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Journal articles
Open Access
Prediction of residual calcium carbonate (CaCO3) in the lime

ABSTRACT: In a kraft pulp mill, the rotary lime kiln is responsible for converting calcium carbonate (CaCO3) into calcium oxide (CaO) to be reused in the causticizing plant. An important parameter of the calcination efficiency and the product quality is the amount of CaCO3 not converted to CaO, commonly defined as residual carbonate. This parameter is usually determined through laboratory analysis, which introduces delays in process control and limits the ability to make timely operational adjustments. This work presents a predictive model that functions as a soft sensor for the residual carbonate in a lime kiln of a Brazilian kraft pulp mill. This model was able to estimate residual CaCO3 every 30 min using routinely measured online process variables, which is a considerable reduction from the 6-h average laboratory measurement. The correlation coefficient (r) between the model predictions and the mill values was 0.83, with a mean absolute error (MAE) of 0.33%. Considering the effect of the residence time throughout the lime kiln proved to be decisive in obtaining a satisfactory prediction result. After model validation, a variable importance analysis showed that the carbon monoxide (CO) concentration in the stack flue gas (in ppm), secondary air temperature (in oC), and fan speed (in %) were the most influential variables in predicting the residual carbonate content. Combined with commonly used operation expertise, this subset of variables can serve as additional information to achieve smoother lime kiln operation.

Journal articles
Magazine articles
Open Access
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
Open Access
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.

Journal articles
Magazine articles
Open Access
Multifunctional starch-based barrier materials, TAPPI Journal August 2021

ABSTRACT: Natural and renewable polymer-based barrier materials play an inevitable role in a sustainable economy. Most commercially available barrier materials are either based on multiple layers of synthetic polymers or petroleum-based chemicals. Tremendous amounts of research are being done in academia and industry to replace these synthetic barrier materials with natural and environmentally friendly materials. The current work summarizes the application of starch-based materials for various barrier applications, such as water vapor, oxygen, liquid water, oil, and grease. Also, exotic starch-based barrier materials for the application of sound, ultraviolet, and thermal barrier applications are reviewed. The potential of starch-based materials to offer antimicrobial and antiviral properties is discussed. Finally, commercially available starch-based barrier materials have been summarized.

Journal articles
Open Access
Setting the Scene for Environmental Compliance in the Last D

Setting the Scene for Environmental Compliance in the Last Decade of the Twentieth Century, 1990 Nonwovens Conference Proceedings

Journal articles
Monitoring mechanical seal performance to reduce fixed costs

Monitoring mechanical seal performance to reduce fixed costs, Solutions! Online Exclusives, June 2003

Journal articles
Open Access
Hot Soft Calendering: Effect on Surface Finish and Printabil

Hot Soft Calendering: Effect on Surface Finish and Printability of Paper, 1990 International Printing & Graphic Arts Conference Proceedings

Journal articles
Open Access
Combining Charge Distributions and Heats of Interaction to P

Combining Charge Distributions and Heats of Interaction to Probe Filled Papermaking Furnish Flocculation Mechanisms, 1993 Papermakers Conference Proceedings

Journal articles
Open Access
AOX Content of Paper Manufactured with 'Chlorine Free' Pulps

AOX Content of Paper Manufactured with 'Chlorine Free' Pulps, 1995 Papermakers Conference Proceedings

Journal articles
Rheological Indicators to Predict the Extrusion Coating Performance of LDPE, 2004 PLACE Conference

Rheological Indicators to Predict the Extrusion Coating Performance of LDPE, 2004 PLACE Conference

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