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Comment: Re: Well duh! (Score 3, Informative) 166

by nojayuk (#43791263) Attached to: EPA Makes a Rad Decision

Cesium doesn't linger in mammals. Depending on the tissues it lodges in after inhalation or ingestion (bone, fat, muscle etc.) its biological halflife is between 70 and 120 days i.e. half the cesium taken in will be pissed away or excreted in that time, then half the residue over the next period and so on. It's the same with strontium and a number of other problem specimens in the radiochemical zoo although the half-life varies from element to element.

Iodine-131 is the major contamination problem from fission releases, it's preferentially concentrated in the thyroid and is very radioactive but because of that it goes away quite quickly, with a halflife of only 8 days or so and superdosing with iodine tablets will prevent uptake of I-131 to a large extent. Hospitals and therapeutic facilities that use I-131 to "burn out" thyroid cancers flush residues into the sewer systems leading to the occasional panic when I-131 is detected in miniscule amounts in rivers, lakes etc. downstream.

Comment: Re:The alternative, of course (Score 3, Insightful) 166

by nojayuk (#43789297) Attached to: EPA Makes a Rad Decision

Actually Japan didn't ban bananas. The Forbes writer got it wrong.

The new tighter limits on food, water etc. set by Japan were for contamination due to cesium-134 and -137, byproducts of fission usually only found in the wild after a reactor goes wrong or from nuclear explosions. The "natural" levels of radiation from potassium, rubidium etc. are already factored in to the safety regs.

I'm in Japan at the moment, I bought bananas a couple of days ago -- they're a cheap source of energy (and potassium too) since I'm doing a lot of walking around and sightseeing while I'm here.

Comment: Re:Dumb title: CO2 is not "dirty" (Score 3, Informative) 260

by nojayuk (#43607817) Attached to: Energy Production Is As 'Dirty' As Ever

The SEGS, a solar thermal plant in the Mojave Desert uses ground water from a rapidly depleting aquifer to run the condensers for their generating station. The NREL report about trough-based solar thermal energy lists the SEGS's water consumption as 1000 gallons (about 3.5 tonnes in real units) evaporated per MWh generated.

http://www.nrel.gov/csp/troughnet/faqs.html

Oceanside nuclear and other thermal power stations do not evaporate any water, they return seawater warmed by a few degrees from the condensers to the ocean.

Comment: Re:Electric offers many advantages (Score 3, Interesting) 663

by nojayuk (#43599409) Attached to: Ask Slashdot: What If We Don't Run Out of Oil?

The SEGS http://en.wikipedia.org/wiki/Solar_Energy_Generating_Systems in California near Edwards Air Force Base uses pressure washer systems to wash sand and dust off the heat-concentrating mirrors. They use water from the local desert aquifer which is running out. They also use water from that aquifer to cool the condensers on the output side of their steam turbine setup since there's no convenient river or ocean to dump the heat into.

Comment: Re:Cost of nuclear power (Score 1) 218

by nojayuk (#43534815) Attached to: Fukushima Nuclear Plant Cleanup May Take More Than 40 Years

Long-term storage of nuclear waste is paid for by a levy on the electricity generated by the reactors and not by the "taxpayers". In the US that's 0.1c per kWh. The total US fund for that is over 28 billion dollars and rising. In contrast the coal power station operators pay bupkis for long-term treatment of their unconstrained waste output -- any attempt to get them to cough up (so to speak) is a War On Coal.

Comment: Re:Come on CEO... (Score 5, Insightful) 295

by nojayuk (#43514967) Attached to: Microsoft CFO Quits

"Saying that the Ballmer is no worse than Fiorini is no reason to keep Ballmer - there are far better alternatives around."

Such as? Who's available, with the sort of deep knowledge of where MS came from, where it is today and where it is going tomorrow and who can step in and make MS even better than it is today with minimal disruption to the financial bottom line? Hmmm, tricky...

Some day MS is going to have to cope without Steve B., hopefully not in the same way that Apple is handling the loss of Steve Jobs but that day isn't here yet. I find the idea that Ballmer is some kind of liability to MS quite amusing considering what would/will happen to the business if/when he does leave.

Comment: Re:Come on CEO... (Score 4, Insightful) 295

by nojayuk (#43514669) Attached to: Microsoft CFO Quits

Steve Ballmer has been in a senior position at MicroSoft for about thirty years now, unlike the typical bungee boss CEOs and board members of various other high-tech corporations such as HP (remember Carly?). During the time he's been working there MS total turnover has been about half a trillion bucks. I'd say US high-tech businesses could use some more chair-throwers like Ballmer and fewer wily super-geniuses like Fiorina.

Comment: Re:Why?!? (Score 1) 221

by nojayuk (#43477665) Attached to: How NASA Brought the F-1 Rocket Engine Back To Life

Yep, my mistake, a simple brain fart on my part but the RD-180, the RD-171 and its predecessor the RD-170 are all LOX/kerosene like the F-1. They produce 20% more thrust for the amount of fuel and oxidiser they burn and they are available off the shelf. The RD-171 produces more 300,000lb thrust than the last version of the F-1 and it can be tilted and swivelled unlike the old fixed F-1 motor design. I'm not sure if the RD-17x family and derivatives can be throttled; the Saturn V tended to beat up its crew as the first stage emptied at a maximum acceleration of 4G just before separation and a throttleable engine such as the Shuttle had could smooth out the ascent somewhat.

You're right about the mass fraction. The tankerage required for a staging LOX/LH2 rocket would be quite bulky and expensive in terms of launchpad mass. Vehicles like Ariane and the Shuttle ran their main engines nearly all the way to orbit assisted by strapons for the early part of the ascent. I think the Delta 4 with RS-68 engines is the only rocket that takes off and discards a LOX/LH2 stage in flight, trading the very good Isp figure for the mass of the extra tank volume.

Comment: Re:Why?!? (Score 1) 221

by nojayuk (#43454491) Attached to: How NASA Brought the F-1 Rocket Engine Back To Life

The RD-180 engine, a LOX/LH2 engine like the F1, is available off-the-shelf today and has a significantly higher Isp figure (311s sea-level) than the F1 ever had had (263s sea-level). I'd rate that as more than a few fractions more efficient. Its parent engine, the RD-170 and the current RD-171 are both more powerful than the F1 at about 1.8 million lb as compared to the F1's 1.52 million lb. and the RD-171 can similarly be bought off-the-shelf today. Of course they're Russian ex-Soviet designs which gives them cooties in the eyes of some Americans.

Comment: Re:It's easy! (Score 1) 712

by nojayuk (#43389361) Attached to: Set Your Watches For the End of Windows XP

The drag-and-snap windows default behaviour can be switched off. "Control Panel\All Control Panel Items\Ease of Access Center\Make the mouse easier to use" and then enable "Prevent Windows...". Click Apply and windows will no longer snap to screen borders of full-size automatically. Works on both Win7 and Win8.

Comment: Re:Ethanol is a miserable motor fuel (Score 4, Interesting) 238

by nojayuk (#43262661) Attached to: 'Energy Beet' Power Is Coming To America

Quite a few Europeans use vegetable oil in their diesel-engined cars. There's a thriving market for small back-of-the-garage "refineries" processing waste cooking oil from fast-food shops etc. to remove some of the more harmful byproducts like glycerine and water as well as filtering out particulates. You can usually tell if someone's doing this as their car exhaust tends to smell of french fries.

Unused cooking oil (usually sunflower or rapeseed) can be poured into the tank without requiring treatment, especially in older diesel cars and vans with mechanical fuel pumps. In the UK the price of cooking oil is now kept artificially high to match the price of garage forecourt diesel (about UKP 1.40 a litre at the moment) since most of that is tax and too many folks were going to Costco and the like and buying vegetable oil in 5-litre containers for a lot less. Theory says that folks using alternative fuels like biodiesel should pay the same duty as petroleum-derived fuels garner but this doesn't happen much as you might expect.

They have been at a great feast of languages, and stolen the scraps. -- William Shakespeare, "Love's Labour's Lost"

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