Elon Musk to publish hyperloop design by August • Hacker News Board

Re: Elon Musk to publish hyperloop design by August

#171

Post by schiffern » Tue, Jul 16, 2013, 7:47 AM UTC

Turing_Machine wrote: post #168

schiffern wrote: post #119

Earlier quoted context omitted.

I'm in, given that it's the only way to beat the insane right-of-way costs for a transport system in California with a ~20 km turning radius.

I don't know about California in specific, but in the United States as a whole there is plenty of existing and unused/lightly used railroad right of way. Cut a deal with the railroads (most of whom are very, very hungry for cash/investment) and you've got transcontinental capability without needing any eminent domain proceedings or similar obstacles.

The problem is that many railroad right-of-ways just aren't straight enough. The plains states will be fine, but the high-density areas are a pain.

Re: Elon Musk to publish hyperloop design by August

#172

Post by ddeck » Tue, Jul 16, 2013, 8:18 AM UTC

PavlovsCat wrote: post #144

michaelbuckbee wrote: post #123

Earlier quoted context omitted.

To save someone else digging through 4 layers of Twitter/Twitpic attribution and "full size" buttons: http://twitpic.com/cw4pqb/full

That looks like a more elaborate version of something I thought of as a kid, which was basically a vacuum tube going all around the world (one big torus if you will) with carts on super conductive magnets. I was thinking mainly of connecting Tokyo and New York and some place or other in Europe. Cart drives into the station, station gets sealed off and air pumped into it, then passengers leave and board, the doors get…

From the image, there doesn't appear to be any vacuum. The tunnel is filled with air, which blows around the loop like a circular wind tunnel.

I don't know anything about fluid mechanics, but wouldn't there be some serious friction between the fast moving air and the tunnel wall? I'd be surprised if that resulted in less energy loss than a fast moving vehicle through static air, but perhaps someone with expertise about such things could chime in...

Re: Elon Musk to publish hyperloop design by August

#173

Post by dasloop » Tue, Jul 16, 2013, 9:44 AM UTC

omni wrote: post #86

dasloop wrote: post #55

Being cynical: promoting a futuristic tech to block the development of the proposed high speed rail.

If you have any evidence that Elon Musk of all people is deserving of such cynicism, I genuinely would like to see it.

I was cynical in a general way. A no sense without any evidence. Apologies for that.

Re: Elon Musk to publish hyperloop design by August

#174

Post by arkades » Tue, Jul 16, 2013, 11:31 AM UTC

disgruntledphd2 wrote: post #157

arkades wrote: post #85

Earlier quoted context omitted.

When (real) clinical trials are constructed against placebo, the statistical testing is constructed accordingly. If you were comparing against an existing drug, for instance, you might be testing to show it's equal-to or equal-or-better-than (perhaps your new drug is cheaper, or works on a different metabolic pathway, or has fewer side effects, that make it worth adding to the formulary if it otherwise has equal effe…

You know, upon thinking about it, I'm not sure that many (or even most) clinical trials use one-sided testing. It makes sense to do so, and would increase power for the particular side chosen, but I can't recall ever seeing it in a paper.

I've seen it in a couple of low-key (read: Non-FDA) trials, but for anything FDA-scale I think most people are wary about submitting studies that presume their subject can't possibly have -worse- results. If it's one of the early Phase 3's, it's just an unwarranted assumption, and people will be all over you for picking a more lenient study design without damn good reason to.

Re: Elon Musk to publish hyperloop design by August

#175

Post by tocomment » Tue, Jul 16, 2013, 12:19 PM UTC

InclinedPlane wrote: post #167

tocomment wrote: post #99

Is anyone still thinking it might be a launch loop?

A launch loop doesn't make sense, it's too risky (from a business sense) for this sort of project and too expensive too. Also, the obvious use of a launch loop is for launch, of course. Why serve a market where prices are cents per kilogram when you can serve a market where prices are hundreds of dollars per kilo? And with less capital investment too.

True, but maybe he needs a smaller scale, proof of principle launch loop before building a larger, faster? one for actual launching.