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Question of the Week / Re: QotW - 24.12.12 - Is there any way to harness nuclear energy other than steam?

« on: 06/12/2024 21:03:07 »

The one that has the longest life is to use beta emitters and a tiny capsule, isolated in a vacuum, that relies on the beta particles, which are electrons, to provide a very tiny current to power ultra low power equipment Think of things like low power clocks that run on nanowatts of power when the equipment is shut down, and also powering static memory that stores data and configuration. Expensive, only made by a few niche manufacturers, and with ITAR regulations associated with the export of them.

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

For more information.

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New Theories / Re: Do Black Holes turn into something like Quark Stars?

« on: 29/01/2024 18:16:57 »

When the density drops below the point that gravity escape velocity drops below C, the energy stored will likely start to radiate out from the zero dimension singularity. As it starts to exit, it becomes normal matter, at really high energy, and this essentially appears to the outside observer ( sufficiently far away for safety, probably around 20 light years away, behind a neutron star as radiation shield) as if there is a sudden burst of energy equal to the temperature of the original universe forming, and making all sorts of exotic matter as the energy converts to and from photons and matter. You probably will get kilotons of Oganesium being formed, simply from the inertia of the initial matter and the matter being ejected in the next Planck unit of time, and hitting the existing mass. This then will appear as a massive burst of radiation and very hard gamma rays, plus floods of neutrinos that suddenly can travel out of their prison, likely taking around 30% of the mass equivalent in energy with them. Going to be mighty unhealthy to be in the local vicinity, probably will sterilise all life within 1000 light years pretty effectively, and will be making all the heavy elements nearby, likely 20 light years, fission rapidly.  this is for something like a galactic centre mass object, smaller ones less damage, and if there are primordial black holes possible, you will find a lot of them created here, and be speeding out at close to the speed of light as well. imagine something the size of a proton in diameter, but with the mass of the sun, moving at 0.9C.

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Technology / Re: How much abuse can a domestic microwave oven tolerate?

« on: 29/01/2024 17:59:41 »

Most common thing is that the reflected energy in the cavity will, due to the turntable, eventually return energy back into the probe end of the magnetron, leading to a high voltage flashover between the metal cap on the end and the waveguide cavity. This results in a burst of ionised air, and a dead short at RF of the magnetron output, with a loud bang. This RF short, with the stored energy in the magnetron cavities, and the capacitor between cathode and anode (the main capacitor outside has little effect, RF wise it is at the end of a really long RF trap by the cathode) results in the internal copper strapping inside the magnetron being subjected to very high currents, as the circulating energy is rapidly dumped via the output short, and those straps overheat and burn open circuit. This then results in the magnetron no longer being able to reach full power, even though it does draw the same current in operation, but the damaged cavities, like a whistle that has had the casing broken, will no longer oscillate with the circular flow of electrons from the hot cathode to anode.

You open the magnetron, and you will, after you saw through the end seal by the RF side, that there will be melted copper rings that strap the cavities together, so all cavities contribute to the RF output, even though only one has the output coupling loop in it.

https://upload.wikimedia.org/wikipedia/commons/1/16/Magnetron2.jpg

https://upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Magnetron_section_transverse_to_axis.JPG/800px-Magnetron_section_transverse_to_axis.JPG

This shows the rings clearly, you will find them melted with the magnetrons that have had arcing over. the heavy copper strap that is leading up is the output loop, coupling off of the one cavity, and the rings around the cathode (silver in the middle) are the straps that connect the cavities, and also act to reduce harmonics as they strap alternate cavities together so that they will all resonate at the same 2.4GHz frequency.

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Geek Speak / Re: Can you copy paste windows 7 programs folder into windows 8.1 programs folder

« on: 20/11/2022 21:20:44 »

Things have changed a lot since then. I run a VM in full screen mode, or run as a VGA size window, along with running Dosbox as well with it running some older games. Yes you notice some slight degradation, but the loss is more than made up with not needing to get annoyed.

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Geek Speak / Re: Can you copy paste windows 7 programs folder into windows 8.1 programs folder

« on: 19/11/2022 15:54:46 »

A performance hit of perhaps 10% on current hardware, likely more than 10 times the minimum required to run the guest OS, is not going to have much impact on most users, and virtualisation is built into almost all current processors.

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General Science / Re: So how big a nuclear bomb would it take to cover the UK with a tsunami anyway

« on: 18/11/2022 12:39:32 »

Dorothy, USA did similar as well, though unintentionally when it irradiated a whole lot of the Marshall Islands as well during testing.  The USSR also was not exactly careful with handling waste, which is why there are so many former Soviet republics with massive areas that it is lethal to go, and also large areas where the life expectancy is severely limited due to all the dumped nuclear waste there. USA also dumped waste, but at least has done a fair amount of work in both remediating and removing the waste, putting it into long term storage areas that do not allow dust to be blown away. There are ex Soviet area lakes where you can get a lethal dose of radiation within 5 minutes of approaching them, even in full NBC suits, and there even is a lake that has the dubious distinction of being ice free in Siberian winter, from all the radioactive decay there, and where approaching within 100m of the edge is lethal.

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Geek Speak / Re: Can you copy paste windows 7 programs folder into windows 8.1 programs folder

« on: 10/11/2022 15:02:06 »

Simplest is to use virtualisation, and turn that Win7 into a virtual machine, and run it from there. Same for the Win8, you take the entire machine and virtualise it, either Virtualbox ( but then you deal with the Oracle Borg if used for business) or one of the alternatives. That solves a lot of the issues, you get a machine that is easy to back up, you just clone the VHD and back it up, and you also get isolation from the host to client, so an issue on the client does not damage the host. As a bonus you also are able to run a few copies at once, all separate, and on modern (post 2010 in most cases) processors you get minimal performance difference, but a more stable environment.

A lot of malware also checks to detect running in a VM, and stops execution, so not executing on the VM, a small bonus for when you get some malware.

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Physics, Astronomy & Cosmology / Re: What would the implications for relativity be if the Australian dipole is real?

« on: 10/11/2022 14:49:30 »

If true then it will mean that SR is, like Newtonian physics, just a subset of a larger and more complex set of equations, with the large equations simplifying to SR when one of the components of it is either very large or very small, and thus dropping almost entirely into measurement noise of the experiments used to determine them.

After all F=MA is correct with small masses and small accelerations, but has a component related to C when either mass or the acceleration becomes a significant portion of C.

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That CAN'T be true! / Re: Are home water filtration systems a waste of money?

« on: 28/09/2022 17:49:30 »

If you live in the UK or a good part of the EU with strict water quality controls, no need at all, though a whole house water filter, around 5 micron, is a good idea to remove any sediments that can be in the supply line, though if you are in a freezing area it must be in the basement or otherwise protected from freezing, and have a valve at entry and exit to allow changing of the filter at least annually.

If you are in the USA, depends on your local water source, and what they care about quality wise. Rest of the planet the same.

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Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 23/09/2022 06:47:37 »

By me the most common bird involved in bird strikes are vultures and seagulls.

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Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 22/09/2022 20:36:45 »

Just remember to defrost them first........

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Plant Sciences, Zoology & Evolution / Re: Could a chicken fly?

« on: 22/09/2022 09:23:05 »

Well, peafowl can also fly, albeit not well, but they definitely do so, and there are only a few truly flightless birds, mostly the larger ones that are in general pretty well able to defend themselves, by either running really fast, or having a lethal kick. Chickens are well able to fly, but not far, just like most birds, having a certain range of flight ability.

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That CAN'T be true! / Re: Are home water filtration systems a waste of money?

« on: 14/09/2022 13:07:14 »

The best water filter system is a 4 stage Reverse Osmosis with a pressuretrol reserve tank ( usually 5 gal ). This is piped (1/4″ tubing to a spigot you install in the soap dispenser hole in the backsplash to deliver > 95% pure drinking water. House pressure must be 40 psi or better for this system but if your supply is short there are small booster pumps available.

Well, at least no spam here yet. Yes the RO systems work, but I still have reasonable water out the tap direct, not the mix of water types that is the USA. That varies from good to Flint, and also so much is well water. But even the harder well water is still good. I see the best water is NYC, because the water board there owns the catchment areas, and has a lot of rather strict laws regarding what they allow as to pollution of it, and what they can do if you do pollute.

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Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightning extremely-extremely rare?

« on: 05/09/2022 20:22:14 »

Normally done to pack in a lot more sardines, as now you can share leg space between the 2 rows, and thus leave room for more cargo as well. On the Hercules you also had the rather interesting toilet, which was just basically a tube to the outside, where the pressurisation removed liquid faster than you could produce it. However on those I flew on we only had seating sideways, edge of cabin and central row, allowing the space to be used for cargo. My seat of choice was right by the wing root, behind the thin red line on the wall (turbine blade comes through here, as shown by a few Antonov crashes recently), so you were at the most stable point on the plane, and could do odd things in turbulence, like have a bottle of cooldrink with the bottle going wild, but the level of liquid staying still relative to the bottle side. Yes i did have a few of the clear plastic baggies with, just for the queasy souls near me, though the guys on the cargo at the rear were literally flying in the back.

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Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightning extremely-extremely rare?

« on: 04/09/2022 10:07:43 »

Salt is an issue as you get salt spray even far inland, especially in winter from road deicing, so you really want to wash it off regularly.  Deicing has a detergent and a gelling agent in it, to both have it adhere as a film, and to stay in a thin film for long enough for the ionic salts in it to depress the melting point of the ice far enough so it melts. That stuff is corrosive, so you really want it to only stay on for a while before it melts the ice and falls off, and then is scrubbed off in flight. Most in flight deice is done using either electric heat or hot air bled off the engines, or via rubber boots that swell to break the ice off. Spraying the deice fluid at high pressure both ensures loose ice will be popped off, and also you want to get the fluid under the ice, and use pressure to move it off. A trickle will not do, you need to have enough pressure to cause the skin to vibrate, breaking the bond between ice and metal. That is why deicing has to be careful around probes and static ports, so as to not fill them with the corrosive liquid.

Aluminium will, for almost every alloy, have a thin layer of oxide on it, to be shiny the oxide just has to be thin, so the important part of it is to not grow the oxide, so you want to keep it clean, and a thin organic wax coat, or a thin polymer clear coat, will do this easily, though salt will cause issues by either dissolving the oxide, or growing it thicker.

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Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightning extremely-extremely rare?

« on: 04/09/2022 08:01:35 »

No need to keep polishing, just have to do a weekly wash to keep salt accumulation from building up. They do however give the metal a clear coat protective finish, which bonds well to the thin surface oxide, keeping the surface shiny. You save weight, because you do not have multiple layers of heavy pigment, just a single coat to protect. Alternatively you use something akin to an automotive wash and wax liquid, that removes the dirt and salt build up, and leaves a thin film behind.

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Technology / Re: How are redacted documents produced?

« on: 01/09/2022 12:36:38 »

Stupid version is to use Adobe's full suite and overlay the redacted sections with black, and then export it without first flattening it, which would make the characters disappear into the black. If not flattenned, you can simply remove the mask layer, and get the text back, which is often the step forgotten by most people doing this.

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Chemistry / Re: What happened to the 30% Oxygen content atmosphere?

« on: 01/09/2022 12:33:55 »

Got used up, converted to carbonate rocks in the ground and oceans, converted into biomass and water.

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Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightning extremely-extremely rare?

« on: 30/08/2022 21:42:51 »

The biggest points of strike are engines, as there you have very hot air, with plenty of ionised atoms in it, to initiate a discharge.  Then the pointy bits, all of which sport static discharge points so as to protect the metal, and those are relatively easy to replace, and are part of your pre flight checklist for damage.

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Physics, Astronomy & Cosmology / Re: Why is aircraft destruction via lightening extremely-extremely rare?

« on: 28/08/2022 18:47:21 »

Aircraft designers also know the parts most likely to be struck are pointy parts, like the top of the tail, the wing tips, the trailing edges of the engines, the nose and the rear stabiliser. Thus those parts, even those that move, do have rather substantial metal parts at the tips, and also have ground bonding flexible straps to bond them to the outer metal skin, and also the designers add in discharge brushes, rods of bare carbon fibre that will reduce charge build up and dissipate it, and thus reduce potential difference between the ambient and the aircraft, so reducing the chance of it being the cause for a discharge. The wheels also have the discharge brushes, and thus will shed charge as they get close to the ground, so there is no charge as the aircraft lands. Plus the same heavy flexible bonding straps, to conduct across the bearings so they do not suffer erosion from arc discharge.

Composite has the metal mesh embedded in it, or a foil of metal to act like charge spreader, and the large area means the unit current per square is low, plus brief, so the metal does not heat up much moving the charge across it. You might suffer damage, but it will survive. Of course you also do not fly into active storm cells, more due to the sudden steep air flow gradients being able to exceed the stress allowed on the airframe, there have been a good number of airframes written off for surviving flight through a storm cell, and the airframe exceeding it's maximum load limits multiple times, and the resultant stress deforming parts, so that, after landing safely, the airframe has been written off, because the number of failed rivets is uneconomical to repair.