Battery materials are reported in mAh/g because this way they are independent of the battery size. You could stuff say 50g of this material into a battery meant for a car or 1/2g of this material into a battery meant for testing in a lab and you can roughly estimate the energy storage abitlity of the material. Both of these cells will have a voltage of about 3.7V on average. The units of mAh/g tells you about the amount of lithium that can be stored by this particular material so that it can be compared against other materials on an equal basis.

Huh? You don't consider numerical methods that approximate integrals to be true calculus?
This is true calculus. You don't need to know anything about the future voltage curve or current, just the past.

This is the equation to calculate capacity consumed in a battery (which is a numerical approximation to an integral):

capacity consumed = capacity at last check + (current + current at last check)/2*(present time - time at last check)

The equation above is the trapezoidal rule (http://en.wikipedia.org/wiki/Trapezoidal_rule) applied to the integral in my first post.

I hate to pull this one out, but trust me, I'm a battery scientist that makes mathematical models of batteries for a living.

To calculate the capacity used in a battery, you apply the following equation:

capacity = integral(current, dt)

So yes, this is calculus. To solve this you would use a numerical approximation to the integral, such as the trapezoidal rule.

I love lastpass. No need to remember login info at all (except for your master password). The _only_ problem is when using my phone/ipad, it's a bit difficult to dig up passwords.

PS:

Yes it does. It allows you to do something useful with your numerical codes. Maybe not needed for academia, but certainly for other industries.

I jumped from Matlab to Scipy/Numpy, skipped Octave, but I'm so happy with Scipy/Numpy that I wouldn't consider using Octave.

From a purely numerics point of view, I'm sure Octave has all the features that Scipy/Numpy has. Most of the benefits of Scipy/Numpy come from the Python programming language itself, which I have to assume is much more developed than Octave's language. Being able to write GUIs for your scientific apps using tkinter (or some other library) or reading/writing to excel formats directly or wrapping your code up using pyexe for distribution or interfacing your python code with the web or a database is just the start of the Python advantages (after a quick search I see that Octave can do some of these things, but I'm sure Octave doesn't have all the libraries that Python has).

IMHO, if scipy/numpy ever get working with PyPy, then this would truly be amazing.

TFA didn't suggest that she was forced.It said she took the advice of the TSA worker over the advice of her doctor. The doctor's note said to avoid the body scanner, she asked the TSA worker if it was ok, and the TSA worker said yes. IMHO, a doctor has more credibility over a TSA worker in this case, I'm not sure why she didn't think so.

I agree. I don't know anybody who uses a computer and doesn't rely on Microsoft Office. And crossover office is not good enough (it might work well enough, but it's not easy enough for my parents to install themselves).

It comes down to the fact that distros like Ubuntu are still too difficult to use for normal folks. Give your parents Ubuntu and see how far they get trying to play a DVD or uploading music to an ipod.

Actually this is exactly what I want. I need something like an Asus RTN16, but cheaper. The Raspberry Pi seems to fit this bill quite nicely.

"NHTSA in fact drains the gas tanks on gas cars (including the Volt!) BEFORE they wreck them because of the danger of the gasoline."

Do you have a reference for this? Not that I don't believe you, but if this is true, GM just got a whole load of bad press which may have set back the electric car over something that was NHTSA's fault. It's unbelievable that they wouldn't test gasoline cars and electric cars on the same footing. If they first drain the gas tank then they HAVE to drain the battery before the test for a good comparison.

I think the tweet idea is slightly different. For example, a lot of work that a scientist does is collecting data to make sure equipment is working properly. Usually these experiments aren't worth publishing and probably wouldn't make it past a peer review because 1) they're usually not novel experiments 2) they don't tell a story or add much value, but I think it could be useful to share this type of data. I mean, if you've collected it, why not share it?

My smartphone changed my life (I think for the better). It's the GPS, not the web browsing that is the best feature. Last week I went on a business trip, rented a car, didn't have to bother with maps or worry about getting lost, my phone told me where to go.

This is getting blown way out of proportion.

See this article for another view: http://www.economist.com/node/21541395

Specifically the last paragraph:
"What is left unsaid in all this is the fact that conventional cars with a tank full of petrol are far greater fire hazards than electric cars will ever be. Some 185,000 vehicles catch fire in America each year, with no fewer than 285 people dying as a consequence. But, then, people have been living with the hazard of petrol for over a century. Irrationally, electric-vehicle fires are perceived as somehow more worrisome simply because they are new."

In this case, the backplate of the iphone had been replaced (you can tell from the apple logo in the picture). Obviously I don't know if this was the cause though, but perhaps the backplate was replaced because the original broke during a fall which may have jolted some internal circuitry close to the battery causing a local hotspot near the battery and then thermal runaway. Somehow I doubt that the battery would have been punctured just by dropping/replacing the backplate though.

Apple purchasing this patent from Xerox is essentially equivalent to Apple outsourcing their R&D. Same end result.