Abstract: A technique for orienting and binding the head end of phage to a substrate is disclosed. The tail end of the phage is thereby made readily available for bacteria sensing.

Abstract: A thermoelectrically cooled surface-enhanced Raman Spectroscopy (TEC-SERS) fiber optic probe for real-time and in-situ monitoring of volatile organic compounds in gas, liquid, and soil environments. The TEC-SERS probe comprises a sample chamber for receiving a gas sample and a fiber optic Raman probe. The sample chamber comprises an inlet having a semipermeable membrane for separating moisture from the gas sample, a SERS substrate mounted on a thermoelectric cooler, a mass flow device for providing airflow, and an output port. The fiber optic Raman probe is operably coupled to a transparent window in the sample chamber for directing an optical excitation signal to irradiate the SERS substrate and for receiving a SERS optical signal from analytes from the gas sample that are in contact with the SERS substrate.

Abstract: A sensor system employs a thermo-electrically cooled surface enhanced Raman (SERS) structure that is positioned in a sample chamber. Gas or vapor that may contain an analyte of interest is introduced into the sample chamber so that the analyte may come into contact with the SERS structure. The SERS structure may be cooled to facilitate condensation of selected analytes onto the SERS structure. When in contact with each other, the analyte and SERS structure may be optically stimulated by an optical excitation signal to produce a unique spectral response that may be detected by a spectroanalysis system. The spectral response then may be correlated to a specific analyte, i.e., identified.

Abstract: A sensor system employs a thermo-electrically cooled surface enhanced Raman (SERS) structure that is positioned in a sample chamber. Gas or vapor that may contain an analyte of interest is introduced into the sample chamber so that the analyte may come into contact with the SERS structure. The SERS structure may be cooled to facilitate condensation of selected analytes onto the SERS structure. When in contact with each other, the analyte and SERS structure may be optically stimulated by an optical excitation signal to produce a unique spectral response that may be detected by a spectroanalysis system. The spectral response then may be correlated to a specific analyte, i.e., identified.

Abstract: A thermoelectrically cooled surface-enhanced Raman spectrometer sensor system and method for monitoring of volatile organic compounds in gas, liquid, and soil environments. The sensor system comprises a means for providing an inert gas, a thermal desorption tube containing an adsorbate, and a sample chamber with a SERS structure. For liquid and soil environments, the sensor system also comprises a manifold having a semipermeable membrane for separating moisture from an analyte. An optical module mounted to the sample chamber directs an optical excitation signal for irradiating the SERS structure and receives a SERS optical emissions signal. Such optical emissions signal may be detected by a spectroanalysis system and correlated to a particular analyte by a control processor, which generates an alert signal containing a message that the presence of analyte has been detected. The control processor may also activate warning device, such as an audible siren or a visual alarm.

Abstract: A method for developing an algorithm for quantifying the hydrocarbon content of aqueous media includes: a) irradiating aqueous test samples containing hydrocarbons and particulates with light so that fluorescent emissions and scattered light signals are emitted from the test samples; b) detecting fluorescent emissions and the scattered light signals emitted from the test samples; c) generating first data signals representing the intensities of the fluorescent emissions, and second data signals representing the intensities and scatter angles of the second data signals; d) storing representations of the first and second data signals to create a data set; e) dividing the data set into training, test, and validation data sets; f) selecting input parameters from the data set; g) defining and training a neural network having hidden node using the training and the test data sets; and h) validating the neural network using the validation data set.

Abstract: A sensor for performing surface enhanced Raman spectroscopy comprises: a) a sensor body having a throughbore; an optical energy source for generating an optical excitation signal; b) a surface enhanced Raman scattering structure that is mounted to the sensor body through which the optical excitation signal is directed for irradiating an analyte, whereupon the analyte generates primary Raman emissions in response to being irradiated by the optical excitation signal, and wherein the surface enhanced Raman scattering structure generates secondary Raman emissions when irradiated by the optical excitation signal; c) an optical detector for generating an output signal that represents the spectral characteristics of the primary and secondary Raman emissions in response to receiving the primary and second Raman emissions; and d) a processor for substantially filtering the secondary Raman emission from the primary Raman emissions and for generating an output signal representing the analyte.

Abstract: An integrated optical waveguide sensor system includes: an optical waveguide having a monolithic and roughened metallic layer on which a self-assembled monolayer is formed; an optical energy source for generating an optical excitation signal; and a spectrometer for detecting spectra of optical energy emitted from the optical waveguide. The waveguide facilitates multiple SERS responses resulting from interactions between the optical excitation signal and an analyte of interest that may be present on the surface of the self-assembled monolayer. Thus, the sensor system provides a sensor for detecting organic contaminants with a sensitivity of ppm and even ppb in some cases.

Abstract: A method for detecting chemical contamination in subsurface environments. The method is implemented using a video imaging system incorporated into a probe than be pushed into soil to collect in situ images. The method is particularly useful for identifying non-aqueous phase liquids (NAPLs) contaminants. Immiscible globules of NAPLs can be detected in the in situ images based on differences in shape and/or color with respect to the soil background. Alternatively, indicator dyes that partition the NAPLs can be released from the sensor probe so that the NAPLs are rendered more easy to detect due to changes in color or a specific fluorescence emission.

Abstract: A sensor for performing surface enhanced Raman spectroscopy (SERS) includes a sensor body having a throughbore; a window mounted to the sensor body that is coterminous with the throughbore; surface enhanced Raman scattering structure mounted to the window; an optical energy source for generating an optical excitation signal; a first optical fiber mounted in the throughbore for directing the optical excitation signal through the surface enhanced Raman scattering (SERS) structure; a second optical fiber mounted in the throughbore for receiving primary Raman emissions generated when an analyte in contact with the surface enhanced Raman scattering structure is irradiated by the optical excitation signal; and an optical detector for generating an optical signal representing the primary Raman emissions.

Abstract: A system for quantifying the petroleum content of aqueous media includes a sample cell; a first light source for generating a first light signal that stimulates fluorescent emissions when the first light signal irradiates hydrocarbons present in an aqueous solution in the sample cell; a spectral detector for generating a first electrical signal that represents spectral components of the fluorescent emissions in response to detecting the fluorescent emissions that are emitted from the sample cell; a second light source for generating a coherent light signal that is transformed into scattered light signals when the coherent light irradiates oil droplets in the aqueous solution; a detector for generating a second electrical signal in response to detecting scattered light signals emitted from the tube, where the second electrical signal represents the intensities and scatter angles of the scattered light signals; and a processor for determining a particle size distribution of the oil droplets from the second elec

Abstract: A surface enhanced Raman scattering structure may be used for detecting analytes such as organic contaminants in air and aqueous environments, and metallic and anionic contaminants in water. The structure is fabricated by etching a surface of a glass substrate to form a roughened surface; creating an adhesion layer on the roughtened surface; forming metal islands, such as gold, silver, or copper, on the adhesion layer to create a composite structure; and placing the composite structure in a thiol solution to form a self-assembled monolayer over the metal islands. The thiol solution is selected to attract an analyte of interest. The roughened surface enhances the SERS response of the structure and preferably has an average surface roughness that does not exceed about 2500 Å and a periodicity that does not exceed about 12.5 microns.

Abstract: A LIBS cone penetrometer comprises a decoupling mirror to separate an excitation signal and a response signal, an optical fiber arranged with the decoupling mirror for receiving the excitation signal from an energy source and transmitting the response signal from a sample surface, and a cone penetrometer probe connected to the distal end of the optical fiber. The probe further comprises a collimating lens arranged with the optical fiber for collimating the excitation signal and for directing the response signal into the optical fiber. An internally reflecting prism is aligned with the collimating lens to deflect the excitation signal and the response signal between the collimating lens and the sample surface through a window in the side of the probe. A focusing lens is aligned with the prism and the window to reduce the spot size of the excitation signal and to collimate the response signal.

Abstract: A microscope imaging system comprises a tube including a bore and a sidewall having an aperture; an optically transparent window positioned in the aperture; a light source for generating first light signals which are directed at diffuse angles through the window; an imaging system mounted in the bore for detecting second light signals which enter the bore through the window; and a first lens system for focusing the second light signals onto the imaging system. The system may also include a focusing system for changing the distance between the imaging system and the first lens system, and a fluid delivery system for ejecting a chemical indicator reagent from the probe as it is being deployed through the ground. The reagent is dispersed from the tube in the vicinity of the optical window so that it comes into direct contact with the soil outside the tube near the window.

Abstract: An improved fiber optic Raman sensor (FORS) provides high sensitivity and fective rejection of Rayleigh backscatter and background Raman emissions. Multiple receiving optical fibers are arranged around a transmitting optical fiber to increase the sensitivity of the sensor to Raman emissions from an analysis sample. A Raman emission filter is coupled to the transmitting fiber for preventing output of Raman emissions from the optical fiber to the sample, and a Rayleigh line filter is coupled to the receiving optical fibers for removing Rayleigh line energy emitted by the analysis sample. Rayleigh backscatter emitted by the analysis sample is reduced by orienting the sensor at an appropriate angle with respect to the surface of the sample.

Abstract: A spectroscopic detector suitable for detecting oil spills in an aquatic environment includes a buoyant container having an optical window; an optical energy generator mounted in the container for directing an optical energy beam through the window; an optical detector for generating an output signal in response to detecting a second optical energy beam received in the container through the window; and a beam splitter for directing the second optical energy beam to the optical detector. The generation of the optical energy beam and operation of the optical detector may be time gated to reduce thermal noise and isolate the sampled optical energy from background light. The optical energy beam preferably has UV components which inhibits the formation of biological organisms on the optical window.

Abstract: A method for sampling toxin flux rates across a benthic boundary relies upon deploying an apparatus having a frame which houses a container having an open bottom for isolating a volume of fluid above a benthic fluid boundary. A sampling system periodically samples and stores samples of the isolated fluid and an oxygenation system maintains a constant dissolved oxygen level within the container. The device is then retrieved and the samples analyzed. In this way, the toxin flux rate across the fluid boundary may be determined.

Abstract: A method assures the quantitative or semiquantitative assessment of analytes in soils by in situ optical methods. A determination is made of the optical chemical response factors for chemicals of interest which are added in known amounts to discrete soil matrices (types) and conditions (moisture content) under controlled laboratory conditions to provide predetermined reference signals. A combination probe is provided with an optical chemical sensing device that produces chemical concentration signals representative of the concentration of a chemical of interest in a soil sample and further is provided with a strain gauge sensing device that produces strain gauge signals representative of soil type and optionally, condition of the soil sample. The combination probe is inserted into the soil sample and the optical chemical sensing device produces the chemical concentration signals and the optical strain gauge sensing device, simultaneously and in parallel, produces the optical strain gauge signals.

Abstract: A method determines the concentration of a chemical of interest in a solution. A permeable membrane is placed in the solution and a ligand is exuded through the membrane to continually renew the ligand at the surface of the membrane which is in contact with the solution. Complexes of the ligand with the chemicals of interest are formed where the ligand renewed membrane is in contact with the solution. Illuminating the ligand renewed membrane with radiation from a distance from the membrane induces a fluorescence by the formed complexes on the ligand renewed membrane by the illuminating radiation. The fluorescence from the illuminated complexes on the ligand renewed membrane are detected from a distance from the membrane to provide a determination of the concentration of the chemical of interest in the solution.

Abstract: A fiber optic based chemical sensor detects chemical species in solution. A fluorogenic indicator is forced through an ultrafiltration membrane into an analyte solution. Complex formation between indicator molecules and target ions occurs at the membrane-solution interface where light from a bifurcated fiber optic cable stimulates fluorescence. Fluorescent emission from a sample is transmitted back up the fiber optic cable to a linear photo diode detector. The sensor responds linearly to increasing and decreasing concentration changes on time scales of one second. Chemical modification of an indicator solution enhanced sensitivity.