Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
The Rate Of Fluid Absorption In Porous Media, Ran Wei Rioux
The Rate Of Fluid Absorption In Porous Media, Ran Wei Rioux
Electronic Theses and Dissertations
Fluid flow in porous media is an important process for many applications such as oil recovery, packed bed absorption colun~ns and filtration. Short time fluid uptake is important for processes such as textile sizing, paper coating and printing. But more work is needed to characterize the parameters that determine the absorption rate. This work is focused on short time absorption rate on uncoated and coated paper. Absorption rate is measured with a Bristow Wheel device for seven different uncoated papers and eleven coated papers. Gloss dynamics of freshly printed samples and tack dynamics are measured with two novel devices. Various …
Oxygen Delignification Kinetics And Selectivity Improvement, Steven M. Violette
Oxygen Delignification Kinetics And Selectivity Improvement, Steven M. Violette
Electronic Theses and Dissertations
Pulp strength loss during oxygen delignification is caused by cellulose chain cleavage resulting fiom attack by oxygen-based radicals generated through reactions with lignin. The objective of this research was to improve the lignin-to-cellulose selectivity during oxygen delignification by using radical-scavenging polymeric additives that adsorb on the cellulose surfaces where protection fiom radicals is needed. Among the polymers evaluated were starch, carboxymethyl-cellulose, galactomannan, xylan, and glucomannan. Oxygen delignification experiments were conducted on Northeast softwood Kraft pulps at different temperatures, sodium hydroxide charges, reaction times, and pretreatments. The effect of polymer additives on the selectivity and kinetics was studied. Polymer adsorption on …
Viscoelastic Roll Coating Flows, Mitchell A. Johnson
Viscoelastic Roll Coating Flows, Mitchell A. Johnson
Electronic Theses and Dissertations
The physics of a fluid flow between two rotating cylinders is important in processes such as bearing lubrication, roll coating, and printing. A small amount of dissolved polymer in the fluid can have a large impact on the behavior of the process. Viscoelasticity affects the stability of application and metering processes, and reduces the maximum speed at which a uniform film can be coated onto a substrate. The goal of this work is to characterize the effect of viscoelasticity on the forward roll coating operation. A bench-top apparatus simulated the process. Measurements of the gap between the roll surfaces, pressure …
Relationship Between Alkaline Pulp Yield And The Mass Fraction And Degree Of Polymerization Of Cellulose In Pulp, Mehmet Sefik Tunc
Relationship Between Alkaline Pulp Yield And The Mass Fraction And Degree Of Polymerization Of Cellulose In Pulp, Mehmet Sefik Tunc
Electronic Theses and Dissertations
Wood as a raw material is generally the dominant cost factor for the production of chemical pulp. Therefore, an increase in pulp yield has a major impact on the competitiveness of a mill. In order to optimize pulp yield, for example by changing operating conditions, a mill must be able to monitor the yield accurately. However, an accurate "real-time" pulp yield measurement method is not available at the present time. Pulping yield is presently measured from the amount of pulp produced from a given quantity of wood consumed over a 3 to 6 month time frame. This method is obviously …