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John Cuthber

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Posts posted by John Cuthber


  1. 16 hours ago, Airbrush said:

    Any volunteers for this analysis?

    "Step right up folks!  Come into my new business (restaurant, offices, stores, markets, Disneyland, etc.) and enjoy AAR (accelerated air replacement).  My competition has poor, weak A/C that just pushes the air with virus around for an hour before it finally slinks out the ceiling.  That gives you plenty of time to get infected right thru your cloth mask.  My business, however, has fresh air ALL THE TIME for you to enjoy!  We have extra powerful fans to move the bad air out and good air in."

    My analysis is that you just invented the pavement cafe.

     


  2. "Is that the kind of example you want people to follow" is a question about epidemiology, not politics.
    It's obvious that the scientists, like any sensible people, would say "No, it isn't".
    That's got nothing to do with politics. There would have been no loss of "impartiality"  involved in answering it.


    But Boris didn't let them answer because it made his friend look like an idiot.
     


  3. It's certainly odd. I'd have expected the opposite effect.
    I can think of one possibility.

    If the unfiltered juice contained intact cells and those were broken during the filtration process then it's possible that their contents were less conductive than the surrounding liquid.
    That's possible, but seems unlikely- I'm not sure how you would test it.
     

    Does it get hot during filtration?

    Is it being filtered on an industrial scale- could you try with a smaller rig- say a laboratory scale  with a flask, funnel and filter paper?


  4. It might be worth explaining the bizarre unit- the "inch of vacuum".

    It is, as I said, like trying to describe the thickness of a coin by measuring the difference between that thickness and the width of your thumb.

    The original idea was fairly simple.
    You got a mercury filled barometer.
    http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/statics/node15.html,

    Then you connected the top of it to your apparatus.

    The better your pump was, the more it pulled the mercury up.

    And if your use for a pump was pulling water out of a mine shaft, that's probably as good as it needed to be. You could pull water roughly 13 times further , because it's 13 )or so) times denser than water.

    The problem is that the pump doesn't pull the mercury up- the atmosphere pushes it up- and the atmosphere is variable..
    Well, that's still OK if you need to know if your pump is pulling water out of a mine, because the head of water is also affected by the atmosphere.

     

    But, if you want to get a reasonably accurate measurement, you can't use the atmosphere as a reference point. (OK, technically, you can- if you measure it accurately).

     

    If the actual atmospheric pressure varies by an inch of mercury, that isn't going to make much difference to the mine pump. A change between 20 inches and 21 isn't worth worrying about.
    But, if you are actually working with a pressure  that's less than an inch of mercury, your "reference" point varies so much that you can't tell if your pressure is positive or negative (well- it' can't really be negative, but that';s what the gauge.would show).

    None of that will actually help answer the OP's question.

     

    Because the question is like saying "my antique clock keeps time to +/- 30 minutes a day. IS that good enough?"


    Good enough for what?

    If the OP ever actually tells us what question they want to answer, we might be able to answer it.

     


  5. 13 hours ago, Theredbarron said:

    my original question is how important is the difference between 29 and 30! someone answered it and some just tried to ask about my setup.

    And the answer is that it depends what you are trying to do. How did you imagine that we could answer the question without knowing that?
     

     

    12 hours ago, Strange said:

    As I think others have said, trying to express a vacuum as 30 inches of Hg isn't terribly meaningful or useful. It is a bit like asking about the thickness of a piece of paper in miles

    It's worse than that. It's like asking how thick a coin is by expressing is as "How much thinner than a thumb is it?".
     

     

    15 hours ago, Theredbarron said:

    So pretty much not going to get to 30 with standard equipment? or would digital be any benefit like sensors versus mechanical even if im not making it to 30?

    Which part of "impossible" did you not understand?


  6. 7 minutes ago, Theredbarron said:

    No one listens to what I type about what im doing and some tend to simply pretend that im not doing this in speculations. So I would but moving matter without touching it is what im describing it as and I wanted to do it in a vacuum as far as I can with what resources I have. What I want to know is how much does it really in space or anywhere matter that one inch. only because my setup wont pull that on my guage and if I need to upgrade it would be because that one inch difference has more importance then lets say 15 to 30.  

    If the atmospheric pressure is the so called "standard" of 760 mmHg it is impossible to get 30 inches of vacuum.


  7. If you are an insect in the jar  it matters very little- you are dead either way. Both are far too low..

    If you are trying to do things that need a good vacuum- like build a mass spectrometer, there's no meaningful difference between 29 inches of vacuum and atmospheric pressure.

    Both are millions of  times too high

    4 minutes ago, Theredbarron said:

    . I didnt think it was that hard of a question.

    Well, do you now realise that you were wrong?


  8. OK Thredbarron,

    It's going to work better if you start at the beginning.
    I doubt that you woke up one morning and thought "Just for kicks, I will hook a vacuum pump and gauge to a jar".

    What are you trying to do or find out?

     


  9. 7 hours ago, studiot said:

    I just have this vision of a poor little groundsman staggering along with a thousand gallon tank of ethanol on his back.

    I just hope he doesn't smoke.
    Seriously, the question needs more context.

    Over what time scale, and what area are you  using the alcohol?
     


  10. We are on a planet made of matter. It is in a universe full (largely) of vacuum.

    What observations were you hoping to make about the jar that you can't make much more simply about the Earth?

     

    1 hour ago, Strange said:

    How much difference does it make to what?

    It is roughly equivalent to being 1,000 feet above sea level. It will reduce the boiling point of water by about 1º. Does that help?

    Except it's the other way round.
    This is one reason why inches of vacuum is a stupid unit.

    He has removed roughy 29/30 of the air.

    So the pressure is roughly 1/30 *750 mm Hg
    About 25mmHg
    Water will boil in that jar at about 27C

    The other reason why it's a lousy unit is that it literally depends on the weather.


  11. On 5/20/2020 at 12:38 AM, DrP said:

    It's similar here across the pond...  many are suggesting we 'clap for Boris' and any criticism of him is unfair...  here is his timeline of events in response to the crisis:

    Timeline:

    December 31st China alerts WHO to new virus.

    January 23rd Study reveals a third of China’s patients require intensive care.

    January 24th Boris Johnson misses first Cobra meeting.

    January 29th Boris Johnson misses second Cobra meeting.

    January 31st The NHS declares first ever ‘Level 4 critical incident’ Meanwhile, the government declines to join European scheme to source PPE.

    February 5th Boris Johnson misses third Cobra meeting.

    February 12th Boris Johnson misses fourth Cobra meeting. Exeter University published study warning Coronavirus could infect 45 million people in the UK if left unchallenged.

    February 13th Boris Johnson misses conference call with European leaders.

    February 14th Boris Johnson goes away on holiday. Aides are told keeps Johnson’s briefing notes short or he will not read them.

    February 18th Johnson misses fifth Cobra meeting.

    February 26th Boris Johnson announces ‘Herd Immunity’ strategy, announcing some people will lose loved ones. Government document is leaked, predicting half a million Brits could die in ‘worst case scenario’.

    February 29th Boris Johnson retreats to his country manor. NHS warns of ‘PPE shortage nightmare’. Stockpiles have dwindled or expired after years of austerity cuts.

    March 2nd Boris Johnson attends his first Cobra meeting, declining another opportunity to join European PPE scheme. Government’s own scientists say over half a million Brits could die if virus left unrestrained. Johnson tells country: “We are very, very well prepared.”

    March 3rd Scientists urge Government to advise public not to shake hands. Boris Johnson brags about shaking hands of several people in hospital with Coronavirus patients.

    March 4th Government stops providing daily updates on virus following a 70% spike in UK cases. They will later U-turn on this amid accusations they are withholding vital information.

    March 5th Boris Johnson tells public to ‘wash their hands and business as usual’.

    March 7th Boris Johnson joins 82,000 people at Six Nations match.

    March 9th After Ireland cancels St Patrick’s day parades, the government says there’s “No rationale” for cancelling sporting events.

    March 10th - 13th Cheltenham takes place, more than a quarter of a million people attend.

    March 11th 3,000 Atletico Madrid fans fly to Liverpool.

    March 12th Boris Johnson states banning events such as Cheltenham will have little effect. The Imperial College study finds the government’s plan is projected to kill half a million people.

    March 13th the FA suspends the Premier League, citing an absence of Government guidance. Britain is invited to join European scheme for joint purchase of ventilators, and refuses. Boris Johnson lifts restrictions of those arriving from Coronavirus hot spots.

    March 14th Government is still allowing mass gatherings, as Stereophonics play to 5,000 people in Cardiff.

    March 16th Boris Johnson asks Britons not to go to pubs, but allows them to stay open. During a conference call, Johnson jokes that push to build new ventilators should be called ‘Operation Last Gasp’.

    March 19th Hospital patients with Coronavirus are returned to care homes in a bid to free up hospital space. What follows is a boom of virus cases in care homes.

    March 20th The Government states that PPE shortage crisis is “Completely resolved”. Less than two weeks later, the British Medical Association will report an acute shortage in PPE.

    March 23rd UK goes into lockdown.

    March 26th Boris Johnson is accused of putting ‘Brexit over Breathing’ by not joining EU ventilator scheme. The government then state they had not joined the scheme because they had ‘missed the email’.

    April 1st The Evening Standard publishes that just 0.17% of NHS staff have been tested for the virus.

    April 3rd The UK death toll overtakes China.

    April 5th 17.5 million antibody tests, ordered by the government and described by Boris Johnson as a ‘game changer’ are found to be a failure.

    April 7th Boris Johnson is moved to intensive care with Coronavirus.

    April 16th Flights bring 15,000 people a day into the UK - without virus testing.

    April 17th Health Secretary Matt Hancock says “I would love to be able to wave a magic wand and have PPE fall from the sky.” The UK has now missed four opportunities to join the EU’s PPE scheme.

    April 21st The Government fails to reach its target of face masks for the NHS, as it is revealed manufactures offers of help were met with silence. Instead millions of pieces of PPE are being shipped from the UK to Europe.

    April 23rd - 24th Government announces testing kits for 10 million key workers. Orders run out within minutes as only 5,000 are made available.

    April 25th UK death toll from Coronavirus overtakes that of The Blitz.

    April 30th Boris Johnson announces the UK has succeeded in avoiding a tragedy that had engulfed other parts of the world. At this point the UK has the 3rd highest death toll in the world.

    May 1st The Government announces it has reached its target of 100,000 tests - They haven’t conducted the tests, but posted the testing kits.

    May 5th The UK death toll becomes the highest in Europe.

    May 6th Boris Johnson announces the UK could start to lift lockdown restrictions by next week

    You missed the bit where it took until this week to come up with any sort of controls/ checks at the border.

     

    39 minutes ago, CharonY said:

    How US-centric can one get? Jeez. 

    About as US centric as the US.
    But, by thunder, you have to work at it.


  12. 10 hours ago, Airbrush said:

    he lighter droplets are deflected over the heads of people after the sneeze droplets travel about 10 - 15 feet. 

    By what?

    Also, many or most rooms are only about 10- 15 feet across.

    10 hours ago, Airbrush said:

    The droplets do NOT travel across the room, only about 15 feet.

    Again, that's a matter of wealth, not physics.

    10 hours ago, Airbrush said:

    Also, you can catch Covid-19 by droplets reaching your eyes!  So you need eye protection as well as an N95 mask.

    Yep.

    You will see people wearing it in clinical situations.


  13. You don't need to go to roswell, just a hardware store.

    Buy a hammer.

    Lift it up then drop it on a rock.

    Calculate the power input to the hammer, and the power output delivered to the rock.

    1 hour ago, NineTwentyEight said:

    You need to encase a circular array of polarized light filters in a donut shaped mirror and let one spot open for sunlight (a sorting demon like doorway) or your flashlight to get into it and see if you can't get more energy than you put in. 

     

    The first time around the energy put in will drop to 75% but adding another ray along side that 75% should give you 150% by letting the second ray in by opening the door and not letting out the first beam.

    You can't harness this vacuum energy unless apart of the donut is just magnifying glass. At thousands of percent energy input one could collide spiraling rays of gamma shifted photons, and then on top another quasi particle, and you get to push quarks out of the magnifying glass. It either creates beams of quasiparticles or the experiment is a failure. 

     

    If you draw a picture it will be more clear what you are wrong about.


  14. If people sneeze  at 100 miles per hour then, to make sure that the particles go up not across, you need an upward velocity near 100 MPH
    You need that all across the room- because you can't be sure where someone will be standing.
    Such rooms exist...
     

     


  15. On 5/13/2020 at 10:00 AM, Carl Fredrik Ahl said:

    Hi,

    I can't find much information about concentrated hydrochloric acid and the uses for it. I find much information about regular hydrochloric acid, for exemaple that it is used to regulare pH in stuff and are additives in food. Can you plz give me some examples of what concentrated hydrochloric acid is used for and how it differs from regular hydrochloric acid.

    If you buy commercial hydrochloric acid- unless you specify a different concentration- you will get concentrated hydrochloric acid.

    Other solutions are made by dilution of the acid.

    The name is not a description of the manufacturing process.

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