Recent content by tjej

This won't answer your question directly but might help. I work for a web (ie newspaper) printer with a rewinder and only the take up roll is driven. The feed roll has a brake to regulate the tension. The tensile strength of the paper is more than enough. When the paper is on the press it...

The efficiency is likely to be closer to the normal 50% given the air gap will be wider to allow for the fact that the vehicle will have to dynamically align itself down the channel. Given the speed, that is lot of energy and so means a lot of heat. If the heat is dissipated in the remaining...

There are other challenges for the Hyperloop design such as the problem of dissipating heat from the LIM (which is only 50%-75% efficient). The waste will turn up as heat and most of this would go the rotor on the vechicle. One the cost side I have seen an estimate for the costs of a pair of...

There has been a system running in Jakarta for 24 years and there are no reports of rats being a problem. (martens aren't native to either Brazil or Indonesia so we won't know about that.) Any comments on the underlying physics?

Thanks. I was aware of the precedent. You mean the 19th century. (It would have been really impressive if it was the 10th.) Rubber seals have replaced leather ones and electric motors have replaced steam engines. I'm really interested to see if the efficiency of atmospheric railways can be...

There is a new automated people mover (APM) opening in Porto Alegre, Brazil called Aeromovel; it is built using atmospheric railway principles (see http://www.copa2014.gov.br/en/noticia/100-national-technology-aeromovel-reaches-its-final-construction-stages-porto-alegre) The vehicles runs...