Abstract: Dual mounting head scanner system measures the thickness of a flexible continuous moving web such as paper by employing an optical senor positioned in the upper head to determine the distance between the optical sensor and the upper surface of the paper while a displacement sensor positioned in the lower head determines the distance between the displacement sensor, which includes an RF coil, and a reference surface on the upper head. An air clamp and vacuum source assembly on the operative surface of the lower head maintains the moving web in physical contact with a measurement surface that is incorporated in the operative surface. The optical sensor directs incident radiation onto the web at the measurement surface. Thermal isolation of the two sensors eliminates thermal interactions.

Abstract: An improved differential coat weight technique employs a novel algorithm for measuring the weight of a coating material that has been deposited onto a sheet of substrate. The invention employs dual x-ray or nuclear gauges such that, even though the downstream sensor is never exposed to uncoated sheet substrate, imparting the downstream sensor with the ability to predict results that it would have yielded when measuring the uncoated sheet substrate, leads to the development of a coat weight calibration protocol from which the basis weight of the coating can be ascertained directly from measurements from the upstream and downstream sensors. No subtraction of results is required. Moreover, the two sensors do not need to be re-calibrated whenever the relative proportions of the coating and base substrate change. The technique is particularly suited for applications where the coating material and substrate are made of substances that have very different atomic numbers.

Abstract: An apparatus includes a scanning head configured to move one or more sensors back and forth across a surface of a moving web of material. The apparatus also includes a vibration dampening device configured to reduce vibrations of the one or more sensors when the scanning head moves the one or more sensors back and forth across the surface of the web. The vibration dampening device includes at least one mass and one or more springs configured to create oscillatory movement of the at least one mass. The at least one mass and the one or more springs can be located within a housing that rides on a rail back and forth to move the scanning head across the surface of the web. The at least one mass and the one or more springs can also be located on a web deflector connected to the scanning head.

Abstract: An apparatus for incorporation into time-domain spectroscopy systems that creates a continuous reference whereby a sample pulses' phase and amplitude can be tracked and corrected employs a beam splitter to generate sample and reference pulses. A detector is positioned for receiving the reference radiation pulses that do not interact with the sample. The same detector is also positioned for receiving the sample radiation pulses that emerge from the sample. The apparatus can be readily implemented by being configured between the emitter and detector of a terahertz time-domain spectrometer. The reference pulse is used to trace the changes in time and amplitude of the sample pulse. Since any changes in the reference pulse will most likely manifest in the sample pulse, the reference pulse is monitored and used to correct the sample pulse and thereby reduce the effects of jitter.

Abstract: A method includes identifying a chlorophyll concentration/optical density (CCpOD) value using a chlorophyll concentration measurement of an autotroph culture and an optical density measurement of the autotroph culture. The method also includes identifying a change in the autotroph culture using the CCpOD value. The change in the autotroph culture can be identified by determining whether the CCpOD value falls outside upper and lower control limits. The upper and lower control limits can be identified using a specified number of previously-determined CCpOD values, which can be calculated when the autotroph culture is in a known healthy state. Multiple CCpOD values can be calculated, and an alarm can be generated if a specified number of the CCpOD values (such as one or more) fall outside the upper and lower control limits.

Abstract: Numerous failure modes, causes, and adverse operating conditions on scanner systems exhibit mechanical signatures that are detected by three-axis accelerometers located in the upper and lower sensor heads. A diagnostic system for monitoring the scanning system that detects characteristics of sheet materials during linear translation along a translation axis of a bi-directionally driven mobile detector device includes a vibration sensor configured to measure vibrations generated by various components of the scanning system and to generate vibration signals indicative of operation conditions of the components. Correlating the vibration signals to modes of operations of the components identifies the source, location and severity of potential problems in the scanner.

Abstract: A diffuse reflector of radiation in the near and mid infrared regions includes (i) an assembly that has a reflecting element and a diffusing element that is made of one or more layers of calcium fluoride, sapphire, or alumina; or (ii) a diffusively reflective surface configured as a metallic layer with a rough surface. The diffuse reflector can be incorporated into systems for measuring properties of sheet materials and particularly into optical sensors that include a measurement window configured with one or more of the diffuse reflectors that cause incident radiation from a sensor light source to be diffused and reflected a plurality of times within a layer of material before being detected by the sensor receiver.

Abstract: Scale formation on the electrode(s) of a liquor sensor can be prevented by continuously delivering a water-soluble scale inhibitor or dispersant into the vicinity of the electrodes of a liquor sensor device. Scale inhibitors include, for instance, polymers that are derived from acrylic acid, maleic acid, acrylamide acid, phosphonate, and combinations thereof. An aqueous mixture of scaling inhibitor continuously delivered to the probe tip of the liquor sensor that was placed in a kraft pulping liquor allowed the sensor to operate accurately for over a month without having to be cleaned of scale.

Abstract: A terahertz time-domain spectrometer scanning sensor system includes a transmitter and a receiver that are secured to a mobile scanner head. Optical pump light, in the form of short pulses launched from a stationary laser located remotely from the scanner head, is delivered to the transmitter and receiver through a controlled fiber optic cable arrangement so that variations in temporal pulse relays that are associated fiber optic transmission are minimized. In this fashion, the movement of the fiber optic cable is maneuvered along a defined path so as to control the bends in the cable and thus minimize variations in temporal delays that can otherwise arise as the pulses of light are transmitted through the fiber. Pulses of laser light launched from the laser into the optical fiber will exit the cable with consistent (i) time of arrival, (ii) phase duration, and (iii) polarization state and energy.

Abstract: An optical, non-contact sensor for measuring the thickness or weight of layered products and particularly those that contain a light-reflective substrate incorporates a reflective surface to cause incident radiation from a light source to plurality of time within the layered products before being detected in a receiver. A diffusing element can be incorporated as a diffuse source of illumination. The Lambertian-type light scattering generated by the diffuse element causes the incident light to interact multiple times with the layered product resulting in enhanced sensor sensitivity to selected components in the layered product and measurement error induced by specular reflection of the light from the reflective substrate is minimized.

Abstract: Mobile devices are re-supplied with fluids on a periodic basis thereby eliminating the need to maintain a permanent connection between an external fluid supply and the moving device. Electronic scanning devices generate heat and operate at varying and high temperature conditions that interfere with operations of the scanner heads. Circulating a heat transfer fluid through the sensor head removes excess heat from heat sensitive regions of the sensor head during operations. Once the heat transfer fluid reaches a predetermined temperature or after passage of a predetermined length of time, the scanner head is maneuvered to a docking station where it is coupled to an external heat fluid source where fresh fluid is supplied to the scanner head.

Abstract: Radiation scattering is one of the main contributors to the uncertainty of near infrared (NIR) measurements. Enhanced absorption-measurement accuracy for NIR sensors is achieved by using a combination of NIR spectroscopy and time-of-flight techniques to select photons that are the result of a given mean free path within a moving sample target. By measuring absorption as a function of path length or by windowing signals that are attributable to excessive scattering of NIR radiation within the sample, this technique affords the calculation of more accurate and more universal calibrations. The NIR sensor employs short or ultra-short laser pulses to create NIR that is directed to the moving sample and emerging radiation is detected over time. Windowing effectively truncates non-contributing measurements.

Abstract: Paper and continuous web scanners operate at varying and high temperature conditions that cause distortion of the support beams and ultimately misalignment of the scanner heads. Circulating a heat transfer fluid between the support beams and through segmented fluid channels within the beam allows tuning of the beam's deflection when operating in an uneven thermal environment. The heat transfer rate can be modulated through various techniques, including: (1) varying the flow rate through each channel under manual or automatic control, (2) controlling the inlet fluid temperature of each channel with fluid immersion heaters or coolers, and (3) setting up the flow sequence via distribution channels that are, for example, in parallel, serial, or mixed.

Abstract: Alignment is a critical component for modeling a cross-directional (CD) papermaking process. It specifies the spatial relationship between individual CD actuators to paper quality measurements. Misalignment can occur unexpectedly due to sheet wander or CD shrinkage variation. In certain applications and circumstances, a misalignment of one third (?) actuator zone width can result in significant paper quality degradation. Detecting a misalignment and identifying CD alignment in closed loop are highly demanded in paper mills but these are nontrivial problems. A technique for maintaining proper CD alignment in sheetmaking systems entails monitoring the alignment online, triggering closed loop identification if misalignment is detected, and then deploying the new alignment. No personnel intervention is required.

Abstract: An optical, non-contact sensor for measuring the thickness or weight of layered products and particularly those that contain a light-reflective substrate incorporates a reflective surface to cause incident radiation from a light source to plurality of time within the layered products before being detected in a receiver. A diffusing element can be incorporated as a diffuse source of illumination. The Lambertian-type light scattering generated by the diffuse element causes the incident light to interact multiple times with the layered product resulting in enhanced sensor sensitivity to selected components in the layered product and measurement error induced by specular reflection of the light from the reflective substrate is minimized.

Abstract: A sensor head-transporting roller carriage has four pairs of wheels acting around pivot points at the four corners of the carriage, which is advanced along tracks that are supported by vertical structures. The lateral wheel spacing is chosen in correlation with the track support interval distances such that the vertical travel of all the wheels together is averaged, to be zero. As a result, variations in displacement alignment of the sensor are minimized. In addition, the pivot mechanism results in a fifty percent reduction in the effect of random vertical deflections caused by track debris or wheel concentricity etc. versus standard non-pivoting wheel sets. The roller carriage moves the sensor head along the cross direction to monitoring physical characteristics of a web of material that is moving in the machine direction.

Abstract: A process simulator is provided for simulating the behavior of multi-dimensional non-linear multivariable processes. A multi-dimensional non-linear multivariable model of a process can be generated, such as by using smaller building blocks. One or more inputs are provided to the model, a behavior of the process is simulated in real-time using the model, and one or more outputs of the model are provided. The model could represent a two-dimensional non-linear multivariable model, and the one or more inputs to the model and/or the one or more outputs of the model could be array-based. The process simulator could be formed from multiple components, such as a regulatory loop simulator object, a process model object, a disturbance generator object, and a scanner simulator object. The arrangement of the objects can be flexible and configurable, such as by designing the objects in an object-oriented manner utilizing a sink/source architecture.

Abstract: An in-situ time domain spectroscopy (TDS)-based method (200) for non-contact characterization of properties of a sheet material while being produced by a manufacturing system (700). A time domain spectrometry system (100) and calibration data for the system is provided. The calibration data includes data for transmitted power through or reflected power from the sheet material as a function of a moisture content of the sheet material. At least one pulse of THz or near THz radiation from a transmitter (111) is directed at a location on a sheet material sample (130) while being processed by the manufacturing system (700). Transmitted or reflected radiation associated with at least one transmitted or reflected pulse from the sample location is synchronously detected by a detector (110) to obtain the sample data.

Abstract: Paper and continuous web scanners operate at varying and high temperature conditions. Regulating the temperature within the measurement gap between dual scanner heads during measurement and calibration modes of operation by employing air wipe and sheet guide temperature control assures consistent and accuracy sensor measurements of sheet characteristics. Air wipes blow pre-heated air into the measurement and the sheet guides are heated. The air temperature fluctuations that otherwise caused significant adverse effects on the sensors that measure, for example, the basis weight, ash content, and thickness of the moving sheet, are eliminated.

Abstract: A system includes a signal source that provides a first signal for measuring a gas content of a liquid sample. The system also includes an analyzer that determines the gas content of the liquid sample using a measurement of a second signal, where the second signal is based on the first signal. The system further includes an apparatus with a walled structure having a cavity. The apparatus also includes a piston that pulls the liquid sample into the cavity and pushes the liquid sample out of the cavity. The apparatus further includes at least one measurement window having at least one inner surface exposed within the cavity. The at least one measurement window receives the first signal from the signal source and provides the second signal to the analyzer. The piston could also clean the at least one inner surface, and the piston can include a reference material for calibrating the analyzer.