I worked on a project with another guy for about 4 months. I asked him to write a short snippit of simple 'C' code, one that would print out a message.
He was hired to write 'C++' code, but it turned out that, even after 4 months on the project, he didn't even know how to write a program that would print
#1 problem with backups:
Nobody tests/attempts/documents a restore.
Yea. Because you need a similarly configured free machine that you're not afraid to trash the drive in case something goes wrong in the middle of the restore.
Would you like to hear a horror story?
I have to agree with poster roman_mir. You have to use common sense when normalizing your database. I worked on a project once that called for bringing up a display in under a second. It took 10 seconds to get a connection and query the database to get the the data for the screen. (Oracle was slow in those days.) Largly because the db designer lacked insight on how to setup the tables.
I believe that most vegetable oil is made from soybeans. Unlike corn, soybeans don't require nitrogen fertilizer (derived from fossil fuels) to
grow. In fact they produce it.
I still can't, with certainty, deny your claim that
it takes more energy to produce organic oil than is taken out by burning it. There is a certain amount of energy required to processing the soybeans to oil.
However, using waste oil from making french fries is still a good idea, as the oil would otherwise be thrown away.
There must be some merit to using biodiesel. A new
biodiesel plant just started operating in SW Minnesota in March.
Most of the debris that is in need of deorbiting is not radioactive. Like the article said, it's pieces of paint, bits of solid fuel, copper needles, etc.
The leak mentioned in the article was a coolant leak, not the main radioactive material. The coolant would get slightly radioactive over time, being in close proximity to the radioactive fuel. The main radioactive material was boosted into higher orbit.
The problem is that a scramjet trades a dense propellant (LOX) for more of a low density propellant (LH2).
Not true. LOX is an oxidizer. LH2 is a fuel.
Scramjets eliminate the need to carry the oxidizer. You would still need to carry the LH2
or other fuel in the rocket. Not only that but because you're also carrying the heavy oxygen, you need to carry MORE fuel. (and MORE Oxygen with which to burn it, (and MORE fuel...))
Furthermore you want to carry with the vehicle a fuel that has a high energy to weight ration ( like LH2).
You don't want something that is heavy (dense)with a low energy to weight ratio.
Re:Perfomance and economy
on
X-43A Hits Mach 7
·
· Score: 2, Informative
Mod parent up. This is correct. Orbital velocity is the velocity an object needs to maintain an orbit about a planet (or another object). This is a tangential velocity. Escape velocity is the velocity necessary for escaping the gravitational pull of the planet (or other object). Escape velocity is faster than orbital velocity. But like the parent poster says only a relatively small amount of thrust is needed to gain escape velocity.
Most of the energy in the fuel in a rocket is used to accelerate the remaining fuel in the rocket. Not having to carry along the oxidizer for the lower portion of the flight would save a lot of weight. And with less oxidizer you need less fuel as well.
I read once upon a time (probably in Popular Science ) that eventally that scientists would like to get spacecraft into orbit using a four stage system. (Hopefully economically)
First - Jet engine based craft takes off from runway and goes to supersonic speeds.
Second - Ramjet takes over ( speed must be supersonic for a ramjet to operate) and accelerates to about Mach 4 or 5.
Third - Scramjet takes over and builds speeds to some higer Mach number (10-20)?
Fourth - Rocket engines power vehicle to orbital velocity.
The idea being that since most of the engines use air from the atmosphere for combustion, that the amount (weight)of oxidizer that the craft needs to cary to get into orbit is drastically reduced. Hence the total amount of fuel and propellant needed to get into orbit is drastically reduced as well.
Yes. I too think they underestimated inflation during that time. My guess is that $100 in 1954
would be about $1200 today. So that $400 televison would be the equivalent of $4800.
Why exactly has it taken North America so long to change to a better format? I'd imagine the HDTV change will happen almost overnight, much like the DVD revolution,...
HDTV has been available in the US for several years now. Consumers aren't purchasing the receivers because of the high costs. The cost remains high because manufacturers can't yet reach economies of scale. So in order to start the ball rolling on the changeover to HDTV, the FCC says theat in 2006 all
receivers sold must be capable of receiving HDTV.
It's kind of like that old situation with red barn paint.
Interviewer (to hw store manager): Why are all the barns around here painted red?
Manager: Because red paint is cheaper than other colors.
Wow! The reliability of their machines must have really gone downhill since the latter 80's. I remember working on a system which had number of their computers. Several of the machines never went down during the 7 months of software development, ('uptime' command). The others were down only because they were taken down.
The article referenced didn't mention anything about hp shipping mahines with linux pre-installed, but a press release from Novell did. Only for corporate customers requesting it, however.
Netware has had its heyday. When customers found out they needed TCP/IP to internetwork, the days of a strictly local area network, as NetWare were numbered.
With their purchases of Ximian and SuSE last year, it was pretty clear that Novell managment saw the need to take their company in a new direction. Novell chooses to embrace the new world. SCO tries to fight against it.
Slashdot Mirror
(Or the commodore VIC?)
I wonder how many there are of them still stored up in attics somewhere.
I've been waiting for them to get bought up. Originally thought that HP may have bought them, but the merger of HP & Compaq proved me wrong.
'Hello World!'
I kid you NOT!
#1 problem with backups: Nobody tests/attempts/documents a restore. Yea. Because you need a similarly configured free machine that you're not afraid to trash the drive in case something goes wrong in the middle of the restore. Would you like to hear a horror story?
I have to agree with poster roman_mir. You have to use common sense when normalizing your database. I worked on a project once that called for bringing up a display in under a second. It took 10 seconds to get a connection and query the database to get the the data for the screen. (Oracle was slow in those days.) Largly because the db designer lacked insight on how to setup the tables.
That must have been bad. I know vi is quite usable at 2400 baud, if the connection is pretty good.
Or more likely, the steam engine they invented was
terribly inefficient and not practical.
I still can't, with certainty, deny your claim that it takes more energy to produce organic oil than is taken out by burning it. There is a certain amount of energy required to processing the soybeans to oil.
However, using waste oil from making french fries is still a good idea, as the oil would otherwise be thrown away.
There must be some merit to using biodiesel. A new biodiesel plant just started operating in SW Minnesota in March.
Most of the debris that is in need of deorbiting is not radioactive. Like the article said, it's pieces of paint, bits of solid fuel, copper needles, etc.
The leak mentioned in the article was a coolant leak, not the main radioactive material. The coolant would get slightly radioactive over time,
being in close proximity to the radioactive fuel. The main radioactive material was boosted into higher orbit.
I thought most communities don't allow ponies for pets these days. Couldn't imagine what all those apartment dwellers with ponies anyways.
Not true. LOX is an oxidizer. LH2 is a fuel. Scramjets eliminate the need to carry the oxidizer. You would still need to carry the LH2 or other fuel in the rocket. Not only that but because you're also carrying the heavy oxygen, you need to carry MORE fuel. (and MORE Oxygen with which to burn it, (and MORE fuel ...))
Furthermore you want to carry with the vehicle a fuel that has a high energy to weight ration ( like LH2). You don't want something that is heavy (dense)with a low energy to weight ratio.
Escape velocity is faster than orbital velocity. But like the parent poster says only a relatively small amount of thrust is needed to gain escape velocity.
Most of the energy in the fuel in a rocket is used to accelerate the remaining fuel in the rocket. Not having to carry along the oxidizer for the lower portion of the flight would save a lot of weight.
And with less oxidizer you need less fuel as well.
) that eventally that scientists would like to get spacecraft into orbit using a four stage system.
(Hopefully economically)
First - Jet engine based craft takes off from runway and goes to supersonic speeds.
Second - Ramjet takes over ( speed must be supersonic for a ramjet to operate) and accelerates to about Mach 4 or 5.
Third - Scramjet takes over and builds speeds to some higer Mach number (10-20)?
Fourth - Rocket engines power vehicle to orbital velocity.
The idea being that since most of the engines use air from the atmosphere for combustion, that the
amount (weight)of oxidizer that the craft needs to cary to get into orbit is drastically reduced. Hence the total amount of fuel and propellant needed to get into orbit is drastically reduced as well.
Yes. I too think they underestimated inflation during that time. My guess is that $100 in 1954 would be about $1200 today. So that $400 televison would be the equivalent of $4800.
Not quite, I read 'Commander Tacos'.
Except if you're flying directly to/from Mpls, Detroit, or the other of monopolist Northwest's Hubs.
I think they call that reality TV today.
I remember back when color TVs were first hitting the market. Old Walter Cronkite had a green face.
HDTV has been available in the US for several years now. Consumers aren't purchasing the receivers because of the high costs. The cost remains high because manufacturers can't yet reach economies of scale. So in order to start the ball rolling on the changeover to HDTV, the FCC says theat in 2006 all receivers sold must be capable of receiving HDTV.
It's kind of like that old situation with red barn paint. Interviewer (to hw store manager): Why are all the barns around here painted red?
Manager: Because red paint is cheaper than other colors.
Interviewer: Why is red paint cheaper?
Manager: Because we sell so much of it.
You seem to be one of the few ones here who knows what they're talking about
Wow! The reliability of their machines must have really gone downhill since the latter 80's. I remember working on a system which had number of their computers. Several of the machines never went down during the 7 months of software development, ('uptime' command). The others were down only because they were taken down.
The article referenced didn't mention anything about hp shipping mahines with linux pre-installed, but a press release from Novell did. Only for corporate customers requesting it, however.
... and it wrinkles easily.
Not to mention all the fossil fuels that were required to transport and turn the raw ore into usable metal.
Netware has had its heyday. When customers found out they needed TCP/IP to internetwork, the days of a strictly local area network, as NetWare were numbered.
With their purchases of Ximian and SuSE last year, it was pretty clear that Novell managment saw the need to take their company in a new direction. Novell chooses to embrace the new world. SCO tries to fight against it.