Abstract: Active compensation designs to offset the impact of gas diffusion sources and sinks in a photosynthesis and transpiration measurement system are disclosed. A sensor head for use in a gas exchange analysis system includes an active, piezoelectric flow splitting device for splitting a flow between a sample chamber and bypass pathway. The active flow splitting device is controlled by feedback from a downstream flow meter. A continuous measurement system for rapidly and accurately surveying large numbers of samples is described.

Abstract: Active compensation designs to offset the impact of gas diffusion sources and sinks in a photosynthesis and transpiration measurement system are disclosed. A sensor head for use in a gas exchange analysis system includes an active, piezoelectric flow splitting device for splitting a flow between a sample chamber and bypass pathway. The active flow splitting device is controlled by feedback from a downstream flow meter. A continuous measurement system for rapidly and accurately surveying large numbers of samples is described.

Abstract: Active compensation designs to offset the impact of gas diffusion sources and sinks in a photosynthesis and transpiration measurement system are disclosed. A sensor head for use in a gas exchange analysis system includes an active, piezoelectric flow splitting device for splitting a flow between a sample chamber and bypass pathway. The active flow splitting device is controlled by feedback from a downstream flow meter. A continuous measurement system for rapidly and accurately surveying large numbers of samples is described.

Abstract: Methods, devices, and systems for measuring carbon assimilation based on simultaneous or near-simultaneous measurements of chlorophyll fluorescence and stomatal conductance of plant. A sample containing chlorophyll, such as a plant leaf, is illuminated with light, e.g., in the form of a single saturating pulse or multiple pulses, and chlorophyll fluorescence and stomatal conductance of the chlorophyll sample are measured. A porometer or infra-red gas analyzer is used to measure stomatal conductance and a photodetector is used to measure fluorescence. A carbon assimilation value for the chlorophyll sample is determined using the measured chlorophyll fluorescence and the measured stomatal conductance.

Abstract: Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: Active compensation designs to offset the impact of gas diffusion sources and sinks in a photosynthesis and transpiration measurement system are disclosed. A sensor head for use in a gas exchange analysis system includes an active, piezoelectric flow splitting device for splitting a flow between a sample chamber and bypass pathway. The active flow splitting device is controlled by feedback from a downstream flow meter. A continuous measurement system for rapidly and accurately surveying large numbers of samples is described.

Abstract: Gas analyzer systems and methods for determining gas flux in a short intake tube configuration without using any Webb-Pearman-Leuning density correction. Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: Gas analyzer systems and methods for determining gas flux in a short intake tube configuration without using any Webb-Pearman-Leuning density correction. Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: A method and apparatus are provided for maintaining pressure inside a closed chamber equal to the changing outside pressure, detecting leaks in the plumbing (i.e., air handling system) of a trace gas flux measurement system, and estimating the kinetic volume, e.g., of such a system.

Abstract: A method and apparatus are provided for maintaining pressure inside a closed chamber equal to the changing outside pressure, detecting leaks in the plumbing (i.e., air handling system) of a trace gas flux measurement system, and estimating the kinetic volume, e.g., of such a system.

Abstract: Gas analyzer systems and methods for measuring concentrations of gasses and in particular dry mole fraction of components of a gas. The systems and method allow for rapid measurement of the gas density and/or dry mole fraction of gases for a number of environmental monitoring applications, including high speed flux measurements. A novel coupling design allows for tool-free removal of a cell enclosing a flow path to enable in field cleaning of optical components.

Abstract: A method and apparatus are provided for maintaining pressure inside a closed chamber equal to the changing outside pressure, detecting leaks in the plumbing (i.e., air handling system) of a trace gas flux measurement system, and estimating the kinetic volume, e.g., of such a system.

Abstract: To measure water vapor and carbon dioxide, a gas analyzer includes a light source, a reference flow cell, a sample flow cell, a detector and a source of gas. The light source, flow cells and detector are arranged so that the detector detects light transmitted from said light source through the flow cells. The flow cells have folded paths for the light. A reference signal is subtracted from a sample signal to obtain an independant variable. Carbon dioxide and air mixed with carbon dioxide are supplied as required. The carbon dioxide is supplied from a container through capillary tubes. Heat is applied to the tubes to control the flow rate. A signal representing gross concentration of the carbon dioxide as a dependant variable is obtained from said independent variable from an empirically determined polynomial.

Abstract: To measure water vapor and carbon dioxide, a gas analyzer includes a light source, a reference flow cell, a sample flow cell, a detector and a source of gas. The light source, flow cells and detector are arranged so that the detector detects light transmitted from said light source through the flow cells. The flow cells have folded paths for the light. A reference signal is subtracted from a sample signal to obtain an independant variable. Carbon dioxide and air mixed with carbon dioxide are supplied as required. The carbon dioxide is supplied from a container through capillary tubes. Heat is applied to the tubes to control the flow rate. A signal representing gross concentration of the carbon dioxide as a dependant variable is obtained from said independent variable from an empirically determined polynomial.

Abstract: To measure water vapor and carbon dioxide, a gas analyzer includes a light source, a reference flow cell, a sample flow cell, and a detector. The light source, flow cells and detector are arranged so that the detector detects light transmitted from said light source through said reference flow cell and through said sample flow cell and generates a reference signal representing the light transmitted through a reference gas in said reference flow cell and a sample signal representing the light transmitted through a sample gas in said sample flow cell. The reference signal is subtracted from the sample signal to obtain an independant variable. A signal representing gross concentration of the carbon dioxide as a dependant variable is obtained from said independent variable from a stored empirically determined third power polynomial. The polynomial includes terms having at least first, second and third powers of said independant variable.