Memetics, however, is a science, unlike sociology. It's no more scientific than sociology. For a start, nobody has come up with a robust definition for a meme, it's just waffle. Genetics have things like DNA which are a repeatably measurable and remarkably useful natural encoding. memes, as far as I know, are nothing more than a vague idea of an idea which is transmissible.
As we're predicating on a space elevator we can assume a greater level of automation than currently used. Building big things in space is much easier as you don't have to deal with gravity. There is plenty of material floating around in asteroid belts and whatnot.
I don't think it is going to be that hard, if we can avoid all dying here first;)
Once you're in space and self-sufficient in terms of energy and support (i.e. nuclear power of some sort, complete nutrient recycling), travel is quite straightforward (solar sails, ion drives, that sort of thing). There's no hurry.
Octane is all about preignition and flame propagation. It has nothing to do with energy density. Ethanol has an octane of over 100 yet is considerably less energy dense.
Pumped water is not really an option unless you have a convenient supply of water and a large mountain or mine system.
Supercapacitors are very low energy density - you'd need a room full of supercaps to replace a Lead acid car battery.
The most important advantage of coolth storage is that it is only a software change - you don't need to buy any new power handling system, just reprogram the thermostat. There are other similar demand management systems - electrochemical smelters can often vary their electricity consumption between 'just staying warm' and 'pedal to the metal' and use vast amounts of electricity. Once demand side metering becomes big, we'll see lots of this sort of mitigation.
I'm sorry, I'm not following your maths here. We have a choice - either store the energy in say a battery (with 50% roundtrip), or store it as extra coolth.
Whatever the losses are, the 1 degree change as suggested would result in a 3% change in them (assuming linear heat transfer, a reasonable assumption here). So if 5% per hour results in 1-(1-0.05)^12=0.46 losses in 12 hours then dropping the temperature 1 degree will result in 1-(1-0.05*1.03)^12 = 0.47 loss in 12 hours - 2.2% more. If that energy were stored in a battery it would have resulted in a virtual loss of 50%, in this case we're looking at a virtual loss of 25%. If we take the continuous case (exp) we get a virtual loss of 2.1% (98% efficient).
The fact that the article says that a 1C change is sufficient to keep temps below the required value for the next day suggests that your assumptions are wildly off? I guess that the thermal mass is vastly greater than the losses (time constant) as the time constant increases the efficiency moves towards 1. Consider that you have maybe a thousand tonnes of ice surrounded by a wall of R(metric) 3. Back of the envelop suggests 6kW heat losses and storage of 2.1GJ for a time constant of roughly 4 days per degree C.
We're talking about a variation of 1C at -20C. Assuming an average outside temp of say 10C we're looking at a variation in losses of 3%. You are not going to find a battery, flywheel, fuelcell or pumped hydro system with a round trip efficiency of 97%.
The idea is a perfectly reasonable way to store energy, and the cost per Joule stored is going to be basically nothing compared to any other system.
We might use the oil for making plastics, even if there is more energy required to extract than is provided. That energy might be provided by renewables, nuclear or geek slaves on treadmills.
I think he means that the amount of money made by taxing MJ use is nothing on the amount of money made by selling of small time dealer's complete assets.
I thought that a common ground for all your equipment should be OK.
Nup, your tiny signal ground wires make excellent antennas and shorted turn transformers around your power. The current in ground loops can be surprisingly large, certainly enough to stuff your signals:-(
Sorry, I thought we were talking about 100 years ago. Today some BLDC motors are indeed just induction motors with less than ideal AC sources.:) Others are permanent magnet motors (which require suitably high gauss robust permanent magnets).
A big issue is grounding - you'll need isolating powersupplies or you'll have no end of trouble with signal lines. How do I know this? I built exactly what you propose and I ended up using isolating DC-DC converters. I use 24Vish so I can use two gel cels as backup. Because my system was only a prototype the converters ended up costing more than wall warts (not to mention the main power supply). Mass made they would be much cheaper as the transformers are tiny and they are thus a lot smaller than wall warts. I got a 90% decrease in power consumption (most of the power consumption with my wall warts was magnetizing current). My little converters have a standby power of about 1mW compared to 2.5W for a good wall wart (I've got one that uses 25W with no load!).
My total power consumption of all my wallwarty things has dropped from 68W to 3W in standby (no load). This makes a big difference when your power is RAPS (about 6 solar panels worth, or $3600). I also avoid the need to go via 240V allowing my inverter to switch to low power mode.
However, a significant advantage of AC is three phase power, which efficiently shares the power through three conductors. This alone is a major reason why more power lines haven't been upgraded to HVDC (with high power transmission lines the limiting factors are insulator breakdown and sag). There are various schemes which rotate the conductor pairs around to even out the heat, but then you start asking why they don't just use three phase AC, especially with the issues of dV/dt losses on the transitions.
AC induction motors are more efficient than DC motors - that's why all modern electric and hybrid cars use them and an inverter rather than a DC motor with PWM. I don't know why, could be something to do with back emf limiting top torque?
Modern switchmode powersupplies are designed to have low power factor (by law). Wall warts do not provide this guarantee, so will actually result in worse power factor for the same demand (and hence worse efficiency).
Australia's grain yield (one of the biggest exporters in the world) has been declining for 20 years now. Most of the improvements in crop yield have been by inventing better ways to convert cheap oil into food. If oil is running out (which seems to be the motivator for this approach) then I expect there will be an order of magnitude decrease in yield. Why?
* fertilizer derived from oil * herbicide derived from oil * insecticide derived from oil * energy intensive tilling/harvesting practices, derived from oil * bulk shipping, powered by oil
then we have the down-sides of modern agriculture:
* dry-land salinity * water rights * habitat destruction * erosion (kansas has lost 3m of topsoil in the last 50 years) * escalating pests, including endless foreign invaders * foreign ownership of farms leading to inefficient management
I wish I could believe what you do, but having just spent 3 months looking at the situation in the WA wheat belt, I am very pessimistic of the short term future. Farms are currently converting all profits to chemical support and are still losing money every year.
Add to this the probable reduction in rainfall in our largest grain growing areas (former soviet union, south africa, WA wheatbelt and canadian plains) due to changes in the atmosphere and the situation is rather grim.
Re:Where's the need come from?
on
Water From Wind
·
· Score: 1
Tanks are great..... But I believe they were actually illegal in the Brisbane metro area 10 years ago: they promoted mosquito breeding etc..... Pity
Yeah, ditto melb.
Re:Where's the need come from?
on
Water From Wind
·
· Score: 1
but water storage solutions haven't really grown at the same rate during that time - mainly due to environmental concerns and NIMBYism - not to mention the economics of building dams.
The lack of rain and suitable river catchments might be related too?
You're spot on about the tanks though. If we had had the push we're seeing currently for tank 10 years ago there would be no problem right now.
Re:Where's the need come from?
on
Water From Wind
·
· Score: 1
You can use osmotic membranes, deep sea pipes and the pressure differential between the salt water and the freshwater column to produce freshwater and energy. The pipes are big though.
Slashdot Mirror
It's annoying having curved walls - you need lots of custom built furniture.
I'd like to try living in one for a while first.
Like these:
:)
http://en.wikipedia.org/wiki/Monolithic_dome
http://www.monolithic.com/
Apparently it took a demolition team a week to knock one down with high exposives and a wrecking ball
Actually, you can only extra 2/3 of the energy from the wind or water (which led Carnot to his famous cycle).
If you say so.
Memetics, however, is a science, unlike sociology.
It's no more scientific than sociology. For a start, nobody has come up with a robust definition for a meme, it's just waffle. Genetics have things like DNA which are a repeatably measurable and remarkably useful natural encoding. memes, as far as I know, are nothing more than a vague idea of an idea which is transmissible.
As we're predicating on a space elevator we can assume a greater level of automation than currently used. Building big things in space is much easier as you don't have to deal with gravity. There is plenty of material floating around in asteroid belts and whatnot.
;)
I don't think it is going to be that hard, if we can avoid all dying here first
Once you're in space and self-sufficient in terms of energy and support (i.e. nuclear power of some sort, complete nutrient recycling), travel is quite straightforward (solar sails, ion drives, that sort of thing). There's no hurry.
Octane is all about preignition and flame propagation. It has nothing to do with energy density. Ethanol has an octane of over 100 yet is considerably less energy dense.
Pumped water is not really an option unless you have a convenient supply of water and a large mountain or mine system.
Supercapacitors are very low energy density - you'd need a room full of supercaps to replace a Lead acid car battery.
The most important advantage of coolth storage is that it is only a software change - you don't need to buy any new power handling system, just reprogram the thermostat. There are other similar demand management systems - electrochemical smelters can often vary their electricity consumption between 'just staying warm' and 'pedal to the metal' and use vast amounts of electricity. Once demand side metering becomes big, we'll see lots of this sort of mitigation.
I'm sorry, I'm not following your maths here. We have a choice - either store the energy in say a battery (with 50% roundtrip), or store it as extra coolth.
Whatever the losses are, the 1 degree change as suggested would result in a 3% change in them (assuming linear heat transfer, a reasonable assumption here). So if 5% per hour results in 1-(1-0.05)^12=0.46 losses in 12 hours then dropping the temperature 1 degree will result in 1-(1-0.05*1.03)^12 = 0.47 loss in 12 hours - 2.2% more. If that energy were stored in a battery it would have resulted in a virtual loss of 50%, in this case we're looking at a virtual loss of 25%. If we take the continuous case (exp) we get a virtual loss of 2.1% (98% efficient).
The fact that the article says that a 1C change is sufficient to keep temps below the required value for the next day suggests that your assumptions are wildly off? I guess that the thermal mass is vastly greater than the losses (time constant) as the time constant increases the efficiency moves towards 1. Consider that you have maybe a thousand tonnes of ice surrounded by a wall of R(metric) 3. Back of the envelop suggests 6kW heat losses and storage of 2.1GJ for a time constant of roughly 4 days per degree C.
We're talking about a variation of 1C at -20C. Assuming an average outside temp of say 10C we're looking at a variation in losses of 3%. You are not going to find a battery, flywheel, fuelcell or pumped hydro system with a round trip efficiency of 97%.
The idea is a perfectly reasonable way to store energy, and the cost per Joule stored is going to be basically nothing compared to any other system.
We might use the oil for making plastics, even if there is more energy required to extract than is provided. That energy might be provided by renewables, nuclear or geek slaves on treadmills.
I think he means that the amount of money made by taxing MJ use is nothing on the amount of money made by selling of small time dealer's complete assets.
I thought that a common ground for all your equipment should be OK.
:-(
Nup, your tiny signal ground wires make excellent antennas and shorted turn transformers around your power. The current in ground loops can be surprisingly large, certainly enough to stuff your signals
Sorry, I thought we were talking about 100 years ago. Today some BLDC motors are indeed just induction motors with less than ideal AC sources. :) Others are permanent magnet motors (which require suitably high gauss robust permanent magnets).
A big issue is grounding - you'll need isolating powersupplies or you'll have no end of trouble with signal lines. How do I know this? I built exactly what you propose and I ended up using isolating DC-DC converters. I use 24Vish so I can use two gel cels as backup. Because my system was only a prototype the converters ended up costing more than wall warts (not to mention the main power supply). Mass made they would be much cheaper as the transformers are tiny and they are thus a lot smaller than wall warts. I got a 90% decrease in power consumption (most of the power consumption with my wall warts was magnetizing current). My little converters have a standby power of about 1mW compared to 2.5W for a good wall wart (I've got one that uses 25W with no load!).
My total power consumption of all my wallwarty things has dropped from 68W to 3W in standby (no load). This makes a big difference when your power is RAPS (about 6 solar panels worth, or $3600). I also avoid the need to go via 240V allowing my inverter to switch to low power mode.
However, a significant advantage of AC is three phase power, which efficiently shares the power through three conductors. This alone is a major reason why more power lines haven't been upgraded to HVDC (with high power transmission lines the limiting factors are insulator breakdown and sag). There are various schemes which rotate the conductor pairs around to even out the heat, but then you start asking why they don't just use three phase AC, especially with the issues of dV/dt losses on the transitions.
AC induction motors are more efficient than DC motors - that's why all modern electric and hybrid cars use them and an inverter rather than a DC motor with PWM. I don't know why, could be something to do with back emf limiting top torque?
Modern switchmode powersupplies are designed to have low power factor (by law). Wall warts do not provide this guarantee, so will actually result in worse power factor for the same demand (and hence worse efficiency).
Wow, I didn't know people could be so completely clueless!
r ces_and_consumption)
For your information, the amount of energy humans use currently is 15TW
(http://en.wikipedia.org/wiki/Energy:_world_resou
The sun dumps 17400 TW onto the earth. (http://en.wikipedia.org/wiki/Solar_radiation)
So Anthropogenic energy use is less than 1/10000 of the total heat from the sun (ignoring geothermal and tidal energy).
Australia's grain yield (one of the biggest exporters in the world) has been declining for 20 years now. Most of the improvements in crop yield have been by inventing better ways to convert cheap oil into food. If oil is running out (which seems to be the motivator for this approach) then I expect there will be an order of magnitude decrease in yield. Why?
* fertilizer derived from oil
* herbicide derived from oil
* insecticide derived from oil
* energy intensive tilling/harvesting practices, derived from oil
* bulk shipping, powered by oil
then we have the down-sides of modern agriculture:
* dry-land salinity
* water rights
* habitat destruction
* erosion (kansas has lost 3m of topsoil in the last 50 years)
* escalating pests, including endless foreign invaders
* foreign ownership of farms leading to inefficient management
I wish I could believe what you do, but having just spent 3 months looking at the situation in the WA wheat belt, I am very pessimistic of the short term future. Farms are currently converting all profits to chemical support and are still losing money every year.
Add to this the probable reduction in rainfall in our largest grain growing areas (former soviet union, south africa, WA wheatbelt and canadian plains) due to changes in the atmosphere and the situation is rather grim.
You have: 22kHz
:)
You want: rpm
* 210084.52
(still, 200000rpm is rather fast
Tanks are great..... But I believe they were actually illegal in the Brisbane metro area 10 years ago: they promoted mosquito breeding etc..... Pity
Yeah, ditto melb.
but water storage solutions haven't really grown at the same rate during that time - mainly due to environmental concerns and NIMBYism - not to mention the economics of building dams.
The lack of rain and suitable river catchments might be related too?
You're spot on about the tanks though. If we had had the push we're seeing currently for tank 10 years ago there would be no problem right now.
You can use osmotic membranes, deep sea pipes and the pressure differential between the salt water and the freshwater column to produce freshwater and energy. The pipes are big though.
Australian plastic currency is printed on polypropene.
http://en.wikipedia.org/wiki/AUD