Abstract: The invention relates to a method and arrangement for detecting free fiber ends in a paper surface. The method comprises illuminating a target sample (6) surface, which comprises free fiber ends, from at least two directions one at the time, with at least one light source (1). Original reflectance images are obtained for the target sample (6) surface with an imaging device (4), and a surface normal is estimated for each image pixel of the original reflectance image. Thus it is possible to reconstruct a reconstructed reflectance image from the estimated surface normals, and to compare the reconstructed reflectance image and the corresponding original reflectance image and to construct a difference image, where the differences represent shadow objects of the free fiber ends in a paper surface.

Abstract: The invention relates to a method for analysing a sample comprising at least a first and a second scale inhibitor, which scale inhibitors are synthetic organic compounds comprising at least one ionised group. The method comprises optionally diluting and/or purifying the sample, and allowing the sample interact with a reagent comprising lanthanide(III) ion. The sample is excited at a first excitation wavelength and a sample signal deriving from the lanthanide(III) ion is detected at a signal wavelength by using time-resolved luminescence measurement. The total concentration of the first and the second scale inhibitor is determined by using the detected sample signal, and the concentration of the first scale inhibitor in the sample is determined. The concentration of the second scale inhibitor is determined mathematically by using the obtained results for the total concentration and for the first scale inhibitor concentration.

Abstract: The invention relates to a method for preparing a dry cationic hydrogel polymer product. The method comprises polymerisation of a reaction mixture comprising ethylenically unsaturated monomers in presence of water and initiator(s) by radical polymerisation and obtaining a hydrogel polymer. The hydrogel polymer is comminuted by chopping or shredding, and dried, whereby a dry hydrogel polymer product in powder form is obtained. At least one cationic reverse phase emulsion polymer is added to the hydro polymer at the comminuting step. The invention relates also to a dry cationic hydrogel polymer composition prepared by the method and its use.

Abstract: The invention relates to a papermaking agent system in liquid form, which comprises (i) cationic starch solution, prepared by cooking a starch mixture comprising a starch component and a water component, and (ii) polymer composition, which has anionic and cationic groups and a cationic net charge of >0.1 meq/g. The polymer composition comprises or originates from at least one of constituents a), b) or c). Constituent a) contains an amphoteric polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic and cationic groups attached to the copolymer. Constituent b) contains a first polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic or cationic groups attached to the copolymer, as well as a second polymer, which comprises groups with opposite charge than the first polymer.

Abstract: The invention relates to a method for producing microfibrillated cellulose, where a suspension comprising cellulose derivative in a liquid phase which comprises an organic solvent is provided. The suspension of cellulose derivative is mechanically treated and microfibrillated cellulose is obtained. At least a part of the liquid phase from the microfibrillated cellulose is separated and microfibrillated cellulose with a dry solids content of >30 weight-% is obtained.

Abstract: Exemplary embodiments of the present disclosure include paper, methods of making paper, and the like.

Abstract: The invention relates to a composition for sizing of a surface of paper, board or the like and its use for increasing strength properties of paper, board or the like. The composition has a solids content of 3-30%, and it comprises degraded non-ion is starch, and at least 0.5 weight-% of anionic polyacrylamide, which has a molecular weight, MW, >500 000 g/mol and <2 500 000 g/mol and an anionicity in the range of 4-35 mol-%. The invention further relates also to a method for producing paper, board or the like, which comprises addition of a first strength composition, which comprises a cationic agent, to a fibre stock, formation of a fibrous web from the fibre stock, drying of the fibrous web to dryness of at least 60%, and application of a second strength com position, which comprises an anionic hydrophilic polymer and a starch component, on the surface of the fibrous web.

Abstract: An electrolyte membrane suitable for use in an electrochemical cell is described. It comprises a polymer electrolyte body and at least one metal oxide thin film layer on at least one surface of the polymer electrolyte body, wherein said metal oxide thin film layer is permeable to protons. Furthermore, the method for preparation and uses thereof are disclosed.

Abstract: Paper strength systems including polyamine-polyamidoamine-epihalohydrin (PPAE) resin are disclosed. Also disclosed are methods of forming a paper including applying a strength system comprising PPAE to cellulosic fiber, as well as the resultant paper.

Abstract: The invention relates to a method for nitrogen removal from aqueous medium, comprising steps of (a) converting NH4+ in the aqueous medium to NO2? by partial aerobic nitrification, (b) partially reducing the obtained NO2? to N2O in anoxic conditions, and (c) decomposing N2O to N2 with energy recovery. A mixture of ferrous sulfate and ferric sulfate is used in step (b) for reduction of NO2? to N2O.

Abstract: The invention relates to a strength agent for paper, board or the like. The strength agent comprises a first component, which is refined cellulosic fibres having a refining level of >70° SR, and a second component, which is a synthetic cationic polymer having a charge density of 0.1-2.5 meq/g, determined at pH 2.7, and an average molecular weight of >300 000 g/mol. The invention relates also to a use of the strength agent and to a method for increasing strength properties of paper, board or the like.

Abstract: The invention relates to a method for treating a fiber stock for making of paper, board or the like. The method comprises obtaining a fiber thick stock and adding to the fiber thick stock at least one cationic first agent, and adding separately to the fiber stock and after the addition of the cationic first agent, at least one anionic second agent, which is an water-soluble anionic copolymer of acrylamide, methacrylamide or acrylonitrile, in such amount that the ratio of the added absolute cationic charge to the added absolute anionic charge is from 1:0.1 to 1:0.95. The invention relates also to the product prepared by using a fiber stock, which is treated by using the method.

Abstract: The present invention relates to a method for producing a cationic polyvinyl amine based copolymer. The present invention further relates to a cationic polyvinyl amine based copolymer and use of the copolymer in paper industry as a strength agent, a retention agent and a drainage agent.

Abstract: Methods for removing one or more contaminants from an aqueous stream comprising: adding one or more hydraulic binders and one or more promoters to the aqueous stream, and separating the contaminants from the aqueous stream are provided. The methods may be used for removing contaminants that are arsenic-based, selenium-based, cadmium-based, zinc-based, mercury-based, iron-based, chromium-based and/or phosphate-based.

Abstract: The present invention provides a biocide composition comprising a biocide and a carrier, wherein the biocide is soluble in the carrier. The carrier may comprise polyethylene glycol ester. The present invention also provides a method for controlling biofilms by eliminating and/or preventing microorganisms in an aqueous environment.

Abstract: Methods of characterizing the topography of a surface of a creped material, devices for characterizing surface topography of a creped material, computer systems for characterizing surface topography of a creped material, and the like, are disclosed.

Abstract: The present invention provides a method for preventing or decreasing scale formation on process surfaces in manufacturing process of paper, board or the like, in which method performic acid is used as an antiscaling agent.

Abstract: The invention relates a method for producing a suspension of microfibrillated cellulose. The method comprises at least the steps of obtaining an aqueous suspension of natural cellulose fibres, adding an additive consisting of at least one natural polymer to the suspension of natural cellulose fibres, and feeding the obtained mixture comprising natural cellulose fibres and the additive into a homogenizer or a fluidizer. The invention relates also to a microfibrillated cellulose obtained by the method and its use.

Abstract: The invention relates to a method for improving rheological properties of an aqueous pigment slurry. In the method dispersion agent is added to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added. The dispersion agent comprises styrene acrylate copolymer. The invention relates also to dispersion agent for a pigment slurry comprising a first component comprising styrene acrylate copolymer and a second component comprising a conventional dispersion agent, such as a straight-chain polyacrylate.

Abstract: The invention relates to a method for improving rheological properties of an aqueous pigment slurry. In the method dispersion agent is added to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added. The dispersion agent comprises styrene acrylate copolymer. The invention also relates to a dispersion agent for a pigment slurry comprising a first component comprising styrene acrylate copolymer and a second component comprising a conventional dispersion agent, such as a straight-chain polyacrylate.