Sunday, August 19, 2007

The division of waters (1925). Woodcut.

One of Escher's earlier works (part of the "Seven days of creation" series). I really like it for its stunning representation of volume, especially considering the technique used. It's a woodcut printed in black ink, so there are no shades, only black and white. It's pretty amazing...

Day and night (1938). Woodcut in black and grey (two blocks).

Hydrodynamic effects in non-newtonian fluides.

A non-Newtonian fluid is a fluid in which the viscosity changes with the applied strain rate.

This gives rise to several interesting effects. The Barus effect:

The Weissenberg effect:

And my personal favorite, Kaye effect. The video is really well made, and it even demonstrates a steady-state (continuous) version of Kaye effect:

Saturday, August 11, 2007

Benzene as a dienofile.

The only known example of benzene acting as a dienofile:"Perspective on Fluorocarbon Chemistry", D.M. Lemal, JOC 2004, 69(1), 1. It's a really good introductory article for anybody interested in fluoroorganic chemistry.

Friday, August 10, 2007

Reptiles, 1943 (lithograph). M. C. Escher.

Andrew's Glacier Cirque, RMNP.

I wonder if there is a route following this ridge line:And another one:

Spotting the fake smile.

Here is a really interesting test by BBC. After you get through all the smiles, it gives some pretty interesting info on distinguishing genuine and fake smiles (with videos).

SF6 (Xe?) and Archimedes.

A pretty cool twist on Archimedes:

I wonder what gas they use, it's too bad they don't say...