Nanotube Strength, Bad News for Space Elevators [2019]

in a recent article from nature scientists finally were able to test the strength of nanotubes which is amazing news from the depths of the nanotechnology realm nevertheless it looks like space elevators will remain in the land of science fiction a bit longer but not everything is bad news hello everyone subjects zero here it is the 1970s an arthur c clarke and stuck in his room thinking about the future more like how to make his space novel cooler but anyway at some point he decides to use the idea of space elevator and his novel fountains of paradise he describes a future civilization with a really advanced system of a super-strong cable that could be lowered into earth and used to move objects up and down this was the book the popularizing idea and space elevators became a thing to the scientific community but for many years it was just that a science fiction piece and nothing else it was only in 1993 that many science nerd started to taste the fact that maybe they could actually bring the science fiction idea to life with the discovery of nanotubes a material that would revolutionize everything from that moment on or so they thought cuz it's 2019 and they can't get the thing out of the lab so in his novel which is depicted during the 22nd century he described this system with a magnet structure built on earth and linked through with a cable to a satellite in a geostationary orbit all of this happens at a distance of thirty thirty five thirty five thousand seven hundred eighty six kilometers that's really long cable even thought of this thinks this is possible like thirty five thousand kilometres man you must you must be crazy so if we ignore most of the problems of alien space elevator like the cable and also most of the problems that Earth's atmosphere poses to this idea like atmospheric turbulence Coriolis forces among many others if second or all of that and use some quick physics complex mathematics and the magic of the interwebs so we can skip all of the extremely complex calculation crap and go straight for the answer we will need a cable that can handle at least 63 Giga Pascal's historically the idea was to build a space elevator from ground to space but he quickly faded away as it was too unrealistic since there were no known materials that could withstand its own weight due to the massive structure years later the best concept came from a russian engineer yuri arcs a ton of yuri suggested using a geostationary satellite that would lower the cable Thor's earth and at the same time a counterweight to keep the satellite on the same level at the end of the day the problem with space elevators relies mostly on material strength and that is why nanotubes became so important after its discovery because it's early estimates put this material at some absurd level of strength or to be more precise 300 Giga Pascal nevertheless the pursuit towards cheapest way to get things to space is what keeps this concept alive for instance even with space ax recent advances making travel to space much cheaper you still have to pay around $1400 per kilogram which is much better than just a few years ago when the cost was around twenty thousand dollars per kilogram space elevators would take that cost further down to about 220 dollars per kilogram which in paper looks really good but reality tells a different story both transportation systems have their pros and cons but the main argument against space elevators aside from all its problems is that a spaceship can travel at higher speeds or about 26,000 600 kilometers an hour it takes a little more than an hour to make the distance while the elevator would take days and at the end of the day it's a bit of a trade-off you can either go cheap or fast but judging by how things are getting better on SpaceX side the cost will most likely continue to fall if prices per launch drop to about $600 per kilogram then there will be little to no incentive at all for space elevators and that's not the only bad news nanotubes the one material that was the hope for space elevator enthusiastic not cooperating either so it turns out that nanotube strength has everything to do with its structural atomic configuration in a recent article from Nature a team led by Akira takakuwa sort of confirmed one of the problems with the structure of nanotubes and why scientists weren't able to produce nanotube structures that reach the max theorized strength like I mentioned before good news for ongoing research but very bad news for space elevators and this is not the first time the nanotube strength has been pushed back in its earlier ears it was thought that the strength was close to 300 Giga Pascal's but a few years later it was lowered to in between 100 and 200 GPA these numbers are nothing more than a theory based on atomic bond strength to which they extrapolated and got the 300 GPA at first over the years scientific equipment got more precise eventually leading to a revision of earlier predictions nevertheless anything in the GPA level is still really strong a quick comparison with other materials show how much bigger the strength of nanotubes is in comparison notice that even the lowest strength to weight ratio yielded by lab tests is much higher nanotubes weakest configuration is still 10 times stronger than Kevlar but this problem of extreme strength variation can be easily attributed to the methods used to synthesize the tubes this is a common problem in nanotechnology where you can only really go for either one of the two things quality or quantity something that I have addressed previously in many of my videos nanotubes are nothing more than cylindrical ear old graphene sheets yes guys I do read your comments for a few years now they have been theorized to be an outstanding material in terms of strength to weight ratio and it is because of that that the whole idea of space elevators could actually come true in the near future if only they could prove that nanotubes we're as strong as they were thought out to be this is important because this three if necessary to get anything close to space elevator going like I mentioned before needs to be at least 63 GPA but what is it that they figured it out well it turns out that there are three configurations that you can make nanotubes in and that is what they tested all of the three configurations yields completely different strength values which is okay but the problem is that in some cases that strength is well below the 633 GPA while other times it barely passes that however it never even gets close to the predicted values of 100 to 200 GPA this is a problem attributed to the production techniques used for instance in this experiment they used a method of chemical vapor deposition developed back in 2002 using low-temperature with alcohol as the carbon source keep in mind that there are many types of CVD technology and this is just one of them the technique discussed here was developed with a low cost and low temperature production in mind not high quality nonetheless with recent advancements it can yield high quality tools with only a few tweaks to synthesize the tubes they used iron acetate and cobalt acetate dissolve in ethanol which are the metal catalyst for the reaction they are then introduced into a furnace that heats everything up to a temperature at maxed 600 degrees Celsius and the reaction takes place with alcohol vapor being injected into the chamber this technique is way more complex than I'm describing here so if you're interested in making nanotubes yourself or would like to just read the paper for fun the link is available in the description below they analyzed the tubes using scanning electron microscopes and transmission electron microscopes to verify the structure of the nanotubes created it is a dismal they are able to identify the structural configuration of the tubes one point I must stress is that no scientist knows for sure why there is so much variability in terms of tensile strength but apparently the arrangement of the structure may play a role worse yet up to now there were no tests conducted about this which shocked me first and makes everything indeed science fiction to highlight what I'm talking about we need to understand how hexagon patterns can be shifted around to create alternative structural patterns let's take a look at a graphene sheet if we roll it the way it is shown on the screen you will get the most famous nanotube pattern that most likely you have seen everywhere but if you change the angle of the hexagons just so slightly magic happens just by changing the angle 15 to 30 degrees you can completely change the entire structure and strength of the nanotube keep this in mind because it will become important later once synthesized they test each individual nanotube strength by using a micro electromechanical system which basically pulls the tubes apart while measuring its strength and what they found was staggering they managed to test 16 variations of structures like the ones I defined earlier it showed that the strength is deeply dependent on the angle and diameter of the tool these tests yielded results ranging in between 22 and 66 GPA which can be attributed to problems within the structure of the tubes the weakest tubes were in the diameter range of 1.5 to 2 nanometers plus while the armchair configuration yield at the highest strength of more than or equal to 70 GPA Cairo showed the lowest strength or less than 25 GPA now keep in mind that these tubes were not perfect hence why we won't see the strength near 100 GPA until they managed to make defect free tubes the ultimate conclusion is that the strength of nanotubes is a linear relationship in between the Kairo angle diameter of the tube and size of the defect basically what this means is that for each angle there is a maximum stress that the tube can take a more armchair like configuration should yield the strongest configure however if there are any defects on the tube it will have an impact on the structure that is dependent on the diameter the smaller the diameter the more any defect impacts the overall strength the opposite is also true the bigger the less but if the diameter gets too big then the structure also loses strength so the sweet spot we could say for now is that the armchair configuration with a diameter less than 1.5 nanometer is optimal ultimately what this means is that there is an optimal structural configuration to be targeted and an intrinsic need to further ameliorate current methods of production to achieve this or else we will never have space elevators but then again space axis about to send space elevators back to the science-fiction realm anyway if they keep up with the good work that they're doing alright folks that's it we're done here [Music]

Channel: Subject Zero Science

Views: 152,114

Rating: 4.864491 out of 5

Keywords: carbon nanotube, carbon nanotubes, space elevator, subject zero science, space elevator kurzgesagt, space elevator documentary, carbon nanotubes no mans sky, carbon nanotubes solar cell, graphene technology, graphene strength test, graphene production, graphene battery, graphene sheet, space station, space travel, graphene processor, how to make graphene, thorium reactor, battery technology, elon musk motivation

Id: u7tjYISFNs4

Length: 11min 36sec (696 seconds)

Published: Sat Nov 09 2019

Reddit Comments

[u/qwiglydee]

Is all the text, like that on "flat slides" also added in Blender?

[u/BhargavDronamraju]

Cool Video! It says "animated in Eevee" does that mean you didn't use a seperate NLE altogether since the entire video is animated? This got me thinking on just how much 2D NLE editing and compositing can be done in the viewport alone. Like backgroud Blur effects could be done by simply changing DOF settings. Fade ins/outs could be created with a Black plane parented to camera that has it's alpha mask level animated. Any video could be an animated texture. This could be an interesting direction for non-destructive workflow and minimal render iterations for simple composites. There may be a new way to combine the compositing and 3D animation as one continuum rather than separate artistic operations. I would call this Deep Compositing Continuum.