gcol

If it looks like a duck, quacks like a duck, walks like a duck, must be a duck..........not. Drawing inferences and conclusions based on inadequate analogies should be a logical and scientific no-no. Cars and humans? Even worse than comparing the shape and nature of space-time to an expanding party balloon, except for childrens' parties. All in my humble opinion, of course.

Pressure, yes. The skin might burst before the band gave way. The next stage might be to use a plastic bottle, bottom cut off with skin banded over it, then tubing tight fitted to hole in screw cap, draining into receiving container. ( assuming the salt solution will always do the volumatic expansion). After that, it is lab tech experimental ingenuity using whatever equipment comes to hand Apologies. It appears I have not paid due attention to the three types of osmosis. (natural, reverse, and electro). "natural" membranes are probably only suitable for natural osmosis, possibly for electro, but unsuitable for the high pressures required for reverse. Sorry.

The easiest way, for experimental purposes, was to stretch the skin over a jar of either the fresh or salt water, secure with an elastic band, then immerse it in a container of the other liquid. Easy to experiment with different membranes this way.

Are you sure this is correct? The voltage accross any individual cell in a battery cannot normally be greater than the cell's normal potential.( unless perhaps it is being charged). If you break a chain of similar cells in the middle, you will get half the original voltage. In general, the same applies to series resistors and capacitors, no?

I made one many years ago using various animal membranes. The easiest to obtain, and least messy, was fish skin. That is one of the main purposes of fish skin. The skin of freshwater fish is designed to prevent salts leaching out, and the skin of saltwater fish to prevent excess salt entering its body. The tricky bit, once you have been to the fishmonger and skinned your fish, is physically fixing it between your liquids.

Japanese whaling is a very potent analogy. I had already thought of it, but thought it too inflamatory. As for the carrot, can you make sushi from carrots? If we don't keep up the pressure, they will assume they have won. Just keep on slugging away.

I suggest two possibilities: 1. A politician's question, which the sensible politician only asks when he is sure he already knows the answer. In this case he has guessed wrongly. 2. Kite flying, in which case his kite is a dud, or the wind is not blowing. He should build a better kite, wait for a windy day, or find a different hilltop.

Indeed. But when "the media" is controlled by an avowedly staunch right-winger and probably militarist, the debating ground is hardly going to be neutral.

Is it your point of view then that the yellow-bellied throat warbler is dispensible, whereas the red blooded military hawk is sacrosanct? I suppose it is arguable, though amusing.

This thread has prompted discussion in a direction I had not anticipated, and generated unexpected heat. I did not expect the emphasis to be on the technical problems, which is why I put it in politics. I saw it as an example of the law of unintended consequences, or how good intentions can go wrong. But perhaps I erred in not being specific enough in my opening post. The point is that wind farms of the scale necessary to make a significant energy contribution have a huge environmental impact. an impact that, when push comes to shove, is bound to cause considerable resistance Wind farms were originally joyously promoted as part of a low-impact scenario to counter energy and carbon dioxide problems. The practical problems of implementation are only now becoming slowly apparent. I used the military example as a high profile and unexpected one, to avoid the usual circular arguments that would have occured had I used nature conservation, ornithologists and general nimbyism as initial examples

I had the impression that it was not the atmospheric turbulence caused by the rotating blades that was the real problem, but rather scattering effect of the metal blades caused by the varying angle from root to tip to achieve cyclic pitch, rotating. (awkward sentence, hope you know what I mean). Some supporting evidence for this seems anecdotal regarding plastic blades having less effect. Imagine having a very large array of radar reflectors whirling around.

That was supposed to be a big secret.....big whirly things on the superstructure, to disguise the ships as...you guessed it, harmless wind turbines. but moving through the water at 30 knots? Back to the drawing board, matelots.

The UK times newspaper is continuing with the story in a very calm and matter of fact way. NATO, Europe, is becoming very concerned. Quote: "The Ministry of defence is now objecting routinely to all wind farms within line of sight of radar stations, irrespective of distance. There is currently no known technical solution" (my own added emphasis). "Britain discovered the blind spots during tests over a Welsh hill farm in 2004. Pentagon experts were invited to observe subsequent trials."

I have read that they are indeed. Their interference is likened to that of moving waves at sea. A scattering effect rather than a fixed shadow.

I suppose the wind farm industry sees the military getting in the way of their profit, so are a bit upset. But citizens who don't want the ugly great things in their backyards, blighting the neighbourhood and blotting the landscape (nimbies, and those that don't want chopped-up birds polluting their lawns)are cheering the military all the way. Adversity makes strange bedfellows and creates strange alliances.

The story that broke in the UK was that two airforce jets were flying fixed patterns around the 'mills, so that the effect on radar detection could be quantified. All going to plan until some lowly erk (possibly the tea boy)noticed a third aircraft in the vicinity, and inocently asked why it did not show on the radar. Lots and lots of red faces and panic. Then I googled a bit, and was surprised to find such a large military tank trap in the way of alternative energy sources. Protect you from one danger, then dump you in the path of something potentially much worse. Hobson's choice?

Time may well be an illusion (and we all may be just dreaming). But until a new Einstein comes along, it will have to do. I mean no time, nothing happening?, How inconveniently tedious and plain boring. Not to mention the expense of tearing up all those standard physics textbooks. To paraphrase a well known philosopher, "If time did not exist, it would be necessary to invent it"....Oh, wait, someone's already done it..

The American military is blocking windpower schemes on a "presumption of hazard" basis. The big 'mills interfere with radar. Apparently any windfarm within a 60 mile radius of a radar installation is a defence hazard This appears to be a slow-burner of a story that has recently had a light shone on it (for me) in an article in this mornings U.K. news. I offer no links. Just search "radar windpower", and choose your own prejudice. So, want to save the polar bears and penguins? Don't join the armed forces, their priorities differ from yours....

It is called a PERISTALTIC pump. Google images gives many variations.

The type just mentioned is called a peristaltic pump. Some pump manufacturers make both peristaltic and diaphragm types.

Diaphragm pump. No moving piston. I have one, but it works at relatively low pressure. Perhaps that is its design limitation.

Martin:: Help! I don't see a problem with the balloon analogy, except in the limitations of the mechanics of a party balloon. My balloon has no skin, requires no space for expansion. It makes its own space. It is driven by its own internal forces. It is complete within itself, containing all we know or can know. Our own cosmic balloon is all there is. It may or may not achieve equilibrium. It may or may not contract to a singularity. Imperfect analogies lead to flawed reasoning

The obstacles placed in the path of innovators seem insurmountable. In the building industry, they include: Planning control regulations. (new builds must generally conform to existing street scene). Building control regulations. The bottom line of commercial profit. The stranglehold of standard-trained architects and their standard protective trade bodies. The reluctance of the building trades to depart from their areas of comfortable "expertise". As for straw bale, once having taken prevailing climatic conditions into account, Almost any material could be pressed into service between suitable top-hat and boots (roof and foundations).

....... Or perhaps nowadays all hidden in a zip file.....

Should there be a "trousers" button for all member searches?