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Mill experience of calcium carbonate scale formation in green liquor pipelines, TAPPI Journal August 2020
ABSTRACT: Experience of hard calcite (CaCO3) scale formation in green liquor pipelines at four kraft pulp mills was systematically investigated to determine if there is any correlation between the severity of the scaling problem at each mill and the design and operating conditions of its causticizing plant. The results show that the high degree of supersaturation of calcium ions (Ca2+) in the liquor is the main contributing factor. Mills that operate at a lower green liquor total titratable alkali (TTA), higher causticity, and a larger liquor temperature drop are more likely to produce a green liquor that is supersaturated with Ca2+, and thus experience more severe scaling problems. In order to minimize CaCO3 scaling, the green liquor handling equipment should be operated as steady as possible to avoid conditions that allow Ca2+ to be supersaturated. The strategies include minimizing variations in liquor TTA, insulating the green liquor pipelines to reduce temperature gradients, and adding lime mud to weak wash to provide seeds for precipitation to occur on mud particles instead of on metal substrate.
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Standards
On-machine visible dirt measurement on moving sheets and the relationships to standard laboratory methods, TAPPI Journal August 2020
ABSTRACT: There has been a proliferation of new sensors to measure on-machine dirt specks that employ different technologies and methodologies to perform measurements. The differences in the on-machine technologies are discussed in terms of the TAPPI and ISO standard laboratory test methods with respect to dirt detection using light reflected from, or light transmitted through, the sheet. Also discussed are the requirements for measuring sta-tistically representative areas of the sheet; the difference between the dirt physical size and Equivalent Black Area (EBA) size; and the implication of these issues when specifying cleanliness acceptance criteria.This technical brief describes on-machine visible dirt measurement’s relationship to standard laboratory testing.
Journal articles
Magazine articles
Standards
Relating bending stiffness measurements across various free span lengths, TAPPI Journal August 2020
ABSTRACT: Bending stiffness should be an intrinsic property of a material, so it is puzzling that the TAPPI Standard Test Method T 836 “Bending stiffness, four point method” specifies span lengths when testing different types of corrugated fiberboard. These specified spans often limit the samples that can be measured with this method. To better understand the relationship between bending stiffness and span length, we performed measurements on a range of materials at different spans. The results provide a practical tool enabling comparison of bending stiffness measurements made at various span lengths. Additionally, this note discusses several areas that could serve as the foundation for more fundamental work exploring the bending behavior of corrugated board.
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Editorial: Kathleen Bennett: Opportunities for paper are pro
Editorial: Kathleen Bennett: Opportunities for paper are proliferating, TAPPI JOURNAL May 2016
Journal articles
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Combustion behavior of kraft black liquor droplets from hot
Combustion behavior of kraft black liquor droplets from hot water pretreated hardwood and softwood chips, November 2016 TAPPI JOURNAL
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Novel CaCO3-polymer nanocomposite fillers for the improvemen
Novel CaCO3-polymer nanocomposite fillers for the improvement of bagasse-based papers, November 2016 TAPPI JOURNAL
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Guest Editorial: Recognizing excellence in recycling, TAPPI
Guest Editorial: Recognizing excellence in recycling, TAPPI JOURNAL February 2012
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Editor's Note: An Ideal Raw Material for Pulp and Paper, TAP
Editor's Note: An Ideal Raw Material for Pulp and Paper, TAPPI JOURNAL March 2010
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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.
Journal articles
Magazine articles
Guest Editorial: Still working (overtime): Life-saving nonwovens and continued innovation, TAPPI Journal August 2021
ABSTRACT: Recently, the United States federal government has recommended the need for a booster shot to combat COVID-19, highlighting the highly contagious nature of its Delta variant. This variant is surging in countries as far apart as Thailand, Brazil, and the United States. While the availability of the vaccine is not an issue in the United States, African, Latin American, and South Asian countries are in dire need of the vaccine. This scenario necessitates the need for continued safety measures. Among the recommended safety measures, use of face masks has been proven to be effective. Recent analysis showed that two-thirds of the 32 states in the United States with face mask mandates found them helpful for lowering infection rates.