A gas analyzer uses continuous sonic signals through a conduit to determine the composition of a gas in the conduit. A transmitting transducer drives sonic signals at a fixed frequency and a second transducer receives the sonic signals. The phase shift between two signals corresponds to the speed of sound through the gas and is related to the composition of the gas. The electronic versions of these signals are processed by lowering, or dividing, the fixed frequency which expands the range of phase shift measurement and allows the determination of an expanded range for the gas composition. In an ozone generation system, the gas analyzer is highly suitable for determining the composition of gases derived from air as a gas of known composition and a calibration point.

An object of the invention is to provide a gas detection system that does not require customization of an odor sensor depending on an environment. The gas detection system includes a sensor array including a plurality of sensors having different characteristic sensitivities, a pre-processing unit configured to convert each of sensor output values acquired from the sensors constituting the sensor array into an output ratio as a ratio of the output value to a predetermined value, and an odor determination processing unit configured to determine, by comparing a normal range generated based on a result of executing cluster analysis on an output ratio acquired from each of the sensors constituting the sensor array in the past with the output ratio obtained by the pre-processing unit executing the conversion, whether the output ratio is within the normal range.

Devices and techniques related to landfill gas extraction are disclosed. A technique for controlling extraction of landfill gas from a landfill through a gas extraction system is described. The method may include measuring a plurality of values indicating conditions associated with the landfill; computing, based at least in part on the plurality of values and on a model of the landfill, a predicted future state of the landfill; determining, based at least in part on the predicted future state of the landfill, one or more control parameters for one or more respective control devices configured to control operation of the gas extraction system; applying the one or more control parameters to the one or more respective control, and with the one or more control devices, controlling extraction of the landfill gas from the landfill based, at least in part, on the one or more respective control parameters.

A method of assessing the impact of a test perfume composition on the well-being of human subjects is provided, as well as a method of preparing or optimizing a perfume composition for enhancing the well-being of a human subject, perfume compositions that enhance the well-being, and consumer products containing them.

An air sample collection apparatus and methods for operating the air sample collection apparatus are provided. The air sample apparatus comprises a plurality of air canisters comprising at least a first canister and a second canister, a multi-position valve comprising an outlet, and an inlet region, which are fluidly connected to a plurality of ports. Each respective port is fluidly connected to a canister of the plurality of air canisters, a pump operable to provide pressurized sample air to the inlet region of the multi-position valve, and a computing device operable to open and close each respective port fluidly coupled to each canister of the plurality of canisters.

This method comprises the following steps retrieving data about amounts of at least one gas, said data being measured in the atmosphere at a distance from the source along a plurality of lines parallel to a first direction; integrating the amounts read on each line in the first direction in order to obtain an integrated overall amount on each line; integrating the product of the integrated overall amounts on each line and a wind speed present on the line in a second direction perpendicular to the first direction, in order to obtain a raw flow of gas; determining the flow of gas emitted by the source based on the raw flow of gas.

A method for estimating a mapping of the concentration of an analyte in an environment uses sensors distributed in the environment. Each sensor generates a measurement of the analyte concentration at various measurement instants, which measurements are carried out by each sensor at each measurement instant, forming an observation vector, each term of which corresponds to a measurement arising from a sensor. The environment is spatially meshed with a plurality of mesh cells. The analyte concentration at each mesh cell, at each measurement instant, forms a “state vector,” each term of which corresponds to an analyte concentration in a mesh cell. A “global bias” is determined and used to correct the state vector to obtain a “debiased state vector.” The state vector is also corrected by a local correction vector as a function of a correction vector.

The following is an apparatus and a method that enables the automated collection and identification of airborne particulate matter comprising dust, pollen grains, mold spores, bacterial cells, and soot from a gaseous medium comprising the ambient air. Once ambient air is inducted into the apparatus, aerosol particulates are acquired and imaged under a novel lighting environment that is used to highlight diagnostic features of the acquired airborne particulate matter. Identity determinations of acquired airborne particulate matter are made based on captured images. Abundance quantifications can be made using identity classifications. Raw and summary information are communicated across a data network for review or further analysis by a user. Other than routine maintenance or subsequent analyses, the basic operations of the apparatus may use, but do not require the active participation of a human operator.

Methods and apparatus for detecting biological agents suspended in air in real time. A method includes emitting towards an air sample a beam of monochromatic polarized light whose wavelength corresponds to an absorption maximum of a biological molecule. The method further includes receiving, at different scattering angles, the scattered light beam after passing through the sample and determining that there are particles in the sample that contain the biological molecules of interest if the intensity of the scattered light has a substantially higher peak than the rest of the scattered light. The amount of the biological molecules is then estimated according to the amplitude of the peak. The size of the particles containing the biological molecules is also estimated as a function of the scattering angle where the peak was detected.

A method for indoor biological detection of a monitored space is provided including collecting and entering monitored space information to determine density and location of sensors for monitoring air for an aerosol plume, distributing the sensors throughout the space, monitoring air and detecting and characterizing a plume event, determining a source location, collecting and preparing an air sample upon the detection of the plume event, and assaying the air sample to identify a hazardous release utilizing a field screening device. The method continues with the steps of initiating a precautionary response for the hazardous release characterizing the plume as biological or non-biological and initiating a protective response. A system is also provided.