The Experts below are selected from a list of 34479 Experts worldwide ranked by ideXlab platform

J. Kumpulainen - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of a wheat flour reference Material (Arc/CL) for twelve elements
    Fresenius' Journal of Analytical Chemistry, 1993
    Co-Authors: R. Tahvonen, J. Kumpulainen
    Abstract:

    An Arc/CL coded wheat flour reference Material (Arc/CL RM) with established recommended concentration values for 12 elements [1,2] was further characterized for P, K and Cr contents by means of an intercomparison study. Minor corrections were made to earlier recommended values in accordance with new results obtained. Fifteen laboratories using a total of 11 methods based on six entirely different analytical principles participated in the intercomparison study. The medians and standard deviations were calculated for the results of the intercomparison study. After rejecting as outliers values falling outside the median ± sd, the present recommended values were obtained by recalculating the median and 95% confidence limits. Recommended values were established for the major elements Ca, K, Mg, P, the minor elements Cu, Fe, Mn, Zn, and the trace elements Mo, Cr, Ni and Se. The relative standard deviations for the 95% confidence limits of the medians were lower than 10% for major and minor elements, 11% for Mo and 18% for Cr. All of the recommended concentration values fell into category A, having a high degree of confidence. The present RM, with its 16 recommended concentrations, is of value for use in nutritional, food composition and contaminant monitoring studies.

R. Tahvonen - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of a wheat flour reference Material (Arc/CL) for twelve elements
    Fresenius' Journal of Analytical Chemistry, 1993
    Co-Authors: R. Tahvonen, J. Kumpulainen
    Abstract:

    An Arc/CL coded wheat flour reference Material (Arc/CL RM) with established recommended concentration values for 12 elements [1,2] was further characterized for P, K and Cr contents by means of an intercomparison study. Minor corrections were made to earlier recommended values in accordance with new results obtained. Fifteen laboratories using a total of 11 methods based on six entirely different analytical principles participated in the intercomparison study. The medians and standard deviations were calculated for the results of the intercomparison study. After rejecting as outliers values falling outside the median ± sd, the present recommended values were obtained by recalculating the median and 95% confidence limits. Recommended values were established for the major elements Ca, K, Mg, P, the minor elements Cu, Fe, Mn, Zn, and the trace elements Mo, Cr, Ni and Se. The relative standard deviations for the 95% confidence limits of the medians were lower than 10% for major and minor elements, 11% for Mo and 18% for Cr. All of the recommended concentration values fell into category A, having a high degree of confidence. The present RM, with its 16 recommended concentrations, is of value for use in nutritional, food composition and contaminant monitoring studies.

Pravansu S Mohanty - One of the best experts on this subject based on the ideXlab platform.

  • High-speed visualization and plume characterization of the hybrid spray process
    Journal of Thermal Spray Technology, 2006
    Co-Authors: Jelena Stanišić, D. Kosikowski, Pravansu S Mohanty
    Abstract:

    The hybrid spray process that combines Arc spray with a high-velocity oxyfuel (HVOF)/plasma jet has recently demonstrated its effectiveness in deposition of functionally gradient coatings. This approach aims at exploiting the combined attributes of the Arc-spray technique and the HVOF/air plasma spraying (APS) technique. This paper presents high-speed visualization and plume characterization of an Arc/HVOF hybrid spray gun as well as a twin-wire Arc-spray gun. The physics of atomization in the hybrid spray process is examined using a high-speed camera. A DPV/CPS-2000 (Tecnar, St-Bruno, QC, Canada) particle diagnostics sensor is used to measure particle velocity, temperature, size, and distribution. The influence of feed Material, Arc parameters, and HVOF parameters on the particle characteristics is presented. Differences in the in-flight characteristics between the hybrid and the twin-wire Arc process are discussed aided by the observed atomization phenomena with the high-speed camera

Frédéric Pons - One of the best experts on this subject based on the ideXlab platform.

  • Electrical contact Material Arc erosion : experiments and modeling towards the design of an AgCdO substitute
    2010
    Co-Authors: Frédéric Pons
    Abstract:

    AgCdO is one of the most widely used contact Materials in the world because of its outstanding performance. Nevertheless, due to environmental considerations, it will soon be completely forbidden by European environmental directives. Therefore, finding a good substitute is of crucial importance. Electrical Arc erosion plays a crucial role in the reliability and life of power switching devices. Depending on the contact Material's behavior in response to an electrical Arc, surface damage can induce severe changes in contact Material properties that will impact the power switching device's functioning. Consequently, electrical Arc effects and consequences on the contact Material surface are of first importance. In this context, we have focused our reseArch activities on the following axes. First of all, in order to better understand AgCdO (Current contact Material in aerospace industry) and AgSnO2 (Potential candidate to AgCdO substitution) Arc erosion behaviors, Arc erosion experiments, where the power switching devices have been subjected to different numbers of Arc discharges, have been realized. Further, a general macroscopic electrical contact Arc erosion model valid for low and high currents was developed. To compare model results to experimental data, this model describes the complete breaking process of electrical contacts and gives the total amount of Material removed after one breaking operation. In parallel, Arc erosion experiments on AgCdO power switching devices have been conducted at high currents (0 -> 1000 A) in order to validate the Arc erosion model. Next, using the general Arc erosion model, the properties having the greatest influence on the electrical Arc erosion process have been determined through simulations on silver contact Material. At this stage, ab initio calculations were needed to obtain ranges of variation of certain silver contact Material properties. Finally, an investigation of the trends of changing local contact Material composition of AgSnO2 on these identified Material properties was performed. This study was based on ab initio calculations for two different oxide compositions of AgSnO2. These will allow us to give directions to aid the design of a good substitute for AgCdO, and therefore, to complete the main objective of this reseArch work

Jelena Stanišić - One of the best experts on this subject based on the ideXlab platform.

  • High-speed visualization and plume characterization of the hybrid spray process
    Journal of Thermal Spray Technology, 2006
    Co-Authors: Jelena Stanišić, D. Kosikowski, Pravansu S Mohanty
    Abstract:

    The hybrid spray process that combines Arc spray with a high-velocity oxyfuel (HVOF)/plasma jet has recently demonstrated its effectiveness in deposition of functionally gradient coatings. This approach aims at exploiting the combined attributes of the Arc-spray technique and the HVOF/air plasma spraying (APS) technique. This paper presents high-speed visualization and plume characterization of an Arc/HVOF hybrid spray gun as well as a twin-wire Arc-spray gun. The physics of atomization in the hybrid spray process is examined using a high-speed camera. A DPV/CPS-2000 (Tecnar, St-Bruno, QC, Canada) particle diagnostics sensor is used to measure particle velocity, temperature, size, and distribution. The influence of feed Material, Arc parameters, and HVOF parameters on the particle characteristics is presented. Differences in the in-flight characteristics between the hybrid and the twin-wire Arc process are discussed aided by the observed atomization phenomena with the high-speed camera