studiot

I found this articel wallowing in woollyness. Unfortunately I see this as all part of the trend towards mysticism and woo replacing hard science and facts. As far as ZPE is concerned there are even books, websites and societies promoting magic wans to control the ZPE.

Let's try again. I asked for a few numbers. I understand you have a 120v transformer capable of supplying the 30 amps and rectifiers to suit. So what is the output of the transformer ? You say you want a variable voltage DC supply. Between what voltages ? You do realise that your design is unable to go right down to zero volts ? I understand you have a reservoir capacitor, or bank of them. What are their characteristics ? Have you thought about protecting both the load and the psu from overload - 30 amps is a lot of current ? What are you actually driving (supplying) - the requirements of the load make a real different to suitable circuitry ? (Good) engineering is requires drawing a balance between competing requirements and resources.

No of course it doesn't. But the very fact that you have bothered to state this shows that you have not understood the method of deduction. Again of course, but so what ? You are not considering the appropriate information. Today we know that the Earth is moving at an average speed of 2.575 million km/earthday In Roemer's day they knew the average period of Io's orbit of Jupiter to be around about 1.8 earthdays from Cassini's observations, taken over a complete earthyear. In that time, the Earth will have travelled about 4.5 million km. They did not know this because they did not know Earth's speed accurately enough. But Roemer realised that there was a big difference depending upon which direction that 4.5 million km were measured. Along the line of the Earth's path or perpendicular to it. This in turn makes a difference, not to the Io's period of obit, but to when Io appears and disappears. Perpendicular earth travel makes no difference to when Io appears or disappears. But when Earth is travelling ( as near as possible ) directly towards Jupiter that period appears to be shortened by 15 seconds and When the Earth is travelling directly away from Jupites (six months later) the period appears lengthened by 15 seconds So there is a variation in the apparent period of 30 (+/-15) seconds over a full year. Now it is very important to understand what this information will tell you and what it won't. The time variation from one Io cycle to the next will be nothing like this number because the Earth is still travelling towards or away from Jupiter. It is the comparison with the average that matters and where it shows up. So Roemer did not have a good radius for the Earth's orbit and records that have survived do not show an actual lightspeed calculation. He estimated that when the Earth was travelling directly towards or away from Jupiter the light had a corresponding shorter or longer distance to travel roughly equal to the radius of the Earth's obit, because of the geometry of the situation. So the peak to peak variation corresponds to the diameter of the Earth's orbit and the deviation to the radius. Does this help ? Actually I realise that I didn't put that very well. I should have said along the direct line between Earth and Jupiter or perpendicular to it. In other words when earthspeed is perpendicular to that line it make no difference to the transit time for light as the distance between the two does not vary over a couple of days. But when earthspeed is along the direct EJ line the distance Earth travels will be additive or subtractive from the EJ distance, that light has to travel, therby changing its travel time (slightly).

Yes I fully agree that a vacuum seal is developed. But the seal is separate from the clamping force, as shown in this video from Kilner. Kilner jars are the Uk equivalent of your Mason type. They are for home preserving, not commercial practice. The difference being that the commercial jars and lids are not designed for reuse and their 'screw' down force is minimal, unlike the home variety. This video is very clear.

Some switched mode supplies have no transformer, the better ones do, the sort of swmpsu you and I are used to, are relatively low power and may be implemented simply as a capacitor store type. Many of the cheaper ones do not in fact meet the UK wiring regulations. But the OP type is a 12 volt 30 amp+ supply. these are available commercially ( I have one) that are used by radio amateurs, marine folks, anyone who wants a mains supply to replace a 6/12/24 volt Lechlanche battery. Higher amperage ones are used as vehicle starters and fast chargers. in garage workshops. One way to achieve this is to put controlled rectifiers in the bridge, but at these current levels any design is always fighting the short time when positive current can flow into the reservoir, compared to the period of the ripple voltage, necessitating large value capacitances with robust rating to take the inrush current that may need to be several times the average current (so 30 amp might become 90 - 150 amps pulses ) . The ripple on commercial units is often acceptable because they are only powering lighting or machinery, both of which have inertia of their own.

Would any of those who favour the low pressure theory care to offer a mechanics explanation as to how a pressure differential developes the necessary restraining torque on the cap ? Here also is another picture this time of a marmalade jar. The new jar shows the cap in its unopened state, looking like thousands of other such lids with one-piece lids. And the particular supplier used to use that type of cap with several clutch tabs forced onto the ridges in the glass. But the supplier has recently changed to a two piece lid for reasons I don't understand, A dismantled new lid (sorry I had to distort it to get it apart) is also shown in the photograph. I can't see the gain to the manufactured that more than offsets the extra manufacturing steps necessary to fit the lids in this way. I am also not sure if the lids are mechanically crimped onto the jars or are fitted hot and allowed to shrink on cooling. Either way I think the restraining friction is a result of this clamping force.

I'm sorry you have chosen not to answer my questions. For those with a genuine interest in what Roemer did, or did not do, there is a good readable account not only of his part but the events leading up to his work and the necessary conditions for him to be able to cary it out in this book. It should be noted that the fact light has a finite speed was known to his employers Cassini and Picard at the Paris observatory.

This thread seems to have got bogged down in a dispute over Roemer's actual reading. Thus only the first of thye fout claims have been discussed. I am interested in the other three, particularly the last two. Please expand on both of these.

Well +1 for the whole post I never knew any of that. Thanks.

Yes it can be very crude. But it also suggests a deeper philosophical point. The practical fact thst you can have two (or more) timers delayed by a controllable amount so that they can be combined with another suggests a background time always ticking away regardless. I'm not calling this absolute time since it has no defined or unique origin.

One drawer in every good kitchen should include several good pairs of scissors, a pair of tongs, a couple of screwdrivers, a couple of pairs of pliers and one or two skewers.

Even a pinhole is a gaping chasm for air / microbe mix under pressure. And I don't usually have handy hardened pins for puncturing. The glass and contents do not heat up as quickly as the metal for two reasons. Firstly they both have a much lower heat transfer coefficient than metal soit take longer for the heat to penetrate. Secondly it take more heat to heat up as they both have a higher heat capacity. Any air in the top of the jar will also heat up quite quickly from the metal and so the pressure diferential will be lower. 😄 I never thought of that, when I was younger and stronger. Silly me. +1 But seriously with all these politically rather than scientifically ways of saving the planet - or cynically saving the manufacturers a few coppers - many liquid/semi liwuid products like youghurt used to come in plastic pots, womplete with a replaceable plastic lid over the seal. Nowadays they have dropped the plastic lid ( a very minot % of the total plastic in the packaging. to great inconvenience of customers. We are fast running out of old lids that have been rewashed many times (you can only rewash so many times)

Some manufacturers really seal their jar tops on tightly. So most of my family can't open them. Up to recently I have managed to supply the neccessary brute force, but I am getting older. Once technique I can really recommend is to use a hair drier, on max, bot perhaps 30 second to 1 minute. Play this directly onto the metal top only. the metal wi;; heat up quickly and expand, but the glass will not so voila. The result is a dead easy to open jar.

I'm pleased some find this thread interesting to discuss. A nice change from AI or non-relativity. No I didn't envisage probability being involved, but that is not to say it isn't. If you see a connection please offer it up for discussion. My input is not meant to be prescriptive in any way. Having said that and thinking further about feed forward, we have the possibility of another mechanism. Time delay. It is possible for the error correcting signal to reach the output at the same time at the main process by delaying one or the other appropriately. The effect fro instance on transmission line loudspeakers is dramatic whrn you get that just right. Similarly I remember palying with springline (and later digital) reverb units to explore the audio effects available.

Thinking further about this subject a number of questions occur to me. 1) Does running several kw 24/7 present a fire risk ? 2) Does this constitute commercial use of the land for planning or local tax purposes ? 3) Does this in any way affect the buildings insurance ? 3) If this is now part commercial use, how is capital gains tax affected ? 4) Again if this is now part commercial use does the property have any restrictive covenants against this ? I say this because UK law is heavily restrictive against the ordinary citizen in many respects. For instance if you have a stream/river in your garden as the 'riparian owner' your are generally liable to maintain the banks. But you require a licence to place an electricity generator in the water stream, which is genereally not granted. By contrast in Europe if you want to do this you can actually get a grant towards the cost.

Can you honestly not see that ? 1) There is no capacitor in the curcuit between the ac drive and the transformer primary 2) There is no additional inductance in the form of a motor winding in the secondary circuit of the transformer 3) Neiether the primary nor the secondary circuits are grounded. But you said This circuit shows all 3 changes.

Thank you for wasting my time. I just looked in but I think I will go back to watch the ending of the late night film, whilst you have a nice discussion with the moderator about your attitude.

Well a few numbers might be useful on you psu, don't you think ? As it is not clear whether you are talking about an emitter follower type pass transistor or a collector follower here are a couple of pages to cover either or both eventuality. It would have been much more helpful if you had stated you expected current draw and voltage adjustment range. Since you are using power transistors I assume substantial current draw and therefore you will require all the base drive current to pass through that one (variable) resistor. There are several methods of overcoming this. One is to use a darlington configuration for higher power transistor gain. The other is to add fixed end resistors in seroies with the variable one to ensure that one end of the track is not burnt out. An emitter follower type (circuit 1 in my attachment) is not short circuit proof in respect of the load so again, especially if high powers are envisaged, some protection is best. The collector follower type (circuit 2 in my attachment) is inherently short circuit proof. You should add a high value bleed resistor across your filter/reservoir capacitor. This will discharge a subtantial energy source safely when the supply is switched off. It is unknown what your resources are or if you are using up old stock (if so well done) so further discussion of this would be fine if you have any more questions.

Three members already working hard for you, though you logged straight off after posting and haven't been back since. If this is a serious question, please give some context.

Circuit diagram ?

Well I understood it as one of your better answers.

Doesn't work for me either. It's more basic than that, I can get the drawer open and then close it again but the w10 system insists there is no disk and won't open the drive again. Thanks to SJ for reminding me of that. I remember now finding taking your drive away to be another of the famous 'updates' M$ forces on you even for w10, so going back won't likely cure it either.

It's a long time since I did any work on chip cooling efficiency, but then the raspberyy pi is getting long in the tooth itself. Yes chips will work at 100o +, however the hotter they are the shorter their service life, especially at the high end (It's a non linear degradation curve) I remember that the most efficinet chip cooler were not air cooled but of the 'heatpipe' variety. A suitably volatile liquid is sealed in a tube or pipe directly connected to the chip as metal to case. This carries the heat rapidly away to a secondary heatsink thay will be (possibly force) air cooled, by evaporation and condensation. The cooled liquid then runs back inside the tube to carry on the cycle.

There seem to be a lot of things they haven't told us. Like heat pump suppliers don't tell you you need bigger radiators because they run at lower water temperatures. They may also have super insulated the premises in the article.

Not sure I follow. A UK domestic gas or electricity bill will never be zero due to the standing charge (which is unconscionably high IMHO). Added to which, £40 per month is good for a summer month for someone who doesn't have gas since that powers cooker, fridge, freezer, washing machine, drier, domestic hot water and uncle tom cobbly.