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Being Part of the Solution - Part 2: Guidance vs. Criticism, Solutions!, October 2001, Vol. 84(10)

Being part of the solution part 2: guidance vs. criticism, Solutions!, October 2001, Vol. 84(10)

ï¿ŒPractical Solutions: Vaccum Systems, Troubleshooting paper machine vacuum systems: Part I, vol. 01: no. 01 september 2001 SOLUTIONS! [01SEPSO90.pdf]

Troubleshooting paper machine vacuum systems: part I, Solutions!, September 2001, Vol. 1(1)

Being Part of the Solution - Part 1: Focusing on Other Peopleâ??s Needs, Solutions!, September 2001, Vol. 1(1)

Being part of the solution - part 1: focusing on other people’s needs, Solutions!, September 2001, Vol. 1(1)

Challenges and Solutions: The Tissue Industry in Europe, Tissue360º Spring/Summer 2023

Flow rheology of light foams generated from aqueous solutions of polyvinyl alcohol, TAPPI Journal January 2023

ABSTRACT: Recent studies have shown that foam-assisted application of additives into a wet web has advantages over the conventional way of adding the chemicals into the pulp suspension before forming, e.g., increased mechanical retention as well as high dosage giving increased wet strength without impairing the sheet uniformity. To engineer processes utilizing this new technology, the complex flow behavior of applied foams must be quantified. At the minimum, the foam viscosity and the slip velocity at the solid surfaces need to be known to build practical models that can be used in analyzing and upscaling unit processes of the foam-assisted application.In this study, the rheological behavior was quantified for foams having polyvinyl alcohol (PVOH), a widely used strength additive chemical, as the surfactant. The foam density was varied between 100 g/L and 300 g/L, and the concentration of the PVOH solution was varied between 0.5% and 6.0% (w/w). The foams were generated with a commercial foam generator, and the rheological properties of the foams were measured by using a horizontal pipe bank. At the outlet from the generator, the volumetric flow rate, the absolute pressure, and the bubble size distribution of the foam were measured. In the measurement pipe section, the viscous pressure gradient and the slip velocity were measured, after which the foam was discharged to ambient air pressure. The viscosity and the dynamic surface tension of the PVOH solutions were quantified with commercial laboratory devices. In the viscosity analysis, the apparent shear rate was calculated from the volumetric flow rate, and the resulting apparent viscosity was translated to real material viscosity data by applying the Weissenberg-Rabinowitsch correction. The results indicated that PVOH foams can be described with high accuracy as shear-thinning power-law fluids where the detailed behavior depends on the foam density and the PVOH concentration. Slip flow, as usual, increased with increasing wall shear stress, but it was also dependent on the PVOH concentration, the air content, and the bubble size. For both the foam viscosity and the slip flow, a correlation was found that described the quantitative behavior of all the studied foams with good accuracy.

Despite the Risks, Asia Presents a Tempting Treat, Solutions!, July 2003, Vol. 86(7)

Despite the risks, Asia presents a tempting treat, Solutions!, July 2003, Vol. 86(7) (310KB)

Process of Control: Using Process Dynamic Simulation, MAY 2003 SOLUTIONS! [03MAYSO36.pdf]

Using dynamic process simulation for business and risk management, Solutions!, May 2003, Vol. 86(5) (445KB)

Do you listen when your equipment speaks to you?, Solutions!, September 2003, Vol. 86(9)

Do you listen when your equipment speaks to you?, Solutions!, September 2003, Vol. 86(9) (232KB)

Oxygen delignification as a pretreatment for acetosolv pulps bleaching, Solutions!, February 2002, Vol. 85(2) (246KB)

Oxygen delignification as a pretreatment for acetosolv pulps bleaching, Solutions!, February 2002, Vol. 85(2) (246KB)

SPOTLIGHT ￌ: LONG TERM HOPEFULNESS, SOLUTIONS! January 2006 [05JANSO06.pdf]

Spotlight, Solutions!, January 2005, Vol. 88(1) (53KB)