Forgot your password?
typodupeerror

Comment: Re:Renew this! (Score 1) 437

by Garfong (#47912655) Attached to: If Tesla Can Run Its Gigafactory On 100% Renewables, Why Can't Others?

You're probably right -- I do need to review my thermo. University was many years ago, and thermo was taught in a hot class room in the middle of summer by a prof who was in his 60s and coasting to retirement. But I meant to claim that lithium battery chemistry was thermodynamically reversible _in theory_, whereas a heat engine (such as a gasoline engine) is not. Although I'm not really sure if this is true either, but practical efficiencies are in the 90% range (according to the sources cited by wikipedia), which includes internal impedances, and other real-world losses. So it seems likely to either be theoretically thermodynamically reversible, or very close.

But you were the one who said the hydrocarbons were being burned (in your previous post). In this case, lithium battery discharge/recharge cycle is up to ~90% efficient, whereas gasoline burning has an average efficiency of 25-35%. So ignoring the efficiency of the hypothetical gasoline recovery process, that's a difference of at least 55%.

I think it's ironic that you consider a difference between 100% and 90% completely invalidates what I'm saying, but me pointing out a difference between 90% and 35% is being pedantic.

Comment: Re:Renew this! (Score 1) 437

by Garfong (#47893185) Attached to: If Tesla Can Run Its Gigafactory On 100% Renewables, Why Can't Others?

Recharging lithium batteries and recovering hydrocarbons from exhaust waste are not equivalent. Lithium battery discharge is a reversible process, so the original state can be recovered by input of the same amount of energy as was originally extracted from the system. Gasoline & turbine engines (like all heat engines) are non-reversible, which means it takes more energy to recover the initial state than was extracted as useful work. This is because only a portion of the energy produced by burning hydrocarbons can be extracted as work -- the rest escapes as heat.

Comment: Re:define "customer" (Score 2) 287

by Garfong (#47890763) Attached to: German Court: Google Must Stop Ignoring Customer E-mails

I don't know if this applies here, but from what I hear contract law is very different in Germany. The example I've heard is when you buy something from a store in a common-law country, there's an implied contract for sale of the goods. In Germany, apparently there's about three implied contracts.

Comment: Re:Quite accurately? (Score 1) 170

by Garfong (#47883329) Attached to: Universal Big Bang Lithium Deficit Confirmed

1. With a BA in physics (mid-90's), I was taught about the Big Bang and elements calculation multiple times. In every single instance I was shown the calculated and observed percentages, and they were always given as a good match, as part of the proof. I'm really confused that now it's been known for decades that they *don't* match. Were my books lying to me? Was this observation adjusted the year I graduated college, and I just missed the controversy?

It's possible that for the version of the model you were given, order of magnitude was considered a "good match". I still remember my prof leading our class through a calculation of heat capacity of copper using quantum mechanics, and getting a value which was off by about this much, and it was considered a "good match" because given all the simplifications needed, even getting something in the right neighborhood seen as confirmation of the overall approach.

Also, according to Wikipedia, measurements of the cosmic microwave background radiation within the last 15 years have fixed some of the parameters of Big Bang nucleosynthesis, so it's possible what was considered a minor discrepancy which may be explained by future research has become a discrepancy which has been highlighted by recent research.

2. I'm also really curious to hear which elements have a *higher* concentration, to make up for the missing lithium. If we were just short a bunch of lithium, all of the other elements would be higher, percentage wise, and thus all of them would be off. Since the others are spot-on, I've got to think there's at least one element out there that's disproportionately high to balance it out.

Not necessarily. From what I remember, Hydrogen and Helium are so much more abundant in the universe than Lithium, that a 3x difference in Lithium concentration could easily be 1% or less in H or He concentrations.

Comment: Re:Straight to the pointless debate (Score 4, Interesting) 136

by Garfong (#47819945) Attached to: Out of the Warehouse: Climate Researchers Rescue Long-Lost Satellite Images

Or another way of thinking of it is you're using the measured data to estimate a hidden variable which is what you're really interested in. E.g. in this case you have a number of measurements near cities, and you're trying to estimate the global/wide-area average temperature. So you apply a correction to get from city temperature to an estimate of the wide-area average temperature.

(This is mostly in response to GP).

Comment: Re:How is CO2 leading cause of warming? (Score 1) 143

by Garfong (#47664685) Attached to: NASA's Greenhouse Gas Observatory Captures 'First Light'

The ability to accurately model the details of a system is usually not required to model the average, long term, behaviour of the system.

Rolling dice is a complex chaotic system. Yet despite my complete inability to predict the results of any roll, I'm confident that casinos will make money on craps tables.

Comment: Re:NIMBY at its finest (Score 2) 409

If I thought that generating papers had no bearing on choice of research, I would have said that. Since that's not what I said, please don't assume that's secretly what I meant.

But (ideally) high quality papers will come from high quality research. I think you're doing a huge disservice to the doctor who has a 60-90% chance of dying, and the researchers working with him. If all they cared about was their tenure review and grant cycles, they could probably find some research that had 100% less chance of dying of a strange African disease.

It is surely a great calamity for a human being to have no obsessions. - Robert Bly

Working...