studiot

Capiert, to save further argument over terminology I suggest you research Momentum Transport This is the technical term I think you are trying to portray. There is a whole branch of engineering science about this https://en.wikipedia.org/wiki/Transport_phenomena

Funny I thought I said in my post

The big difference between light and all other waves is that all other waves require a real external medium to propagate in. Light waves carry their own medium with them or alternatively create the 'medium' as they go along. This means that for other waves there is a real something to push against that is not the wave itself. In the case of sound this something is the air. So another agent that can push against the air can push the air molecules in exactly the right way to counter the wave. For light there is no 'third party' involved in the interference and, as Strange notes, it is very very difficult to create another light wave of exactly the right frequency and phase to counter a given one. Until the advent of lasers this could only be done by using the original light ray itself By splitting it into two parts and changing the phase of one part and then recombining the two parts destructive interference can be caused. This is used in engineering to measure small thicknesses of transparent things like glass and oil or chemical films / coatings etc.

You need to study Eutectic mixtures. https://en.wikipedia.org/wiki/Eutectic_system

Have you loaded the Radeon drivers? Look in the bios and see if you can transfer control to the onboard graphics, if there is one and use that. The output may have a cap over it as Dell have also fitted a higher graphics card. It may also be that when you removed the old card control transferred automatically to the onboard graphics. Edit oops I missed one of phi's darn commas.

Felicitations Monsieur!

I will start from the beginning, because the answer is not simple. Something feels hot to touch because heat is transferred from it to the hand. Heat only flows from a higher temperature to a lower temperature. The greater the temperature difference, the greater the rate of heat transfer. Your sense of touch is mostly sensitive the the rate of heat transfer, not the absolute temperature difference. If you touch a plastic spoon and a metal one at the same higher temperature than your hand the metal one will feel warmer, because the rate of transfer is greater. The reason for this is because the heat in the spoons has two separate sections to its journey into your hand. Firstly some heat has to be transferred from the point of contact to your hand. This increases the hand temperature at the contact and depresses the spoon temperature there. Then heat has to be internally transferred within the spoon from the now hotter parts to the point of contact before more can be transferred to your hand. This happens quickly in a metal (or other conductor) spoon but slowly in a plastic (other insulator) one. The speed of replenishment is controlled by the thermal conductivity of the spoon material. Your garden spade is more complicated because the heat capacity (specific heat) of the wood is about 5 times that of iron (about 2.5 to 0.5 in metric units) so the iron blade will heat up to a higher temperature than the wood for a given solar input. So the wood starts off at a lower temperature than the iron and transfers heat more slowly. Both effects combine to make the wood appear (and be) cooler. Since you asked for the property which is smaller for iron I assume you are looking for the heat capacity. The conductivity of iron is much larger than that of wood.

I'd like a closer view, but try garnet if they are indeed crystalline. https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=garnet&gbv=2&oq=garnet&gs_l=heirloom-hp.3..0l10.1083.4067.0.4937.8.7.1.0.0.0.137.671.6j1.7.0....0...1ac.1.34.heirloom-hp..0.8.693.JKU-Tp15PTw https://en.wikipedia.org/wiki/Garnet Can you give us some more details about their location? You can pick this sort of mineral out of the side of the river South Esk gorge in Angus, Scotland.

Since this is the day for jokes. http://www.bbc.co.uk/news/business-36638929

Thanks, Mordred. The point is also that the book was in pure maths but contains some excellent wisdom and is a very good read, not just the extract I posted. It could be called the study of group theory via Scottish Dancing.

Thank you whoever read my last post for the support. For your information, in 1963 I saw a stage performance of Hamlet. The stage effects included a very realistic ghost behind a gossamer screen by edge projection lighting. Yesterday I saw the technique again at the permanent RSS Discovery exhibition in Dundee. Of course edge illumination has been used to illuminate characters in displays since the early days of radio.

I'm sure you know that I was not referring to improving changing or replacing a model in the light of new and better data. That is 'encapsulated' in the example I gave.

I see no one was interested in my Oxford model of a model, but don't you think this is a bit limiting? Another valid question might be paraphrased as If the model appears thus today was it the same yesterday and will it be the same tomorrow? Astrophysics is currently wrestling with this exact question.

Concerning models, this extract from Discovering Modern Algebra by K L Gardner - Oxford University Press may serve the whet the appetite of some to read more. It really is a delightfully clear and easy to follow book.

Your response to this (and my questions) was not encouraging to downright rude. So good luck with your design for whatever it is you actually want.

Unfortunately your English is so poor that I do not understand the question. In particular do you desire a holographic image projected in empty air or do you desire a projection method to place an image onto a physical transparent screen? Is the image to be a static picture or a moving image? Both are possible and examples may be viewed at the Museum of the Moving Image, Futuroscope near Poitiers in France. The holographic solution has already been discussed, projection onto a transparent screen can be performed via edge projection. Many old fashioned display devices worked in this fashion.

There are two different situations for which a different (scientific) method is appropriate. Within these two situations many different methods may eixist. So even at the top level of classification there is no one single 'scientific method'. More specifically; In the situation were we are discussing applied science, particularly engineering, we have the idea of the independent check. When designing or assessing a bridge, an aircraft, a dam or whatever current practice demands that the desing is checked by an independent method and person(s). So a bridge deck may be designed by one person or team using finite element methods, and checked by another team using energy methods, plastic hinge theory or Klein-Logel charts. At a lower level operations should be carried out in a 'self checking' manner which incorporates and independent check. A good example of this is the surveying practice known as the rise and fall method which submits surveying calculations to verification by an alternative arithmetical process. Measure twice, cut once. That was the first situation, the known. The second one is where fundamental research is undertaken. Here an independent check is sometimes possible ( as in the geological dating examples in another's post) , but often only one system of measurements are possible or available. Sometimes the actual measurement is a chance observation. In this case efforts may (should) be made not only to repeat the expereiment but also to take further observations in a range of conditions to place the initial measurement in context and give confidence and credence to it. There is another thread just posted in scientific news here, concerning carbon fixing into the rocks, where this process is just beginning. The whole point of this is that mere repetition is (as you rightly said) dangerous. Verification should be by different (=independent) means. And if there are independent means if follows that there is more than one way.

Firstly an apology. I see I mis-spelled your persona name in post 18. Sorry it should have been BJJ. I meant none of these. The independent check is embedded in scientific and technical processes but there is considerably more to it because it is not always possible. The whole point is the word independent. Do you understand the significance of this?

I seem to be lacking an answer to my straightforward post 18 ?

Let's be clear about technical matters. JBJ, you started this thread with two wrongs and a right. A right because I and the technical world, and indeed most of the non technical, agree with you that it is dangerous to rely solely on one assessment. Wrong on two counts because in your ignorance you accuse the technical world of following a single assessment creed. I will allow that you do not actual understand technical matters but before I enlighten you, perhaps you would be so good as to answer this question. Suppose you were in a hospital, suffering a life threatening condition, and about to receive a life saving treatment. Would you think it right and proper that the dosage to be administered received an independent check before you received it?

It is good that you are trying to tell us what you want to do. But eddy currents at DC? Can you provide a diagram for discussion?

John, thank you for correcting my spelling, I will offer you the same courtesy one day. You called for an experiment. I quoted a series. But you ignored it. I stated there was a dominant factor. You offered effects that can only make small differences to the cooling times, because they are not dominant. The rate of cooling for the hotter liquid will be greater, Do you deny this? I also quoted a method of increasing the rate of cooling of either liquid, which has nothing to do with the fringe effects you mentioned.

This is called Coulomb's solution and is for a perfectly homogenous ground. The hemisphere is because it assumes the charge source is at the surface. That is the test electrode is small compared to the distance through the ground. So the ground is only half a sphere. The space above the ground is the other half. The the electric potential is hemispherically distributed. Resistivity surveying depends on finding divergences from this solution to indicate changes within the ground. Note that usually two electrodes are not sufficient for the currents and voltages involved and that at least four terminal Wenner arrays are used. http://gpg.geosci.xyz/en/latest/content/DC_resistivity/DC_principles.html https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=wenner+array&gbv=2&oq=wenner+array&gs_l=heirloom-hp.3..0l5.875.6016.0.6500.14.9.1.4.5.0.141.1016.2j7.9.0....0...1ac.1.34.heirloom-hp..1.13.1126.YtWo4Iq2TcY

John,why you are making this uneccessarily difficult? My experiments over several years conducted (pun intended) for oither reasons confirm that Newton's law is the dominant factor in this situatiion. Further I confirm that if you wrap a cloth soaked in cold water round the vessel it will dramatically increase the rate of cooling. Please note also that this is a standard high school physics experiment.

The milk will cool the mixture by a fixed number of degrees, whatever temperature you add it in at. The longer you delay adding the milk the more quickly the hot water will cool. (This is known as Newton's Law of Cooling). In any case you need to leave the bag in unmilked water for a period to infuse as properly as it possibly can in a cup.