Sounds interesting. The idea basically is to get "one more cycle" by using ammonia as the working fluid. In a normal steam turbine, the enthalpy of the superheated steam goes down as we runs in through several cycles, with suitable reheats in between (so the graph looks kinda like a big step down, small step up, big step down etc...)
The final work done is some efficiency factor multiply by the difference in start and end enthalpy of the water. Now, usually, the "downstream steam" (i.e which is not useful/hot enough to do work anymore due to it's low pressure) is send up a cooling tower to be condensed back into water. The excess heat released by the condensation is lost into the atmosphere.
But in the scheme you detailed, the latent heat of condensation is used to superheat the mixed ammonia, which then goes through another turbine to get more work done. So in a sense, we get one extra "bang", which will improve the efficiencies of course.
The trick is that ammonia has a lower heat capacity than water, so it takes less to make superheat/high pressure ammonia vapour to do work. (Of course it does less work, but here we are utilizing the energy of which would have been lost anyway.)
And I was a Mech Engineer turned physics grad student. (Trading a nice paying job for the academia, where you get half the pay for twice the education.) And a geek of course.:)
Calling a truce in the power plant eff wars. There are probably ways to improve the efficiencies, but that will need some new breakthroughs (which we don't have). The current reheaters, flue-gas turbines, coolers, stuff we currently use has been pretty much maxed out. People are trying to muck around turbine-blade angles, playing around with convection in gas firing chambers, and stuff like that to get that extra 0.0001% efficiency nowadays, which shows you how refined the field is already. In a sense, the production of energy by chemical means is a pretty dead field (one hardly do PhDs in such fields anymore). The space rocketry industry is another good example how chemical energy production has reached "the point of diminishing returns". Basically, "burning" is an extremely inefficient way to get energy.
My prediction on the "breakthrough" needed : a theoretical understanding of how convection works.
(Wish somebody has told me this before I did 4 years worth of thermofluids. Now I have to reeducate myself in other more fertile fields..)
That is too simplistic. The heat engine depends on many other things. To use your example, the energy "lost" to the enviroment depends on whether you can keep the pressure or temperature of the, say, A, constant (isobaric and isothermal). The minimum loss to the environment is zero, which we call adiabatic. But this is not the whole story, because an ideal heat engine is a 4-step process (a bit like why your car has 4-strokes, a 2-stroke engine just combine the processes). The ideal theoretical "cycle" is the so-called Carnot cycle, which has a cycle of adiabatic-isothermal-adiabatic-isothermal processes.
The distinction is that efficiency is measure by the formula eff = WORK_DONE/HEAT_INPUT
and not eff != HEAT_TRANSFERED/HEAT_INPUT (which is what most people tend to think).
The 2nd law of thermodynamics states that you can only get a fraction of the heat transfered to do work. (Hmmm..this is one of the most simplistic statement of 2nd law I've ever made).
The max efficiency for the Carnot Cycle is given by the ratio (after solving some thermo eqns):
efficiency = (T1-T2)/T1 x 100%, of which T2 and T1 is the heat sink (B) and source (A) respectively, with the temparatures maintained by constant heating (your input energy) and exhaust of your medium.
For a typical temperature ratio, that's about 60%. Now, the ideal "adiabatic" cycle is impossible to achieve, one can only approximate (which is the function of all those reheaters in the power plant).
A standard 4-cycle plant runs at about 40%, which is pretty good. Cars run at 20-25%. This is EXCLUSIVE of _fuel burning efficiency_ (which is a different matter altogether : that's why my original post caused confusion because some readers are not aware of this distinction.) So for example, your car burns gasoline at 70% efficiency, but only convert this energy to mechanical energy (ie. Work) at 25%, your total car efficiency is then.7 x.25 = 17.5%.
We burn coal at 20% efficiency, because coal is such a "low quality" fuel source (lots of carbon). So if we use electric cars AND we have a coal-burning power plant as our source, we actually put more carbon into the air per mile than if we just burn plain old gas. That's my point.
OK, how the hell do I know all these crap? 4 years of college as a thermofluids major, and 1 year working with Shell in their gas production facilities. Damn it, I am sick and tired of engines and efficiencies!:)
Yes power plants will always be more efficient than cars. But note : (a) Transmission loss (getting power from PP to house, i.e. cable transmission loss, up/down conversion loss, connector patch losses, etc.) Power leaking during transmission is a big issue right now. (b) Charging loss (efficiency is not always good, that's why your battery is hot after charging) (c) Battery Conversion loss
My point is that electric cars is not the answer. It's to improve efficiencies, whether it's car eff, or power plant (unlikely), or just plain get rid of all the power leakage during transmission etc..
(Anyway, maximing aerodynamics, size, noise will improve efficiency, whatever the engine:) so it's worthwhile to pursue it).
Thermodynamics prevents us from getting anything more than 50% (the theoretical limit is about 60% depending on in/out temp ratios). AND That is assuming that you everything you put in is converted to heat, which is impossible. (i.e. there are two losses : thermodynamic 2nd law loss, which is theoretical limit due to entropy, and the "conversion loss" which states you can't get 100% all the stuff you put in into energy, which depends on the H to C ratio of your fuel.)
There is something called the 2nd law of thermodynamics. DEpending on what kind of heat cycle your generator uses, and the in/out temperature ratios. Even with all sorts of reheaters, coolers, flue-gas turbines, that's a number only God (if She is there) can achieve. And She has plenty of energy in Hell.
(a) Agree on the Solar Powered cars. Big batteries with solar-powered plants. (Imagine big "Gas" stations with solar panels.)
(b) Disagree on the efficiency of the power plants. Power plants efficiencies are almost maxed-out : it's a well developed science. And the efficiency max depends on the fuel you burn. The primary fuel, coal (because it's hard to put coal into anything smaller than a big power plant), has VERY low conversion efficiency. Even if you consider plants that burn gas or natural gas, the transmission loss can be as much as 40% (some cases more for long hauls). That will wipe out any advantage you get by tuning your system (which you probably can't).
People here seems to think that by putting stuff other than gas into their cars can (1) save the environment (2) save costs (3) look cool.
But this is all a myth, just something to make us feel good. The fact is that _cars burn fuel_ to move whatever the fuel is.
Electricity? Sure plug in your batteries into your house jack to charge em up! No Gas? WRONG! How the hell do the electricity gets to your jack anyway? It's coal, burnt at your nearest power station. That's more damaging to the enviro then gas.
Natural gas? That's still fuel. And it costs money and energy to either (a) compress them (b) process them. (I know, I work in a gas compression facility before.) That's fuel burned, kiddo. The savings to the environment is minimal.
(Now methanol is cool : it's made of sugarcane which is eminently renewable.)
The future is not about "what fuel you burn". It's about "how efficient is your engine". Natural gas has higher Hydrogen to Carbon ratio then gasoline, so they are more efficient. So is methanol. But NOT ELECTRICITY (unless it is solar powered. but solar powered cars are not going to be powerful enough since nature puts a limit on the efficiencies of GaAs solar cells at 25%.)
After the breakup, RSA (Russian Space Agency) decided to build a replacement for Baikanour in Svobodny. (http://www.fas.org/spp/guide/russia/facility/svob odny.htm)
Problem is that they ran out of cash so that place is right now half-completed.
The many posts about launching nearer to equator is better is true only for near equatorial launches (like the ISS which is in a SHuttle orbit of about 25deg inclination). For other polar launches (>67 deg inclination), the higher up you are in latitude, the better. Plesetk is then used for such launches if they can (much like the VDBAFB is used for such launches in the US.) The fuel savings can be tremendous (up to 10%.)
They have the biggest database of all US and foreign nationals.
They know your scores (remember that 450 on maths?), they know your address, they have your essays (that rant you wrote about the Pope?), they have everything to totally wreck your life...
Are you talking about absolute carrying capacity per Hz? That's 2 bits per Hz (there is some law that proves it but I can't recall what's the name), IF you just do "up-down" as bit 1 and bit 0. of course there is such schemes such as using a step scheme such as to squeeze 2^n bits per Hz (with n = # steps) out but they run into s/n problems.
You can go higher and higher frequencies if you wanna more juice. You pay for higher frequencies with more power to increase s/n of your signal. So as long as you have power, you can go as high as you want. The ceiling? I bet it's the melting temperature of your transmitter:)
OTOH, if your "bandwidth" means the fuzzy idea of "data carried", used by internet talking heads and news anchor people, then......
(a) magnotometer ok (b) you really need to land on the moon to be sure (c) you need good altitude and attitude control systems. (Doppler from earth don't work since the far side of the moon is not sighted)
Things to learn : (a) How do we get lunar magnetic fields? (b) Where and how much is water ice on the moon? (c) WHat is the Moon's gravitational field? (An important problem : we still haven't found what it's call "fix orbits" on the moon since we have not completely map the grav. field to high enough resolution)
These there problems would probably take a dedicated unmanned mission each, and (b) probably take a manned mission.
So my dear friend, the moon is a Very interesting place.
Just like the Russians launch Comrade Gagarin up to space for "Russian Pride", the Americans land Mr Armstrong ont he moon for "American Pride" etc.etc.etc..
If you wait to solve every problem on Earth before trying to do something else out of Earth, you'll be dead with overpopulation in a few decades.
A lot of credit should be properly accorded to the sequencers of course.
Granted, sequencing is so routine that it can be done by a bunch of monkeys (the quote's Jim Watson's, not mine so go yell at him). But that's only half the story : the hard part is getting putting together the system that allow the bunch of monkeys to sequence them. The computers, the algorithms, the $$$$, the political will, and the dedicated bunch of people who are doing admittedly tedious work (akin to copying out the Encyclopaedia Brittanica in Greek without knowing what Greek is.)
So, we should accord them the highest honours for pulling it off.
Gyroscopes are needed for attitude/pointing control, and has no relevant to chips i.e. you can't replace a gyro with a chip (a laser gyro is still a gyro).
Russians build things big out of historical/cultural reasons : their engineering is very robust and they do not often "go for the last mile" like western engineers do.
Russian efficient boosters are a Myth, their boosters are less efficient than most western boosters. The numbers they are throwing about are "fudged" in the sense that they add "back pressure thrust" to the numbers, while the standard western way of calculating efficiencies do not do that.
The cheapness of their launches is due to (a) their rockets are cheap because their labour/material/tax/overhead are cheap (b) they need to be cheap to compete with the protected western markets (eg. NASA forces NASA funded projects to go on American launchers.) (c) they have lots of "cheap ex-ICBMS" converted to LV and are selling them, all due to the START treaty (in fact they have a LV call "START-1", a converted SS-21)
That depends on your unit. In addition, you can build your own GPS receivers that bypass those. You can get download the specs from the net from the NRO site.
Another question is that will DELL/RH/IBM support it and is the cost of support factored into the preloaded box?
Finally, here's a multiple choice question :
Q: Why is IBM/DELL shipping boxes with Linux instead of Windoze?
(a) They want to piss off Bill Gates (nah nah nah nah, your's monopoly's gone!) (b) They listen to consumer demands (c) They play the "cool" card and hope to ride the linux-association stock craze (d) A Dell middle manager noticed that an unofficial desktop running linux was more stable (sic)
Slashdot Mirror
we can install our games directly into the Video Ram is the RAM is enough.
Sounds interesting. The idea basically is to get "one more cycle" by using ammonia as the working fluid. In a normal steam turbine, the enthalpy of the superheated steam goes down as we runs in through several cycles, with suitable reheats in between (so the graph looks kinda like a big step down, small step up, big step down etc...)
The final work done is some efficiency factor multiply by the difference in start and end enthalpy of the water. Now, usually, the "downstream steam" (i.e which is not useful/hot enough to do work anymore due to it's low pressure) is send up a cooling tower to be condensed back into water. The excess heat released by the condensation is lost into the atmosphere.
But in the scheme you detailed, the latent heat of condensation is used to superheat the mixed ammonia, which then goes through another turbine to get more work done. So in a sense, we get one extra "bang", which will improve the efficiencies of course.
The trick is that ammonia has a lower heat capacity than water, so it takes less to make superheat/high pressure ammonia vapour to do work. (Of course it does less work, but here we are utilizing the energy of which would have been lost anyway.)
Last Post! Have Fun!
And I was a Mech Engineer turned physics grad student. (Trading a nice paying job for the academia, where you get half the pay for twice the education.) And a geek of course. :)
Calling a truce in the power plant eff wars. There are probably ways to improve the efficiencies, but that will need some new breakthroughs (which we don't have). The current reheaters, flue-gas turbines, coolers, stuff we currently use has been pretty much maxed out. People are trying to muck around turbine-blade angles, playing around with convection in gas firing chambers, and stuff like that to get that extra 0.0001% efficiency nowadays, which shows you how refined the field is already. In a sense, the production of energy by chemical means is a pretty dead field (one hardly do PhDs in such fields anymore). The space rocketry industry is another good example how chemical energy production has reached "the point of diminishing returns". Basically, "burning" is an extremely inefficient way to get energy.
My prediction on the "breakthrough" needed : a theoretical understanding of how convection works.
(Wish somebody has told me this before I did 4 years worth of thermofluids. Now I have to reeducate myself in other more fertile fields..)
That is too simplistic. The heat engine depends on many other things. To use your example, the energy "lost" to the enviroment depends on whether you can keep the pressure or temperature of the, say, A, constant (isobaric and isothermal). The minimum loss to the environment is zero, which we call adiabatic. But this is not the whole story, because an ideal heat engine is a 4-step process (a bit like why your car has 4-strokes, a 2-stroke engine just combine the processes). The ideal theoretical "cycle" is the so-called Carnot cycle, which has a cycle of adiabatic-isothermal-adiabatic-isothermal processes.
.7 x .25 = 17.5%.
:)
The distinction is that efficiency is measure by the formula eff = WORK_DONE/HEAT_INPUT
and not eff != HEAT_TRANSFERED/HEAT_INPUT (which
is what most people tend to think).
The 2nd law of thermodynamics states that you can only get a fraction of the heat transfered to do work. (Hmmm..this is one of the most simplistic statement of 2nd law I've ever made).
The max efficiency for the Carnot Cycle is given by the ratio (after solving some thermo eqns):
efficiency = (T1-T2)/T1 x 100%, of which T2 and T1 is the heat sink (B) and source (A) respectively, with the temparatures maintained by constant heating (your input energy) and exhaust of your medium.
For a typical temperature ratio, that's about 60%. Now, the ideal "adiabatic" cycle is impossible to achieve, one can only approximate (which is the function of all those reheaters in the power plant).
A standard 4-cycle plant runs at about 40%, which is pretty good. Cars run at 20-25%. This is EXCLUSIVE of _fuel burning efficiency_ (which is a different matter altogether : that's why my original post caused confusion because some readers are not aware of this distinction.) So for example, your car burns gasoline at 70% efficiency, but only convert this energy to mechanical energy (ie. Work) at 25%, your total car efficiency is then
We burn coal at 20% efficiency, because coal is such a "low quality" fuel source (lots of carbon). So if we use electric cars AND we have a coal-burning power plant as our source, we actually put more carbon into the air per mile than if we just burn plain old gas. That's my point.
OK, how the hell do I know all these crap? 4 years of college as a thermofluids major, and 1 year working with Shell in their gas production facilities. Damn it, I am sick and tired of engines and efficiencies!
That's exactly the "militant linux" attitude that the article is warning against.
....and the FACT is ..".
"YOU should do THIS...YOU should'nt do that....Because I
Yes power plants will always be more efficient than cars. But note :
:) so it's worthwhile to pursue it).
(a) Transmission loss (getting power from PP to house, i.e. cable transmission loss, up/down conversion loss, connector patch losses, etc.) Power leaking during transmission is a big issue right now.
(b) Charging loss (efficiency is not always good, that's why your battery is hot after charging)
(c) Battery Conversion loss
My point is that electric cars is not the answer. It's to improve efficiencies, whether it's car eff, or power plant (unlikely), or just plain get rid of all the power leakage during transmission etc..
(Anyway, maximing aerodynamics, size, noise will improve efficiency, whatever the engine
Right. that's my point exactly.
Thermodynamics prevents us from getting anything more than 50% (the theoretical limit is about 60% depending on in/out temp ratios). AND That is assuming that you everything you put in is converted to heat, which is impossible.
(i.e. there are two losses : thermodynamic 2nd law loss, which is theoretical limit due to entropy, and the "conversion loss" which states you can't get 100% all the stuff you put in into energy, which depends on the H to C ratio of your fuel.)
>90% you must be kidding.
There is something called the 2nd law of thermodynamics. DEpending on what kind of heat cycle your generator uses, and the in/out temperature ratios. Even with all sorts of reheaters, coolers, flue-gas turbines, that's a number only God (if She is there) can achieve.
And She has plenty of energy in Hell.
(a) Agree on the Solar Powered cars. Big batteries with solar-powered plants. (Imagine big "Gas" stations with solar panels.)
(b) Disagree on the efficiency of the power plants. Power plants efficiencies are almost maxed-out : it's a well developed science. And the efficiency max depends on the fuel you burn. The primary fuel, coal (because it's hard to put coal into anything smaller than a big power plant), has VERY low conversion efficiency. Even if you consider plants that burn gas or natural gas, the transmission loss can be as much as 40% (some cases more for long hauls). That will wipe out any advantage you get by tuning your system (which you probably can't).
People here seems to think that by putting stuff other than gas into their cars can (1) save the environment (2) save costs (3) look cool.
But this is all a myth, just something to make us feel good. The fact is that _cars burn fuel_ to move whatever the fuel is.
Electricity? Sure plug in your batteries into your house jack to charge em up! No Gas? WRONG! How the hell do the electricity gets to your jack anyway? It's coal, burnt at your nearest power station. That's more damaging to the enviro then gas.
Natural gas? That's still fuel. And it costs money and energy to either (a) compress them (b) process them. (I know, I work in a gas compression facility before.) That's fuel burned, kiddo. The savings to the environment is minimal.
(Now methanol is cool : it's made of sugarcane which is eminently renewable.)
The future is not about "what fuel you burn". It's about "how efficient is your engine". Natural gas has higher Hydrogen to Carbon ratio then gasoline, so they are more efficient. So is methanol. But NOT ELECTRICITY (unless it is solar powered. but solar powered cars are not going to be powerful enough since nature puts a limit on the efficiencies of GaAs solar cells at 25%.)
What do reviewers get for giving good reviews
on Linux? Free Redhat 6.2s? Free Mandrake Distro?
How about a free beer with Linus Torvalds?
Beside, non-biased reviewers don't exist. Recall the old adage : one man's Windows is another man's Linux.
After the breakup, RSA (Russian Space Agency) decided to build a replacement for Baikanour inb odny.htm)
Svobodny. (http://www.fas.org/spp/guide/russia/facility/svo
Problem is that they ran out of cash so that place is right now half-completed.
The many posts about launching nearer to equator is better is true only for near equatorial launches (like the ISS which is in a SHuttle orbit of about 25deg inclination). For other polar launches (>67 deg inclination), the higher up you are in latitude, the better. Plesetk is then used for such launches if they can (much like the VDBAFB is used for such launches in the US.) The fuel savings can be tremendous (up to 10%.)
They have the biggest database of all US and
foreign nationals.
They know your scores (remember that 450 on
maths?), they know your address, they have your
essays (that rant you wrote about the Pope?),
they have everything to totally wreck your life...
All in the name of education of course
Any translaters?
Gimme the good bits only!
Of course not :) it's 2 bits per Hz.
Define bandwidth.
:)
......
Are you talking about absolute carrying capacity
per Hz? That's 2 bits per Hz (there is some law
that proves it but I can't recall what's the name), IF you just do "up-down" as bit 1 and bit 0. of course there is such schemes such as using a step scheme such as to squeeze 2^n bits per Hz (with n = # steps) out but they run into s/n problems.
You can go higher and higher frequencies if you wanna more juice. You pay for higher frequencies with more power to increase s/n of your signal. So as long as you have power, you can go as high as you want. The ceiling? I bet it's the melting temperature of your transmitter
OTOH, if your "bandwidth" means the fuzzy idea of "data carried", used by internet talking heads and news anchor people, then
(a) magnotometer ok (b) you really need to land on the moon to be sure (c) you need good altitude and attitude control systems. (Doppler from earth don't work since the far side of the moon is not sighted)
Things to learn :
(a) How do we get lunar magnetic fields?
(b) Where and how much is water ice on the moon?
(c) WHat is the Moon's gravitational field? (An important problem : we still haven't found what it's call "fix orbits" on the moon since we have not completely map the grav. field to high enough resolution)
These there problems would probably take a dedicated unmanned mission each, and (b) probably take a manned mission.
So my dear friend, the moon is a Very interesting place.
Just like the Russians launch Comrade Gagarin
up to space for "Russian Pride", the Americans
land Mr Armstrong ont he moon for "American Pride"
etc.etc.etc..
If you wait to solve every problem on Earth before trying to do something else out of Earth, you'll be dead with overpopulation in a few decades.
So the compressing is done on hardware, cool.
But since once compressed, we can't compress
them any further, does this mean that any
software compression to increase mem space is
no longer usable?
I like extra MB, but let's hope that they
actually increase the physical storage space instead of just increasing "logical" storage.
A lot of credit should be properly accorded to the sequencers of course.
Granted, sequencing is so routine that it can be done by a bunch of monkeys (the quote's Jim Watson's, not mine so go yell at him). But that's only half the story : the hard part is getting putting together the system that allow the bunch of monkeys to sequence them. The computers, the algorithms, the $$$$, the political will, and the dedicated bunch of people who are doing admittedly tedious work (akin to copying out the Encyclopaedia Brittanica in Greek without knowing what Greek is.)
So, we should accord them the highest honours for pulling it off.
"NetBSD is the world's most portable operating system,"
:):)
Interesting. What kind of claim is that?!
I would say that Un*x is the most portable operating system.....but theyn it's a PR so some PR (pun intended) is needed.
I want those damn beachballs
Gyroscopes are needed for attitude/pointing control, and has no relevant to chips i.e. you can't replace a gyro with a chip (a laser gyro is still a gyro).
:)
Russians build things big out of historical/cultural reasons : their engineering is very robust and they do not often "go for the last mile" like western engineers do.
Russian efficient boosters are a Myth, their boosters are less efficient than most western boosters. The numbers they are throwing about are "fudged" in the sense that they add "back pressure thrust" to the numbers, while the standard western way of calculating efficiencies do not do that.
The cheapness of their launches is due to
(a) their rockets are cheap because their labour/material/tax/overhead are cheap
(b) they need to be cheap to compete with the protected western markets (eg. NASA forces NASA funded projects to go on American launchers.)
(c) they have lots of "cheap ex-ICBMS" converted to LV and are selling them, all due to the START treaty (in fact they have a LV call "START-1", a converted SS-21)
Any questions?
That depends on your unit. In addition, you can build your own GPS receivers that bypass those. You can get download the specs from the net from the NRO site.
Another question is that will DELL/RH/IBM support it and is the cost of support factored into the preloaded box?
Finally, here's a multiple choice question :
Q: Why is IBM/DELL shipping boxes with Linux instead of Windoze?
(a) They want to piss off Bill Gates (nah nah nah nah, your's monopoly's gone!)
(b) They listen to consumer demands
(c) They play the "cool" card and hope to ride the linux-association stock craze
(d) A Dell middle manager noticed that an unofficial desktop running linux was more stable (sic)