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Magazine articles
The effect of contact time between CPAM and colloidal silica on the flocculation behavior in the approach flow, TAPPI Journal January 2021
ABSTRACT: Multicomponent wet-end systems have become increasingly common in papermaking, with the objective of improving the retention-formation-dewatering relationship. It is quite common to use at least a cationic polymer, often in combination with an anionic microparticle. In some cases, a fixative is also used. However, there is still debate on the optimal implementation of these systems. In particular, optimizing the contact time of the cationic polymer prior to addition of the anionic microparticle is still poorly understood. In this work, we investigate the effect of the contact time of a cationic polyacrylamide (CPAM) prior to addition of colloidal silica on the flocculation response in a flowing fiber suspension. The effect of using a fixative is also investigated. Focused beam reflectance measurements (FBRM) are combined with zeta-potential measurements for optimizing the addition levels of a two- and three-component system, as well as for elucidating the effect of contact time on CPAM performance. Trials are then performed on a pilot scale flow loop, where the time between addition of these two components is varied and the resulting flocculation response is characterized using high-speed filming and image analysis techniques. It is shown that the efficacy of CPAM can be improved through use of a fixative and that a longer CPAM contact time may be beneficial in terms of immediate flocculation; however, hydrodynamic shear tends to dominate the flocculation response regardless of contact time due to floc rupture.
Journal articles
Magazine articles
Application of fuzzy TOPSIS in the Analyze phase of the DMAIC cycle to aid decision-making, TAPPI Journal April 2020
ABSTRACT: This paper reports the use of multicriteria analysis in the Analyze phase of the DMAIC (Define-Measure-Analyze-Improve-Control) cycle for continuous improvement. The research was carried out in a tissue paper factory located in southern Brazil. A sample of 64 parts of 16 different reels of recycled paper was used. A problem regarding paper quality variability was detected, presenting a scrap index ranging between 9% and 23%, compromising machine productivity and product sales. This motivated the implementation of a structured project supported by the application of the DMAIC cycle. The project team (machine operators, maintenance staff, supervisor, and data analyst) defined the evaluation criteria and determined the control intervals and their equivalence with linguistic variables to support the necessary evaluations for the application of fuzzy TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution). The criteria were C1-Longitudinal Strength (Kgf), C2-Longitudinal Elongation (mm), C3-Cross-strength (kgf), C4-Cross-elongation (mm), C5-Weight (g/m²), and C6-Humidity (%). The results showed that samples with the same ranking had the lowest scrap indexes in the subsequent process. Also, the criterion C5 had a more significant impact on the quality of the product than the other criteria, which was determined from the DMAIC sequence. Improvements related to C5 should be prioritized. The fuzzy TOPSIS method presented is a flexible tool, adapting itself to the solution of the problem and contributing to the decision-making process.
Magazine articles
Leading the giant: an interview with john t. dillon, ceo and president, international paper, TAPPI JOURNAL, June 1998, Vol. 81(6)
Leading the giant: an interview with john t. dillon, ceo and president, international paper, TAPPI JOURNAL, June 1998, Vol. 81(6)
Magazine articles
English as a first and second language - part 7: a strategy for spelling, TAPPI JOURNAL, October 1998, Vol.81(10)
English as a first and second language - part 7: a strategy for spelling, TAPPI JOURNAL, October 1998, Vol.81(10)
Magazine articles
Technology spotlight - the tradeoffs: finishers and converters encounter speed, TAPPI JOURNAL, October 1998, Vol.81(10)
Technology spotlight - the tradeoffs: finishers and converters encounter speed, TAPPI JOURNAL, October 1998, Vol.81(10)
Magazine articles
The industry: beyond 2000, TAPPI JOURNAL, October 1998, Vol.81(10)
The industry: beyond 2000, TAPPI JOURNAL, October 1998, Vol.81(10)
Magazine articles
Indonesian update: a country in change, an industry in recovery, TAPPI JOURNAL, September 1998, Vol. 81(9)
Indonesian update: a country in change, an industry in recovery, TAPPI JOURNAL, September 1998, Vol. 81(9)
Magazine articles
An overview of the south african pulp and paper industry, TAPPI JOURNAL, April 1999, Vol. 82(4)
An overview of the south african pulp and paper industry, TAPPI JOURNAL, April 1999, Vol. 82(4)
Magazine articles
Retention aids for highspeed paper machines, TAPPI JOURNAL, April 1999, Vol. 82(4)
Retention aids for highspeed paper machines, TAPPI JOURNAL, April 1999, Vol. 82(4)
Magazine articles
Good manufacturing practices in recycled paper and paperboard production for use in food packaging, TAPPI JOURNAL, August 1999, Vol. 82(8)
Good manufacturing practices in recycled paper and paperboard production for use in food packaging, TAPPI JOURNAL, August 1999, Vol. 82(8)