studiot

Yes I'm quite sure. We are talking about Gaussian curvature here; Gaussian curvature is intrinsic. Here is a much better article than Wiki, with lots of explanatory references and examples. https://www.maths.ox.ac.uk/about-us/departmental-art/theory/differential-geometry Note that curvature is not the only property with extrinsic /intrinsic classification. Intrinsic Property Def: Relating only to the bearer of the property, not to the space in which it is embedded. Extrinsic Property Def: Relating only to the space in which it is embedded, not to the bearer of the property. Chirality or handedness is one such, which also shows how something (a plane in the example) can have one property extrinsic, but not another. The 'intrisic equations' of a plane curve can distinguish one curve from another. But they cannot distinguish chirality for instance for a left and right handed spirals. Chirality is a property of the space (Effectively because the direction of one of the axes is reversed).

To be honest you are overthinking this. Configuration is a geometrical term which (in this case) means the disposition in space of all the parts of a system. Potential energy is that energy which will (in general) change when you change the disposition i.e. move the parts of a sytem to new locations relative to each other. The exceptions are systems such as a body orbiting the Earth at constant distance from the centre, and multipart systems where some parts gain PE in the reconfiguration, and some loose PE with a net overall zero change to PE. The concept was introduced in connection with Mechanical Energy, and is best understood this way. The principle of conservation of Mechanical energy states The total mechanical energy of an isolated mechanical system is constant. Mechanical energy can be divided into Potential Energy and Kinetic Energy, so this means that their sum is constant. Consider a heavy pendulum swinging from a fixed point above the Earth in the Earth's gravitational field. At the bottom of its swing it has some KE as it sweeps past the low point and some PE due to its height above the centre of the Earth. At the top of its swing it stops completely so has zero KE. So what has happened to that KE? Well once the bob has passed its low point it rises to a greater and greater distance from the centre of the Earth so its PE increases and, in fact at the high point, all its energy is now PE. Once it has passed the high point it falls again and gains KE at the expense of PE. Does this help?

Where exactly did I say it was? Please do not imply something I did not say, particularly if you are going to be rude about it.

In speculations, the onus is entirely upon the promoter (you in this case). So I don't have to prove anything. However since my objective is to save you a great deal of fuitile and fruitless work (which is why I have been so plain and blunt). Fluid Mechanics is quite different from Solid Mechanics. For instance it is impossible to apply a force of any description to a fluid. Think what happens if you drop a 100kg cannonball into a tank of water. Does it apply 1000N to the water? Of course not. It just falls through the water. So let us look at a very simple pipe system. A pipe with plugs at A and B containing a fluid. Starting (as you have done) assuming there is zero fluid friction, what happens if you push with any force whatsoever as shown in the diagram? Do you think you develop any pressure within the fluid? The answer is no you don't You will find, if you try this experiment, that you simply displace plug A sideways until you stop pushing. You will also find that you cannot apply a specific force F of say 10, 100 or 1000 N. (in practice all you will need is enough push to overcome the friction holding the plugs in place, but you cannot increase the push beyond that.) Can you now see what is missing from your analysis? There is nothing pushing back at A to overcome. If you are as good at mechancis as you claim, draw a free body diagram of the fluid. That would be the correct way to analyse the situation.

No that's what this forum is for. Remember that PC is a universal constant. So if you change it you change the result of any equation or result that you apply it to, not only photons. Nor can you only change it for some things and not others. However photons have zero mass, so their mass would not change, only their energy as you deduced. You can also deduce the effect on energy by noting the units of PC, as I said. How did you get on with that bit? You probably have not yet come across 'dimensional analysis' - it is a really handy tool.

I recomment you stick with your 3D sphere analogy. It is much easier to get your head around. Further please note it is impossible to map a sphere onto a plane so beware of 'projection'. There are two types of 'higher dimensional' curvature. Intrinsic curvature which is the type I was describing. This has direct effects, such as spherical excess, within the lower dimension. Any being of the lower dimension would be able to detect these effects, just as surveyors and navigators detect spherical excess on the surface of the Earth. The other type is called extrinsic curvature and can't be detected by any means available to the lower dimensional being. Have you understood spherical excess or do you need more help with it?

The being would be able to determine the fact that he was on a sphere, and the size of it, by measuring spherical excess. http://mathworld.wolfram.com/SphericalExcess.html

I disagree with you posted mathematics for the output pressures. The full Pascal pressure can only be developed if you apply suitable opposing forces against the output piston. Otherwise there is no reason for the stated increase in pressures. And I am reporting your lack of reply as against the rules of this forum.

Were you going to address my question?

The first thing to know about PC is that there are two versions. Commonly called h and hbar, which incorporates a factor of 2Pi. (you can see about this in my link) hbar is used in most modern QM treatments. Then look at the units of PC and ask yourself what fundamental physical units or dimensions doe it depend upon or affect. (again look in the link). Ask here if you don't know what 'dimensions' mean in Physics - mass (M) length (L) and time (T) etc, or have more detailed questions. Finally take a gander at Planck units. This should give you enough material for a rip roaring tale of Physics. https://en.wikipedia.org/wiki/Planck_units Go for it.

Thank you for coming back to tell us what happened. I'm so glad how well it turned out for you. +1 Please give us more notice next time.

Very quickly this morning, Some things to realise about what is shown in common textbooks. Textbooks tend to consider the 'equilibrium' contact and how it is achieved, usually using energy diagrams. This is the position in figures 1 to 4 in your link. But there will be zero current flowing in this situation, because there is no complete circuit established. Your link is good because it has a figure 5 which is not an energy level diagram but a voltage / current plot whic shows a complete circuit as well as ohmic (5b) and Schottky action (5a). Working out how the current is carried in a complete circuit will help you a lot. Especially as there is a big difference between P type and N type semiconductors. I don't have time to draw any diagrams until later.

Not really forces, no, although they may be present and indirectly contributory. consider a (small) tank containing a hydrogen and oxygen mixture. This has potential energy you can release by igniting the hydrogen, but there are no forces between the particles whilst the tank sits there. Well there's translational energy (often called kinetic energy) vibrational energy rotational energy Heat energy (which is really a mixture of the above three) Then there's nuclear binding energy and some more esoteric types. Sort of but it get very complicated very quicky when you start talking about the tensors in general relativity that contribute to this.

Just use the conventional terminology, like everybody else. Then there is no confusion. A Schottky junction is the same as a metal-semiconductor junction. The emphasis is on the word junction the other words distinguish it from a semiconductor junction device. The other alternative is called an ohmic contact and does not include the word junction. Now that we have got that cleared up how about being more specific with your actual question that a link to an 11 page pdf? (Glancing through the document suggests it is worth reading, )

That's a fair question. Presumably your video included some description of a ball of gas being made of molecules flying around inside the ball and constantly bumping into each other? The average speed of the molecules tells us (determines) the temperature of the ball. But like all averages, some molecular speeds will be faster than this average and some will be slower. Molecules that collide head on get slower and molecules that collide sideways can get faster. So molecules are always changing their speed. The faster a molecule is going the more energy it has So the higher the temperature of the ball the higher the average speed. In order to initiate fusion the impact has to involve a threshold or minimum amount of energy. So this means a minimum speed of impact (head on) between two fast molecules. OK so that's how fusion can start, what does that mean for fusion? Well two things. The bigger the ball, the more chance there is of a series of collisions adding up to some fast enough molecules to fuse on collision. Or the higher the temperature of the ball the fewer the number of suitable collisions required to speed up a few molecules to fusion speed. The Sun is a very large ball of gas so it can initiate fusion at a lower temperature than a smaller ball on Earth or elsewhere. So either we make a ball of gas as large as the Sun (impractical) or we work at a higher temperature. Incidentally, the problem with fusion is not reaching the necessary temperatures, that has been done. It is containing the high temperature plasma (the gas become a plasma at high enough temperatures, but that is another story) long enough to keep the fusion process going. It is also interesting that the Sun is largely made of Hydrogen, whiklst the molten sore of the Earth is a mixture of ferrous metals and is, in fact, hotter than the Sun (at least at the surface). But there is no fusion in the Earth's core, because hydrogen is a lot easier to fuse than 'heavier' elements. Does this help.

I know you have ignored the law of conservation of mechanical energy by introducing friction and some other magic force called 'pression' and then failed to account for their energies in your calculations. The hydraulic systems you have drawn cannot act in the way you describe. You need to know enough Mechanics to understand what they will actually do before putting numbers to things.

So tell me again why the first sentence in your initial post was not wrong or rephrase it so I can understand what you actually mean please.

This is complete and utter nonsense in that it utterly ignores the laws of Mechanics. I asked a simple question (Hint the sentence ending in a question mark). The Laws of ScienceForums expect you to answer.

I don't find it at all suprising that prior to the rise of Stark and the 'Aryan Physics' movement, (1933) when many prominent Jewish academics were replaced by non Jews in Germany that pressure groups had existed for a substantial number of years. Such activity has many precedents in history and even today. Some of this is bloodthirsty and some more 'civilised'. For instance The Protestants burned Bruno at the stake. The Catholics threatened and perhaps tortured Galileo The French Revolution executed Lavoisier whilst Fourier flourished. Both the Tsarists and the Soviets condemned scientists to the gulags (sharashka). All of these were carried out by authoritarian regimes in the height of their powers. But that poser but did not come overnight - it took years in the developing. I also said more 'civilised' The US Presidency clears out most of the heads of departments with an outgoing President, to be replaced by those in favour with the incoming, regardless of how good they were in office. I suppose you couldc all this more civilised because heads no longer roll as they used to in ancient civilisations and past european clearouts.

Here endeth the lesson for today read by the Cookie Monster.

Pauli exclusion Principle https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecules/Electronic_Configurations/Pauli_Exclusion_Principle and also Hund's Rules https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecules/Electronic_Configurations/Hund's_Rules

A Schottky barrier is high resistance in one direction and low resistance in the other. An ohmic contact is low (ish) resistance in both directions. They are not the same. Read your own reference again thoroughly. Right at the beginning, it says the exact opposite of this Either a Sckottky barrier or an ohmic contact. For your further information the Schottky barrier is formed when the metal is bonded directly to a block of intriniscally N or P type material. This effect occurs with different metals for either N or P, but not both. So bonding aluminium to N type gold to P type creates the Schottky barrier. Doing it the other way round does not. Bonding the metal to a part of the block of N or P type material which is heavily doped to be even more N or P type creates an ohmic contact. Whilst you are digesting this and asking further questions, I will read the rest of your reference.

KE weapons are amongst the oldest ones we have. Fist, lance, spear, arrow, club, quarrel, ram, cannonball, bullet..........................................

You now have a thread with two pages of nonsense and wasted effort. If you put one tenth the effort of making these diagrams into learning some basic mechanics you would be much further forwards. Properly learning this is urgent for anyone who offers the statement "Blackball 1 already have a force of 60N before striking the piston pusher." Do you know what force is and would you be willing to learn if someone told you?

No one is trolling you. Of course there was a concept of pure vacuum pre 1930. The constant we are talking about was introduced by Coulomb in 1785, although he used different units from modern SI ones, they were definitely not zero.