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LA=lJF? = -89-4188 ...

decisions that are made every day by policymakers, land planners, and resource managers.Much of the work that we do is in partnership with others. We are at work with more than 1 ,200 State, local, and other Federal agencies in all 50 States to provide the earth science information that touches and serves the lives of every citizen every day. These partnerships produce savings to the taxpayer by avoiding duplicate efforts and by providing consistent science that can be reused tomorrow. Many of these partners have been with us for many years and share with us in the funding of programs and investigations that benefit State and local interest as well as adding to the national interest by providing information for the public good, as our mission mandates. These partnerships allow us constantly to test our science in the real world.Our work is also international in scope, reaching out to many nations with whom we share common concerns and similar geology and hydrology. International cooperation is more than just being a good neighbor. As scientists, we benefit immeasurably from the exchange of information with colleagues in other countries and learn more in the process about the resources, hazards, and environmental issues of our own country. Little is known, for example, about the transport and release of mercury or about the processes that control its fate in the environment. Cooperative mineral resource studies with the U.S. Forest Service in Venezuela are providing USGS scientists with information that will help in developing remediation efforts worldwide (see p. 88).I hope that you will find the new look of the Yearbook and the new vision of the U.S. Geological Survey to be positive changes that ensure we are continuing our commitment to provide "Earth

The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction in the only technique that can make nondestructive measurements in the interior of components. By recording the change in crystalline lattice spacings, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all lattice reflections are recorded in each measurement, which allows for easy examination of heterogeneous materials such as metal matrix composites. Measurements made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) demonstrate the potential at pulsed sources for in-situ stress measurements at ambient and elevated temperatures.

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