In the olden days, if you wanted nearly pure ethanol, you would first use simple distillation it to remove most of the water. Arguably, this is boiling the ethanol from the water. This gets you to about 96% purity, but it is impossible to remove the last 4% of the water with simple distillation. To get to nearly pure alcohol, you would add benzene or cyclohexane to the 96% pure mixture and continue boiling. The benzene from a three-way azeotrope and removes the last of the water by boiling. In this procedure, the pure alcohol is what is left over after the water, benzene and some of the alcohol is boiled away. You literally do "boil the water from it".
These days, molecular sieves are employed to remove the last of the water.
You are partly right, but things are not quite that bad.
You are right in that you don't want to compress air into a hot tank and then allow the tank to cool. That is energy lost. But just because gas will get hot if you compress it quickly in an insulated container does not mean you have to _let_ it get hot as you compress it.
If you compress the gas in such a way that it does not get hot (be efficient in removing the heat of compression) and expand the gas in such a way that it does not get cold (be efficient in re-supplying heat) the efficiency of compressed gas as a storage system approaches 100%.
It seems somewhat contrary, but to be efficient you either need to preserve all the heat of compression (the compressor and tank are perfect heat insulators) or absolutely none of it (the compressor and are perfect heat conductors to ambient). Anything in between results in inefficiency.
We add an additional 4% each year and there is nothing to balance that. We can also look at isotope ratios (fossil fuels are ancient carbon). It is our CO2.
There is a huge issue with scale here. Lets do some rough calculations. A person needs 50^2 m of green space lit 1/3 of the time. To duplicate sunlight, we need about 1kW/m^2. Assume we have an LED that is about 10% efficient. That comes out to about 167kW per person. RTG like those on deep space probes have outputs measure in Watts, not kilowatts. RTGs don't scale well. If you need these kinds of outputs, you will be looking at conventional reactor. Getting rid of the excess heat is going to be a real challenge.
LEDs are inefficient. Photosynthesis is inefficient. If you need to make oxygen from water and you have electricity, there are much more efficient ways of doing it than using LEDs and plants.
You also would not store the power to run the LEDs, you would store plant products that are created during the two weeks that there is light.
People change. I doubt that 60% of 79-years-olds would opt for a lifespan of 80 years. On the other hand, twenty year olds are idiots. They probably think that 80 is impossibly old and cannot imagine that it is worth living beyond 80.
I want to die when I am ready. I am not ready now. I probably won't be when I am 80. Put me down in the 'forever' catagory and I will let you know.
Even IFR produce some isotopes with negligible neutron cross section and long half lives. You can attempt to minimize the production of these byproducts, but you cannot eliminate them entirely. Once created, time is the only thing that will eliminate them. You cannot burn them up in any reactor.
That said, nuclear waste is largely a red herring. It is true that it is dangerous and will remain dangerous for many centuries, but it is not really that hard to build storage facilities that will prevent the waste from entering the biosphere for several millennia. You put the waste in an inert container, bury it in the ground and leave it alone.
The danger comes from operating reactors. Here, I am not exactly sure how IFR are really any safer than more conventional reactors once scaled to commercial sizes. If you lose power, you have to remove gigawatts of power from the core for several days or bad things will happen.
Current Federal Gas Tax is 18.4 cent per gallon, average state tax is 31.1 cents per gallon. Doubling these will add less than 50 cents to the cost of a gallon of gasoline.
Fuel taxes and tolls only ever covered a portion of the cost of road construction.
Many of the roads and bridges need to be expanded to handle higher volumes of traffic or meet higher construction standards. The cost of acquiring land has increased dramatically.
Fuel tax is on a per gallon basis, not on a percentage. As gas prices increase, the tax does not. Road construction is fuel-intensive. The 18.4 cent Federal tax was enacted when oil was about $20 a barrel. Oil is now around $100 a barrel. Gas taxes really need to go up by nearly a factor of 5 to cover this.
Cars get much better gas mileage now than they did a few years ago. This means they are paying less tax per mile.
You could still cool the servers with treated outside air (or 110deg water or whatever). You then insulate the server racks and cool the room with conventional AC. The trick then is that the AC only needs to handle the heat from the servers that leaks through the insulation rather than the power being dissipated by the servers.
The Apple IPO was in 1980 for $22/share. $666.66 would have purchased a little over 30 shares. Since then, it has paid a few dollars in dividends (which can be ignored) and split 2:1 three times. You would now own 240 shares, and it closed today at $574 for a value of $137,000.
Gas powered heat pumps can be more than 100% efficient as well. The natural gas to runs an ICE that provides mechanical power for a compressor. You recover exhaust heat and your overall exhaust is actually colder than ambient. Current efficiency's range from about 120 to 150%. A small generator can be attached to the shaft as well and provide enough power for control and to possibly operate a blower. It is a neat system, but they are not catching on.
Re:Had to do with his management style, not policy
on
NRC Chairman Resigns
·
· Score: 1
There is a lot of volatile, dangerous stuff like Cs-135, Cs-137, and Sr-90 with half lives short enough to be hot as hell and long enough to be around for a while that you can't burn up for fuel because it has almost no neutron cross section. I find the idea that these can be efficiently transmuted in a MSR is highly optimistic.
When I put a Blu Ray disk in to the player the booting up and handshaking takes several minutes to complete. I could rewind an entire VHS tape in the time it takes to start working. What is it doing during all that time? I am betting that is has a LOT to do with anti-piracy measures. I would love to have a player that simply played the damn movie that I paid for, not that I am buying many Blu Rays there days.
Check out Ramsey Electronics sometime. I have build several of there kits with my kids. My only gripe with them is that they do not offer the source code for any of there microcontroller-based projects, and seemed to get offended when I asked.
Have you ever calculated the amount of power being delivered through a gasoline filling hose? Gallon of gas = 1.3 x 10^8 Joules. 20 gallons of gas in 5 minutes = (20 * 1.3 x 10^8) / (5 * 60) = 8.7Megawatts. That is 876 Amps at 10,000 Volts. Liquid fueled cars are going to be around a long, long time.
3 days a week at 60 miles from her house is 360 miles a week of driving just for work. That is 18 gallons of gas a week at 20 MPG. 18 gallons a week at $5 gallon = $80/week = $360/month just for work. And I would be that is not the only driving she is doing.
It may be well worth trading in her current car for a newer used car that gets much better gas mileage. Eventually, even well cared for used cars will require expensive repaires. Also factor in the time savings of stopping for gas less often.
A Volt would not be a good fit for her with the distances she drivesk, you really need to have a commute that is near the electric range fo the vehicle.
The Volt has an 8-year, 100,000 mile warrenty on the batteries. I personally know of several 10-year-old plus Priuses that are still working well on the original batteries. Stop spewing nonsense about the batteries needing to be replaced every 5 years.
It takes about 15TW to power modern civiliation. That is about 500 exajoules of energy annually. In terms of mass, that works out to about 5,500 kilograms per year. One kilogram of mass converted directly to energy would last about 40 minutes.
Not octane, isooctane!
on
Is E85 Dead Now?
·
· Score: 3, Interesting
n-octane has an octane rating of about -10. However, 2, 2, 4 - trimethyl pentane (an isomer of n-Octane, sometimes called isooctane) has an octane rating of 100. Generally, the more branches and methyl groups a molecule has, they higher the octane rating. Small molecules of fuel also tend ot have higher octane ratings. Molecules with alcohol groups on them don't usually have octane ratings much different from a similar non-alcohol bearing group, but they tend to be liquids are useful temperatures and pressures. Both Ethane and Ethanol has an octane rating of about 100 (depends on the method used to measure it).
None of this has anything to do with they amount of energy you get out of a gallon or a kilogram of such a fuel. Diesle fuel has a higher energy content that gasoline per gallon (and per kilogram) and has a much lower octane rating (15-25).
Lasting longer? I have incandescent bulbs in my house that have seen daily use for the last 17 years. They may be much older than that, they were in the house when I bought it.
Edison's chief competitor was George Westinghouse, not Tesla. Tesla was too poor a business man to be a serious competitor.
Slashdot Mirror
In the olden days, if you wanted nearly pure ethanol, you would first use simple distillation it to remove most of the water. Arguably, this is boiling the ethanol from the water. This gets you to about 96% purity, but it is impossible to remove the last 4% of the water with simple distillation. To get to nearly pure alcohol, you would add benzene or cyclohexane to the 96% pure mixture and continue boiling. The benzene from a three-way azeotrope and removes the last of the water by boiling. In this procedure, the pure alcohol is what is left over after the water, benzene and some of the alcohol is boiled away. You literally do "boil the water from it".
These days, molecular sieves are employed to remove the last of the water.
Isn't that a form of propellantless drive? What if you exploited that to create a very large, very hot surface?
You are partly right, but things are not quite that bad.
You are right in that you don't want to compress air into a hot tank and then allow the tank to cool. That is energy lost. But just because gas will get hot if you compress it quickly in an insulated container does not mean you have to _let_ it get hot as you compress it.
If you compress the gas in such a way that it does not get hot (be efficient in removing the heat of compression) and expand the gas in such a way that it does not get cold (be efficient in re-supplying heat) the efficiency of compressed gas as a storage system approaches 100%.
It seems somewhat contrary, but to be efficient you either need to preserve all the heat of compression (the compressor and tank are perfect heat insulators) or absolutely none of it (the compressor and are perfect heat conductors to ambient). Anything in between results in inefficiency.
Motherboards are seriously cheap. I have never upgraded a motherboard without replacing the CPU, though I have replaced a few bad motherboards.
We add an additional 4% each year and there is nothing to balance that. We can also look at isotope ratios (fossil fuels are ancient carbon). It is our CO2.
http://www.skepticalscience.com/human-co2-smaller-than-natural-emissions-intermediate.htm
But can we do this after the Memphis-Huntsville-Atlanta section of I-30 gets planned and built?
There is a huge issue with scale here. Lets do some rough calculations. A person needs 50^2 m of green space lit 1/3 of the time. To duplicate sunlight, we need about 1kW/m^2. Assume we have an LED that is about 10% efficient. That comes out to about 167kW per person. RTG like those on deep space probes have outputs measure in Watts, not kilowatts. RTGs don't scale well. If you need these kinds of outputs, you will be looking at conventional reactor. Getting rid of the excess heat is going to be a real challenge.
LEDs are inefficient. Photosynthesis is inefficient. If you need to make oxygen from water and you have electricity, there are much more efficient ways of doing it than using LEDs and plants.
You also would not store the power to run the LEDs, you would store plant products that are created during the two weeks that there is light.
People change. I doubt that 60% of 79-years-olds would opt for a lifespan of 80 years. On the other hand, twenty year olds are idiots. They probably think that 80 is impossibly old and cannot imagine that it is worth living beyond 80.
I want to die when I am ready. I am not ready now. I probably won't be when I am 80. Put me down in the 'forever' catagory and I will let you know.
Even IFR produce some isotopes with negligible neutron cross section and long half lives. You can attempt to minimize the production of these byproducts, but you cannot eliminate them entirely. Once created, time is the only thing that will eliminate them. You cannot burn them up in any reactor.
That said, nuclear waste is largely a red herring. It is true that it is dangerous and will remain dangerous for many centuries, but it is not really that hard to build storage facilities that will prevent the waste from entering the biosphere for several millennia. You put the waste in an inert container, bury it in the ground and leave it alone.
The danger comes from operating reactors. Here, I am not exactly sure how IFR are really any safer than more conventional reactors once scaled to commercial sizes. If you lose power, you have to remove gigawatts of power from the core for several days or bad things will happen.
Would it take over if you were attempting to drive 90MPH through a residential zone? What about doing 35MPH through a residential zone?
Current Federal Gas Tax is 18.4 cent per gallon, average state tax is 31.1 cents per gallon. Doubling these will add less than 50 cents to the cost of a gallon of gasoline.
Fuel taxes and tolls only ever covered a portion of the cost of road construction.
Many of the roads and bridges need to be expanded to handle higher volumes of traffic or meet higher construction standards. The cost of acquiring land has increased dramatically.
Fuel tax is on a per gallon basis, not on a percentage. As gas prices increase, the tax does not. Road construction is fuel-intensive. The 18.4 cent Federal tax was enacted when oil was about $20 a barrel. Oil is now around $100 a barrel. Gas taxes really need to go up by nearly a factor of 5 to cover this.
Cars get much better gas mileage now than they did a few years ago. This means they are paying less tax per mile.
You could still cool the servers with treated outside air (or 110deg water or whatever). You then insulate the server racks and cool the room with conventional AC. The trick then is that the AC only needs to handle the heat from the servers that leaks through the insulation rather than the power being dissipated by the servers.
The Apple IPO was in 1980 for $22/share. $666.66 would have purchased a little over 30 shares. Since then, it has paid a few dollars in dividends (which can be ignored) and split 2:1 three times. You would now own 240 shares, and it closed today at $574 for a value of $137,000.
Gas powered heat pumps can be more than 100% efficient as well. The natural gas to runs an ICE that provides mechanical power for a compressor. You recover exhaust heat and your overall exhaust is actually colder than ambient. Current efficiency's range from about 120 to 150%. A small generator can be attached to the shaft as well and provide enough power for control and to possibly operate a blower. It is a neat system, but they are not catching on.
There is a lot of volatile, dangerous stuff like Cs-135, Cs-137, and Sr-90 with half lives short enough to be hot as hell and long enough to be around for a while that you can't burn up for fuel because it has almost no neutron cross section. I find the idea that these can be efficiently transmuted in a MSR is highly optimistic.
When I put a Blu Ray disk in to the player the booting up and handshaking takes several minutes to complete. I could rewind an entire VHS tape in the time it takes to start working. What is it doing during all that time? I am betting that is has a LOT to do with anti-piracy measures. I would love to have a player that simply played the damn movie that I paid for, not that I am buying many Blu Rays there days.
Check out Ramsey Electronics sometime. I have build several of there kits with my kids. My only gripe with them is that they do not offer the source code for any of there microcontroller-based projects, and seemed to get offended when I asked.
Have you ever calculated the amount of power being delivered through a gasoline filling hose?
Gallon of gas = 1.3 x 10^8 Joules.
20 gallons of gas in 5 minutes = (20 * 1.3 x 10^8) / (5 * 60) = 8.7Megawatts.
That is 876 Amps at 10,000 Volts.
Liquid fueled cars are going to be around a long, long time.
3 days a week at 60 miles from her house is 360 miles a week of driving just for work. That is 18 gallons of gas a week at 20 MPG. 18 gallons a week at $5 gallon = $80/week = $360/month just for work. And I would be that is not the only driving she is doing.
It may be well worth trading in her current car for a newer used car that gets much better gas mileage. Eventually, even well cared for used cars will require expensive repaires. Also factor in the time savings of stopping for gas less often.
A Volt would not be a good fit for her with the distances she drivesk, you really need to have a commute that is near the electric range fo the vehicle.
The Volt has an 8-year, 100,000 mile warrenty on the batteries. I personally know of several 10-year-old plus Priuses that are still working well on the original batteries. Stop spewing nonsense about the batteries needing to be replaced every 5 years.
Would a broke nose be an issue?
It is horrifying that it costs almost 2 cents an hour to game on an X-box?
This uses ferrimagnetic domains, not ferromagnetic domains. There is no external magnetic field, and you can't use a coil to read them.
It takes about 15TW to power modern civiliation. That is about 500 exajoules of energy annually. In terms of mass, that works out to about 5,500 kilograms per year. One kilogram of mass converted directly to energy would last about 40 minutes.
n-octane has an octane rating of about -10. However, 2, 2, 4 - trimethyl pentane (an isomer of n-Octane, sometimes called isooctane) has an octane rating of 100. Generally, the more branches and methyl groups a molecule has, they higher the octane rating. Small molecules of fuel also tend ot have higher octane ratings. Molecules with alcohol groups on them don't usually have octane ratings much different from a similar non-alcohol bearing group, but they tend to be liquids are useful temperatures and pressures. Both Ethane and Ethanol has an octane rating of about 100 (depends on the method used to measure it).
None of this has anything to do with they amount of energy you get out of a gallon or a kilogram of such a fuel. Diesle fuel has a higher energy content that gasoline per gallon (and per kilogram) and has a much lower octane rating (15-25).
Lasting longer? I have incandescent bulbs in my house that have seen daily use for the last 17 years. They may be much older than that, they were in the house when I bought it.
Edison's chief competitor was George Westinghouse, not Tesla. Tesla was too poor a business man to be a serious competitor.