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Non-Newtonian or shear thickening fluids can turn solid when pressure is applied hard enough and quick enough. Oobleck is a mix of cornflour and water in just the right proportions, forming such a liquid. You can run across a pool of Oobleck, apparently, because your feet it hard enough and fast enough to form a solid layer, but walk and you are sunk. These materials have been explored for use in body armour, but while they may stop bullets, the weakeness is the slow knife still penetrates, as they remain liquid. We have long since been wondering if we can exploit these peculiar properties of Oobleck for rock breaking in controlled ways. We performed a series of tests with detonation cord in drill holes filled either with water or oobleck. These early results indicate that shear thickening fluids may have pivotal roles in controlled, efficient blasting, and certainly it would appear that the blast protecting nature of Oobleck is significant. I have included our videos with the observed results here.

Extreme events such as impacts, ballistics, explosions and blasts, which occur at very high pressures, and very high speeds, is difficult because of the highly specialized diagnotics, really involved physics and the computational methods which are generally very niche. The one major advance in recent years is the advent and ever increasing availability of very high frame rate and high spatial resolution cameras in combination with the ability to store and process rapidly the very large amount of data generated, together with the development of batch image processing techniques as well as free software such as imagemagick, gimp, ifranview and many, many others. This allows us to auto-analyze the data which is in the form of video - a sequence of images, run it through many different "filters" and "algorithms" rapidly to elucidate different features which are not apparent to the human eye. Yet, there are still many applications for which these readily available capabilities have not been fully exploited - which means there is all to play for and still much to learn from applying these technologies in areas of extreme science. But as the digital camera technologies are still developing at a pace, as is computational science and power, including graphics etc, I do belieive that science in this area needs to constantly evolve with the times - we need to look again and again at what we might have videod ten years ago, or maybe even a year ago, because each time, the improvements are likely to reveal more new things we missed before. If I may I would like to show just one small example of what this combination of technology and software developments can now do. This is a very high speed video of detonation cord exploding - to give you some idea the detonation is moving at nearly 8 km/s. It is only a frame rate which might have been unbelievable a few years ago, which makes this possible at all. The link and reference to the original video can be found in the you tube description for this. What we did was to transform it by running it through very many "change detection" algorithms to try and highlight something we saw very faintly in the original - the crossing of the air shocks driven out after the cord has detonated [because this has important learning outcomes for blasting engineers in terms of visualizing the shock wave processes]. This video shows the results for three particular attempts, the third one shows up what the eye cannot see in the video very clearly, note the air shocks propagating out left and right as white lines.

A scientist seeks the truth, while an engineer seeks the solution to problems?

To me this is quite clear and I always like to use wikipedia's definition to make the distinction clear "An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics, and ingenuity to develop solutions for technical, societal and commercial problems. Engineers design materials, structures, and systems while considering the limitations imposed by practicality, regulation, safety, and cost."

In developing our "science outreach" You Tube Channel programming, one of the things that struck me was that the interactive elements allow delivery of "software like" videos applications. By which I mean it is possible to pre-compute a whole bunch of solutions to different problems using scientific software/programs and then allow viewers to make their way through choices/menus to get down to different levels of "granuality" of different parameters. Here is an extremely simple example, which was created to help blasting engineers visualize how changing different things effect the shock waves in the rock Certainly one feels the technical merit for science education could be quite high.

I would love to see bullets and projectiles fired in to it, videod with high frame rate. I wonder how it spalls? Is dark choc much more brittle than white choc? Is Belgian Chocolate [real chococlate] completely different to American Candy cocoa solids [faux-choccy]? What an interesting piece of materials science.

No you cannot protect mathematical models or physics equations. Computer code is automatically protected by copyright, but someone else can write a similar code from scratch for themselves without asking permission to use your equations. If you want computer code to be protected then keep the source code secret - which means never ever letting near a networked computer. As Timo says, patenting and copyright are completely different animals. You can only patent an idea which is not in the public domain. I'm afraid if you have told someone about your idea without first entering a confidentiality agreement with that person, that can count as public domain. What you have to bear in mind is that even if you patent something (i) the patent - and hence the idea - is in then available for people to look at publicly. By protecting ideas by patents you also expose them. (ii) the patent DOES NOT mean people can't copy your idea - it means you have legal means to try and stop them. The cost of patenting is not in the patent but in the cost of pursuing the patent breakers. James Dyson, the inventor of the Dyson vacuum cleaner, nearly went bankrupt when he first started protecting the idea around the world.

But in my everyday [not every day!] experience, chocolate is solid and undergoes brittle failures and can be fragmented too. Does the addition of saliva have something to do with the all important "mouth feel" transition too? What if its got nuts in? Nightmare for modellers...

Oooh, lets have this discussion. I too can generally write these equations down from first principles material frame description and can write fully hyperelastic viscoplastic [properly rate dependent] codes even for the extreme dynamic limit of true shock physics [proof: ] and I thought rock was rock hard... but I just don't have a clue how to do this choccy question. Please do inform us how to contend with solid-liquid transitions. oh, did not realize the aside link would appear like that in my post!

Yes realized was drawing parallels too closely in attempt to put things in familiar terms. Source for black powder info is internet - might want to double check. Some commercial motors are AP. With black powder ones you have to be a little careful as if you damage motor you get cracks in the compressed powder I believe. This makes burn rate quicker and pressures higher than one might expect. Having said that model rocketry is very safe hobby according to statistics. It made the breakage different. In all those shots, the cartridges are exactly the same, its other things in the hole which makes difference [apart from cases where there are two cartridges per block - 4,7,8,11 if i recall]. No, these plugs are brand new design - we are going to put them to the test soon.

No. Estes engines are black powder if I recall compressed into a solid motor with a hole down the middle. Not right for this job. Please don't try this at home folks whatever you do!!! The rock breaking cartridges are special, as are the igniters as are the other bits and bobs. This does not mean makeshift things are safe - they are not and we witnessed some hazards in a quarry where they were using loose black powder just the other day. Some of the science is in the chemistry or formulation of these new mixture which is designed for safety and performance factors. Not its not the igniter ejecting its part of the "confinement engine".

Cheaper - potentially, because we need barely any to break the rock. Those concrete cylinders had charges of 4g. A spoonful. Safer - YES. These cartridges do not explode until they are confined. They cannot go bang even in a fire unless they are completely confined by something. They are so safe they can be sent by courier. Imagine doing that with explosives. But also because the pressures they generate are more commensurate with the rock strengths they do no produce the excessive noise, vibration of dust that high explosives do. Commercial explosives produce pressures of a few gigapascals - thats 100,000 atmospheres. The tensile strength of rock is in the 10 megapascal range. These are now in use underground mining, quarrying and concrete removal as well as other applications.

***ADVISORY: these rock breaking propellants are not the same as what you put in model rockets or otherwise. You must not try this at home**** This post is about some potentially high impact technologies under development, which have lead to some really interesting scientific advances along the way. There is little peer review work I can offer, due to this being truly industry and market driven R&D. However, there is plenty of video evidence from around the world and I have made a playlist here https://www.youtube.com/playlist?list=PLXlGYIt2uJKP4XoLQ1GWlrZJLm4w9_yxx The 2nd and 3rd of these intriguing articles we were involved with, but the rest are completely independent. The scientific challenge is to perfect the next generation of "breaking engines" for rock blasting and demolition, using similar classes of materials to rocket fuels ("propellants") to break, instead of high explosives. While in rockets, a propellant's main function is provide maximum thrust and controlling the chamber pressure is essential. here the challenge is to keep the **specially designed*** propellant confined in the drill hole for as long as possible. In other words we want to produce maximum pressure, without the exhaust gases venting at all. The results can be astonishing. I hope you find these videos as fascinating and thought provoking as I do.