The Experts below are selected from a list of 14781 Experts worldwide ranked by ideXlab platform

Alan W. Gertler - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of the effectiveness of control measures to mitigate road dust emissions in a regional network
    Transportation Research Part D: Transport and Environment, 2012
    Co-Authors: Dongzi Zhu, Hampden Kuhns, John A. Gillies, Vicken Etyemezian, Scott C. Brown, Alan W. Gertler
    Abstract:

    Abstract The effectiveness of control measures to reduce road dust emissions is analyzed using a year’s data of road dust emissions collected with a mobile sampling platform and a survey of road maintenance practices in the Lake Tahoe Basin of Nevada and California US. Attributes such as sweeping practices, anti-icing, shoulder improvement, pavement condition, trackout, and Abrasive Material from road segments were analyzed with a feature subset selection algorithm. Street sweeping was found to be an effective means of controlling dust emissions from roads. Road dust from dirty tertiary roads served as a continuous source of suspendable Material for adjacent high-speed roads in the winter time. To be most effective, emission control strategies require that not only primary roads, but all roads be swept after snow storms to recover applied Abrasive Material.

Vyacheslav Ya. Rodak - One of the best experts on this subject based on the ideXlab platform.

K. Osseo-asare - One of the best experts on this subject based on the ideXlab platform.

  • Surface Chemical Processes in Chemical Mechanical Polishing Relationship Between Silica Material Removal Rate and the Point of Zero Charge of the Abrasive Material
    Journal of The Electrochemical Society, 2002
    Co-Authors: K. Osseo-asare
    Abstract:

    Chemical mechanical polishing (CMP) of a silica substrate Is visualized as a two-step process involving release of substrate-derived species into solution (dissolution), followed by adsorption of these species by Abrasive particles. The adsorption is quantified by treating it as a surface complexation process. Mass action equations are provided for the complex-formation reaction as well as protonation and deprotonation of surface hydroxyls present on the Abrasive particles. By combining these equations with mass balances on surface sites and dissolved species, it is shown that the surface concentration of substrate-derived species (and, therefore, the Material removal rate) goes through a maximum as the point of zero charge (pzc) of the Abrasive particle increases. Further, it is shown that the surface concentration of substrate-derived species (and, therefore, the Material removal rate) is highest for the Abrasive Material whose pzc coincides with the pH of the polishing slurry.

A.p.m. Baptista - One of the best experts on this subject based on the ideXlab platform.

  • Role of Abrasive Material on micro­abrasion wear tests
    Wear, 2011
    Co-Authors: Francisco J. G. Silva, R. B. Casais, R. P. Martinho, A.p.m. Baptista
    Abstract:

    a b s t r a c t Micro­abrasion wear tests with ball­cratering configuration are widely used. Sources of variability are already studied by different authors and conditions for testing are parameterized by BS EN 1071­6: 2007 standard which refers silicon carbide as Abrasive. However, the use of other Abrasives is possible and allowed. In this work, ball­cratering wear tests were performed using four different Abrasive particles of three dissimilar Materials: diamond, alumina and silicon carbide. Tests were carried out under the same conditions on a steel plate provided with TiB2 hard coating. For each Abrasive, five different test durations were used allowing understanding the initial wear phenomena. Composition and shape of Abrasive parti­ cles were investigated by SEM and EDS. Scar areas were observed by optical and electronic microscopy in order to understand the wear effects caused by each of them. Scar geometry and grooves were analyzed and compared. Wear coefficient was calculated for each situation. It was observed that diamond parti­ cles produce well­defined and circular wear scars. Different silicon carbide particles presented dissimilar results as consequence of distinct particle shape and size distribution.

  • Role of Abrasive Material on micro-abrasion wear tests
    Wear, 2011
    Co-Authors: Francisco J. G. Silva, R. B. Casais, R. P. Martinho, A.p.m. Baptista
    Abstract:

    Micro-abrasion wear tests with ball-cratering configuration are widely used. Sources of variability are already studied by different authors and conditions for testing are parameterized by BS EN 1071-6: 2007 standard which refers silicon carbide as Abrasive. However, the use of other Abrasives is possible and allowed. In this work, ball-cratering wear tests were performed using four different Abrasive particles of three dissimilar Materials: diamond, alumina and silicon carbide. Tests were carried out under the same conditions on a steel plate provided with TiB2 hard coating. For each Abrasive, five different test durations were used allowing understanding the initial wear phenomena. Composition and shape of Abrasive particles were investigated by SEM and EDS. Scar areas were observed by optical and electronic microscopy in order to understand the wear effects caused by each of them. Scar geometry and grooves were analyzed and compared. Wear coefficient was calculated for each situation. It was observed that diamond particles produce well-defined and circular wear scars. Different silicon carbide particles presented dissimilar results as consequence of distinct particle shape and size distribution

Dongzi Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of the effectiveness of control measures to mitigate road dust emissions in a regional network
    Transportation Research Part D: Transport and Environment, 2012
    Co-Authors: Dongzi Zhu, Hampden Kuhns, John A. Gillies, Vicken Etyemezian, Scott C. Brown, Alan W. Gertler
    Abstract:

    Abstract The effectiveness of control measures to reduce road dust emissions is analyzed using a year’s data of road dust emissions collected with a mobile sampling platform and a survey of road maintenance practices in the Lake Tahoe Basin of Nevada and California US. Attributes such as sweeping practices, anti-icing, shoulder improvement, pavement condition, trackout, and Abrasive Material from road segments were analyzed with a feature subset selection algorithm. Street sweeping was found to be an effective means of controlling dust emissions from roads. Road dust from dirty tertiary roads served as a continuous source of suspendable Material for adjacent high-speed roads in the winter time. To be most effective, emission control strategies require that not only primary roads, but all roads be swept after snow storms to recover applied Abrasive Material.