Abstract: A method of determining a need to perform regeneration of a diesel particulate filter in a diesel engine exhaust predicts a soot load of a diesel particulate filter with a pressure change based soot load estimate based upon a pressure change across the diesel particulate filter at a first time and a second time. A restriction sensitivity for the diesel particulate filter is calculated based upon the pressure change across the diesel particulate filter at the first time and the second time. The method transitions from the pressure change based soot load estimate to a model based soot accumulation estimate of the soot load of the diesel particulate filter upon the restriction sensitivity falling below a predetermined threshold. Regeneration of the diesel particulate filter is requested after the estimated soot level reaches a preset level based upon the soot accumulation model.

Abstract: Liquid sample collector interface, comprising a cap detachably interlocked with housing, with the cap having a filter chamber that accommodates a filter with a large surface area that extends beyond an end of the filter chamber for easy removal of the filter without the use of tools.

Abstract: The present invention discloses a portable sampler for collecting an atmospheric sample. In one implementation, the portable sampler includes a portable housing with an interior portion; a sample inlet communicating between an area outside the housing and the interior portion of the housing; a sample cartridge in fluid communication with the sample inlet and adapted to store the atmospheric sample, the sample cartridge being removably secured within the housing; a pump disposed within the housing and in fluid communication with the sample inlet, the pump being arranged to draw the atmospheric sample from the area outside the housing into the sample cartridge through the sample inlet; and a carrier gas inlet communicating between the area outside the housing and the sample cartridge, the carrier gas inlet being configured to couple with a carrier gas source for sweeping the atmospheric sample from the sample cartridge into an analyzer while the sample cartridge is secured within the housing.

Abstract: A method, apparatus and system for obtaining a sample of a fluid solids, such as a coke and hydrocarbon mixture, from a fluid solids process is provided. A sample vessel is provided that contains a first end, a second end, an aperture in the first end and an interior cavity. A cooling device can be provided for cooling material in the interior cavity of the sampling vessel. In operation, fluid solids can be routed through the aperture and collected in the interior cavity. The collected sample material can then be cooled by the cooling device and used for testing.

Abstract: A sampling and analysis device comprises a housing, a sampling region and an analysis region being defined within the housing. The housing has at least one aperture to allow fluid ingress to and egress from the sampling region. A filter is disposed within the housing, and is movable inside the housing between a sampling position, located in the sampling region, and an analysis position, located in the analysis region.

Abstract: The invention relates to a method for depositing samples in modules, in particular, in kits, in addition to an adapter. The inventive adapter (1) is embodied in such a manner that an injection needle can be received in a liquid-tight manner. It is connected in a liquid-tight manner to the low-lying module or kit (20) and enables a continuous flow of samples.

Abstract: Particles are removed from a fluid stream, such as air, and are deposited on one or more collection surfaces. A pre-filter can be employed to reject oversized particles and contaminants, such as rain and insects. A concentrator is employed to increase a concentration of particles larger than a pre-defined particle size in at least a portion of the fluid, producing a concentrated volume of fluid. The concentrator and pre-filter can, for example, be virtual impactors. The concentrated volume of fluid/air is directed to the collection surface(s), where particles in the concentrated volume of air are deposited. In at least one embodiment, the collection surface is a bed of beads, reducing loss of particles that might occur due to particles bouncing from a single collection surface. A sampling component removes a portion of the deposited particles to generate a sample, which is analyzed by an analytical component.

Abstract: The present invention allows for increased volumetric flow rates relative to current commercially available technology in battery-powered PM sampling devices while vastly simplifying the operation of that device. This will allow for the capture of more PM in a shorter amount of time by allowing a shorter sampling duration and finer scale sampling or the collection of meaningful levels of PM in areas with unusually low concentrations of pollution. Further, the invention can be applied to any aerosol sampling device which requires a fixed rate of volumetric gas flow drawn through an aerosol sampling inlet.

Abstract: A fluid delivery system including a filter for filtering solid particles from a liquid sample, the filter including a first filter member configured to filter solid media from a liquid sample, a second filter member fluidly connected to the first filter member, and a third filter member fluidly connected to a downstream end of the second filter member. The second filter member is configured to filter relatively smaller solid media from the liquid sample than the first filter member, and the third filter member is configured to filter relatively larger solid media from the liquid sample than the second filter member. In various aspects, the system includes a displacement-type plunger needle to draw sample fluid from a vial, a cantilevered carousel for rotatably supporting an array of sample holding vials, and a support for supporting the carousel. Method of using the fluid delivery system are also disclosed.

Abstract: A method of processing a sample may include introducing a sample into a vessel, the vessel having proximal and distal ends, the sample being introduced into the proximal end of the vessel; incubating the sample in the vessel with a substance capable of specific binding to a preselected component of the sample; propelling components of the incubated sample, other than the preselected component, toward the proximal end of the vessel by clamping the vessel distal to the incubated sample and compressing the vessel where the incubated sample is contained; propelling the preselected component toward a distal segment of the vessel by clamping the vessel proximal to the preselected component and compressing the vessel where the preselected component is contained; and mixing the preselected component with a reagent in the distal segment of the vessel.

Abstract: A smoke evaluation device includes a manifold in fluid communication with a source of smoke, and a first sampling line and a second sampling line in fluid communication with the manifold. The first sampling line and the second sampling line are arranged to convey parallel smoke flows. A first filter station is located in the first sampling line, and is adapted to support a filter paper in fluid communication with the smoke. A first circuit board station is located in the second sampling line, and is adapted to support a circuit board in fluid communication with the smoke.

Abstract: A system for monitoring fluid quality within a fluid flow in real time, is disclosed. The system comprises (a) a fluid filter incorporated into the fluid flow; the filter is adapted for filtering the fluid flow; (b) sensor means adapted for measuring a difference between an upstream pressure and a downstream pressure of the fluid flow; and (c) control means. The control means is adapted for estimating the fluid quality on a base of measuring a time period of rise in the pressure difference at the filter over a predetermined value.

Abstract: A sample probe includes a sample probe tip filter and a deflector disposed in relation to the sample probe tip filter, where the deflector is operable to deflect particles in a gas stream away from the sample probe tip filter.

Abstract: A sample probe includes a sample probe tip filter. The sample probe also includes a shield disposed in relation to the sample probe tip filter, the shield being operable to deflect particles in a gas sampling stream away from the sample probe tip filter. The shield has at least one opening that allows the gas within the gas sampling stream and certain ones of the particles in the gas sampling stream both traveling in a substantially flow reversal direction to a primary direction of the gas sampling stream to enter the shield and contact the sample probe tip filter.

Abstract: A collector line for leakage monitoring and leakage location at a plant includes a carrier tube having a wall with openings formed therein, which are sealed with silicone rubber. This makes it possible to use the collector line during low ambient temperatures. A device and a method for leakage monitoring and leakage location and a pipeline having a collector line, are also provided.

Abstract: Apparatus for preparing a biological sample for PCR analysis has an inlet (4) for receiving the sample (15) and a sieve (13) through which the sample is forced by screwing down an inlet cap (16). A lysis solution between two rupturable seals (11 and 12) is effective to disrupt the cells of the sample and release nucleic acid. The apparatus is mounted releasably on a PCR machine (2) having a motor (2?) releasably coupled with a drive mechanism (3, 36,40) in the apparatus to effect a rotary and a vertical up and down movement of its components (30, 31, 32, 42). The apparatus has a transparent cuvette (5) and a needle (71) extending to the lower end of the cuvette, by which the prepared sample is dispensed to the cuvette for PCR analysis.

Abstract: A cap having a core structure dimensioned to receive a pipette therethrough. The cap includes two axially aligned frangible seals that are affixed to the core structure in a spaced-apart relationship. The frangible seals include a foil layer and are constructed so that air passageways are formed between the frangible seals and a pipette tip when the pipette tip penetrates the frangible seals. The cap optionally includes a filter interposed between the first and second frangible seals.

Abstract: A method for analysis of solvent evaporation patterns includes: continuously evacuating the gas of a single-component or multicomponent solvent evaporated under desired evaporation conditions from an object containing the single-component or multicomponent solvent housed in an airtight container, with evacuation means from the airtight container to an exhaust path connected to an exhaust port of the evacuation means; sampling a gas at predetermined time intervals from a desired point between the airtight container and the outlet of the exhaust path with the continuous evacuation maintained; measuring the solvent gas contained in the sampled gas; and determining an evaporation pattern of the solvent from the object under the desired evaporation conditions, from results of the measurement.

Abstract: A water transport assembly, is provided including a housing having a first chamber therein, which is accessible through an opening in the housing. The housing additionally includes a sample inlet port and a sample outlet port, both of which are in fluid communication with the first chamber. A flat ion exchange membrane is attached to the housing in a plane over the opening in the housing, to seal the opening in a vapor tight seal. Water will pass through the membrane based upon the vapor pressure on each side of the membrane, to either dry or humidify sample passing through the first chamber. When the flat ion exchange membrane is a flat, thin ion exchange membrane it is preferable that the thin ion exchange membrane have a thickness of between about 0.1 and about 3.0 mils.

Abstract: A portable microbial gaseous-fluid sampler includes a gaseous-fluid flow system at least partially supported by a structure. The gaseous-fluid flow system includes a gaseous-fluid intake portion having an intake port, a blower in fluid communication with the intake port, and a gaseous-fluid exhaust portion having an exhaust port. The sampler can further include an exhaust filter operable to substantially filter a totality of the gaseous fluid flowing through the sampler prior to exhausting the gaseous fluid. The sampler also can include a control system operable to control at least gaseous-fluid flow through the sampler, and a remote sampling head.

Abstract: A permeable-wall sample holder provides ventilation of vapor-phase entities between the sample and the exterior of the holder through its wall. The vapor-phase transport across the holder wall supports equilibrium of the sample with the analysis environment.

Abstract: A device for sampling drill cuttings includes a frame, an inclined perforated member mounted on the frame, a sprayer for washing cuttings down over the perforations, and a removable open-topped cuttings collector mounted under the perforated member, the perforated member cooperating with the downstream end of a vibratory screen over which the cuttings pass before translating onto the perforated screen.

Abstract: A fluid testing apparatus and associated method include a testing chamber, a filter storage device and a filter transfer mechanism. The testing chamber has a sample volume, a filtrate collection reservoir, an opening between the sample volume and the filtrate collection reservoir, and at least one port into the sample volume. The filter transfer mechanism positions at least one filter in the opening. The opening is closed and a sample fluid, introduced into the port, at least partially fills the sample volume. The sample volume is pressurized and a filtrate of the sample fluid flows from the sample volume, through the filter into the filtrate collection reservoir. The volume of filtrate passing into the filtrate collection reservoir is measured and the sample fluid from sample volume is discharged. The filtrate is discharged from the filtrate collection reservoir, and the filter transfer mechanism removes the filter.

Abstract: A method of performing chemical analysis is disclosed. The method includes the steps of forming carbide-derived carbon (CDC) material having a plurality of pore size, surface chemistry, and surface electrical properties. An array of the surface functionalized CDCs are used for atmospheric sampling, in which chemicals in the atmosphere are adsorbed on the CDCs. The adsorbed samples are desorbed later for analysis by a plurality of individual mass spectrometers.

Abstract: The invention relates to an air pollution sensor system (1) comprising an air inlet (11), an air outlet (12), a sensor unit (2), and an air displacement device (3). The air displacement device is arranged to establish an air flow (4) from the air inlet through the sensor unit to the air outlet. The sensor unit comprises, a filter (22) for removing airborne pollutants from the air flow. The sensor unit is arranged to generate an output signal (21) based on the amount of airborne pollutants removed from the air flow by the filter. The air displacement device is arranged to be controlled by the output signal, thereby improving the lifetime of the air pollution sensor system by minimizing the amount of pollutants that will be deposited inside the sensor unit when the air pollution sensor system is operated under predetermined conditions.

Abstract: Device for recovering a material to be measured comprising a reservoir filled with a sample holding material impregnated with a sample liquid in which a material to be measured is dissolved and an adsorbing column for adsorbing the material to be measured, wherein the reservoir and the adsorbing column are communicated by a straight pipe, and further communicated with a recovery vessel via a recovery pipe branched out the straight pipe. Accordingly, operations of opening/closing or switching a first valve provided on the in-flow side of the reservoir, a second valve provided on the out-flow side of the adsorbing column, and a third valve provided to a vent hole to the atmosphere in the recovery vessel, make it possible to recover the material to be measured without depositing the material on the valves.

Abstract: Apparatus and methods are described for subsea pipeline servicing, including line-pack testing, physical integrity testing, recovery of damaged sections of pipelines, and product removal from subsea structures. In one embodiment of the invention, a subsea pipeline service skid is provided including at least one sample collection bladder affixed to the skid and in fluid communication with a skid mounted pump dimensioned to pull a sample from the subsea pipeline. In another embodiment, a product removal bladder is provided for removal of the hydrocarbons from a subsea structure.

Abstract: A solute concentration measurement device is disclosed. The device may comprise a filter membrane, an exchange chamber, a sensing chamber, a separator, and a sensor. The device may be configured to be placed in fluid communication with a sample solution containing a solute and a solvent. The filter membrane may provide selective fluid communication between the solution and the exchange chamber. The separator may separate the exchange chamber from the sensing chamber and cause a change in a condition of the sensing chamber corresponding to a change of a condition of the exchange chamber. The sensor may sense the condition pertaining to the sensing chamber and calculate the concentration of the sample solution corresponding to this change.

Abstract: A method of using a finger swipe fluid transfer collection assembly includes providing a finger swipe fluid transfer collection assembly including a base, a test media carried by the base, an inlet for receiving a sample fluid, an outlet, a finger swipe fluid transfer mechanism carried by the base between the inlet and the outlet and including an interior; swiping the finger swipe fluid transfer mechanism with one's finger to impart a negative pressure in the interior of the finger swipe fluid transfer mechanism to draw the sample fluid into the interior of the finger swipe fluid transfer mechanism through the inlet; and swiping the finger swipe fluid transfer mechanism again with one's finger to impart a positive pressure in the interior of the finger swipe fluid transfer mechanism to pump the sample fluid through the outlet and be transferred to the test media.

Abstract: A concentrator that is operable to concentrate particles of target material from a high flow rate sampled airflow into a low flow rate secondary airflow. The concentrator may have an array of radially arranged blades. Each blade may have a sampled airflow inlet that uses centrifugal force to concentrate the particles into a central portion of the sampled airflow passing through it. Downstream, the blade may also have primary airflow outlets and knife-edged secondary airflow inlets that divide the sampled airflow into a pair of lateral, high flow rate primary airflows from which the particles have been depleted, and a central, low flow rate secondary airflow which carries the concentrated particles.

Abstract: A stack-gas measuring apparatus includes a sample introducing unit (sampling unit and heating conduit pipe) for introducing stack-gas, a cooling unit (containing wet filter ) in which dust components in the stack-gas are agglomerated, a filter column containing a filter element made of a polymer material for collecting the dust components, a mist scrubber which is disposed downstream of the filter column and which contains an adsorbent for removing acid mist in the stack-gas, and an analyzer in which the cleaning-processed gas is introduced to measure a particular component in the stack-gas.

Abstract: The measurement is conducted by means of thermogravimetric scales (10) bearing at one end of the beam (20) a catalyst body (30) for catalysing a coking reaction of the tars present in the gas state. Precautions are taken in order to ensure homogeneity and regularity of the sampled gas flow and to guarantee predominant catalysis on the catalytic body (30), the weight increase of which gives the weight of the deposited coke and indirectly the content of tars present in the gas state in the gas to be measured. A calorimetric device (34) for analyzing gases from the coking of the tars provides a complementary and/or additional measurement. The solid tars are filtered beforehand, but their content may be measured by an auxiliary device. Possible application to analyzing gases from biomass.

Abstract: A trace sampling detection system includes a gathering device configured to gather particles through a handle-bar, a gate and an air-stream gatherer. A collection tube is configured to deposit gathered particles from the gathering device onto a portion of a sample media. A carousel wheel that includes the sample media is configured to rotate the sample wheel such that the portion of the sample media including the gathered particles is presented to an exothermic decomposition detector that detects, through an infrared sensor, the decomposition of the gathered particles.

Abstract: A method for environmental monitoring and bioprospecting includes the steps of: (a) utilizing a testing device having: (i) a container having a fluid inlet and outlet, (ii) a plurality of capillary microcosms situated within the container, each of these capillaries having an inlet and outlet that are configured so as to allow for fluid flow through the capillaries, each of these capillaries further having a means for covering its inlet and outlet so as to prevent flow through the capillary, (iii) a pump connected to the container outlet, the pump being configured so as to draw fluid from the surrounding environment into the container's inlet and through the capillaries, (iv) connected to the outlet of the container, a means for collecting the flow through the container, and (v) a check valve connected downstream of the container to prevent the backflow of fluid into the container, (b) adding specified test substances to the device's capillaries, wherein these substances are to be analyzed for their ability to

Abstract: A method of sampling and confining chemical contaminations intended for the chemical analysis of contaminations in particulate and/or molecular form with prior adsorption by a support or trapping in a liquid. The adsorbent support or the contaminated liquid is then held in position in a closed box or sealed container having chemically inert walls. The outside of the closed box or sealed container is brought into contact with a gas at a higher pressure than the pressure inside the box or container and then the temperature inside the closed box or sealed container is regulated from an environment external to the gas.

Abstract: The embodiments disclosed herein relate to diagnostic products, and more particularly to lateral flow devices for detecting, for example, infectious diseases, molecules derived from infectious agents, and toxic substances. In an embodiment, a lateral flow device includes a top portion including a self-sealing test sample port and a self-sealing test reagent port; a bottom portion including a channel sufficiently designed to hold a lateral flow test strip; a test sample well sufficiently designed to accept and filter components of a test sample; a test reagent well sufficiently designed to accept components of a test reagent; and a tilting frame sufficiently designed to press the test reagent well against the lateral flow test strip while simultaneously lifting the test sample well from the lateral flow test strip.

Abstract: A planar omni-directional inlet assembly is provided for installing on a device, such as a dry filter unit, that draws a fluid medium, such as ambient air, to collect particulate matter suspended in the fluid medium onto a filter. The inlet assembly includes an annular platform removably positionable on the device; an annular nozzle to direct the air from the platform; an annular impactor disposed downstream of the nozzle; a housing that disposes the filter downstream of the impactor; and an exit for passing the air from the filter to the device. The impactor presents a flow obstacle for a portion of the particulate matter. The housing directs the air through the filter. The housing includes a base with a first cavity and a lid with a second cavity such that the filter is disposable between the first and second cavities.

Abstract: IMS apparatus has a preconcentrator in an inlet passage. A pressure pulser connected to the interior of a housing applies small alternating negative and positive pressure pulses to the housing so that air is drawn in and out of the inlet passage in a “panting” fashion. This causes analyte to be adsorbed by the preconcentrator but does not allow analyte to enter sufficiently to be ionized and detected. After a time sufficient to accumulate a detectable amount of analyte on the preconcentrator the apparatus switches to a desorb phase. The preconcentrator is heated to desorb the analyte, and the pressure pulser produces a larger negative pulse sufficient to draw the liberated analyte far enough into the reaction region for ionization and detection.

Abstract: An IMS detector has a pin-hole or capillary inlet having a coating of an adsorbent material, such as polydimethylsiloxane, which is adsorbent to an analyte substance of interest. The analyte is adsorbed into the material until a heater is energized to heat the adsorbent material and release the adsorbed analyte substance for detection in a detector.

Abstract: A device for separating at least part of the liquid component of a blood sample and methods thereof are disclosed. Generally, the device includes a container body for receiving the blood sample, a layer of retaining porous material, a layer of separating permeable material. The retaining porous material retains non-liquid components of the blood sample after the non-liquid components have been subjected to centrifugal force which forces them through the separating permeable material into the retaining porous material.

Abstract: An embodiment of the present invention provides an air sampling system for measuring corrosives within an airstream flowing within an inlet system. This air sampling system may include an air sampling unit with a plurality of sampling coupons secured within. Parts of the air sampling system may be externally mounted to the inlet system, allowing for an operator to access the sampling coupons, while the inlet system operates. In operation, an embodiment of the present invention has a sampling line connected to the air sampling system; the airstream flowing within the sampling line passes over the sampling coupons and then returns to the inlet system.

Abstract: The present invention discloses a door-type passenger security inspection apparatus comprising: an air source supplying an air flow; a spraying device for spraying the air flow onto the body and clothes of a passenger being inspected; an air-spray moving device for moving the spraying device; a collecting device for collecting suspicious particles of contraband articles separated from the body and the clothes of the passenger; and a detecting device for detecting the suspicious particles of contraband articles collected by the collecting device. Further, the present invention also provides a method for passenger security inspection on prohibited-articles. With the technical solution of the present inventions contraband articles such as narcotic drugs and explosives may be detected reliably and effectively.

Abstract: A method of cleaning a particle filter, in particular for combustion engines, includes the steps of: —a) applying heat to the interior of the particle filter during a certain time period for burning the trapped particles, —b) removing the burnt particles from the particle filter, —c) measuring the particle filter, wherein the measurements are compared to values of a unused filter of the particular type, and—if the measured values deviate from the values of the unused filter by a predetermined amount, steps a) to c) are repeated until the measured values are within an approval range. A system for performing the method is also disclosed.

Abstract: A method for determining the amount of particulate that has accumulated in a particulate filter, comprising calculating an amount of particulate that has accumulated in the particulate filter on the basis of a physical model that uses measured and/or determined physical quantities, and subjecting the calculated particulate amount to validation on the basis of given validation criteria, the latter step envisaging validation of the calculated particulate amount in the case where said criteria are satisfied, and validation of a substitutive particulate amount which is a function of a previously validated amount and of an admissible rate of variation in the case where said criteria are not satisfied.

Abstract: A beta-ray soot concentration direct readout monitor and a method for determining effective sample. The monitor includes a fume collection cell and a fume mass detection cell. The fume collection cell includes a fume sampling gun, a filter paper and a mechanical control auto form feed structure. The fume sampling gun includes a gathering tube, a pitot tube and a sheath tube. The gathering tube tail of the fume sampling gun is equipped with an upper cavity body and a corresponding lower cavity body. The filter paper passes through space between the upper and lower cavity bodies. A paper supporting gate is provided at the inlet of the lower cavity body. A smoke outlet is equipped at a lower part of the lower cavity body. The sampling area of the soot acquired from the upper cavity body is at least twice with the actual testing area of the filter paper.

Abstract: A gas sampling system having a storage chamber configured to store a gas; a water-impermeable, gas-permeable surface; and an isolating system. The isolating system is configured to have a first and a second position, and the storage chamber is in fluid communication with the water-impermeable, gas-permeable surface when the isolating system is in a first position. The storage chamber is not in fluid communication with the water-impermeable, gas-permeable surface when the isolating system is in the second position. The gas sampling system also has a gas displacement system configured to displace the gas from the storage chamber.

Abstract: Disclosed relates to an electrochemical determination system of glycated proteins, the system comprising: a filtering means for filtering labeled compounds bound to glycated proteins and non-glycated proteins after adding labeling compounds, capable of selectively binding to the glycated proteins to a solution, in which glycated/non-glycated proteins coexist, to be bound all to the glycated proteins; and a quantifying means for quantifying the filtered labeling compounds, not bound to the glycated proteins. The system of the present invention filters the residual labeled compounds left after binding to glycated proteins to quantify, instead of directly quantifying glycated proteins via the known glycated protein determination methods, thus simplifying the configuration of the system that can provide exact determinations with a low cost.

Abstract: A novel multi-gas passive sampler is described, whereby different collection media are packed into one passive sampler to collect a variety of air pollutants (or groups of air pollutants) at the same time. By comparison with known commercially available passive samplers—in which only a single collection medium is used to collect a single air pollutant of or group of air pollutants—the MGPS is more cost effective, convenient to use and more environment-friendly.

Abstract: A collecting line for leakage monitoring in an installation is permeable to a substance to be monitored in at least one subarea extending along the longitudinal direction. The collecting line is formed of at least two subsections that are spaced from a first end of the collecting line. The distance between the second subsection and the first end is larger than the distance between the first subsection and the first end. The permeability to the substance to be monitored is higher in the first subsection than in the second subsection. A device having the collecting line is also provided.

Abstract: A detector for optically detecting biological aerosols in a sample volume using non-imaging optical components (NIOCs) includes a light source configured to stimulate bio-fluorescence of tryptophan or nicotinamide adenine dinucleotide. A first NIOC is disposed adjacent to the light source and is configured to direct light away from the first light source. A detector is configured to detect bio-fluorescence associated with biological aerosols, and a second NIOC is disposed adjacent to the detector and is configured to direct light toward the first detector. In at least one embodiment, each NIOC comprises a compound parabolic collector. In one embodiment, the volume is disposed between the first and second NIOC, and in other embodiments, the volume is disposed distally of both NIOCs. To facilitate volume production, the NIOC can be formed as an integral structure. Preferably, the sample is a volume of a gaseous fluid, such as air.