Anechoic

48 ms·

451.
by Anechoic 13y ago
Take note that Musk's Hyperloop prototype was created on a 3-D printer, What prototype? Did Musk actually show a model?
452.
by Anechoic 13y ago
Release the gate security video and we can make our own determinations.
453.
by Anechoic 13y ago
This post is a perfect example of what I'm talking about.
454.
by Anechoic 13y ago
Everyone, including(maybe even especially) black americans, should watch this speech There is nothing in that speech which is not already common-knowledge or thoroughly discussed among blacks.
455.
by Anechoic 13y ago
is mainly a phenomenon found in a sub-culture of black America. You only have to watch prime-time television to know that phenomenon is common amongst many demographics. Anyone who has been immersed in an African-American community for a
456.
by Anechoic 13y ago
* This is elementary statistics based on data collected by the FBI. If this problem [..] can't be discussed in an honest fashion due to political organizations which will threaten politicians with boycotts/villification/etc d
457.
by Anechoic 13y ago
On a related topic: If you're in the Denver area this week, feel free to drop in on a Free Public Workshop on Noise in Communities and Natural areas: http://www.naturalquietworkshop2013.org/ which is being held in conj
458.
by Anechoic 13y ago
and have observed that my current office sometimes averages 75-80 db. Is that A-weighted ("dBA") or linear? If that result is A-weighted, that noise level is dangerously loud - it may meet OSHA but it's almost certainly c
459.
by Anechoic 13y ago
Better sound insulation can help reduce the noise level from external sources inside a home, but 1) does nothing for outdoor areas of your home (a patio or porch for example), and 2) becomes completely ineffectual if you open a window.
460.
by Anechoic 13y ago
There is (was?) a privately-funded project that was well into the engineering phase ( http://www.xpresswest.com ) but they needed a Federal loan to make the project feasible and FRA recently put the kibosh on the loan: http:&#x2F
461.
by Anechoic 13y ago
The whole problem is this is a proposal. It's not even at the research stage. As such, all we can do is speculate to its advantages and/or disadvantages and a lot of questions go answered. If Musk (or anyone else) wants to address
462.
by Anechoic 13y ago
Your last paragraph seems to say that we don't want accurate estimates because then we might not do the projects. No, my last paragraph says we don't want ultra-conservative estimates because we would definitely not do the proje
463.
by Anechoic 13y ago
I ask because my perception in reading your comments is that theory translates nicely to real-world practice (which is also what I get from reading the Hyperloop white paper), when the reality IME is that it almost never does. For example:
464.
by Anechoic 13y ago
What is your experience with large capital projects?
465.
by Anechoic 13y ago
I think you can fit a 7.5ft diameter tube inside an 8ft square box. You are not going to give yourself 6-inches of clearance for a component that weighs (using your numbers) 19.2 tons, that pipe is going on a flatbed. You also have to all
466.
by Anechoic 13y ago
why do they always happen to always be inaccurate on the bad side these days? I don't have time to find it right now, but I remember reading a study a few years ago that showed most projects to in fact come in on time and on budget
467.
by Anechoic 13y ago
Building metal tubes is one thing. Actually getting permission from abutters to install those metal tubes on/near their property and then dealing with the varying field conditions is a whole 'nother problem.
468.
by Anechoic 13y ago
Rail installation costs are no joke due to the need to precisely align horizontally and vertically the two rails. The hyperloop sections would also need to be precisely aligned. You can make tube in 50ft sections and ship them via truck
469.
by Anechoic 13y ago
I think we have a pretty good handle on both by now In terms of a specific project, not really. Look at everything that goes into an environmental study: watershed/water quality, affected wildlife/endangered species, noise &
470.
by Anechoic 13y ago
the criticism amounts almost entirely to basic arithmetic and comparisons to existing systems that are built on rather different principles. But many of most important (and show-stopping) principles involved are the same, and those are
471.
by Anechoic 13y ago
That means the system can be designed to support just one of them per pylon. The capacity of the structure is not just limited to the weight of the revenue vehicles, the structure needs to handle other loads it may encounter over the its
472.
by Anechoic 13y ago
they will do the same thing with the hyperloop as with the maglev (ignore it). The US government didn't ignore maglev, they did a lot of study (including paying for me and my boss to travel to Germany to perform noise and vibration m
473.
by Anechoic 13y ago
No. That would only be true if the vehicle was buoyant.
474.
by Anechoic 13y ago
and then all the test tracks, e.g. the transrapid in germany ... which closed a few years ago :(
475.
by Anechoic 13y ago
Vibration from trains is proportional to the unsprung weight of the vehicle (basically the axle, wheels and traction motors) rather than the vibration of the whole vehicle (which is isolated by the primary and secondary train suspensions).
476.
by Anechoic 13y ago
Yes, rather than a line-source, you have multiple incoherent point sources, but those point sources are being excited along a line at a rate faster than the shear wave speed. So yes, it somewhat different, but also similar. A test segment w
477.
by Anechoic 13y ago
The weight of the track ballast alone is more than that. ? You don't need to use ballast & tie track on elevated structure, in fact it's rare to do so on modern rail structures.
478.
by Anechoic 13y ago
No. Well, I suppose you could design an active vibration system to (almost) completely cancel the vertical vibration motion, but know you're talking about a powered system in each pylon of incredible complexity. Passive resilient syste
479.
by Anechoic 13y ago
Putting the railway or tubes on pylons would give you an opportunity to dampen or otherwise transform those vibrations wouldn't they? Maybe, maybe not. Guideway supports (pylons) are typically founded into the bedrock which does redu
480.
by Anechoic 13y ago
I don't believe that an experimental tube is going to be somehow magically cheaper and easier to route and build than train tracks. Do you really think the special interests that are making HSR so difficult and expensive would say,

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