Abstract: A method and apparatus for determining and controlling a property of colloidal substances that undergo at least one of a temperature dependent phase transition and a temperature dependent adsorption-desorption process is disclosed. The colloidal particles are characterized by performing successive measurements of light attenuation or emission by a colloidal mixture at two or more temperatures and at one or more wavelength. The difference or ratio of the measurements at two or more temperatures provides a measure of the colloidal stability with respect to temperature. The amount of certain organic colloids that are unstable to temperature variation may be determined from the magnitude of the measurement change. This method may be specifically applied to determining the tackiness and propensity to deposit of colloidal pitch or wood resin in pulp or paper process water as an indication of the effectiveness of a chemical control program.

Abstract: A method and apparatus for determining and controlling a property of colloidal substances that undergo at least one of a temperature dependent phase transition and a temperature dependent adsorption-desorption process is disclosed. The colloidal particles are characterized by performing successive measurements of light attenuation or emission by a colloidal mixture at two or more temperatures and at one or more wavelength. The difference or ratio of the measurements at two or more temperatures provides a measure of the colloidal stability with respect to temperature. The amount of certain organic colloids that are unstable to temperature variation may be determined from the magnitude of the measurement change. This method may be specifically applied to determining the tackiness and propensity to deposit of colloidal pitch or wood resin in pulp or paper process water as an indication of the effectiveness of a chemical control program.

Abstract: On-line measurements of an amount of dissolved solids in a liquid sample are determined by using both conductivity and UV measurements. More particularly, an amount of dissolved solids in a pulp and paper mill process water or effluent is determined by irradiating at least a portion of a liquid sample with ultraviolet light and subsequently measuring an absorption of the light by the liquid sample. Furthermore the conductivity of the liquid sample is measured and subsequently a computation is from a first relationship between the measured absorption of the first wavelength by the liquid sample and the measured conductivity of the liquid sample using a suitably programmed processor.