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Comment: Re:Wow. (Score 1) 187

by Rei (#47444479) Attached to: Rocket Scientist Designs "Flare" Pot That Cooks Food 40% Faster

That I actually have done ;) On a 60-degree slope down into a deep canyon nonetheless! Also there's manmade objects and yes, *gasp* trees in some places ;) The country isn't totally treeless!

But yes, it's not exactly a very practical solution for Iceland. I'd really prefer something more designed for both roles, hanging and on the ground.

Comment: Re:Wow. (Score 1) 187

by Rei (#47443739) Attached to: Rocket Scientist Designs "Flare" Pot That Cooks Food 40% Faster

Are you talking about a Hennessy? I love mine. And I live in Iceland, where it's harder to use. I have no clue where you're getting that they're heavy. Unless you're comparing the regular nylon version to a silnylon tent, rather than nylon to nylon, silnylon to silnylon. The one-man silnylon versions are in the ballpark of 800 grams, including the fly. You kind of have to adapt them to use them as tents on the ground, though, they're not designed for that (but it is possible). Another criticism of them I have is that underside insulation seems to be an afterthought, and I'm not a big fan of their insulation kit (there's no reason it should be foam, I'd like a self-inflating mat). Their snakeskin packing system works well, but you can't pack up the hammock with the insulation on it; honestly, I'd love it if I could have my sleeping bag, hammock, and insulation all roll up as one element. And if had been designed to work both a tent and a hammock from the beginning, the insulation could double as a sleeping pad.

Comment: Re:Wow. (Score 5, Insightful) 187

by Rei (#47442911) Attached to: Rocket Scientist Designs "Flare" Pot That Cooks Food 40% Faster

Not to mention that as a mountaineer, I'd think he'd care more about cooking efficiency than cook time. And while it's great to utilize the flame energy more efficiently, there's a far more significant optimization one can do - make insulated cozies that fit your pots. Bring to a boil, shut off the heat, put the pot it in the cozy and let it cook. For my pots, I made an underpiece and a lid that fits over each other, both out of aluminized foam; it works very well.

(Of course, he could be one of those people that doesn't eat any "cooked" meals, only the "just add boiling water" meals. In that case, then I guess it's all about the efficiency of using the energy from the flame

What I want to see in backpacking is a full integrated system. Where the tent is a hammock is a backpack is a ground cloth is a pack cover is a camp chair and so on down the line, where most components serve multiple uses. When I think about how much "fabric" and "rigid structures" I carry with me that if designed properly could be eliminated, it just seems like a waste.

Comment: Re:Ted Postol very bias opinion. (Score 4, Insightful) 325

by Rei (#47440615) Attached to: A Skeptical View of Israel's Iron Dome Rocket Defense System

Actually, the key thing for them is "cheap". They need to keep costing sub-$1k missiles in the ballpark of these Iron dome systems - the more, the better. They might as well just omit the warheads to save money and increase range. Every $50k shot Israel fires with those systems costs 25 Israelis' annual tax contribution to the IDF. Every $55m system they deploy costs 27.500 Israelis' IDF tax contributions.

Palestinians are poor, but they're not *that* poor that they can't leverage those kind of lopsided financial ratios.

Comment: Re:Subject bait (Score 4, Insightful) 325

by Rei (#47440537) Attached to: A Skeptical View of Israel's Iron Dome Rocket Defense System

No, in the case of Iron Dome, that's only PR too. They're shooting $50k+ missiles at $800 rockets. Even after factoring in that Israel's per-capita GDP is 20 times that of Palestine's, that's still a losing proposition, even *if* they had a 100% hit rate (which this article is suggesting it's anything-but) and assuming that you get the launcher, radar, etc for free instead of the actual $55 million per unit. It's in Palestine's best interests that Israel deploy as many of them as possible and try to shoot down every last rocket, because every shekel they spend on Iron Domes and missiles is a shekel they don't spend on jets, tanks, and bombs.

Comment: That said... (Score 4, Informative) 59

by Rei (#47437451) Attached to: Sand-Based Anode Triples Lithium-Ion Battery Performance

... the greater your capacity, the less cycle life matters. If you want an EV that battery that will run a 250Wh/mi vehicle for an average 20 miles a day for 15 years, then you want it to cycle through about 30MWh. If you use a 100 mile (25kWh) battery pack, then that's 1100 cycles. If you use a 200 mile (50kWh) battery pack, then that's 550 cycles. If you use a 400 mile (100kWh) battery pack, then that's a mere 275 cycles. Actually, the improvement is even better than that in the real world, because the greater your capacity vs. how far you're actually driving, the more you can cycle the cells through a less destructive state of charge range rather than doing deep discharges.

A lot of people picture battery packs in EVs backwards, they think that things like hybrids stress the packs the least, PHEVs moderately, and EVs the worst. But it's reversed. If you look at how big hybrid packs are vs. how much electric range they hold, you'll see that they're disproportionately large, even after you factor in any differences in Wh/kg. The reason is that because hybrid packs get cycled so much, they have to keep the cycling in a very narrow state of charge range, only allowing shallow discharges. So if you only have a narrow discharge range, you have to make your pack bigger to make up for it. EVs can discharge through much more of their pack because they need fewer total cycles and only rarely go down toward the lower end of their allowable discharge range. Some EVs also let you limit the max that your pack charges up to to further extend lifespan (it's usually destructive both to use the very top end and the bottom end of the discharge range).

Comment: Re:Manager (Score 1, Interesting) 199

by mfh (#47437421) Attached to: New Microsoft CEO Vows To Shake Up Corporate Culture

Weasels that know corporate double speak are ruining everything though. You know we don't mourn the T-rex. We talk about the dinosaurs as being really big and dumb.

They were all psychopaths!! Lizard brains.

When the cockroaches are mulling over what our existences might have been like, they will all say that the weasels died out because of our stupidity and overconfidence. They'll say we were monsters, too. Big and dumb. Lizard brains.

Comment: Re:Correct me if I'm wrong, but... (Score 4, Informative) 59

by Rei (#47437401) Attached to: Sand-Based Anode Triples Lithium-Ion Battery Performance

1024 mAhg1 is excellent capacity even vs. brand new graphite or amorphous carbon, about 3x as much as graphite's maximum. Silicon's theoretical max is 8-10x that of graphite, but the main problem with it is durability, it tends to tear itself apart on loading. There are silicon anodes in some newer li-ion cells on the market, but the tech is in its infancy.

That said, the real papers you want to be on the lookout for are cathode improvements, there's a lot more potential for volume/mass reduction there than in the anode. But it seems to be a more difficult challenge. Getting a 3x improvement in anode density is absolutely not the same a getting a 3x improvement in battery life.

Comment: Re:Little Bit of History Repeating. (Score 5, Insightful) 59

by Rei (#47437377) Attached to: Sand-Based Anode Triples Lithium-Ion Battery Performance

Commercial li-ion battery energy densities have continued to improve during that time period, including the commercial introduction of cells with silicon anodes. Of course, silicon anodes are a new tech, so there's a great deal of room for improvement, which probably won't come close to "maxing out" for a decade or more.

Of course, that said, this article is your typical fluff piece following the guidelines of fluff science reporting.

1. Present an oversimplified version of one technology challenge that may or may not address the biggest issue and certainly doesn't address all of them - but don't mention that.
2. Introduce an outside-the-establishment loner with a passion - or at least someone you can try to present as "outside the establishment" and glaze over anyone who helped him.
3. Loner gets a "vision" based on some everyday activity
4. Present their solution and make it out to be a huge revolution that will certainly solve all our problems - if they can only get corporate backing / funding!

I think these sort of articles hurt the image of science because people read them, think "OMG, all our problems are solved!", then when everything's not solved afterward, fail to trust science in the future. For example, in this case, the most important element to improve is the cathode, not the anode. And cathode improvements are less common and usually less major than anode improvements. There's also tons of different anode improvements out there in various stages of research. Pretty much all of the silicon ones get way better than graphite or amorphous carbon.

That doesn't mean that this isnt an important paper - actually, from looking at it, it looks pretty good. It's just not "all that".

BTW, anyone know how credible this journal is? I see it's hosted on Nature.com but not part of Nature, and I tried to find an impact rating for it but couldn't.

Polymer physicists are into chains.

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