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Comment: Re:Well heck (Score 2) 99

by RenderSeven (#46660637) Attached to: What's In a Username? the Power of Gamer Tags
'BotNet' always gets a response, especially if you play like a bot for a minute or two. You either get treated like a badly written 'bot and everyone swarms in for an easy kill, or treat you like an omniscient 'bot and get avoided. Either way, it can be used to your advantage. If nothing else you get some extra shots off while the other team is busily reporting you to the moderators.

Comment: Re:so what about all my old devices? (Score 3, Informative) 254

by RenderSeven (#46096697) Attached to: Old-school Wi-Fi Is Slowing Down Networks, Cisco Says
I returned my last Netgear and LinkSys units. It was the cheap Monoprice one that worked right out of the box. I have no bad experiences with *any* of their stuff. In general I find that the name brands are so furiously writing crap front ends and bloated install utilities so that complete morons can use them, they forgot to make the even slightly advanced features (i.e. gateway only mode) work properly. I prefer unbranded goods that dont need a DVD full of garbage to install them ("Uncheck this box if you *dont* want to link your router to your Facebook account, submit traffic reports to Netgear, and receive our twice daily newsletter").

Comment: Re: So what happens to the hydrogen? That's usable (Score 1) 375

No. The pressure on your body is equal, since youre mostly made of uncompressable water so you dont get crushed by 100 psi at rec depths. All pressures stay pretty balanced except for the 1000PSI in your tank. Thats why more gasses are required for breathing at deeper levels. 2x at 2 atmospheres, 3x at 3 atmospheres. You still inhale maybe a liter but its a compressed liter that would be 3 liters on the surface. Thats why you NEVER hold your breath during an ascent, you 'splode. And it works the other way too, you have to keep filling your buoyancy vest as you descend to compensate for the compression from depth reducing buoyancy, and releasing as you ascend. There is no "less" pressure area or differential for the filter to make use of.

I suppose you could say breathing supplies a differential, but its surprisingly low PSI and no where near the energy required to push the necessary volume of water through. You could contrive some energy harvesting thingy with thanks and turbines that you constantly hyperventilate into, but youre right back to a massive rebreather, except you have to breathe like crazy to power it enough to get basically the output water volume fo a jet boat..

Comment: Re: So what happens to the hydrogen? That's usable (Score 2) 375

The dives Ive seen rebreathers used on were the Great Blue Hole and Terneffe Reef in Belize. If you dive, they should both be on your bucket list! And, they are both dives that taunt you with the bottom rows of the recreational dive limits. I spent 7 minutes at 145 feet, where my dive computer gave up beeping warnings at me and just sulked for the remainder of the dive. It was a great opportunity to experience nitrogen narcosis in a fairly well supervised trip. This page here shows the dive profiles; escorted trips dive the south grotto which pushes the 110' limit just getting there. Rebreathers give you a lot more flexibility to explore, with better bottom times.

A problem using Triton here is all the water is anaerobic, there is no oxygen and thus no sea life below the thermocline, and nothing for the Triton or LikeAFish to extract. Conditions like that can happen unexpectedly anywhere on medium depth dives. Thermoclines shift and below them there is little interaction with oxygenated surface water. So Triton et al would presumably just shut down suddenly and without warning or any reserve even during shallow dives. Not good. Carrying a pony bottle would be mandatory.

Thanks for the link on other dissolved gasses. Nitrogen is available then at ~150% by volume of oxygen. Lets make some assumptions: Troton could use the same membrane for both oxygen and nitrogen; that they both extract 50% efficiency. You need 12L to get a breath of O2 but 40L to get the nitrogen. At 15 bpm we're up to 600 lpm to process. at surface pressure. At 60 foot depth thats 3 atmospheres, so 1800 liters per minute! A sump pump at 1/4 HP does about 80 lpm at no head/pressure, so 5 HP if the triton needs no pressure for the membrane, which I guess is does (reverse osmosis needs about 50psi) so we are probably close to 20HP to run it. Thats a gas-burning outboard motor, not a pair of Duracell AA's and a few CC's of motor.

You and I between us have almost assuredly done more real work on the Triton than the clown that "invented" it; a college sophomore with no engineering background except a working knowledge of Solidworks and access to a 3D printer, and a single escorted rec dive to his credit.

Comment: Re: So what happens to the hydrogen? That's usable (Score 1) 375

Like-a-fish seems interesting enough, but both that and the unobtanium ignore the basic fact that there is a *hell* of a lot more to breathing underwater than finding the oxygen. You need a large quantity of inert gasses at the correct mixture and relative pressure to carry the oxygen and maintain 'normal' respiration. You either carry it in a tank, or reuse it with a rebreather along with a CO2 scrubber. Anyone thats used a rebreather will testify they are heavy, complex, and relatively dangerous compared to a simple tank. An oxygen supply for the rebreather is the easy part. Any number of superoxide compounds work great. Heck an oxygen candle works fine under water. But whats to be gained by not using a simple oxygen tank?

The like-a-fish thingy tacitly implies this by claiming it has applications in underwater habitats. Yep I can see that. But scuba? No, never, not even close.

(I dove with someone using a rebreather once. When he regained consciousness, I swore I'd never ever trust my life to one.)

((If the Triton thing ever could be built to push 200 lpm with a battery and compressor that small, it would revolutionize underwater propulsion. The savings in swimming energy alone would reduce respiration so dramatically during a dive there wouldnt be much need for the oxygen extraction in the first place!))

Comment: Re: So what happens to the hydrogen? That's usable (Score 4, Informative) 375

90 liters of water per minute, at 100% efficiency, at the surface where oxygen is most abundant. So, at 50% efficiency, at 30 feet, yes probably 400 lpm. Minimum 1/4 HP pump and probably more like 4 HP just to handle O2 extraction. From a battery about the size of your cell phone battery? But thats just one of a hundred things wrong with the idea. Its complete BS.

Chemist who falls in acid is absorbed in work.