You cannot sense radiation until it is too late. Therefore, give the patient a dosimeter (film badge or something of like functionality) to confirm exposure. To me this should be basic radiation safety.
This is easier said than done. A CT scan uses collimated fans of radiation swept around the patient. A film badge would intercept only some of that radiation. Sure, you could figure out some sort of correction to extrapolate total dose -- but that's going to be far more error-prone than just looking at the system display, where the actual dose was clearly visible even before the scan started.
You're making a big assumption that they haven't. While HCI doesn't have certification requirements like traditional engineering disciplines -- although there are perennial efforts to initiate such requirements -- most manufacturers of life-critical systems have finally recognized the importance of usability, and employ HCI professionals.
(Disclaimer: I suppose I count as an "HCI professional", but I made the decision even before I entered grad school that I'd never take a position doing life-critical designs. I don't have the mental discipline required.)
Well, you prompted me to go back and find out where I'd seen it first. It was actually "scratch monkey", and it was from RISKS Digest, Sept. 1986.
I thought about explicitly crediting the Fark poster and thread, but this isn't a refereed publication. I don't plan on copypasta-ing my own posts from there, either, although I expect I may repeat some of the material here.
I think doctors, machine designers, and everyone else involved are aware of the increased radiation associated with CT scans. But if you've got someone presenting with stroke symptoms, you're balancing "additional 1 in 10,000 lifetime risk of cancer" against "irreversible brain damage increasing in severity with each passing minute". If I'm ever in that situation, I'd tell them "cook me as hard and fast as you like, and I'll deal with the side effects at my leisure."
Maybe next time they will test the damn thing before subjecting patients to it? It's a built in part of my job that I test/confirm a change after I make a change.. because often there's a likely hood of something unexpected or improperly explained that can cause an issue.
So, what you're saying is, "Always mount a scratch human."
"Hobbyists are taking their own tools and making them better, in the best tradition of American innovation"? I think you misspelled "Pirates and cyber-terrorists are stealing money from TI's hardworking engineers at virtual gunpoint."
These brown sites will by nature of them be farther way from existing infrastructure resulting in higher costs to send both materials and labor to the location.
Actually, there are quite a lot of urban sites as well. In fact, I drove past one just last week. Remember, too, that infrastructure spreads to follow and/or lead suburban sprawl. Yesterday's isolated dumping ground is today's fashionable gated community.
Building on top of a brownfield might do little to stop its contents from percolating into groundwater. (Actually, it might do something at that, simply by diverting rain that would otherwise fall onto and into it.)
I'm all for putting otherwise-unusable land to good use, but we'd need to have legal structures to protect everyone involved, so (for example) the company building the energy installation isn't suddenly on the hook for everything lurking under it.
You should read a little more. When you're done with that, you'll understand why high vs. low Tc really doesn't make much difference. Also, tell us more about the ships you'll use to carry these 100-mile-circumference loops to their destinations.
Alas, as others have pointed out upthread, the high-temp superconductors don't work well for magnets. All superconducting materials lose their superconductivity at a certain magnetic field-strength threshold; for high-Tc materials, that threshold is much lower than it is for "conventional" superconductors.
Even if that weren't an issue, the ceramic materials are generally too brittle to stand up to the mechanical forces inside a high-field magnet coil.
Our lab has experimented with high-Tc superconducting probes for MRI. Even though they're high-Tc, we still end up cooling them to the liquid-helium range.
What is "the upper part of a 9212/2212C and the lower part of a 1223?"
9212/2212C and 1223 are structure names. Would you like an introductory crystallography text with your summary next time? It would, after all, save you the onerous effort of following the article link.
And I don't believe there's an element known as Oy.
O-sub-y, indicating an indefinite ratio of oxygen.
Why don't you just say what you really mean: "Waaahhh! Our laws of physics SUCK! I don't believe in them."
Actually, I'm probably confusing you with another poster who spams about his free-energy fantasies. If you're just talking about beanstalks and solar sails, well, maybe, but I think "fuel" and "reaction mass" are going to be the central part of our intra-system arsenal for quite a long time.
These have high energy density (watt-hours over the life of the device per kg), but extremely low power density (watts per kg). They could be useful for apps where you don't ever want to change a battery, but they're useless for anything but the lowest-power apps. They won't run your cell phone, or your car, or even your iPod.
If I could get my hands on say an ounce of Pu 238 I could build a RTG that would power my home, all my vehicles, and enable me to quit my job and live of the check my local electricity provider would have to pay me for the excess power I would generate. It would generate full power for ~ 87 years and not only wold I be using the greenest power available I would be providing a community service of disposing of a radioactive material.
One ounce of Pu-238 generates around 16 watts of thermal power. If you can power your home, all your vehicles, and so forth off less than that -- remember, typical RTG efficiencies would yield about 1 watt of electricity, and you promised to sell excess power back to the grid -- you need to sign off Slashdot right now and go start clearing some shelf space for your Nobels. First, though, you should put out a one-square-foot black panel. This will absorb an average of 16 watts of continuous thermal power from sunlight, letting you bootstrap your world-changing energy-efficient technologies while you wait for that nuclear permit.
Firewire 800 can transfer 100Megabytes per second. So a disk with 2^64 bytes will take approximately 5,000 years to fill by transferring data continuously.
Golly, how long would it take to transfer it over a 300-baud modem? 'Cause, you know, 30 years ago, that was the going rate. Or maybe you could compare it to the 12.5 KB/sec transfer rate of a 1979 single-sided single-density floppy.
Clearly we need something faster. A 64 bit data bus that can do writes at 1 Gigahertz can fill the disk in a mere 70 years. That still seems like a long time to me.
And my 1979 8-bit data bus that could do writes at 0.5 MHz could... well, you get the picture. Assuming that a high-performance 2039 system would be sending all its information through a single-bus bottleneck is even sillier than assuming that a high-performance 2009 system would have a single core, single-stage pipelines, or single-bank memory.
If you've got (in 2039) 2^64 bytes of storage, I'm guessing that you'll have at least 2^32 proxels (processor elements), meaning the amount of storage per core might actually be smaller than what we see today.
There really is no point in going above 64 bit. We just can't use it all. There probably aren't 2^64 bytes in all human knowledge.
And there'll never be a market for more than five or so digital computers. Funny thing about bytes -- we keep making more of them, and there's always someone who actually wants to go back and retrieve them at some point.
Interesting example: a particular human genome contains around 3 billion base pairs, which amounts to somewhat less than a gigabyte (2^30) of information. There are somewhere over 6 billion people in the world, a bit more than 2^32. Storing all the base-pairs for all the people currently alive (stupidly, without compression) would take around 2^62 bytes. Do you really think there's no use in being able to store and process a corpus of information that large?
Having a memory — RAM or disk — above 2^64, however, is not achievable in even in theory... 2^64 is only 100 times less, for example, than the estimated number of sand-grains on Earth
So? There are more efficient encodings than one byte per sand-grain, you know.
As it turns out, 2^64 is much smaller than Avogadro's Number, the number of molecules in a mole of a chemical compound. If you could find a way to encode information in a 3D hunk of silicon, such that you needed slightly more than 1000 atoms to store each byte, 2^64 bytes of storage would amount to a bit less than one ounce of bulk silicon, occupying less than one cubic inch.
I FULLY expect to see secondary storage approaching this density within the next few decades, and I fully expect that there will be good reasons to support it in a flat address space.
c mol / LoC m = (3x10^9 m/s) mol / (10 TB) m = 0.00003 mol / byte s. I'm at a loss for how to interpret this dimensional measure. Maybe it has something to do with the number of monkeys needed to type the works of Shakespeare in a specified amount of time.
Slashdot Mirror
You cannot sense radiation until it is too late. Therefore, give the patient a dosimeter (film badge or something of like functionality) to confirm exposure. To me this should be basic radiation safety.
This is easier said than done. A CT scan uses collimated fans of radiation swept around the patient. A film badge would intercept only some of that radiation. Sure, you could figure out some sort of correction to extrapolate total dose -- but that's going to be far more error-prone than just looking at the system display, where the actual dose was clearly visible even before the scan started.
You're making a big assumption that they haven't. While HCI doesn't have certification requirements like traditional engineering disciplines -- although there are perennial efforts to initiate such requirements -- most manufacturers of life-critical systems have finally recognized the importance of usability, and employ HCI professionals.
(Disclaimer: I suppose I count as an "HCI professional", but I made the decision even before I entered grad school that I'd never take a position doing life-critical designs. I don't have the mental discipline required.)
Well, you prompted me to go back and find out where I'd seen it first. It was actually "scratch monkey", and it was from RISKS Digest, Sept. 1986.
I thought about explicitly crediting the Fark poster and thread, but this isn't a refereed publication. I don't plan on copypasta-ing my own posts from there, either, although I expect I may repeat some of the material here.
I think doctors, machine designers, and everyone else involved are aware of the increased radiation associated with CT scans. But if you've got someone presenting with stroke symptoms, you're balancing "additional 1 in 10,000 lifetime risk of cancer" against "irreversible brain damage increasing in severity with each passing minute". If I'm ever in that situation, I'd tell them "cook me as hard and fast as you like, and I'll deal with the side effects at my leisure."
Maybe next time they will test the damn thing before subjecting patients to it? It's a built in part of my job that I test/confirm a change after I make a change.. because often there's a likely hood of something unexpected or improperly explained that can cause an issue.
So, what you're saying is, "Always mount a scratch human."
"Hobbyists are taking their own tools and making them better, in the best tradition of American innovation"? I think you misspelled "Pirates and cyber-terrorists are stealing money from TI's hardworking engineers at virtual gunpoint."
[citation provided]
I got a particular kick out of the phrase "otherwise distinguished physicists" in the summary.
These brown sites will by nature of them be farther way from existing infrastructure resulting in higher costs to send both materials and labor to the location.
Actually, there are quite a lot of urban sites as well. In fact, I drove past one just last week. Remember, too, that infrastructure spreads to follow and/or lead suburban sprawl. Yesterday's isolated dumping ground is today's fashionable gated community.
Building on top of a brownfield might do little to stop its contents from percolating into groundwater. (Actually, it might do something at that, simply by diverting rain that would otherwise fall onto and into it.)
I'm all for putting otherwise-unusable land to good use, but we'd need to have legal structures to protect everyone involved, so (for example) the company building the energy installation isn't suddenly on the hook for everything lurking under it.
Found a new cause, have we, Serdar?
Seems like it could make a heck of a foundation for a solar concentrator mirror array...
You should read a little more. When you're done with that, you'll understand why high vs. low Tc really doesn't make much difference. Also, tell us more about the ships you'll use to carry these 100-mile-circumference loops to their destinations.
He could just as well be hosted on rasputin.de (funny fake homepages).
OMG Germlish! I enjoyed that so much that I could almost forgive you for inducing another seizure.
Alas, there's a big gap between knowing enough to snipe at an AC and knowing enough to evaluate the claim itself. Sorry...
Alas, as others have pointed out upthread, the high-temp superconductors don't work well for magnets. All superconducting materials lose their superconductivity at a certain magnetic field-strength threshold; for high-Tc materials, that threshold is much lower than it is for "conventional" superconductors.
Even if that weren't an issue, the ceramic materials are generally too brittle to stand up to the mechanical forces inside a high-field magnet coil.
Our lab has experimented with high-Tc superconducting probes for MRI. Even though they're high-Tc, we still end up cooling them to the liquid-helium range.
What is "the upper part of a 9212/2212C and the lower part of a 1223?"
9212/2212C and 1223 are structure names. Would you like an introductory crystallography text with your summary next time? It would, after all, save you the onerous effort of following the article link.
And I don't believe there's an element known as Oy.
O-sub-y, indicating an indefinite ratio of oxygen.
Whoops, missed your post downthread. Please ignore my second paragraph.
Why don't you just say what you really mean: "Waaahhh! Our laws of physics SUCK! I don't believe in them."
Actually, I'm probably confusing you with another poster who spams about his free-energy fantasies. If you're just talking about beanstalks and solar sails, well, maybe, but I think "fuel" and "reaction mass" are going to be the central part of our intra-system arsenal for quite a long time.
...is that it's slower than this technique, and by a mere .14 bps.
Forrest M. Mims III built one in 1975! From Radio Shack catalog parts!
(But probably not in a cave.)
These have high energy density (watt-hours over the life of the device per kg), but extremely low power density (watts per kg). They could be useful for apps where you don't ever want to change a battery, but they're useless for anything but the lowest-power apps. They won't run your cell phone, or your car, or even your iPod.
If I could get my hands on say an ounce of Pu 238 I could build a RTG that would power my home, all my vehicles, and enable me to quit my job and live of the check my local electricity provider would have to pay me for the excess power I would generate. It would generate full power for ~ 87 years and not only wold I be using the greenest power available I would be providing a community service of disposing of a radioactive material.
One ounce of Pu-238 generates around 16 watts of thermal power. If you can power your home, all your vehicles, and so forth off less than that -- remember, typical RTG efficiencies would yield about 1 watt of electricity, and you promised to sell excess power back to the grid -- you need to sign off Slashdot right now and go start clearing some shelf space for your Nobels. First, though, you should put out a one-square-foot black panel. This will absorb an average of 16 watts of continuous thermal power from sunlight, letting you bootstrap your world-changing energy-efficient technologies while you wait for that nuclear permit.
Firewire 800 can transfer 100Megabytes per second. So a disk with 2^64 bytes will take approximately 5,000 years to fill by transferring data continuously.
Golly, how long would it take to transfer it over a 300-baud modem? 'Cause, you know, 30 years ago, that was the going rate. Or maybe you could compare it to the 12.5 KB/sec transfer rate of a 1979 single-sided single-density floppy.
Clearly we need something faster. A 64 bit data bus that can do writes at 1 Gigahertz can fill the disk in a mere 70 years. That still seems like a long time to me.
And my 1979 8-bit data bus that could do writes at 0.5 MHz could... well, you get the picture. Assuming that a high-performance 2039 system would be sending all its information through a single-bus bottleneck is even sillier than assuming that a high-performance 2009 system would have a single core, single-stage pipelines, or single-bank memory.
If you've got (in 2039) 2^64 bytes of storage, I'm guessing that you'll have at least 2^32 proxels (processor elements), meaning the amount of storage per core might actually be smaller than what we see today.
There really is no point in going above 64 bit. We just can't use it all. There probably aren't 2^64 bytes in all human knowledge.
And there'll never be a market for more than five or so digital computers. Funny thing about bytes -- we keep making more of them, and there's always someone who actually wants to go back and retrieve them at some point.
Interesting example: a particular human genome contains around 3 billion base pairs, which amounts to somewhat less than a gigabyte (2^30) of information. There are somewhere over 6 billion people in the world, a bit more than 2^32. Storing all the base-pairs for all the people currently alive (stupidly, without compression) would take around 2^62 bytes. Do you really think there's no use in being able to store and process a corpus of information that large?
Having a memory — RAM or disk — above 2^64, however, is not achievable in even in theory... 2^64 is only 100 times less, for example, than the estimated number of sand-grains on Earth
So? There are more efficient encodings than one byte per sand-grain, you know.
As it turns out, 2^64 is much smaller than Avogadro's Number, the number of molecules in a mole of a chemical compound. If you could find a way to encode information in a 3D hunk of silicon, such that you needed slightly more than 1000 atoms to store each byte, 2^64 bytes of storage would amount to a bit less than one ounce of bulk silicon, occupying less than one cubic inch.
I FULLY expect to see secondary storage approaching this density within the next few decades, and I fully expect that there will be good reasons to support it in a flat address space.
c mol / LoC m = (3x10^9 m/s) mol / (10 TB) m = 0.00003 mol / byte s. I'm at a loss for how to interpret this dimensional measure. Maybe it has something to do with the number of monkeys needed to type the works of Shakespeare in a specified amount of time.