For a long time Hollands one and only astronaut Wubbo Ockels (that is if you discount Laurens van den Berg who beat Ockels into space by emigrating to the USA) was an enthusiastic proponent of the space elevator idea. One of his jobs is Professor of Space Science at Delft Technical University. However when I asked him earlier this year how the work was progressing he just grinned and then proceeded to describe a new and grandiose project consisting of whole cities in geostationary orbit that would be strung together like a string of pearls on an ultrastrong cable around the equator.
Obviously this would put far less extreme demands on the strength/weight ratio of the string material. However the problem of the elevator would remain and he was not aware of any real progress on that front. As a materials scientist I think it's all pie in the sky.
Since information is so scarce, they are free to speculate (or let the media speculate) as much as they like. Could you resist the temptation to do so if you were in that situation? Reference point: State-of-the-art IC engine technology hes been stuck at around 50% brake thermal efficiency for decades. This goes for reciprocating and rotating machinery. I see no fundamental reason why a PDE should have a higher potential; I expect that once all the loss mechanisms are understood they will turn out to produce at best the same end result.
You are confusing dutch and deutsch (german) which, although understandable in this case because the only difference is the t at the end which you omit, still makes you look slightly stupid! However I note with some satisfaction that this type of mistake is very rare nowadays.
The original paper explains how they squeezed their own experiment into a conventional TEM set-up consisting of an environmental cell in an intermediate voltage Hitachi TEM equipped with a Gatan energy filter. The final magnified image is captured from a fluorescent screen with a monochrome video camera. If a higher frame rate were necessary all it would require is a different CCD with a higher clock rate. The TEM itself produces a continuous image just like a light microscope.
The emphasis put by C/Net on IBM's 'dominant' position in the EM field is amusing; over the years IBM have made important contributions to the technology of imaging with charged particles but never produced EM's etc. in series. The equipment used here is from Hitachi, Gatan and FEI (formerly Philips)! The energy filter is the part that helps to enhance the contrast between the small copper clusters and all the other comparatively thick objects in the path of the electrons. It can be compared to the effect of a highly selective colour filter in the case of a visible light image.
Nice work by IBM, pity C/Net didn't quite get the right perspective.
All Thunderbirds are dedicated to the memory of the Truimph Thunderbird motorcycle of the 1950's.
Commuter bike technology is still backward
on
Sports Technology?
·
· Score: 1
Living in The Netherlands, a bicycle is for me primarily an efficient means of transport. Offroad capabilities are irrelevant, weight is of minor importance. I need a bike that is comfortable, has room for luggage, will stand rough handling, dutch weather and brine, and requires minimal maintenance. This can be achieved by careful choice of materials (corrosion-resistant) and sensible design. For me sensible means a fully enclosed chain, well laid control cables and electrics (including a hub dynamo) and fully enclosed journal ball bearings everywhere instead of antiquated cup and cone bearings that are the devil to adjust.
It buggers me no end that with all the advances in bike technology I still can't purchase a bike that fulfils these modest requirements for a reasonable price. Leave an expensive bike standing outside a store here and you can almost count on it being nicked before you come back for it. That is probably the main reason why people here tend to buy cheap mass-produced trash, so there is not enough incentive for the development of quality commuter bikes. Oh well.
I have taken a closer look at MDI's website. As far as I can make out (it's in French) they have one prototype which looks good but has conventional compressed air technology under the hood. It's actual measured range is a modest 7.22 km. By smart engineering they expect to raise that to 242 km. I prefer to call it wishful thinking; I'd be surprised if they manage to exceed 24.2 km.
Nice to see someone actually checking the references. According to MDI they compress 90 m3 of air to 90 litres at 300 bar. This is nowhere near what one would expect according to Boyles law (P*V = constant for isothermal compression). Assuming the 300 bar is correct, then either the figure for the initial volume or that for the compressed volume is incorrect. The initial volume was probably never actually measured because it is technically irrelevant. Therefore I used the values 300 bar and 90 litres in the formula P*V*log(pressure ratio).
Until an independent person verifies MDI's claims by actually driving the thing until it runs out of air I will stick to my conclusion that it is an elaborate hoax. However good looking the mock-ups are they still can't circumvent the time tested laws of physics.
MDI states that the Air Car stores 90 litres of air at 300 bar. The stored energy is then approximately PVlog300 where P and V are the compressed pressure and volume. This amounts to about 15 MJ or 4.3 kWh. Divide this by the range of 300 km and we find a tractive force of 50 Newtons, meaning that the vehicle can be propelled by pushing it with one finger!
Unfortunately the Air Car is a fata morgana and a bottomless pit for investors. Clueless journalists - probably slept during physics class.
The nanotech engine looks very far from production ready - two or three unclear images, and an interview, that's it. The video is mainly marketing for Birmingham Uni, AFAICS, and almost entirely void of technical details or facts.
Hear, Hear. Miniature engines are sexy projects for demonstrating micro-machining capabilities but they invariably disappear from the radar after the initial media flurry. The inventors are so excited about their projects that they overlook the inevitable effects of downscaling on IC engines. The most important effect is that of flame quenching at the relatively cool walls of the combustion chamber. This occurs at around.5 mm from the chamber wall, irrespective of the size of the chamber. The few miniature engines that have actually operated under their own power are nudging this limit and, not surprisingly, have very incomplete combustion resulting in very low efficiency and extremely polluting emissions.
At least the folks at Berkeley did their homework. They list the following research issues:
Quenching Effect
Engine Sealing
Friction/Lubrication
Fuel Carburetion
Thermal Management
Engine Diagnostics
Ignition
Ancillary Equipment/Packaging for an Autonomous System
The first two effectively rule out anything with combustion chambers smaller than 1 mm. I'd be amazed if someone can make a working micro-engine, sadly it's just a pipe dream.
Now if only they'd put some real emissions requirements on lawn equipment and other small engines, and ban two-strokes.
What would be the point of banning two-strokes built to satisfy "real emission requirements"? Apparently you are not aware of the enormous diversity of power plants operating on the two-stroke principle. I presume you are alluding to the ultra-simple variety with which low priced vehicles and appliances are equipped. There are already engineering solutions available, such as direct fuel injection, for controlling their emissions to any reasonable degree. Put emission requirements in place and the two-stroke manufacturers will be ready for them.
Legislators should not, and AFAIK do not, regulate the operating principles of vehicles, only put upper or lower limits on weight, size, performance, emissions etc. Banning two-strokes per se would be a stupid way to stifle innovation in IC engine design.
Sorry to burst your balloon, but this story about the inefficiency of the classical conrod/crankshaft system is nonsense from a kinematical point of view. If there are any independent tests that can confirm the results claimed by the team you refer to for their modified linkage I'd love to hear of it. Of one thing you can be sure though: complicated linkages severely limit engine revs so using them will automatically obviate the need for solenoid powered poppet valves.
Nevertheless I agree with the gist of your closing remark about expense, complexity and reliability. You are obviously interested in vehicle design but perhaps not aware of the fact that everything you (or I) can think of has already been thought of, proposed and patented. For example work on the so-called adiabatic diesel engine has been going on for nearly a century. Although purely adiabatic operation (i.e. without heat exchange) is practically impossible, German engineer Ludwig Elsbett for example has modified the injection and combustion of standard automobile engines to the point that he could dispense with the whole cooling water circuit. In order to achieve this he perfected the technique of stratified charging.
There is however one design of hybrid engine that is such a radical departure from known designs that only very few folks are aware of its existence. This is the Innas free piston hydraulic generator, prototypes of which have achieved over 35% overall energy efficiency. This not the place for a detailed analysis. The important part is the fact that its efficiency at light load (as in urban traffic) is only slightly lower than optimum whereas in conventional engines it drops dramatically under those conditions. Unfortunately I do not have any quick links but if anyone is really interested I might be able to dig something out of my archives.
A regional newspaper (Dagblad van het Noorden) happened to carry a short interview with Bluetooth inventor Jaap Haartsen on June 7th. Here is a translation for the unfortunate few who cannot obtain the DvhN or read dutch.
Ericssons move from E mmen gives Bluetooth inventor sleepless nights
(A short introduction explains that dutchman Jaap Haartsen developed the chips with which devices such as telephones and laptops can communicate over short distances, however AFAIK he designed the protocol as well.) The Bluetooth Innovation Center, the company Haartsen works for, is moving to Lund in Sweden. This means that Bluetooth R&D also leaves Emmen.
The Bluetooth lab is leaving Emmen. That must make you feel sad.
âoeItâ(TM)s a shock. For me personally and for everyone here. The managementâ(TM)s decision has given me sleepless nights. I am sad that the Bluetooth lab is leaving The Netherlands.
What are you going to do at Ericsson now?
âoeThe peop le in Emmen have the option to move to Sweden. I havenâ(TM)t decided yet. I am a member of the Bluetooth management team and I already go to Sweden every other week. But the home base, my office in Emmen, is closing down. I will remain closely involved with B luetooth; after all it is my baby, as it were.â
No doubt you strongly opposed the move from Emmen?
âoeYou bet I did. I was involved in the discussions over the plan. We tried to keep open the possibility of staying in Emmen. However the parent companyâ(TM)s interests were deemed more important. Ericsson has to survive the economic dip so we had to accept the closure.â
Ericsson is lowering its R&D budget. That means they are investing less in their future. Surely that is not a sensible thing to do?
âoeTimes are hard and you have to earn the income that pays for the R&D. The parent company is striving for a balance. On the one hand one must be ready for the future, on the other hand one must survive. For the time be ing the focus is on sales. You can maintain the level of investment and wait until the plug is pulled out completely, or you can act now. That is what is happening now.â
The expectations concerning the sales of Bluetooth chips were high. It has not been an unmitigated success to date.
âoeThe long term outlook is good. The market is reviving.â
Weâ(TM)ve heard that before regarding Bluetooth.
âoeThe number of telephones equipped with Bluetooth chips is growing with leaps and bounds. The same is true for other products. The development of that market is very promising. The semiconductor industry is now increasing its production capacity for Bluetooth chips. Thatâ(TM)s going in the right direction as well.â
In this case we are talking about direct injection, so no fuel is wasted. Experimental DI two-strokes have repeatedly demonstrated remarkable efficiency, especially under part load, so think again before you bet!
Spark ignition two-strokes invariably have crankcase scavenging, Diesel two-strokes have separate scavenge pumps. Any engine employing crankcase scavenging eventually loses its oil through the combustion chamber, however decades of work on engine design and lubricants allow the use of ridiculously lean oiling ratios (like 200:1) with clean-burning bio-degradable lubricants. The current breed of two-strokes such as seen on European roads is virtually smoke free. Racing two-strokes still use premix - you can't beat it for reliability!
It is true that NOx production is a problem common to all IC engines. It is however also an established fact that the retention of exhaust gases inherent in all two-strokes appreciably lowers peak cycle temperatures. Therefore two-strokes with modest power output and hence modest bmep (brake mean effective pressure) emit negligible amounts of NOx and the Aqwon is probably no exception.
Sorry to burst your bubble, but the Air Car is nothing more than an elaborate hoax. Note that the information supplied by MDI is all about 'predicted' performance, however none of the people who have actually set eyes on the bi-energy prototype or the new compressed-air-only engine has been able to verify MDI's claims.
I estimate the useful energy storage capacity to be something like 3 kWh for 90 litres at 300 bar, using basic physics and assuming an ideal gas. There is no way any vehicle of that size is going to travel up to 300 km at around 100 kmph on the equivalent of five 50 Ah car batteries.
Your comment on the media reminded me of the Quantum Afterburner episode. The QA was a silly idea put forward by Marlan Scully about a year ago in Physical Review Letters (050602) and I am still wondering why it was accepted. Within days it was covered by Physics World, New Scientist, Science and TRN News. The respective reporters obviously had absolutely no idea what they were writing about! As you say - in the media, accuracy is always second to newsworthiness and speed.
It will be interesting to see how the funding bodies (NSF, ONR, AFOSR etc.) will view this when Scully has to report that after all his QA won't do what it's supposed to, i.e. save gas. He expected to have a working device within "a year or two". If he forgets to inform us of his progress I intend to remind him of his obligation to do so.
Slashdot Mirror
For a long time Hollands one and only astronaut Wubbo Ockels (that is if you discount Laurens van den Berg who beat Ockels into space by emigrating to the USA) was an enthusiastic proponent of the space elevator idea. One of his jobs is Professor of Space Science at Delft Technical University. However when I asked him earlier this year how the work was progressing he just grinned and then proceeded to describe a new and grandiose project consisting of whole cities in geostationary orbit that would be strung together like a string of pearls on an ultrastrong cable around the equator.
Obviously this would put far less extreme demands on the strength/weight ratio of the string material. However the problem of the elevator would remain and he was not aware of any real progress on that front. As a materials scientist I think it's all pie in the sky.
Bit of a rant, I'm sorry, please bare with me.
Certainly not. How dear you!
Since information is so scarce, they are free to speculate (or let the media speculate) as much as they like. Could you resist the temptation to do so if you were in that situation? Reference point: State-of-the-art IC engine technology hes been stuck at around 50% brake thermal efficiency for decades. This goes for reciprocating and rotating machinery. I see no fundamental reason why a PDE should have a higher potential; I expect that once all the loss mechanisms are understood they will turn out to produce at best the same end result.
1. A gas turbine is an IC engine.
2. Various IC piston engines have successfully been converted to operate reliably with hydrogen decades ago.
3. Although H2 permits high compression ratios, it does not require them. The same applies to LPG.
4. The main obstacle is therefore not satisfactory engine operation, but the hydrogen infrastructure.
You are confusing dutch and deutsch (german) which, although understandable in this case because the only difference is the t at the end which you omit, still makes you look slightly stupid! However I note with some satisfaction that this type of mistake is very rare nowadays.
The original paper explains how they squeezed their own experiment into a conventional TEM set-up consisting of an environmental cell in an intermediate voltage Hitachi TEM equipped with a Gatan energy filter. The final magnified image is captured from a fluorescent screen with a monochrome video camera. If a higher frame rate were necessary all it would require is a different CCD with a higher clock rate. The TEM itself produces a continuous image just like a light microscope.
The emphasis put by C/Net on IBM's 'dominant' position in the EM field is amusing; over the years IBM have made important contributions to the technology of imaging with charged particles but never produced EM's etc. in series. The equipment used here is from Hitachi, Gatan and FEI (formerly Philips)! The energy filter is the part that helps to enhance the contrast between the small copper clusters and all the other comparatively thick objects in the path of the electrons. It can be compared to the effect of a highly selective colour filter in the case of a visible light image.
Nice work by IBM, pity C/Net didn't quite get the right perspective.
All Thunderbirds are dedicated to the memory of the Truimph Thunderbird motorcycle of the 1950's.
Living in The Netherlands, a bicycle is for me primarily an efficient means of transport. Offroad capabilities are irrelevant, weight is of minor importance. I need a bike that is comfortable, has room for luggage, will stand rough handling, dutch weather and brine, and requires minimal maintenance. This can be achieved by careful choice of materials (corrosion-resistant) and sensible design. For me sensible means a fully enclosed chain, well laid control cables and electrics (including a hub dynamo) and fully enclosed journal ball bearings everywhere instead of antiquated cup and cone bearings that are the devil to adjust.
It buggers me no end that with all the advances in bike technology I still can't purchase a bike that fulfils these modest requirements for a reasonable price. Leave an expensive bike standing outside a store here and you can almost count on it being nicked before you come back for it. That is probably the main reason why people here tend to buy cheap mass-produced trash, so there is not enough incentive for the development of quality commuter bikes. Oh well.
I have taken a closer look at MDI's website. As far as I can make out (it's in French) they have one prototype which looks good but has conventional compressed air technology under the hood. It's actual measured range is a modest 7.22 km. By smart engineering they expect to raise that to 242 km. I prefer to call it wishful thinking; I'd be surprised if they manage to exceed 24.2 km.
YMMV!
Nice to see someone actually checking the references. According to MDI they compress 90 m3 of air to 90 litres at 300 bar. This is nowhere near what one would expect according to Boyles law (P*V = constant for isothermal compression). Assuming the 300 bar is correct, then either the figure for the initial volume or that for the compressed volume is incorrect. The initial volume was probably never actually measured because it is technically irrelevant. Therefore I used the values 300 bar and 90 litres in the formula P*V*log(pressure ratio).
Until an independent person verifies MDI's claims by actually driving the thing until it runs out of air I will stick to my conclusion that it is an elaborate hoax. However good looking the mock-ups are they still can't circumvent the time tested laws of physics.
MDI states that the Air Car stores 90 litres of air at 300 bar. The stored energy is then approximately PVlog300 where P and V are the compressed pressure and volume. This amounts to about 15 MJ or 4.3 kWh. Divide this by the range of 300 km and we find a tractive force of 50 Newtons, meaning that the vehicle can be propelled by pushing it with one finger!
Unfortunately the Air Car is a fata morgana and a bottomless pit for investors. Clueless journalists - probably slept during physics class.
The nanotech engine looks very far from production ready - two or three unclear images, and an interview, that's it. The video is mainly marketing for Birmingham Uni, AFAICS, and almost entirely void of technical details or facts.
.5 mm from the chamber wall, irrespective of the size of the chamber. The few miniature engines that have actually operated under their own power are nudging this limit and, not surprisingly, have very incomplete combustion resulting in very low efficiency and extremely polluting emissions.
Hear, Hear. Miniature engines are sexy projects for demonstrating micro-machining capabilities but they invariably disappear from the radar after the initial media flurry. The inventors are so excited about their projects that they overlook the inevitable effects of downscaling on IC engines. The most important effect is that of flame quenching at the relatively cool walls of the combustion chamber. This occurs at around
At least the folks at Berkeley did their homework. They list the following research issues:
Quenching Effect
Engine Sealing
Friction/Lubrication
Fuel Carburetion
Thermal Management
Engine Diagnostics
Ignition
Ancillary Equipment/Packaging for an Autonomous System
The first two effectively rule out anything with combustion chambers smaller than 1 mm. I'd be amazed if someone can make a working micro-engine, sadly it's just a pipe dream.
Now if only they'd put some real emissions requirements on lawn equipment and other small engines, and ban two-strokes.
What would be the point of banning two-strokes built to satisfy "real emission requirements"? Apparently you are not aware of the enormous diversity of power plants operating on the two-stroke principle. I presume you are alluding to the ultra-simple variety with which low priced vehicles and appliances are equipped. There are already engineering solutions available, such as direct fuel injection, for controlling their emissions to any reasonable degree. Put emission requirements in place and the two-stroke manufacturers will be ready for them.
Legislators should not, and AFAIK do not, regulate the operating principles of vehicles, only put upper or lower limits on weight, size, performance, emissions etc. Banning two-strokes per se would be a stupid way to stifle innovation in IC engine design.
Sorry to burst your balloon, but this story about the inefficiency of the classical conrod/crankshaft system is nonsense from a kinematical point of view. If there are any independent tests that can confirm the results claimed by the team you refer to for their modified linkage I'd love to hear of it. Of one thing you can be sure though: complicated linkages severely limit engine revs so using them will automatically obviate the need for solenoid powered poppet valves.
Nevertheless I agree with the gist of your closing remark about expense, complexity and reliability. You are obviously interested in vehicle design but perhaps not aware of the fact that everything you (or I) can think of has already been thought of, proposed and patented. For example work on the so-called adiabatic diesel engine has been going on for nearly a century. Although purely adiabatic operation (i.e. without heat exchange) is practically impossible, German engineer Ludwig Elsbett for example has modified the injection and combustion of standard automobile engines to the point that he could dispense with the whole cooling water circuit. In order to achieve this he perfected the technique of stratified charging.
There is however one design of hybrid engine that is such a radical departure from known designs that only very few folks are aware of its existence. This is the Innas free piston hydraulic generator, prototypes of which have achieved over 35% overall energy efficiency. This not the place for a detailed analysis. The important part is the fact that its efficiency at light load (as in urban traffic) is only slightly lower than optimum whereas in conventional engines it drops dramatically under those conditions. Unfortunately I do not have any quick links but if anyone is really interested I might be able to dig something out of my archives.
A regional newspaper (Dagblad van het Noorden) happened to carry a short interview with Bluetooth inventor Jaap Haartsen on June 7th. Here is a translation for the unfortunate few who cannot obtain the DvhN or read dutch.
Ericssons move from E mmen gives Bluetooth inventor sleepless nights
(A short introduction explains that dutchman Jaap Haartsen developed the chips with which devices such as telephones and laptops can communicate over short distances, however AFAIK he designed the protocol as well.) The Bluetooth Innovation Center, the company Haartsen works for, is moving to Lund in Sweden. This means that Bluetooth R&D also leaves Emmen.
The Bluetooth lab is leaving Emmen. That must make you feel sad.
âoeItâ(TM)s a shock. For me personally and for everyone here. The managementâ(TM)s decision has given me sleepless nights. I am sad that the Bluetooth lab is leaving The Netherlands.
What are you going to do at Ericsson now?
âoeThe peop le in Emmen have the option to move to Sweden. I havenâ(TM)t decided yet. I am a member of the Bluetooth management team and I already go to Sweden every other week. But the home base, my office in Emmen, is closing down. I will remain closely involved with B luetooth; after all it is my baby, as it were.â
No doubt you strongly opposed the move from Emmen?
âoeYou bet I did. I was involved in the discussions over the plan. We tried to keep open the possibility of staying in Emmen. However the parent companyâ(TM)s interests were deemed more important. Ericsson has to survive the economic dip so we had to accept the closure.â
Ericsson is lowering its R&D budget. That means they are investing less in their future. Surely that is not a sensible thing to do?
âoeTimes are hard and you have to earn the income that pays for the R&D. The parent company is striving for a balance. On the one hand one must be ready for the future, on the other hand one must survive. For the time be ing the focus is on sales. You can maintain the level of investment and wait until the plug is pulled out completely, or you can act now. That is what is happening now.â
The expectations concerning the sales of Bluetooth chips were high. It has not been an unmitigated success to date.
âoeThe long term outlook is good. The market is reviving.â
Weâ(TM)ve heard that before regarding Bluetooth.
âoeThe number of telephones equipped with Bluetooth chips is growing with leaps and bounds. The same is true for other products. The development of that market is very promising. The semiconductor industry is now increasing its production capacity for Bluetooth chips. Thatâ(TM)s going in the right direction as well.â
(End of interview)
In this case we are talking about direct injection, so no fuel is wasted. Experimental DI two-strokes have repeatedly demonstrated remarkable efficiency, especially under part load, so think again before you bet!
Spark ignition two-strokes invariably have crankcase scavenging, Diesel two-strokes have separate scavenge pumps. Any engine employing crankcase scavenging eventually loses its oil through the combustion chamber, however decades of work on engine design and lubricants allow the use of ridiculously lean oiling ratios (like 200:1) with clean-burning bio-degradable lubricants. The current breed of two-strokes such as seen on European roads is virtually smoke free. Racing two-strokes still use premix - you can't beat it for reliability!
It is true that NOx production is a problem common to all IC engines. It is however also an established fact that the retention of exhaust gases inherent in all two-strokes appreciably lowers peak cycle temperatures. Therefore two-strokes with modest power output and hence modest bmep (brake mean effective pressure) emit negligible amounts of NOx and the Aqwon is probably no exception.
Sorry to burst your bubble, but the Air Car is nothing more than an elaborate hoax. Note that the information supplied by MDI is all about 'predicted' performance, however none of the people who have actually set eyes on the bi-energy prototype or the new compressed-air-only engine has been able to verify MDI's claims. I estimate the useful energy storage capacity to be something like 3 kWh for 90 litres at 300 bar, using basic physics and assuming an ideal gas. There is no way any vehicle of that size is going to travel up to 300 km at around 100 kmph on the equivalent of five 50 Ah car batteries.
Your comment on the media reminded me of the Quantum Afterburner episode. The QA was a silly idea put forward by Marlan Scully about a year ago in Physical Review Letters (050602) and I am still wondering why it was accepted. Within days it was covered by Physics World, New Scientist, Science and TRN News. The respective reporters obviously had absolutely no idea what they were writing about! As you say - in the media, accuracy is always second to newsworthiness and speed. It will be interesting to see how the funding bodies (NSF, ONR, AFOSR etc.) will view this when Scully has to report that after all his QA won't do what it's supposed to, i.e. save gas. He expected to have a working device within "a year or two". If he forgets to inform us of his progress I intend to remind him of his obligation to do so.