The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Abel Rousset - One of the best experts on this subject based on the ideXlab platform.

  • Zirconia-spinel composites. Part I: synthesis of powders and dense materials
    Materials Research Bulletin, 2000
    Co-Authors: Olivier Quénard, Christophe Laurent, Alain Peigney, Abel Rousset
    Abstract:

    International audienceMgAl2O4 and x wt% ZrO2-MgAl2O4 (1 # x # 30) composite powders were prepared by the urea combustion route. The powders were further ground by either ball milling or attrition to refine the Grain Size. Zirconia was found solely in the tetragonal form. Dense materials were prepared by hot pressing. The spinel Matrix Grains were submicronic in Size. The ZrO2 particles were homogeneously dispersed at the Grain junctions of the Matrix, and their average Size increased from less than 0.20 mm to ca. 0.45 mm with increasing content of ZrO2. The formation of monoclinic ZrO2 particles proceeded accordingly, being easier in materials with a finer Matrix Grain Size (ex-attrition)

  • Zirconia-spinel composites. Part I: synthesis of powders and dense materials
    Materials Research Bulletin, 2000
    Co-Authors: Olivier Quénard, Christophe Laurent, Alain Peigney, Abel Rousset
    Abstract:

    MgAl2O4 and x wt% ZrO2-MgAl2O4 (1 # x # 30) composite powders were prepared by the urea combustion route. The powders were further ground by either ball milling or attrition to refine the Grain Size. Zirconia was found solely in the tetragonal form. Dense materials were prepared by hot pressing. The spinel Matrix Grains were submicronic in Size. The ZrO2 particles were homogeneously dispersed at the Grain junctions of the Matrix, and their average Size increased from less than 0.20 mm to ca. 0.45 mm with increasing content of ZrO2. The formation of monoclinic ZrO2 particles proceeded accordingly, being easier in materials with a finer Matrix Grain Size (ex-attrition).

Kang Cheung Chan - One of the best experts on this subject based on the ideXlab platform.

  • deposition behaviour and morphology of ni sic electro composites under triangular waveform
    Applied Surface Science, 2005
    Co-Authors: Kang Cheung Chan
    Abstract:

    Abstract The deposition behaviour and morphology of Ni–SiC electro-composites were investigated under a triangular waveform. It was found that the Grain Size of the Ni–SiC composites decreased with increasing average current density, and the hardness of the composites increased with decreasing nickel Matrix Grain Size. An equivalent circuit model based on the results of electrochemical impedance spectroscopy was formulated to simulate the charge transfer process under triangular waveform. Compared with deposits produced under the direct current, the triangular waveform with relaxation time provided a higher instantaneous peak current for charge transfer, which resulted in an improvement in morphology and hardness of the composites. The mathematical model was found to be in agreement with the experimental results.

  • Deposition behaviour and morphology of Ni–SiC electro-composites under triangular waveform
    Applied Surface Science, 2005
    Co-Authors: Kang Cheung Chan
    Abstract:

    The deposition behaviour and morphology of Ni-SiC electro-composites were investigated under a triangular waveform. It was found that the Grain Size of the Ni-SiC composites decreased with increasing average current density, and the hardness of the composites increased with decreasing nickel Matrix Grain Size. An equivalent circuit model based on the results of electrochemical impedance spectroscopy was formulated to simulate the charge transfer process under triangular waveform. Compared with deposits produced under the direct current, the triangular waveform with relaxation time provided a higher instantaneous peak current for charge transfer, which resulted in an improvement in morphology and hardness of the composites. The mathematical model was found to be in agreement with the experimental results.Department of Industrial and Systems Engineerin

E Klumpp - One of the best experts on this subject based on the ideXlab platform.

  • bacteria transport and deposition under unsaturated conditions the role of the Matrix Grain Size and the bacteria surface protein
    Journal of Contaminant Hydrology, 2007
    Co-Authors: G Gargiulo, J Simůnek, P Ustohal, H Vereecken, Scott A Bradford, E Klumpp
    Abstract:

    Unsaturated (80% water saturated) packed column experiments were conducted to investigate the influence of Grain Size distribution and bacteria surface macromolecules on bacteria (Rhodococcus rhodochrous) transport and deposition mechanisms. Three Sizes of silica sands were used in these transport experiments, and their median Grain Sizes were 607, 567, and 330 μm. The amount of retained bacteria increased with decreasing sand Size, and most of the deposited bacteria were found adjacent to the column inlet. The deposition profiles were not consistent with predictions based on classical filtration theory. The experimental data could be accurately characterized using a mathematical model that accounted for first-order attachment, detachment, and time and depth-dependent straining processes. Visual observations of the bacteria deposition as well as mathematical modelling indicated that straining was the dominant mechanism of deposition in these sands (78–99.6% of the deposited bacteria), which may have been enhanced due to the tendency of this bacterium to form aggregates. An additional unsaturated experiment was conducted to better deduce the role of bacteria surface macromolecules on attachment and straining processes. In this case, the bacteria surface was treated using a proteolitic enzyme. This technique was assessed by examining the Fourier-transform infrared spectrum and hydrophobicity of untreated and enzyme treated cells. Both of these analytical procedures demonstrated that this enzymatic treatment removed the surface proteins and/or associated macromolecules. Transport and

  • Bacteria transport and deposition under unsaturated conditions: the role of the Matrix Grain Size and the bacteria surface protein.
    Journal of contaminant hydrology, 2007
    Co-Authors: G Gargiulo, S Bradford, J Simůnek, P Ustohal, H Vereecken, E Klumpp
    Abstract:

    Unsaturated (80% water saturated) packed column experiments were conducted to investigate the influence of Grain Size distribution and bacteria surface macromolecules on bacteria (Rhodococcus rhodochrous) transport and deposition mechanisms. Three Sizes of silica sands were used in these transport experiments, and their median Grain Sizes were 607, 567, and 330 microm. The amount of retained bacteria increased with decreasing sand Size, and most of the deposited bacteria were found adjacent to the column inlet. The deposition profiles were not consistent with predictions based on classical filtration theory. The experimental data could be accurately characterized using a mathematical model that accounted for first-order attachment, detachment, and time and depth-dependent straining processes. Visual observations of the bacteria deposition as well as mathematical modelling indicated that straining was the dominant mechanism of deposition in these sands (78-99.6% of the deposited bacteria), which may have been enhanced due to the tendency of this bacterium to form aggregates. An additional unsaturated experiment was conducted to better deduce the role of bacteria surface macromolecules on attachment and straining processes. In this case, the bacteria surface was treated using a proteolitic enzyme. This technique was assessed by examining the Fourier-transform infrared spectrum and hydrophobicity of untreated and enzyme treated cells. Both of these analytical procedures demonstrated that this enzymatic treatment removed the surface proteins and/or associated macromolecules. Transport and modelling studies conducted with the enzyme treated bacteria, revealed a decrease in attachment, but that straining was not significantly affected by this treatment.

Olivier Quénard - One of the best experts on this subject based on the ideXlab platform.

  • Zirconia-spinel composites. Part I: synthesis of powders and dense materials
    Materials Research Bulletin, 2000
    Co-Authors: Olivier Quénard, Christophe Laurent, Alain Peigney, Abel Rousset
    Abstract:

    International audienceMgAl2O4 and x wt% ZrO2-MgAl2O4 (1 # x # 30) composite powders were prepared by the urea combustion route. The powders were further ground by either ball milling or attrition to refine the Grain Size. Zirconia was found solely in the tetragonal form. Dense materials were prepared by hot pressing. The spinel Matrix Grains were submicronic in Size. The ZrO2 particles were homogeneously dispersed at the Grain junctions of the Matrix, and their average Size increased from less than 0.20 mm to ca. 0.45 mm with increasing content of ZrO2. The formation of monoclinic ZrO2 particles proceeded accordingly, being easier in materials with a finer Matrix Grain Size (ex-attrition)

  • Zirconia-spinel composites. Part I: synthesis of powders and dense materials
    Materials Research Bulletin, 2000
    Co-Authors: Olivier Quénard, Christophe Laurent, Alain Peigney, Abel Rousset
    Abstract:

    MgAl2O4 and x wt% ZrO2-MgAl2O4 (1 # x # 30) composite powders were prepared by the urea combustion route. The powders were further ground by either ball milling or attrition to refine the Grain Size. Zirconia was found solely in the tetragonal form. Dense materials were prepared by hot pressing. The spinel Matrix Grains were submicronic in Size. The ZrO2 particles were homogeneously dispersed at the Grain junctions of the Matrix, and their average Size increased from less than 0.20 mm to ca. 0.45 mm with increasing content of ZrO2. The formation of monoclinic ZrO2 particles proceeded accordingly, being easier in materials with a finer Matrix Grain Size (ex-attrition).

G Gargiulo - One of the best experts on this subject based on the ideXlab platform.

  • bacteria transport and deposition under unsaturated conditions the role of the Matrix Grain Size and the bacteria surface protein
    Journal of Contaminant Hydrology, 2007
    Co-Authors: G Gargiulo, J Simůnek, P Ustohal, H Vereecken, Scott A Bradford, E Klumpp
    Abstract:

    Unsaturated (80% water saturated) packed column experiments were conducted to investigate the influence of Grain Size distribution and bacteria surface macromolecules on bacteria (Rhodococcus rhodochrous) transport and deposition mechanisms. Three Sizes of silica sands were used in these transport experiments, and their median Grain Sizes were 607, 567, and 330 μm. The amount of retained bacteria increased with decreasing sand Size, and most of the deposited bacteria were found adjacent to the column inlet. The deposition profiles were not consistent with predictions based on classical filtration theory. The experimental data could be accurately characterized using a mathematical model that accounted for first-order attachment, detachment, and time and depth-dependent straining processes. Visual observations of the bacteria deposition as well as mathematical modelling indicated that straining was the dominant mechanism of deposition in these sands (78–99.6% of the deposited bacteria), which may have been enhanced due to the tendency of this bacterium to form aggregates. An additional unsaturated experiment was conducted to better deduce the role of bacteria surface macromolecules on attachment and straining processes. In this case, the bacteria surface was treated using a proteolitic enzyme. This technique was assessed by examining the Fourier-transform infrared spectrum and hydrophobicity of untreated and enzyme treated cells. Both of these analytical procedures demonstrated that this enzymatic treatment removed the surface proteins and/or associated macromolecules. Transport and

  • Bacteria transport and deposition under unsaturated conditions: the role of the Matrix Grain Size and the bacteria surface protein.
    Journal of contaminant hydrology, 2007
    Co-Authors: G Gargiulo, S Bradford, J Simůnek, P Ustohal, H Vereecken, E Klumpp
    Abstract:

    Unsaturated (80% water saturated) packed column experiments were conducted to investigate the influence of Grain Size distribution and bacteria surface macromolecules on bacteria (Rhodococcus rhodochrous) transport and deposition mechanisms. Three Sizes of silica sands were used in these transport experiments, and their median Grain Sizes were 607, 567, and 330 microm. The amount of retained bacteria increased with decreasing sand Size, and most of the deposited bacteria were found adjacent to the column inlet. The deposition profiles were not consistent with predictions based on classical filtration theory. The experimental data could be accurately characterized using a mathematical model that accounted for first-order attachment, detachment, and time and depth-dependent straining processes. Visual observations of the bacteria deposition as well as mathematical modelling indicated that straining was the dominant mechanism of deposition in these sands (78-99.6% of the deposited bacteria), which may have been enhanced due to the tendency of this bacterium to form aggregates. An additional unsaturated experiment was conducted to better deduce the role of bacteria surface macromolecules on attachment and straining processes. In this case, the bacteria surface was treated using a proteolitic enzyme. This technique was assessed by examining the Fourier-transform infrared spectrum and hydrophobicity of untreated and enzyme treated cells. Both of these analytical procedures demonstrated that this enzymatic treatment removed the surface proteins and/or associated macromolecules. Transport and modelling studies conducted with the enzyme treated bacteria, revealed a decrease in attachment, but that straining was not significantly affected by this treatment.