the maximal entanglement entropy .

  • Entanglement/Brick-Wall entropy’s correspondence
    Eighth Canadian conference on general relativity and relativistic astrophysics, 1999
    Co-Authors: Shinji Mukohyama
    Abstract:

    There have been many attempts to understand the statistical origin of black-hole entropy. Among them, entanglement entropy and the Brick Wall model are strong candidates. In this paper we show a relation between entanglement entropy and the Brick Wall model: the Brick Wall model seeks the maximal value of the entanglement entropy. In other words, the entanglement approach reduces to the Brick Wall model when we seek the maximal entanglement entropy.

  • Black holes, Brick Walls, and the Boulware state
    Physical Review D, 1998
    Co-Authors: Shinji Mukohyama, Werner Israel
    Abstract:

    The Brick-Wall model seeks to explain the Bekenstein-Hawking entropy as a Wall-contribution to the thermal energy of ambient quantum fields raised to the Hawking temperature. Reservations have been expressed concerning the self-consistency of this model. For example, it predicts large thermal energy densities near the Wall, producing a substantial mass-correction and, presumably, a large gravitational back-reaction. We re-examine this model and conclude that these reservations are unfounded once the ground state---the Boulware state---is correctly identified. We argue that the Brick-Wall model and the Gibbons-Hawking instanton (which ascribes a topological origin to the Bekenstein-Hawking entropy) are mutually exclusive, alternative descriptions (complementary in the sense of Bohr) of the same physics.

Marcel Lacroix - One of the best experts on this subject based on the ideXlab platform.

  • Inverse heat transfer prediction of the state of the Brick Wall of a melting furnace
    Applied Thermal Engineering, 2017
    Co-Authors: Mohamed Hafid, Marcel Lacroix
    Abstract:

    Abstract An inverse heat transfer method for predicting the state of the lateral refractory Brick Wall of a melting furnace is presented. By collecting temperature data with a thermocouple embedded into the Brick Wall, the inverse method is able to predict (1) the time-varying thickness of the protective bank that covers the inner lining of the furnace Wall; (2) the thermal contact resistance between the inner lining and the protective bank; and (3) the possible erosion of the refractory Brick Wall. The inverse procedure rests on the Levenberg Marquardt algorithm combined with the Broyden method. The effect (1) of the noise on the collected temperature data; (2) of the thermal diffusivity of the Brick Wall; (3) of the location of the embedded temperature sensor; and (4) of the Biot number on the inverse predictions is investigated. Recommendations are made for the optimum position of the embedded sensor and its operation.

  • An inverse heat transfer method for predicting the thermal characteristics of a molten material reactor
    Applied Thermal Engineering, 2016
    Co-Authors: Mohamed Hafid, Marcel Lacroix
    Abstract:

    Abstract An inverse heat transfer procedure is presented for predicting the time-varying thickness of the protective bank that covers the lining of the refractory Brick Walls of a molten material reactor. The inverse method predicts simultaneously influential thermo-physical properties of the reactor such as the thermal conductivity of the refractory Brick Wall, the thermal conductivity of the solid and of the liquid layers of the phase change material, and the time-varying reactor heat load. The inverse method rests on the Levenberg-Marquardt Method (LMM) combined with the Broyden method (BM). The effect (1) of the initial guesses for the unknown LMM polynomial parameters, (2) of the noise on the recorded temperature data, (3) of the location of the temperature sensors embedded into the Brick Wall and (4) of the number of recorded temperature data on the inverse predictions is investigated. Recommendations are then made concerning the installation and the operation of the temperature sensors.

Myungseok Yoon - One of the best experts on this subject based on the ideXlab platform.