Schneibster

Phase is a meaningless word unless two waves are compared.

Never argue with a sound engineer about sound.

How about the giant fungus under (IIRC) Minnesota?

Later: did a little research, the one in the Northern Midwest has been eclipsed by one in Oregon:

http://en.wikipedia.org/wiki/Largest_organisms#Fungi

2400 years old. Hmmm. Aren't bristlecone pines older than that?

 

Thank you for your comments.

 

1) Phase.

 

Try the following experiment.

 

Take a loudspeaker and listen to it.

Now reverse the connections.

Can you hear any difference, the phase between the two connections is as far apart as possible?

 

You can also do this with a pair of loadspeakers, with the same result.

In fact this is incorrect. If you reverse the phase of one speaker of a stereo pair using a stereo source program, you will be able to hear the difference.

Furthermore, you can also hear the difference if you use headphones, in reversing left and right, or reversing the phase of either one alone.

This is standard audio engineering. I can present links to a couple good books on it, but personally I learned it by experimentation in the real world.

You can avoid this by reversing the phases of both speakers simultaneously.

All of this also applies to 5.1 and 7.1 systems. In fact, phase is even more important with such complex setups.

I know a man who thinks womens' college basketball is the ultimate distillation of the game. I'm not sure I disagree; I have rooted for the Stanford women numerous times. They nearly went to the Big Dance this year and they are perennially close. I spent a night on vacation once upon a time, with the Schneibsteress who is an inveterate sports fan, in the hotel room watching the Stanford game, Elite Eight or Final Four, I don't recall which, because they closed down the bar and turned off the TV before it was over. Furthermore, Naismith originally developed it for college. It's respectful of the game.

And I cheered myself hoarse for Brandy Chastain. And I think she should be able to take off her jersey if she wants. Girls with big knockers walk around in bikinis all the time. Pretty outrageous bikinis, on occasion, too. She was just being elated, and what she did justifies that. I would never criticize. I might get a bit sarcastic about it if she took off all her clothes. Just her sports jersey? Get over it. Good for her.

I didn't dare try acetone as it dissolves or softens too many plastics or, almost as bad, the plasticiser in some harder plastic. I think the wellies are pvc of some sort.

Yes, so I guessed. Good thing.

Glad it worked out the way you wanted.

Enthalpy you're being a one-trick pony: no nukes. This despite the fact you don't seem to actually understand how they work (you claimed the TWR wouldn't work based on the opinion of a single nuclear engineer who has a financial stake in it not working, for example).

Do you believe you can stop the Chinese and Indians from building power plants? (BTW I should note than when I say, "Indians," I always mean people from India, never First Americans.)

If not, then why are you insisting they build out coal-fired ones instead of nuclear? Do you not "believe in" global warming?

 

I would like to see the independently-gathered data please, this claim seems to be a bit, um, marketing-like...

It was in independent testing by two different firms. Whether it's still true in the last couple years I don't know; I bought a five year multi-system license and have never looked back. Got a pretty good price break from their standard thirty simoleons too. I have never had anything to complain about that turned out to be them. The one time they made a false positive on my system the next update (two days later) fixed it. That alone blows Kaspersky, Norton, and McAffee out of the water; their customer support all sucks. Maybe you're OK with waiting six months for your vendor to fix a false positive; I'm not. That's simple laziness and disrespect for customers. Eset is fast and it doesn't miss anything I've ever found.

I went to the testing firms to decide what antivirus to buy, not to the antivirus vendors to check their claims. I do not work for Eset or hold stock or know anyone who works there. Please don't make veiled accusations without evidence. It's impolite.

Not to mention, are you arguing about firewalls or antivirus?

You seem confused.

No.

Yes. This is how cosmologists say how long it's likely to be until the universe undergoes the Big Rip.

Remember though that the fact that we no longer feel its gravity doesn't mean the rest of the universe doesn't. In fact, somewhat more than a third of the visible universe still does; it hasn't disappeared over their horizon.

Be very, very careful saying the ear is not sensitive to phase, studiot. In fact, the ear is very sensitive to phase and uses it to provide direction information. That's the reason for all the intricate whorls and ridges in your external ear.

Furthermore, the cochlea has muscles that allow it to filter phases, and to filter frequencies. It is this that allows you to hear a voice even over background noise.

As far as the original OP, I agree with the majority of posters that this is destructive interference caused by the shape of the bell/chalice and present at certain spatial nodes and absent at others. I have experienced numerous similar effects while playing music, engineering musical recordings, arranging studios and live performance stage setups, and watching my home theater.

It is necessary to develop new intuitions, and the knowledge of when to use them.

The real world is considerably different than what we think we see. Newton realized that in the seventeenth century.

Energy can be light which has no mass (though it has momentum). It can also be the twisting or stretching of a rubber band (which are in different parts of the stress-energy tensor).

When the universe was first formed as we see it now, after the vacuum fluctuation and inflation, when the inflaton dumped its energy into the newly created universe and the Big Bang happened everywhere, there were all kinds of particles, but they were all in equilibrium. With such a high energy density, each particle lasted only a fraction of a nanosecond before it met an antiparticle and annihilated back into energy. But as the universe cooled, the particles started to last longer, and some of them were matter fermion particles like quarks or leptons, not energy boson particles like photons, colored gluons, or W and Z particles. Eventually the quarks mostly decayed into up and down quarks, and the leptons (except neutrinos) decayed into electrons. Why the up and down quarks were favored over antiups and antidowns is, as swansont intimates, still a matter of controversy among physicists. But that's what happened, beyond a shadow of doubt; everyone agrees on that, because it's what we've measured.

Once it had then all the newly formed nucleons (neutrons and protons, respectively two downs and an up and two ups and a down) associated with electrons and became atoms.

Then, because the pressure and density and temperature were still so high, about 1/4 of the hydrogen fused into helium (and incidentally also into a very small percentage of lithium, which is important because it indicates the exact conditions under which this all happened, as does the exact percentage of helium created).

The rest of the elements have been cooked up in the cores of stars, then spread across the universe by supernovae and by the enormous plumes of superheated gas that we have been recently observing connecting the galaxies, and galaxy clusters, and surrounding the superclusters of galaxies, that make up our universe.

I think this is a Pretty Good answer to your question, "where did matter come from."

Just to complete the picture, the flies are circling a piece of neutron star that takes up only a tiny space compared to the rest of the atom; if the electrons are flies in church the neutron star is the size of your fist. And that fist is where all of the mass of the atom is.

Snicker @ IANAM

Cheap paint thinner contains more fractions than proprietary ones, I would bet.

I'd've suggested acetone but I was pretty sure if they were miniature real wellies made with rubber it would melt them.

If I accept the IPCC's figures (although I think they have been stretched upwards as far as they will go) and still think that the small bit of warming they predict is going to be a nice thing and not a problem does that make me a sceptic, a denier or a realist?

 

The only humans who will be significantly adversely effected by global warming are, as far as I can see, those who own a ski chalet. It will be on the wrong mountain.

Actually changes in the climate will wreck the US breadbasket in the Midwest. It wouldn't be a problem to move to Canada except the dirt has all been scraped down to bare rock by the glaciers and pushed south. That's why there's lots of dirt in the Midwest. Oops.

So all of the US population in the Midwest will be unable to grow food any more.

Meanwhile, the sea level will be rising and the storms will be getting bigger and bigger on both coasts of the US. New York is history. So's most of the LA basin and a lot of Seattle. The California Central Valley will become a sea. Florida will be a series of undersea mountains, as will most of Texas and all of low-lying Louisiana.

And that's just in the US.

Meanwhile a quarter billion people in Bangladesh will die. Meanwhile all the Pacific islands will be inundated, except the mountain peaks like Mauna Kea. Meanwhile half a billion people will die in China and India. Meanwhile most of Pakistan's Punjab (one of the richest agricultural regions in the world) will be underwater.

I project excess deaths of 3 billion or more by 2100.

You could have a look at the arguments of the proponents of the travelling wave reactor. These people knew very little about nuclear energy. They just said "it would be fantastic", not a word about "how" (because, anyone knows for long the potential advantages, only they didn't understand the difficulties), and this was enough to pull money from Bill Gates.

 

It's impossibility results from detailed figures, which aren't even well accessible to hand computations. So there's no simple qualitative answer. But consider that any breeder is seriously difficult to bring to plutonium regeneration, using optimum conditions everywhere: shape, size, concentrated military plutonium fuel - and then the breeding figure is like one dot zero something. The travelling wave reactor would be a breeder, but under very unfavourable conditions. No chance to run.

 

Then, you may read the initial proposal by the crooks: they wanted to ignite the travelling wave using uranium - which clearly tells they don't understand the topic.

 

I wonder: how do you decide what (or who, which is a less good choice) you want to believe? The ones you read first? Or the proposal that fits your desires better? Be reassured that it's not my personal opinion: the whole nuke community considers for decades the travelling wave reactor as an obvious impossibility.

Unfortunately my research indicates that you are presenting the narrow viewpoint of one nuclear engineer, Kirk Sorenson. The community does not agree. Also, Sorenson's firm is in direct competition with TerraPower, which unfortunately makes him a biased source with a financial interest in the outcome of the argument. (For observers: TerraPower is the company Enthalpy is complaining about getting money from Bill Gates.)

Furthermore you have not addressed the consumption of existing nuclear waste, which can be accomplished with no other type of reactor at all. Do you prefer keeping it in a mountain near your town, or in the pools next to the reactors where it can participate in the next nuclear accident like it did at Fukushima? There are already thousands of tons of it. What's your solution?

On edit: What's the matter with using ²³⁵U to start the reaction?

I was right. You are confusing the Dirac Lagrangian with the Dirac field.

IIRC it's about 20kt/gram of annihilated matter (so a half gram of antimatter would annihilate a half gram of matter, for a total of 1g annihilated). I don't remember the figure in joules but there are numerous conversion calculators on line. It's on the close order of 10 or 20 tJ. It's about 90 tJ.

Did you mean "joules" instead of "grams" above? Later: No, you can't possibly. The correct value for the energy of a gram of matter is 89,875,543,056,250 joules or 21.480770329 kilotons. That's about 90 trillion joules, or 21 kilotons in nuclear explosive terms.

You can lead a cat to food but you can't make him eat.

That's a shame. Unfortunately the only alternative is to label them all psychotics suffering from delusions. That is in fact the case, but you won't get far telling her so.

Snicker @ "LASER" Backronym.

Meanwhile, I'd expect a random flat surface reflection to be fairly limited in angular scope even at that long a distance.

Moontanman, that's tough, but if you can't get someone to believe molecular biology after all we can do, including create new living species in the lab, not to mention organisms that are alive but are clearly not anything that ever evolved on Earth, then your friend insists on ignoring reality and you should tell her so. She's welcome to deny whatever she wants, but that doesn't make it real and you should tell her so, and tell her of your concerns that she is ignoring reality.

You will never convince her but you can at least make her think about it.

The first scenario is that Neandertals occasionally interbred with modern humans after they migrated out of Africa. The alternative scenario is that the humans who left Africa evolved from the same ancestral subpopulation that had previously given rise to the Neandertals.

Dr. Lohse has found a subtle genetic method for confirming the difference between the first and second scenarios above.

This method has positively ruled out the second scenario. It is certain now that Homo Sapiens Neanderthalensis and Homo Sapiens Sapiens interbred on occasion, and modern humans of all so-called "races" have inherited genes from these occasions.

The press release is here; I look to the geneticists among us to check out the scholarly paper (linked in the press release) and tell us all what we're looking at in terms of the details of the new method.

I expect it was all the footage the reporter on FP could find on short notice. They're going through a "Hey, look at all these awesome graphics 'n' stuff on this new Internet thingie!!" phase right now. I have to close their window and only open it when I want to surf them so they don't overwhelm my CPU.

I've summarized our results back there (I'm a full subscriber to FP) and we'll see what I hear back.

Meanwhile I also mentioned "no explosive magazine risk" as a possible advantage; thanks you guys.

And I have thought about the range, which is impressive to say the least. They can hit anything in the littoral. I think the most important thing is how many projectiles they can put on target before the target can react. Even if they're small, any aircraft hit is down for days. Furthermore, there is the durandal effect on the runways; planes are no good if you can't launch them and you can't launch them if they're full of holes. If they can put hundreds of these on target in minutes, it will be like lightning raining down from Gawd guided by satellite.

Another important point is that they can put small force on target a hundred miles away. Never mind drones, these things are almost as small as Hellfire missiles drones use. And the drone's data showing the target location can be fed to this gun, and a projectile can land a hundred miles away that only takes out one or two rooms in a house, instead of the whole block. And no explosives.

It's plausible. Since I'm not being paid I'll leave it to a real mathematician (and there are some here) to comment on whether it will actually work.

If it does work, then if you can design the algorithm right in terms of primitives you'll get something that's ripe for compiler optimization in a RISC.

This is an assembly/machine language level optimization, however, something you do in a compiler, not in, say, C or Fortran.

That's my opinion as a CS. You should wait for a mathematician to confirm the algorithm works.