Member postings for Michael Gilligan

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As will be clearly demonstrated by the example of two pendulums mounted on a substantial beam gradually synchronising.

[ sorry, can’t remember whom to credit ]

MichaelG.

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 … it was my hero:

https://physicsworld.com/a/the-secret-of-the-synchronized-pendulums/

Edited By Michael Gilligan on 03/09/2023 21:21:44

[assuming that you are still considering a rodded pendulum]

Similar, Yes … but that alone is not sufficient to make the pendulum isochronous.

MichaelG.

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Incidentally; just for clarity … can you explain why you describe your roller arrangement as a ‘knife-edge’ … it seems to be anything but.

Edited By Michael Gilligan on 03/09/2023 20:48:53

Get that vacuum pump going, Jo

MichaelG.

Nice one, John

MichaelG.

It never rains but it pours, they say:

[quote] Experts warn that the presence of RAAC also increases the danger of exposure to asbestos, which kills 5,000 people a year in the UK. Asbestos is safe while stable but if it is disturbed — for example, if a classroom roof made from crumbling concrete suddenly collapses — it could release fibres which can cause mesothelioma, asbestosis and lung cancer. Even removing or assessing RAAC panels could disturb asbestos, engineers said.[/quote]

From the Sunday Times

MichaelG.

Fans of Dan Gelbart might recognise the principle of this one:

**LINK**

https://www.huberlab.org/resources/optical-alignment-device/

MichaelG.

John,

You are probably right to identify the different mechanisms by which the water ingress starts, but the ‘bursting’ mechanism is similar for both products … Rust has a bigger volume that the metal it replaces.

MichaelG.

I will try, Dave … but it repeats things I have already mentioned, and l think your mind-set is currently different.

Please look carefully at Huygens’ description of how to construct the cycloid and [crucially] note that his style of pendulum does not use a rod … it is flexible.

Your 2p version works as a little self-contained mechanism … but extending it with a stiff rod will not.

MichaelG.

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Edit: __ Here, in case you didn’t find it earlier, is a link to Ian Bruce’s translation:

https://www.17centurymaths.com/contents/huygenscontents.html

Edited By Michael Gilligan on 03/09/2023 06:59:31

Evidently .. the Science continues: **LINK**

https://www.sciencedirect.com/science/article/abs/pii/S2352710221009645

MichaelG.

This Wikipedia page about AAC is worth a look: **LINK**

https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete

and it includes a link to the RAAC page.

MichaelG.

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P.S. __ This page [which is linked from the above] provides a history of the development of AAC

https://web.archive.org/web/20101104001651/http://www.hebel.co.nz/about/hebel%20history.php

Edited By Michael Gilligan on 03/09/2023 04:38:29

You’re welcome, Andy

I shall be very interested to see how you get on, if you decide to use them.

MichaelG.

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Yes in principle … but the special feature is that this stuff has similar structure to a Crunchie bar in the first place.

MichaelG.

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Image credit is in my album.

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Edited By Michael Gilligan on 02/09/2023 17:56:50

Very interesting, Dell

Do keep us informed how it goes.

MichaelG.

Whatever your coefficient of lunacy might be, Iain … You deserve to get some decent results after all that effort !!

MichaelG.

That all looks fine to me [as far as it goes], Dave

But John did mention ‘straight line’ earlier … which is what I was picking-up on

Have a look at the page I linked last night: **LINK**

https://serc.carleton.edu/sp/library/teachingwdata/graphsexponential.html

and click on the first two of the three big yellow pictures to enlarge them.

That’s what a straight line should look like 

MichaelG.

Edited By Michael Gilligan on 02/09/2023 12:12:30

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Fine, if you say so, Clive

Having used my J&S version of the Nippy for nearly 40 years now perhaps I was being overly critical

… it’s just so much easier if things are better designed and better built.

MichaelG.

If the description is to be believed … You have probably bought a reasonably priced set of castings there, Jon

**LINK**

https://hurst-iw.co.uk/products/eclipse-drill-press-vice-4in-100mm

I suggest you find a more suitable vice for immediate use, and treat this one as a ‘project’ in due course.

MichaelG.

Too late to re-edit that untidy post

MichaelG.

I am very rusty on this stuff, Jo … but I think you might want to use the natural logarithm:

**LINK**

https://youtu.be/mUfXkwTQB8o?feature=shared

This looks like a good tutorial … I’m off to get a drop of Jura

MichaelG.

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Edit: __  Try here: https://serc.carleton.edu/sp/library/teachingwdata/graphsexponential.html

Edited By Michael Gilligan on 01/09/2023 22:06:39

You might want to look a little deeper, Andy: **LINK**

https://www.slamcity.com/pages/hard-skateboard-wheels-vs-soft-skateboard-wheels

… or maybe not

MichaelG.