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justfloating

Listed below are comments made by justfloating between Thursday, 8th January 2009 and Sunday, 11th January 2009.

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Light bulbs! 7:48pm on 11 Jan 2009 (128) - petepassword

Now that is it. You think 11W CFL at bedside position is OK. So since the largest CFL in normal sale is 23W this is approximately twice as powerful.

The light flux from a bulb uses the squared law. So a 23W bulb needs to be further away by 1.5 times the distance to be the same light intensity.

Assuming you can reach your bed side light. It is 1 arm length from your eyes.

Therefore the rest of us with a central light suspended from the middle of the ceiling can only be 1.5 arms length from the middle of the room to see as clearly as you.

It is a tad cramped if we try that!

Put it another way, if I am expected to read in our room at present at 3 arms lengths from the light of 23W CFL. You should have a 3W CFL in your bed side light.

Why are yours so wasteful?

The room worked well with a 150W filament bulb and we all shared. Now we all need reading lamps?

One final point is: who would invent a light that had more than half of its output directed at itself. Think about it. All the tube surface have to be covered in phosphor to convert the UV radiation from the mercury discharge. But it is in a loop that points at itself. There are no reflectors. Bright designers!

One final, final point is I found a graph of the light output vs. temperature for mercury discharge fluorescent tubes (CFLs). At freezing the light output is 40% of the light at normal working temperature. It is a gradual decline not a step. Maybe that is why cellars and unheated stairways seem to have light problems. Something that a normal filament would not care about.
The Glass Box. 7:55pm on 10 Jan 2009 (37) - DMcN - Oil on troubled water, the head on a warm beer, ice on a stormy Ocean, clouds in the windy sky. Other things do, but it depends on how they are buoyed up by excess gas. Is this your issue?
The Glass Box. 11:54am on 10 Jan 2009 Re (3) I did listen again. It still was not sensible after the third time. Is the implication Australia and NZ has only just adopted the use of courts or that Scotland does not have the money to ever replace/refit its law courts.

DPP guy wanted more openness. Yippy. I was quite happy to take holiday to watch the court case against the lady that tried to kill me. However it was the CPS that hid the case, and never told me that it would not proceed, until I finally got it out of the police months later. Then the lady did have good political connections.

Maybe the DPP guy should consider his own realm first.
The Glass Box. 8:54pm on 09 Jan 2009 Beware very serious cynicism.

I was relaying what was on PM tonight and mentioned last night had an Autism genetic screening slot, and tonight the high levels of measles was reported.

So on the off chance I googled: "Simon Baron-Cohen MMR"

So making out that in 5 years they, might, could, maybe, filter out Autistic children before birth means that, by implication, Autism has nothing to do with environment after that point.

Even if it was not an intentional misleading idea, Simon Baron-Cohen should have seen the implications of these claims of a potential break through.

It was him that "condemns leak of unpublished autism study and alarmist suggestion of MMR link".

Is he so removed from reality he did not see the connection.
The Glass Box. 6:00pm on 09 Jan 2009 Don't ttttease Paddy.
The Glass Box. 5:38pm on 09 Jan 2009 NO to cameras in court.

I was a bit confused how Scotland was so different from New Zealand. Is NZ the only country rich enough to build new courts? I think I will listen again?

Personally I would like to be condemned by a jury not a media frenzy.

However, for all others involved in a trial (the innocent) their performances will be available for ever. This will help further the unwillingness of witnesses to come forward.

Doing your good turn at one instance of time should not leave you identifiable for the rest of your life. That is a sentence of fear.

This would be good for the court system, they can fight all day about experts and trace evidence and baffle any normal jury, without the risk of real witnesses that might clear away their fun.
Light bulbs! 1:51pm on 09 Jan 2009 (110) - mittfh - You are right most of these little boxes convert mains to DC as their first stage. So DC looks good. However DC is so much more dangerous.

During a DC shock your muscles contract differently. Even working on a 24V DC system in a damp atmosphere I found it hard to control my hand spasms holding the spanner. I once worked live on a 120v DC system, I had to threaten resignation before they improved the safety. You end up with serious hand burns in accidents.

The other issue is losses. At 24V you have currents of 10x in the wires wrt. to 240V. The wire losses are the square of the current. So the resistance of the wires has to be radically reduced, and so end up bars of metal.

There are changes in the voltages used in cars. There is a trend to move up to 42v type systems to reduce the copper content.

It is also why the Grid runs some lines at 400,000V.

The idea of the contactless plug has been around for years. One company failed and was bought out last year. Someone tries it regularly. The issue is efficiency. You just can not get power to wonder unguided through air or insulation. You can do it, but over very short distances with respect to the size of the unit.

In general 50Hz buzzing transformers have past their day. All the little black power bricks are running at high frequencies so that they can improve the efficiency through small high frequency transformers. High frequency meaning anything up to the range of 400kHz.

People like CamSemi have based their future on providing high performance converters. It is companies like that who are so important to our country and world friendly products.

So if high frequency is good why not make the mains higher frequency. But then you can not send it anywhere. The wire just end up like a huge antenna.

So why not make mains DC? That is the idea behind the cross channel power link and the proposals for the supergrid in the North Sea. The down side is the converter to get back to useable voltages at the ends. Imagine the size of a little black brick powering your computer: 70W. Drax is 4GW. So that is 57 million times to small!
Light bulbs! 00:07am on 09 Jan 2009 I can see efficiency loss for those who use electric lights on bright sunny days.

However, I open the curtains instead!

Heat and light are highly correlated with the sun behaviour in the UK. Amazing how life evolves.
Light bulbs! 11:51pm on 08 Jan 2009 (89) - NormatheVole - Your basic assessment is correct but incomplete.

The major assumption is that the gas appeared at your house spontaneously.

Actually, any extra gas requirement in this country is supplied by LNG.

So the first issue is it must be liquefied. This cost significant amounts of energy.

Then the LNG has to be transported. During its travels it must me maintained in the liquid state that requires venting. The special ships use the vented gas to supplement the engine fuel. The issue of a stranded vessel never seems to be covered.

Then the madness in the whole system: It costs energy to turn back into gas so it can go down the pipeline.

There is a small issue of pumping it as well. As with all distribution there is a cost and wastage through leaks. Yes there are significant leaks.

You then burn it in a boiler that it switching on and off as it is hopefully at its house temperature. Boilers cycling, on and off, are far from 90% efficient. A boiler sized for bulk heating a house should not be used to maintain a temperature.

So light bulbs and TVs and other electrical appliances actually save the cycling of these oversized boilers.

This is also the missing argument in the COAL IS EVIL issue. When any calculations are done they always compare the heating factors that are about 117 vs. 212. So coal is twice as bad. What they miss is the coal comes out of a pit and the power station would be built at the end of the conveyor. However, gas comes from a long way away and further imports will be liquefied. The gas is assumed to be pure. It comes out of the ground and during liquefaction the 1-10% CO2 is vented to the atmosphere. However this is trivial to the 30% (by CO2 equivalence) of the gas that is used to get it to the UK via liquefaction. (We will ignore the 6% venting and other losses but then that is only methane!) So a new gas installation starts off at far worse than 70% efficiency. But those figures do not include the ship maintenance etc. But then it does not include the mine maintenance. So COAL is not that bad. There are also integration savings that can be made from a combined pit/power station that would mitigate any methane gas escape from the mining.
Light bulbs! 9:19pm on 08 Jan 2009 If they were "brilliant" why would we need forcing?

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