System and method for obtaining wide screen Schlieren photographs

A system for use in Schlieren photography includes (1) a viewing screen adjacently related to a large grating; (2) a small grating disposed in spaced relation with the large grating; (3) a transparent retainer for confining a transparent medium between the gratings; and (4) optics for imaging the small grating on the large grating. A light source and optically aligned lens are used to project a beam of light along axes extending through the small grating and strike the large grating, subsequent to passing through the medium. A Schlieren image of striations resulting from distortions of light rays proposed by the medium are formed on the screen. A camera is used to photograph the Schlieren image projected on the large screen

A Conformal Field Theory of Extrinsic Geometry of 2-d Surfaces

In the description of the extrinsic geometry of the string world sheet regarded as a conformal immersion of a 2-d surface in $R^3$, it was previously shown that, restricting to surfaces with $h\surd{g}\ =\ 1$, where $h$ is the mean scalar curvature and $g$ is the determinant of the induced metric on the surface, leads to Virasaro symmetry. An explicit form of the effective action on such surfaces is constructed in this article which is the extrinsic curvature analog of the WZNW action. This action turns out to be the gauge invariant combination of the actions encountered in 2-d intrinsic gravity theory in light-cone gauge and the geometric action appearing in the quantization of the Virasaro group. This action, besides exhibiting Virasaro symmetry in $z$-sector, has $SL(2,C)$ conserved currents in the $\bar{z}$-sector. This allows us to quantize this theory in the $\bar{z}$-sector along the lines of the WZNW model. The quantum theory on $h\surd{g}\ =\ 1$ surfaces in $R^3$ is shown to be in the same universality class as the intrinsic 2-d gravity theory.Comment: 30 page