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Magazine articles
Commercially relevant water vapor barrier properties of high amylose starch acetates: Fact or fiction?, TAPPI Journal September 2021
ABSTRACT: Starches have recently regained attention as ecofriendly barrier materials due to the increased demand for sustainable packaging. They are easily processable by conventional plastics processing equipment and have been utilized for oil and grease barrier applications. While starches have excellent oxygen barrier properties and decent water barrier properties at low relative humidity (RH), they are moisture sensitive, as demonstrated by the deterioration of the barrier properties at higher RH values. Starch esters are chemically modified starches where the hydroxyl group of the starch has been substituted by other moieties such as acetates. This imparts hydrophobicity to starches and has been claimed as a good way of retaining water vapor barrier properties of starches, even at high RH conditions. We studied the water vapor barrier properties of one class of starch esters, i.e., high amylose starch acetates that were assumed to have good water vapor barrier properties. Our investigations found that with a high degree of substitution of hydroxyl groups, the modified starches did indeed show improvements in water vapor response as compared to pure high amylose starch films; however, the barrier properties were orders of magnitude lower than commercially used water vapor barriers like polyethylene. Even though these materials had improved water vapor barrier response, high amylose starch acetates are likely unsuitable as water vapor barriers by themselves, as implied by previous literature studies and patents.
Magazine articles
Recycling 'low value' post-consumer fibers to improve quality and reduce costs, TAPPI JOURNAL, September 1997, Vol. 80(9)
Recycling 'low value' post-consumer fibers to improve quality and reduce costs, TAPPI JOURNAL, September 1997, Vol. 80(9)
Journal articles
Magazine articles
Viscoelastic web curl due to storage in wound rolls, TAPPI Journal July 2020
ABSTRACT: Winding is often the final operation in a roll-to-roll manufacturing process. Web materials, i.e., materials that are thin compared to their length, are wound into rolls because this form is the only practical means to store them. The resulting bending strains and associated stresses are large for thick webs and laminates. As many webs are viscoelastic on some time scale, bending stresses lead to creep and inhomogeneous changes in length. When the web material is unwound and cut into discrete samples, a residual curvature remains. This curvature, called curl, is the inability for the web to lie flat at no tension. Curl is an undesirable web defect that causes loss of productivity in a subsequent web process. This paper describes the development and implementation of modeling and experimental tools to explore and mitigate curl in homogenous webs. Two theoretical and numerical methods that allow the prediction of curl in a web are developed: a winding software based on bending recovery theory, and the implementation of dynamic simula-tions of winding. One experimental method is developed that directly measures the curl online by taking advantage of the anticlastic bending resulting from the curl. These methods are demonstrated for a low-density polyethylene web.
Journal articles
Magazine articles
Case study: Paper mill power plant optimization—balancing steam venting with mill demand, TAPPI Journal June 2020
ABSTRACT: Most Power departments are tasked with generating steam to support mill wide operations, generate electricity, and reduce operating costs. To accomplish these tasks, power boilers generate high pressure steam that is reduced to intermediate and low pressures for process utilization in the mill by means of steam turbine generator extraction or pressure reducing valves. The most economical method to reduce steam pressure is the use of steam turbine generators, as electricity is generated from the steam when it is reduced in pressure. Electricity that is produced by these generators provides a substantial financial benefit and helps offset overall operational costs. To achieve tangible financial gains, the mill must evaluate the overall cost of steam production and the price of electricity.The current work provides a case study of power plant optimization that evaluated electricity production and steam production costs balanced with mill steam demand. Process and cost optimization led to a significant reduc-tion in low pressure steam venting, resulting in reduced fuel consumption and reduced operating cost.
Magazine articles
A visit to mount st. helens; meta lake illustrates natural recovery following volcanic eruption, TAPPI JOURNAL, April 1994, Vol. 77(4)
A visit to mount st. helens; meta lake illustrates natural recovery following volcanic eruption, TAPPI JOURNAL, April 1994, Vol. 77(4)
Magazine articles
Hot-melt adhesive development and the proliferation of raw materials, TAPPI JOURNAL, September 1991, Vol. 74(9)
Hot-melt adhesive development and the proliferation of raw materials, TAPPI JOURNAL, September 1991, Vol. 74(9)
Magazine articles
Alberta newsprint and alberta research council bring deinking pilot plant on-stream, TAPPI JOURNAL, December 1992, Vol. 75(12)
Alberta newsprint and alberta research council bring deinking pilot plant on-stream, TAPPI JOURNAL, December 1992, Vol. 75(12)
Magazine articles
A waste management program for paper mill sludge high in ash, TAPPI JOURNAL, April 1990, Vol. 73(4)
A waste management program for paper mill sludge high in ash, TAPPI JOURNAL, April 1990, Vol. 73(4)
Magazine articles
1995 TAPPI foundation/af&pa conference: paper industry research challenges, TAPPI JOURNAL, April 1996, Vol. 79(4)
1995 TAPPI foundation/af&pa conference: paper industry research challenges, TAPPI JOURNAL, April 1996, Vol. 79(4)
Magazine articles
Catastrophic failure of cast iron dryer roll caused by severe erosion resulting from spoiler bar failures, TAPPI JOURNAL, April 1996, Vol. 79(4)
Catastrophic failure of cast iron dryer roll caused by severe erosion resulting from spoiler bar failures, TAPPI JOURNAL, April 1996, Vol. 79(4)