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Inside Iowa State
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September 12, 2003

Research shorts

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 Croatian farmers.

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 power industry.

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.

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