John Cuthber

2 hours ago, mistermack said:

I doubt if you would have much success grafting a pear onto apple rootstock or vice-versa. It might survive for a while, but I doubt if it would be successful long-term.

I don't see why it couldn't work.
They commonly use quince stocks for pears
https://www.orangepippintrees.co.uk/articles/fruit-tree-gardening/rootstocks-for-pear-trees

The root stocks are also propagated from cuttings- for the same reasons as the  top bits.

I gather that you can graft pears, apples and quinces onto the same tree.

I'd like to know if you can do it with these fairly closely related plants
https://en.wikipedia.org/wiki/Buddleja_davidii

and
https://en.wikipedia.org/wiki/Buddleja_globosa

Because the clash between the  orange and purple flowers would be hideous.

Those trees are almost certainly grown from cuttings.
The word "heirloom" in this context means that they are a very old variety.

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

I think it was assessed here

And the consensus was that it's crazy.

I don't  think there has been any improvement since.

17 hours ago, Externet said:

 

How do I calculate its rating ?

 

To a good approximation, weigh the jack.
Find jacks of similar design on the net and then look for one that weighs the same.

I'm pretty sure someone has the maths for things with a smooth change in refractive index.

https://en.wikipedia.org/wiki/Gradient-index_optics

On 11/2/2023 at 9:05 PM, Alfred001 said:

???

That's what we'd debated for two pages. You claiming no effect exists or is so small as to not matter, me saying that, as the paper says, there's inadequate evidence to know how big the effect is.

I did not say that no effect exists.
I said that if there was a big effect, we would know about it.
 

1 hour ago, mistermack said:

You could just kit it out with an Alexa, and train it to stop on the word "stop". The hard part would be to train the staff to never say stop within earshot. 

If you didn't allow any people near the robot, you wouldn't need to worry about them saying "stop".
A policy which may have other benefits...

1 hour ago, toucana said:

I found myself wondering quite what sort of robotic sensor you would use to reliably distinguish between a human being and a box of vegetables ? The best candidate I can think of is a FLIR (Forward Looking Infra-Red) camera.

In this situation, you could use a passive IR sensor like they use in burglar alarms.
If there is a person in the room, you shut down the robot.

1 hour ago, Sensei said:

Hook's law is/was taught first. I would say, it is stupefying people..

Is that why you answered a post on double displacement reactions without there being anything related to double displacement reactions in your reply?

2 hours ago, toucana said:

From the second article cited in my OP:

"In addition, overcharging a lead acid battery can produce hydrogen sulfide gas. This gas is colorless, poisonous, flammable, and has an odor similar to rotten eggs or natural gas. The gas is heavier than air and will accumulate at the bottom of poorly ventilated spaces."

https://ehs.umass.edu/sites/default/files/Battery SOP.pdf

see also:

"Under normal operating conditions, the gasses evolved are hydrogen (H) and oxygen (O). However, under extreme conditions other gasses may be produced such as hydrogen sulphide (H2S). Some strange gasses are also given off in very small quantities such as carbon dioxide (CO2). This document only considers the evolution of hydrogen, oxygen and hydrogen sulphide."

https://www.blueboxbatteries.co.uk/blog/industrial-battery-gassing-37

I also came across one news report from USA where people were found dead in a car. It was initially thought they had suffered from carbon monoxide poisoning, but forensic tests showed they had  died from hydrogen sulphide poisoning from a lead acid car battery that had been shorted out by a defective starter motor.

 

And here is an exhaustive academic study commissioned by the US Navy in a 2002 review of SEAL (Submarine Escape Action Levels) for hydrogen sulphide contamination in submarines, which discusses trigger thresholds for emergency action to be taken in response to the detection of levels as low as 10 to 15 PPM of this gas:

https://nap.nationalacademies.org/read/10242/chapter/9

If your batteries are nearly on fire you will get some H₂S.
The academic book doesn't seem to mention batteries.

I'm reminded of the  story of the Kursk, where the official news said lots of things...

 

24 minutes ago, toucana said:

The hydrogen sulphide (H2S) probably came from a malfunction in the charging and venting system of the submarine’s heavy duty lead acid battery system which typically uses lead alloy plates in an electrolyte solution of 35% sulphuric acid and 65% water.

That does not make much sense.

5 hours ago, Alfred001 said:

However, due to inadequate epidemiological evidence, it is not considered as a risk factor for cancer in humans.

That's not true.
It is considered as a risk factor in humans
https://en.wikipedia.org/wiki/Metronidazole

says 

"In 2016 metronidazole was listed by the U.S. National Toxicology Program (NTP) as reasonably anticipated to be a human carcinogen."

and "Metronidazole is listed as a possible carcinogen according to the World Health Organization (WHO) International Agency for Research on Cancer (IARC)"

It plainly is considered to be a cancer risk.

Similarly
 

5 hours ago, Alfred001 said:

however it is still controversial in humans.

Says who?
That paper is from 2018 by which time MTZ had been listed as a carcinogen for 2 years or so.


Is anyone saying it's not carcinogenic?

 

41 minutes ago, kenny1999 said:

Without seeing a doctor,

No.

The National Trust is responsible for some bits.
 

2 hours ago, swansont said:

I don’t think this is being proposed as a replacement for natural gas.

I do, and it's not just me.
https://www.keele.ac.uk/sustainable-futures/ourchallengethemes/providingcleanenergyreducingcarbonemissions/hydeploy/

We use billions of tons of natural gas each year.
Mining "between 6 million and 250 million metric tons of hydrogen" isn't much use.
 

1 hour ago, swansont said:

They ran calculations and estimated the deposit could contain between 6 million and 250 million metric tons of hydrogen”

We use something of the order of billions of tons of natural gas each year.
Taking the geometric mean of their estimates means that known hydrogen reserves would run out sometime between Xmas and Easter if we used them at the same rate.

I wonder if people engaged in this know what the death tolls on each side look like.
This may clarify it
(It obviously only includes civilians)
https://countingthekids.org/?fbclid=IwAR0rsRw5R5C0yBNhvKy7_eHdasFiJpkJ0J1L85h8BIKvkKgHyhzLgI2py-4

1 hour ago, geordief said:

if you marinate your meat, cancer risk can be decreased by as much as 95% because it creates a barrier to high-temperature cooking

Is there any evidence of that?

29 minutes ago, studiot said:

This will be after radically removing the 'planning' from the planning process,

That's what the Tories did.
They transferred planning responsibility to a cheat.
https://www.insidehousing.co.uk/news/news/jenrick-steps-up-threat-to-council-with-ultimatum-over-local-plan---64679


 

Their man is "Going to build 5 new towns in the next couple of years to solve the housing crisis".

How ? 

Probably better than the last guy built 40 hospitals
https://www.theguardian.com/society/2023/jul/17/government-on-track-to-break-boris-johnsons-40-new-hospitals-promise

42 minutes ago, mistermack said:

Seventy years ago, there were butterflies everywhere. The downside was that their caterpillars would destroy my dad's garden.

He would fight a running battle with them, dusting everything with Derris Dust, which was cheap and effective. (DDT) 

I don't think it did us any harm, eating food that came from plants that were white with DDT. All seven of us kids are still here. 

But I miss the butterflies, and the skylarks overhead. 

Derris is not DDT.
https://en.wikipedia.org/wiki/Derris
It contains 
https://en.wikipedia.org/wiki/Rotenone
Which is often up forward by environmentalists as "good".

"Soil Association standards allow organic farmers restricted use of seven nonsynthetic pesticides that have been approved on the basis of their origin, environmental impact and potential to persist as residues. They are copper ammonium carbonate; copper sulphate; copper oxychloride; sulphur; pyrethrum; soft soap and derris (rotenone)."
From 
https://www.soilassociation.org/media/4920/policy_report_2001_organic_farming_food_quality_human_health.pdf

It's associated with parkinsonism.
https://en.wikipedia.org/wiki/Rotenone#Parkinson's_disease

 

We used to rely on mulching, hand weeding and "bio controls"- whatever they may be.
They weren't good enough. That's why we started using weedkillers.
Glyphosate may be carcinogenic, but so is alcohol and that doesn't stop people using it.
It's a risk/ benefit question.
Only presenting the risks is dishonest.

It's a commonplace observation that "if you drop a knife, you should let the floor catch it".
If that's an option, it can't be a reflex- they are fast but unsophisticated.

Here's what you said, and what you said it in response to.
 

You asked what does it have to do with escape velocity and I explained why part of it has something to do with escape velocity.
I said "The escape velocity isn't strictly relevant, but it's a proxy for gravitational energy."

On 10/11/2023 at 10:54 AM, John Cuthber said:

The escape velocity isn't strictly relevant, but it's a proxy for gravitational energy.
Essentially you "drop" your spacecraft towards the sun and it accelerates as it goes.
If you don't fire retro rockets to slow it down, it hits the sun.
It takes pretty much as much fuel to get something "down" as it does "up".

And you ignored that and focussed on this bit.
"If you don't fire retro rockets to slow it down, it hits the sun."
 

8 hours ago, Sensei said:

.and so what? It's a one-way mission anyway, because of what I said earlier. It will melt down..

Repeating your unproven assertion that you can't put something in orbit near the sun- well, in reality it depends in how near you get- but that's beside the point.

But the answer to "so what?" is still that  escape velocity- or gravitational potential energy- is important to the idea of putting something in orbit round the  sun (As Halc said)- even if the thing melts.



 

1 hour ago, Sensei said:

When someone says A and B, and A refutes your claims and B confirms them, you brazenly ignore what is in A

You brazenly  ignored part of what Halc said and bolded part of it, didn't you?
 

Tell the site software.
You did, in fact, say it.
You were quoting Halc.
 

25 minutes ago, Sensei said:

Do you read what you quote?

Yes
 

26 minutes ago, Sensei said:

let alone actually go into low orbit around it,