studiot

The word 'Abstract' means 'apart' in the sense of 'removed from' not 'different from' . Man has been abstracting qualities from things around him for thousands of years (as well as metals form ore and alcohol from fermentation products). So the ancinet Greeks abstracted the ideas of a square, circle triangle and so on from the natural shapes they found.

That rather depends upon what Tim meant v what Leon meant. The potential confusion I refer to is that of light energy v total energy. The light definitely looses energy in interactions with an attenuating medium. Clearly that lost energy is gained by something else. Talking of that loss/gain, Can it be said that this light that is lost comes to an abrupt stop and therefore decelerates?

Plenty of help available here for those that are interested. A bit more about this subject that might be useful. We say that a number (say a) multiplied by itself n times is "a raised to the power n" we write it thus an. This site is unusual in that the tools along the top of the entry box allow superscript X2 (and also subscript) X2. Both of these are much used in technical writing. n is also called the exponent, as Strange says. But beware he has supplied the computing definition of "mantissa", which is different from the mathematical one. So I would avoid that term until you know more. Anyway powers of 10 are special because they move the decimal point of a number thus: 2348.56 = 234.856 x100 = 23.4856 x 101 = 2.34856 x 102 = 0.234856 x103 = 2348.56 x10-1 = 23485.6 x 10-2 = 234856 x 10-3. So with this notation we can get rid of the decimal point altogether. But this is at the expense of having to write a superscript. Note also that I have used x 100. Anything to the power 0 is equal to1 So some calculators and computers may use an alternative method which can be written all along one line. This is called the E or e notation (after exponent, remember them?) So my example above may appear on a calculator like this 234.856 = 234.856 = 23.4856E1 = 2.34856E2 = 0.234856E3 = 2348.56E-1 = 23485.6E-2 = 234856E-3. Here is a little webapp to play with. https://www.calculatorsoup.com/calculators/math/scientific-notation-converter.php The point of all this is to use a format that helps avoid arithmetical errors. Suppose you have a problem to work out that leads to the expression [math]\frac{{0.0035\;x\;56892}}{{120\;x\;100}}[/math] We can rewrite this expression using powers of 10 [math]\frac{{3.5\;x\;{{10}^{ - 3}}\;x\;5.6892\;x\;{{10}^4}}}{{1.2\;x\;{{10}^2}\;x\;1\;x\;{{10}^2}}}[/math] Some of the powers of 10 can be cancelled out. This is a very good reason for writing the fraction as I have done, not using the division sign. [math]\frac{{3.5\;x\;5.6892}}{{1.2}}\;x\;{10^{ - 3}}[/math] Now all the numbers to multiply or divide are in the range 0 - 10. Wew should first divide the 3.5 by the 1.2 to keep it that way. Then multiply the result by the 5.6892. This maintains the best possible accuracy. Note also that I have collected together all the remaining power of 10 (-3 in this case) and moved them out of the fraction. [math]16.5935\;x\;{10^{ - 3}}[/math] Again going to a number between 0 and 10 and a power of 10 we have [math]1.65935\;x\;{10^{ - 2}}[/math] Hope this helps

It is said (the WHO) that 'food waste' accounts for 10% of our greenhouse gas emissions. https://www.bbc.co.uk/news/science-environment-51450727 So how much do you think you waste?

I feel this could be a misleading statement. What about attenuation ?

What sort of storage facility is it that allows such chemicals to vapourise and mingle freely? Are there any deposits of white or coloured powders on the cabinets?

Mr Bond, "If I told you the answers I'd have to sedate you permanently"

Are you truly able to go anywhere the work takes you? You must have referred to many papers in your studies. Look to see what those sources/institutions are doing now. Perhaps write to them. One may have an opening for you.

If you know what all those chemicals are do you really expect us to guess on that little information ? Pose a proper question in proper detail.

The classic story of how to defeat an superior alien AI robot. Write P.T.O. on both sides of a piece of paper and hand it to him. You need to break out of the viscous circle your thinking has got you into. I am minded to reinforce Eise's post, but realise that this is Philosophy. Or to observe that Penrose, in his later years, endorses an explanation of quantum mechanics that involves the mind in the quantum process and negates the idea of past, presebnt and future as separate disjoint entities. Space has Euclidian geometry. Spacetime does not.

Yes I understand what you are saying. But I wish to challenge that since in my view the purpose of the scientific (have we changed from statistical ?) analysis is to establish a measurable confidence interval within which any result can be accepted and outside which any result can be rejected. The two purposes are inextricably linked. Your bat example demonstrates that exactly, in basing the decision to choose bat A on test results, however scanty. I think this was just over broad brush treatment and guido was correct in distinguishing sources of cholesterol. Coincidentally I am following a course in Phsychology at the moment and the last session was all about eating disorders and obesity. That medical studies indicate that little or no correlation between overweight conditions and cholesterol levels was brought up and discussed.

This would be a good place to start your research. Read Chapter 10 in particular. http://www.siirt.edu.tr/dosya/personel/mesrubat-ve-mesrubat-teknolojisi-ders-kitabi-siirt-2018221143430322.pdf

I am asking if that is consistent with their null hypothesis or a failure to establish a proper null hypothesis?

You don't actually need velocities (numbers) to answer this. I was however thinking of taking A or B as at rest and the other as uniformly moving away indefinitely, which is easier than flyby and requires no external observers, just the 'stay-at-home' twin and the travelling twin.

Is 78 out of 100 statistically different from 80 out of 100 at the stated level?

Well I certainly am confused. Perhaps you would be so kind as to explain it to me.

Yes they would. It is instructive to conside a slightly simpler situation (I think you two have been chewing over this) where there is no acceleration, both 'twins' are in constant relative motion at all times. Clearly they can only meet once and then separate for ever. But in doing so how does each consider their aging compared to the other one? Since you have used four years in some examples, whose fourth birthday comes first?

That's why the regulations concerning the use of X rays have been constantly strengthened over those 40 years?

So I look forward to a statistical distribution analysis of place names along the 36th parallel, by first letter. Wouldn't it be more fun though if T were the 36th letter of the alphabet?

The 36oN parallel also goes through Tokyo, Tsingtao, Knoxville and more or less bisects the sea between mainland Greece and Crete. So what (is the toponymy) ? You also mention Geomorphology. So where is the connection?

Why should you 'allow' it ? This sort of thing is exactly why n is not equal to infinity, whatever that means. Some writers are more particular and strict about specifying sequences such as 0., 0.99, 0.999, ... ( are you aware to the 3 dots convention?) than others are. n is always finite, but never terminates. ( ie there is no greatest n) And it is this no greatest property that we use here. I suggest you look up the definition of a 'Cauchy sequence' https://www.google.co.uk/search?source=hp&ei=9LE9XrzbOYaOlwTq9onYDA&q=cauchy+sequence&oq=cauchy+sequenc&gs_l=psy-ab.1.0.0l10.758.6748..9392...1.0..0.418.2702.7j3j1j2j2......0....1..gws-wiz.......0i131j0i10.5toJS2iktfs See also this thread here

Before deciding on you model it would be wise to collect some data. 1) The impact energy can be estimated from the mass of a laden aircraft and its approximate airspeed (say 200 mph). this site has useful data. https://en.wikipedia.org/wiki/List_of_airliners_by_maximum_takeoff_weight 2) Another picture from the referred to by StringJunky might be more useful (the one pictured above is one of a series). This other one shows the floor construction. Further information would also be necessary because it does not readily explain the final collapse mechanism in SJ's picture or the structural members in the outer walls. 3) The outer walls were definitely of framed construction (there was a large window area). I am not sure how wooden walls would model this. Ronan Point collapsed due to an internal gas explosion the blew out the supporting panels (note here the outer walls were heavy panels with small windows). That building acted like a pack of cards when one edge card is removed. The modelling was easier because, as you can see from the pictures, much of the block remained standing. So (part of) six stories were taken down and re-erected in the BRS 'catherdral' lab. There tesing was carried out by jacking to determine the sort of pressures required to knock out a wall section. So the model was full scale, but only of part of the structure. That was all that was needed. How much of the full structure would be required to model the twin towers would be a matter of structural engineering, and it would suprise me if that has not already been done.

+1 +1 Folks are trying to help you here but you definitely need to clarify your thinking. Perhaps if you were to base your question(s) on conventional fire analysis that would help. Are you aware of the concept of 'fire load' ? https://www.google.co.uk/search?source=hp&ei=5Cc4XvKACceHjLsP66ShwAs&q=building+fire+load&oq=building+fire+load&gs_l=psy-ab.3..0i22i30l2.2066.5876..6192...0.0..0.1094.7148.0j2j3j3j2j0j4j1......0....1..gws-wiz.......0i131j0j0i3j0i13j0i13i5i30j0i8i13i30.c-32UuhPEzk&ved=0ahUKEwjygsT1xbXnAhXHA2MBHWtSCLgQ4dUDCAc&uact=5

A real life demonstration rather than a computer simulation? If so was it documented? If so can you provide a link to it? Have you not read the information I have already provided ? Did you try Google? https://www.google.com/search?q=Ronan+Point&client=firefox-b&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj3yevambXnAhUTesAKHcB-A8oQ_AUoAXoECBAQAw&biw=1366&bih=646 I have never heard of anders thingy and judging by the reports form other members here, I don't think I particularly want to. But I recommend against getting bogged down in discussions over conspiracy theories. If you genuinely want to study the (structural) mechanics of what happened by way of testing a physical model then you need to be discussing structural mechanics. I have already outlined the SM of the Ronan Point, but I don't know the details of Twin Towers, you should provide these. I said I thought Twin Towers wast post and beam and that seems to be borne out by references to steel framework members. We have had a detailed thread here from someone who was convinced that material failures were a large contributor to the collapses. There were also too many suspicions of conspiracy in that thread and not enough enginnering facts. I think it was this one So the choice is up to you. Do you want to discuss Engineering or Conspiracy ?

That's what I said.