Abstract: Gas exchange analysis methods and systems utilize a water vapor buffering component including a material configured to buffer water vapor in a flow of a gas, whereby fluctuations in the water vapor content in the flow of the gas are slowed for components downstream from the water vapor buffering component. Components downstream of the water vapor buffering component may include: a first water vapor sensor configured to receive the flow of the gas from the water vapor buffering component and configured to measure a first concentration of water vapor in the gas; a sample chamber configured to receive the gas exiting the water vapor buffering component or the first water vapor sensor and to hold a sample capable of adding or removing water vapor from the gas; and a second water vapor sensor configured to measure a second concentration of water vapor in the gas exiting the sample chamber.

Abstract: Gas exchange analysis methods and systems utilize a water vapor buffering component including a material configured to buffer water vapor in a flow of a gas, whereby fluctuations in the water vapor content in the flow of the gas are slowed for components downstream from the water vapor buffering component. Components downstream of the water vapor buffering component may include: a first water vapor sensor configured to receive the flow of the gas from the water vapor buffering component and configured to measure a first concentration of water vapor in the gas; a sample chamber configured to receive the gas exiting the water vapor buffering component or the first water vapor sensor and to hold a sample capable of adding or removing water vapor from the gas; and a second water vapor sensor configured to measure a second concentration of water vapor in the gas exiting the sample chamber.

Abstract: Multi-functional piezo-actuated flow control systems and methods for use in gas exchange analysis systems such as photosynthesis measurement systems. A fluid valve assembly module includes a housing structure including a plurality of ports and a plurality of fluid passageways interconnecting the ports, and a plurality of piezo-actuated valves in fluid communication with the fluid passageways, each valve including a piezo element that controls flow along a passageway, wherein the passageways and valves are arranged within the housing structure so as to define a fluid control module, which includes a flow swapping component, a flow splitting component and a flow pressurization component.

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: Multi-functional piezo-actuated flow control systems and methods for use in gas exchange analysis systems such as photosynthesis measurement systems. A fluid valve assembly module includes a housing structure including a plurality of ports and a plurality of fluid passageways interconnecting the ports, and a plurality of piezo-actuated valves in fluid communication with the fluid passageways, each valve including a piezo element that controls flow along a passageway, wherein the passageways and valves are arranged within the housing structure so as to define a fluid control module, which includes a flow swapping component, a flow splitting component and a flow pressurization component.

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: System flow path, designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. According to one aspect, a gas exchange analysis system includes a sample chamber defining a measurement volume for analysis of a sample, the sample chamber having an inlet and an outlet, wherein the internal surface(s) of the chamber defining the measurement volume are metal plated. The system also typically includes a source of gas coupled with the inlet of the sample chamber, and a gas analyzer coupled with the outlet of the sample chamber and configured to measure a concentration of one or more gases exiting the chamber, whereby the metal plated internal surface(s) of the chamber reduces sorption of the one or more gases within the chamber.

Abstract: System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. The gas exchange analysis system includes a sample chamber having an inlet and an outlet, wherein the internal surface(s) of the chamber defining the measurement volume are metal plated. The system also typically includes a source of gas coupled with the inlet of the sample chamber, and a gas analyzer coupled with the outlet of the sample chamber and configured to measure a concentration of one or more gases exiting the chamber, whereby the metal plated internal surface(s) of the chamber reduces sorption of the one or more gases within the chamber.

Abstract: System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. According to one aspect, a sensor head for use in a gas exchange analysis system includes a sample chamber defining a measurement volume for analysis of a sample, the sample chamber having an inlet and an outlet, and a flow splitting mechanism located proximal to the sample chamber, the mechanism configured to split a gas flow received at an input port from a remote source to a first output port and to a second output port, wherein the first output port is coupled with the inlet of the sample chamber.

Abstract: A multi-pass optical cell with an actuator for actuating a reflective surface is provided. In one preferred embodiment, an apparatus is provided comprising a first reflective surface, a second reflective surface, and a support structure supporting the first and second reflective surfaces. The support structure positions the first and second reflective surfaces to create an optical cell. The apparatus also comprises a source and a detector, which are positioned such that light emitted from the source is reflected in the optical cell at least one time between the first and second reflective surfaces before reaching the detector. The apparatus further comprises an actuator coupled with and operative to actuate the first reflective surface. In some embodiments, the actuator rotates the first reflective surface. Also, in some embodiments, the multi-pass optical cell is an open path multi-pass optical cell, while, in other embodiments, the multi-pass optical cell is a closed path multi-pass optical cell.

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: A light source reflector includes a structure having three or more internal reflective surfaces defining a first light entry aperture and a second light exit aperture having an area that is greater than the area of the entry aperture. A single light source, or a plurality of uniformly distributed light sources, such as one or more LEDs, located proximal the entry aperture provides illumination, which impinges on the reflective surfaces from the entry aperture and is reflected off the surfaces to provides a substantially uniform illumination pattern exiting the exit aperture. The reflector advantageously allows for the use of a source (e.g., LED(s)) that is smaller than the targeted area of illumination and also avoids creating hot-spots as the reflector does not focus the light, but rather reflects mirror images of the source off of the reflective surfaces.

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: System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. According to one aspect, a sensor head for use in a gas exchange analysis system includes a sample chamber defining a measurement volume for analysis of a sample, the sample chamber having an inlet and an outlet, and a flow splitting mechanism located proximal to the sample chamber, the mechanism configured to split a gas flow received at an input port from a remote source to a first output port and to a second output port, wherein the first output port is coupled with the inlet of the sample chamber.

Abstract: System flow path designs that minimize the impact of gas diffusion sources and sinks. By reducing the magnitude of parasitic sources and sinks, lower rates of photosynthesis and transpiration can be more accurately measured, e.g., without the need for extensive empirical compensation. According to one aspect, a gas exchange analysis system includes a sample chamber defining a measurement volume for analysis of a sample, the sample chamber having an inlet and an outlet, wherein the internal surface(s) of the chamber defining the measurement volume are metal plated. The system also typically includes a source of gas coupled with the inlet of the sample chamber, and a gas analyzer coupled with the outlet of the sample chamber and configured to measure a concentration of one or more gases exiting the chamber, whereby the metal plated internal surface(s) of the chamber reduces sorption of the one or more gases within the chamber.

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.