Erina

Without the "e". As Silicon can be CNC drilled, it led me to wonder of it's interior applications in a water environment, with extremities of heat.

I just found out that Silicon is a kind of metal, which apparently has nothing to do with the periodic table, and everything to do with it not ending in a vowel. I was wondering, does Silicon have useful properties for use in kitchen interior ?

Just testing

I am looking for right-angled metal cubes, with one vacant face to allow for concentric nesting, their tight tolerances allowing them to slowly sink under the force of gravity. Although CNC milled options would achieve this, are there any cheaper manufacturing methods ?

Do you mean dB levels of resistance ? I understand that a Russian doll approach of "layering" can multiply the level of dB protection. You can see from my drawing above the idea of two identical oven trays, of which are completely sealed on five sides, can be tapped together with aluminium/copper tape at either open end, right around their perimeter. Surely, this would shield the internal items to at least 40-50dB ?

What about a metal paint pot ? Surely that would work ? I meant metal tape, sorry.

I am unsure what you mean ? You mean the length of the wave e.g. low frequency ? Surely, higher frequency waves would be more of an issue ? With electrical tape around the two openings, that would be a secure seal ?

As a Faraday cage does not need an air-gap, and is basically a metal box, what about two oven trays placed edge to edge, with electrical tape used to seal them together, surely that would be sufficient ? https://www.amazon.co.uk/Baking-Cookie-Stainless-Healthy-Dishwasher/dp/B09L6R1LRZ/ref=sr_1_50?crid=1TF3AHE9L064K&keywords=oven%2Btray&qid=1666812048&qu=eyJxc2MiOiI2Ljc3IiwicXNhIjoiNi4wMCIsInFzcCI6IjUuNzAifQ%3D%3D&sprefix=oven%2Btray%2Caps%2C262&sr=8-50&th=1

I found this demonstration, which doesn't seem to have an air-gap: Can I really just place a HDD inside a metal pot, with some tin foil, and that will protect it from an EMP ?

My understanding is that a Faraday cage need not be grounded ?

You're probably right. However, with a metallic cover, I am hoping to keep the HDD/SSD safe.

With the war on the continent hotting up I would like to know how to protect my computing equipment against an EMP attack. I would like to avoid the whole "you'd have more things to worry about" line, and just stick to the science please. Specifically, how do I test a system ? I was thinking about placing a cheap HDD in an EMP protective environment and then inside a microwave, as I do not have the necessary devices to test for signals. I read about bags, but unless ironed the zip lock seal is a weak point. It seems that metallic cloth gives favourable results, and it's very much more flexible and robust, compared to a polymer bag. Any advice please.

Back to the subject matter, presently it seem that there is a 1:4 ratio with aviation fuel like Kerosene, due to the energy per unit volume being so much lower with Hydrogen, even in its liquified form. So I take it that whatever will be needed will be at least a four fold increase on current numbers ?

Thank you for the clarification: "optimising, by reducing losses". Charging and discharging is something that I also didn't take into account. Charge in: efficiency = (output energy / input energy) * 100 e.g. 1/1.5 * 100% = 66,6% Charge release (out): (charge from discharging / charge consumed in charging) * 100 So basically how much a battery doesn't leak, versus how much Hydrogen is leaked from its stored state, that is the main difference ?

Well the problem is that such decisions are cost driven. You raise an interesting point about propulsion through burning hydrogen, or powering battery cells, the former is most likely, due to space constrains from I have read, along with reduced costs. I am still looking for something concrete, if not a cost, then at least what levels of production are necessary, or infrastructure needed. Your Bureau Veritas threw up an conundrum for me that I hope you can answer: "While hydrogen has a favorable specific energy (about 3x higher than that of fuel oil) its energy density is 4-8 times lower".. what does that mean exactly ?

What I was trying to do was to present some factual real-world numbers, so that I could confirm the amount of Hydrogen that would need to be produced, and perhaps attempt to compare the end cost to the user, which in turn would determine the feasibility of switching over. The amount of noxious gasses emitted from Heavy Fuel Oil is not disputed, but how much would it roughly cost to switch to Hydrogen ? Other port side machinery will obviously be powered by Hydrogen, as well as surrounding public transport links and accommodation, so it was not just for shipping, but my main focus was.

People come out with all kinds of numbers (efficiency rates), but I wanted to find the formula to actually calculate it. I have that now. However, some say that the numbers produced are too low. So my thoughts were that the formula would only yield a base number, of which could be negotiated upwards, otherwise how could folk claim 80% efficiency ?

I take it then that 0.04% is the correct level of CO2 in the atmosphere then ? At 0.04% CO2 of the atmosphere, how relevant to climate change is its IR absorption rate, how does that relationship have such an impact ?

Hi studiot, I think that I'll take you up on your offer. My position is that I need bullet-proof stats, and therefore I need to be able to reference them to primary sources. 1/ I can now be confident that Cambridge Handbook of Earth Science Data (c2009) places CO2 near the bottom of a list of commonly found gasses in the atmosphere, correct ? 2/ Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere - there was some argument on the thread that the decimal place should shift over, and so I need to confirm this. Also, what it means i.e. how significant this makes CO2 ? 3/ Meanwhile I read that: the atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago - again, is it true ? 4/ We went through the water vapour issue just previously, so I am happy with that (although, it could go either way, so I still cannot be sure), but outstanding were the percentages quoted: Water vapour contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26% - independent confirmation of this would be useful, but it seems to lean toward the equilibrium position issue that you spoke of. Many thanks.

Given that there is a general understanding that large surface vessels, like shipping containers, are likely to benefit from being converted to being Hydrogen powered, over other non-polluting technologies like batteries, what are the practicalities of this ? On average a shipping container, worth its salt, will look something like this: Length : 400m Beam : 60m Draught : 14m Gross Tonnage : 210~235 TEU : 20~24k The fuel that powers their diesel engines is either IFO180 / IFO380, of which is trading today (mid-2022) at $506/mt on the World Bunker Prices index (Rotterdam) I read online that a 10k TEU container ship running at 24 knots would burn over 350mt of fuel per day, which would cost: $117,100k (£96,448). Given that the port of London, one of the UK's busiest, processed some 5,961 shipping container vessels in the year of 2021 (or 16 per day, flat out), and each one costs around £96k to fill up from empty (and they can last around 40 days on a full tank, but admittedly it can take just over one calendar month to arrive from China), how much would it cost to fill it up with Hydrogen ? Back in March of 2021 BP’s North East coast operations predict that they can produce Hydrogen at the rate of 1GW by 2030, which would produce 260,000 metric tons annually (or 712tn daily). Given that it would take 350tn to fill just a 10k TEU ship (which is half of a container ship’s capacity, on average) that doesn’t leave much for any other ship, with an average of 16 container ships visiting London’s busiest port daily (5,961 annually) - admittedly, London is not in the North East ! Therefore, to service the busiest port in the UK (either London, or Grimsby & Immingham) it would take some 16GW of energy, just to cover the container vessels for that one day, given that they would be carrying around 20k TEU, if they were all empty. Is this right ?

I meant that the formula was the base number, and then tweaking the process of energy production would allow for greater efficiency, and that's why some quote 80%.

My understanding is that shipping container vessels burn the remnants of fuel nobody else wants to touch, which wafts onshore from miles out at port. Such vehicles, are therefore ripe for Hydrogen conversion, but need a lot of it i.e. nuclear generated, for cost purposes. Granted, they won't put out much water vapour, compared to the surrounding sea, but are numerous as the world heavily relies on these behemoths for the way the world works today. And as an island the UK, which imports around 90% of her goods via the sea, Britain is no exception, and not a special case for an island nation. Am I right in thinking that any water ejected from the ships funnels would literally be a drop in the ocean. That the vapour would not rival that of its natural surroundings, is not permanently cumulative as the weather naturally cycles such gases, and so as a source of pollution it really is nil ?

It was actually a scrape from the comment's section. I rarely read the Editorial. I thought that it would be a little bit much to digest, so to start with Carbon Dioxide, everybody's favourite: The most abundant greenhouse gases in Earth's atmosphere in decreasing order are water vapor, carbon dioxide, methane, nitrous oxide, ozone, Chlorofluorocarbons, Hydrofluorocarbons and Perfluorocarbons. You mention that the above is conducive with Cambridge Handbook of Earth Science Data (c2009). This data then places Carbon Dioxide at the bottom of the elements in the atmosphere ? The poster focused on this: The atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago. I found the following from the MetOffice, which put CO2 at around 400ppm: https://www.metoffice.gov.uk/research/approach/monitoring/atmospheric-trends/gases-and-trends/carbon-dioxide But where do I get hold of the primary source to confirm this ? The following could perhaps be confirmed by your Cambridge Handbook: Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere. Where it gets interesting is when touching on water vapour: Water vapour is the main greenhouse gas element, but it would be hard to live without clouds and rain. It contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26%. If switching to a Hydrogen based energy production, with water vapour being the ejected gas, then wouldn't it be worse than sticking with what we're using now ?

Heat being a factor, I read something on the Tesla Motor Club forum that by controlling this factor the 80% can be achieved: https://teslamotorsclub.com/tmc/threads/charging-efficiency.122072/ But in essence, battery efficiency is the base for calculations, and it's anything up from there ?

Apparently, for every unit of energy extracted from a battery, it must be charged with 1.5 units ? Thus, battery charging equates to around 75% efficiency ?