Quite the contrary: the high temperature heat collected by CSP systems (Concentrating Solar Power) can be stored for later use in cheap media such as gravel. Storage for upkeep of electricity production during the night is economically feasible, storage for bridging longer periods is not. It is cheaper to have a fuel-fired auxiliary boiler in the system for the occasional instances when the stored heat is exhausted.
Solar cells and wind turbines rely on backup by conventional power plants because they cannot produce electricity on demand. Concentrating Solar Power (i.e. solar thermal electricity generation) differs fundamentally because the collected heat can be stored relatively cheaply and used to sustain production during the night. Occasionally the storage will be insufficient, in those cases a simple fossil fueled boiler can temporarily take care of the steam supply for the turbine.
Large scale deployment of Concentrating Solar Power (i.e. solar thermal electricity generation) could bring the cost down to less than 6$c/kWh within 20 years. High Voltage DC technology for economical transportation of electricity over very large distances is already available. It's been said before but bears repeating that a small part of the worlds deserts can capture enough solar power to satisfy the worlds total energy demand for transport, heating as well as electricity.
There is every reason to pump at least as much taxpayers money into the deployment of CSP as is now the case for other renewables. The biggest hurdle for governments and investors is the fact that in order to be economical, CSP plants must be big (in the order of 100 MW) and situated in deserts, which for most countries means outside their own borders and therefore requires close international cooperation. Ignorance of technology in general and CSP in particular of the media, politicians and the public at large is the other big problem. Most of them still think there is only one kind of solar power and in several years of lobbying for CSP I have found that you have to explain the basics two, three or even more times before the message begins to percolate through to the brain.
There is plenty of solid information about CSP all over the www. If you can read Dutch, take a look at our website: www.gezen.nl
You forget the five Solar Thermal plants at Kramer Junction which together produce 165 MW. SEGS III - VII, as they are called, have been in commercial operation for around twenty years now. These are definitely utility scale plants, not demonstration plants.
Concentrating Solar Thermal Power plants have been in successful operation for decades in California. Note how the article avoids any mention of them, instead comparing Concentrating Solar PV with non-concentrating Si-PV. Note also how proponents of solar PV (and of wind turbines) always "forget" to mention the biggest drawback, which is the fact that they only produce electricity when the sun shines or the wind blows. CSTP differs fundamentally in that the energy is collected in the form of high temperature heat, which can be temporarily stored by various methods. This means that the electricity production can be fully controlled and that production can be sustained 24 hours a day.
The largest single CSTP plant has been turning out 80MW for almost 20 years now. Low fossil fuel prices made further development temporarily unattractive but the rate of development and deployment is picking up again for obvious reasons. Once the learning curve kicks in the price of CSTP will gradually go from the current 12 c/kWh to something like 5 c/kWh. Include the cost of all the back-up power needed for intermittent solar-PV and wind power and it is obvious that they will never be able to compete with CSTP in time to solve the upcoming energy crisis.
I admit not having read the linked article. I have now and didn't see anything new. The statement that excessive wind power was probably a primary factor was made the next day by Marcel Bial, head of the UCTE (transmission coordinators), however the detailed analysis is still ongoing and the final report will be issued in a fortnight. For me this was an opportunity to draw attention to the widespread misconception that all forms of solar electricity production are equal in the sense that they only work when the sun shines. Solar Thermal is different because it collects the suns heat and utilizes that to power a heat engine such as a steam turbine. The point is that (high temperature) heat can be stored economically for a reasonable period whereas electricity from e.g. PV cells and wind turbines cannot. If you are curious about CSP I suggest visiting www.solarpaces.org as a good starting point.
Nope. The primary cause was overload of the network due to excess production of wind energy. In Germany the wind turbine operators are allowed to pump all the electrcity into the net that they can produce and the utilities are compelled by law to deal with it. Overloads will become more frequent as more and bigger turbines are brought online. The latest multi-megawatt turbines can produce electricity relatively economically but they are not so economical if one includes the hidden costs of compensating for the enormous variations in power output. The only viable long-term large-scale solution is some form of solar power. Concentrating Solar Thermal Power is the most promising option in my book because we already know that it works, we know that it can be cheap in the long run, that it can guarantee 24/7 production by including heat storage and that there is more than enough of it on tap. Wind and PV solar are simply too fickle to rely on. Anything a nuclear boiler can do, the sun can do better. Nuclear reactors are limited to about 1000 degrees Celsius, solar boilers can go far beyond that. They have enormous potential for the production of e.g. fuels for transport purposes such as hydrogen or hydrocarbons from atmospheric carbon dioxide.
Quotation from the article: "Wind and solar power have their place, but because they are intermittent and unpredictable they simply can't replace big baseload plants such as coal, nuclear and hydroelectric." Apparently Moore has never heard of Concentrating Solar Power. This is a proven technology which, combined with heat storage, can replace all the baseload plants in the world. Although the heat storage part is still in a more or less experimental phase, there is no doubt that it can be done. The best and most economical place to build CSP power stations happens to be in hot arid areas, where nobody wants to live anyway. Instead of being detrimental to the environment, the shade of the collector fields will probably be beneficial to the local environment. The current state of High Voltage Direct Current technology is such that one cable can transport over 6 gigawatts of electricity over thousands of kilometers. This is already being done in China.
Moore and the collective Slashdot crowd should be ashamed of themselves for completely ignoring this option.
A detailed plan for generating electricity in the Sahara already exists. The technology is called Concentrating Solar Power or CSP and has already proved itself on a large scale in the Mojave Desert. The details have been worked out by TREC, the Trans-Mediterranean Energy Cooperation. See http://www.trec-eumena.org/
The results of the EU ECOSTAR CSP program have just been released at a workshop held last thursday in Brussels. The 140-page report can be downloaded from ftp://ftp.dlr.de/ecostar. CSP power stations occupying an area the size of France in the Sahara, using available technology, can produce the current total energy consumption of the whole world.
Nowhere does the originating paper in Nature mention the prospects of the device as a photovoltaic conversion system. However one of the figures shows that when it is irradiated with 70 milliwatts of infrared light, it can deliver 130 nanoamps at 180 millivolts. The product of the latter two values is 23.4 nanowatts. Hence the energy conversion efficiency is 0.00003%, or roughly one millionth of the conversion efficiency of a Concentrating Solar Power electricity generating plant such as the one at Kramer Junction in CA. A CSP system also has the ability to store heat collected during the day so it can continue production during the night. No PV system can ever compete with that.
The parent makes a few good points. However the design of the Prius powertrain is so unorthodox that almost everyone misses the really cunning part, which is that it actually has two transmissions working in parallel. The power from the IC engine (when it's running) is partitioned among them by a differential drive. One part goes to the infinitely variable electrical CVT (= generator + motor) and the other part goes straight to the wheels.The transmission ratio of this part is essentially that of top gear.
When cruising all the power is transmitted by the direct drive and none by the electric motor. That only provides the additional torque when more torque is required than top gear can provide, therefore the additional electrical losses are only incurred when you put your foot down.
The second point that is usually missed is the fact that the Prius sports an Atkinson cycle engine, which is more efficient at part load than the usual Otto cycle engine. The Atkinson cycle goes a long way towards making up the difference in efficiency between the Otto and the Diesel cycle at part load.
As usual, the collective Slashdot memory is short. The German company IAV pushed the envelope of steam power for wheeled vehicles way beyond Bowshers design and published their results in 2001. Check it out at http://www.iavinc.com/alternativedrives.html
The company is Radiation Shield Technologies and Demron is name of the product. It is up to them to point others to credible independent proof of their claims if there is any. As you can see here: http://www.vanderbilt.edu/radsafe/0211/msg00186.ht ml I'm not the only skeptical pro. IAAP (=physicist); sorry about the typo in my previous post.
As others have already pointed out, the stuff you are referring to is Demron, manufactured by RST. When I first heard of it a year or so ago I found their claim regarding its extraordinary X-ray absorbing capability very hard to believe in the light of well-established physical model of the absorption of EM radiation by matter. The report published by Lawrence Livermore Lab. was funded by RST and the author did not respond to my request for a scientific explanation.
Until the results have been independently verified and published in a peer-reviewed journal, or else verified by myself, I will continue to have grave doubts concerning their claim. (IIAP and part of my job is monitoring the radiation safety of X-ray emitting apparatus.)
Actually it's not beta radiation (= electrons emitted by nuclei). The electrons emitted by the cathode and accelerated to 30+ kV do not penetrate the glass. They excite the screen to produce visible light and the undesireable byproduct is 30+ kV X-rays which have far greater penetrating power, hence the X-ray absorbing lead in the glass.
Thanks for the reference. Note that Meyer's design involves measuring the air pressure in front of the cone with a microphone, and that on a reflex system where lots of sound is bypassing said microphone. This is a far cry from Philips' KISS design philosophy and cannot be classified as motional feedback. No wonder Meyer says "this is a very complex problem to solve, and one that has defeated all previous attempts"! However MFB does not constitute a "previous attempt" to solve the problem he set himself.
I am aware of the discussion about the perceived quality of sound reproduction of Philips' MFB range, but chose not to bring it up as it would take us off topic. Actually the closed loop motion control only operates up to 500 Hz and the 4" driver carries on passively up to the crossover point at 1500 Hz (also passive) where the tweeter takes over. In other words the MF and HF department is uninteresting. However the LF and especially the VLF part remains unique and I feel that the fundamental principle (i.e. that of true MFB) still has unexplored potential.
Meyer qualifies Philips' attempt as "disastrous" and "underwater sound", Would you expect praise from a competitor? Hands up all Slashdotters who have actually listened to a set of MFB speakers....
The opposite approach: Motional Feedback
on
Giant Sub-Woofer
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· Score: 1
MFB drivers have an acceleration sensor and a FET fixed to the centre of the cone. The power amp and power supply are inside the enclosure. The sensor signal is compared with the input signal and the result is LF reproduction that is a) perfectly linear down to any desired cutoff frequency and b) unaffected by changes in mechanical and electrical properties of all components.
I have a miniature set (4" driver, 8 litre, fully enclosed, 2-way) with -3dB point adjusted to 20 Hz that has kept me drooling for almost 30 years now. Obviously the acoustical pressure is limited by Doppler distortion but the quality of the LF reproduction is such that I am completely satisfied with the modest available sound level. Larger versions were also made at the time but the market rejected the idea so Philips pulled the plug on it. Fortunately these things seem to last for ever. They can be plugged into any headphone output. There is even an MFB owners club!
Actually it says "Thermal/field emission type" which is shorthand for "Thermally assisted field emission type", otherwise known as a Schottky field emitter. Standard SEM (scanning electron microscope) mechanism would be a better description than standard CRT mechanism.
Excellent posting. I wish all Slashdot postings were of the same quality, and that we were spared the junk we have to wade through every time in order to find the good stuff.
However allow me to pick one nit: chromatic aberration is usually not the limiting factor. It is only a serious problem at ultra-high resolution (= atomic) or very low accelerating voltage (= sub-kiloVolt). On the other hand even without a monochromator the brightness of a thermal emitter is so much lower - in fact 4 to 5 orders of magnitude - than that of a field emitter, that it would take far too long to make the discs.
Such partitions, in crude form, could certainly be constructed, and they will hardly hold up the general development.
The range of an electron in a solid depends mainly on its initial energy. For a 30 keV electron (such as found in a cathode ray tube) it is in the order of one micrometer, so Bush's "partition" would have to be much thinner than a micrometer. At the same time it would have to withstand a pressure differential of one atmosphere! Engineers have grappled with this particular problem since the invention of the transmission electron microscope in the 1930's. In all the years since then nobody has managed to construct such a "partition" because it is obviously impossible. Instead workarounds were developed which in turn are gradually being superseded by solid state image sensor technology.
Well intended Fun Guy, but unfortunately irrelevant. As indicated by the AC above, images such as these are only possible with a transmission electron microscope or TEM, at least for now and in the foreseeable future. Atomic resolution requires at least 200 kV electron acceleration voltage, immersion type magnetic objective lenses (lenses where the specimen is at the point of maximum magnetic field), and detection of the weakly scattered high energy primary electrons, not the occasional low energy secondary electrons.
The amount of "bounceback" or backscattering - as it's known as in the field - from a few carbon atoms is too small to be of any use and would be completely swamped by the backscattered (and the secondary) electrons from the gazillions of water molecules surrounding the specimen in an ESEM. The specimen has to be in a near perfect vacuum in order to avoid that. Read the second paragraph of your description which explains that the ESEM detects the secondary electrons, not the backscattered primary electrons.
The TEM itself is basically off-the-shelf machinery. Nevertheless only very experienced microscopists can coax such performance from a TEM and then only after countless hours of patient toil. Chapeau from a colleague, guys!
Say what you will about Trabant (and I've read a lot of nonsense here and elsewhere about it) - I owned two of them in the '70s and I can tell you that was far and away the most economical car I have or will ever come across.
At 40 mpg the fuel consumption was quite good. Its main secret was its simplicity. The list of components found in ordinary cars which the Trabant did not have is longer than the list of those it did have. Like: poppet valves, camshaft, timing belt, HT distributor, water pump, oil pump, fuel pump, servo steering, ditto brakes, any form of electronics, etc. etc.. There were only two leaf springs for four wheels. Oh yes, and sound proofing was practically non-existant!
So essentially there was no maintenance because there was nothing to maintain. The few parts that were there were good enough. The only parts I ever replaced in 50.000 kms were the ignition coils. The Duroplast body panels were much more dent-resistant than present-day sardine tins. Unfortunately the steel body was just as rust-prone as that of contemporary competitors. However crash tests carried out after the Wall fell proved that the shell was actually much stronger than most people thought.
Anyway both my Trabants eventually succumbed to big-end seizure, probably because I ignored the advice in the owners manual to refrain from cruising at full throttle (70 mph). I didn't bother to replace the crankshafts but I could have - one man could extract the engine without a hoist.
The description by Forbes is basically vague hearsay. Judging a car by the sound of its name is stupid. Their assessment of the durability of Duroplast is plain wrong. Borgward was a West German make. For 8 years my family car was a Wartburg. Bigger and faster but same KISS philosophy as the Trabant, second most economical car. With a name like Forbes, some magazines on the net just seem to shout "junk"!
Well said, Pfafrich. The overriding importance of Open Standards cannot be overemphasized. Although it won't be easy, the job of selecting preferred open standards should really be carried out at the highest possible level, i.e. the EU. Or the UN.... one can dream.....
I live in the Netherlands. For on-line banking my bank (SNS) supplies a thing they call a 'digipas' which I think is better known as a Vasco token. AFAIK this device does not have a clock. In order to log on to your account you copy the serial number from the rear of the digipas and the bank returns an 6-digit number. You activate the Vasco token, enter your 5-digit PIN and then the 6-digit number. The device returns a different 6-digit number with which you can log in.
Different dutch banks have different systems. This one seems pretty secure to me.
Slashdot Mirror
Quite the contrary: the high temperature heat collected by CSP systems (Concentrating Solar Power) can be stored for later use in cheap media such as gravel. Storage for upkeep of electricity production during the night is economically feasible, storage for bridging longer periods is not. It is cheaper to have a fuel-fired auxiliary boiler in the system for the occasional instances when the stored heat is exhausted.
Solar cells and wind turbines rely on backup by conventional power plants because they cannot produce electricity on demand. Concentrating Solar Power (i.e. solar thermal electricity generation) differs fundamentally because the collected heat can be stored relatively cheaply and used to sustain production during the night. Occasionally the storage will be insufficient, in those cases a simple fossil fueled boiler can temporarily take care of the steam supply for the turbine. Large scale deployment of Concentrating Solar Power (i.e. solar thermal electricity generation) could bring the cost down to less than 6$c/kWh within 20 years. High Voltage DC technology for economical transportation of electricity over very large distances is already available. It's been said before but bears repeating that a small part of the worlds deserts can capture enough solar power to satisfy the worlds total energy demand for transport, heating as well as electricity. There is every reason to pump at least as much taxpayers money into the deployment of CSP as is now the case for other renewables. The biggest hurdle for governments and investors is the fact that in order to be economical, CSP plants must be big (in the order of 100 MW) and situated in deserts, which for most countries means outside their own borders and therefore requires close international cooperation. Ignorance of technology in general and CSP in particular of the media, politicians and the public at large is the other big problem. Most of them still think there is only one kind of solar power and in several years of lobbying for CSP I have found that you have to explain the basics two, three or even more times before the message begins to percolate through to the brain. There is plenty of solid information about CSP all over the www. If you can read Dutch, take a look at our website: www.gezen.nl
You forget the five Solar Thermal plants at Kramer Junction which together produce 165 MW. SEGS III - VII, as they are called, have been in commercial operation for around twenty years now. These are definitely utility scale plants, not demonstration plants.
Concentrating Solar Thermal Power plants have been in successful operation for decades in California. Note how the article avoids any mention of them, instead comparing Concentrating Solar PV with non-concentrating Si-PV. Note also how proponents of solar PV (and of wind turbines) always "forget" to mention the biggest drawback, which is the fact that they only produce electricity when the sun shines or the wind blows. CSTP differs fundamentally in that the energy is collected in the form of high temperature heat, which can be temporarily stored by various methods. This means that the electricity production can be fully controlled and that production can be sustained 24 hours a day. The largest single CSTP plant has been turning out 80MW for almost 20 years now. Low fossil fuel prices made further development temporarily unattractive but the rate of development and deployment is picking up again for obvious reasons. Once the learning curve kicks in the price of CSTP will gradually go from the current 12 c/kWh to something like 5 c/kWh. Include the cost of all the back-up power needed for intermittent solar-PV and wind power and it is obvious that they will never be able to compete with CSTP in time to solve the upcoming energy crisis.
I admit not having read the linked article. I have now and didn't see anything new. The statement that excessive wind power was probably a primary factor was made the next day by Marcel Bial, head of the UCTE (transmission coordinators), however the detailed analysis is still ongoing and the final report will be issued in a fortnight.
For me this was an opportunity to draw attention to the widespread misconception that all forms of solar electricity production are equal in the sense that they only work when the sun shines. Solar Thermal is different because it collects the suns heat and utilizes that to power a heat engine such as a steam turbine. The point is that (high temperature) heat can be stored economically for a reasonable period whereas electricity from e.g. PV cells and wind turbines cannot.
If you are curious about CSP I suggest visiting www.solarpaces.org as a good starting point.
Nope.
The primary cause was overload of the network due to excess production of wind energy. In Germany the wind turbine operators are allowed to pump all the electrcity into the net that they can produce and the utilities are compelled by law to deal with it. Overloads will become more frequent as more and bigger turbines are brought online. The latest multi-megawatt turbines can produce electricity relatively economically but they are not so economical if one includes the hidden costs of compensating for the enormous variations in power output.
The only viable long-term large-scale solution is some form of solar power. Concentrating Solar Thermal Power is the most promising option in my book because we already know that it works, we know that it can be cheap in the long run, that it can guarantee 24/7 production by including heat storage and that there is more than enough of it on tap. Wind and PV solar are simply too fickle to rely on. Anything a nuclear boiler can do, the sun can do better. Nuclear reactors are limited to about 1000 degrees Celsius, solar boilers can go far beyond that. They have enormous potential for the production of e.g. fuels for transport purposes such as hydrogen or hydrocarbons from atmospheric carbon dioxide.
Quotation from the article: "Wind and solar power have their place, but because they are intermittent and unpredictable they simply can't replace big baseload plants such as coal, nuclear and hydroelectric."
Apparently Moore has never heard of Concentrating Solar Power. This is a proven technology which, combined with heat storage, can replace all the baseload plants in the world. Although the heat storage part is still in a more or less experimental phase, there is no doubt that it can be done.
The best and most economical place to build CSP power stations happens to be in hot arid areas, where nobody wants to live anyway. Instead of being detrimental to the environment, the shade of the collector fields will probably be beneficial to the local environment. The current state of High Voltage Direct Current technology is such that one cable can transport over 6 gigawatts of electricity over thousands of kilometers. This is already being done in China.
Moore and the collective Slashdot crowd should be ashamed of themselves for completely ignoring this option.
A detailed plan for generating electricity in the Sahara already exists. The technology is called Concentrating Solar Power or CSP and has already proved itself on a large scale in the Mojave Desert. The details have been worked out by TREC, the Trans-Mediterranean Energy Cooperation. See http://www.trec-eumena.org/
The results of the EU ECOSTAR CSP program have just been released at a workshop held last thursday in Brussels. The 140-page report can be downloaded from ftp://ftp.dlr.de/ecostar. CSP power stations occupying an area the size of France in the Sahara, using available technology, can produce the current total energy consumption of the whole world.
Nowhere does the originating paper in Nature mention the prospects of the device as a photovoltaic conversion system. However one of the figures shows that when it is irradiated with 70 milliwatts of infrared light, it can deliver 130 nanoamps at 180 millivolts. The product of the latter two values is 23.4 nanowatts. Hence the energy conversion efficiency is 0.00003%, or roughly one millionth of the conversion efficiency of a Concentrating Solar Power electricity generating plant such as the one at Kramer Junction in CA. A CSP system also has the ability to store heat collected during the day so it can continue production during the night. No PV system can ever compete with that.
The parent makes a few good points. However the design of the Prius powertrain is so unorthodox that almost everyone misses the really cunning part, which is that it actually has two transmissions working in parallel. The power from the IC engine (when it's running) is partitioned among them by a differential drive. One part goes to the infinitely variable electrical CVT (= generator + motor) and the other part goes straight to the wheels.The transmission ratio of this part is essentially that of top gear.
When cruising all the power is transmitted by the direct drive and none by the electric motor. That only provides the additional torque when more torque is required than top gear can provide, therefore the additional electrical losses are only incurred when you put your foot down.
The second point that is usually missed is the fact that the Prius sports an Atkinson cycle engine, which is more efficient at part load than the usual Otto cycle engine. The Atkinson cycle goes a long way towards making up the difference in efficiency between the Otto and the Diesel cycle at part load.
As usual, the collective Slashdot memory is short. The German company IAV pushed the envelope of steam power for wheeled vehicles way beyond Bowshers design and published their results in 2001. Check it out at http://www.iavinc.com/alternativedrives.html
The company is Radiation Shield Technologies and Demron is name of the product. It is up to them to point others to credible independent proof of their claims if there is any. As you can see here: http://www.vanderbilt.edu/radsafe/0211/msg00186.ht ml I'm not the only skeptical pro. IAAP (=physicist); sorry about the typo in my previous post.
As others have already pointed out, the stuff you are referring to is Demron, manufactured by RST. When I first heard of it a year or so ago I found their claim regarding its extraordinary X-ray absorbing capability very hard to believe in the light of well-established physical model of the absorption of EM radiation by matter. The report published by Lawrence Livermore Lab. was funded by RST and the author did not respond to my request for a scientific explanation.
Until the results have been independently verified and published in a peer-reviewed journal, or else verified by myself, I will continue to have grave doubts concerning their claim. (IIAP and part of my job is monitoring the radiation safety of X-ray emitting apparatus.)
Actually it's not beta radiation (= electrons emitted by nuclei). The electrons emitted by the cathode and accelerated to 30+ kV do not penetrate the glass. They excite the screen to produce visible light and the undesireable byproduct is 30+ kV X-rays which have far greater penetrating power, hence the X-ray absorbing lead in the glass.
Thanks for the reference. Note that Meyer's design involves measuring the air pressure in front of the cone with a microphone, and that on a reflex system where lots of sound is bypassing said microphone. This is a far cry from Philips' KISS design philosophy and cannot be classified as motional feedback. No wonder Meyer says "this is a very complex problem to solve, and one that has defeated all previous attempts"! However MFB does not constitute a "previous attempt" to solve the problem he set himself.
I am aware of the discussion about the perceived quality of sound reproduction of Philips' MFB range, but chose not to bring it up as it would take us off topic. Actually the closed loop motion control only operates up to 500 Hz and the 4" driver carries on passively up to the crossover point at 1500 Hz (also passive) where the tweeter takes over. In other words the MF and HF department is uninteresting. However the LF and especially the VLF part remains unique and I feel that the fundamental principle (i.e. that of true MFB) still has unexplored potential.
Meyer qualifies Philips' attempt as "disastrous" and "underwater sound", Would you expect praise from a competitor? Hands up all Slashdotters who have actually listened to a set of MFB speakers....
MFB drivers have an acceleration sensor and a FET fixed to the centre of the cone. The power amp and power supply are inside the enclosure. The sensor signal is compared with the input signal and the result is LF reproduction that is a) perfectly linear down to any desired cutoff frequency and b) unaffected by changes in mechanical and electrical properties of all components.
I have a miniature set (4" driver, 8 litre, fully enclosed, 2-way) with -3dB point adjusted to 20 Hz that has kept me drooling for almost 30 years now. Obviously the acoustical pressure is limited by Doppler distortion but the quality of the LF reproduction is such that I am completely satisfied with the modest available sound level. Larger versions were also made at the time but the market rejected the idea so Philips pulled the plug on it. Fortunately these things seem to last for ever. They can be plugged into any headphone output. There is even an MFB owners club!
Actually it says "Thermal/field emission type" which is shorthand for "Thermally assisted field emission type", otherwise known as a Schottky field emitter.
Standard SEM (scanning electron microscope) mechanism would be a better description than standard CRT mechanism.
Excellent posting. I wish all Slashdot postings were of the same quality, and that we were spared the junk we have to wade through every time in order to find the good stuff.
However allow me to pick one nit: chromatic aberration is usually not the limiting factor. It is only a serious problem at ultra-high resolution (= atomic) or very low accelerating voltage (= sub-kiloVolt). On the other hand even without a monochromator the brightness of a thermal emitter is so much lower - in fact 4 to 5 orders of magnitude - than that of a field emitter, that it would take far too long to make the discs.
Such partitions, in crude form, could certainly be constructed, and they will hardly hold up the general development.
The range of an electron in a solid depends mainly on its initial energy. For a 30 keV electron (such as found in a cathode ray tube) it is in the order of one micrometer, so Bush's "partition" would have to be much thinner than a micrometer. At the same time it would have to withstand a pressure differential of one atmosphere! Engineers have grappled with this particular problem since the invention of the transmission electron microscope in the 1930's. In all the years since then nobody has managed to construct such a "partition" because it is obviously impossible. Instead workarounds were developed which in turn are gradually being superseded by solid state image sensor technology.
Well intended Fun Guy, but unfortunately irrelevant. As indicated by the AC above, images such as these are only possible with a transmission electron microscope or TEM, at least for now and in the foreseeable future. Atomic resolution requires at least 200 kV electron acceleration voltage, immersion type magnetic objective lenses (lenses where the specimen is at the point of maximum magnetic field), and detection of the weakly scattered high energy primary electrons, not the occasional low energy secondary electrons.
The amount of "bounceback" or backscattering - as it's known as in the field - from a few carbon atoms is too small to be of any use and would be completely swamped by the backscattered (and the secondary) electrons from the gazillions of water molecules surrounding the specimen in an ESEM. The specimen has to be in a near perfect vacuum in order to avoid that. Read the second paragraph of your description which explains that the ESEM detects the secondary electrons, not the backscattered primary electrons.
The TEM itself is basically off-the-shelf machinery. Nevertheless only very experienced microscopists can coax such performance from a TEM and then only after countless hours of patient toil. Chapeau from a colleague, guys!
Say what you will about Trabant (and I've read a lot of nonsense here and elsewhere about it) - I owned two of them in the '70s and I can tell you that was far and away the most economical car I have or will ever come across.
At 40 mpg the fuel consumption was quite good. Its main secret was its simplicity. The list of components found in ordinary cars which the Trabant did not have is longer than the list of those it did have. Like: poppet valves, camshaft, timing belt, HT distributor, water pump, oil pump, fuel pump, servo steering, ditto brakes, any form of electronics, etc. etc.. There were only two leaf springs for four wheels. Oh yes, and sound proofing was practically non-existant!
So essentially there was no maintenance because there was nothing to maintain. The few parts that were there were good enough. The only parts I ever replaced in 50.000 kms were the ignition coils. The Duroplast body panels were much more dent-resistant than present-day sardine tins. Unfortunately the steel body was just as rust-prone as that of contemporary competitors. However crash tests carried out after the Wall fell proved that the shell was actually much stronger than most people thought.
Anyway both my Trabants eventually succumbed to big-end seizure, probably because I ignored the advice in the owners manual to refrain from cruising at full throttle (70 mph). I didn't bother to replace the crankshafts but I could have - one man could extract the engine without a hoist.
The description by Forbes is basically vague hearsay. Judging a car by the sound of its name is stupid. Their assessment of the durability of Duroplast is plain wrong. Borgward was a West German make. For 8 years my family car was a Wartburg. Bigger and faster but same KISS philosophy as the Trabant, second most economical car. With a name like Forbes, some magazines on the net just seem to shout "junk"!
Installed without a hitch on an eMac and a Bondi iMac, both running OSX 10.2.8.
Well said, Pfafrich. The overriding importance of Open Standards cannot be overemphasized. Although it won't be easy, the job of selecting preferred open standards should really be carried out at the highest possible level, i.e. the EU. Or the UN .... one can dream.....
May I suggest looking both verbs up in a dictionary?
I live in the Netherlands. For on-line banking my bank (SNS) supplies a thing they call a 'digipas' which I think is better known as a Vasco token. AFAIK this device does not have a clock. In order to log on to your account you copy the serial number from the rear of the digipas and the bank returns an 6-digit number. You activate the Vasco token, enter your 5-digit PIN and then the 6-digit number. The device returns a different 6-digit number with which you can log in.
Different dutch banks have different systems. This one seems pretty secure to me.