studiot

Thank you that will give us something to work on.

No. Please read my point number 1 again. It specifically refers to the article presented by the OP. Why do do think I made it No. 1 ? Let us discuss what that article actually stated. I cannot divine what the authors may have meant to say, only what they did say. Furthermore I expect, though I am not cetain, that that article will have undergone some sort of peer review process, given its source.

A lot of different possible 'experiments' have been suggested and you have rushed off once or twice to start on some. I seriously suggest you do some collecting and collating before starting any more and plan a course of action. Otherwise you will be doing a lot of tail chasing and probably unneccessary work.

I.m not arguing anything at the moment. I am trying to keep my posts short, especially as you keep avoifing the pertinent questions I ask in each one. In response to your question I am not arguing anything I am seeking factual information about the numbers you are claiming. It is quite insulting that you only bother to reply after I remind you twice this last time.

Yo, Moon that looks interesting. +1 Where I live we grow a lot of 'withies' . There are traditional willow slips before they get to tree status and are still bendy. We are now somewhat famous for the Willow Cathedral, which is constructed by intertwining bendy willow in the manner you describe. I must try to look out a picture.

Pity, just when I though we starting to get on well.

A small spanner here. A large part of a living tree is dead. If the outer layers of the tree remain intact, the heartwood will not decay, even though it is dead and retired sapwood. Some believe heartwood must be the most important part of the tree due to the fact that it is called “heart”. However, the name just refers to the central position of the heartwood in the tree. 27 Sept 2019

If so then why did you not quote the entire passage I posted when you made the strange sarky comment as a 'question' ? The entire passage was predicated entirely upon placing an incontestible accident of fact in antithesis to what we have been asked to judge as being excessive political correctness. Or perhaps the originators of the paper, speaking American English, would have failed an exam set in English English and I did not understand their use of the three letter word all. So perhaps you would be kind enough to explain it to me so I don't get it wrong in the future and tar all americans with the brush of misunderstanding.

Well well well, I pause to have lunch and go to Tescos and you have stopped talking to me again.

I thought so. You said you are an engine mechanic - a very respectable trade I know such people who have many innate skils I don't possess. They find it easy to for instance dissemble, fix and reassemble aBorg-Warner auto box whilst I know from personal experience of much simpler mechanics that I would struggle for days and probably not succeed with a B-W. However you anser brings us to appreciating the difference between power and energy. I have assumed you know this. Total energy (you have a total energy meter ?) used to keep the waterbath temperature constant for 15 minutes. Do you think 15 minutes is enough ? I don't. So over a longer period you can measure the energy to maintain that waterbath temperature. So what ? How do you know what proportion of that input actually goes into the working fluid ? And over that time how many cycles has you engine completed ?

Thank you, but that wasn't what I asked you. I asked you how you measure this supposed energy input to the working fluid. Not guesswork thank you.

Thank you, but how do you know ? You can't just pick an arbitrary figure out of the air and say I will put in 500kJ of energy. You are constrained by the characteristics of the system. You can measure and adjust temperature, pressure, and perhaps volume. You then need to calculate the energy (and entropy) interchanges from the 'observerables'. Talking of energy you said I posted the PV diagrams. Yes But I also posted the TS diagrams which are of great use to engineers and I use to answer the question "What is Entropy ?" The area of a PV diagram gives you energy and entropy was introduced originally to answer the question "We need a variable to go with temperature (an observable) in the same manner to also help us calculate energy. Plots of such varaible pairs are called 'indicator diagrams'.

Now that you are talking to me again, please remind me how you arrive at this figure of 500kJ supplied and what is it supplied to ? You do realise that the figure should only include energy added to the working fluid, nothing else ? Is this 500kJ over one cycle or what ?

We need more information. A sketch would be useful. You say a water tunnel. Is it running full ? If so what happens at the divergent section ?

Well I don't agree with either of you. In my view the opening post itself was clear enough, although I will accept any clarification by exchemist as to what he actually meant. I understood it to mean that: An article was published that declared in exactly these words "all knowledge is..." In my dictionary all knowledge includes scientific knowledge, including established facts such as Pythagoras' theorem. The article further states that political correctness is being applied to a particular course in a scientific subject, to whit Chemistry. exchemist appears to me to be asking if this is sensible (science) and providing his opinion that this situation is 'bonkers' I agree with him. In extending these simple observations to the countries and places where they speak different languages I respectfully suggest that both CharonY and Arete are the ones who have 'missed the point'. In particular the question of those who do not speak English is a red herring. Said person must speak his or her own language and the exam in his or her country will not be in English but in his or her own language. So why should they not pass the exam ? No, I would not expect them to come to an English speaking country and take the exam in English and pass. Would you ? Did you read the words 'perhaps we should' at the beginning of my sentence indicating Swiftesque irony ?

Fly though a cloud ? No, the body was made of balsa wood. The twin engines were made of metal and I presume the fuel tanks and lines.

Forgive me but I thought Mendeleev's original wrtings were in a mixture of Cyrillic for the text and Latin for the symbols as most of then known elements had Latin names.

Please give me strength. Go back to the two correct things you said which were 1) The air density inside the balloon is lower than the air density outside. 2) The air pressure inside the balloon is greater than the air pressure outside. ( But - my comment - this cannot be true at the opening or the higher pressure air would simply exit the balloon. This is why the given analysis sets the pressure at the bottom to be equal inside and outside ). Now consider a Montgolfier design; a ball shape with say the bottom 40% cut away to form the hot air entry part. The remaining of the lower hemisphere wiil be curved in such a way as for the higher pressure at the bottom to push down harder on it than the lower pressure pushes upwards further up. At the equator of course the net force is horizontal inside the balloon.

So you are claiming that a pure tension structure made of flexible fabric can support compression ?

I fail to see the relevancy of this to either of my comments. In particular would I be considered racist if I reported a black precipitate on passing hydrogen sulphide through copper sulphate solution ?

The Montgolfier shape is not the only possibility. Cylindrical hot air balloons work perfectly well too. What, by the way, is the point of pushing up on fabric at the bottom ? It will simply buckle or rumple under even the slightest push. It is vital to maintain tension in the skin of any balloon, open or closed. There is even a discussion of this in the article I posted. What a pity you don't like it because it is a nice piece of uncomplicated mechanics that is not often taught these days.

Make that check out to studiot in sterling please. Did you not read the associated text. Only the Carnot includes adiabats

All the basics necessary to compare the stirling (Ghideon please note correct spellung - sterling refers to money, gold and silver) cycle with the carnot cycle are in this excellent extract. It also provides conventional labelling to aid common discussion.

The most successful warplane of all time was made from wood. I know that's dead, but still it's worth mentioning.

I must say I fail to see what is subjective about the result of adding silver nitrate solution to sodium chloride solution. Perhaps we should ban such experiments since the majority of salts are white so white precipitates (if any at all) will be in the majority.