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: 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: In one preferred embodiment, a gas analyzer is presented that focuses light beams through gas cells without reflecting the light beams off the walls of the cells. By eliminating wall reflections, dirt or debris on the walls of the cells will not result in inaccurate gas concentration measurements. In another preferred embodiment, a gas analyzer is disclosed having removable gas cells, which allows a user to easily clean the cells instead of returning a contaminated gas analyzer to service personnel for cleaning. In yet another preferred embodiment, a gas analyzer has a purged gas flow channel between source and detector sections of the analyzer to remove contaminants that can result in inaccurate gas concentration measurements. In an additional preferred embodiment, a gas analyzer is disclosed which has a heat exchanger to equilibrate the temperature of incoming air to the temperature of the analyzer's gas cells, thereby avoiding temperature-based errors in gas concentration measurements.

Abstract: The present gas analyzer allows for the effective measurement of the concentration of one or more gases or vapors within a sample. The gas analyzer utilizes a plurality of reference filters that are located between the source and the sample region to enhance the measurements associated with the sample filters. The gas analyzer also utilizes a gas channel to facilitate the circulation of scrubbed gas between two separate housing sections.

Abstract: To sequence DNA, DNA samples marked with flourscent infrared dye are applied at a plurality of locations for electrophoresing in a plurality of channels through a gel electrophoresis slab. The channels are scanned with a laser and a sensor, that include a microscope focused on the gel slab. The focal point and slab are adjusted with respect to each other so that the focal point of the microscope remains on the gel slab during a scan. The data from the scan is directly used to amplitude modulate density readings on a display, and the scan is displayed in a horizontal sweep of a cathode ray tube, whereby said cathode ray tube provides intensity displays of bands representing DNA. Different sizes of glass gel sandwiches may be mounted to the same console for different sequencing tasks.

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 sequence DNA, DNA samples marked with fluorescent infrared dye are applied at a plurality of locations for electrophoresing in a plurality of channels through a gel electrophoresis slab. The channels are scanned with a laser and a sensor, that include a microscope focused on the gel slab. The focal point and slab are adjusted with respect to each other so that the focal point of the microscope remains on the gel slab during a scan. The data from the scan is directly used to amplitude modulate density readings on a display, and the scan is displayed in a horizontal sweep of a cathode ray tube, whereby said cathode ray tube provides intensity displays of bands representing DNA. Different sizes of glass gel sandwiches may be mounted to the same console for different sequencing tasks.

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.

Abstract: To measure the amount of carbon dioxide in a mixture of gases, a source of infrared light includes a porous getter emitted formed of an inner tungsten heater with a layer of sintered together zirconium and carbon powder covered with spectrographic grade carbon over at least 50 percent of its surface serving as a getter and an emitter of infrared light. It is mounted within a vacuum and emits light in a strong spectrum including light having a bandwidth of at least 150 nanometers with a center point of substantially 4.2 micrometers. The light is transmitted through reference and sample flow cells each including a corresponding one of a reference gas and a sample gas onto a photosensor. The light source includes a reflector located within a range of no more than 1 centimeter from the emitter getter for reflecting heat back to said emitter getter at least 50 percent of its surface and has a window aligned with said infrared light sensor with an opening of area of between 0.05 to 20 square millimeters.

Abstract: To measure stomatal resistance of a leaf, signals are obtained from: (1) a small thermocouple positioned adjacent to the leaf in a cuvette to measure temperature of the leaf without conducting excessive heat; (2) a thermistor in the cuvette chamber; and (3) a moisture sensor in the chamber. The moisture signal automatically controls a magnetically operated bypass valve from a source of air flowing through the cuvette chamber so that the moisture remains constant while the flow rate of the air is varied. The flow rate is measured in a flow meter having two laminar paths in series, composed of equal-length equal-diameter tubes but differing in the number of tubes, with the flow rate being measured in a different one of two tubes in each path for different scale measurements.