41

General Science / Re: How do we make synthetic gasoline?

« on: 26/05/2022 10:23:38 »

Yea, Stanley meyer was a notorious hoaxer and fraudster. He died from coronary atherosclerosis but the looney conspiracy theorists claim he was murdered by the fossil fuel industry-nonsense. A bit off topic but when the germans ran short of fuel in ww2 they came up with a process to directly hydrogenate coal to produce synthetic hydrocarbons. I don't think it worked very well.

Well Fischer Troph process produces a pretty large volume of fuel base stock, along with a lot of other plastics precursor chemicals. Exported all over the world as a technology, even to the Gulf states as a way to improve the natural gas they have even more of than oil, and which is mostly used to generate power in turbines, or simply burnt off as flare gas. Turn into a usable fuel, or a plastic base means it appreciates in value considerably, and as a bonus the fuel or feedstock is no longer as dangerous to transport as liquefied gas.

42

Physiology & Medicine / Re: What is the best blood pressure monitor for home use?

« on: 26/05/2022 10:17:33 »

Yes, I can always measure my BP as normal at the doctor's office, simply because I have sat and deliberately relaxed for at least a half hour before in the waiting room. When I go in with high BP, he has pretty much known I was really ill. But on mild control, because it can be higher then normal, but despite being the same age, height and weight as him my dose is very much lower. Being a doctor is stressful, my first doctor there nearly dropped dead from a full blown coronary at 28, despite him being ultra fit, a runner, cyclist and in perfect health. Only thing that saved his life was that this was at the office, with a full set of other doctors there, good nurses, and the full set of necessary equipment to restart him, keep him oxygenated and get him to a hospital and on a table within 45 minutes. Still a doctor, but cut back a lot on his patients, and only works near home now.

43

Cells, Microbes & Viruses / Re: Monkeypox: Could it be similar to cowpox, and just a mild variant of smallpox?

« on: 26/05/2022 10:04:51 »

Wonder how effective the smallpox vaccines are after a few decades of being used, as I had the pressure injection at primary school, many years ago.  But will say the Covid vaccines are pretty effective, still here, despite having had it likely at least twice, but both times a negative test result, which is still possible with the quick tests. Last one was just like a moderate case of flu, while those who are antivax seem to be selecting themselves for Darwin awards, with a very high probability of winning one.

44

Chemistry / Re: What colour is paint before the colour is added?

« on: 19/05/2022 06:45:22 »

Yes, white lead oxide as brightener in paints, and arsenicas Sceles green, a very popular colour for wallpaper in Victorian times, which also had the unfortunate problem of outgassing arsenic vapour, and the same arsenic compounds were used to dye clothing, along with their use, as arsenic oxides, mixed with lead oxide as face powders.

Then you have, even to this day, mercury compounds that you can still buy, used as skin lightening creams. Banned in most countries, but still made and brought in all over the world.

45

Chemistry / Re: What colour is paint before the colour is added?

« on: 18/05/2022 18:16:23 »

Your paint base can, for the vast majority of the colours you can buy in stores, be made from one of two formulations. Both are an identical blend of vinyl acetates, that are the binder, and all the other ingredients that get added to it to give weather resistance, water resistance, gelling ability and such, creating the base compound. Then they mix in filler materials, which are there to give bulk and provide the gap filling and levelling ability. For those intended to be tinted dark colours, the so called deep tint base, this is finely powdered chalk, added along with magnesium oxide powder, so as to allow a dark colour tint to predominate the finish colour.

For those that are destined for light bright tint there is a lot of titanium dioxide added, as a white reflective part, along with the other chalk and magnesium oxides, so that light is reflected off it well, giving you the base of white PVA paint, which is the base coat that your lighter colours are tinted with.

In the store, or at the factory, if they are making bulk batches of paint, or a single can in the store, you get a colour pack added to the base, and then mixed to disperse it through the bulk liquid. The colours are generally composed of large amounts of the colour pigments, organic molecules in the most part, finely ground, and mixed with the acetate base and stabiliser that is the base without the filler, and deeply concentrated to a consistent particle density, and then packaged in smaller paint tins, for retail mix typically 1l plastic tubs. Then at the store level you have your paint swatches, which are all coded as to the colour, and that colour number is used by the mixing computer (almost invariably computer controlled these days, rare to find a shop with a manual mixmaster and a recipe book telling you the info for each base, quantity and colours to add to get the desired colour) to drive an automated dispenser, which takes a carousel of the various colours, all regularly stirred so the pigments do not settle out. Then it rotates the carousel to the desired colour, and activates a precision pump that dispenses the volume of pigment needed per colour, from 0.1ml to 200ml which is dropped direct into the opened can underneath. After the dispensing the can is sealed again, and placed in a shaker to blend the individual colours into a single homogenous paint in the can, and also mix the settled pigments in the can as well.

Your colour will be made from up to 10 different volumes of pigment, often containing black, brown and green, even for the predominantly blue colours, just to shift the colour to the right shade to match the colour samples.The 20 odd mix colours are also added to the oil based paints, where the PVA base disperses in the oil base, and still provides a similar colour, though your colour there will have a different formulation, adjusted for the different base, to get a very close colour match irrespective of base component. There is slight variability between batches, which is why you get told by professional painters to order all the colour you need as a single batch, or at least paint a room with the same batch, so as to not have slight colour shifts in the pastel tints. And yes, one of the colour tints is actually near pure titanium dioxide, added to make the brighter shades of light pastel paints, adding extra reflection to the paint.

An anecdote is the one new complex decided on the colour they wanted to use outside, which resulted in them needing to use 1.2l of the phthalo blue tint per 25l bucket, so they actually got 26l per bucket of paint. They ordered so much that the paint mixer shop, who were supplying them with the paint on demand, was not using the 1l tubs of phthalo blue to mix, instead receiving it in 200l drums, and using a drum pump and a bucket, to move it to next to the mixmaster, and then pouring in 2l at a time, while the machine was dispensing. They never got the blue stains off that area of floor. I wanted a 5l paint mix, so simply grabbed one of the older staff who knew how to use the manual mixmaster and the recipe book, as I had already gotten the 5l can of deep tint base off the shelf, I knew the base needed. They had a pallet of 25l buckets ready to go out, and another under construction, with 10 stacked there for the rest of the week. They were getting 20 pallets a week of just the one base for this order, and it took 3 months to complete.

46

Chemistry / Re: Can we make a microwave that cools down food?

« on: 16/05/2022 08:05:24 »

You can do so, though this is normally limited to very small volumes, where you use laser light that is just short of the wavelength that will stimulate emission of a photon, so that the higher energy atoms will eventually emit a photon, and then lose energy. About the only way to cool matter down to millikelvins, you rely on quantum effects to remove energy from the tiny volume of material, stripping it off a photon at a time. You can also do it with microwaves, just the materials you can cool are more limited, though the volume can be larger. This all takes place in a very high vacuum, well insulated so that you do not get stray energy leaking in. Not going to cool your food down, but works for physics experiments with Bose Einstein condensates, where you have matter acting like a massive single quantum particle.

47

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

« on: 04/05/2022 08:11:05 »

Would have to be big, and to make a tsunami in deep water that shelves towards the UK mainland. North sea would be possible, would swamp parts a little of the north, but any one that is detonated would result in harm to many other coasts at the same time, leading to the USSR getting a few replies sent to them space express.

48

The Environment / Re: (What's) the optimal temperature for life?

« on: 01/05/2022 09:39:04 »

Problem with that is assuming the temperature is even, but you instead have a hot band around the equator, and a cold band around the poles. In the middle you have a termperate zone, and as temperatures increase this tends to migrate towards the poles, and retreat from the equatorial regions. Unfortunately most of the land mass is concentrated either at the equator, or in the current temperate zones, so this results in less land being available, plus a warming ocean disrupts the existing currents, that otherwise distribute heat around, so that the massive temperate land that is most of Eurasia would become either colder, or have worse weather.

The existing tropics would also tend to die out, which will cause massive disruption, as they are a major source of both oxygen, and also a large part of the biomass of the planet. Deserts both on land, and in the oceans, as the hot water there is less amicable for life, and thus will isolate the planet into 2 halves, with it being difficult to survive the crossing as a species, and also leading to the tropics becoming a massive desert region, devoid of most life.

49

Cells, Microbes & Viruses / Re: How can we test new vaccines quickly?

« on: 28/04/2022 12:18:40 »

Vaccines are given, just that many do not get any sort of booster shot, or even get the free 6 in one vaccine, or the immunity wears off with time. Big issue is the rise of MDR TB, which is starting to be the dominant strain, immune to the cheap drugs the state program gives, and needing higher doses, plus many patients do not complete the full 6 month treatment, stopping after a month or two, because"I feel well now" and thus also selecting for the drug resistance, and then also the double whammy of high HIV rates that make it the killer it is. Many thousands of silent carriers of it as well, and it is very much a common ailment, no respector of age, sex, living standard simply because it is so easy to spread. CV has also contributed to the spread, with the TB clinics and the testing programs having been curtailed or shut down because of lack of money or staff, so it is a growing problem, also being spread by being a tough disease, and able to survive on masks for a while, so enhancing the chance of being breathed in or getting onto mucosa.

50

Cells, Microbes & Viruses / Re: How can we test new vaccines quickly?

« on: 28/04/2022 08:29:33 »

TB is still alive and thriving in Africa and Asia though, very common, and often the major cause of death in HIV patients, as an opportunist infection.

51

Chemistry / Re: Why do my drains small like Sulfuric acid?

« on: 26/04/2022 19:29:09 »

Digestion of the organic molecules in the blockage releases sulphur compounds from the amino acids in the sludge, which thus smell like sulphuric acid, because the lighter ones, like SO2, will react with water in your nose to give the same result.

52

Technology / Re: Are solar panels worthwhile?

« on: 18/04/2022 13:26:45 »

True, but there are other places that are not UK weather wise, with rain most of the time (my current weather notwithstanding, there is a cyclone dumping over a half metre of water so far, which is leading to the area being declared a disaster zone, but normally you have at least 8 hours a day of full sun here) to drop output, so there are plenty of locations that offer better use of the panels.

53

Technology / Re: Are solar panels worthwhile?

« on: 18/04/2022 10:52:29 »

Depends on what you use to generate the power. Coal is cheap, and common in China, where 90% plus of all solar panels are made, though hydropower is also a good part of the energy mix there, so the energy mix is somewhat different. The advantage of solar is that they can last 25 years plus, and thus will recoup the energy in production, and are also recyclable with relatively little extra effort, as now you have the components easy to separate, if somewhat labour intensive, but still worth the energy 25 to 50 years down the line.

54

Geology, Palaeontology & Archaeology / Re: Did ancient builders suffer from respiratory disease?

« on: 11/04/2022 13:24:58 »

Yes many did, but, as they very rarely lived much past the age of 40 or so, and died from things like malnutrition, starvation, disease and war, the silicosis was not exactly going to be a worry for them, as the chances of other things getting in first were so much greater.

Just like modern life, where the majority cause of death now, at least in developed countries, tends to be things like cancer, heart attack and diabetes that cause the majority of non violent deaths. Even s recently as 150 years ago not many people made it past 60, but now there are many who are still healthy and working at 70 plus, and many more are living well past 80.

55

Chemistry / Re: Will a water and diesel mix decompose at 500 degrees Celsius?

« on: 07/04/2022 06:58:04 »

Water at 500C will be a supercritical liquid, with close to 1GPa pressure, and will be an incredibly good solvent as well. Same with the diesel fuel, though you probably will want to use RP1 kerosene, as it is a lot more stable at that temperature, as it has been refined to remove all the long and short carbon chains, leaving most of it as being roughly the same length organic molecules.  You mild steel will be reactive though, as most modern mild steel contains enough trace metals, like Vanadium, Chrome, silicon, manganese, molybdenum and nickel, all either contaminants in the original steel scrap it is melted from, or added to get the steel to a specific formula, as steel these days is a vastly different metal than steel from 1900, all the added components make it stronger, more resistant to deformation and more able to deform elastically.

Reason Musk uses stainless steel is simply because it is very much better, performance wise, in thin section, so he has to use less material to handle the pressure. That it also has a oxide layer on the surface that provides corrosion resistance is a bonus.

56

Chemistry / Re: What happens when you melt gold into glass?

« on: 05/04/2022 19:30:44 »

Gold does react chemically, just that normally it is hard to get it into the ionic state, so typically those kind of reactions start with dissolving the gold first in aqua regia, where the mix of nitric and hydrochloric acid enables the gold to dissolve into the nitric acid, and then stay as a relatively stable gold acid thanks to the hydrochloric acid. Just normally gold is very insoluble in anything other than strong acids, so mostly occurs as a metal or a very low concentration of ions.

57

Physics, Astronomy & Cosmology / Re: How does ice actually freeze?

« on: 02/04/2022 05:43:46 »

NO, bulk of the water is below the surface, and at 4C, because that is where the density of water is at it's highest. Then the upper layers cool down further, and as they cool down they float on the deeper cold layer, so only the top layer will eventually reach 0C, and being at the top, and lowest density, it will continue to lose heat by radiation, till eventually it has lost enough energy for the ice crystals to start to form, and grow to cover the top.

58

General Science / Re: Do air sealing machines really preserve our food?

« on: 31/03/2022 20:13:52 »

Vacuum sealing, and heat sterilisation, is very effective to prevent bacterial growth, and if you do not want to go to the heat sterilise method, then you can still vacuum seal and freeze, which will keep the food from bacterial contamination for many months, though the lower the temperature the better, which is why long term frozen storage is at -80C, as pretty much nothing grows at that temperature bacteria and mould wise. If you want even longer storage time then you go to liquid nitrogen temperatures, which is effectively going to last decades, though if you want the longest period you have to put it into a rocket and launch out on solar escape velocity, or at least enough velocity to get out to around the Oort cloud, where the temperature is only around 4K, and it will be there till the sun runs out of Helium and goes into it's red giant phase, when it might get up to 6K for a few million years.

59

Geek Speak / Re: How good are modern computers at decoding WWII communications

« on: 31/03/2022 16:44:25 »

Did not say it would be a few seconds, but the decoders and encoders will run on any modern smartphone that can run the apprpriate languages.

however this is a nice enough video by Brady about it.

60

Geek Speak / Re: How good are modern computers at decoding WWII communications

« on: 31/03/2022 06:20:49 »

Most of the decoding relied on the rigid message structure in the messages, as they all, like weather forecasts, either had a very well defined structure, with known words in them in known positions, or a very easy to guess preamble and postamble to all the messages, so that all your decoding had to do to brute force the approach was to run through, looking for this known set of characters in this known position, like a date, and then you would have a very much reduced set of combinations that would produce this.

Also assisted by the quirk of Enigma that an encrypted letter would never be the same letter coming out, which helped in eliminating a lot of the combinations off the bat, saving computation time. The breakthroughs came because the same message was sent two times in each case, using the same settings, because the far end operator ran it through as it was sent, and at the end the paper was printed with garbage, not the expected end of message, indicating an error. Thus the request to resend, and the sending operator did not follow protocol, and use the next setting number in the code book, a way so all messages were only sent once, and then the code was not used again, a one time pad that means the messages have to be decrypted individually. Instead sent using the same number, but crucially the beginning was the same, and only in the body of the message did the operator start to use abbreviations for words, so the message after encryption was somewhat shorter, but had the same information.

This allowed the brilliant decoders to decode this message, and also work out that the sequence numbers were a single digit change in the one wheel, which made it possible to start each day with the previous one's decoded results, and thus massively reduce the amount of decoding time.

Remember the Enigma machine went out with a code book, which gave, for each machine, a set of code wheel start positions for each day, a set of pegboard wire settings for the current code book, and then a set of start positions for each message, which was also logged with the message cleartext in a code log. For submarines this book would be for a 6 month period, though superceded with a new book every time they came into port after 3 to 5 months. For the rest there were monthly or weekly code books, and every so often the Command would be paranoid, and swap out all code books to new ones.

Modern computers can easily do the brute force decoding with the original messages, simply because they can run through the entire 7 digit code space in a few minutes, looking for those known sequences, and storing the settings that gave them. Then you got a smaller set of locks of letters and numbers that would be parsed as to then having the correct preamble, and that, in the blocks of characters that came out, you could have correct phrases and words in there, passing those ones to the operator to read.

Remember your smartphone is equivalent, in processing power, to all the computing power in the world in 1945, including all the university computers, and so much more faster as well by orders of magnitude. Thus unbreakable codes then are merely a few minutes of work, and those Enigma machines were all sold on by the UK government to other countries after the War as a secure "unbreakable" communication method, which was Ultra Secret in the UK that those messages could still be read, using those original 1940's era machines which went to the Intelligence services, and which were maintained till the 1970's, when the last countries stopped using them.