Slashdot Mirror


User: Swaf

Swaf's activity in the archive.

Stories
0
Comments
2
First seen
Last seen
Profile
(view on slashdot.org)

Comments · 2

  1. Re:Fuck off you americans on Atlas V's Maiden Launch a Success · · Score: 1, Flamebait

    Whithout being rude (but Monty Pythons are never rude anyway), it is true that this launch is badly resented by many Europeans. Don't forget that this project was heavily supported by the Defense Department. In current times of crisis when less commercial sats are produced, the army will still pay to get its own satellites launched. Add to that, a.o., the refusal of the Kyoto protocol, the arbitrary anti-freetrade measures against European steel and the alleged spying of economic data using Echelon (and I am not paranoid), and you will start to understand a growing state of mind in Europe towards the States. Not speaking about the militaristic views of Bush Jr... (I don't want to be classified as 'flamebait' ;-))

  2. Re:Transparent aluminum on Transparent Concrete · · Score: 1

    An intuitive (?) way to see things is that in metals the electromagnetic fields will induce currents that dissipate and reflect the energy of the wave. If I remember well, Maxwell equations actually requires 1) the conservation of the parallel (to the material surface) components of the electric field and 2) the electric field in an ideal conductor to be exactly zero.

    Besides all metals are crystalline, even if the size of the crystalline domains (the grains) change according to the conditions of cooling, seeding, etc. Only alloys have been obtained in an amorphous state for extremely high cooling rates.

    In general it is not the crystalline or amorphous character of a material that imparts transparency, it is the characteristic dimensions of the material compared to the incident wavelength. If there is a periodicity (crystals) on a scale similar to the wavelength, diffraction occurs, if a random distribution (of particles, domains, ...) exists on the same scale, diffusion occurs. That is why semi-crystalline polypropylene is translucent while amorphous PP is transparent to visible light.