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Mohd Hamdi - One of the best experts on this subject based on the ideXlab platform.

  • A novel fabrication method for TiC–Al2O3–Fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.

  • a novel fabrication method for tic al2o3 fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.

Y. Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • Heat transfer to liquid and supercritical helium in superconducting rotors
    IEEE Transactions on Energy Conversion, 1992
    Co-Authors: R. Nakajima, K. Sato, K. Miyaike, M. Kumagai, Y. Kobayashi
    Abstract:

    Cooling designs of superconducting generator rotors are important for maintaining a stable superconducting state of field windings, and it is essential to comprehend the heat transfer characteristics of helium in rotating fields. Experiments were carried out using a large-scale rotating cryostat with a cold rotor diameter of approximately 800 mm. Clear differences among the steady-state heat transfer characteristics of helium were confirmed between low Centrifugal Acceleration fields and high Centrifugal Acceleration fields, resulting in the collection of heat transfer data under the supercritical state necessary for cooling designs. The heat transfer characteristics of liquid and supercritical helium under conditions of gravitational and Centrifugal Acceleration fields are discussed.

Mohsen A. Hassan - One of the best experts on this subject based on the ideXlab platform.

  • A novel fabrication method for TiC–Al2O3–Fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.

  • a novel fabrication method for tic al2o3 fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.

V. Prat - One of the best experts on this subject based on the ideXlab platform.

  • The traditional approximation of rotation, including the Centrifugal Acceleration for slightly deformed stars
    Astronomy and Astrophysics - A&A, 2019
    Co-Authors: S. Mathis, V. Prat
    Abstract:

    Context. The traditional approximation of rotation (TAR) is a treatment of the dynamical equations of rotating and stably stratified fluids in which the action of the Coriolis Acceleration along the direction of the entropy (and chemicals) stratification is neglected, while assuming that the fluid motions are mostly horizontal because of their inhibition in the vertical direction by the buoyancy force. This leads to the neglect of the horizontal projection of the rotation vector in the equations for the dynamics of gravito-inertial waves (GIWs) that become separable, such as in the non-rotating case, while they are not separable in the case in which the full Coriolis Acceleration is taken into account. This approximation, first introduced in geophysical fluid dynamics for thin atmospheres and oceans, has been broadly applied in stellar (and planetary) astrophysics to study low-frequency GIWs that have short vertical wavelengths. The appoximation is now being tested thanks to direct 2D oscillation codes, which constrain its domain of validity. The mathematical flexibility of this treatment allows us to explore broad parameter spaces and to perform detailed seismic modelling of stars.Aims. The TAR treatment is built on the assumptions that the star is spherical (i.e. its Centrifugal deformation is neglected) and uniformly rotating while an adiabatic treatment of the dynamics of the waves is adopted. In addition, their induced gravitational potential fluctuations is neglected. However, it has been recently generalised with including the effects of a differential rotation. We aim to carry out a new generalisation that takes into account the Centrifugal Acceleration in the case of deformed stars that are moderately and uniformly rotating.Methods. We construct an analytical expansion of the equations for the dynamics of GIWs in a spheroidal coordinates system by assuming the hierarchies of frequencies and amplitudes of the velocity components adopted within TAR in the spherical case.Results. We derive the complete set of equations that generalises TAR by taking the Centrifugal Acceleration into account. As in the case of a differentially rotating spherical star, the problem becomes 2D but can be treated analytically if we assume the anelastic and JWKB approximations, which are relevant for low-frequency GIWs. This allows us to derive a generalised Laplace tidal equation for the horizontal eigenfunctions and asymptotic wave periods, which can be used to probe the structure and dynamics of rotating deformed stars thanks to asteroseismology. A first numerical exploration of its eigenvalues and horizontal eigenfunctions shows their variation as a function of the pseudo-radius for different rotation rates and frequencies and the development of avoided crossings.

  • The traditional approximation of rotation, including the Centrifugal Acceleration for slightly deformed stars
    Astronomy and Astrophysics, 2019
    Co-Authors: S. Mathis, V. Prat
    Abstract:

    The Traditional Approximation of Rotation (TAR) is a treatment of the dynamical equations of rotating stably stratified fluids where the action of the Coriolis Acceleration along the direction of the entropy (and chemicals) stratification is neglected while assuming that the fluid motions are mostly horizontal because of their inhibition in the vertical direction by the buoyancy force. This leads to neglect the horizontal projection of the rotation vector in the equations for the dynamics of gravito-inertial waves (GIWs) that become separable as in the non-rotating case while they are not in the case with the full Coriolis Acceleration. This approximation has been broadly applied in stellar (and planetary) astrophysics to study low-frequency GIWs. TAR is built on the assumptions that the star is spherical (i.e. its Centrifugal deformation is neglected) and uniformly rotating while an adiabatic treatment of the dynamics of the waves is adopted. However, it has been recently generalised with including the effects of a differential rotation. We aim to do a new generalisation that takes into account the Centrifugal Acceleration in the case of moderately uniformly rotating deformed stars. As in the case of a differentially rotating spherical star, the problem becomes 2D but can be treated analytically if assuming the Cowling, anelastic and JWKB approximations, which are relevant for low-frequency GIWs. It allows us to derive a generalised Laplace tidal equation for the horizontal eigenfunctions and asymptotic wave periods that can be used to probe the structure and dynamics of rotating deformed stars thanks to asteroseismology. A first numerical exploration of its eigenvalues and horizontal eigenfunctions shows their variation as a function of the pseudo-radius for different rotation rates and frequencies and the development of avoided crossings.

Reza Mahmoodian - One of the best experts on this subject based on the ideXlab platform.

  • A novel fabrication method for TiC–Al2O3–Fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.

  • a novel fabrication method for tic al2o3 fe functional material under Centrifugal Acceleration
    Composites Part B-engineering, 2013
    Co-Authors: Reza Mahmoodian, Mohsen A. Hassan, R. G. Rahbari, Rosiyah Yahya, Mohd Hamdi
    Abstract:

    Abstract Compacted powders of titanium (Ti) and carbon (C) in form of pellets were exposed to a massive amount of heat generated from the thermite reaction of Fe2O3 and Al in a graphite–steel tube mounted in a developed Centrifugal accelerator machine. The Centrifugal force facilitated the formation of multi-component products during the process. Titanium carbide (TiC) product is joined to an Al2O3–Fe layer, which are the products of the thermite reaction. The existence of Centrifugal Acceleration had a significant effect on both metallurgical alloying and mechanical interlocking between different layers of the sample to form a functional material. A mathematical model developed for this experiment to describe the speed rate of iron infiltration inside the TiC product as well as viscosity rate variation was presented. The composition, microstructure and mechanical properties confirmed the model.