The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Roger Lewis - One of the best experts on this subject based on the ideXlab platform.

  • the low adhesion problem due to leaf contamination in the wheel rail Contact Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Abstract Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

  • The low adhesion problem due to leaf contamination in the wheel/rail Contact: Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

Kei Ishizaka - One of the best experts on this subject based on the ideXlab platform.

  • the low adhesion problem due to leaf contamination in the wheel rail Contact Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Abstract Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

  • The low adhesion problem due to leaf contamination in the wheel/rail Contact: Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

S.r. Lewis - One of the best experts on this subject based on the ideXlab platform.

  • the low adhesion problem due to leaf contamination in the wheel rail Contact Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Abstract Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

  • The low adhesion problem due to leaf contamination in the wheel/rail Contact: Bonding and low adhesion mechanisms
    Wear, 2017
    Co-Authors: Kei Ishizaka, S.r. Lewis, Roger Lewis
    Abstract:

    Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00–10:00 and 20:00–24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the Contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the Bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for Bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel.

A. La Magna - One of the best experts on this subject based on the ideXlab platform.

  • Role of Contact Bonding on electronic transport in metal-carbon nanotube-metal systems
    Nanotechnology, 2006
    Co-Authors: Ioannis Deretzis, A. La Magna
    Abstract:

    We have investigated the effects of the interfacial bond arrangement on the electronic transport features of metal-nanotube-metal systems. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to Au(111) metallic Contacts have been calculated by means of the non-equilibrium Green functional formalism with the Tight-Binding and the Extended Huckel Hamiltonians. Our calculations show that the electrode material is not the only factor which rules Contact transparency. Indeed, for the same electrode, but changing nanotube helicities, we have observed an overall complex behaviour of the transmission spectra due to band mixing and interference. The comparison of the two models shows that the Tight Binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C-C and Au-C chemical bonds has to be considered. We have furthermore examined the effect of interface geometry variance on conduction and found that Contact-nanotube distance has a significant impact, while Contact-nanotube symmetry plays a marginal, yet evident role.

  • role of Contact Bonding on electronic transport in metal carbon nanotube metal systems
    Nanotechnology, 2006
    Co-Authors: Ioannis Deretzis, A. La Magna
    Abstract:

    We have investigated the effects of the interfacial bond arrangement on the electronic transport features of metal–nanotube–metal systems. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to Au(111) metallic Contacts have been calculated by means of the non-equilibrium Green functional formalism with the tight-binding and the extended Huckel Hamiltonians. Our calculations show that the electrode material is not the only factor which rules Contact transparency. Indeed, for the same electrode, but changing nanotube helicities, we have observed an overall complex behaviour of the transmission spectra due to band mixing and interference. A comparison of the two models shows that the tight-binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C–C and Au–C chemical bonds has to be considered. We have furthermore examined the effect of interface geometry variance on conduction and found that the Contact–nanotube distance has a significant impact, while the Contact–nanotube symmetry plays a marginal, yet evident role.

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

  • Role of Contact Bonding on electronic transport in metal-carbon nanotube-metal systems
    Nanotechnology, 2006
    Co-Authors: Ioannis Deretzis, A. La Magna
    Abstract:

    We have investigated the effects of the interfacial bond arrangement on the electronic transport features of metal-nanotube-metal systems. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to Au(111) metallic Contacts have been calculated by means of the non-equilibrium Green functional formalism with the Tight-Binding and the Extended Huckel Hamiltonians. Our calculations show that the electrode material is not the only factor which rules Contact transparency. Indeed, for the same electrode, but changing nanotube helicities, we have observed an overall complex behaviour of the transmission spectra due to band mixing and interference. The comparison of the two models shows that the Tight Binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C-C and Au-C chemical bonds has to be considered. We have furthermore examined the effect of interface geometry variance on conduction and found that Contact-nanotube distance has a significant impact, while Contact-nanotube symmetry plays a marginal, yet evident role.

  • role of Contact Bonding on electronic transport in metal carbon nanotube metal systems
    Nanotechnology, 2006
    Co-Authors: Ioannis Deretzis, A. La Magna
    Abstract:

    We have investigated the effects of the interfacial bond arrangement on the electronic transport features of metal–nanotube–metal systems. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to Au(111) metallic Contacts have been calculated by means of the non-equilibrium Green functional formalism with the tight-binding and the extended Huckel Hamiltonians. Our calculations show that the electrode material is not the only factor which rules Contact transparency. Indeed, for the same electrode, but changing nanotube helicities, we have observed an overall complex behaviour of the transmission spectra due to band mixing and interference. A comparison of the two models shows that the tight-binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C–C and Au–C chemical bonds has to be considered. We have furthermore examined the effect of interface geometry variance on conduction and found that the Contact–nanotube distance has a significant impact, while the Contact–nanotube symmetry plays a marginal, yet evident role.