BiodegradablePlasticUtensils1
Forfatter/Opretter:
Scott Bauer
Kredit:
This image was released by the Agricultural Research Service, the research agency of the United States Department of Agriculture, with the ID k7245-1 (next).
Shortlink:
kilde:
størrelse:
2700 x 1757 Pixel (572440 Bytes)
beskrivelse:
Knives, forks, and spoons made from a biodegradable starch-polyester material.
The photo has been realized using the photoelasticity method, an experimental method which gets a fairly accurate picture of stress distribution even around abrupt discontinuities in a material.
When a ray of plane polarised light is passed through a photoelastic material, it gets resolved along the two principal stress directions and each of these components experiences different refractive indices. The difference in the refractive indices leads to a relative phase retardation between the two component waves.
The setup used to photograph this photo was probably composed of:
- A regular light source, with a quarter-wave plate installed to polarize the emerging light
- A regular photo camera, with a quarter-wave plate installed in front of the lens
Light and camera being installed and oriented in the same direction, the two
quarter-wave plates were turned with the polarizing axis in the same direction.
Licens:
Public domain
Kommentar på licensen:
This image or file is a work of a United States Department of Agriculture employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, the image is in the public domain.
Yderligere oplysninger om licens til billedet kan findes her. Sidste ændring: Sun, 24 Mar 2024 15:07:15 GMT
