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That CAN'T be true! / Re: Does mobile phone tower radiation pose health problems?
« on: 05/08/2019 21:22:15 »
What would be the point of radiating downward?
The greater exposure to radiation comes from mobile handsets, not the repeater towers.
The greater exposure to radiation comes from mobile handsets, not the repeater towers.
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63
Geek Speak / Re: Is hard drive recovery possible on Windows 10?
« on: 08/04/2019 09:39:57 »I am recently facing random issues with the hard drive on my Windows 10 and I updated the system to fix the issue, but after it, all my data from the hard drive has been lost and I can't restore the data from the drive anymore. Can anyone tell me how hard drive recovery is possible on my Windows 10 system?The website you had in your profile claims to be a recovery program, so this is clearly a poor attempt to spam us.
We’ve changed your website to ours, and banned you - no recovery from either by the way.
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64
Radio Show & Podcast Feedback / Re: Feedback on "Are we ready for the next Chernobyl?"
« on: 18/09/2018 19:53:47 »My hypothesis is that, as the background radiation there is mostly alpha, it may be comparable with the UK childhood leukemia clusters reported in the 1980s which were uniquely associated with those sites handling bare plutoniumSpoiler alert; they weren't.
How many people have been killed or made seriously ill in the uranium/pitchblende mining industries around the world?Good question.
This report suggests that the excess risk from being a uranium miner (compared to a miner of a different mineral like coal) is about a factor of two.
https://www.cdc.gov/niosh/pgms/worknotify/uranium.html
However, because uranium carries a lot more energy than coal you don't need anything like as many miners for the same energy .
So the same amount of energy mined as coal would kill more people.
In short, using uranium saves miners' lives.
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65
Radio Show & Podcast Feedback / Re: Feedback on "Are we ready for the next Chernobyl?"
« on: 13/09/2018 08:59:25 »I think that we are not ready for this. And anyway, we can not be ready for this anyway. It should be prevented that this would never happen in the future and will do everything possible to protect our future generation from the tragedy.You appear to be using your posts to advertise your homework/essay writing business.
We’ve replaced your commercial link with our own so you won’t show on search engines.
Oh, and by the way, you are banned.
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66
Physiology & Medicine / Re: What is the best blood pressure monitor for home use?
« on: 19/05/2018 21:22:36 »QuoteI would never measure my blood pressure at home. It is not a controlled environment.This is really a very bad recommendation. Every expert on the subject nowadays agrees that home blood pressure monitoring is much better than office BPM.
I have heard a world leading expert on the subject (a university professor) say that office bpm is useless.
There are 2 well known reasons for this: white coat hypertension and masked hypertension.
Home bpm is preferable over office bpm for both diagnosis and follow-up.
But don't take my word for it: ncbi.nlm.nih.gov/pubmed/16139119QuoteOffice blood pressure measurement (OBPM) yields higher blood pressure values than HBPM. For systolic blood pressure, differences between OBPM and HBPM increase with age and the height of office pressure. Differences also tend to be greater in men than in women and greater in patients without than in those with antihypertensive treatment. Furthermore, HBPM can diagnose normotension with almost absolute certainty; it correlates better with target organ damage and cardiovascular mortality than OBPM, it enables prediction of sustained hypertension in patients with borderline hypertension, and it proves to be an appropriate tool for assessing drug efficacy.
I second this; white coat hypertension is real and can lead to profoundly misleading measurements of blood pressure. My blood pressure is borderline pathological when another healthcare professional takes it, but when I'm doing it myself at home, it's normal.
Differences like this can make the difference between ending up being medicated, or not.
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67
Physiology & Medicine / Re: What is the best blood pressure monitor for home use?
« on: 17/05/2018 22:33:54 »
I've got builders in at the moment; I need one that goes around my wallet...
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68
Just Chat! / Re: APOLOGIES FOR THE RECENT DISRUPTION
« on: 08/01/2018 13:46:51 »
Observant users will notice that I have also managed to fix another irritation of the other forum, which was that clicking "login" when within a page took you back to the homepage upon successful log-in. Now it returns you to the thread you were looking at (which is what it should have been doing originally...). I discovered why while battling the other issues and fixed that too!
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69
Just Chat! / Re: APOLOGIES FOR THE RECENT DISRUPTION
« on: 08/01/2018 13:45:14 »Going to get a job as a SMF installer and maintainer then Chris, I can see there is a market for it.
HaHa - feels like it.
And, btw, "Say Thanks!" was prioritised yesterday just for you, Sean, since you asked so nicely!
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70
Just Chat! / Re: APOLOGIES FOR THE RECENT DISRUPTION
« on: 07/01/2018 12:18:45 »
Dear all
okay, pretty much everything is now restored and / or upgraded to a much more stable architecture. This should all perform more reliably and more quickly than it has before, and be more secure too.
Obviously, there may be bugs or unexpected behaviours. If you spot anything, please tell me and I'll deal with them. Also, please do make suggestions for improvements or upgrades we can make to ensure that we keep developing this place to keep it relevant to your needs.
Once again, thank you for being patient.
Chris
okay, pretty much everything is now restored and / or upgraded to a much more stable architecture. This should all perform more reliably and more quickly than it has before, and be more secure too.
Obviously, there may be bugs or unexpected behaviours. If you spot anything, please tell me and I'll deal with them. Also, please do make suggestions for improvements or upgrades we can make to ensure that we keep developing this place to keep it relevant to your needs.
Once again, thank you for being patient.
Chris
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71
General Science / Re: Where did this monster Fatberg come from?
« on: 17/09/2017 10:32:47 »
Good point, although I'd expect that to happen by the time the victim gets home, or at least to a more remote geography, rather than in the kebab shop itself; although, based on what I've seen sold in some of these places, amidst conditions that would give a food hygiene inspector a heart attack as well as salmonella, anything is possible...
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General Science / Re: Where did this monster Fatberg come from?
« on: 14/09/2017 08:35:26 »
I showed this to my kids - they were horrified and intrigued in equal measure!
We actually made a programme about sewer fatbergs and an pumping engine in London designed to run off fuel made using oil recovered from sewer fat
PS - I hope you don't mind my moving this to the mainstream part of the forum - I think it's really interesting and people might like to debate about it!
We actually made a programme about sewer fatbergs and an pumping engine in London designed to run off fuel made using oil recovered from sewer fat
PS - I hope you don't mind my moving this to the mainstream part of the forum - I think it's really interesting and people might like to debate about it!
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73
General Science / Re: Why are builders using small bricks?
« on: 13/08/2017 16:19:40 »
For those with genuine curiosity, http://www.jaharrison.me.uk/Brickwork/Sizes.html is informative:
Domestic and high-street buldings are subject to local planning requirements which can specify the size, color and even the texture of facing bricks to preserve some kind of aesthetic appearance, but we use much larger blocks of lightweight concrete for the inner leaf nowadays, and the block size used for some industrial buildings is limited by the "two man lift" requirement. I use large, high density ilemnite two-man bricks for linear accelerator bunkers and suchlike, to save space and minimise the number of joints (which compromise radiation attenuation if you're not very careful). Bricklaying machines do exist and are OK for boundary walls or factory facings, but they aren't much use in a confined space.
Quote
Several things influenced the size of bricks. They mustn't be too big, or they will be too heavy and awkward to pick up with one hand, while applying mortar with a trowel held in the other. They mustn't be too small, or a wall will need more of them, and more mortar, and more time to lay it.
Wilkes GobsIn modern times most bricks in UK are made to a standard size of 65x102.5x215mm, and laid with nominal 10mm mortar joints, but in former times the size varied quite a lot.
Some early medieval bricks were as big as 13"x6"x2". Late 15th century bricks were mostly about 9½"x4½"x2". A charter in 1571 specified 9"x4½"x2¼", and in the 18th century, Parliament specified 8½"x4"x2½", which is equivalent to the modern metric brick of 215mm x 102.5mm x 65mm.
What upset the apple cart was a brick tax imposed by the government in 1784. The tax was paid per brick, so brick makers responded by making much larger bricks, which meant fewer were needed for a given size wall. An extreme case was Joseph Wilkes of Measham, who produced bricks double the normal size (110x110x235mm) known locally as 'Jumbies' or Wilkes's Gobbs'', see right. The government later set an upper limit of 150 cubic inches (10"x5"x3") for a 'brick, which was still much larger than bricks had been before the tax.
The tax was repealed in 1850, but by this time, many brick makers, especially in the Midlands and North, had moved from hand-made to machine-made bricks. Having invested heavily in machinery it wasn't easy for them to revert to the smaller sizes, which meant that big bricks persisted for a long time afterwards. As a result you are likely to find bigger bricks as you move farther north, in buildings built before the introduction of standard modern bricks.
Domestic and high-street buldings are subject to local planning requirements which can specify the size, color and even the texture of facing bricks to preserve some kind of aesthetic appearance, but we use much larger blocks of lightweight concrete for the inner leaf nowadays, and the block size used for some industrial buildings is limited by the "two man lift" requirement. I use large, high density ilemnite two-man bricks for linear accelerator bunkers and suchlike, to save space and minimise the number of joints (which compromise radiation attenuation if you're not very careful). Bricklaying machines do exist and are OK for boundary walls or factory facings, but they aren't much use in a confined space.
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74
General Science / Re: Why are builders using small bricks?
« on: 10/08/2017 00:10:37 »A school girl was killed in a school according to the news by a small brick wall just because a gust of wind blew it over.large bricks are robust and have a MORE INERTIA for side forces.for example if you have a chain link fence and try to spray paint it you will be disappointed because the density of it is low.
It sounds to me like either (1) the wall you speak of was not well-constructed to begin with or (2) the wall was old and damaged and should have been torn down and replaced before it fell. Mere "gusts of wind" don't take down well-built, undamaged brick walls.
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75
Technology / Re: Why Can I NOT use an energy saving bulb in a dimmer switch light fitting ?
« on: 07/08/2017 22:49:23 »
It's true that the resistance of the filament is a fairly non-linear function of temperature: the resistance increases as temperature increases to its operating temperature. The temperature range is pretty wide from room temperature (around 300K) to operating temperature around 3000K; the resistivity changes by a factor of 16 over this temperature range.
See: http://physics.usask.ca/~bzulkosk/Lab_Manuals/EP354/ep354_thermal-radiation-lab_Tungsten-Temp-Resistivity.pdf
But the pulses of electricity occur fairly close together in time (8-10ms, depending on country). As a teenager, I used a photocell to detect the change in light output from incandescent and fluorescent lamps due to mains frequency. But the variation in temperature and resistance of an incandescent lamp is not huge, once it reaches operating temperature.
The crucial effect in capacitance is that the current increases before the voltage increases (I leads V).
- It is the opposite for inductance: V leads I.
- Both are energy storage devices - they continue to deliver a current, even when the voltage has dropped to zero.
For an incandescent lamp, the pulse of voltage increases temperature, which decreases current a bit later (V leads I, like an inductor).
But when the pulse passes its peak, the current does not continue to increase while the voltage holds the same polarity, but starts to decrease with the voltage (unlike an inductor).
- When the voltage reaches zero, so does the current.
- This is the essential characteristic of a resistor, not an inductor or capacitor
It is true that every resistor has a tiny bit of capacitance and inductance. But we can say that the capacitance and inductance of a light bulb is pretty negligible compared to the 1kΩ resistance of a 60W/240V incandescent globe.
See: http://physics.usask.ca/~bzulkosk/Lab_Manuals/EP354/ep354_thermal-radiation-lab_Tungsten-Temp-Resistivity.pdf
But the pulses of electricity occur fairly close together in time (8-10ms, depending on country). As a teenager, I used a photocell to detect the change in light output from incandescent and fluorescent lamps due to mains frequency. But the variation in temperature and resistance of an incandescent lamp is not huge, once it reaches operating temperature.
The crucial effect in capacitance is that the current increases before the voltage increases (I leads V).
- It is the opposite for inductance: V leads I.
- Both are energy storage devices - they continue to deliver a current, even when the voltage has dropped to zero.
For an incandescent lamp, the pulse of voltage increases temperature, which decreases current a bit later (V leads I, like an inductor).
But when the pulse passes its peak, the current does not continue to increase while the voltage holds the same polarity, but starts to decrease with the voltage (unlike an inductor).
- When the voltage reaches zero, so does the current.
- This is the essential characteristic of a resistor, not an inductor or capacitor
It is true that every resistor has a tiny bit of capacitance and inductance. But we can say that the capacitance and inductance of a light bulb is pretty negligible compared to the 1kΩ resistance of a 60W/240V incandescent globe.
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76
General Science / Re: Is towing Antarctic icebergs to the Middle East a viable proposition?
« on: 02/08/2017 16:29:44 »
I can give you a quick and dirty analysis (long story short, shipping is likely an order of magnitude more energy intensive than desalination):
According to this website (found through a quick google search): http://www.worldshipping.org/industry-issues/environment/air-emissions/carbon-emissions
Shipping by sea produces about 10 grams of CO2 for each 1000 kg moved 1 km.
The southern end of the Middle East is about 12000 km from Antarctica, so moving a ton of iceberg would produce 120 kg of CO2.
According to this report ( http://pacinst.org/wp-content/uploads/2013/05/desal-energy-ghg-full-report.pdf ) desalination of seawater requires at 12000–17000 kWh per ton of freshwater produced. And according to this website (http://blueskymodel.org/kilowatt-hour) if that comes from burning coal (worst case), this would only produce 10.9–15.4 kg of CO2. And this power could come from renewable energy (solar in ME is cheap), with no net emissions.
This would suggest that towing icebergs for water is not economically or environmentally reasonable. However, there could also be other factors worth considering: do those icebergs otherwise pose a threat to shipping lanes? Would desalination at scale have a detrimental effect on local marine life? etc.
Also, this analysis doesn't consider the footprint associated with the equipment (desalination plant or barge etc.), which might change the conclusion, but I think that due to the enormous scale of water markets, that the cost per unit will dominate over the capex.
According to this website (found through a quick google search): http://www.worldshipping.org/industry-issues/environment/air-emissions/carbon-emissions
Shipping by sea produces about 10 grams of CO2 for each 1000 kg moved 1 km.
The southern end of the Middle East is about 12000 km from Antarctica, so moving a ton of iceberg would produce 120 kg of CO2.
According to this report ( http://pacinst.org/wp-content/uploads/2013/05/desal-energy-ghg-full-report.pdf ) desalination of seawater requires at 12000–17000 kWh per ton of freshwater produced. And according to this website (http://blueskymodel.org/kilowatt-hour) if that comes from burning coal (worst case), this would only produce 10.9–15.4 kg of CO2. And this power could come from renewable energy (solar in ME is cheap), with no net emissions.
This would suggest that towing icebergs for water is not economically or environmentally reasonable. However, there could also be other factors worth considering: do those icebergs otherwise pose a threat to shipping lanes? Would desalination at scale have a detrimental effect on local marine life? etc.
Also, this analysis doesn't consider the footprint associated with the equipment (desalination plant or barge etc.), which might change the conclusion, but I think that due to the enormous scale of water markets, that the cost per unit will dominate over the capex.
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77
Technology / Re: SpaceBalls: How does this Japanese camera drone work on the ISS?
« on: 18/07/2017 08:23:09 »
I moved this here from Just Chat! because I thought it was really interesting and deserved more prominence. I hope that's okay, RD?
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78
Chemistry / Re: What is your favourite element in the periodic table?
« on: 14/07/2017 00:04:52 »
I think my favorite is radium.
It has looks to die for...
And also because due to her work with radium, Marie Curie was the first woman to win a Nobel Prize in physics (1903) and the first scientist to win two Nobel Prizes (second in 1911)
It has looks to die for...
And also because due to her work with radium, Marie Curie was the first woman to win a Nobel Prize in physics (1903) and the first scientist to win two Nobel Prizes (second in 1911)
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79
Physiology & Medicine / Re: How long does it take to become sober, and can this be speeded up?
« on: 24/06/2017 10:26:57 »Quote from: Brittany
Is there anyway to sober up faster?Drink in moderation?
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80
General Science / Re: Why do some people go to the same place every day and do nothing for hours?
« on: 20/05/2017 10:52:45 »Whether it's Parliament, Congress or the Dail, the object is to give a semblance of democratic legitimacy to an elected dictatorship.
Unlike Stormont, where professional criminals divide the spoils; Strasbourg, where the members have no constitutional authority over an unelected dictatorship; or Holyrood where they debate the merits of independence of a country that is entirely dependent on subsidies.
This is definitely quote of the week!
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