Abstract: A system for in-situ monitoring of particles in a process fluid includes a flow channel having a window for flowing the process fluid therethrough. The window includes an inner surface having a coating thereon that reduces a buildup rate of the particles on the inner surface. A light source is for directing a polarized beam along a first beam path through the window into the process fluid such that an output beam emerges from the process fluid along a second beam path. A polarizing filter positioned in the second beam path is for filtering the output beam. A photodetector is for detecting the output beam after passing the polarizing filter that generates signals that represent images of the particles in the process fluid. A controller coupled to the photodetector is for analyzing the signals to determine at least one parameter related to the particles in the process fluid.

Abstract: A system for in-situ monitoring of particles in a process fluid includes a flow channel having a window for flowing the process fluid therethrough. The window includes an inner surface having a coating thereon that reduces a buildup rate of the particles on the inner surface. A light source is for directing a polarized beam along a first beam path through the window into the process fluid such that an output beam emerges from the process fluid along a second beam path. A polarizing filter positioned in the second beam path is for filtering the output beam. A photodetector is for detecting the output beam after passing the polarizing filter that generates signals that represent images of the particles in the process fluid. A controller coupled to the photodetector is for analyzing the signals to determine at least one parameter related to the particles in the process fluid.

Abstract: On-line detection of mesophase particles employs a laser diode light source to illuminate a target area with a pulsed laser linearly or circularly polarized probe beam. Analysis of images determines extent of presence the birefringent mesophase particles, which are precursors to coking in catalytic hydrocracking processes. The inherently polarized low-coherence, unfocused but sufficiently collimated, pulsed laser beam yield sharp imaging with high depth of field of very small mesophase particles that are present in a moving, dark reactor liquid environment.

Abstract: On-line detection of mesophase particles employs a laser diode light source to illuminate a target area with a pulsed laser linearly or circularly polarized probe beam. Analysis of images determines extent of presence the birefringent mesophase particles, which are precursors to coking in catalytic hydrocracking processes. The inherently polarized low-coherence, unfocused but sufficiently collimated, pulsed laser beam yield sharp imaging with high depth of field of very small mesophase particles that are present in a moving, dark reactor liquid environment.

Abstract: On-line detection of mesophase particles employs a laser diode light source to illuminate a target area with a pulsed laser linearly or circularly polarized probe beam. Analysis of images determines extent of presence the birefringent mesophase particles, which are precursors to coking in catalytic hydrocracking processes. The inherently polarized low-coherence, unfocused but sufficiently collimated, pulsed laser beam yield sharp imaging with high depth of field of very small mesophase particles that are present in a moving, dark reactor liquid environment.

Abstract: On-line detection of mesophase particles employs a laser diode light source to illuminate a target area with a pulsed laser linearly or circularly polarized probe beam. Analysis of images determines extent of presence the birefringent mesophase particles, which are precursors to coking in catalytic hydrocracking processes. The inherently polarized low-coherence, unfocused but sufficiently collimated, pulsed laser beam yield sharp imaging with high depth of field of very small mesophase particles that are present in a moving, dark reactor liquid environment.

Abstract: A method includes, using at least one processing device, obtaining position measurements and/or tilt angle measurements associated with a tissue web and identifying a stretch measurement associated with the tissue web using the obtained measurements. Identifying the stretch measurement could include using one or more mathematical formulas to calculate the stretch measurement associated with the tissue web using the obtained measurements. The one or more mathematical formulas could be defined using laboratory stretch values of multiple training webs. Different mathematical formulas can be associated with training webs having different characteristics, and the method may further include selecting at least one of the mathematical formulas based on one or more characteristics of the tissue web.

Abstract: A method includes, using at least one processing device, obtaining an image of a web of creped tissue paper and identifying a caliper measurement of the web using the image. The caliper measurement is based on a dominant frequency of the web and a standard deviation of diffusely-reflected light from the web. The dominant frequency of the web can be based on a number of crepe folds having a dominant crepe fold size that fit within a specified unit distance of the web in the image. The dominant crepe fold size can be determined using a discrete auto-covariance function of the image or a second image of the web. The standard deviation can be based on a variation of reflected light from larger crepe structures in the web.

Abstract: A method includes obtaining measurements associated with one or more controlled variables related to a structure of creped tissue paper during production of the creped tissue paper. The method also includes generating at least one control signal that adjusts one or more manipulated variables associated with the production of the creped tissue paper in order to alter the structure of the creped tissue paper. The one or more controlled variables include a number of folds per unit length of the creped tissue paper, a caliper of the creped tissue paper, a macro crepe of the creped tissue paper, and/or a micro crepe of the creped tissue paper. The manipulated variable(s) could include a crepe percentage, a creping blade angle, a flow of sizing agent, and/or a cross direction (CD) profile of nozzle positions associated with a spray boom that sprays sizing agent onto a Yankee dryer.

Abstract: A method includes, using at least one processing device, obtaining an image of a surface having a texture and identifying a dominant size of the texture using a discrete auto-covariance function of the image. A first positive local maximum of the discrete auto-covariance function could be identified. The discrete auto-covariance function could include points associated with positive numbers of whole pixels, and the first positive local maximum of the discrete auto-covariance function could be identified at one of the points. Sub-pixel estimation could also be performed using the point associated with the first positive local maximum and one or more neighboring points. Performing the sub-pixel estimation could include fitting a polynomial curve to the point associated with the first positive local maximum and the one or more neighboring points and identifying a number of whole and fractional pixels associated with a maximum of the polynomial curve.

Abstract: A method includes, using at least one processing device, obtaining position measurements and/or tilt angle measurements associated with a tissue web and identifying a stretch measurement associated with the tissue web using the obtained measurements. Identifying the stretch measurement could include using one or more mathematical formulas to calculate the stretch measurement associated with the tissue web using the obtained measurements. The one or more mathematical formulas could be defined using laboratory stretch values of multiple training webs. Different mathematical formulas can be associated with training webs having different characteristics, and the method may further include selecting at least one of the mathematical formulas based on one or more characteristics of the tissue web.

Abstract: A method includes receiving multiple biased measurements associated with a property of a sheet of material, where the biased measurements correspond to multiple known sheet geometries. The method also includes determining an unbiased measurement associated with the property of the sheet using the biased measurements, where the unbiased measurement corresponds to a nominal sheet geometry. The method further includes storing and/or outputting the unbiased measurement. Determining the unbiased measurement could include performing regression using the biased measurements and their corresponding sheet geometries to identify an estimated value of the property of the sheet at the nominal sheet geometry. The biased measurements can be generated using one or more sensors, and the sheet may not be stabilized during the biased measurement generation. Additional sheet geometries can also be created, such as by varying a tilt angle, a curvature, and/or a position of the sheet.

Abstract: A method includes, using at least one processing device, obtaining an image of a web of creped tissue paper and identifying a caliper measurement of the web using the image. The caliper measurement is based on a dominant frequency of the web and a standard deviation of diffusely-reflected light from the web. The dominant frequency of the web can be based on a number of crepe folds having a dominant crepe fold size that fit within a specified unit distance of the web in the image. The dominant crepe fold size can be determined using a discrete auto-covariance function of the image or a second image of the web. The standard deviation can be based on a variation of reflected light from larger crepe structures in the web.

Abstract: A method includes, using at least one processing device, obtaining an image of a surface having a texture and identifying a dominant size of the texture using a discrete auto-covariance function of the image. A first positive local maximum of the discrete auto-covariance function could be identified. The discrete auto-covariance function could include points associated with positive numbers of whole pixels, and the first positive local maximum of the discrete auto-covariance function could be identified at one of the points. Sub-pixel estimation could also be performed using the point associated with the first positive local maximum and one or more neighboring points. Performing the sub-pixel estimation could include fitting a polynomial curve to the point associated with the first positive local maximum and the one or more neighboring points and identifying a number of whole and fractional pixels associated with a maximum of the polynomial curve.

Abstract: A method includes obtaining measurements associated with one or more controlled variables related to a structure of creped tissue paper during production of the creped tissue paper. The method also includes generating at least one control signal that adjusts one or more manipulated variables associated with the production of the creped tissue paper in order to alter the structure of the creped tissue paper. The one or more controlled variables include a number of folds per unit length of the creped tissue paper, a caliper of the creped tissue paper, a macro crepe of the creped tissue paper, and/or a micro crepe of the creped tissue paper. The manipulated variable(s) could include a crepe percentage, a creping blade angle, a flow of sizing agent, and/or a cross direction (CD) profile of nozzle positions associated with a spray boom that sprays sizing agent onto a Yankee dryer.

Abstract: A method includes receiving multiple biased measurements associated with a property of a sheet of material, where the biased measurements correspond to multiple known sheet geometries. The method also includes determining an unbiased measurement associated with the property of the sheet using the biased measurements, where the unbiased measurement corresponds to a nominal sheet geometry. The method further includes storing and/or outputting the unbiased measurement. Determining the unbiased measurement could include performing regression using the biased measurements and their corresponding sheet geometries to identify an estimated value of the property of the sheet at the nominal sheet geometry. The biased measurements can be generated using one or more sensors, and the sheet may not be stabilized during the biased measurement generation. Additional sheet geometries can also be created, such as by varying a tilt angle, a curvature, and/or a position of the sheet.

Abstract: Devices, systems and methods for determining capabilities of an on-line sensor are disclosed. The exemplary method may comprise the following acts. The method may generate an image of a sample texture with known characteristics. The method may transfer the image to an on-line sensor. The method may also analyze data generated by the on-line sensor to determine measured characteristics. The method may compare the measured characteristics to the known characteristics.

Abstract: An image-based measurement technique that directly measures the orientation of fibers in a moving web that comprises nonwoven material measures the orientation angles of the individual fibers so that a more robust estimate of the statistical distribution of fibers is obtained. The technique includes the steps of: (a) illuminating an area on at least one side of the web with radiation; (b) obtaining at least one digital image of the illuminated area; and (c) calculating the fiber orientation of the web by processing the at least one digital image with a gradient operator thereby analyzing the distribution of observed fiber orientation angles within the image. The gradient operator is preferably of a non-integer order between ? and ? and particularly between ¼ and ¾. The use of fractional-gradient operators yields more reliable results than when integer order gradients are employed.

Abstract: A method for fluidisation of a pulp flow in the headbox of a paper machine or such. The characteristics of the pulp flow are affected in the headbox's fluidiser (14) in one step only, whereby the height (h1) of the step is at least equal to the average fibre length, and after the fluidiser (14) the biggest permissible step expression in the flow channel in direction z is smaller than the average fibre length.

Abstract: The invention concerns a method for fluidisation of a pulp flow in the headbox of a paper machine or such. The characteristics of the pulp flow are affected in the headbox's fluidiser (14) in one step only, whereby the height (h1) of the step is at least equal to the average fibre length, and after the fluidiser (14) the biggest permissible step expansion in the flow channel in direction z is smaller than the average fibre length.