Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
×

Comment Re:1,382 degrees F (Score 1) 132

I did wonder about the exact temperature required and naturally assumed it was a carefully controlled centigrade temperature. Of course, it's just another case of mis-conversion from one unit to another. 1382 F is the exact conversion from 750 C, a value only given to 2 sf. 1400 F would be a more appropriate conversion if you have to convert it at all.

Comment Waste of energy in manufacture (Score 5, Insightful) 197

Some quick back of the envelope calculations: FTFA, each tile generates "2.1 W" per step. If we assume a typical step time of 500ms based a pace of 120 steps per minute this could be interpreted as about 1.05J captured per step.

The casing is made from stainless steel which required about 53 MJ/kg for production in 2004. If we assume a tile casing mass of 2kg that is 106 MJ required for the steel production alone.

The shopping centre may be open around 10 hours a day with perhaps 20 seconds between each step averaged over a typical day. This is 1800 steps per day at 1.05J per step giving a total of 1890 J captured per day. Assuming 100% efficiency and a never-closing shopping centre, this gives an energy breakeven for the steel alone of around 56000 days or 153 years.

I know that other factors are in play such as the potential to raise awareness of environmental issues but this is ridiculous. I noticed that the award that the guy is in the running for is sponsored by Shell and part of me suspects that they know that these things are crap but want to be seen to promote something like this which appeals to the public and appears "green".

Comment Re:Photos not allowed during police actions, citiz (Score 1) 268

This is something I really need to look at in more detail. If you try astrophotography with a lot of digital cameras, you'll find that the H-alpha wavelength (around 650nm, red) is greatly diminished by the filter. However, an IR LED (peak wavelength about 960nm) shows up brightly in digital photos taken on the same camera. It seems more sensible to include a short-pass filter as they are cheaper to manufacture but perhaps they are band-pass? Just a thought; may be totally off here.

Comment Re:Brisband = Brisbane (Score 1) 214

I think your best one was to say that the average rainfall is around 6.1 cubic inches! The error is confusing millilitres with millimetres. The first is a measurement of volume (about 6.1 cubic inches) and the second is a length, interpreted in this case as a depth. The area of Brisbane according to wikipedia (I know it's been raining in more than one place but this is an approximation) is 5904.8 square kilometers which gives a total typical rainfall for this area for this month of about 590 million tons or about 3.6x10^13 cubic inches.

I'm sure there should be some sort of record broken for most orders of magnitude out here :-)

Comment Re:No, no premises required (Score 1) 309

As a little off-topic trivia, slavery (as in the ownership of one human by another) only became illegal in the UK on 6th April 2010 (source).

Slavery was abolished in stages throughout the British Empire in the 19th Century but the status of slave was never acknowledged in the UK so it was never illegal to own one since they didn't exist!

Comment Re:It really depends on the quality of the course (Score 1) 118

This is almost exactly what Jonathan Shorr of the University of Baltimore was quoted as saying by BBC news. The students think they are having an easy course but in fact are "tricked" into learning something. I don't have a problem with this per se but surely not for adults. This is the kind of technique you use with young children who don't want to learn. If people at university don't want to learn (or can't learn without being hoodwinked) then they shouldn't be there.

Comment Re:Like there's never been a GAS STATION fire (Score 1) 357

Indeed. With any flammable fuel there is always the potential for problems to arise leading to fire or other danger. We think we've got petroleum products fairly well sussed but every now and then something goes wrong. The key is to learn from mistakes and make future use of any given fuel or technology better and more idiot-proof.

Slashdot Top Deals

UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things. -- Doug Gwyn

Working...