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Kraft pulp viscosity as a predictor of paper strength: Its uses and abuses, TAPPI Journal October 2023

ABSTRACT: For bleached kraft pulps, two factors govern paper strength: the individual fiber strength, and the bond strength that adheres the individual fibers together in the paper matrix. Inherent fiber strength is related to the length of the carbohydrate polymers, also known as the degree of polymerization (DP). Average DP (DP) is inferred by performing pulp viscosity measurements. Under certain circumstances during kraft pulping and bleaching, the average polymer lengths can be shortened, resulting in lower pulp viscosity, and may indicate fiber damage. Fiber damage typically manifests itself as a reduction in tear strength for well-bonded handsheets.This paper will review the literature on how pulp viscosity can predict paper/fiber strength and how it can be used as a diagnostic tool. It can be a means to monitor pulp quality during pulping and bleaching, as well as to alert when such operations approach a critical threshold. However, viscosity losses must be carefully and judiciously analyzed. Like most diagnostic tools, viscosity measurements can be misused and abused, which can lead to incorrect inferences about intrinsic fiber strength. This review will also cover these misuses. The overall goal is to provide the papermaker a better understanding of what pulp viscosity is, how it correlates to potential sheet strength, and what its limitations are. It will be illustrated that when pulp viscosity drops below a critical value, it will indicate an appreciable deterioration in the paper’s tear and tensile strength.

Filtration efficiency and breathability of selected face masks, TAPPI Journal September 2023

ABSTRACT: Face masks have been used as physical barriers to stop respiratory infections for many years. Due to insufficient and low supply of certified masks, alternative face covers such as face shields, neck gaiters, and fabric reusable masks gained attention during the COVID-19 pandemic. However, for these alternate face masks to fulfill their intended function, they must be effective. Additionally, the level of breathability provided by the makeshift masks must be at a certain level. The work reported in this paper was carried out to determine the relationship between filtration efficiency (FE), breathability, and important physical characteristics of mask substrates. The fiber diameter of the core filter layer was determined using a scanning electron microscope. Five types of face masks (two types of N95, two types of surgical masks, and a 100% knitted cotton fabric) were tested for their FE and breathability using moisture vapor transmission rate (MVTR). The cotton knitted mask had the lowest FE (5.10%•26.47%), while the National Institute for Occupational Safety and Health (NIOSH)-certified N95 mask had the highest FE values (92.10%•99.65%). However, the cotton mask outperformed the N95 in terms of the pressure drop, meaning higher comfort. In general, the N95 face mask provided the best protection against aerosolized particles. According to the regression analysis, the fiber diameter of the mask filter substrate serves as an important predictor of FE of mask substrates. In this study, it was confirmed that fiber diameter is inversely related to the filtration ability. Results show that compact structure with finer fibers will enable higher filtration efficiency. The study lends itself to developing layered face masks to obtain optimum filters with good filtration, better fit, and acceptable comfort for the wearer.

ABB’s New R&D Center: Perfect Location for the Transformation of the Pulp and Paper Industry, Paper360º September/October 2023

Characterization of hard scale formed in the kraft mill green liquor processing equipment, TAPPI JOURNAL January 2013

Characterization of hard scale formed in the kraft mill green liquor processing equipment, TAPPI JOURNAL January 2013

TAPPI JOURNAL Summaries, Paper360° July/August 2013

TAPPI JOURNAL Summaries, Paper360º July/August 2013

Effectiveness of magnesium oxide additives in mitigating fouling problems in kraft recovery boilers, TAPPI JOURNAL June 2013

Effectiveness of magnesium oxide additives in mitigating fouling problems in kraft recovery boilers, TAPPI JOURNAL June 2013

Effect of carboxymethylcellulose and starch depressants on recovery of filler and fines in tertiary flotation, TAPPI JOURNAL March 2013

Effect of carboxymethylcellulose and starch depressants on recovery of filler and fines in tertiary flotation, TAPPI JOURNAL March 2013

Best Practices in Maintenance and Reliability, Paper360° March/April 2013

Best Practices in Maintenance and Reliability, Paper360º March/April 2013

TAPPI JOURNAL Summaries, Paper360° March/April 2013

TAPPI JOURNAL Summaries, Paper360º March/April 2013

Setpoint: Recognize and Protect Your Assets, Paper360° May/June 2013

SetPoint: Recognize and Protect Your Assets, Paper360º May/June 2013