He had a hard time getting his truck to pass emissions at first since the exhaust was so much cleaner than the air around the test station.
A lot of people claim this about hydrogen - but actually, because hydrogen burns at a very high temperature its combustion produces large amounts of smog-producing NOx.
Unfortunatly, conventional auto catalytic converters aren't ideal for converting this, because the exhaust lacks the reducing agents (hydrocarbons and carbon monoxide) found in gasoline exhuast.
There are ways to get around this, but it's not a simple retrofit - engine management systems need to be carefully tuned with new software algorithms.
Clearly you must have some metabolic disease, or be some non-human lifeform.
Metabolism is very well understood, and is very simple. Every calorie absorbed from food is either burned for energy or is stored - unless a disease (e.g. diabetes) causes them to be lost. The body has no mechanism to dump unneeded calories. This is precisely the reason why obesity is such a common problem today.
Sure, some energy is needed to keep body temperature up and for the idle (basal) metabolism - but again, this is an extremely closely regulated mechanism, with virtually no difference between people (in the absence of significant illness - e.g. thyroid disease).
A healthy stomach/intestine can easily absorb 15,000 calories a day without wastage - if your stomach/intestine didn't absorb all the calories in your food, you'd have hideous diarrhoea/flatulance/stomach cramps.
Shifting into neutral won't do anything in the case if everything is electronic and the shifter is just a front to some software.
Except that on every car I've seen the transmission is not completely electronic. Even brand new ones with electronic control and paddle shifts.
I've got a recent schematic to hand which illustrates the hydraulic circuit. The oil is directed to various brakes and clutches via several electronically actuated solenoid valves. However, before the oil reaches the slave cylinders, it passes through a mechanical valve connected to the shift lever.
Push the lever into neutral and no matter what the computer wants, no oil pressure is available with which to engage the transmission.
Also I'd like to say that the story poster's alarmist warnings of 5mW lasers is completely unfounded. The extremely high (relatively, anyway) divergence experienced by almost all cheapo, poorly colimated 5mW laser pointers means the beam will be at least inches wide if shone on something as far away as an airplaine at thousands of feet up.
Not just that, but the actual amount of light from a laser pointer of less than 5mW is very unlikely to cause eye injury.
There have been case reports of children attempting to demonstrate the 'pupil reflex' using a laser pointer as the stimulus. While they suffered 'after images' and were taken to a hospital for examination, there was no permanent effect.
Similar experiments have been performed on people awaiting eye removal surgery (for eye cancer). These people stared directly into the beams of low powered lasers for periods of up to 15 minutes (with their bad eye). There was no evidence of any eye damage from the laser exposure.
Some case series have found that some people who have been exposed to laser pointers had slightly reduced vision in the exposed eye - despite this, however, it is difficult to reach a firm conclusion as these people didn't have any recent eye tests before the exposure.
This is not to say that these lasers incorrectly used are not dangerous - they can easily cause highly distracting visual disturbance, which could be disastrous for an airline pilot, or even a car driver. Indeed, while planes at altitude are relatively safe - there have been a few incidents where pilots have been dazzled on the approach to landing, where they are much closer to the ground.
The real danger to vision is from incorrectly classified lasers, or higher powered lasers sold as pointers. I know at least one trader who would be prepared to sell a laser 'pointer' with guaranteed 100 mW output. There's no doubt that such a device could cause rapid permanent injury. Of course, it's illegal to sell these - but that doesn't mean that they're hard to get.
Spent nuclear fuel contains the intensely radioactive fission products, as well as less radioactive (but enormous half lives) heavy actinide elements (uranium, plutonium, americium, etc.)
The vast majority of the fission products have short or medium duration half-lives.
The actinide elements are fissile (given a fast neutron source), and can therefore be burned for energy in a suitable reactor (potential designs include the liquid sodium cooled, liquid lead cooled, gas cooled reactors and molten salt reactors).
The very few long-lived fission products (e.g. Tc99) could be added to the actinide mixture, where they could be transmuted into shorter lived isotopes by the neutron flux in the reactor.
An advanced reprocessing scheme could take spent fuel, extract only the fission products, and prepare these for disposal. The remaining highly radioactive mixture of plutonium, uranium and other elements, could be returned to the reactor for further burning.
The mixture of fission products would have short-lived radioactiviy, decaying to less than natural uranium ore within 300 years.
The impure uranium/plutonium mix would be self protecting against theft due to the intense radioactivity of the contaminants.
The law changed a few years ago. Items now have to be of 'satisfactory quality' (not 'merchantable quality'). This has not been very clearly defined, but probably means what a typical customer for that type of product would find acceptable.
The Sale of Goods Act also only applies to retail sales to end-users. It does not apply to the agreement between the manufacturer and the retailer, nor does it apply to private sales.
This means that if you a buy some software at a swap meet, or privately off ebay, and it is unusable, then you have no statutory recourse to either the seller or the manufacturer.
Well, it could by like the way doctors' hours are managed in the UK.
If there is a shortage of medical staff (e.g. due to sickness) then someone will be asked to cover their shift. During the day, this is fine (someone just has to do 2 people's jobs) as it doesn't cost anything.
However, out of hours - it's a matter of asking people to volunteer for the shift, to be done at a fixed rate of pay (non-negotiable).
What if no one wants to do the shift? The hospital has a lottery - someone's name is chosen at random, and they have to do the shift (again, non-negotiable>
Don't forget that energy can be massively multiplied with suitable reactor technology (i.e. breeders).
A fully recycled breeder reactor system could obtain 50x as much energy from the uranium.
The same could be done with thorium - except that thorium is 3-4x as abundant as uranium in coal.
The total energy resource of nuclear materials in coal, exceeds the energy content of the coal by more than an order or magnitude.
Switching off displays, or using the power control panel to switch off the display after a period of use is very sensible. It saves energy and prolongs the life of the screen.
You should also consider energy saving features for the PC as well. Modern PCs have very good standby modes - from spinning down unused hard drives, to 'low power standby mode' or 'suspend to RAM'. In suspended state the power consumption of a typical PC is about 5 W. Yet, returning to the desktop takes about 5 seconds.
These features work very well on Windows, although I don't know about Linux.
I've been very concerned about the proliferation of PC periphs, each with their own AC adaptor - the standby power of these is very significant. I have a lot of periphs, but they have an 'idle' draw of about 40W, and contribute about 10% of my entire energy bill.
Some older PSUs had an internal relay, with a switched output - although these have fallen out of favour because current safety regulations prohibit this.
I wonder if there would be a market for a power strip that could monitor the power consumption of the PC and switch the periphs on and off. Hmm. Maybe it would be easier just to connect the power strip to a USB port (power on - switch on periphs. Power off - switch off periphs).
Modern bead reactors of the type the chinese are building are VASTLY less likely to meltdown than any reactor currently running in the US. The coolant in a bead reactor actually catalyses the reaction, so without coolant, there is no reaction.
The coolant in a pebble reactor has no effect on the reaction - the helium is totally transparent. This is in contrast to a conventional PWR where the water coolant is a catalyst - boiling or loss of coolant causes collapse of the nuclear reaction.
The safety of the pebble reactors come from 3 things:
1) thermal expansion of the fuel as it heats up causes 'dilution' of the fuel and 'doppler broadening' both of which shut down the nuclear reaction when operating temperatures are exceeded.
2) Very high melting point of the fuel (>2200 C) means that massive temperature excursions of the fuel are safe
3) the very dilute fuel embedded in large volumes of graphite has a very low power to volume ratio. This coupled with a tiny reactor (with large surface area to volume ratio) means that convection of air around the outside is sufficient to cool the fuel.
So, in the event of loss of coolant - the fuel temperature will rise from it's nominal 1000C towards 1600C. As the temp rises, the heat production will fall, eventually at 1600C the heat production will equal rate of heat removal by natural air circulation and the system will stabilise.
The same passive safety principle as in point 1, is used in modern water cooled reactor designs - together with the water acting as a catalyst. This dramatically lowers the risk of meltdown accident, and improves the stability of the reactor. However, because the fuel is very concentrated and dense with very high power density, good quality cooling must be maintained at all costs - so sophisticated backup systems are still required despite improvements in stability.
The disadvantages of the pebble reactor are:
1) that the pebbles are made of flammable carbon - if the helium coolant is lost, and air gets into the reactor, it will burn with great vigour.
2) it relies on the microscopic coating of each tiny fuel grain to contain the radioactive waste. Early prototypes of this type of reactor had intractable problems with waste leaking out of the fuel and contaiminating the reactor.
3) the fuel is very bulky which can pose storage problems. Reprocessing of this fuel form to retrieve unburned uranium or reduce bulk is also unlikely to be practical.
Believe me, mission critical reliability doesn't seem to be important to most NHS hospitals.
At one hospital where I work we regularly (several times a year) have day long outages of the key health-care IT systems (i.e. the records access systems used by doctors in the ER and on the wards). Often the network outage is triggered by something which shouldn't (like a routine scheduled generator test).
At other places, the terminals on the wards, are just that - VT420 terminals. Where these have expired, they've been replaced by a multitude of PCs built by local box-builders and run a mixture of Win95, Win98, Win2k and WinXP.
Of course, if you are clerical staff - then you could be left even worse off. I know of at least one hospital department, where the clerical staff have to use old 286 PCs. They now cannot upgrade because the software they use is no longer produced and the hardware keys are not compatible with modern equipment.
The current system, or lack of consistency within it, is a disaster. Surely, any form of standardised system would work better than some of the systems out there today.
Perhaps, not on direct life-support equipment like ventilators or infusion pumps, but monitoring equipment and some diagnostic equipment.
The monitors at my hospital's cardiac care unit run on Windows NT 4. Only seen it boot up once though, and that was after a power glitch - no one thought to put a UPS on it.
Some blood analysers also run on Windows NT; the blood gas analysers I use run windows (I think it might even be win2k but I can't remember). I sometimes feel a bit twitched when I've got an irreplaceable sample in my hand, and due to difficulty in obtaining it, only have enough blood for one go.
Fortunately, on all the monitoring systems I've seen, they all have their individual private LANs with no external access. It might limit transfer of data, but at least it stops the equipment from getting 0wned by worms.
I'm very concerned about all those extra connections. The connections are the weakest point on current PSUs/motherboards; I have seen a number of PSUs or boards with melted connectors because they were either of substandard quality or not fully pushed home.
Each connector provides additional resistance in the circuit leading to voltage sags and heat build up in the connectors.
I'd be more interested if this PSU offered high efficiency and Active PFC. (Active PFC opens the way for more efficient PSU designs). Current PSUs offer an electrical efficiency of about 68% - on a high-end system, the PSU could be pumping out over 100 W of heat itself, making it even more of a space heater than the CPU - and requiring substantial fans too.
Modern industrial SMPSs can achieve electrical efficiencies which are much higher. I've seen telecoms grade 400W PSUs claim efficiency of over 95% - so the technology exists to mass produce these things today.
Also, this review made no mention of protection systems:
Any overheat protection?Or will the PSU burn under overload or if a fan fails?
Over voltage protection? Will the PSU shut off if an overvoltage condition occurs? Is there a 'fail-safe' crowbar system which can guarantee the safety of the rest of your PC (even if it has to sacrifice the PSU?)
Incredibly, the safety features listed above, are not standard on all PC PSUs - only a very few offer crowbar protection.
Nice to know these cards are so tough. I've been struggling to think of some conceivable situations which might actually cause accidental damage.
1) Trip to beach (Lots of salt and sandy bits)
2) Immersion under pressure (dropped in swimming pool)
3) Magnetic fields (accidentally taken for an MRI scan)
4) Ionizing radiation (Multiple airport X-rays)
5) Extremes of temperature (left in car in winter)
Some airlines are now planning to offer in-flight cell-phone service. However, simply offering this service, has the side effect of drastically reducing the risk of interference from the phones themselves.
Essentially, a very low-power base-station is integrated into the plane, with the antenna in the cabin. A satellite uplink connects it to ground based communications networks.
Cell phones use automatic transmission power control algorithms. As the phone and base are in such close proximity, the transmission power is set an extremely low level (typically 1% of normal). At this level, harmful interference is exceptionally unlikely.
It seems this chap's whole case is that the university should have noticed his cheating and confronted him sooner.
The timing of the disciplinary action is irrelevant. He knew that cheating was liable to get him disciplined and/or dismissed, and he even admits that. Does he seriously expect the university to check every piece of work he handed it, at the time he hands it it? Does he expect them to do the same for every student?
Surely, the more likely situation was that a few of his later pieces of work aroused suspicion. This then led to a fuller investigation to assess the rest of his work. Then once the investigation had been completed, and a clear case could be made, he was confronted by the evidence.
When I was at University, one of the student's had managed to cheat in each formal set of exams in a full 6 year medical course. She was only dismissed after the final exams, days before graduation, and after paying fees close to 100,000.
The cheating only came to light when one student who was absolutely certain he had passed a certain paper (it was his 2nd attempt and he had worked like a dog for it) was told he had failed. He was called up before the Dean a couple of days before the results were published. He asked to see his paper, and it wasn't his - somebody had switched the answer papers.
Subsequently, there was a full investigation and several other exams were scrutinised - evidence of cheating was found throughout the course. Suspicions were also raised about some informal 'prize' exams during the course, but this could never be proved as the papers were destroyed after marking.
Reprocessing is a method of recycling nuclear fuel and reducing the amount of waste that needs disposal.
A typical fuel rod may consist of 97% U238 and 3% U235 (The U-235 is the actual fuel). When the fuel is exhausted, the composition is closer to 2% U235, 96.5% U238, 1% Fission products and 0.5% actinides. There is still a substantial amount of U235 fuel left in the exhausted fuel rods, but the rods are now intensely radioactive due to the fission products. The actinides (primarily plutonium) are also radioactive, but unlike the fission products which are generally very short-lived the actinides are very long lived (tens of thousands of years).
Reprocessing aims to reduce the amount of waste by reclaiming the Uranium from the spent fuel - usually the actinides are also reclaimed, because they too are usable as fuel. In the UK, the reprocessed fuel is packaged into 'MOX' (mixed uranium/plutonium oxide) fuel for use in power generation. The other advantage of reprocessing is that the amount of the waste is greatly reduced as 99% of the spent fuel is recycled. This much smaller volume of material is supposed to be easier to dispose of.
However, there are a number of problems with reprocessing - it is expensive and difficult process. The intensely radioactive spent fuel must be dissolved in boiling concentrated acids, with the final waste product being a corrosive liquid loaded with fission products. The idea was to 'vitrify' the waste, by mixing the waste with molten glass and fusing it into solid blocks the size of oil drums. This has been done, but the vitrification plants have been plagued with problems - at Sellafield in the UK, 2 vitrification process lines were built and thought to easily cope with the throughput of the reprocessing plant. These have proved so unreliable (due to radiation damage to the equipment) that there are now there are 6 vitrification production lines and a backlog of waste that will take several years to deal with. The plant will have to keep on operating until the last of the old generation of MAGNOX reactor power stations are closed - the magnox reactors used magnesium clad fuel rods. Unlike modern stainless steel fuel rods, magnesium is not well known for its corrosion resistance, and the rods must be reprocessed as they are not safe for disposal as is.
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A lot of people claim this about hydrogen - but actually, because hydrogen burns at a very high temperature its combustion produces large amounts of smog-producing NOx.
Unfortunatly, conventional auto catalytic converters aren't ideal for converting this, because the exhaust lacks the reducing agents (hydrocarbons and carbon monoxide) found in gasoline exhuast.
There are ways to get around this, but it's not a simple retrofit - engine management systems need to be carefully tuned with new software algorithms.
Clearly you must have some metabolic disease, or be some non-human lifeform. Metabolism is very well understood, and is very simple. Every calorie absorbed from food is either burned for energy or is stored - unless a disease (e.g. diabetes) causes them to be lost. The body has no mechanism to dump unneeded calories. This is precisely the reason why obesity is such a common problem today. Sure, some energy is needed to keep body temperature up and for the idle (basal) metabolism - but again, this is an extremely closely regulated mechanism, with virtually no difference between people (in the absence of significant illness - e.g. thyroid disease). A healthy stomach/intestine can easily absorb 15,000 calories a day without wastage - if your stomach/intestine didn't absorb all the calories in your food, you'd have hideous diarrhoea/flatulance/stomach cramps.
Except that on every car I've seen the transmission is not completely electronic. Even brand new ones with electronic control and paddle shifts.
I've got a recent schematic to hand which illustrates the hydraulic circuit. The oil is directed to various brakes and clutches via several electronically actuated solenoid valves. However, before the oil reaches the slave cylinders, it passes through a mechanical valve connected to the shift lever.
Push the lever into neutral and no matter what the computer wants, no oil pressure is available with which to engage the transmission.
Not just that, but the actual amount of light from a laser pointer of less than 5mW is very unlikely to cause eye injury.
There have been case reports of children attempting to demonstrate the 'pupil reflex' using a laser pointer as the stimulus. While they suffered 'after images' and were taken to a hospital for examination, there was no permanent effect.
Similar experiments have been performed on people awaiting eye removal surgery (for eye cancer). These people stared directly into the beams of low powered lasers for periods of up to 15 minutes (with their bad eye). There was no evidence of any eye damage from the laser exposure.
Some case series have found that some people who have been exposed to laser pointers had slightly reduced vision in the exposed eye - despite this, however, it is difficult to reach a firm conclusion as these people didn't have any recent eye tests before the exposure.
This is not to say that these lasers incorrectly used are not dangerous - they can easily cause highly distracting visual disturbance, which could be disastrous for an airline pilot, or even a car driver. Indeed, while planes at altitude are relatively safe - there have been a few incidents where pilots have been dazzled on the approach to landing, where they are much closer to the ground.
The real danger to vision is from incorrectly classified lasers, or higher powered lasers sold as pointers. I know at least one trader who would be prepared to sell a laser 'pointer' with guaranteed 100 mW output. There's no doubt that such a device could cause rapid permanent injury. Of course, it's illegal to sell these - but that doesn't mean that they're hard to get.
Spent nuclear fuel contains the intensely radioactive fission products, as well as less radioactive (but enormous half lives) heavy actinide elements (uranium, plutonium, americium, etc.)
The vast majority of the fission products have short or medium duration half-lives.
The actinide elements are fissile (given a fast neutron source), and can therefore be burned for energy in a suitable reactor (potential designs include the liquid sodium cooled, liquid lead cooled, gas cooled reactors and molten salt reactors).
The very few long-lived fission products (e.g. Tc99) could be added to the actinide mixture, where they could be transmuted into shorter lived isotopes by the neutron flux in the reactor.
An advanced reprocessing scheme could take spent fuel, extract only the fission products, and prepare these for disposal. The remaining highly radioactive mixture of plutonium, uranium and other elements, could be returned to the reactor for further burning.
The mixture of fission products would have short-lived radioactiviy, decaying to less than natural uranium ore within 300 years.
The impure uranium/plutonium mix would be self protecting against theft due to the intense radioactivity of the contaminants.
The Sale of Goods Act also only applies to retail sales to end-users. It does not apply to the agreement between the manufacturer and the retailer, nor does it apply to private sales.
This means that if you a buy some software at a swap meet, or privately off ebay, and it is unusable, then you have no statutory recourse to either the seller or the manufacturer.
If there is a shortage of medical staff (e.g. due to sickness) then someone will be asked to cover their shift. During the day, this is fine (someone just has to do 2 people's jobs) as it doesn't cost anything.
However, out of hours - it's a matter of asking people to volunteer for the shift, to be done at a fixed rate of pay (non-negotiable).
What if no one wants to do the shift? The hospital has a lottery - someone's name is chosen at random, and they have to do the shift (again, non-negotiable>
Don't forget that energy can be massively multiplied with suitable reactor technology (i.e. breeders). A fully recycled breeder reactor system could obtain 50x as much energy from the uranium. The same could be done with thorium - except that thorium is 3-4x as abundant as uranium in coal. The total energy resource of nuclear materials in coal, exceeds the energy content of the coal by more than an order or magnitude.
You should also consider energy saving features for the PC as well. Modern PCs have very good standby modes - from spinning down unused hard drives, to 'low power standby mode' or 'suspend to RAM'. In suspended state the power consumption of a typical PC is about 5 W. Yet, returning to the desktop takes about 5 seconds.
These features work very well on Windows, although I don't know about Linux. I've been very concerned about the proliferation of PC periphs, each with their own AC adaptor - the standby power of these is very significant. I have a lot of periphs, but they have an 'idle' draw of about 40W, and contribute about 10% of my entire energy bill.
Some older PSUs had an internal relay, with a switched output - although these have fallen out of favour because current safety regulations prohibit this. I wonder if there would be a market for a power strip that could monitor the power consumption of the PC and switch the periphs on and off. Hmm. Maybe it would be easier just to connect the power strip to a USB port (power on - switch on periphs. Power off - switch off periphs).
The coolant in a pebble reactor has no effect on the reaction - the helium is totally transparent. This is in contrast to a conventional PWR where the water coolant is a catalyst - boiling or loss of coolant causes collapse of the nuclear reaction.
The safety of the pebble reactors come from 3 things:
1) thermal expansion of the fuel as it heats up causes 'dilution' of the fuel and 'doppler broadening' both of which shut down the nuclear reaction when operating temperatures are exceeded.
2) Very high melting point of the fuel (>2200 C) means that massive temperature excursions of the fuel are safe
3) the very dilute fuel embedded in large volumes of graphite has a very low power to volume ratio. This coupled with a tiny reactor (with large surface area to volume ratio) means that convection of air around the outside is sufficient to cool the fuel.
So, in the event of loss of coolant - the fuel temperature will rise from it's nominal 1000C towards 1600C. As the temp rises, the heat production will fall, eventually at 1600C the heat production will equal rate of heat removal by natural air circulation and the system will stabilise.
The same passive safety principle as in point 1, is used in modern water cooled reactor designs - together with the water acting as a catalyst. This dramatically lowers the risk of meltdown accident, and improves the stability of the reactor. However, because the fuel is very concentrated and dense with very high power density, good quality cooling must be maintained at all costs - so sophisticated backup systems are still required despite improvements in stability.
The disadvantages of the pebble reactor are: 1) that the pebbles are made of flammable carbon - if the helium coolant is lost, and air gets into the reactor, it will burn with great vigour. 2) it relies on the microscopic coating of each tiny fuel grain to contain the radioactive waste. Early prototypes of this type of reactor had intractable problems with waste leaking out of the fuel and contaiminating the reactor. 3) the fuel is very bulky which can pose storage problems. Reprocessing of this fuel form to retrieve unburned uranium or reduce bulk is also unlikely to be practical.
Believe me, mission critical reliability doesn't seem to be important to most NHS hospitals. At one hospital where I work we regularly (several times a year) have day long outages of the key health-care IT systems (i.e. the records access systems used by doctors in the ER and on the wards). Often the network outage is triggered by something which shouldn't (like a routine scheduled generator test). At other places, the terminals on the wards, are just that - VT420 terminals. Where these have expired, they've been replaced by a multitude of PCs built by local box-builders and run a mixture of Win95, Win98, Win2k and WinXP. Of course, if you are clerical staff - then you could be left even worse off. I know of at least one hospital department, where the clerical staff have to use old 286 PCs. They now cannot upgrade because the software they use is no longer produced and the hardware keys are not compatible with modern equipment. The current system, or lack of consistency within it, is a disaster. Surely, any form of standardised system would work better than some of the systems out there today.
The monitors at my hospital's cardiac care unit run on Windows NT 4. Only seen it boot up once though, and that was after a power glitch - no one thought to put a UPS on it.
Some blood analysers also run on Windows NT; the blood gas analysers I use run windows (I think it might even be win2k but I can't remember). I sometimes feel a bit twitched when I've got an irreplaceable sample in my hand, and due to difficulty in obtaining it, only have enough blood for one go.
Fortunately, on all the monitoring systems I've seen, they all have their individual private LANs with no external access. It might limit transfer of data, but at least it stops the equipment from getting 0wned by worms.
Each connector provides additional resistance in the circuit leading to voltage sags and heat build up in the connectors.
I'd be more interested if this PSU offered high efficiency and Active PFC. (Active PFC opens the way for more efficient PSU designs). Current PSUs offer an electrical efficiency of about 68% - on a high-end system, the PSU could be pumping out over 100 W of heat itself, making it even more of a space heater than the CPU - and requiring substantial fans too.
Modern industrial SMPSs can achieve electrical efficiencies which are much higher. I've seen telecoms grade 400W PSUs claim efficiency of over 95% - so the technology exists to mass produce these things today.
Also, this review made no mention of protection systems:
Incredibly, the safety features listed above, are not standard on all PC PSUs - only a very few offer crowbar protection.
Nice to know these cards are so tough. I've been struggling to think of some conceivable situations which might actually cause accidental damage. 1) Trip to beach (Lots of salt and sandy bits) 2) Immersion under pressure (dropped in swimming pool) 3) Magnetic fields (accidentally taken for an MRI scan) 4) Ionizing radiation (Multiple airport X-rays) 5) Extremes of temperature (left in car in winter)
Some airlines are now planning to offer in-flight cell-phone service. However, simply offering this service, has the side effect of drastically reducing the risk of interference from the phones themselves.
Essentially, a very low-power base-station is integrated into the plane, with the antenna in the cabin. A satellite uplink connects it to ground based communications networks.
Cell phones use automatic transmission power control algorithms. As the phone and base are in such close proximity, the transmission power is set an extremely low level (typically 1% of normal). At this level, harmful interference is exceptionally unlikely.
It seems this chap's whole case is that the university should have noticed his cheating and confronted him sooner.
The timing of the disciplinary action is irrelevant. He knew that cheating was liable to get him disciplined and/or dismissed, and he even admits that. Does he seriously expect the university to check every piece of work he handed it, at the time he hands it it? Does he expect them to do the same for every student?
Surely, the more likely situation was that a few of his later pieces of work aroused suspicion. This then led to a fuller investigation to assess the rest of his work. Then once the investigation had been completed, and a clear case could be made, he was confronted by the evidence.
When I was at University, one of the student's had managed to cheat in each formal set of exams in a full 6 year medical course. She was only dismissed after the final exams, days before graduation, and after paying fees close to 100,000.
The cheating only came to light when one student who was absolutely certain he had passed a certain paper (it was his 2nd attempt and he had worked like a dog for it) was told he had failed. He was called up before the Dean a couple of days before the results were published. He asked to see his paper, and it wasn't his - somebody had switched the answer papers.
Subsequently, there was a full investigation and several other exams were scrutinised - evidence of cheating was found throughout the course. Suspicions were also raised about some informal 'prize' exams during the course, but this could never be proved as the papers were destroyed after marking.
Reprocessing is a method of recycling nuclear fuel and reducing the amount of waste that needs disposal.
A typical fuel rod may consist of 97% U238 and 3% U235 (The U-235 is the actual fuel). When the fuel is exhausted, the composition is closer to 2% U235, 96.5% U238, 1% Fission products and 0.5% actinides. There is still a substantial amount of U235 fuel left in the exhausted fuel rods, but the rods are now intensely radioactive due to the fission products. The actinides (primarily plutonium) are also radioactive, but unlike the fission products which are generally very short-lived the actinides are very long lived (tens of thousands of years).
Reprocessing aims to reduce the amount of waste by reclaiming the Uranium from the spent fuel - usually the actinides are also reclaimed, because they too are usable as fuel. In the UK, the reprocessed fuel is packaged into 'MOX' (mixed uranium/plutonium oxide) fuel for use in power generation. The other advantage of reprocessing is that the amount of the waste is greatly reduced as 99% of the spent fuel is recycled. This much smaller volume of material is supposed to be easier to dispose of.
However, there are a number of problems with reprocessing - it is expensive and difficult process. The intensely radioactive spent fuel must be dissolved in boiling concentrated acids, with the final waste product being a corrosive liquid loaded with fission products. The idea was to 'vitrify' the waste, by mixing the waste with molten glass and fusing it into solid blocks the size of oil drums. This has been done, but the vitrification plants have been plagued with problems - at Sellafield in the UK, 2 vitrification process lines were built and thought to easily cope with the throughput of the reprocessing plant. These have proved so unreliable (due to radiation damage to the equipment) that there are now there are 6 vitrification production lines and a backlog of waste that will take several years to deal with. The plant will have to keep on operating until the last of the old generation of MAGNOX reactor power stations are closed - the magnox reactors used magnesium clad fuel rods. Unlike modern stainless steel fuel rods, magnesium is not well known for its corrosion resistance, and the rods must be reprocessed as they are not safe for disposal as is.