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Posted: March 4, 2008
Physicist earns patent for materials weakness detection system
(Nanowerk News) The first patent awarded to Southeastern Louisiana University through one of its faculty has the potential to identify weaknesses in structures ranging from massive bridge construction to the tiniest elements of nanotechnology no larger than a speck of dust on a pinhead.
The patent is for a deformation prediction instrument developed by physicist Sanichiro Yoshida. The instrument uses the technology of optical interferometry to make precise measurements that identify weak spots in a wide range of materials, including metals, plastics and other products.
Interferometry uses multiple light paths -- typically two -- from a common source, in this case a laser. The light paths allow the operator to exactly measure the difference in the path lengths when the light waves hit an object. The light waves – measuring less than one micron or one millionth of a meter – intersect on the material under study, are carefully measured and compared by the interferometer. This determines displacements of all points on the object, and through analysis of the pattern of the displacements, reveals a point of weakness in the material.
Yoshida, who has been working with light and lasers since1983 and optical interferometry since 1994, developed the mathematical procedure that determines the actual displacement from the interferometric images. He also has a second patent pending on a related development.
“This approach allows us to be able to predict where and when fractures may occur by determining the weak spot and the remaining intact life of the material,” Yoshida explained. “This has significant applications in engineering and construction technology where we could possibly do the measurements from a distance or using portable equipment.
“It also seems to work well with very small items, such as what we see in nanotechnology,” he added. “It is very hard to predict failure in small objects because the dynamics of the structures are very different, but this device seems to work with this.”
Yoshida, who also serves as a scientist at Livingston’s (LA) Laser Interferometer Gravitational Wave Observatory where researchers are probing Einstein’s theory of gravitational fluctuations, is currently trying to develop a partnership with a software firm as the next step in further developing and perfecting the instrument. In addition, he will be working this summer under an agreement with Pennsylvania State University on the nanotechnology aspect that will also allow the institutions to exchange students and faculty.
Before the break up of the Soviet Union, Yoshida worked in Siberia with Russian scientists, whom he says developed the theory his invention is based upon. The Russian scientists were using satellite technology to measure small changes in the earth’s crust as a way of possibly predicting earthquakes. Yoshida took that theory, introduced optical interferometry, and worked to make the theory a practical tool in modern applications.
Five undergraduate students work with Yoshida in his laboratory, carrying out various experiments under his direction. Two of those students, Christopher W. Schneider of Ponchatoula and John A. Gaffney of San Pedro Sula, Honduras, will present papers on their work at the American Physical Society’s annual meeting in New Orleans in March. Preliminary experiments conducted three years ago on the first version of the optical interferometer by Rashmi Manjegowda, a former Southeastern student from India helped Yoshida confirm the validity of the patented technology.