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Comment: Re:Engineering win (Score 1) 262

by dak664 (#47271597) Attached to: Elon Musk's Solar City Is Ramping Up Solar Panel Production

But no net energy that way, just pointless multiplication of PV panels. If you want a energy return equal to the energy that went into making the first panel, the first 5 years is a loss - all it does is produce a panel. If you produce no more panels after that it takes another 5 years to recover the energy you could have used 10 years earlier to do something useful. Only after that is net energy. Some of the net energy can be used as a new source of useful energy, the rest to produce more panels and ultimately as the energy source to develop a Dyson sphere. When you stop building panels, it's all net energy.

Comment: Re:Engineering win (Score 1) 262

by dak664 (#47261817) Attached to: Elon Musk's Solar City Is Ramping Up Solar Panel Production

Energy Return on Energy Invested (EROEI) of PV can be 3-4 in favorable cases but the rate of return is also important if you want to multiply the resource. If energy parity for the first panel takes 5 years then its output could produce a second panel in another 5 years. So for 10 years you get no net energy, after which you can tap some of the output for other uses while still continuing to add panels at an accelerating rate. Doesn't matter if you start with 10 or 10 billion, there is still no net energy for 10 years. Starting with a large number could cause energy shortages and social unrest which could end the sustainable growth entirely.

Yes, we should have started 20 years ago.

Comment: Does anyone look at ads anyway? (Score 1) 355

by dak664 (#47059875) Attached to: Google Foresees Ads On Your Refrigerator, Thermostat, and Glasses

I have script and ad blocks and bogus host file entries to speed up browsing but can honestly say I don't pay attention to ads when they get through, When looking for something to buy I do the search and find it hard to believe unsolicited ads bring in any customers.

Are there really people who click through and buy something because an ad says they need it?

Comment: Re:The image formation process is still the same (Score 1) 60

by dak664 (#46685383) Attached to: How To Build a Quantum Telescope

That's the infinite plane wave approximation for lattices of infinite extent. Scattered spherical waves from finite objects will result in some energy passing through the aperture for every spatial frequency. Although it could be difficult to sort out which frequencies are contributing (aliasing). Analysis of the through focal series can do that, also changing the convergence of incident illumination.

But if the source is known to be two points, accurate measurement of the spacing between the resulting PSFs is limited only by signal to noise.

Comment: Re:The image formation process is still the same (Score 3, Insightful) 60

by dak664 (#46683631) Attached to: How To Build a Quantum Telescope

Yes, and what's more diffraction causes no fundamental limit to resolution, it just happens to be the distance between the first zeroes of an interference function. For two point sources of equal intensity that leads to an easily seen contrast difference of around 25% but trained observers can detect 5%. On electronic displays the contrast can be cranked up arbitrarily.

The fundamental limit to resolution is signal-to-nose.

Comment: Re:Can someone explain this theft? (Score 1) 232

by dak664 (#46347469) Attached to: Mt. Gox Shuts Down: Collapse Should Come As No Surprise

Isn't the history of a bitcoin included in the block chain? And the stolen bitcoins identifiable?

If so whoever tries to use one risks being traced, moreover the recipient could be considered as knowingly accepting stolen goods..

Sort of like the haul from a bank robbery having an indelible "This money stolen from Bank X" printed on every bill.

+ - WhatsApp Founder used Nonchangable Airline Ticket to Pressure Facebook-> 1

Submitted by McGruber
McGruber (1417641) writes "In a post on the Flyertalk website (http://www.flyertalk.com/forum/22387891-post72.html), WhatsApp Founder Jan Koum provides another interesting detail about how he steered Whatsapp into a $16 Billion Deal with Facebook (http://mobile.slashdot.org/story/14/02/20/1344218/how-jan-koum-steered-whatsapp-into-16b-facebook-deal):

we announced the deal with Facebook on wednesday after the market closed. during the process, we realized there was a chance we might not be able to get the deal wrapped up and signed on wednesday and it could delay. when the risk of the delay became real, i said: "if we don't get it done on wednesday, it probably wont get done. i have tickets on thursday to fly out to Barcelona which i bought with miles and they are not easily refundable or even possible to change. this has to be done by wednesday or else!!!" ...and so one of the biggest deals in tech history had to be scheduled around my M&M award ticket

"

Link to Original Source

Comment: Re:idle time (Score 1) 533

by dak664 (#46004945) Attached to: Ask Slashdot: What's the Most Often-Run Piece of Code -- Ever?

The idle loop is alive and well in embedded systems. In some cases energy use is minimized by using a slow clock chosen for some small fraction of idle time, in others by sleeping between bursts of fast processing.

x86 idle power reduction under unix started sometime in the late 1990s
https://blogs.oracle.com/bholler/entry/the_most_executed_code_in

Other OS starting using it around 2000
http://en.wikipedia.org/wiki/System_Idle_Process

Thus seti@home launched in 1999 could legitimately claim it made use of otherwise wasted CPU cycles on the Mac and Windows 95 clients.

A committee is a group that keeps the minutes and loses hours. -- Milton Berle

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