1. The density of a liquid is dependent not only on the size of the molecules in it, but on their mass, and on the space between them (that's why hot water is less dense than cold water - on average there is more space between hot water molecules than cold).
Yes - I was assuming that temperature is fixed and very low (as needed to liquify hydrogen.
2. Atomic size is not constant. It does change (not monotonically) with atomic number. You can see how here: Atom radii.
Yes - but slowly. Thank your for the link, it is actually closer than I thought: r_H=53pm, r_B=87pm, r_O=48pm.
This is as opposed to increasing the radius proportionately to the cubic root of the atom number.
3. ALL molecules have "overlapping" electronic orbitals if you mean that the atoms are sharing some electrons between them - that's what makes them molecules. Not sure what your point is here.
What I meant is that the volume of the molecule is smaller than sum of volumes of individual atoms. In particular, I would expect oxygen to strip the electron from the hydrogen completely so that the size of the molecule would be not much larger than the size of a single oxygen atom.
4. Deuterium has about the same atomic volume as hydrogen (where'd you get 40% less?) but the atomic mass is naturally about doubled (1 proton +1 neutron vs 1 proton - and almost all the mass is in the nucleus), thus the density of D2 is twice that of H2.
Actually I was wrong - by that reasoning the volume should be smaller almost by a factor of 3 (2^1.5), however I would expect electrostatic repulsion to kick in before this factor is reached.
5. The density difference between D2 and H2 is of no practical value for fuel cells. It'd be worse to use D2 since it's heavier and the increased density comes from the nuclei, not from an increased number of atoms per volume. And you're not getting energy out of the nucleus but out of the rearrangement of chemical (electronic) bonds. At least until we start talking about nuclear-powered cars. Then count me in!
That was just an example. I thought by density we meant energy content per volume, not per unit of mass ? Since for a car mass is of lesser concern than volume. As for nuclear powered cars - me too:)
How does a mixture of Borohydride(not pure hydrogen) and Water(which is already only 2/3 hy
drogen) end up being more hydrogen than Liquid Hydrogen? Isn't Liquid Hydrogen pure hydrogen?
This is actually a very interesting question. Let's see if I can get this right:
Each atom has positively charged nucleus and a bunch of electrons, so the whole thing is neutral. The more electrons we have the bigger the attraction force. Thus, while the diameter of the atom grows with element number it does so only slowly and one can consider atom size to be roughly constant - especially for elements like H, O, B.
What determines the volume of the liquid is then the size of the molecules composing it - and a molecule like H2O has some parts of the electron shells overlapping.
However, in case of pure hydrogen it is so light that besides pure electrostatic repulsion one also has uncertainty principle - the mass of H2 is so small that it cannot be within a very small volume or it would have to possess a large momentum (and thus be very hot).
If I am right it would mean that deuterium would have 40% less volume for the same number of atoms as hydrogen - but I don't have a ready reference - crosscheck anyone ?
Civilization is cool for me because it takes some thinking, is quite entertaining, but doesn't cause issues with hand overuse. It's a hard formula to match.
Civilization is probably the only game with both graphics and moderately sophisticated AI and having random maps that actually matter.
In most other graphical games either AI is non-existent, or trained on a small set of maps - often both.
Why there is no fantasy-themed game with sophistication of Civ is beyond me..
Good for some situations, not a good plan when downtime costs you money. That's when the quality and maint services of the large vendors pay off.
That's the ironic part - switching over to a spare is faster than even a 1-hour response plan (if they sell such). And most of the medium to high end hardware that assures reliability (like hardware RAID cards) can be purchased without going through one of the big vendors.
I want you to find me a vendor with even decent warranty support who can build a 1U opteron with the SAME specs as a sun, IBM or HP for half the price.
I've been using PCs for everyone recently and they are pretty good though not the least expensive out there. The good part is that they preinstall Linux and make sure it works - some of the more expensive hardware I never had any experience with.
Also, as far as support goes, if the price savings are big enough (say 50%) one can just ignore hardware breaking down and replace it with a new box. Works well for general purpose compute needs.
Then again, these days it's rare to need the kind of hardware Sun or HP puts out. Several quality Opteron boxes from IBM running FreeBSD or Linux can provide the same level of service and the same reliability as a large Sun or HP system, and often at a far lower cost.
And even lower if instead of buying from IBM one uses a local computer shop. Last time I looked at IBM's website one could buy two generic boxes for the price of one that IBM sells, especially if one wants to max out the RAM.
Not that journalists haven't been known to manipulate a few words here and then, but these
clarifications just do not sound as a solid rebuttal at all - more like politics.
They dispute the attribution of the words, rather then their content and, at that, take care not to explicitly say "I really think the reverse of what was printed in the article".
Eliminating politics by refusing to actively participate in them!
What an impressive joy to read about the man. He helps build my faith in humanity.
2 people out of how many billions ? You, my friend, are an optimist.
I know some other nice people, but my point still stands - a handful of diamonds scattered on the beach will not make it sparkle - especially after several tides passed through.
Now, if you had reason to believe that humans improve as a species and in 100 years we can expect everyone to be at least that nice, that would be a completely different discussion..
Re:SQL book recommendation?
on
Pro MySQL
·
· Score: 1
MySQL is a (low end) database product. SQL is a language. Somehow, I doubt that a book covering a certain product is appropriate for somebody wanting to learn a lanugage.
I actually misspelled, the book name is "pocket sql" or something like that, it describes sql syntax specific to sql server, oracle, db2 and mysql.
As for "low end" this is very relative. I am crunching through.7 TB of data sitting in MySQL right now and it is quite efficient. In particular, if one were to construct a metric like database_ops/$$ then it is not exactly obvious which DB will come out on top - not needing to count the licenses one has make for much easier deployment on clusters.
An free software product with well-understood design and performance and unrestricted scalability is often the only answer to a high-end problem.
Re:SQL book recommendation?
on
Pro MySQL
·
· Score: 1
If you are just starting out with SQL, what book(s) would those familiar with it recommend?
And besides, yes, name is nice, but could they instead have a short description of major design choices they are considering ? Or why a particular characteristics (mass, size, shape) were settled on ?
Come on, "science" article that talks about a name choice - get a grip !
When that happens (if, in fact, it ever does, but I doubt), just don't buy the damned computer. That's Linus' position. The company will go out of business, and all the foaming mouth OSS zealots will be happy for another week.
On the other hand, if the company making the computer sells a bunch and has lots of happy customers-- great! They're making money, your software is getting exposure, it gives more choice to users, and people are all-around winners. If those people want to modify the software, they're still free to do that, they just have to buy another computer to run it on.
Unfortunately, it does not work like this anymore - if it ever did.
The world is global and business is getting increasingly efficient at monopolizing entire markets, let alone niche products.
This is a natural thing - as the technology progresses the lifetimes of the individual products are shrinking.
It is not efficient to build a lasting business on new products which are not likely to be in use in 10 years.
Rather, a common strategy is to achieve an established position in the market as fast as possible and then exchange it for capital - usually through sale of the company. The acquirer often specializes in maximizing short-term profit from established market.
A company with a DRM locked-in computer will attract more capital in the market due to perceived solidity of their "intellectual" property - as opposed to the company that plays by the rules and sells unlocked computers.
This extra capital can be used in a number of ways to squeeze out competitors - for example by launching frivolous lawsuits.
In other words, if you give a freebee (in the form of not enforcing spirit of GPL) to those that tend to abuse it one should not be surprised that they win.
What about when that scum sells that computer at a loss (ie. it costs $250+ to manufacture). Or what if they just give it away?
This probably isn't a far-fetched case. So is taking a loss on hardware to recoup your money on software evil?
I am glad you see my point.
What GPL does is break down the barriers separating passive users that push on buttons from active contributors to free software community. A person pushing buttons and thinking "I wish this worked slightly differently" can decide to open up the source file, make a change and try it out. The free availability of development tools and source code have seen to that.
What lock-in does is remove that choice from the user - and why exactly should the open source developer be interested in that ? They get no compensation from the distributor, they cannot sell support because the software does not allow patches to be applied and they don't get contributions back from users of locked-in platform.
Lock-in via DRM software is a way for an unscrupulous person to put a tax on the network effect that have lead to the success of free software.
The impetus to make a profit (and its associated compromises) isn't sitting well with true believers in free software.
This has nothing to do with not letting someone else make a profit and has all to do with not letting someone else lock you into some restricted platform and extort all they can get away with.
In response to grandparent, GPLv3 will become very relevant when you see some scum
mass produce a $150 computer with GNU/Linux that is cryptographically locked and then sell $10 "extension" cartridges with popular free software, in the same way that Sony locks its gaming consoles.
GPL is about freedom to modify and share code and DRM implementations take away your ability to modify your software.
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1. The density of a liquid is dependent not only on the size of the molecules in it, but on their mass, and on the space between them (that's why hot water is less dense than cold water - on average there is more space between hot water molecules than cold).
Yes - I was assuming that temperature is fixed and very low (as needed to liquify hydrogen.
2. Atomic size is not constant. It does change (not monotonically) with atomic number. You can see how here: Atom radii.
Yes - but slowly. Thank your for the link, it is actually closer than I thought: r_H=53pm, r_B=87pm, r_O=48pm.
This is as opposed to increasing the radius proportionately to the cubic root of the atom number.
3. ALL molecules have "overlapping" electronic orbitals if you mean that the atoms are sharing some electrons between them - that's what makes them molecules. Not sure what your point is here.
What I meant is that the volume of the molecule is smaller than sum of volumes of individual atoms. In particular, I would expect oxygen to strip the electron from the hydrogen completely so that the size of the molecule would be not much larger than the size of a single oxygen atom.
4. Deuterium has about the same atomic volume as hydrogen (where'd you get 40% less?) but the atomic mass is naturally about doubled (1 proton +1 neutron vs 1 proton - and almost all the mass is in the nucleus), thus the density of D2 is twice that of H2.
Actually I was wrong - by that reasoning the volume should be smaller almost by a factor of 3 (2^1.5), however I would expect electrostatic repulsion to kick in before this factor is reached.
5. The density difference between D2 and H2 is of no practical value for fuel cells. It'd be worse to use D2 since it's heavier and the increased density comes from the nuclei, not from an increased number of atoms per volume. And you're not getting energy out of the nucleus but out of the rearrangement of chemical (electronic) bonds. At least until we start talking about nuclear-powered cars. Then count me in!
That was just an example. I thought by density we meant energy content per volume, not per unit of mass ? Since for a car mass is of lesser concern than volume. As for nuclear powered cars - me too :)
This is actually a very interesting question. Let's see if I can get this right:
Each atom has positively charged nucleus and a bunch of electrons, so the whole thing is neutral. The more electrons we have the bigger the attraction force. Thus, while the diameter of the atom grows with element number it does so only slowly and one can consider atom size to be roughly constant - especially for elements like H, O, B.
What determines the volume of the liquid is then the size of the molecules composing it - and a molecule like H2O has some parts of the electron shells overlapping.
However, in case of pure hydrogen it is so light that besides pure electrostatic repulsion one also has uncertainty principle - the mass of H2 is so small that it cannot be within a very small volume or it would have to possess a large momentum (and thus be very hot).
If I am right it would mean that deuterium would have 40% less volume for the same number of atoms as hydrogen - but I don't have a ready reference - crosscheck anyone ?
I always wondered why everyone assumed that going to a different planet will do the trick.
Being in space and using raw material of asteroids and comets (not to mention free furnace in the form of the Sun) promises to be much more efficient.
Ok, someone has got to explain to me what is funny about it... Or were there several replies all asking for the resume ?
Are you close to Boston ? Know bash or Tcl ? Do you have your resume somewhere online ? Thx !
It was nice, but I did not find the AI challenging enough. Some silly moves were too easy to spot and exploit over and over again.
In Civ, playing on a deity level is always chancy, requires attention, and I often cannot win if I am not on an island.
Civilization is probably the only game with both graphics and moderately sophisticated AI and having random maps that actually matter.
In most other graphical games either AI is non-existent, or trained on a small set of maps - often both.
Why there is no fantasy-themed game with sophistication of Civ is beyond me..
One and half hour when on battery.
That's the ironic part - switching over to a spare is faster than even a 1-hour response plan (if they sell such). And most of the medium to high end hardware that assures reliability (like hardware RAID cards) can be purchased without going through one of the big vendors.
I've been using PCs for everyone recently and they are pretty good though not the least expensive out there. The good part is that they preinstall Linux and make sure it works - some of the more expensive hardware I never had any experience with.
Also, as far as support goes, if the price savings are big enough (say 50%) one can just ignore hardware breaking down and replace it with a new box. Works well for general purpose compute needs.
And even lower if instead of buying from IBM one uses a local computer shop. Last time I looked at IBM's website one could buy two generic boxes for the price of one that IBM sells, especially if one wants to max out the RAM.
So you deny being an optimist ? :)
Not that journalists haven't been known to manipulate a few words here and then, but these clarifications just do not sound as a solid rebuttal at all - more like politics. They dispute the attribution of the words, rather then their content and, at that, take care not to explicitly say "I really think the reverse of what was printed in the article".
2 people out of how many billions ? You, my friend, are an optimist.
I know some other nice people, but my point still stands - a handful of diamonds scattered on the beach will not make it sparkle - especially after several tides passed through.
Now, if you had reason to believe that humans improve as a species and in 100 years we can expect everyone to be at least that nice, that would be a completely different discussion..
I actually misspelled, the book name is "pocket sql" or something like that, it describes sql syntax specific to sql server, oracle, db2 and mysql.
As for "low end" this is very relative. I am crunching through .7 TB of data sitting in MySQL right now and it is quite efficient. In particular, if one were to construct a metric like database_ops/$$ then it is not exactly obvious which DB will come out on top - not needing to count the licenses one has make for much easier deployment on clusters.
An free software product with well-understood design and performance and unrestricted scalability is often the only answer to a high-end problem.
O'Reilly pocket mysql. Or just read MYSQL docs.
You mean a cdrom ?
And besides, yes, name is nice, but could they instead have a short description of major design choices they are considering ? Or why a particular characteristics (mass, size, shape) were settled on ?
Come on, "science" article that talks about a name choice - get a grip !
No need to rub it in. He is looking for a new PDA.
Hopefully this would be similar to what happened to Helium.
Unfortunately, it does not work like this anymore - if it ever did.
The world is global and business is getting increasingly efficient at monopolizing entire markets, let alone niche products.
This is a natural thing - as the technology progresses the lifetimes of the individual products are shrinking. It is not efficient to build a lasting business on new products which are not likely to be in use in 10 years. Rather, a common strategy is to achieve an established position in the market as fast as possible and then exchange it for capital - usually through sale of the company. The acquirer often specializes in maximizing short-term profit from established market.
A company with a DRM locked-in computer will attract more capital in the market due to perceived solidity of their "intellectual" property - as opposed to the company that plays by the rules and sells unlocked computers. This extra capital can be used in a number of ways to squeeze out competitors - for example by launching frivolous lawsuits.
In other words, if you give a freebee (in the form of not enforcing spirit of GPL) to those that tend to abuse it one should not be surprised that they win.
I am glad you see my point.
What GPL does is break down the barriers separating passive users that push on buttons from active contributors to free software community. A person pushing buttons and thinking "I wish this worked slightly differently" can decide to open up the source file, make a change and try it out. The free availability of development tools and source code have seen to that.
What lock-in does is remove that choice from the user - and why exactly should the open source developer be interested in that ? They get no compensation from the distributor, they cannot sell support because the software does not allow patches to be applied and they don't get contributions back from users of locked-in platform.
Lock-in via DRM software is a way for an unscrupulous person to put a tax on the network effect that have lead to the success of free software.
This has nothing to do with not letting someone else make a profit and has all to do with not letting someone else lock you into some restricted platform and extort all they can get away with.
In response to grandparent, GPLv3 will become very relevant when you see some scum mass produce a $150 computer with GNU/Linux that is cryptographically locked and then sell $10 "extension" cartridges with popular free software, in the same way that Sony locks its gaming consoles.
GPL is about freedom to modify and share code and DRM implementations take away your ability to modify your software.
Not Mars either.
To cache data from 160TB server. What kind of question is that ?