Here is a list of all the postings Martin Kyte has made in our forums. Click on a thread name to jump to the thread.
|Thread: What sort of things DO NOT inspire you|
|Thread: Coal being phased out|
I'll have a go at a partial answer at least with the caviat that this is my understanding only and I am not a climate scientist. Broadly speaking :-
Prior to large scale 'biology' on the planet global temperatures were determined by solar irradience, albedo (ration of radiation absorbed to reflected) and the insulating properties of the atmosphere which varies according to composition. This was a dynamic system which oscillated wildly with positive and negative feedback loops.
With the advent of large scale biology additional feedback loops arose that had the effect of stabilising the climate.
Vulcanism (generating dust in the atmosphere), geological subduction (recycling of carbonates again through vulcanism) and variations on solar output and mean orbital radius shifted the equilibrium from time to time.
As with any regulating system biology (mostly plants) can only cope with a certain degree of disturbance. The human emissions of CO2 for much of the last 200 years was within the level that the biosphere along with oceanic absorption could cope with. In recent decades atmospheric CO2 has pushed the regulating mechanisms beyond capacity and the result has been a rapid rise (in geological terms) of global temperatures.
To go back to the original question (with all that has been done so far must contribute to reducing the weather?):-
What has been done so far is to reduce the rate at which CO2 is increasing in the atmosphere with the ambition of halting net additional CO2 by 2050 or before. This has already 'baked in a probable rise in temperature of 3 to 4 degees by 2100 at which point, hopefully we get to a new equilibrium. We are already at around +1.5 degree's. In order to reverse the rises our only lever is to draw down CO2 and there are currently no large scale methodologies of doing that although people are trying. So with what has been done so far we hopefully will succeed in slowing the rate at which things are getting worse and with luck end up in a situation which is survivable
Getting rid of the bit coin miners would be a start.
Current estimates are that Bitcoin is using around seven gigawatts of electricity, equal to 0.21% of the world's supply. That is as much power as would be generated by seven Dungeness nuclear power plants at once.(3 Jul 2019)
Well whatever anyone 'chooses' to believe they had better hope that climate change is man made, because if it's not we have no way of doing anything about it and it's goodnight nurse.
It is. I just thought it was interesting how one goal can pull in the opposite direction to another.
Edited By Martin Kyte on 24/02/2020 13:33:17
The phasing out of soft house coal is interesting as an example of conflicting aims. Coal is a hydrocarbon and the various grades of coal are largely defined by the carbon/hydrogen ratio. When burnt part of the heat out put comes from Carbon and part from Hydrogen and other volatiles. Heating coal in the absence of oxygen produces coke and town gas (hydrogen(50%),methane(35%),carbon monoxide(10) and ethylene(5%)) of which the hydrogen at around 50% merely produces heat and water so is quite environmentally freindly.
It is clear to see that the more volatiles in the coal the less CO2 will be produced for the same heat output as more heat will come from hydrogen, methane and ethylene and less from pure carbon. So as far as CO2 is concerned banning soft coals and burning anthocite coals will increase the CO2 output assuming the number of coal fires stays the same.
Soft coal however produces more pollutants in the average domestic hearth. Open fires are not brilliant at complete combustion and a lot of the soot and ash particulates are sent up the chimney with no filtering or any other clean up so in order to improve air quality smokeless coal is better.
So you pay's your money and takes your pick, either less CO2 and more air pollution or more CO2 and cleaner air.
Personally I think that the CO2 output trumps everthing at this point in time.
As an additional comment, we may be better to return to town gas with it's nice clean 50% hydrogen rather than the high methane Natural gas we use today.
|Thread: Four Jaw chuck|
One of my most used 'tools' is a sprung (spring?) centre which makes setting up to a centre pop/centre hole very straight forward in the 4 Jaw. Easy to make too. I also have a dial guage that lives in a QC tool holder which also saves faffing around. Never bothered with a second chuck key.
|Thread: Effect of Tensioning a Boring Bar|
My point was that the prestressing of concrete was not an attempt to increase stiffness or stop vibration but to ensure that the beam remained in compressive load. As you correctly say the force vectors are the same albeit with the sign change.
ummm, I think so. If you have a linear strees strain curve and preload puts you somewhere on the curve additional loads will still cause the same magnetude of extension or compression as without preload. Concrete beams are a bit of a red herring as the object is to ensure that all loads are compressive as far as possible.
I don't think the answer will be found in static deflection analysis but only by considering the dynamic system.
Boring bar chatter as far as I can make out, (and I do not set myself up as an expert in this field) appears to be be primarily modal rather than regenerative in nature. By this I mean that the bar bends into and out of the cut and also twists one way and t'other, with the tool tip oscillating in an elipse. I do not have the ability to do the maths but intuitively I can buy into the tensioning of the bar having an appreaciable effect on the energy transfer between the two modes of oscillation by causing the natural frequency of the two modes or oscillators to be non harmonic and thus making the dynamic stiffness or maybe resillience would be a better word? increase.
I do however note Graham's results on static tests which have not really been explained. Maybe the tesioned bar is twisting as well as bending as the load is applied. I don't know.
|Thread: Adjusting an M&W level|
Is this any help.
I would have thought that the level adjuster(s) should be at 90 deg to the hold down screws and should act by inserting or withdrawing a tapered seating. You don't need a perfectly level surface to test it so long as it reads somewhere withing the scale. Just mark the initial position and rotate by 180 degrees for a second reading. They should be identical when perfectly adjusted.
|Thread: Linked belt for Myford 7|
There is a right way round you know with these belts. Maybe that's why some find they slip.
1 pair of contacts normally open and 1 pair normally closed.
Wire the pair you want.
|Thread: marine steam engines|
There you are look, worse things do happen at sea !
Used to be a single size gas mantle, before that it was just a flare. Even oil lamps had different sized wicks.
You could always go back to candles or even just go to bed when it gets dark.
|Thread: Encryption software|
It's interesting to find out how fast a computer can crack your passwords these days.
There are a number of 'online password testers' available, don't use live one obviously.
Here are 4 examples.
6%#863 - 6millisecs
blooge3 - 2 secs
railSTEELtell - 16 thousand years
railSTEELtell1@ 16 billion years
The third example is good and interestingly the easiest to remember. Often sites will insist on some numbers and other characters also so I added 1@ which doesn't really make it that much harder to remember.
The construction is from Floyd's lyric on wish you were here. Pick a phrase/verse or lyric. Extract 3 words capitalise one of them and add some numbers/other characters.
Weak passwords are worse than useless, tough passwords do not have to be hard to remember.
|Thread: Effect of Tensioning a Boring Bar|
Very interesting. Effectively the rod down the middle of the bar has added another degree of freedom allowing resonant motion at two different frequencies.
So maybe the best way of thinking about the tensioned bar is as two coupled oscillators something along the line of 2 pendulums of dissimilar length both hanging on a line which couples them togather. Energy will be transferred back and forth from the one to the other at at the beat frequency in a similar way to the employment of tuned mass dampers for tall buildings etc (google it).
This company actually produces a tuned mass damper boring bar.
I don't think for a minute that the simple tensioned bar we have been discussing approaches a tuned system however the addition of the tensioned rod certainly seems to have the effect of disrupting the single frequency simple oscillation.
I did try and find a video of coupled pendulums of different lengths but so far have failed.
|Thread: cylinder boring|
That fits with the philosophy of protecting the investment you have already made either in money or time. Retain as many second chances on high value components as you can.
|Thread: I just had to buy this|
Were the three wise monkeys the personification of design, production and quality depts?
|Thread: New from the edge of the Fens|
Aha, perfect timing Ian. I have just the project for you, Marham are offering their Victor gate gardian free to a good home to anyone who promises to restore it.
Could be an ideal starter project and as has already been said you have the ideal skills.
Welcome to the madhouse anyway.
|Thread: cylinder boring|
. . . . or which do prefer to scrap the piston or the cylinder. Not that any of us get it wrong :O)
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