September 12, 2003
Help for Croatian farmers
Entomology professor Jon Tollefson is using his expertise in corn rootworm
to help Croatian farmers. He and a Croatian scientist are conducting a
two-year study to evaluate Croatian corn germplasm for rootworm resistance.
Farmers in northeast Croatia are experiencing losses of 50 to 60 percent.
Insecticide is the usual solution, but the cost is too high for most
On a recent trip to Croatia, Tollefson spread the message of crop rotation
among farmers. The Western corn rootworm lays its eggs each fall, and the
larvae hatch in the spring. Planting an alternate crop in the spring
literally can starve to death the new rootworms.
Disaster-proof power grids
The Aug. 14 outage that cut electricity in the East is an example of what
researchers on a three-year Iowa State project intend to prevent through
strategic planning of power system transmission control technologies and
related cost-recovery systems.
Professors James McCalley, Venkataramana Ajjarapu and Vijay Vittal, experts
in electric power engineering, are part of an inter-disciplinary team that
will develop a control design method to rapidly reconfigure power grids in
response to natural disasters, equipment failure and acts of sabotage that
affect the nation's electric transmission system.
Key to this work is designing hybrid controls, a combination of discrete
event network switches and continuous feedback voltage and frequency
controllers. Professors Ratnesh Kumar and Nicola Elia, control system
experts, will be involved in this part of the effort.
A third component, led by economics professor Oscar Volij, will examine
economic and social issues related to equitable cost recovery for financial
investments in transmission -- a problem intensified by the growing number
of transmission owners and users brought on by deregulation of the electric
Metals that bend
Under certain conditions, metals can take on glass-like properties. Ames
Laboratory researchers Dan Sordelet and Matt Kramer want to find out why --
and what takes place.
Normally, metals have a very regular (periodic) structure in which atoms
align. However, the glass form of crystalline metals is amorphous (it lacks
that regular pattern to its atomic structure), making it both hard and
elastic. It will snap back to its original shape if it's not bent too far.
To get an idea of how the atoms are arranged, the two work "back-wards,"
through a process called devitrification. It involves gradually heating
metallic glass until it loses its amorphous properties and the atoms realign
in the metal's regular crystalline pattern.
A practical application from the research is controlling devitrification,
one of the keys to forming nanoscale materials.
Ames, Iowa 50011, (515) 294-4111
Published by: University Relations,
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