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

  • dissolved and particulate fe in a hydrothermal plume at 9 45 n east pacific rise slow fe ii oxidation kinetics in pacific plumes
    Geochimica et Cosmochimica Acta, 2000
    Co-Authors: Paul M Field, Robert M Sherrell
    Abstract:

    Production of Fe(III) particles in hydrothermal plumes is of fundamental importance to the long-term effect of hydrothermal circulation on seawater composition. To elucidate the fundamental controls on Fe redox kinetics and solution/particle partitioning in neutrally buoyant plumes, we sampled near-field (<3 km) plume particles at 9°45′N on the East Pacific Rise in 1996, returning in 1997 to sample both particulate and dissolved phases (0.40 μm filter). Concentrations of dissolved Fe varied from 320 to 20 nM in proximal (<0.3 km from Vent site) to distal samples (1–3 km downfield), constituting ∼85–50% of total Fe, respectively. Based on Vent fluid dilution factors calculated from dissolved Mn, a mass balance for Vent fluid Fe at this site indicates that ∼65% of Fe is lost to particulate sulfide settling in the buoyant plume, and that particulate Fe in distal (1–3 km) samples is twice as concentrated as predicted from dilution of particles in proximal plume water. These observations are consistent with a calculated Fe(II) oxidation half-time of 3.3 h, long enough that Fe(III) colloid production and aggregation occurs primarily in the neutrally buoyant plume at relatively high dilutions, preVenting generation of high particulate Fe concentrations (11–56 nM observed). A general investigation of Fe(II) oxidation rates in plumes worldwide gives Fe(II) oxidation half-lives as short as 17 min at some Atlantic sites, and as long as 6 h at some Pacific sites. The calculations indicate that the distribution of Fe particles in plumes depends chiefly on inter-basin differences in ambient deep water chemistry (primarily pH and dissolved O2) and on local currents driving plume dilution, and to a much lesser extent on variations in Primary Vent fluid composition. Long-term changes in thermohaline circulation or ocean biogeochemistry may therefore alter Fe dynamics and minor element fluxes associated with global hydrothermal activity, independent of variations in crustal production rates.

  • dissolved and particulate fe in a hydrothermal plume at 9 degree 45 minutes n east pacific rise slow fe ii oxidation kinetics in pacific plumes
    Geochimica et Cosmochimica Acta, 2000
    Co-Authors: M P Field, Robert M Sherrell
    Abstract:

    Production of Fe(III) particles in hydrothermal plumes is of fundamental importance to the long-term effect of hydrothermal circulation on seawater composition. To elucidate the fundamental controls on Fe redox kinetics and solution/particle partitioning in neutrally buoyant plumes, the authors sampled near-field (<3 km) plume particles at 9{degree}45 minutes N on the East Pacific Rise in 1996, returning in 1997 to sample both particulate and dissolved phases (0.40 {micro}m filter). Concentrations of dissolved Fe varied from 320 to 20 nM in proximal (<0.3 km from Vent site) to distal samples (1--3 km downfield), constituting {approximately}85--50% of total Fe, respectively. Based on Vent fluid dilution factors calculated from dissolved Mn, a mass balance for Vent fluid Fe at this site indicates that {approximately}65% of Fe is lost to particulate sulfide settling in the buoyant plume, and that particulate Fe in distal (1--3 km) samples is twice as concentrated as predicted from dilution of particles in proximal plume water. These observations are consistent with a calculated Fe(II) oxidation half-time of 3.3 h, long enough that Fe(III) colloid production and aggregation occurs primarily in the neutrally buoyant plume at relatively high dilutions, preVenting generation of high particular Fe concentrations (11--56 nM observed). A general more » investigation of Fe(II) oxidation rates in plumes worldwide gives Fe(II) oxidation half-lives as short as 17 min at some Atlantic sites, and as long as 6 h at some Pacific sites. The calculations indicate that the distribution of Fe particles in plumes depends chiefly on inter-basin differences in ambient deep water chemistry (primarily pH and dissolved O{sub 2}) and on local currents driving plume dilution, and to a much lesser extent on variations in Primary Vent fluid composition. Long-term changes in thermohaline circulation or ocean biogeochemistry may therefore alter Fe dynamics and minor element fluxes associated with global hydrothermal activity, independent of variations in crustal production rates. « less

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

  • dissolved and particulate fe in a hydrothermal plume at 9 45 n east pacific rise slow fe ii oxidation kinetics in pacific plumes
    Geochimica et Cosmochimica Acta, 2000
    Co-Authors: Paul M Field, Robert M Sherrell
    Abstract:

    Production of Fe(III) particles in hydrothermal plumes is of fundamental importance to the long-term effect of hydrothermal circulation on seawater composition. To elucidate the fundamental controls on Fe redox kinetics and solution/particle partitioning in neutrally buoyant plumes, we sampled near-field (<3 km) plume particles at 9°45′N on the East Pacific Rise in 1996, returning in 1997 to sample both particulate and dissolved phases (0.40 μm filter). Concentrations of dissolved Fe varied from 320 to 20 nM in proximal (<0.3 km from Vent site) to distal samples (1–3 km downfield), constituting ∼85–50% of total Fe, respectively. Based on Vent fluid dilution factors calculated from dissolved Mn, a mass balance for Vent fluid Fe at this site indicates that ∼65% of Fe is lost to particulate sulfide settling in the buoyant plume, and that particulate Fe in distal (1–3 km) samples is twice as concentrated as predicted from dilution of particles in proximal plume water. These observations are consistent with a calculated Fe(II) oxidation half-time of 3.3 h, long enough that Fe(III) colloid production and aggregation occurs primarily in the neutrally buoyant plume at relatively high dilutions, preVenting generation of high particulate Fe concentrations (11–56 nM observed). A general investigation of Fe(II) oxidation rates in plumes worldwide gives Fe(II) oxidation half-lives as short as 17 min at some Atlantic sites, and as long as 6 h at some Pacific sites. The calculations indicate that the distribution of Fe particles in plumes depends chiefly on inter-basin differences in ambient deep water chemistry (primarily pH and dissolved O2) and on local currents driving plume dilution, and to a much lesser extent on variations in Primary Vent fluid composition. Long-term changes in thermohaline circulation or ocean biogeochemistry may therefore alter Fe dynamics and minor element fluxes associated with global hydrothermal activity, independent of variations in crustal production rates.

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

  • dissolved and particulate fe in a hydrothermal plume at 9 degree 45 minutes n east pacific rise slow fe ii oxidation kinetics in pacific plumes
    Geochimica et Cosmochimica Acta, 2000
    Co-Authors: M P Field, Robert M Sherrell
    Abstract:

    Production of Fe(III) particles in hydrothermal plumes is of fundamental importance to the long-term effect of hydrothermal circulation on seawater composition. To elucidate the fundamental controls on Fe redox kinetics and solution/particle partitioning in neutrally buoyant plumes, the authors sampled near-field (<3 km) plume particles at 9{degree}45 minutes N on the East Pacific Rise in 1996, returning in 1997 to sample both particulate and dissolved phases (0.40 {micro}m filter). Concentrations of dissolved Fe varied from 320 to 20 nM in proximal (<0.3 km from Vent site) to distal samples (1--3 km downfield), constituting {approximately}85--50% of total Fe, respectively. Based on Vent fluid dilution factors calculated from dissolved Mn, a mass balance for Vent fluid Fe at this site indicates that {approximately}65% of Fe is lost to particulate sulfide settling in the buoyant plume, and that particulate Fe in distal (1--3 km) samples is twice as concentrated as predicted from dilution of particles in proximal plume water. These observations are consistent with a calculated Fe(II) oxidation half-time of 3.3 h, long enough that Fe(III) colloid production and aggregation occurs primarily in the neutrally buoyant plume at relatively high dilutions, preVenting generation of high particular Fe concentrations (11--56 nM observed). A general more » investigation of Fe(II) oxidation rates in plumes worldwide gives Fe(II) oxidation half-lives as short as 17 min at some Atlantic sites, and as long as 6 h at some Pacific sites. The calculations indicate that the distribution of Fe particles in plumes depends chiefly on inter-basin differences in ambient deep water chemistry (primarily pH and dissolved O{sub 2}) and on local currents driving plume dilution, and to a much lesser extent on variations in Primary Vent fluid composition. Long-term changes in thermohaline circulation or ocean biogeochemistry may therefore alter Fe dynamics and minor element fluxes associated with global hydrothermal activity, independent of variations in crustal production rates. « less

Mccraw Jim - One of the best experts on this subject based on the ideXlab platform.

  • Examination of Methods of Dry Gas Seal Supply, Regulation, and Monitoring
    Turbomachinery Laboratory Texas A&M Engineering Experiment Station, 2018
    Co-Authors: Akalchuk Vladimi, Dwye Kevi, Hosanna Rich, Chinnaswamy Sreenivasulu, Eisenmann, Jr. Robe, Mccraw Jim
    Abstract:

    TutorialsCompressor Dry Gas Seal Failure is a common issue that affects Turbomachinery train availability. Since most turbomachinery trains are un-spared critical assets, unscheduled shutdowns have a major impact to the operating facility. As operators look to extend equipment run time, the quality and delivery of the Primary seal gas supplied to the dry gas seal is vital to the long term operation. In case of a failure, automated trips can be applied to mitigate catastrophic failures but in many cases the machinery engineer needs to make an operations decision due to changing seal performance and needs to answer the following questions: • Is gas delivered to the seal at required volume and quality at all operating conditions? • How is the seal monitored? • What is the data telling me? • What is causing the abnormal indication? • What action should be taken? This tutorial examines the two main philosophies for delivering seal gas, comparing them with two calculated examples before describing a recommend Primary Vent monitoring setup and the associated instrumentation. The tutorial concludes with several examples based off real world failures to further illustrate the monitoring and diagnostic abilities of the dry gas seal system

Akalchuk Vladimi - One of the best experts on this subject based on the ideXlab platform.

  • Examination of Methods of Dry Gas Seal Supply, Regulation, and Monitoring
    Turbomachinery Laboratory Texas A&M Engineering Experiment Station, 2018
    Co-Authors: Akalchuk Vladimi, Dwye Kevi, Hosanna Rich, Chinnaswamy Sreenivasulu, Eisenmann, Jr. Robe, Mccraw Jim
    Abstract:

    TutorialsCompressor Dry Gas Seal Failure is a common issue that affects Turbomachinery train availability. Since most turbomachinery trains are un-spared critical assets, unscheduled shutdowns have a major impact to the operating facility. As operators look to extend equipment run time, the quality and delivery of the Primary seal gas supplied to the dry gas seal is vital to the long term operation. In case of a failure, automated trips can be applied to mitigate catastrophic failures but in many cases the machinery engineer needs to make an operations decision due to changing seal performance and needs to answer the following questions: • Is gas delivered to the seal at required volume and quality at all operating conditions? • How is the seal monitored? • What is the data telling me? • What is causing the abnormal indication? • What action should be taken? This tutorial examines the two main philosophies for delivering seal gas, comparing them with two calculated examples before describing a recommend Primary Vent monitoring setup and the associated instrumentation. The tutorial concludes with several examples based off real world failures to further illustrate the monitoring and diagnostic abilities of the dry gas seal system