Victoria,
B.C. -- September 12, 2002 -- Drs. Dionissios T.
Hristopulos, and Tetsu Uesaka, have been awarded
the 2003 Van den Akker Prize for Paper Physics.
Their paper, “A Model of Machine-Direction
Tesion Variations in Paper Webs with Runnability
Applications”, in the Journal of Pulp and
Paper Science, December 2002, has been selected
by an international panel of judges as the greatest
contribution to the field of paper physics this
year.
In the winning
paper, Hristopulos, and Uesaka helped to identify
critical parameters for paper breaks and factors
that control the strength reliability of paper
products. They did this by developing a model
of web dynamics to investigate tension variations,
which play a major role in runnability and paper
breaks. The model predicts abrupt changes in
the web speed and tension at contact points where
external forces are applied, high strain rates
at nip contacts, and tension surges during start-up,
as observed in many pressrooms. Their research
determined that the mechanical draw is an accurate
estimate of the strain increment for time-independent,
but not fluctuating, web speeds.
Hristopulos,
and Uesaka also investigated the impact of out-of-round
rolls on runnability by coupling the web dynamics
model to a weak-link model of web failure. They
found that, for moderate roll deformations, the
out-of-roundness contributes statistically to
the increase in break frequency. The risk of
web breaks is significant for extreme deformations,
especially when a new roll begins unwinding.
Dr. Hristopulos
is an Associate Professor in the Department of
Mineral Resources Engineering at the Technical
University of Crete. His previous position was
as a Research Scientist at the Pulp and Paper
Research Institute of Canada (PAPRICAN). At PAPRICAN
he was a member of the Product Performance Program
and specialized on statistical models of paper
structure and the fracture mechanics of heterogeneous
fibre materials.
Dr. Tetsu
Uesaka is currently a Program Manager in the
Product Performance Program at PAPRICAN.
The Johannes
A. Van den Akker Prize for Advances in Paper
Physics was created to recognize the best contribution
made to the field of paper physics and to the
paper industry each year. Dr. Van den Akker was
known for his brilliant mind, demand for excellence,
and leadership in the field of paper physics
for over 40 years.
The Johannes
A. Van den Akker Prize for Advances in Paper
Physics was established in 1999 by IPST, with
an endowment made possible through the generous
donations of the family, friends, and students
of Dr. Van den Akker, a former senior research
associate and Chairman of the Department of Physics
and Mathematics at the Institute of Paper Chemistry
(IPC). The Van den Akker Prize is awarded annually
through the Technical Association of the Pulp
and Paper Industry (TAPPI) Paper Physics Committee,
of which Dr. Van den Akker was a member for many
years.
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