5 Megawatt Nitinol Engine by Mcdonnell Douglas (2015) [video](youtube.com)
youtube.com
5 Megawatt Nitinol Engine by Mcdonnell Douglas (2015) [video]
https://www.youtube.com/watch?v=8-dCIkJAjyM
101 comments
> Clot retrievers and aneurysm closures for treatment of intracranial disease, and components for implantable drug delivery systems, are targeted areas of TiNi Alloy Company technology.
Any news on this?
Any news on this?
I don't know - it's been decades. But the history of TiNi alloy is littered with ideas which seem like they could, potentially, take advantage of its unique properties but don't ultimately pan out due to cost, difficulty of fastening the material, need for a compliant element since the alloy only works in one direction.
An interesting successful application was the Frangibolt - a non-explosive way of breaking bolts to separate components of an assembly in space.
An interesting successful application was the Frangibolt - a non-explosive way of breaking bolts to separate components of an assembly in space.
A friend who is a material scientist told me about another interesting TiNi application. I don't recall the precise details, but some sort of medical "device" that only assumes its final configuration once inside the body. You can tune the temperature response of the alloy, and so this was made "small enough" to fit (maybe through blood vessels?) and after a short time would "expand" to its intended shape. Wish I could remember more.
You're probably thinking of stents[1], used to hold open clogged arteries.
1 - https://pubmed.ncbi.nlm.nih.gov/12955452/
1 - https://pubmed.ncbi.nlm.nih.gov/12955452/
Sounds amazing. Is it used in practice?
I wonder if it could have uses for artificial hearts too
Yes used in practice! I do production support in this field.
Nitinol is used in lots of vascular devices. At least in my company, they used it first in guidewires just for the super elasticity, as a torturous vessel may kink a steel wire.
At first there were bare metal stents, steel and later CoCr alloy. But last 15 years or so we've gotten self expanding stents that use the shape memory effect to set the final diameter at body temperature during processing, then the Stent is collapsed down into a catheter delivery system. There are various designs for releasing the collapsed Stent into the vessel, but once there it springs open thanks to super elasticity and apposes (conforms) up to the vessel wall, where good apposition gives lower chance of thrombosis formation.
There are lots of other devices too... embolic protection devices (niti frame with a net over it, to catch shmoo from flowing to brain during a carotid procedure ) And various heart repair devices.
It's great for intervention devices because you can collapse a device down small enough to be advanced by radial or femoral artery access and let's you do things that would normally require cracking someone's chest open for heart surgery.
But the material is finicky, and it could take a decade for a smelter to get their niti process worked out. A very small difference in alloy composition disproportionately affects the crystal structure transition temperature, which impacts whether device will behave in service conditions
Nitinol is used in lots of vascular devices. At least in my company, they used it first in guidewires just for the super elasticity, as a torturous vessel may kink a steel wire.
At first there were bare metal stents, steel and later CoCr alloy. But last 15 years or so we've gotten self expanding stents that use the shape memory effect to set the final diameter at body temperature during processing, then the Stent is collapsed down into a catheter delivery system. There are various designs for releasing the collapsed Stent into the vessel, but once there it springs open thanks to super elasticity and apposes (conforms) up to the vessel wall, where good apposition gives lower chance of thrombosis formation.
There are lots of other devices too... embolic protection devices (niti frame with a net over it, to catch shmoo from flowing to brain during a carotid procedure ) And various heart repair devices.
It's great for intervention devices because you can collapse a device down small enough to be advanced by radial or femoral artery access and let's you do things that would normally require cracking someone's chest open for heart surgery.
But the material is finicky, and it could take a decade for a smelter to get their niti process worked out. A very small difference in alloy composition disproportionately affects the crystal structure transition temperature, which impacts whether device will behave in service conditions
This right here is what HN is for. Thank you for sharing!!
looks like a very promising field
My 6-year-old got a Nitinol device put into his heart to close a hole. They could make it small for insertion in a vein (artery?), then expand when it was in place.
That's facinating, any link on the procedure name?
From the comments:
Note that no 5 MW engine was demonstrated in this video. It's just a figure that engineer guesstimated as a plausible combined power output of multiple stacked engines. Quote at 3:05.
Note that no 5 MW engine was demonstrated in this video. It's just a figure that engineer guesstimated as a plausible combined power output of multiple stacked engines. Quote at 3:05.
From a comment
> Buehler was looking at alloys with two solid states as possible materials for the nose cone. He had selected roughly 60 alloys for further examination from a book entitled Constitution of Binary Alloys–nitinol being one of them. When he made the ingots for testing, he intentionally dropped one of the cold ones on the floor. Hoping to hear a clear bell-like ring, indicating that the metal had the properties he was hoping for. Instead, it returned a dull thud–similar to dropping a sack of flour on the ground. Worried that the ingot was filled with internal flaws, he dropped one of the ingots that hadn’t cooled yet. This returned a wonderful bell-like ring. However, after the ingot had been cooled in water, it returned a dull, leaden thud, just like the first one. This is the first indication that nitinol had a substantially different double state. Buehler named his alloy nitinol for Nickel-Titanium Naval Ordinance Laboratories. All of this occurred in 1959. However, the shape memory aspect of nitinol wasn’t discovered until a lab meeting in 1961. Buehler had been performing tests to determine the fatigue life of nitinol by bending a strip into an accordion like shape over and over again. His project was brought under review and his technician was demonstrating the fatigue properties to senior officials. During this presentation, one of the officials present heated the nitinol with a lighter, at which point it rapidly straightened out. This, of course, sent ripples throughout the scientific community. This material could take low grade heat and generate mechanical energy! Numerous scientists began experimenting with how to build engines with nitinol that would take low grade energy and transform it into very high grade energy that could be used to do work. This culminated in the Nitinol Heat Engine Conference, hosted by the Naval Surface Weapons Center (previously Naval Ordinance Labs) in 1974. At the Nitinol Heat Engine Conference, the NSWC gathered together the top scientists who had been working on nitinol to discuss what had been done and what still needed to be done to make nitinol heat engines a reality. The presentations from this conference are available in the book Proceedings of the Nitinol Heat Engine Conference. At this point, the activity surrounding nitinol seemed to all but dry up and disappear. Prior to the conference, nitinol researchers were featured on news channels like CNN and BBC. Afterwards, there was little to no attention given to nitinol by major television networks for over twenty years. This led to all kinds of conspiracy theories ranging from nitinol being kept for top secret government experiments to nitinol being an alien technology that was discovered in the Roswell accident. However, the reality is very different. Behind the scenes, material scientists were working hard to figure out HOW nitinol worked.
> In order to fully optimize a nitinol heat engine, it must be understood what happens when nitinol undergoes the shape memory effect. This will be discussed in greater detail in chapter 2. The next time nitinol appeared in public, it wasn’t referred to as nitinol, it was called just plain titanium. Of course, this is a misnomer since nitinol is slightly more nickel than titanium. This new public appearance didn’t even exhibit the shape memory effect as people were so excited about earlier. No, this was completely different and it was marketed under the trade name FlexonÒby the company Marchon Eyewear. Released for public sale in 1995, Flexonâwas unusual in that you could bend it through incredible distortions and it would just snap back to its original shape once you released it. Once Nike began to use it in their Vision line of glasses, athletes everywhere began buying it up. Gone were the days of breaking your glasses on a regular basis just because you lived an active lifestyle. You could sit on them, you could intentionally bend them, you could tackle someone in football, and they would just bounce back. These glasses would forgive those bumps and bangs over and over again–seemingly forever. People who broke their glasses every six months now could go several years on a single frame. The frames were termed ‘superelastic’. Once superelastic nitinol was discovered, it wasn’t long before surgeons began using it as they worked on people. Vascular stents was one of the first applications because the stent could be folded so flat that it could be inserted through the tiniest of holes into the patient’s bloodstream–minimizing recovery time. Once in place, the superelastic nitinol wire could withstand severe deformation and outlast stainless steel by an order of magnitude. To put this in perspective, superelastic nitinol stents were capable of undergoing a 30% deformation with a cycles to failure life expectancy greater than 10,000,000. Stainless steel, on the other hand, could withstand a deformation of just 0.5% with fatigue life of around 1 million cycles.
> Buehler was looking at alloys with two solid states as possible materials for the nose cone. He had selected roughly 60 alloys for further examination from a book entitled Constitution of Binary Alloys–nitinol being one of them. When he made the ingots for testing, he intentionally dropped one of the cold ones on the floor. Hoping to hear a clear bell-like ring, indicating that the metal had the properties he was hoping for. Instead, it returned a dull thud–similar to dropping a sack of flour on the ground. Worried that the ingot was filled with internal flaws, he dropped one of the ingots that hadn’t cooled yet. This returned a wonderful bell-like ring. However, after the ingot had been cooled in water, it returned a dull, leaden thud, just like the first one. This is the first indication that nitinol had a substantially different double state. Buehler named his alloy nitinol for Nickel-Titanium Naval Ordinance Laboratories. All of this occurred in 1959. However, the shape memory aspect of nitinol wasn’t discovered until a lab meeting in 1961. Buehler had been performing tests to determine the fatigue life of nitinol by bending a strip into an accordion like shape over and over again. His project was brought under review and his technician was demonstrating the fatigue properties to senior officials. During this presentation, one of the officials present heated the nitinol with a lighter, at which point it rapidly straightened out. This, of course, sent ripples throughout the scientific community. This material could take low grade heat and generate mechanical energy! Numerous scientists began experimenting with how to build engines with nitinol that would take low grade energy and transform it into very high grade energy that could be used to do work. This culminated in the Nitinol Heat Engine Conference, hosted by the Naval Surface Weapons Center (previously Naval Ordinance Labs) in 1974. At the Nitinol Heat Engine Conference, the NSWC gathered together the top scientists who had been working on nitinol to discuss what had been done and what still needed to be done to make nitinol heat engines a reality. The presentations from this conference are available in the book Proceedings of the Nitinol Heat Engine Conference. At this point, the activity surrounding nitinol seemed to all but dry up and disappear. Prior to the conference, nitinol researchers were featured on news channels like CNN and BBC. Afterwards, there was little to no attention given to nitinol by major television networks for over twenty years. This led to all kinds of conspiracy theories ranging from nitinol being kept for top secret government experiments to nitinol being an alien technology that was discovered in the Roswell accident. However, the reality is very different. Behind the scenes, material scientists were working hard to figure out HOW nitinol worked.
> In order to fully optimize a nitinol heat engine, it must be understood what happens when nitinol undergoes the shape memory effect. This will be discussed in greater detail in chapter 2. The next time nitinol appeared in public, it wasn’t referred to as nitinol, it was called just plain titanium. Of course, this is a misnomer since nitinol is slightly more nickel than titanium. This new public appearance didn’t even exhibit the shape memory effect as people were so excited about earlier. No, this was completely different and it was marketed under the trade name FlexonÒby the company Marchon Eyewear. Released for public sale in 1995, Flexonâwas unusual in that you could bend it through incredible distortions and it would just snap back to its original shape once you released it. Once Nike began to use it in their Vision line of glasses, athletes everywhere began buying it up. Gone were the days of breaking your glasses on a regular basis just because you lived an active lifestyle. You could sit on them, you could intentionally bend them, you could tackle someone in football, and they would just bounce back. These glasses would forgive those bumps and bangs over and over again–seemingly forever. People who broke their glasses every six months now could go several years on a single frame. The frames were termed ‘superelastic’. Once superelastic nitinol was discovered, it wasn’t long before surgeons began using it as they worked on people. Vascular stents was one of the first applications because the stent could be folded so flat that it could be inserted through the tiniest of holes into the patient’s bloodstream–minimizing recovery time. Once in place, the superelastic nitinol wire could withstand severe deformation and outlast stainless steel by an order of magnitude. To put this in perspective, superelastic nitinol stents were capable of undergoing a 30% deformation with a cycles to failure life expectancy greater than 10,000,000. Stainless steel, on the other hand, could withstand a deformation of just 0.5% with fatigue life of around 1 million cycles.
I first saw Nitinol in 1977-78 when I was checking out University of MO, Rolla.* They gave away samples to touring prospective freshman. A short time later there was an article in Omni Magazine about this cool Alloy that no one knew what to do with. Pretty sure there was a prize for good ideas. I still have some patent ideas in a notebook. One might still be viable,although it is mainly for novelty.
I am pretty sure there are many uses to be discovered yet. I suggest everyone here buy a few samples to play with.
*Drank that chance away :) Ended up graduating 16 years later from FAU - Home of the fighting burrowing owls!!
I am pretty sure there are many uses to be discovered yet. I suggest everyone here buy a few samples to play with.
*Drank that chance away :) Ended up graduating 16 years later from FAU - Home of the fighting burrowing owls!!
Why do you think It hasn’t taken off with the clear advantages? Cost? Publicity?
I am not sure what you mean by "it". Are you talking about the parent, or the alloy?
The alloy, sorry. You suggest you even went to extents to conceptualize useful applications but never went past the imagination stage.
Basically I lacked confidence and know how when I envisioned the ideas. One thing I realize now that even good ideas take quite a bit of work. When I get released from the cube farm in a few years, I might try to market one of the ideas.
Nitinol is just an alloy of nickel-titanium 50/50 or slighty differnet ratio. I thought it was more exotic more elements in it but it's quite a simple alloy.
Great! Now, why don't we have nitinol engines everywhere?
1982, not 2015
"no one knows why it happens" What is the state of the art knowledge on this in 2022?
I'm not even positive that was the 'state of the art knowledge' on this even then. I think it was just the news doing news things.
I highly doubt the chemists and physicists who built that precision engine would have been able to do it without a fairly decent understanding of what was actually going on at the materials level, at least something better than 'nobody knows!'.
I highly doubt the chemists and physicists who built that precision engine would have been able to do it without a fairly decent understanding of what was actually going on at the materials level, at least something better than 'nobody knows!'.
there are a lot of unanswered (or poorly, or incorrectly) answered questions in materials science specifically, but science in general. For a recent example, Mould and Medhi recently had a youtube battle about how and why the Mould Effect happens - that is, if you have a string or chain with beads evenly distributed and fairly close together in a container, and start one end "spilling out" of the container, the part of the chain that is changing direction (from up to down) raises above the rim of the container.
I can't remember the youtuber offhand, but there was another question about the "speed of electrons" in a long wire, with actual experimentation to determine the speed. It gets dangerously close to faster than light communication for my tastes so i don't really remember the thesis and arguments offhand, my brain just gets warm.
I can't remember the youtuber offhand, but there was another question about the "speed of electrons" in a long wire, with actual experimentation to determine the speed. It gets dangerously close to faster than light communication for my tastes so i don't really remember the thesis and arguments offhand, my brain just gets warm.
going faster than light is sometimes a possibility!
https://en.wikipedia.org/wiki/Cherenkov_radiation
It is not possible to go faster than light only in an absolute vacuum medium.
I would just like to point out that there's a difference between knowing what something does and knowing why it does what it does.
Had they got the guy from Flextape, everything would've run on nitinol nowadays
are there relationships between the academic knowledge on https://en.wikipedia.org/wiki/Thixotropy and Nitinol property?
this seems remarkably efficient https://youtu.be/3MfTJVAtx6w?t=255
claimed 70Watts here https://youtu.be/3MfTJVAtx6w?t=357
Wonder whatever happened to that. And how they got nitinol to work so well. I've seen nitinol wire, but it's not very efficient. You usually only get a few percent of the heat energy out as mechanical energy.
Efficiency was what I was wondering. But maybe a few percent efficiency is about the best we can do with relatively small temperature differences? I think radio isotope thermal generators are usually only a few percent efficient.
It'd be interesting to try to propel a ship with the temperature differential between air and water.
It'd be interesting to try to propel a ship with the temperature differential between air and water.
iirc the stuff on probes is ~90W of TEM. I know a lot of people say "it's hard to cool stuff in space" but blackbody radiation is a thing. It's all just photons, in the end. the TEM just takes the high energy particles and slows them down enough to be "light" and takes a bit (10%?) of the energy from doing that and uses it to charge batteries. Kind of.
RTGs have other issues as well, they need to radiate all heat on the "cold" side into space, so you're between a rock (high hot-cold temperature difference needed) and a hard place (need high cold temperature to radiate) even before you get to thermo-electric generators being inefficient.
Considering they only talked about applications using low grade heat, I'd say it makes sense iff it's cheap enough, no matter how inefficient because that heat is normally wasted.
Only if you ignore costs.
So you say!
Meanwhile, nitinol actually works via a quantum property, and is sucking energy out of a sister universe.
You don't care because cheap and free, but they do! Doubly so because it sucks power at the easiest parallel source, which are (in their universe) simple copper wire.
Worse, the power stolen is 1000x of times that received, meaning they have been having significant power losses on long power runs.
This means that they have to setup more local generating power, as long power transfer from hydro dams, and clean central sources won't work.
More coal, natural gas, thanks to you! And global warming is far more advanced there.
But you don't care, eh?
When will people learn.
Meanwhile, nitinol actually works via a quantum property, and is sucking energy out of a sister universe.
You don't care because cheap and free, but they do! Doubly so because it sucks power at the easiest parallel source, which are (in their universe) simple copper wire.
Worse, the power stolen is 1000x of times that received, meaning they have been having significant power losses on long power runs.
This means that they have to setup more local generating power, as long power transfer from hydro dams, and clean central sources won't work.
More coal, natural gas, thanks to you! And global warming is far more advanced there.
But you don't care, eh?
When will people learn.
I remember that episode of Stargate Atlantis
The Gods Themselves (1972) by Issac Asimov was perhaps the original inspiration.
Funny story, the setting of part 2 was so different to part 1 that I mistook the book for a collection of novellas until more than half way through.
Funny story, the setting of part 2 was so different to part 1 that I mistook the book for a collection of novellas until more than half way through.
Thanks for the reference. For me it was not Stargate but a recent popular Sci-fi book.
It's called the W dimension.
Oh man, was this the origin story of the rumor that an engine that ran on water was created by and then suppressed by the major car companies?
Amazing, seeing this I feel like I've found bigfoot.
Amazing, seeing this I feel like I've found bigfoot.
You've got to wonder why it never went anywhere. Economics is probably the answer, but it doesn't seem satisfying.
If it can extract useful work from merely warm water, it would seem like the ideal thing to maximise the overall thermal efficiency of a large power plant.
If it can extract useful work from merely warm water, it would seem like the ideal thing to maximise the overall thermal efficiency of a large power plant.
> You've got to wonder why it never went anywhere
material fatigue. basically the nitinol springs/belts/strips eventually breaks.
so it's a high maintenance low-efficiency (hard to scale) system compared to regular steam turbines.
... though of course the latter is in development for ~250 years, so it has a bit of a head start.
material fatigue. basically the nitinol springs/belts/strips eventually breaks.
so it's a high maintenance low-efficiency (hard to scale) system compared to regular steam turbines.
... though of course the latter is in development for ~250 years, so it has a bit of a head start.
It’s not the 250 year head start that gets you. It’s the temperature differential.
Wonder if you could get anywhere revisiting this with modern materials science? Materials have come a really long way in the past 60+ years.
the wikipedia page for nitinol is fascinating!
so it seems like very much part of modern materials science. (and I'd guess bimetals are standard in many heat-related engineering applications, nitinol is just special because of how fast it changes shape, and because it's an alloy not 2 pieces of metal stuck together.)
https://en.wikipedia.org/wiki/Nickel_titanium#Biocompatible_...
so it seems like very much part of modern materials science. (and I'd guess bimetals are standard in many heat-related engineering applications, nitinol is just special because of how fast it changes shape, and because it's an alloy not 2 pieces of metal stuck together.)
https://en.wikipedia.org/wiki/Nickel_titanium#Biocompatible_...
I think the ultimate answer (for all kinds of waste heat recovery, or "heat economizer" technology) is that waste heat streams simply don't contain enough energy to invest in recovering (otherwise, we'd probably deploy ORCs everywhere).
This device seems more useful for generating mechanical motion at the point of use, rather than generating electrical power. I'm envisioning solar and hydro-powered pumping systems that operate in remote environments, like the third engineer interviewed in the video. He proposed that the engine could be used to pump water solely due to the temperature difference between the pumped fluid and the air.
Another interesting thing would be to run the system in reverse to turn mechanical energy into a hot and cold fluid. I haven't thought it through deeply, but it seems superficially similar to elastic band refrigerators[0,1].
[0] https://www.science.org/doi/10.1126/science.aax6182 [1] https://www.science.org/content/article/fridge-made-rubber-b...
This device seems more useful for generating mechanical motion at the point of use, rather than generating electrical power. I'm envisioning solar and hydro-powered pumping systems that operate in remote environments, like the third engineer interviewed in the video. He proposed that the engine could be used to pump water solely due to the temperature difference between the pumped fluid and the air.
Another interesting thing would be to run the system in reverse to turn mechanical energy into a hot and cold fluid. I haven't thought it through deeply, but it seems superficially similar to elastic band refrigerators[0,1].
[0] https://www.science.org/doi/10.1126/science.aax6182 [1] https://www.science.org/content/article/fridge-made-rubber-b...
Nothing can beat the efficiency of the Carnot engine. That's one of the equivalent ways of stating the Second Law of Thermodynamics [1]. Just like you can't create a perpetual motion machine, you can't extract more energy from warm water than a Carnot engine.
And the efficiency of the Carnot engine is 1-T_cold/T_hot, both temperatures expresssed in Kelvin. Room temperature water is 300K (that's by convention, this translates in 27 C or 80 F). Let's say warm water is at 333K (that's more like scalding hot, at 60 C or 140 F). The Carnot engine efficiency is then going to be 1 - 300/333 = 10%.
So, not engine can exceed 10% efficiency when using scalding hot water, for merely warm water it's probably going to be 5% or less.
[1] https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#C...
And the efficiency of the Carnot engine is 1-T_cold/T_hot, both temperatures expresssed in Kelvin. Room temperature water is 300K (that's by convention, this translates in 27 C or 80 F). Let's say warm water is at 333K (that's more like scalding hot, at 60 C or 140 F). The Carnot engine efficiency is then going to be 1 - 300/333 = 10%.
So, not engine can exceed 10% efficiency when using scalding hot water, for merely warm water it's probably going to be 5% or less.
[1] https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#C...
Why bother with a big mechanical contraption like this when you can simply stick the leads of a thermocouple in two cups of water?
Doing so efficiently is the challenge. Thermoelectric generators have very low efficiency of 5-8%. They don't extract a meaningful amount of extra energy.
Seebeck generation is indeed inefficient.... But for low temperature deltas, Carnot efficiency already implies pretty low theoretical efficiency limits.
True, but this means that the ROI for any method of recovering energy from any process' waste heat plunges as the temperature differential drops.
Yeah, it annoys me that so little infrastructure is built with no attempt to make use of the low grade waste heat. Imagine if thermal power plants were built alongside vegetable growing greenhouses etc.
If the thermal plant uses clean fuel (eg: gas fired) the CO2 in the exhaust would be useful for the greenhouse as well.
Many Dutch greenhouses have a CHP power plant, where the heat goes to the greenhouse, the CO2 to the plants and the power to the lamps or to the electricity network. They are swapping the heating to ground heat pumps and the electricity to renewables, so not sure where the CO2 comes from in the future other than of course a higher ambient level.
take the part of the plants that isn't used for anything else and ferment it with yeast. Free CO2. I'm not sure how old this trick is, as i used it a decade and a half ago with 2-3 liter bottles with holes drilled in the caps and a bubbler to remove solids to provide CO2 for a heavily planted aquarium bootstrap.
My theory here is that running all the stems, stalks, and roots that you don't use from stuff like annual food crops through a wood chipper or something should macerate the cell walls enough to allow the yeast to feast, at least.
My theory here is that running all the stems, stalks, and roots that you don't use from stuff like annual food crops through a wood chipper or something should macerate the cell walls enough to allow the yeast to feast, at least.
I think that a Sterling engine would be more efficient.
It was a carburetor that ran on water "I heard about in the 70s" when I first heard that story in probably 2006.
there was a guy in southern oregon 10 or 12 years ago that had a bronco or similar he claimed ran on water. The propane tank on the front seemed suspicious, so i asked, and he said that he first had to convert the gasoline engine to run on propane, and showed me the modifications needed to the spark plugs for that. Then he had an hydrolysis controller mounted in the footwell of the passenger seat up front.
None of what he showed me made sense, so i wrote it off. I know hydrogen power is a thing, i just know that you can't generate enough power with hydrogen to crack water into hydrogen at the rate needed to sustain that, so having all that crap in the vehicle - assuming it worked at all - seemed dangerous, at the very minimum.
Now, i'm sure if you had solar panels - at home[ed.] - and a safe way to compress the hydrogen into small tanks somewhere on the vehicle, you could get a few dozen miles probably fairly safely. And i'm not sure if anyone has patented this yet, but resin/epoxy/plasticize/rubberize the exterior of a carbon fiber tank to store the hydrogen eliminates most of the safety issues, i think.
None of what he showed me made sense, so i wrote it off. I know hydrogen power is a thing, i just know that you can't generate enough power with hydrogen to crack water into hydrogen at the rate needed to sustain that, so having all that crap in the vehicle - assuming it worked at all - seemed dangerous, at the very minimum.
Now, i'm sure if you had solar panels - at home[ed.] - and a safe way to compress the hydrogen into small tanks somewhere on the vehicle, you could get a few dozen miles probably fairly safely. And i'm not sure if anyone has patented this yet, but resin/epoxy/plasticize/rubberize the exterior of a carbon fiber tank to store the hydrogen eliminates most of the safety issues, i think.
At 35 watts, it was more like "microfoot".
The largest unit demonstrated in this video output 35 watts. Not quite 5 megawatts, lest anyone get the wrong idea. That's mentioned in the paper linked in the description.
https://arc.aiaa.org/doi/abs/10.2514/3.48057
https://arc.aiaa.org/doi/abs/10.2514/3.48057
It is paywalled, definitely curious :(
https://sci-hub.hkvisa.net/10.2514/3.48057
> It is found that the Nitinol heat engine
capital costs per unit power generating capacity are approximately $0.15/W, and that the cost of produced
energy for the Nitinol heat engine portion of the power plant is approximately 0.74C/kWh, including operation,
maintenance, Nitinol replacements and the cost of capital for the heat engine. It is concluded that Nitinol power
plants for the conversion of low grade thermal energy may have a significant economical advantage over conventionally fueled power plants.
It seems like it has a huge potential in nuclear plants
It seems like it has a huge potential in nuclear plants
That paper was analysing the system with a temperature difference of 40C (a temperature difference which doesn't allow you to extract energy efficiently anyway). Nuclear power plants at minimum produce steam at about 300C (all the way up to 900C). It doesn't seem like it the paper would particularly support its use for nuclear power. (Basically all plausible uses for this involve using low-grade power. But any system which attempts to do this needs to be really, really cheap compared to conventional systems to be worthwhile).
So back in the 90's a friend and regular attendee at the HBRC club meetings had started a company promoting nitonal wire which they had called "Muscle Wire"[1] they apparently still have a web site. I have a couple of their educational packs and have built their hot/cold water engine which uses a coffee cup with hot water and a coffee cup with cold water to run. It really is quite fun and I ended up building a simple actuator with one of the kits. These days it would be fun to put a cell phone camera on an "antenna stalk" that could be turned and pointed using this stuff.
For most of their applications a current was applied to the wire that would heat it up and cause it to spring out straight, then as it cooled the wire would recover. Not particularly fast actuation but quite controllable.
[1] https://musclewires-com.3dcartstores.com/Muscle-Wires%C2%AE-...
For most of their applications a current was applied to the wire that would heat it up and cause it to spring out straight, then as it cooled the wire would recover. Not particularly fast actuation but quite controllable.
[1] https://musclewires-com.3dcartstores.com/Muscle-Wires%C2%AE-...
I worked at a company in the late 90's that made some of (or first) Braille computers. The braille dots were actuated with Piezo driven at over 200 volts. The piezo compound was proprietary and supposedly the blending process was done by two or three old women in Germany.
Anyhow, we had a retired French physicist (French civilian nuclear program) working on driving braille cells with Nitinol under a SBIR grant. Unfortunately we were not able to get past prototype stage.
The was a very interesting place to work.
Almost forgot the lead- I still have a package of "Muscle wire" that he gave me.
Coincidentally I'm familiar with a company called Dynalloy[1] that appears to have commercialized the same thing on a significant scale with the main application of simplifying mechanisms. Their website says that Muscle Wires and Flexinol are their registered trademarks so there must be a connection?
[1]: https://dynalloy.com/index.php
[1]: https://dynalloy.com/index.php
https://uspto.report/Search/muscle%20wires
i suspect Dynalloy nabbed up the trademark in 2004 after the original owner of muscle wire (1992) failed to keep up the fillings in 2003.
i suspect Dynalloy nabbed up the trademark in 2004 after the original owner of muscle wire (1992) failed to keep up the fillings in 2003.
So superelastic nitinol could be used to fashion a heat pump by placing a wire around a small pulley in the cold reservoir and a large pulley in the hot reservoir.
When the wire is strongly deformed, the phase transition causes it to absorb heat from its surroundings; as a result the area around the small pulley becomes colder.
When this strain is released, the phase transformation is reversed and it will release heat to its environment.
As a result, the cold reservoir gets colder and the hot reservoir gets hotter.
I still wonder why I've never seen even a demonstration prototype of this effect.
When the wire is strongly deformed, the phase transition causes it to absorb heat from its surroundings; as a result the area around the small pulley becomes colder.
When this strain is released, the phase transformation is reversed and it will release heat to its environment.
As a result, the cold reservoir gets colder and the hot reservoir gets hotter.
I still wonder why I've never seen even a demonstration prototype of this effect.
It works with rubber bands too: https://youtu.be/lfmrvxB154w
Reninds me a bit of the stirling engine.
It also operates on heat differences.
And it has also not been used as much as one would have thought possible.
Did anyone else get the impression the newsman was an American faking a continental accent?
The newsman is Kevin Sanders[1] an Australian TV journalist and presenter. He's not particularly well known, but he was a newsreader for GTV 9 (Melbourne) and a presenter for A Current Affair back in the 70s.
His accent is the "broadcast accent" that was cultivated at the time. If you can lay your hands on a copy of Peter Weir's The Year of Living Dangerously[2] you'll hear a young Mel Gibson switch between his normal and a broadcast accent for his scenes in the recording booth.
[1] https://www.imdb.com/name/nm1467242/
[2] https://www.themoviedb.org/movie/11541-the-year-of-living-da...
His accent is the "broadcast accent" that was cultivated at the time. If you can lay your hands on a copy of Peter Weir's The Year of Living Dangerously[2] you'll hear a young Mel Gibson switch between his normal and a broadcast accent for his scenes in the recording booth.
[1] https://www.imdb.com/name/nm1467242/
[2] https://www.themoviedb.org/movie/11541-the-year-of-living-da...
https://www.sourcewatch.org/index.php/Kevin_Sanders
"Sanders' CNN reports on Nitinol, a new metal energy conversion system won the US Engineer's Award for Broadcasting Excellence. His follow-up articles in Science Digest were translated in German and republished in Japanese by Japan Times in their annual selection of the world's best science reports. Sanders is working on a follow-up article and an update documentary for world release on new and startling disclosures on the origins and potential of Nitinol. )...
"Sanders' CNN reports on Nitinol, a new metal energy conversion system won the US Engineer's Award for Broadcasting Excellence. His follow-up articles in Science Digest were translated in German and republished in Japanese by Japan Times in their annual selection of the world's best science reports. Sanders is working on a follow-up article and an update documentary for world release on new and startling disclosures on the origins and potential of Nitinol. )...
Actually he was an American faking a Mid-Atlantic accent (which everybody faked, because it was a made up accent): https://en.wikipedia.org/wiki/Mid-Atlantic_accent
Actually it's an Australian accent.
Mid-Pacific I'd call it.
It's the cultivated Australian accent. It's relatively uncommon and is barely spoken by anyone under the age of 50.
Definitely looks and sounds like a 60/70s ABC (Australian Broadcasting corporation) science segment. Wonder if they still have something similar
Oh like the cultivated non-vulgar Chilean accent, mild version of the accent. Dying breed.
I'm wondering what a continental English accent would be. English as spoken by Northern Europeans as a second language?
No worries, I got your meaning.
No worries, I got your meaning.
I believe this was also covered in the British educational programme named "Look Around You" (https://youtu.be/FBaVwwuErmU).
/s
/s
[deleted]
> The calcic paste is heated in giant ovens to 12,000 BC and left to cool.
This is some great science education!
This is some great science education!
BC was what they used Before Celsius.
"In hot water it springs back with forces of 55 TONS a square inch"...
Hmmm. Is this possible?
Hmmm. Is this possible?
To express that quantity in more familiar units, That's 758 MPa
From Wikipedia article on Nickel-Titanium:
"A great deal of pressure can be produced by preventing the reversion of deformed martensite to austenite—from 35,000 psi (240 MPa) to, in many cases, more than 100,000 psi (690 MPa). One of the reasons that nitinol works so hard to return to its original shape is that it is not just an ordinary metal alloy, but what is known as an intermetallic compound."
So yeah, there or thereabouts.
https://en.m.wikipedia.org/wiki/Nickel_titanium#Mechanism
From Wikipedia article on Nickel-Titanium:
"A great deal of pressure can be produced by preventing the reversion of deformed martensite to austenite—from 35,000 psi (240 MPa) to, in many cases, more than 100,000 psi (690 MPa). One of the reasons that nitinol works so hard to return to its original shape is that it is not just an ordinary metal alloy, but what is known as an intermetallic compound."
So yeah, there or thereabouts.
https://en.m.wikipedia.org/wiki/Nickel_titanium#Mechanism
Perhaps there is a niche application for it in the field of gas compression.
Consider that water itself can exert similarly tremendous pressures with phase changes.
For a statewide school science competition in 1988, I obtained some sample nitinol springs and attempted to build a rotating engine powered by heat differentials. Unfortunately the ones they sent me were very short so I had to make a reciprocating engine instead. I remember being very disappointed at the time, but seeing the prototypes McDonell Douglas made around then leads me to believe I was on the right track.
Good visual overview of nitinol properties here (Action Lab): https://www.youtube.com/watch?v=65r6Ztxi0EQ
Buy some wire of your own: http://www.tinialloy.com/livewire.html
(I worked there quite a while ago)