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Comment Re:We vote on leaders not lightbulbs (Score 1) 1146

"incandescent bulbs are 10% efficient? Try 2% efficient at creating light we can read by"

You need to specify what you divide by what. For radiation in the range 400-700 nm (visible light), a black body at 2800 K is about 6% efficient, watt per watt. Luminous efficiency is corrected for the sensitivity of the eye, such that only monochromatic green light would be able to reach 100%. An ideal white source would be about 40% in this definition and a light bulb 2%.

Comment Re:On the Early player advantage (Score 1) 174

like Iceland and the US Pacific Northwest, that use hydropower. Water flowing through a turbine really isn't causing much environmental damage

Except that the hydropower that is used this way cannot be transported to other regions and displace coal power. Now for an isolated island like Iceland, transporting is not an option, but I guess for the US Pacific Northwest it may be.

Comment Re:Unplug (Score 1) 327

Whether something feels hot or cool isn't a good indicator. That varies greatly depending on venting, and size of the housing. So your tiny little cell phone charger might *feel* just as warm as an old, *large* transformer, while consuming several times as much power.

Well duh, of course I'm not comparing an old-style wall wart in front of a fan to a modern wall wart in a closed box. Anyway, you would have to compare temperature difference (relative to environment) multiplied by surface area. Since most switched-mode wall warts are much smaller than iron-core transformers with the same power, the evidence that switched-mode wall warts waste very little electricity only becomes stronger: small area cool to the touch versus large hot area.

Comment Re:Unplug (Score 3, Informative) 327

Modern switched-mode wall warts use negligible power in stand-by. You can feel it: they stay cool when not in use, unlike the old ones with iron-core transformers.

Bigger hidden consumers over here are the pump of the hot water system (100 W while running) and the airconditioner in standby. I use the ac only a few days per year, but I found out that it sips 15 kWh per month waiting for a signal from the remote control.

Comment Re:Why a first calculator anyway? (Score 1) 328

I can quickly test an idea in the time it takes someone to open their laptop and wait for it to come out of suspend.

I take it that I'm not that much into electronics, but when I'm at work and not in a meeting, I usually have a computer nearby, usually with Gnuplot running in some window, which I use both as a symbolic calculator and as a quick way to plot mathematically expression. (Gnuplot can also handle complex-number arithmetic, which may be relevant for analog electronics). Could you give an example of something that would be easier to do in a calculator?

Comment Re:what cost (Score 2) 363

My huge power draw is the heater and the hot water heater. No problem. We have these things called Batteries...

Huh? From sunlight to electricity to battery storage to hot water sounds like a rather inefficient and expensive roundtrip. Why don't you use a solar water heater and/or store hot water in a well insulated tank?

Comment Why a first calculator anyway? (Score 1) 328

It's not really an answer to the Ask Slashdot question, but I don't see why one would want to use a non-approved programmed calculator.

The point of a calculator during exams is that you have a single tool with well defined capabilities, so as not to get an unfair advantage above students using a different brand of tool. For actual (professional) engineering calculations you will use a computer with decent programming tools (matlab, python, C/C++, or whatever your favorite is). In my 22 years of university (physics), scientific research, and industrial engineering, I have never felt the need for a fancy calculator. Nowadays I have RealCalc (Android app, clone of the decades-old Casio FX-8x line of non-programmable calculators) if I need a quick calculation during a meeting and a computer (combined with pen and paper) for everything else.

If your exams require that you have a graphing calculator, you'll probably need one. But I've never seen them used around me (R&D department counting a few thousand mechanical engineers).

Comment Re:Stupid idiot messages (Score 4, Insightful) 526

"'Car needs service. Car may not restart.' WTF? "

I'd say this is exactly the amount of detail that you need while driving. Really, what would be the added practical value of "Battery bank 7 temperature exceeded threshold level 1 based on mean power over last 15 minutes, click here to see a plot" for your decision to stop now, drive home, or drive directly to the service station?

I wouldn't be surprised if more details can be found somewhere under "advanced status" or something.

Comment Re:Re public transport for free? (Score 1) 96

People are not going to suddenly spend half their day on a bus driving back and forth because suddenly it's free

Actually, I think that that is exactly what will happen. See the other comment about loitering (sitting on the bus/train forever to keep warm). Other example: some 20 years ago, Netherlands introduced unlimited "free" public transport (bus and nation-wide trains) for students (age 18-24 years). It created a huge surge in passenger numbers, much more than what could be covered by the reduction in monthly allowances. So much that in the next few years, they restricted the hours of usage *and* increased the fees. I also recall that several courier services popped up, operated by students using their unlimited subscription to deliver packages on the other side of the country.

Comment Re public transport for free? (Score 1) 96

how about make public transport free and just pay for it through a flat levy?

I'm all for subsidizing this kind of public infrastructure if only because the alternative is using tax money to deal with all the extra traffic. However, I don't believe that making it free is a good idea. Transportation, public or not, still costs money; with free public transport, all financial incentives for people to reduce unnecessary movements disappear, as do financial incentives for the operators to increase efficiency. This is asking for ever increasing costs of the public transport system.

Comment Re:Geo-fencing, nothing more. (Score 2) 188

"If stuff is bought with a stolen credit card then the credit card company or the bank bears the risk."

I highly doubt that; the thief could have a friend set up an online merchant, make $2000 purchases of virtual goods and split the profit.

The reason merchants are so careful is that the merchants will have to eat the loss in case of a fraudulent transaction.

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