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Just Chat! / Why do women have so many clothes?

« on: 28/09/2024 20:15:38 »

The sheer quantities of clothing items the boss has collected over the years we have been together is baffling. New items are constantly added to this already voluminous collection with some items hardly worn at all. I have pointed out the wastefulness of such a practice with the response being "you are male and don't understand". I wonder what the latter day philosophers(such as the eminent Alancalverd!) think of this predicament.

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Just Chat! / Exploding batteries or not?

« on: 17/09/2024 17:49:58 »

Watching the news about the exploding pagers in Lebanon I see some nonsense being disseminated. So called defence "experts" are suggesting this was done by software to short the batteries and having seen some of the blasts I discount this. This was obviously carefully planted explosives, assuming the batteries involved don't use ethyl perchlorate as solvent!

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Just Chat! / Where is Hamdani?

« on: 04/09/2024 19:40:11 »

As the title suggests I have not seen a post from Hamdani today. I did not believe this was possible. Hope he is ok. Indonesia is seismically active and prone to disasters. PS I was in southern Portugal last week and woken up ~5.30am with the bed shaking slightly and the doors rattling- my first earthquake!

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Plant Sciences, Zoology & Evolution / Where have all the bugs gone?

« on: 23/08/2024 11:10:36 »

We live in a rural location in the middle of a forest and have been here for~30 years. Previously(10 or more years ago) in July and August we would be inundated with all kinds of weird and wonderful bugs and critters. Not anymore, the last few years have witnessed a dramatic decline. For example we used to see cinnabar moths every year but no longer. We had several swallow families regularly breeding in an outbuilding and these have ceased, presumably due to lack of food. I should also point out that we practice rewilding over a large portion of our .75acre.

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That CAN'T be true! / Is potassium chloride explosive

« on: 20/08/2024 13:24:03 »

Of course not, but bear with me. Recently the boss had the gogglebox on but was not watching it- it was running a programme called "abandoned engineering" on one of the freesat channels. I watched it for a short while and was absolutely gobsmacked by what I heard. An educated gentleman(an archaeologist I think but could be wrong) stated that potassium chloride was madly explosive which was popular with terrorists and was the reason for the extreme danger of potash mines!! I can only think he meant potassium chlorate but this is a man made substance and is definitely not a mined product- abandoned mines was the subject matter. If I was to pontificate on a subject I was not familiar with I would at least do some research first.

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Just Chat! / Is there any greater ******** than Elon Musk?

« on: 07/08/2024 18:28:59 »

With Musk's recent remarks concerning the riots in the UK, I believe he has become the greatest plonker that I am aware of. I am also beginning to think he has "a leak in his attic", an expression used by the late Rod Serling in the twilight zone(a series of surrealistic short stories on tv circa 1960).

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Science Experiments / A report: may be of use to someone?

« on: 07/08/2024 08:17:24 »

My eldest daughter had a flimsy white garment(cotton/synthetic mix) that she intended to use in a charity event but which had a nasty rust stain which seemed indelible and I was asked to remove said stain. My first idea was a sequestrant acid such as edta, nta or atmp but not having any of these I thought maybe citric acid would do the job but this failed miserably. A rethink was needed: from the colour I reckoned it was ferric iron and maybe a reducing agent would return it to the ferrous state whereby it would dissolve in dilute acid. Hydrazine hydrate and sodium dithionite came to mind but again I have neither. I decided to try sodium metabisulphite, sprinkling some over the stain and adding a few drops of water. I left this sit for several hours but again it seemed to have no effect and I intended to rinse the garment out and give up. Fatigue overcame me and I forgot to rinse the garment out and to my surprise next morning the stain had disappeared. A note of caution: this was a white garment and attempting to use this method on a coloured item may cause damage to the dye.

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Just Chat! / Is social media compromising civilisation?

« on: 24/07/2024 10:21:56 »

I am not on social media, never have been and never will be. I am stunned by the amount of hatred spewed out by the so called "keyboard warriors". Even news events that are entirely noncontroversial seem to trigger the outpouring of venom. Recently a young man lost his way in Tenerife and died tragically and this story apparently led to some foul on-line correspondence. Personally I think social media is destroying the cohesiveness of society.

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Just Chat! / Can anyone help to give a mental construct of a vector function?

« on: 03/07/2024 11:11:02 »

In electromagnetics the following identity is very useful: ∇x∇xA=grad(divA)-laplacianA. Things like divergence, curl and gradient are easily visualised as outflow, rotation and directional rate of change but I cannot visualise the "curl of a curl of a function". I need a mental visualisation or construct to get a full understanding but I realise this is not always possible as some maths is too abstract to enable a mental picture. Any thoughts?

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Just Chat! / Fed up with the lack of reasoned discourse

« on: 28/06/2024 04:57:59 »

Increasingly these days when I make a point on any subject I get a reply which consists of computer generated claptrap rather than a reasoned argument from a thinking conscious entity. I find this infuriating, maybe i'm just too old.

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Just Chat! / What keeps a bicycle stable in the vertical orientation?

« on: 25/06/2024 09:56:16 »

Is it the gyroscopic effect of the wheels or fine motor control of the rider?

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Just Chat! / Is the ever increasing energy density of lithium batteries a major hazard?

« on: 12/06/2024 08:11:34 »

My car holds~20kg of petrol(gasoline). This quantity of hydrocarbon, when combusted stoichiometrically with oxygen, yields the same energy as 200kg of tnt. Now taking the efficiency of the engine as 33% the quantity of fuel actually propelling the vehicle is ~6kg. To replace this with a battery one ends up with a stored energy equivalent of ~60kg of tnt. The destructive power of tnt lies in it's ability to release all it's energy virtually instantaneously and this scenario is unlikely to happen with a hydrocarbon fuel except in an extremely violent collision. A battery can in theory release a large portion of it's energy in a short time. Some of the lithium ion battery failures I have seen are extremely violent. Is this hazard being taken seriously enough, especially with the push for ever higher energy densities? 

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Just Chat! / What is the best system to provide for consumers, private or state owned?

« on: 08/06/2024 10:33:47 »

Alancalverd argues against privatisation of services, with good reason as profit becomes the chief criterion and the consumer suffers. On the other hand state supplied services can become centres of mediocrity, where no one can be sacked for failure, there is no motivation for improvement and the state is seen as a bottomless pit of cash. I must emphasise I am talking about experiences in my native country, Ireland. It may be different elsewhere but I doubt it. One major example here is the health service: over the years enormous quantities of money have been thrown at it and yet it is falling apart with an exodus of qualified professionals. No one has the guts for a slash and burn reform process which would be the only way of saving it. I don't have any magic solutions but I do know that in the absence of some sort incentive to improve, work expands to fill the time allotted.   

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Just Chat! / Squirrels invading my attic, what should i do?

« on: 03/06/2024 14:44:09 »

I have a problem with squirrels invading my attic. I have sealed up any gaps I can find but they still get in. These are the rarer red squirrels which have been making a comeback in this area. Because of their endangered status we regularly feed them with peanuts and I realise this could be encouraging them. I am not prepared to do anything that may harm them, in any way - it's illegal to do so, anyway. For a while the placing of soiled cat trays in the attic frightened them away but they seem to have developed immunity to this tactic. 

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Just Chat! / What the hell is being put in joss sticks?

« on: 29/05/2024 09:11:18 »

Yesterday the boss headed into Dublin with the express intention of wasting as much of my good money as possible(retail therapy, I believe is the term). After this attack on my accounts she comes home with a collection of rubbish and some joss sticks. I am well used to these sticks being used and generally I have no problem but occasionally a particular type will be unpleasant and I request that she desists. None of my previous experience prepared me for what happened yesterday. Two sticks were lit and a short time later both our eldest daughter and me began to suffer throat irritation which got worse and worse and eventually required the opening of doors and windows to vent the noxious fumes. The sensation was akin to that which occurs when a large quantity of chillies are being finely diced and capsaicin becomes airborne. The boss was not affected. Our daughter has several allergies but I have none that I know of.

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Physics, Astronomy & Cosmology / Why does an mri magnet not radiate em?

« on: 24/05/2024 20:18:21 »

Any electron following a circular path is accelerating and accelerating charges radiate. Why no em radiation from electromagnets? I only used the mri as an example of a rather extreme electromagnet. A comment by Hamdani triggered this query.

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Physics, Astronomy & Cosmology / What empirical evidence led to Einstein's choice of postulates for SR?

« on: 20/05/2024 20:41:14 »

Right, i'll have a go. My question concerns the historic break with the Newtonian paradigm around the time when relativity was developing(SR). The speed of light,(1) radiating from a moving object and (2) impinging on a moving object are decreed by SR to be exactly c, regardless of the speed of the object. (1) does not, in my opinion, require any postulate from relativity: once emitted the speed of the radiation will be determined solely by μ and ε. (2) However conflicts with Newton as one would imagine that the speeds would be additive/subtractive. What experiments/theory led to the conclusion that light impinging on a moving object at any arbitrary speed( <c) would always arrive at c? I have struggled with the wording of this question and am still not satisfied with it. 

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Just Chat! / What to do if your question is too long to fit in the title bar?

« on: 17/05/2024 19:56:08 »

I have a question, in physics, that I cannot condense sufficiently to fit in the title bar. Any suggestions?

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Technology / Does regenerative braking have a hazardous complication?

« on: 23/04/2024 17:36:38 »

Driving the boss' car(hybrid), as my own has expired, I have noticed some concerning behaviour.(1) When I lift my foot off the throttle pedal the car slows down more rapidly than a non hybrid due to regenerative braking. (2) Moving the selector from D to B one can achieve much greater retardation through an enhanced regenerative process. All well and good as regards fuel economy but neither function appears to activate the rear brake lights such that a driver following would be missing the required visual cue. Unless the lights are activated at a certain speed- I was driving along our ~30m driveway watching for reflection off a window and my speed was obviously quite limited.

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Just Chat! / Will be incommunicado for ~9days

« on: 22/03/2024 14:45:24 »

As the title says I will have no access to the net for just over a week. I know you will all miss my words of wisdom but please be patient I will return after I have sorted out my parole officer(joke!!).