most of the guns - I am using left eye and left hand. Bolt action rifles are simply inconvenient.
I'm left handed and right-eyed, but my left, non dominant eye has better vision. If I have my glasses with me I shoot light rifles and those with shaped grips right handed and heavier guns left handed. Without my glasses I always shoot left handed. I started left handed and then switched to this when I realised how much better I was using my dominant eye. I can cope with the bolt being on the right but shaped grips are just a pain in the backside. I tend to prefer Martini action as they're usually completely ambidextrous.
I'm American, but the first stick shift I learned to drive was British. Oddly, the only controls I had difficulty adjusting to were the turn signals and windshield wipers. I could never remember if they were mirrored or not.
I'm left-handed and British, I drive a manual car and change gear with my left hand. If I've got only one hand on the wheel it's usually my right but I'm cool with both. I've driven the occasional left-hand drive car and after half an hour or so I'm used to reaching on my right for the gear stick, likewise on tractors with the stick in the middle. I don't think it makes a lot of difference.
What I find hardest to get used to is the position of the indicators (turn signals) when I change between cars. The majority (but far from all) of cars on the road in the UK seem to have them on the left and the wipers on the right, I drive an older british-made car with indicators on the right and wipers on the dash and I get that one wrong more often than anything else. The other one is strangely enough the throttle travel, after driving a friends car for a while I get in mine and think it's gutless and underpowered, right until I realise/remember there's a full two inches more travel on the pedal:-)
Or, for a cheaper alternative, one of those digital photo frames that can play video as well as display pictures.
I like the digital photo frame idea for playing videos. Cheaper, less complicated and smaller than a laptop. I really wouldn't worry about powering it, throw the original brick in the box anyway but if we can't manage to provide a 12V dc supply in 25 years time we've got bigger problems.
Of course for storing video really long time put it on film and use the technicolour process - three monochrome prints will last far longer than a single colour print.
If you can make it truly isothermal then your efficiency is as good as the adiabatic method but that's even more difficult to do. If you go isothermal then you deliberately cool the air as you're compressing it, allowing you to store a greater amount of air in the same volume for a given pressure. Imagine vast heat exchangers dumping that extra heat into the environment. But to re-gain that energy you have to expand it isothermally as well, similarly large heat exchangers pulling the heat back in from the environment. The whole thing runs at constant temperature and, in the ideal case, without thermodynamic losses.
Unfortunately isothermal processes tend to be slow to give the temperatures time to equalise which isn't good for power. It's also hard to expand air isothermally when you want that expansion to happen in a turbine, right where it's a pain in the backside to put a huge heat exchanger.
The passengers wouldn't be happy if the train stopped and their coffee slid off the table
This is a much better use for tilting trains. Camber the track such that the trains don't need to tilt at their design speed but if the train has to run much slower on that track then they can tilt the opposite direction and make things more comfortable for the passengers.
Nuclear reactors have been used in space before, the soviets used them in some radar satellites. The shielding isn't really a problem once it's in space so a reactor could be designed with just enough shielding to contain the initial radioactivity of the fuel without worrying about shielding the much higher radiation levels once the reactor is operating. The shielding that it does have could also be jettisoned fairly early on in the mission.
I will agree however that RTGs are much more reliable and as such are desirable for deep space missions where the power requirements are not too high.
I remember reading in some sci fi book about a vault that was sealed by attaching a chunk of a long-lived radioisotope to the back of a tight fitting steel door such that the heat released caused the door to expand and jam tightly into the frame. The idea was that it could only be opened by a fairly advanced civilisation that was capable of artificial refrigeration, plus of course able to recognise what was needed. I always found that an intriguing idea although anyone sufficiently determined could probably get in anyway
Don't suppose anyone knows what book that was? I've been trying to find it for years now.
This is the USA, we don't do any of them metric units. So it wouldn't be meters of electricity, it would be a good old american measure, like BTU [emphasis added]
BTU as in British Thermal Unit? It's a unit of energy so you can measure your electricity consumption in it if you want. It'd be a bit inconvenient to calculate expected use unless all your appliances state consumption in BTU per fortnight or something.
If you don't have a problem with computer monitors at over 75 Hz then I'm surprised you do with any fluorescents. The old ones with magnetic ballasts flicker at double the mains frequency (so 100 or 120 Hz), the newer electronic ones drive the tubes at about 40 kHz and the persistence of the phosphor will even out any variations in light at those frequencies. Some tubes that are very nearly dead (burnt out cathode) might conduct in only one direction and give a mains frequency flicker that most people would notice but these should only be exceptional cases.
I'll agree with you on the spectrum though, although halogen is very similar to other incandescent lights. Given that humans can't perceive absolute colour I seriously doubt a slightly shifted black body spectrum would be noticeable apart from that when side-by-side with a conventional incandescent the halogen is slightly less yellow.
That is a good point however the problem with Apollo 1 was not just the pure oxygen atmosphere but the fact that it was at atmospheric pressure. Pure oxygen at 3 psi (the apollo capsules were at this pressure whilst in space) has the same partial pressure as air at atmospheric pressure and chemically behaves the same (including both fire and biological uses).
the losses in the CAES system are due to the fact that it is a non-adiabatic process
the solution you propose is isobaric (constant pressure) and isothermal (constant temperature)
Either an adiabatic or an isothermal process will allow high efficiency. In the adiabatic process the heat from compression is stored in the air and in principle no energy is lost through the compression and decompression. In an isothermal process all of the extra heat from the compression is transferred to some external reservoir (ocean, atmosphere, etc). If this heat is transferred back to the air when decompression occurs the air leaves the system at its original temperature (as for an adiabatic process) and no energy is lost. An isothermal system can actually store more energy since the stored air is at low temperature and hence a greater quantity may be stored within a given volume and pressure limit.
In real systems what happens is heat is lost during compression and in storage and that heat is not fully returned to the system during decompression. The air leaves at a lower temperature and energy is lost. Some compressed air energy storage schemes have resorted to using natural gas to reheat the air since heat exchangers for a true isothermal process are impractically large.
But what happens if the train breaks down? Will people need space suits to get to the nearest exit from the tunnel?
Maybe oxygen masks.
Connected to a tank of oxygen sufficiently large to fill the entire tunnel close to 1 atmosphere of pressure?
Now that is a good idea. Since such a tank would be large we could store it external to the train and have valves along the length of the tunnel which can be remotely operated from on board the train. Perhaps we could confine this external source of air gravitationally rather than in a tank and call it the atmosphere?
Seriously though, that's all that would be needed. You could include one oxygen mask for someone to go out and open the next valve down if it gets stuck or something like that. Bear in mind that 3 psi isn't that low - humans are quite happy at that pressure if they're breathing pure oxygen - that's what was used on the apollo moon missions.
Now, before people freak out - Tritium is a beta emitter. Barely any electrons make it through the boro-silicate glass or plastic secondary container. Those that do are unlikely to penetrate my first layer of skin.
Effectively zero electrons make it through, it's probably a less significant effect than the tritium diffusing through the glass (which is also insignificant). What does escape through the glass is bremstrahlung, X-ray radiation produced when the electrons strike the glass wall of the container. It's still too weak to be a health risk and the plastic outer can will absorb quite a bit since they're very low energy but it is detectable. If you took the inner glass capsule out and placed it on a sheet of photographic film wrapped in foil to block the light and came back in a few months to develop it you'd see a dark line where it was sitting.
I have a couple of these, one on my keyring and one on my penknife - they're very useful to tag things so you can find them if you drop them and the keyring one also helps me find the right key in the dark.
I suspect they mean 17,000 atoms per liter. Since a liter of water has about 3.33*10^23 molecules or 6.66*10^23 hydrogen atoms, That would make the tritium concentration 1 per 3.91*10^19 hydrogen atoms. I wouldn't count on getting rich by collecting the tritium.
I was about to do that conversion, I'm not sure if the silly “parts per litre” units are something used in the industry to avoid exponential notation or something made up by the greenpeace press office to make the concentration sound a lot bigger than it is. I'm guessing to actually measure this they'd measure the activity of the water per unit mass (Bq kg^-1) and convert but I suppose they could also do it with a mass spectrometer which would also show up any other contamination.
I haven't been there for a number of years but last time I was there they had a large number of technology related exhibits plus a lot of general science related ones, all aimed at children. They build (or at least used to build) most of it in a workshop on site and seem to have a reasonable turnover of exhibits - as a child I would often go there and find new things that had been added since my last visit.
Offhand I can't remember many specific examples but I believe they had a “network” based on routing coloured balls representing the data, an exhibit on batteries where the children could compare the outputs from cells made with different metals (copper, steel, aluminium, zinc) and electrolytes (vinegar, cola, etc). There was also a pile of parts that if assembled according to the diagram would create a steam engine which could be run on compressed air, a demonstration of Pythagoras' theorem using volumes of liquid and so many more which I have forgotten.
That first issue (needing to right click to make the thing that was pasted visible) has never happened to me. When I paste stuff in it appears without messing about so I don't know what's going on there. For the second bit try going Edit->Paste as new image.
With regards to it being removed from the default installation I think it may be a mistake, it's very nice having a good image editor instaled by default but then I don't think it really matters because anyone who wants it can still install it easily.
It was a simple repair to make, but had he been turning more sharply or the tractor had something more powerful than a 30 hp ford ten engine it would have rolled and he wouldn't have been there to make the repair. Easier to fix, but not any less dangerous (the spring that broke was at the carburettor end of the cable and lifting the pedal would only make the cable flex).
A friend of mine had the return spring on a mechanical throttle break. It happened as he was going around a corner and you have no idea how scary it is to have a tractor up on two wheels. Not really arguing for or against electronic throttles here but mechanical systems can have problems too.
Everyone here is going to talk about how outrageous it is for a supermarket to be charged for playing the radio, but the fact of the matter is that they use the radio to create a pleasant environment for their customers, which makes it a tool of commerce. Songwriters are the ones who get compensated for this, and rightfully so: people are using the fruits of their labor (music) to help sell merchandise.
I would agree maybe if they were playing prerecorded music like CDs but stop and think for a minute about the radio. The station already broadcasts the music and pays the fees, and if instead of playing the radio in your shop you gave every employee/customer a portable radio they could listen to with headphones that would be entirely legal. It is absurd that there's a difference between that and just playing it for everyone to hear (unless of course the true purpose of the law is to support the manufacturers of portable radios).
As a bonus if we didn't have this stupid rule call centres could just play a national radio station while they put you on hold rather than driving you insane with utterly crap annoying “music”
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most of the guns - I am using left eye and left hand. Bolt action rifles are simply inconvenient.
I'm left handed and right-eyed, but my left, non dominant eye has better vision. If I have my glasses with me I shoot light rifles and those with shaped grips right handed and heavier guns left handed. Without my glasses I always shoot left handed. I started left handed and then switched to this when I realised how much better I was using my dominant eye. I can cope with the bolt being on the right but shaped grips are just a pain in the backside. I tend to prefer Martini action as they're usually completely ambidextrous.
I'm American, but the first stick shift I learned to drive was British. Oddly, the only controls I had difficulty adjusting to were the turn signals and windshield wipers. I could never remember if they were mirrored or not.
I'm left-handed and British, I drive a manual car and change gear with my left hand. If I've got only one hand on the wheel it's usually my right but I'm cool with both. I've driven the occasional left-hand drive car and after half an hour or so I'm used to reaching on my right for the gear stick, likewise on tractors with the stick in the middle. I don't think it makes a lot of difference.
What I find hardest to get used to is the position of the indicators (turn signals) when I change between cars. The majority (but far from all) of cars on the road in the UK seem to have them on the left and the wipers on the right, I drive an older british-made car with indicators on the right and wipers on the dash and I get that one wrong more often than anything else. The other one is strangely enough the throttle travel, after driving a friends car for a while I get in mine and think it's gutless and underpowered, right until I realise/remember there's a full two inches more travel on the pedal :-)
Or, for a cheaper alternative, one of those digital photo frames that can play video as well as display pictures.
I like the digital photo frame idea for playing videos. Cheaper, less complicated and smaller than a laptop. I really wouldn't worry about powering it, throw the original brick in the box anyway but if we can't manage to provide a 12V dc supply in 25 years time we've got bigger problems.
Of course for storing video really long time put it on film and use the technicolour process - three monochrome prints will last far longer than a single colour print.
Having just spotted this post: http://news.slashdot.org/comments.pl?sid=2980517&cid=40664271 which links here: http://lightsailenergy.com/tech.html I've realised someone's found a way to make it nearly isothermal.
It's actually a pretty good idea, it uses the latent heat of evaporation of water mixed with the air to store the thermal energy
If you can make it truly isothermal then your efficiency is as good as the adiabatic method but that's even more difficult to do. If you go isothermal then you deliberately cool the air as you're compressing it, allowing you to store a greater amount of air in the same volume for a given pressure. Imagine vast heat exchangers dumping that extra heat into the environment. But to re-gain that energy you have to expand it isothermally as well, similarly large heat exchangers pulling the heat back in from the environment. The whole thing runs at constant temperature and, in the ideal case, without thermodynamic losses.
Unfortunately isothermal processes tend to be slow to give the temperatures time to equalise which isn't good for power. It's also hard to expand air isothermally when you want that expansion to happen in a turbine, right where it's a pain in the backside to put a huge heat exchanger.
You don't need to re-encrypt the drive every time the key changes, you simply re-encrypt the file containing the randomly generated key for the drive.
The passengers wouldn't be happy if the train stopped and their coffee slid off the table
This is a much better use for tilting trains. Camber the track such that the trains don't need to tilt at their design speed but if the train has to run much slower on that track then they can tilt the opposite direction and make things more comfortable for the passengers.
Nuclear reactors have been used in space before, the soviets used them in some radar satellites. The shielding isn't really a problem once it's in space so a reactor could be designed with just enough shielding to contain the initial radioactivity of the fuel without worrying about shielding the much higher radiation levels once the reactor is operating. The shielding that it does have could also be jettisoned fairly early on in the mission.
I will agree however that RTGs are much more reliable and as such are desirable for deep space missions where the power requirements are not too high.
I remember reading in some sci fi book about a vault that was sealed by attaching a chunk of a long-lived radioisotope to the back of a tight fitting steel door such that the heat released caused the door to expand and jam tightly into the frame. The idea was that it could only be opened by a fairly advanced civilisation that was capable of artificial refrigeration, plus of course able to recognise what was needed. I always found that an intriguing idea although anyone sufficiently determined could probably get in anyway
Don't suppose anyone knows what book that was? I've been trying to find it for years now.
every so often while I'm driving, I panic and wonder where I left my keys.
Me too, I also search my pockets for my phone whilst talking to someone on it.
This is the USA, we don't do any of them metric units. So it wouldn't be meters of electricity, it would be a good old american measure, like BTU [emphasis added]
BTU as in British Thermal Unit? It's a unit of energy so you can measure your electricity consumption in it if you want. It'd be a bit inconvenient to calculate expected use unless all your appliances state consumption in BTU per fortnight or something.
If you don't have a problem with computer monitors at over 75 Hz then I'm surprised you do with any fluorescents. The old ones with magnetic ballasts flicker at double the mains frequency (so 100 or 120 Hz), the newer electronic ones drive the tubes at about 40 kHz and the persistence of the phosphor will even out any variations in light at those frequencies. Some tubes that are very nearly dead (burnt out cathode) might conduct in only one direction and give a mains frequency flicker that most people would notice but these should only be exceptional cases.
I'll agree with you on the spectrum though, although halogen is very similar to other incandescent lights. Given that humans can't perceive absolute colour I seriously doubt a slightly shifted black body spectrum would be noticeable apart from that when side-by-side with a conventional incandescent the halogen is slightly less yellow.
That is a good point however the problem with Apollo 1 was not just the pure oxygen atmosphere but the fact that it was at atmospheric pressure. Pure oxygen at 3 psi (the apollo capsules were at this pressure whilst in space) has the same partial pressure as air at atmospheric pressure and chemically behaves the same (including both fire and biological uses).
the losses in the CAES system are due to the fact that it is a non-adiabatic process
the solution you propose is isobaric (constant pressure) and isothermal (constant temperature)
Either an adiabatic or an isothermal process will allow high efficiency. In the adiabatic process the heat from compression is stored in the air and in principle no energy is lost through the compression and decompression. In an isothermal process all of the extra heat from the compression is transferred to some external reservoir (ocean, atmosphere, etc). If this heat is transferred back to the air when decompression occurs the air leaves the system at its original temperature (as for an adiabatic process) and no energy is lost. An isothermal system can actually store more energy since the stored air is at low temperature and hence a greater quantity may be stored within a given volume and pressure limit.
In real systems what happens is heat is lost during compression and in storage and that heat is not fully returned to the system during decompression. The air leaves at a lower temperature and energy is lost. Some compressed air energy storage schemes have resorted to using natural gas to reheat the air since heat exchangers for a true isothermal process are impractically large.
But what happens if the train breaks down? Will people need space suits to get to the nearest exit from the tunnel?
Maybe oxygen masks.
Connected to a tank of oxygen sufficiently large to fill the entire tunnel close to 1 atmosphere of pressure?
Now that is a good idea. Since such a tank would be large we could store it external to the train and have valves along the length of the tunnel which can be remotely operated from on board the train. Perhaps we could confine this external source of air gravitationally rather than in a tank and call it the atmosphere?
Seriously though, that's all that would be needed. You could include one oxygen mask for someone to go out and open the next valve down if it gets stuck or something like that. Bear in mind that 3 psi isn't that low - humans are quite happy at that pressure if they're breathing pure oxygen - that's what was used on the apollo moon missions.
Anyone know why I get a blank white page with the words “None shall pass.” when I visit that link?
Now, before people freak out - Tritium is a beta emitter. Barely any electrons make it through the boro-silicate glass or plastic secondary container. Those that do are unlikely to penetrate my first layer of skin.
Effectively zero electrons make it through, it's probably a less significant effect than the tritium diffusing through the glass (which is also insignificant). What does escape through the glass is bremstrahlung, X-ray radiation produced when the electrons strike the glass wall of the container. It's still too weak to be a health risk and the plastic outer can will absorb quite a bit since they're very low energy but it is detectable. If you took the inner glass capsule out and placed it on a sheet of photographic film wrapped in foil to block the light and came back in a few months to develop it you'd see a dark line where it was sitting.
I have a couple of these, one on my keyring and one on my penknife - they're very useful to tag things so you can find them if you drop them and the keyring one also helps me find the right key in the dark.
I suspect they mean 17,000 atoms per liter. Since a liter of water has about 3.33*10^23 molecules or 6.66*10^23 hydrogen atoms, That would make the tritium concentration 1 per 3.91*10^19 hydrogen atoms. I wouldn't count on getting rich by collecting the tritium.
I was about to do that conversion, I'm not sure if the silly “parts per litre” units are something used in the industry to avoid exponential notation or something made up by the greenpeace press office to make the concentration sound a lot bigger than it is. I'm guessing to actually measure this they'd measure the activity of the water per unit mass (Bq kg^-1) and convert but I suppose they could also do it with a mass spectrometer which would also show up any other contamination.
http://www.intech-uk.com/folders/frontpage_welcome/
I haven't been there for a number of years but last time I was there they had a large number of technology related exhibits plus a lot of general science related ones, all aimed at children. They build (or at least used to build) most of it in a workshop on site and seem to have a reasonable turnover of exhibits - as a child I would often go there and find new things that had been added since my last visit.
Offhand I can't remember many specific examples but I believe they had a “network” based on routing coloured balls representing the data, an exhibit on batteries where the children could compare the outputs from cells made with different metals (copper, steel, aluminium, zinc) and electrolytes (vinegar, cola, etc). There was also a pile of parts that if assembled according to the diagram would create a steam engine which could be run on compressed air, a demonstration of Pythagoras' theorem using volumes of liquid and so many more which I have forgotten.
Another shameless attempt to get some free space: Click here and sign up and we'll both get an extra 250 MB.
Seriously though. Dropbox is great, I was dubious about it at first but it's so very useful and it just works.
That first issue (needing to right click to make the thing that was pasted visible) has never happened to me. When I paste stuff in it appears without messing about so I don't know what's going on there. For the second bit try going Edit->Paste as new image.
With regards to it being removed from the default installation I think it may be a mistake, it's very nice having a good image editor instaled by default but then I don't think it really matters because anyone who wants it can still install it easily.
It was a simple repair to make, but had he been turning more sharply or the tractor had something more powerful than a 30 hp ford ten engine it would have rolled and he wouldn't have been there to make the repair. Easier to fix, but not any less dangerous (the spring that broke was at the carburettor end of the cable and lifting the pedal would only make the cable flex).
A friend of mine had the return spring on a mechanical throttle break. It happened as he was going around a corner and you have no idea how scary it is to have a tractor up on two wheels. Not really arguing for or against electronic throttles here but mechanical systems can have problems too.
I believe this is already done with tomatoes at a few locations.
Everyone here is going to talk about how outrageous it is for a supermarket to be charged for playing the radio, but the fact of the matter is that they use the radio to create a pleasant environment for their customers, which makes it a tool of commerce. Songwriters are the ones who get compensated for this, and rightfully so: people are using the fruits of their labor (music) to help sell merchandise.
I would agree maybe if they were playing prerecorded music like CDs but stop and think for a minute about the radio. The station already broadcasts the music and pays the fees, and if instead of playing the radio in your shop you gave every employee/customer a portable radio they could listen to with headphones that would be entirely legal. It is absurd that there's a difference between that and just playing it for everyone to hear (unless of course the true purpose of the law is to support the manufacturers of portable radios).
As a bonus if we didn't have this stupid rule call centres could just play a national radio station while they put you on hold rather than driving you insane with utterly crap annoying “music”