paulsutton

Sorry for the delay in this. The book I have is : Structural Mechanics Second Edition Ray Hulse & Jack Cain ISBN: 978-0-335-80457-5 palgrave.com

Yes, Nature does have a canny ability to throw a spanner in the works of current thinking, Even the JWST is re writing our understanding of the universe early history, so as you said nature has many things that don't fit. Once we reach the moon, we will probably end up re-writing everything on stress based on what we learn in micro gravity on the moon. Different environment will throw up more problems, just that the stakes will be much higher i guess, as we can't evacuate a moon base. As we are talking about materials and stresses, what do people make of this?77 'It's crazy' - villagers mystified as river dramatically changes course https://www.bbc.co.uk/news/articles/cqxlv7x1527o Would there be a connection, it does look like human intervention by land owners may have had unexpected consequences.

I found a book in a charity shop on Structural Mechanics which seems to cover some (or may be all) the topics @studiot is covering so I I will give that a read too.

I was thinking that, given that 1 mole of a substance still has the same number of atoms, e,g 1 gram of Hydrogen and 238 grams of Uranium would still have 6.022 x 10^23 atoms. So they may calculate based on that, and as you said infer the 1/2 life. Maybe that is a question for another thread.

That is pretty cool, I wonder what he would think about the fact that his experiment is still going after nearly 100 years, Then again look at the 1/2 life of some radioactive isotopes, some take seconds others take days, months or even years.

Is this why people are advised to lie on their back and float in water, if the get in trouble, as it increases the surface area and buoyancy due to the upward forces? Interesting geological / geochemistry differences given Devon and Somerset are next to each other, how do they contrast with Dorset ?

Yes, but isn't excusive or written as XOR as opposed to OR. for an OR gate?

Just found this course on Futurelearn, which may give some insight into your question https://www.futurelearn.com/courses/justice-fundamental-rights-and-artificial-intelligence Paul

I will try and do some more digging in terms of haemoglobin. In terms of what was mentioned before near the coast | was more thinking of cars rusting due to salt (or rather sea) water ( even though I think it is more corrosion) rather than silver tarnishing, sorry I need to be more clear on things. Re Haemoglobin https://www.tandfonline.com/doi/pdf/10.1179/135100003225002817 Seems to explain the process, with oxygen and haemoglobin, this is a little above me, but I do understand what a REDOX (Reduction and Oxidation) where Reduction is gaining electrons and oxidation loses electrons). Seems quite a complex set of processes going on with this.

Agreed, however it doesn't stop what ever metal you are using reacting with the environment, chrome for example will tarnish, silver does over time, i think more so in salty environments such as near the coast. Am I right in thinking Oxidation is still transfer of electrons (loss) even if this is iron or hemoglobin to oxyhemoglobin in blood. Paul

I am not sure, Mastodon has a feature where if you upload a flyer for example, the alt text generator can take the image and try and extract the text elements (it has mixed results),, So I think the first stage may be just OCR and see what it comes up with, If you can manually edit a few words, that may help, perhaps then run through a spell / grammar check or similar and see what comes from that. If you want the output to be just readable, you don't want AI or anything inserting new words that could easily alter the meaning of the original text. It probably requires manual intervention either way,

So to reply to @studiot I have tried to look up some of the terms / ideas presented above and put my thoughts / interpretations below along with references to where I got the explanation from. * Archimedes Principle. [Archimedes Principle.](https://www.britannica.com/science/Archimedes-principle) covers the laws of buoyancy and states that " that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force,"* [1] * Convert [Newtons to grams](https://www.convertunits.com/from/newton/to/gram) * Terzaghi introduced the notion of 'effective stress'. [2] If we apply this to sand then the sand, if placed in a heap (with a slope) needs to have enough strength to stop that slope moving (or as per [2]_ slumping. [2]. Comment, this makes sense, if you're on a beach and try and take the top layer of dry sand and pile this up, it is harder to create a pile, where as digging deeper to the sand that has more firmness (due to water content) can be dug out and piled up, the same goes for making sandcastles, they are likely to stand on their own if the sand is damp and sticks together, nevertheless if you use very wet sand you end up with a similar situation as with the dry sand, it won't keep it's shape. * Contact force, [3] These are forces between two objects * Contact stress [4] I don't fully understand this from reading the source I found. (Don't understand dwell pressure) * Direct (also called normal) force and stress [5] From the source (wikipedia) "In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to tensile stress and may undergo elongation. An object being pushed together, such as a crumpled sponge, is subject to compressive stress and may undergo shortening" So I get this, so if I pull something it becomes longer, and I guess weaker as it becomes more elongated, going the other way the stress of compression can also impact. * Tangential or shear force and shear stress ( not indirect or abnormal ), [6] I think I get the principle behind this, so two objects moving against each other. I guess another example is to rip sheet of paper, by holding and pulling in opposite directions causing the paper to be pulled (ripped) apart. Would I be right in thinking that if I try and bolt two materials together that are held in tension, the bolt must be strong enough (tensile strength) to resist the two forces pulling apart that the bolt is holding together. References 1.[Archimedes Principle.](https://www.britannica.com/science/Archimedes-principle) 2 [33.2: Terzaghi's Effective Stress Principle](https://eng.libretexts.org/Bookshelves/Materials_Science/TLP_Library_I/33%3A_Granular_Materials/33.2%3A_Terzaghi's_Effective_Stress_Principle) 3 [Contact force](https://en.wikipedia.org/wiki/Contact_force) 4 [Contact Stress at the Beginning of Demolding[(https://www.sciencedirect.com/topics/engineering/contact-stress) 5 [Stress (mechanics)](https://en.wikipedia.org/wiki/Stress_(mechanics)) - This may not be the correct reference 6 [Shear forces](https://en.wikipedia.org/wiki/Shear_force) Hope this helps Paul

I am not sure what some of these mean exactly, so alongside any explanation here, I am going to do my own digging and research them ( it is kinda expected here after all) it will be interesting to compare findings as they should be the same or very similar explanations ( if I find the right sources). Paul

I was thinking this, as we can pour liquids and also pour a container of Sodium Chloride into a beaker, despite the latter being made of small (granular) particles. With landslides, I usually think of these as being mostly caused by rain fall for example causing the ground to I guess to lose cohesion and move down a hillside or cliff face. We have had this in Dorset, https://www.bbc.co.uk/news/uk-england-dorset-68332305 However, I think these are caused by the area being very dry and collapsing (maybe weight related), the ground also cracks in very dry weather, ( probably the correct term is fissure ) Avalanches (IIRC) are moving snow but are these on top of a pocket of air or is there a sort of air pocket in front of the moving snow. Does the shape of the particles also play a part, I think Salt (NaCl) is cuboid (or at least looking at the structure diagrams it is) graphite is layers so they slide, compared to diamond which is more ridged), Sand appears to be trangular or perhaps pyramid shaped https://chem.libretexts.org/Courses/Honolulu_Community_College/CHEM_100%3A_Chemistry_and_Society/14%3A_Earth/14.02%3A_Silicates_and_the_Shapes_of_Things So maybe this is also a factor in how easy something will move around (even if sold). Paul

This is really important as you said with climate change and changes to agricultural methods we know that insect and bee populations has been seriously reduced hopefully this can be rolled out to reverse some of the damage. Important as we need bees to help grow crops etc. It will be interesting if this can be turned in to an off the shelf product, people could buy at garden centres for example, we know the importance of allowing parts of a garden to grow wild, or plant specific flowers etc to help bees etc, This could give that a boost. Paul