"At high speeds this precooler cools the hot, ram compressed air leading to an unusually high pressure ratio within the engine. The compressed air is subsequently fed into the rocket combustion chamber where it is ignited with stored liquid hydrogen. The high pressure ratio allows the engine to continue to provide high thrust at very high speeds and altitudes. The low temperature of the air permits light alloy construction to be employed which gives a very lightweight engine — essential for reaching orbit." —WikiPedia

>> ^deathcow:

They must be talking about using space to get from Europe to Australia, as friction is a real bitch otherwise.

Possibly, although I think its somewhat more likely they'd just be flying at very high altitudes where the atmosphere is very thin.


From what I read on wiki it seems the engine is basically rocket/turbine hybrid. They use liquid hydrogen as fuel but instead of storing oxygen they suck it out of the air. The problem the cooling fixes seems to be related to supersonic airflow. Turbine engines need subsonic airflow to work properly so they use a ram, a cone on the front of the turbine, to slow the airflow before it enters the engine. This heats the air entering the engine up a lot, hot air takes up more space and so its difficult to get enough oxygen to the hydrogen fuel. Cooling the air after it passes over the ram lowers the air pressure and allows more air to pass through the engine. Scramjets approach this problem a different way in that they can operate with supersonic airflow, although they have the limitation of not working subsonic.

Anyway. Its quite fascinating. I don't think we'll be seeing commercial aircraft using this technology anytime soon though. I'd be pretty nervous about flying on something that is basically rocket powered. Space tourism maybe? If it can fly to high altitudes with the turbine and then switch seamlessly to using onboard oxygen it could be a much more efficient way of getting into space without using onboard oxygen the whole way up.

Oh, and RIP Concorde. I used to go to school under their flightpath out of Heathrow. 11am on Wednesdays they used to rattle the windows passing over.

Congratulations! Your comment has just received enough votes from the community to earn you 1 Power Point. Thank you for your quality contribution to VideoSift.

This achievement has earned you your "Silver Tongue" Level 2 Badge!

Don't have to watch the video. Been dealing with second and third degree burns on my arms from hot oil. And I got layed off sooo, yay! No health insurance!

The real fun comes when you scrub the layers of dead skin on the wound and then pour hydrogen peroxide over it. Mmmm...good stuff.

@MilkmanDan When it comes to mercury I'm of the opinion that the educational benefit of playing with it is fairly slim compared to the danger, so why risk it.

On the other hand, my kids are doing awesome things in science now that I never did at their age in school (grade 2/3/prep). They've had dry ice to see what it does (of course, I've done that with my kids a number of times too, too much fun), they've had balloons filled with hydrogen exploded in class, and a few other things I've forgotten. The main thing is that I thought that they may well be limited in what cool science they get to do at school, but at least at our kid's one they seem to be doing plenty of awesome stuff.

Safe nuclear refers to many different new gen4 reactor units that rely on passive safety instead of engineered safety. The real difference comes with a slight bit of understanding of how nuclear tech works now, and why that isn't optimal.

Let us first consider this, even with current nuclear technology, the amount of people that have died as a direct and indirect result of nuclear is very low per unit energy produced. The only rival is big hydro, even wind and solar have a great deal of risk compared to nuclear as we do it and have done it for years. The main difference is when a nuclear plant fails, everyone hears about it...but when a oil pipeline explodes and kills dozens, or solar panel installers fall off a roof or get electrocuted and dies...it just isn't as interesting.

Pound per pound nuclear is already statistically very safe, but that isn't really what we are talking about, we are talking about what makes them more unsafe compared to new nuclear techs. Well, that has to do with how normal nukes work. So, firstly, normal reactor tech uses solid fuel rods. It isn't a "metal" either, it is uranium dioxide, has the same physical characteristics as ceramic pots you buy in a store. When the fuel fissions, the uranium is transmuted into other, lighter, elements some of which are gases. Over time, these non-fissile elements damage the fuel rod to the point where it can no longer sustain fission and need to be replaced. At this point, they have only burned about 4% of the uranium content, but they are all "used up". So while there are some highly radioactive fission products contained in the fuel rods, the vast majority is just normal uranium, and that isn't very radioactive (you could eat it and not really suffer any radiation effects, now chemical toxicity is a different matter). The vast majority of nuclear waste, as a result of this way of burning uranium, generates huge volumes of waste products that aren't really waste products, just normal uranium.

But this isn't what makes light water reactors unsafe compared to other designs. It is all about the water. Normal reactors use water to both cool the core, extract the heat, and moderate the neutrons to sustain the fission reaction. Water boils at 100c which is far to low a temperature to run a thermal reactor on, you need much higher temps to get power. As a result, nuclear reactors use highly pressurized water to keep it liquid. The pressure is an amazingly high 2200psi or so! This is where the real problem comes in. If pressure is lost catastrophically, the chance to release radioactivity into the environment increases. This is further complicated by the lack of water then cooling the core. Without water, the fission chain reaction that generates the main source of heat in the reactor shuts down, however, the radioactive fission products contained in the fuel rods are very unstable and generate lots of heat. So much heat over time, they end up causing the rods to melt if they aren't supplied with water. This is the "melt down" you always hear about. If you start then spraying water on them after they melt down, it caries away some of those highly radioactive fission products with the steam. This is what happened in Chernobyl, there was also a human element that overdid all their safety equipment, but that just goes to show you the worst case.

The same thing didn't happen in Fukushima. What happened in Fukushima is that coolant was lost to the core and they started to melt down. The tubes which contain the uranium are made from zirconium. At high temps, water and zirconium react to form hydrogen gas. Now modern reactor buildings are designed to trap gases, usually steam, in the event of a reactor breach. In the case of hydrogen, that gas builds up till a spark of some kind happens and causes an explosion. These are the explosions that occurred at Fukushima. Both of the major failures and dangers of current reactors deal with the high pressure water; but water isn't needed to make a reactor run, just this type of reactor.

The fact that reactors have radioactive materials in them isn't really unsafe itself. What is unsafe is reactor designs that create a pressure to push that radioactivity into other areas. A electroplating plant, for example, uses concentrated acids along with high voltage electricity in their fabrication processes. It "sounds" dangerous, and it is in a certain sense, but it is a manageable danger that will most likely only have very localized effects in the event of a catastrophic event. This is due mainly to the fact that there are no forces driving those toxic chemical elements into the surrounding areas...they are just acid baths. The same goes for nuclear materials, they aren't more or less dangerus than gasoline (gas go boom!), if handled properly.

I think one of the best reactor designs in terms of both safety and efficiency are the molten salt reactors. They don't use water as a coolant, and as a result operate at normal preasures. The fuel and coolant is a liquid lithium, fluoride, and beryllium salt instead of water, and the initial fuel is thorium instead of uranium. Since it is a liquid instead of a solid, you can do all sorts of neat things with it, most notably, in case of an emergency, you can just dump all the fuel into a storage tank that is passively cooled then pump it back to the reactor once the issue is resolved. It is a safety feature that doesn't require much engineering, you are just using the ever constant force of gravity. This is what is known as passive safety, it isn't something you have to do, it is something that happens automatically. So in many cases, what they designed is a freeze plug that is being cooled. If that fails for any reason, and you desire a shutdown, the freeze plug melts and the entire contents of the reactor are drained into the tanks and fission stops (fission needs a certain geometry to happen).

So while the reactor will still be as dangerous as any other industrial machine would be...like a blast furnace, it wouldn't pose any threat to the surrounding area. This is boosted by the fact that even if you lost containment AND you had a ruptured emergency storage tank, these liquid salts solidify at temps below 400c, so while they are liquid in the reactor, they quickly solidify outside of it. And another great benefit is they are remarkably stable. Air and water don't really leach anything from them, fluoride and lithium are just so happy binding with things, they don't let go!

The fuel burn up is also really great. You burn up 90% of what you put in, and if you try hard, you can burn up to 99%. So, comparing them to "clean coal" doesn't really give new reactor tech its fair shake. The tech we use was actually sort of denounced by the person who made them, Alvin Weinberg, and he advocated the molten salt reactor instead. I could babble on about this for ages, but I think Kirk Sorensen explains that better than I could...hell most likely the bulk of what I said is said better by him



http://www.youtube.com/watch?v=N2vzotsvvkw

But the real question is why. Why use nuclear and not solar, for instance?

http://en.wikipedia.org/wiki/Energy_density

This is the answer. The power of the atom is a MILLION times more dense that fossil fuels...a million! It is a number that is beyond what we can normal grasp as people. Right now, current reactors harness less that 1% of that power because of their reactor design and fuel choice.

And unfortunately, renewables just cost to darn much for how much energy they contribute. In that, they also use WAY more resources to make per unit energy produced. So wind, for example, uses 10x more steal per unit energy contributed than other technologies. It is because renewables is more like energy farming.

http://videosift.com/video/TEDxWarwick-Physics-Constrain-Sustainable-Energy-Options


This is a really great video on that maths behind what makes renewables less than attractive for many countries. But to rap it up, finally, the real benefit is that cheap, clean power is what helps makes nations great. There is an inexorable link with access to energy and financial well being. Poor nations burn coal to try and bridge that gap, but that has a huge health toll. Renewables are way to costly for them per unit energy, they really need other answers. New nuclear could be just that, because it can be made nearly completely safe, very cheap to operate, and easier to manufacture (this means very cheap compared to today's reactors as they are basically huge pressure vessels). If you watch a couple of videos from Kirk and have more questions or problems, let me know, as you can see, I love talking about this stuff Sorry if I gabbed your ear off, but this is the stuff I am going back to school for because I do believe it will change the world. It is the closest thing to free energy we are going to get in the next 20 years.

In reply to this comment by ReverendTed:
Just stumbled onto your profile page and noticed an exchange you had with dag a few months back.
What constitutes "safe nuclear"? Is that a specific type or category of nuclear power?
Without context (which I'm sure I could obtain elsewise with a simple Google search, but I'd rather just ask), it sounds like "clean coal".

So by the time this montage is done, women will have learned that H is the chemical symbol for the element Hydrogen. 91 more to go!

Looks like @kceaton1's getting serious.

You may not speak out but i've decided to. If anyone is concerned about the seemingly unfair statements i make about shinyblurry then my comment section can show the proof. I have engaged him in discussion a number of times of science/theism, and the results are poor. He doesn't offer you the same respect he expects you to give him, i find him egotistical and obnoxious and completely uninterested in serious discussion. Read my discussions with him if you don't believe that - there's proof which is the test of any theory as we all know.

People like shinyblurry don't even realise that their zealotism drives people away from the religion.

Let me make a statement regarding the big bang theory. Firstly, all scientific theories are put in place to explain the facts. A theory takes everything we know, balls it up into a bunch of connections, and offers us a way of understanding that phenomenon. The big bang theory is not "complete", that is why it's still an active field of study. There are so many scientists right now trying to improve on theories that it's hard to even imagine.

You read a web page like that - almost entirely signed by scientists from the US and mostly "independent researchers"? And suddenly you think you know about the big bang. And in it one person suggests the idea that rigidly adhering to old forms is harmful to scientific advancement, but you take it to mean something else as far as i can tell - shame on you.

The big bang predicts the initial distribution of elements that we see reflected in the universe today - mostly hydrogen, a bit of helium and trace other elements. It actually predicts using only PROVEN SCIENTIFIC PRINCIPLES (that are testable to anyone on earth) what time and at what temperature different particles were able to form. From that, it predicts what chemical composition the universe has, and finds that it's in agreement. Do you even realise the significance of that? I don't think you do, your brain has been trained by religion to look for things like that and see only design. And that's also why you can't understand scientific theories. You really need to open your mind to how other people think, blurry, and i mean that with kindness.

Do you really think the big bang is so far away from the truth, in your ignorance? Have you looked at it in the kind of depth you need to to understand it? If not, i kindly ask that you stop spouting rubbish in the same way i don't go about trashing your unfounded, ungrounded theories every time you mention theism.

i didn't intend to speak out on @kceaton1's behalf, but i'm pretty sick of blurry canvassing for converts with misinformation myself. His links and statements provide nothing of substance to the argument. It doesn't matter what religion kceaton is, as a theist yourself i'm surprised you act cocky about another's choice of religion. Doesn't your religious claptrap say something like do unto other as you would have them do unto you? In my opinion under your own religion you will be going to hell for being so manipulative and insulting to others.

>> ^kceaton1:

>> ^shinyblurry:
That's quite a rant, Kceaton. Unfortunately, you cannot use the light travel time problem to falsify YEC. The SBB model also has a light travel time problem, specifically the horizon problem. Check out what some scientists published in New Scientist Magazine:
http://www.cosmologystatement.org/
I'm sorry you were indoctrinated into the Mormon church. My heart goes out to you, but you've thrown away the baby with the bathwater. It isn't too difficult to falsify the Mormon God, but neither does that make atheism the natural conclusion.
>> ^kceaton1

One:
I've known about this study since day one, does it surprise me, hahahahahaha. I think most people are morons. NO IT DOESN'T! I think we have one of the worst educations systems in the world, you may think your belief driven gospel knowledge may keep you safe, flying up there in the sky, BUT I'll take a damned engineer EVERYDAY over your damned God!
Two:
About my past. This is the THIRD time you've said this same thing. This is borderline abuse, FUCK YOU! Get off your high horse your are not an immortal moral high judge sent here to Earth to tell us what was a wrong or "sorrowful" mistake. I'm sorry, I'm being really damned aggressive right now, but I'm tired of your cockeyed charades and your imperative to make sure every Mormon that is or ever was KNOWS how "sorry" you are for them.
---
I'm tired of the targeted trolling!
That also means I will never qualify your "horizon" crap with a response, because it doesn't deserve one. I know this came off rude so sorry for that, on the other hand it was suppose too.

OMG, We've ALL been discovered...

What Should I Consider Suspicious?

People Who:
- Are overly concerned about privacy, attempts to shield the screen from view of
others
- Always pay cash or use credit card(s) in different name(s)
- Apparently use tradecraft: lookout, blocker or someone to distract employees
- Act nervous or suspicious behavior inconsistent with activities
- Are observed switching SIM cards in cell phone or use of multiple cell phones
- Travel illogical distance to use Internet Café

Activities on Computer indicate:
- Evidence of a residential based internet provider (signs on to Comcast, AOL,
etc.)
- Use of anonymizers, portals, or other means to shield IP address
- Suspicious or coded writings, use of code word sheets, cryptic ledgers, etc.
- Encryption or use of software to hide encrypted data in digital photos, etc.
- Suspicious communications using VOIP or communicating through a PC game

Use Computers to:
Download content of extreme/radical nature with violent themes
- Gather information about vulnerable infrastructure or obtain photos, maps or
diagrams of transportation, sporting venues, or populated locations
- Purchase chemicals, acids, hydrogen peroxide, acetone, fertilizer, etc.

Download or transfer files with “how-to” content such as:
- Content of extreme/radical nature with violent themes
- Anarchist Cookbook, explosives or weapons information
- Military tactics, equipment manuals, chemical or biological information
- Terrorist/revolutionary literature
- Preoccupation with press coverage of terrorist attacks
- Defensive tactics, police or government information
- Information about timers, electronics, or remote transmitters / receivers

Here is the Pamphlet: http://publicintelligence.net/do-you-like-online-privacy-you-may-be-a-terrorist/

This is an older pamphlet. It's a scanned photocopy, it's hard to tell if this is official or not but several sites seem to have it posted: http://welfarestate.com/pamphlet/

>> ^GeeSussFreeK:

>> ^papple:
A part of me thinks that this is a beautiful piece of engineering, but another part of me feels sad that it'll only be used to drop bombs on people.

It is actually a spy plane, even so, any R&D you can point towards developing a hydrogen economy (provided we find good ways to produce hydrogen), the better!


Spy planes are used to spot places to drop bombs on them as well, it's a first strike weapon, like a "Missile Defense Shield."

>> ^papple:

A part of me thinks that this is a beautiful piece of engineering, but another part of me feels sad that it'll only be used to drop bombs on people.


It is actually a spy plane, even so, any R&D you can point towards developing a hydrogen economy (provided we find good ways to produce hydrogen), the better!



One of the killer apps of the particular flavor of nuclear I am interested in deals with high heat electrolysis which could help in the transition to a hydrogen economy. Technologies that aid in hydrogen production will also most likely be suited for desalinization of water, which could be of great need if warming of the earth changes regional rain patters.



http://nuclear.energy.gov/genIV/documents/gen_iv_roadmap.pdf

Yeah, blame the guy with the cigarette, not the guy who filled party balloons with fucking hydrogen.

>> ^zor:

>> ^sillma:
What a waste of perfectly good helium.

Right. Helium is not a good choice. Should have used hydrogen because it's renewable. They can use the energy to make more from water and if it explodes no harm no foul since there are no people on board.


But a 35 foot wide burning anything crashing to the earth has got to be bothersome.

>> ^sillma:

What a waste of perfectly good helium.


Right. Helium is not a good choice. Should have used hydrogen because it's renewable. They can use the energy to make more from water and if it explodes no harm no foul since there are no people on board.

Tags for this video have been changed from 'coal, mining, asphyxiation, amok time sounds' to 'coal, mining, asphyxiation, amok time sounds, h2s, hydrogen sulfide' - edited by BoneRemake