Posts by Alan Braggins

Pentax K-m entry-level digital SLR

Why a DSLR?

> you were thinking of a top-end compact ... What exactly do you get in a DSLR that you don't get in an FZ28?

According to dpreview, the K-m has a sensor size of 23.5 x 15.7 mm and the FZ28 6.13 x 4.60 mm.

If that doesn't result in reduced noise and better low light performance for the K-m, then Pentax are doing something badly wrong.

But I suspect it's more that you might not have been planning to change lenses, but a sufficiently good value DSLR might make you change your mind and decide you want the option in the future after all.

UK sportscar makers announce electric models

Hydrogen

Hydrogen is only useful as a storage mechanism, it isn't a primary fuel - there are no hydrogen mines where we can get significant amounts of hydrogen gas, we have to use energy from some other source to get it out of hydrocarbons or water. So, like electricity, it just moves the problem somewhere else (which does allow it to be moved somewhere more efficient with better pollution control measures).

On the other hand if you do have some other source of plentiful green energy, you can use it to synthesize oil - see <a href=http://en.wikipedia.org/wiki/Fischer-Tropsch_process>http://en.wikipedia.org/wiki/Fischer-Tropsch_process</a>. It won't give you the nonexistent or clean exhaust that electric vehicles or burning hydrogen will, but it can be carbon neutral if you use renewable or non-fossil energy and atmospheric carbon dixide as inputs to the synthesis, and we can go on using existing long range vehicles and the existing distribution infrastructure. It's more expensive than just pumping the stuff out of the ground, of course, but it won't get more and more expensive as it gets scarcer.

(Technically, there is enough uranium to provide our energy needs at our current usage for centuries if we use it in breeder reactors, but the political problems are huge.)

British boffins perfect process to make any item '100% waterproof'

Goretex

Goretex membrane isn't one way, nor a sponge, it has tiny holes that are small enough to let water vapour though but not let droplets of liquid water through. At least until they get clogged up.

http://en.wikipedia.org/wiki/Gore-Tex#Design

http://www.gore-tex.co.uk

Whether fabric treated like this would behave the same way would depend on the fibre size and how tightly woven it was, or how porous a non-woven material was.