The Experts below are selected from a list of 13242 Experts worldwide ranked by ideXlab platform

Petra S. Dittrich - One of the best experts on this subject based on the ideXlab platform.

  • A microfluidic device for open loop stripping of volatile organic compounds
    Analytical and Bioanalytical Chemistry, 2013
    Co-Authors: Benjamin Z. Cvetković, Petra S. Dittrich
    Abstract:

    The detection of volatile organic compounds is of great importance for assessing the quality of water. In this contribution, we describe a miniaturized stripping device that allows fast online detection of organic solvents in water. The core component is a glass microfluidic chip that facilitates the creation of an annular-flowing stream of water and nitrogen gas. Volatile compounds are transferred efficiently from the water into the gas phase along the microfluidic pathway at room temperature within less than 5 s. Before exiting the microchip, the liquid phase is separated from the enriched gas phase by incorporating side capillaries through which the hydrophilic water phase is withdrawn. The gas phase is conveniently collected at the outlet reservoir by tubing. Finally, a semiconductor gas sensor analyzes the concentration of (volatile) organic compounds in the nitrogen gas. The operation and use of the stripping device is demonstrated for the organic solvents THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol. The mobile, inexpensive, and Continuously Operating System with liquid flow rates in the low range of microliters per minute can be connected to other detectors or implemented in chemical production line for process control. Figure We present a microfluidic device for highly efficient analytical stripping of organic solvents from water/solvent mixtures at room temperature

  • A microfluidic device for open loop stripping of volatile organic compounds.
    Analytical and bioanalytical chemistry, 2012
    Co-Authors: Benjamin Z. Cvetković, Petra S. Dittrich
    Abstract:

    The detection of volatile organic compounds is of great importance for assessing the quality of water. In this contribution, we describe a miniaturized stripping device that allows fast online detection of organic solvents in water. The core component is a glass microfluidic chip that facilitates the creation of an annular-flowing stream of water and nitrogen gas. Volatile compounds are transferred efficiently from the water into the gas phase along the microfluidic pathway at room temperature within less than 5 s. Before exiting the microchip, the liquid phase is separated from the enriched gas phase by incorporating side capillaries through which the hydrophilic water phase is withdrawn. The gas phase is conveniently collected at the outlet reservoir by tubing. Finally, a semiconductor gas sensor analyzes the concentration of (volatile) organic compounds in the nitrogen gas. The operation and use of the stripping device is demonstrated for the organic solvents THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol. The mobile, inexpensive, and Continuously Operating System with liquid flow rates in the low range of microliters per minute can be connected to other detectors or implemented in chemical production line for process control.

Benjamin Z. Cvetković - One of the best experts on this subject based on the ideXlab platform.

  • A microfluidic device for open loop stripping of volatile organic compounds
    Analytical and Bioanalytical Chemistry, 2013
    Co-Authors: Benjamin Z. Cvetković, Petra S. Dittrich
    Abstract:

    The detection of volatile organic compounds is of great importance for assessing the quality of water. In this contribution, we describe a miniaturized stripping device that allows fast online detection of organic solvents in water. The core component is a glass microfluidic chip that facilitates the creation of an annular-flowing stream of water and nitrogen gas. Volatile compounds are transferred efficiently from the water into the gas phase along the microfluidic pathway at room temperature within less than 5 s. Before exiting the microchip, the liquid phase is separated from the enriched gas phase by incorporating side capillaries through which the hydrophilic water phase is withdrawn. The gas phase is conveniently collected at the outlet reservoir by tubing. Finally, a semiconductor gas sensor analyzes the concentration of (volatile) organic compounds in the nitrogen gas. The operation and use of the stripping device is demonstrated for the organic solvents THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol. The mobile, inexpensive, and Continuously Operating System with liquid flow rates in the low range of microliters per minute can be connected to other detectors or implemented in chemical production line for process control. Figure We present a microfluidic device for highly efficient analytical stripping of organic solvents from water/solvent mixtures at room temperature

  • A microfluidic device for open loop stripping of volatile organic compounds.
    Analytical and bioanalytical chemistry, 2012
    Co-Authors: Benjamin Z. Cvetković, Petra S. Dittrich
    Abstract:

    The detection of volatile organic compounds is of great importance for assessing the quality of water. In this contribution, we describe a miniaturized stripping device that allows fast online detection of organic solvents in water. The core component is a glass microfluidic chip that facilitates the creation of an annular-flowing stream of water and nitrogen gas. Volatile compounds are transferred efficiently from the water into the gas phase along the microfluidic pathway at room temperature within less than 5 s. Before exiting the microchip, the liquid phase is separated from the enriched gas phase by incorporating side capillaries through which the hydrophilic water phase is withdrawn. The gas phase is conveniently collected at the outlet reservoir by tubing. Finally, a semiconductor gas sensor analyzes the concentration of (volatile) organic compounds in the nitrogen gas. The operation and use of the stripping device is demonstrated for the organic solvents THF, 1-propanol, toluene, ethylbenzene, benzaldehyde, and methanol. The mobile, inexpensive, and Continuously Operating System with liquid flow rates in the low range of microliters per minute can be connected to other detectors or implemented in chemical production line for process control.

Madhu Jain - One of the best experts on this subject based on the ideXlab platform.

  • Maintainability Policy for Deteriorating System with Inspection and Common Cause Failure
    International Journal of Engineering, 2013
    Co-Authors: Ashish Mishra, Madhu Jain
    Abstract:

    A B S T R A C T A condition based on preventive and corrective maintenance policy is proposed for a Continuously Operating System. The condition of the System is assumed to deteriorate with time. The model incorporates both deterioration as well as random common cause failures. The deterioration stages are modeled as discrete state processes. The System is put to random inspection to know the condition. The mean times between inspections are exponentially distributed. If the observed condition at an inspection exceeds the threshold (N) deterioration level, the preventive maintenance (PM) is performed, else no action is taken and the System continues to run. The proposed model considers an accumulated deterioration based on increasing intensity for the random failures. The transient solutions using Laplace transform as well as steady state solutions using recursive technique are suggested to compute the state probabilities of the System. Various reliability measures of the System have been established and validated numerically by taking an illustration.

  • Maintainability Policy for Deteriorating System with Inspection and Common Cause Failure (TECHNICAL NOTE)
    International Journal of Engineering - Transactions C: Aspects, 2012
    Co-Authors: Ashish Mishra, Madhu Jain
    Abstract:

    A condition based preventive and corrective maintenance policy is proposed for a Continuously Operating System. The condition of the System is assumed to deteriorate with time. The model incorporates both deterioration as well as random common cause failures. The deterioration stages are modeled as discrete state processes. The System is put to random inspection to know the condition. The mean times between inspections are exponentially distributed. If the observed condition at an inspection exceeds the threshold (N) deterioration level, the preventive maintenance (PM) is performed, else no action is taken and the System continues to run. The proposed model considers an accumulated deterioration based on increasing intensity for the random failures. The transient solutions by using Laplace transform as well as steady state solutions using recursive technique are suggested to compute the state probabilities of the System. Various reliability measures of the System have been established and validated numerically by taking an illustration.

Ashish Mishra - One of the best experts on this subject based on the ideXlab platform.

  • Maintainability Policy for Deteriorating System with Inspection and Common Cause Failure
    International Journal of Engineering, 2013
    Co-Authors: Ashish Mishra, Madhu Jain
    Abstract:

    A B S T R A C T A condition based on preventive and corrective maintenance policy is proposed for a Continuously Operating System. The condition of the System is assumed to deteriorate with time. The model incorporates both deterioration as well as random common cause failures. The deterioration stages are modeled as discrete state processes. The System is put to random inspection to know the condition. The mean times between inspections are exponentially distributed. If the observed condition at an inspection exceeds the threshold (N) deterioration level, the preventive maintenance (PM) is performed, else no action is taken and the System continues to run. The proposed model considers an accumulated deterioration based on increasing intensity for the random failures. The transient solutions using Laplace transform as well as steady state solutions using recursive technique are suggested to compute the state probabilities of the System. Various reliability measures of the System have been established and validated numerically by taking an illustration.

  • Maintainability Policy for Deteriorating System with Inspection and Common Cause Failure (TECHNICAL NOTE)
    International Journal of Engineering - Transactions C: Aspects, 2012
    Co-Authors: Ashish Mishra, Madhu Jain
    Abstract:

    A condition based preventive and corrective maintenance policy is proposed for a Continuously Operating System. The condition of the System is assumed to deteriorate with time. The model incorporates both deterioration as well as random common cause failures. The deterioration stages are modeled as discrete state processes. The System is put to random inspection to know the condition. The mean times between inspections are exponentially distributed. If the observed condition at an inspection exceeds the threshold (N) deterioration level, the preventive maintenance (PM) is performed, else no action is taken and the System continues to run. The proposed model considers an accumulated deterioration based on increasing intensity for the random failures. The transient solutions by using Laplace transform as well as steady state solutions using recursive technique are suggested to compute the state probabilities of the System. Various reliability measures of the System have been established and validated numerically by taking an illustration.

Purnendu K. Dasgupta - One of the best experts on this subject based on the ideXlab platform.

  • Continuous Automated Measurement of the Soluble Fraction of Atmospheric Particulate Matter
    Analytical Chemistry, 1995
    Co-Authors: Poruthoor K. Simon, Purnendu K. Dasgupta
    Abstract:

    A new approach is introduced for the quantitative collection of aerosol particles to submicrometer size. The design and construction of a Continuously Operating System is described. Particles are Continuously transferred to a liquid stream utilizing condensation of supersaturated vapor to promote particle growth followed by collection that relies on impaction and the thermophoretic effect. The automated System is simple to construct and operate and provides quantitative collection of aerosol particulate matter even at a flow rate of 10 L/min. Individual measurements of aerosol particles and soluble gases are achieved by combining the System with a wetted wall parallel plate diffusion denuder