I practice Aikido 4 times a week. I use it to blow off steam and cope with the rest of the world. Am I addicted to Aikido? I don't know, but it does make me feel better and I get antsy and a bit off when I miss practice.
Also, some doctors are talking about information addiction where some people get addicted to being able to reload the news page and get instant everything. I don't know if their have been any clinical studies yet.
The addictive tendancies may also be related to the idea of amount of work put in versus the apparent reward that you receive. You don't have to work to hard (click to victory) but you get all these rewards that make you feel better.
Part of the problem is that the people writing these books are working full time and writing in their free time. So they can't dedicate 8 hours a day to writing. They dedicate 5-10 hours a week on writing. So it takes several years to write a book on the subject. Most of the books I have seen are written by college professors, so they can't just take six months off to write a book. They still have to teach, conduct and publich their research and oversee their grad students. They can't just drop everything because they want to write a book. Also the authors have to stay in touch with the subject matter that they are working on (ie you can't go hide out while writing or you lose touch). Otherwise, their peers and editors will shoot the book down when it gets to editing.
If I publisher look at two different books, Book A and Book B. Both have the same number of pages and printing requirements. Both will have the same set up time for equipment and presses. Everything is the same except that Book A will sell 100,000 copies its first month of sales and Book B will sell 1,000. Both books have to recover the costs associated with the set up and down time that is needed before you start pressing books. Smaller books cost more per page: If I (as a publisher) am going to be printing a low volume, small book- I may have idle to some of the presses in that line while this book is printed. I still have to pay the people who operate the idled machines (Check your union contract before you start laying people off), heat the building, have air conditioning etc.
As an example: If the overhead cost at a publishing house is $10,000 to be ready to start printing, Book A will have an added cost of 10 cents. Book B will have an added cost of 10 dollars. This is for everytime the book is reprinted. Publishers try not to sell books at a loss, and neither do book stores.
So when you ask yourself how many tech books sold this month- You stated in the parent: Why? These books are standards and needed by everyone. They should be able to capitalize off the popularity by lowering the price. Surely it doesn't take $120 to make Mitchell's Machine Learning--it's such a tiny book!. Your correct statement would be: These are books needed by all Computer Science Majors/programmers. After stating it that way you cut down on a lot of the potential market. The number of people who graduated from college in the US is 23.8%. From there you can weed out the anyone who didn't take a programming class (Art, Business, Literature, History, Medicine, Fashion Design, Dance, Social Policy, Accounting, Politics, etc). After that weed out the ones who took one or two programming courses because it was required for their major (Mechanical Engineering, Civil Engineering, Architecture, Areonautical Engineering, Physics, Bio-Engineering, Structural Engineering, etc). From there, there is maybe one in one thousand people who are potential customers for that book. With a US population of 295 Million people, that would give you 295,000 potental customers. Remove anyone who already has a copy of the book, buys one used, or has a similar book and doesn't feel like buying another AI book you chop the market down quite sharply. I haven't purchased many tech books since I graduated from college (a couple of references for the FE/EIT). Those books have still served me quite well. So back to the point above: Book A sells 100,000 copies in the first month, with continuing sales for the next couple of years so a large initial print run is justified. Book B may sell 5,000 per semester. Which is going to cost more to print, store and sell?
An interesting reference on selling books from Publishers Marketing Association. It may answer some of your questions. Their estimate is that you reach between 0.01% and 10% of your potential market with a given book.
Side note:
Once you see books being sold for $5-$10 in the bargain bin, those books aren't being sold at cost, they are being sold below cost to get them out the door because they are taking up sales space that other (money making) books could be using.
What it sound like to me is that some other product got yanked out of the presentation at the last minute and that was put in its place. Steve Jobs is known to be a stickler for having things correct for those presentations. Maybe something didn't work right, got yanked and replaced with a second stringer that was on stand by (it was going to be introduced and sold anyway, it just wasn't going to get the dog and pony show to go with it).
IBM only settles when the suit is not over part of their primary business strategy. They look at it and say: Is this suit going to endanger our core business at any time in the future? If yes-don't settle. If No-Get out of here kid, you bother me (take this settlement and leave).
Look at their lawsuit with the US Gov. That lasted decades. If their was going to be a settlement: it would have been years ago.
IBM is playing this lawsuit by the book and very cleanly. They are out to make an example out of SCO for trying to smack IBM up with a nuisance suit that threatened their core business. To to do that they are making sure that their side is cleaner then the preacher's sheets.
Recently it came out the SCO had subpeaned IBM about Groklaw. Quoting from Groklaw:
...We learn from this filing that SCO asked IBM back in August for all documents "concerning the financing, funding, sponsorship, or promotion of Groklaw." It's found in Exhibit 18. IBM replied in Exhibit 19, beginning on page 11:
In addition to the foregoing general objections, IBM objects specifically to this Request on the grounds that it is vague, ambiguous, overbroad, unduly burdensome, and seeks information that is irrelevant and not reasonably calculated to lead to the discovery of admissable evidence. IBM also objects to this Request on the grounds that the content of the Groklaw website, a non-IBM, publicly accessible website, is as accessible to SCO as it is to IBM. Subject to, as limited by, and without waiving the foregoing general and specific objections, IBM states that it does not finance, fund, sponsor, or promote Groklaw; IBM does not have any agreements or arrangements with Groklaw or Pamela Jones, and IBM does not necessarily agree or disagree with the content of any of the material published on Groklaw.
Also, Judge Kimble is also making sure that he is dotting all of his i's and crossing his t's so make sure there are no problems when this case is appealled by SCO. The judge has given SCO several warnings that the case is not looking favorable toward them.
The most notable warning to SCO was when the judge denied IBMs request for Partial Summary Judgements (PSJ). The denied them because discovery was not complete and wanted to make sure that he had the whole picture. In the denial he stated that he was surprised at the lack of evidence that SCO had provided (even to fight off a PSJ).
If you get hit in a current body armor vest (SWAT, police, etc, military armor is another ball of wax), odds are on that you will get a couple of broken ribs when your vest soaks up the bullet. But then you have a couple of broken ribs and can heal up. The other option is not as fun.
I lbew my math a little bit on the time line with the spread sheet but the underlying idea is still there.
Reaction time in the material
on
Flexible Body Armor
·
· Score: 2, Interesting
For body armor purpses:
The material's reaction time is probably related to how fast the shock-wave of the hit travels through the material. For the sake of arguement: The of the impact shockwave travels through the suit at the same speed sounds travels in water (sound is a shockwave). So it travels roughly 1482 m/s. So the shockwave would take roughly 0.0001 seconds to travel across my entire chest. Modern bullets can travel roughly the same speeds. In that same 0.0001 seconds a bullet would be several inches behind me.
So here comes the messy part: Can this kind of stuff protect a person from gunfire?
So a bullet hits a person wearing this stuff. In the first 10^-6 of a second the bullet travels.0004 (four ten-thousands) of an inch into me. In the same time the armor hardens in an circle with a radius of.0004in (For the sake of arguement a very thin bullet). In the next millionth of a second the bullet travels an additional.0004 of an inch into the target. The armor now also has a circle of.0008in in diameter. The affected area starts to grow rather quickly.
Time Depth/Shockwave Area Affected
0.000050: 0.2000: 0.1256637061
0.000100: 0.4000: 0.5026548246
0.000150: 0.6000: 1.1309733553
0.000200: 0.8000: 2.0106192983 0.000250: 1.0000: 3.1415926536
0.000300: 1.2000: 4.5238934212
0.000350: 1.4000: 6.1575216010
0.000400: 1.6000: 8.0424771932
0.000450: 1.8000: 10.1787601976
In the time it takes the bullet to travel 1 inch into the body enough of the armor has hardened to cover 3 square inches of the target's body. Now the bullet has to deform or move that much more material in order to continue its trip in. Most likely the person could end up with a weird dent in their body where the bullet hit. This is of course dependant upon when the material fails and stops giving protection and how fast the shockwave travels through the material.
Considering that though: I'd rather have a dent in my body then a hole.
Currently the ski suits are used to protect against impacts against relatively flexible things at speeds above sixty miles per hour. So for the athletes to approve of it, it has to work pretty quickly and revert pretty quickly. You are in contact with gates for hundredths of a second and if the armor/fluid reacts fast enough for the athletes to notice and approve, you know the army is going to buy a suit and shoot at it to see what the results are going to be. Imagine the next round of (Disposable) ceramic armor plates that is sent to the troops in Iraq is coated in that stuff and it improves survivability.
Hell, coat the inside of the flak vests in the stuff and have it sent to the firing range for testing. The army always loves things that do the following: improved force protection with less weight. While the army is a giant monolithic beuracracy it does actually get things done once in a while.
It is called a Methane Digester. It takes farm animal (cows, chickens, hogs) manure and stores it in tanks.
What happens in the tank:
The existing bacteria in it eats the remaining food in the manure and produces methane and carbon dioxide. The remaining fluid is a mixture of nitrates and lignin (non reactive solids). The water can be spread directly on the fields as a fertelizer. The lignin can be spread on the fields as well or used on the farm as a bedding or filler. Since the bacteria have eaten all the food by before the water is drawn off it dies before being spread in the fields and is more environmentally friendly all the way around.
Here is a good short study on the matter: Minnesota Dept of Agriculture
The study shown there used a 135kW generator. Currently they are beginning research to determine if fuel cells can be used. It looks neat.
Part of the issue is when he refers to the Ghawar field in Saudi Arabia. It produces roughly 6% of the world's oil production (5 million barrels/day). The Burgan Field in Kuwait recently had to scale back its production because it couldn't sustain a pump rate over 1.7 million barrels per day (That's about 2% of the world production). When the two biggest producing oils fields in the World have their production rate capped: you either have to look else where for additional oil or you have to start using less. In the mean time you end up with more people who want oil then can be supplied. Then who ever can pay for it will get it.
I was in a brick and mortar Apple store during the cristmas rush. Alot of people were just coming in for iPods. So anyone who wanted an ipod went to the ipod kisok in the apple store and were taken care of there. I saw two Customer Reps at the time and they were working through customers very fast. The line was 6-8 people deep but I would swear the wait was under ten minutes for any given people.
Normally the Appple store in my area is fun to browse, wander thorugh and try things out. It was designed so people can browse without feeling crowded or harried. Converting one of the sidewall sections into a dedicated sales point for a high volume product makes perfect sense to me.
Because of the ipod specific section, the rest of the store retained its charm and usefulness, i.e. there wasn't a swarm of people all over the store asking "Where do we get ipods" interfering with people who wanted to buy other things (computers, cameras, software, etc etc).
Thought of another way: It was a clever form of crowd control to keep the store manageable.
Try the Scientific American article on the DARPA challenge:
Innovations from a Robot Rally
It covers all the teams a bit and talks about some of the innovations that were used by the competing teams. It is a little light but worth a minute or your time.
Most other systems that you could encounter that use server racks also assume a raised floor system (ie process control equipment). If you are working with process control: all of one type of wiring cabinet is kept together. The outside-process-to-inside controller cabinet is in one area, the inside-to-decision system is seperate, emergency-shutdown is another. Usually for systems like process control there are several different systems that have to be wired seperately.
And when you lay your system out for that you want to keep all the same type of equipment together because otherwise it becomes more then a pain in the ass to work on later.
For other equipment: the wire has to go to the target. If that room serves the entire floor (or building) then all of the wires will end up in that room at some point. I have usually observed that design of those kinds of rooms happen in this way: lay out the cabinets first, insure fit of the cabinets, check to make sure it is not going to conflict with the architect's design and the weight limit is acceptable to the building. Confirm location of specialized HVAC entry points. Done. Wiring to be fitted in field. but then electricians always install last, they are the most flexible of the trades for fitting. The install order is this: Ductwork, pipes, wires. Electricians always get stuck with fitting around everyone elses patches of the construction process.
Heating Ventilation and Air Conditioning (HVAC) design is based upon how air moves through a given pipe or duct.
When you are designing for a space (such as a room) you design for the shortest amount of ductwork for the greatest amount of distribution. Look up in the ceiling of an office complex sometime and count the number of supply and return diffusers that work to keep your air in reasonable shape. All of the ducts that supply this air are smooth, straight and designed for a minimal amount of losses.
All air flow is predicated on two imporant points within a given pipe (splits and branching with in the duct work is not covered here): pressure loss within the pipe and how much power you have to move the air. The higher the pressure losses, the more power you need to move the same amount of air. Every corner, turn, rough pipe, longer pipe all contribute to the amount of power needed to push the air through at the rate you need.
Where am I going with all of this? Well under floor/raised floor systems do not have alot of space under them and it is assumed that the entire space under it is flexible and can be used (ie no impediments or blockages). Ductwork is immobile and does not appreciate being banged around. Most big servers need immense amounts of cooling. A 10"x10" duct is good for roughly 200 CFM of air. That much air is good for 2-3 people (this is rough, since I do not have my HVAC cookbook in front of me.. yes that is what it is called). Servers need large volumes of air and if that ductwork is put under the floor, pray you don't need any cables in that area of the room.
Before you ask: Well why don't we just pump the air into the space under the floor and it will get there? Air is like water, it leaves through the easiest method possible. Place a glass on the table and pour water on the table and see if any of the water ends up in the glass. Good chance it ends up spread out on the floor where it was easiest to leak out. Unless air is specifically ducted to exatcly where you want it, it will go anywhere it can (always to the easiest exit).
Ductwork is a very space consuming item. Main trunks for 2 and three story buildings can be on the order of four to five feet wide and three to four feet high. A server room by itself can require the same amount of cooling as the rest of the floor it is on. (ignoring wet bulb/dry bulb issues, humidity generation and filtering, we are just talking about number of BTUs generated). A good size server room could easily require a seperate trunk line and return to prevent the spreading of heated air throughout the building (some places do actually duct the warm air into the rest of the building during the winter). Allowing this air to return into the common plenum return will place an additional load on the rest of the buildings AC system. Place the server on a seperate HVAC system to prevent overloading the rest of the building's AC system (which is designed on a per square foot basis assuming for a given number of people/computers/lights per square foot if the floor plan does not include a desk plan layout).
Generally there are two sources of nitrogen in a gasoline engine. From the air ( air is 78% N2 and 21% O2 with the rest being a variety of other gases) and from the hydrocarbon (ie gasoline). Gasoline has all sorts of impurites in it, nitrogen amongst them. Usually breaking down the existing Nitrogen in the air is not considered a problem because preignition and engine failure are more of a concern (I'm not saying it doesn't happen). Usually NOx comes from the existing nitrogen that is part of the gasoline (or the fillers that are part of the gasoline). At this point trying to reduce the amount of NOx generated has to do with reducing the amount of nitrogen in the fuel supply and most suppliers don't want to have to deal with that because of the expense.
100% combustion does not give emission free power. It means that you have consumed all of the available fuel. There are always combustion by-products. With gasoline/methane etc, the main byproducts are CO2 and water. Then you have all the nasty other byporducts that are measured in ppm: NOx, partially burnt hydrocarbons, etc.
This assumes you are staying in the gasoline/combustion discussion.
If you are talking fission then there is the possibility of the fuel being 100% consumed in the process. Look up you local nuclear power plant or atomic bomb for more details.
Slashdot Mirror
I practice Aikido 4 times a week. I use it to blow off steam and cope with the rest of the world. Am I addicted to Aikido? I don't know, but it does make me feel better and I get antsy and a bit off when I miss practice. Also, some doctors are talking about information addiction where some people get addicted to being able to reload the news page and get instant everything. I don't know if their have been any clinical studies yet. The addictive tendancies may also be related to the idea of amount of work put in versus the apparent reward that you receive. You don't have to work to hard (click to victory) but you get all these rewards that make you feel better.
Like I said: Check your union contract first. Which is more economical: paying the people to run the idle machinery or having a plant wide strike?
Part of the problem is that the people writing these books are working full time and writing in their free time. So they can't dedicate 8 hours a day to writing. They dedicate 5-10 hours a week on writing. So it takes several years to write a book on the subject. Most of the books I have seen are written by college professors, so they can't just take six months off to write a book. They still have to teach, conduct and publich their research and oversee their grad students. They can't just drop everything because they want to write a book. Also the authors have to stay in touch with the subject matter that they are working on (ie you can't go hide out while writing or you lose touch). Otherwise, their peers and editors will shoot the book down when it gets to editing.
You still have to pay someone for the formating and layout. And if volume is low, then you have to make the money up in price.
As an example: If the overhead cost at a publishing house is $10,000 to be ready to start printing, Book A will have an added cost of 10 cents. Book B will have an added cost of 10 dollars. This is for everytime the book is reprinted. Publishers try not to sell books at a loss, and neither do book stores.
So when you ask yourself how many tech books sold this month- You stated in the parent: Why? These books are standards and needed by everyone. They should be able to capitalize off the popularity by lowering the price. Surely it doesn't take $120 to make Mitchell's Machine Learning--it's such a tiny book!. Your correct statement would be: These are books needed by all Computer Science Majors/programmers. After stating it that way you cut down on a lot of the potential market. The number of people who graduated from college in the US is 23.8%. From there you can weed out the anyone who didn't take a programming class (Art, Business, Literature, History, Medicine, Fashion Design, Dance, Social Policy, Accounting, Politics, etc). After that weed out the ones who took one or two programming courses because it was required for their major (Mechanical Engineering, Civil Engineering, Architecture, Areonautical Engineering, Physics, Bio-Engineering, Structural Engineering, etc). From there, there is maybe one in one thousand people who are potential customers for that book. With a US population of 295 Million people, that would give you 295,000 potental customers. Remove anyone who already has a copy of the book, buys one used, or has a similar book and doesn't feel like buying another AI book you chop the market down quite sharply. I haven't purchased many tech books since I graduated from college (a couple of references for the FE/EIT). Those books have still served me quite well. So back to the point above: Book A sells 100,000 copies in the first month, with continuing sales for the next couple of years so a large initial print run is justified. Book B may sell 5,000 per semester. Which is going to cost more to print, store and sell?
An interesting reference on selling books from Publishers Marketing Association. It may answer some of your questions. Their estimate is that you reach between 0.01% and 10% of your potential market with a given book.
Side note:
Once you see books being sold for $5-$10 in the bargain bin, those books aren't being sold at cost, they are being sold below cost to get them out the door because they are taking up sales space that other (money making) books could be using.
When you dragged him away, did your hole cutter use Metric or English?
Where's my Battle Mech? I want my 100 tons of walking destruction!
What it sound like to me is that some other product got yanked out of the presentation at the last minute and that was put in its place. Steve Jobs is known to be a stickler for having things correct for those presentations. Maybe something didn't work right, got yanked and replaced with a second stringer that was on stand by (it was going to be introduced and sold anyway, it just wasn't going to get the dog and pony show to go with it).
IBM only settles when the suit is not over part of their primary business strategy. They look at it and say: Is this suit going to endanger our core business at any time in the future? If yes-don't settle. If No-Get out of here kid, you bother me (take this settlement and leave).
Look at their lawsuit with the US Gov. That lasted decades. If their was going to be a settlement: it would have been years ago.
IBM is playing this lawsuit by the book and very cleanly. They are out to make an example out of SCO for trying to smack IBM up with a nuisance suit that threatened their core business. To to do that they are making sure that their side is cleaner then the preacher's sheets.
End Quotation
I think that speaks for itself.
Also, Judge Kimble is also making sure that he is dotting all of his i's and crossing his t's so make sure there are no problems when this case is appealled by SCO. The judge has given SCO several warnings that the case is not looking favorable toward them.
The most notable warning to SCO was when the judge denied IBMs request for Partial Summary Judgements (PSJ). The denied them because discovery was not complete and wanted to make sure that he had the whole picture. In the denial he stated that he was surprised at the lack of evidence that SCO had provided (even to fight off a PSJ).
If you get hit in a current body armor vest (SWAT, police, etc, military armor is another ball of wax), odds are on that you will get a couple of broken ribs when your vest soaks up the bullet. But then you have a couple of broken ribs and can heal up. The other option is not as fun.
I lbew my math a little bit on the time line with the spread sheet but the underlying idea is still there.
For body armor purpses: .0004 (four ten-thousands) of an inch into me. In the same time the armor hardens in an circle with a radius of .0004in (For the sake of arguement a very thin bullet). In the next millionth of a second the bullet travels an additional .0004 of an inch into the target. The armor now also has a circle of .0008in in diameter. The affected area starts to grow rather quickly.
The material's reaction time is probably related to how fast the shock-wave of the hit travels through the material. For the sake of arguement: The of the impact shockwave travels through the suit at the same speed sounds travels in water (sound is a shockwave). So it travels roughly 1482 m/s. So the shockwave would take roughly 0.0001 seconds to travel across my entire chest. Modern bullets can travel roughly the same speeds. In that same 0.0001 seconds a bullet would be several inches behind me.
So here comes the messy part: Can this kind of stuff protect a person from gunfire?
So a bullet hits a person wearing this stuff. In the first 10^-6 of a second the bullet travels
Time Depth/Shockwave Area Affected
0.000050: 0.2000: 0.1256637061
0.000100: 0.4000: 0.5026548246
0.000150: 0.6000: 1.1309733553
0.000200: 0.8000: 2.0106192983
0.000250: 1.0000: 3.1415926536
0.000300: 1.2000: 4.5238934212
0.000350: 1.4000: 6.1575216010
0.000400: 1.6000: 8.0424771932
0.000450: 1.8000: 10.1787601976
In the time it takes the bullet to travel 1 inch into the body enough of the armor has hardened to cover 3 square inches of the target's body. Now the bullet has to deform or move that much more material in order to continue its trip in. Most likely the person could end up with a weird dent in their body where the bullet hit. This is of course dependant upon when the material fails and stops giving protection and how fast the shockwave travels through the material.
Considering that though: I'd rather have a dent in my body then a hole.
Currently the ski suits are used to protect against impacts against relatively flexible things at speeds above sixty miles per hour. So for the athletes to approve of it, it has to work pretty quickly and revert pretty quickly. You are in contact with gates for hundredths of a second and if the armor/fluid reacts fast enough for the athletes to notice and approve, you know the army is going to buy a suit and shoot at it to see what the results are going to be. Imagine the next round of (Disposable) ceramic armor plates that is sent to the troops in Iraq is coated in that stuff and it improves survivability.
Hell, coat the inside of the flak vests in the stuff and have it sent to the firing range for testing. The army always loves things that do the following: improved force protection with less weight. While the army is a giant monolithic beuracracy it does actually get things done once in a while.
It is called a Methane Digester. It takes farm animal (cows, chickens, hogs) manure and stores it in tanks.
What happens in the tank:
The existing bacteria in it eats the remaining food in the manure and produces methane and carbon dioxide. The remaining fluid is a mixture of nitrates and lignin (non reactive solids). The water can be spread directly on the fields as a fertelizer. The lignin can be spread on the fields as well or used on the farm as a bedding or filler. Since the bacteria have eaten all the food by before the water is drawn off it dies before being spread in the fields and is more environmentally friendly all the way around. Here is a good short study on the matter: Minnesota Dept of Agriculture
The study shown there used a 135kW generator. Currently they are beginning research to determine if fuel cells can be used. It looks neat.
Part of the issue is when he refers to the Ghawar field in Saudi Arabia. It produces roughly 6% of the world's oil production (5 million barrels/day). The Burgan Field in Kuwait recently had to scale back its production because it couldn't sustain a pump rate over 1.7 million barrels per day (That's about 2% of the world production). When the two biggest producing oils fields in the World have their production rate capped: you either have to look else where for additional oil or you have to start using less. In the mean time you end up with more people who want oil then can be supplied. Then who ever can pay for it will get it.
A derailer is used on a multi-gear/multi-speed bicycle on the rear wheel. It is attached to the frame and moves the chain to the different gears when the rider twists the gear level on the handle bars.f f=1&safe=off&client=firefox-a&rls=org.mozilla:en-U S:official&q=derailleur&spell=1&sa=N&tab=wi
Try:
http://images.google.com/images?hl=en&hs=WBu&c2co
or
http://en.wikipedia.org/wiki/Derailleur
I was in a brick and mortar Apple store during the cristmas rush. Alot of people were just coming in for iPods. So anyone who wanted an ipod went to the ipod kisok in the apple store and were taken care of there. I saw two Customer Reps at the time and they were working through customers very fast. The line was 6-8 people deep but I would swear the wait was under ten minutes for any given people.
Normally the Appple store in my area is fun to browse, wander thorugh and try things out. It was designed so people can browse without feeling crowded or harried. Converting one of the sidewall sections into a dedicated sales point for a high volume product makes perfect sense to me.
Because of the ipod specific section, the rest of the store retained its charm and usefulness, i.e. there wasn't a swarm of people all over the store asking "Where do we get ipods" interfering with people who wanted to buy other things (computers, cameras, software, etc etc).
Thought of another way: It was a clever form of crowd control to keep the store manageable.
Try the Scientific American article on the DARPA challenge: Innovations from a Robot Rally
It covers all the teams a bit and talks about some of the innovations that were used by the competing teams. It is a little light but worth a minute or your time.
In some versions of the story. The goblin doesn't survive where the troll regenerates enough to go chest burster on the goblin.
Well over at Groklaw they were a considered contest to name the 2.7 kernel after SCO/IBM lawsuit. The 2.7 wouldn't have anything else but the name.
Most other systems that you could encounter that use server racks also assume a raised floor system (ie process control equipment). If you are working with process control: all of one type of wiring cabinet is kept together. The outside-process-to-inside controller cabinet is in one area, the inside-to-decision system is seperate, emergency-shutdown is another. Usually for systems like process control there are several different systems that have to be wired seperately. And when you lay your system out for that you want to keep all the same type of equipment together because otherwise it becomes more then a pain in the ass to work on later. For other equipment: the wire has to go to the target. If that room serves the entire floor (or building) then all of the wires will end up in that room at some point. I have usually observed that design of those kinds of rooms happen in this way: lay out the cabinets first, insure fit of the cabinets, check to make sure it is not going to conflict with the architect's design and the weight limit is acceptable to the building. Confirm location of specialized HVAC entry points. Done. Wiring to be fitted in field. but then electricians always install last, they are the most flexible of the trades for fitting. The install order is this: Ductwork, pipes, wires. Electricians always get stuck with fitting around everyone elses patches of the construction process.
When you are designing for a space (such as a room) you design for the shortest amount of ductwork for the greatest amount of distribution. Look up in the ceiling of an office complex sometime and count the number of supply and return diffusers that work to keep your air in reasonable shape. All of the ducts that supply this air are smooth, straight and designed for a minimal amount of losses.
All air flow is predicated on two imporant points within a given pipe (splits and branching with in the duct work is not covered here): pressure loss within the pipe and how much power you have to move the air. The higher the pressure losses, the more power you need to move the same amount of air. Every corner, turn, rough pipe, longer pipe all contribute to the amount of power needed to push the air through at the rate you need.
Where am I going with all of this? Well under floor/raised floor systems do not have alot of space under them and it is assumed that the entire space under it is flexible and can be used (ie no impediments or blockages). Ductwork is immobile and does not appreciate being banged around. Most big servers need immense amounts of cooling. A 10"x10" duct is good for roughly 200 CFM of air. That much air is good for 2-3 people (this is rough, since I do not have my HVAC cookbook in front of me.. yes that is what it is called). Servers need large volumes of air and if that ductwork is put under the floor, pray you don't need any cables in that area of the room. Before you ask: Well why don't we just pump the air into the space under the floor and it will get there? Air is like water, it leaves through the easiest method possible. Place a glass on the table and pour water on the table and see if any of the water ends up in the glass. Good chance it ends up spread out on the floor where it was easiest to leak out. Unless air is specifically ducted to exatcly where you want it, it will go anywhere it can (always to the easiest exit).
Ductwork is a very space consuming item. Main trunks for 2 and three story buildings can be on the order of four to five feet wide and three to four feet high. A server room by itself can require the same amount of cooling as the rest of the floor it is on. (ignoring wet bulb/dry bulb issues, humidity generation and filtering, we are just talking about number of BTUs generated). A good size server room could easily require a seperate trunk line and return to prevent the spreading of heated air throughout the building (some places do actually duct the warm air into the rest of the building during the winter). Allowing this air to return into the common plenum return will place an additional load on the rest of the buildings AC system. Place the server on a seperate HVAC system to prevent overloading the rest of the building's AC system (which is designed on a per square foot basis assuming for a given number of people/computers/lights per square foot if the floor plan does not include a desk plan layout).
Generally there are two sources of nitrogen in a gasoline engine. From the air ( air is 78% N2 and 21% O2 with the rest being a variety of other gases) and from the hydrocarbon (ie gasoline). Gasoline has all sorts of impurites in it, nitrogen amongst them. Usually breaking down the existing Nitrogen in the air is not considered a problem because preignition and engine failure are more of a concern (I'm not saying it doesn't happen). Usually NOx comes from the existing nitrogen that is part of the gasoline (or the fillers that are part of the gasoline). At this point trying to reduce the amount of NOx generated has to do with reducing the amount of nitrogen in the fuel supply and most suppliers don't want to have to deal with that because of the expense.
100% combustion does not give emission free power. It means that you have consumed all of the available fuel. There are always combustion by-products. With gasoline/methane etc, the main byproducts are CO2 and water. Then you have all the nasty other byporducts that are measured in ppm: NOx, partially burnt hydrocarbons, etc. This assumes you are staying in the gasoline/combustion discussion. If you are talking fission then there is the possibility of the fuel being 100% consumed in the process. Look up you local nuclear power plant or atomic bomb for more details.