Abstract: A foam detector generally including a pair of leads positioned adjacent to a surface layer of a fluid so that foam created on a surface layer of the fluid contacts at least one lead and sends a signal to a controller connected to the leads.

Abstract: A method for measuring a degree of association (58) between, and for selectively creating a grouping (40) of, n plurality of spatially referenced physical events (22) of a predetermined physical characteristic. The method includes the steps of assembling n plurality of physical events (26), assembling a universe of possible sample locations (36), determining a reference distribution (54), determining a restricted distribution (56), and determining the degree of association (58) between the n plurality of physical events. Specifically, the physical events each have an indicia of location and a physical characteristic above a threshold. The step (54) of determining a reference distribution is conducted by calculating a test statistic (78) for each of n′ plurality of random allocations (74) of the n plurality of physical events over the selected n plurality of sample locations.

Abstract: An improved field-flow fractionation method and apparatus for the separation of sample species 28 contained in a carrier fluid, wherein

Abstract: A dissolved oxygen sensor having a cathode and anode immersed in an electrolyte is designed to provide a low background current in the sensor when a potential is applied to the cathode. The background current is maintained at a desired level by selecting the area and length of a channel or path of diffusion of residual oxygen in the electrolyte to the cathode. The area (A) of the diffusion channel in relation to its length (L) is selected to be at or below a selected ratio, A/L.

Abstract: A dissolved oxygen sensor having a cathode and anode immersed in an electrolyte is designed to provide a low background current in the sensor when a potential is applied to the cathode. The background current is maintained at a desired level by selecting the area and length of a channel or path of diffusion of residual oxygen in the electrolyte to the cathode. The area (A) of the diffusion channel in relation to its length (L) is selected to be at or below a selected ratio, A/L.

Abstract: The invention comprises a spectroscopic measuring device, a seal for such a device, and a method for sealing such a device. A window having a first and second portion is disposed in a cavity of a housing. The first portion is adjacent to an exterior of the device and has a first diameter less than a second diameter of the second portion, thus forming a shoulder therebetween and defining a gap between the first portion and an interior housing surface. An intermediate ring with a, metallic coating is disposed in the gap adjacent to the shoulder. A retaining ring is disposed in the gap adjacent to the intermediate ring. An exposed surface of the retaining ring is flush with an end housing surface and an exposed sapphire surface. A portion of the exposed retaining ring surface is electron beam welded to a portion of the end housing surface. The housing, intermediate ring, and retaining ring comprise a nickel-molybdenum-chromium alloy.

Abstract: The invention relates to a fiber-optic coupled diffuse reflectance probe that is adapted to detachably connect to a bifurcated fiber bundle. The probe includes a solid light guide for separating the bundle from the target within a small-diameter probe body. A probe of this construction is especially useful for analyzing high temperature and high pressure targets, through relatively small fittings, as is required in polymer extrusion applications. The solid light guide may extend along all or along a lesser portion of the probe body's length. Its fiber-end may be coupled directly to the illumination and detector fibers or indirectly, and at some distance from the fibers, by way of a lens or a hollow light guide. Its target-end may be exposed to terminate in a direct face-to-face relationship with the target, or it may be located behind an intermediate window. The solid light guide is characterized by a target-end refracting surface that minimizes stray light.

Abstract: A pH analyzer is operated to measure conductivity of a solution by applying a substantially DC current having peak values, IREF−PEAK, to a reference electrode of an ion-sensitive sensor having an ion-specific electrode in contact with the solution. The reference electrode is coupled to the ion-specific electrode through the solution. The peak voltage, VION−PEAK, between the ion-specific electrode and the common electrode is measured, and the conductivity of the solution is identified based on C SOL = I REF - PEAK V ION - PEAK .

Abstract: A circuit includes an integrator arranged to integrate input signals over a predetermined sample period based on the cycle period of a power source signal. A delay is coupled to the integrator and is responsive to the end of a sample period to delay start of a successive sample period for a predetermined time delay to cancel low frequency noise induced into the circuit during a prior sample period.

Abstract: A method for measuring a degree of association (58) between, and for selectively creating a grouping (40) of, n plurality of spatially referenced physical events (22) of a predetermined physical characteristic. The method includes the steps of assembling n plurality of physical events (26), assembling a universe of possible sample locations (36), determining a reference distribution (54), determining a restricted distribution (56), and determining the degree of association (58) between the n plurality of physical events. Specifically, the physical events each have an indicia of location and a physical characteristic above a threshold. The step (54) of determining a reference distribution is conducted by calculating a test statistic (78) for each of n′ plurality of random allocations (74) of the n plurality of physical events over the selected n plurality of sample locations.

Abstract: A pH analyzer is operated to measure pH of a solution by applying a reference electrode current, IREF, to a reference electrode of a pH sensor and an ion-specific electrode current, IGLASS, to an ion-specific electrode of the pH sensor. The currents to the reference electrode and ion-specific electrode are multiplexed to avoid cross-talk. Multiplexing the currents provides a more accurate measurement of electrode impedance for diagnostic purpose. A current spike is optionally added to the reference electrode current to discharge any charge in the solution due to the reference electrode current.

Abstract: A inductive conductivity sensor for measuring conductivity of a fluid includes a housing supporting a controlled impedance loop and a transducer. The transducer includes a driver for inducing a first current into the fluid adjacent the housing, and for inducing a second current into the controlled impedance loop. The transducer further includes a detector for inductively measuring the first and second currents.

Abstract: A photometer including an elongated sample cell having a first end, a second end, and a passageway extending between the first end and the second end. Preferably, a ratio of a length of the sample cell to a lateral dimension of the passageway is at least 100 to 1. A first quartz window assembly is located at the first end of the sample cell and has a first port communicating with the passageway proximate to the first end, and a second quartz window assembly is located at the second end of the sample cell and has a second port communicating with the passageway proximate to the second end. An ultraviolet lamp is positioned to emit ultraviolet light through the first quartz window, the passageway, and the second quartz window, and an ultraviolet detector is positioned to receive the ultraviolet light emanating from the second quartz window. Preferably, the sample cell is operated at about ambient temperature, and the volume of the sample cell is no greater than about 0.

Abstract: A method for measuring a degree of association between, and for selectively creating a grouping of, n plurality of spatially referenced physical events of a predetermined physical characteristic. The method includes the steps assembling n plurality of physical events, assembling a universe of possible sample locations, determining a reference distribution, determining a restricted distribution, and determining the degree of association between the n pluralities of physical events. Specifically, the physical events each have an indicia of location and a physical characteristic above a threshold. The step of determining a reference distribution of conducted by calculating a test statistic for each of n′ plurality of random allocations of the n plurality of physical events over the selected n plurality of sample locations.

Abstract: A method of analyzing cells in a carrier solution comprises the following steps: (a) Introducing the carrier solution into a conduit having a surface portion (preferably a substantially flat surface portion). The carrier solution has the cells suspended therein. (b) Allowing the cells to settle on the surface portion, the surface portion including at least one imaging field. In an alternate embodiment, one or more discreet capture zones (e.g., formed from an affinity species immobilized on the substrate or a textured region on the substrate) are formed on the surface portion, and this step (b) comprises capturing the cells in the capture zone. (c) Sequentially interrogating a plurality of the cells in the imaging field with emitted light. (d) Processing resultant light from the imaging field. (e) Generating digital information for each of the plurality of cells from the resultant light. (f) Generating a response file for each of the plurality of cells from the digital information.

Abstract: An electrochemical sensor is described for the analysis of ammonia in air functioning in an amperometric measuring operation. The cell consists of either an immobilized organic electrolyte or a water based electrolyte having in both cases a dissolved Mn2+ salt, which is immediately oxidized by an electrochemical process at a measuring electrode of the cell to Mn4+ ion, if a pH-shift of the electrolyte in the presence of ammonia takes place. The sensor consists of three electrodes comprising a catalytic active carbon measuring electrode, a second carbon auxiliary electrode (counter electrode) in contact with the electrolyte and a third electrode in contact with the electrolyte, which acts as reference electrode. The sensor can be used for ammonia over a wide range and can be adapted for other uses, such as volatile amines.

Abstract: An instrument that analyzes chemical properties of a specimen includes a probe that is used in place on the specimen for spectroscopic analysis. The probe has a probe body with a proximal end and a distal end, and a first optical fiber extends from the proximal to the distal ends. A temperature sensor is included in the probe body and is used so insure that the probe does not exceed a rated temperature limit or to monitor specimen temperature while, simultaneously, chemical composition information of the specimen is transmitted by the optical fiber. The probe can be inserted into a container holding the specimen and can yield both temperature and chemical composition information. The probe includes a plurality of metal coated fibers with the distal ends of the fibers positioned inside a bore in the probe. Braze material is placed on the probe near the bore and the braze material is then brazed to the metal coating on the ends of the fiber.

Abstract: A flame ionization detector burner, includes a housing having a generally cylindrical flame cavity therein extending along a generally longitudinal axis of the housing and a housing exterior with intake passageways communicating between the housing exterior and the flame cavity for passing fuel, air and sample flows into the flame cavity and an exhaust passage communicating between the housing exterior and the flame cavity for passing exhaust gasses out of the flame cavity. A burner carried in the housing cavity receiving the fuel, air, and sample flow generates a flame to ionize the sample. An ion collector plate spaced away from the burner carried in the time cavity collects sample ions and provides an electrical output representative of the sample ions to the housing exterior via an electrical feedthrough between the flame cavity and the housing exterior. The housing includes at least two cylindrical sidewalls removably joined together along the general longitudinal axis of the housing.

Abstract: A substrate such as a porous tape coated with an adsorbent and impregnated with a processing solution which includes a silver salt, an organic acid such as benzenetricarboxylic acid or benzenesulfonic acid (with or without the addition of nitric acid) and a glycol is a sensitive detecting means for hydride gases and is stable upon exposure to light.

Abstract: The invention pertains to a method for measuring the concentration of dissolved gases in a liquid [(39)], especially of CO2 in beverages, in which the liquid [(39)] is passed across the retentate side [(140)] of a membrane [(14)] that is at least partially permeable to the dissolved gas, and [in which] the volumetric flow of the permeated gas on permeate side [(16)] of the membrane [(14)] is determined, the temperature of the liquid [(39)] is measured, and the concentration of the dissolved gas in the liquid [(39)] is calculated from these values. In this, the thickness of the membrane [(14)] can be pre-selected as a function of the flow rate of the liquid [(39)] flowing along the retentate side [(140)].