The Experts below are selected from a list of 20154 Experts worldwide ranked by ideXlab platform

M. Braccini - One of the best experts on this subject based on the ideXlab platform.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 °C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate β-(Ni,Pt)Al bondcoat or a newly developed Zr-doped β-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 A degrees C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate beta-(Ni,Pt)Al bondcoat or a newly developed Zr-doped beta-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

P.-y. Théry - One of the best experts on this subject based on the ideXlab platform.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 °C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate β-(Ni,Pt)Al bondcoat or a newly developed Zr-doped β-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 A degrees C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate beta-(Ni,Pt)Al bondcoat or a newly developed Zr-doped beta-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

M. Dupeux - One of the best experts on this subject based on the ideXlab platform.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 °C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate β-(Ni,Pt)Al bondcoat or a newly developed Zr-doped β-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 A degrees C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate beta-(Ni,Pt)Al bondcoat or a newly developed Zr-doped beta-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

M. Poulain - One of the best experts on this subject based on the ideXlab platform.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 °C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate β-(Ni,Pt)Al bondcoat or a newly developed Zr-doped β-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

  • Spallation of two thermal barrier coating systems: experimental study of adhesion and energetic approach to Lifetime during cyclic oxidation
    Journal of Materials Science, 2009
    Co-Authors: P.-y. Théry, M. Poulain, M. Dupeux, M. Braccini
    Abstract:

    To understand the degradation of two thermal barrier coating (TBC) systems, we determined the adhesion energy between the bondcoat and the topcoat and its evolution during cyclic oxidation at 1,100 A degrees C, by means of a modified 4-point bending test. An yttria stabilized zirconia (YSZ) ceramic topcoat was deposited by electron beam physical vapour deposition (EBPVD) on a Ni-based superalloy with either an intermediate beta-(Ni,Pt)Al bondcoat or a newly developed Zr-doped beta-NiAl bondcoat. Although a similar evolution of the adhesion energy during cyclic oxidation has been recorded for both systems, observations of the fracture surfaces combined with a microstructure study revealed different degradation mechanisms. An energetic model of spallation is applied to predict their Lifetime. According to this approach, the TBC failure is induced by the accumulation of strain energy in the ceramic layers and resisted by the interfacial fracture toughness. The Predicted Lifetime is consistent with experiments for both systems.

Ioannis Ch. Paschalidis - One of the best experts on this subject based on the ideXlab platform.

  • Robust Maximum Lifetime Routing and Energy Allocation in Wireless Sensor Networks
    International Journal of Distributed Sensor Networks, 2012
    Co-Authors: Ioannis Ch. Paschalidis
    Abstract:

    We consider the maximum Lifetime routing problem in wireless sensor networks in two settings: (a) when nodes’ initial energy is given and (b) when it is subject to optimization. The optimal solution and objective value provide optimal flows and the corresponding Predicted Lifetime, respectively. We stipulate that there is uncertainty in various network parameters (available energy and energy depletion rates). In setting (a) we show that for specific, yet typical, network topologies, the actual network Lifetime will reach the Predicted value with a probability that converges to zero as the number of nodes grows large. In setting (b) the same result holds for all topologies. We develop a series of robust problem formulations, ranging from pessimistic to optimistic. A set of parameters enable the tuning of the conservatism of the formulation to obtain network flows with a desirably high probability that the corresponding Lifetime prediction is achieved. We establish a number of properties for the robust network flows and energy allocations and provide numerical results to highlight the tradeoff between Predicted Lifetime and the probability achieved. Further, we analyze an interesting limiting regime of massively deployed sensor networks and essentially solve a continuous version of the problem.

  • CDC - On robust maximum Lifetime routing in wireless sensor networks
    2008 47th IEEE Conference on Decision and Control, 2008
    Co-Authors: Ioannis Ch. Paschalidis
    Abstract:

    We consider the maximum Lifetime routing problem in wireless sensor networks, which has been formulated as a linear programming problem in the literature (Chang and Tassiulas [1]). The optimal value and optimal solution of this problem provide optimal flows for the network and the corresponding Predicted Lifetime, respectively. We study the situation when there is uncertainty in various network parameters (available energy and energy depletion rates). We show that for specific, yet typical, network topologies the actual Lifetime will reach the Predicted value with a probability that converges to zero as the number of nodes grows large. We develop a series of alternative robust problem formulations, ranging from worst-case to optimistic. A set of parameters enable the tuning of the conservatism of the formulation to obtain network flows with a desirably high probability that the corresponding Lifetime prediction will be achieved. We establish a number of properties for the robust network flows and provide an illustrative set of numerical results to highlight the trade-off between Predicted Lifetime and the probability it is achieved.