BiodegradablePlasticUtensils1
Autor:
Scott Bauer
Credit:
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).
Krótki link:
źródło:
Wymiary:
2700 x 1757 Pixel (572440 Bytes)
Opis:
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.
Licencja:
Public domain
Komentarz do licencji:
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.
Więcej informacji o licencji można znaleźć tutaj. Ostatnia aktualizacja: Sat, 20 Aug 2022 23:49:13 GMT