Jack Jones

1.2K posts

Jack Jones

Jack Jones

@OtherJackJones

Just another Jack Jones

Katılım Aralık 2019
211 Takip Edilen25 Takipçiler
Jack Jones
Jack Jones@OtherJackJones·
@yFactr @male_leo_xxvi That's it. I don't know any more about the chemistry than that. Chloride ions in the salt break it down and cause it to rust faster. Rust is a bigger molecule than iron, so it expands and causes the concrete to break away exposing more steel.
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Gamma Factor
Gamma Factor@yFactr·
@OtherJackJones @male_leo_xxvi When I looked into this it looked like the reason was that concrete's high pH causes the formation of a type of iron oxide that forms a hard coating instead of flaking. Is this right? Do you know what form that is? And what does the salt do?
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Jack Jones
Jack Jones@OtherJackJones·
@yFactr @male_leo_xxvi Concrete is actually designed to crack severely before failure, to give a visual clue something is going wrong.
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Jack Jones
Jack Jones@OtherJackJones·
@yFactr @male_leo_xxvi The vast majority of concrete will have cracks of 1 scale or another, but the concrete protects the steel from any oxygen that gets through those cracks. The problem in the image shared is that salt water will strip the protective coating the concrete provides.
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∇·(𝜌𝐮𝐮) 🇺🇸
∇·(𝜌𝐮𝐮) 🇺🇸@male_leo_xxvi·
Why can't we just coat the rebar. Zinc it or nitride it or dip it in epoxy or something. Surely there's a solution here. What about just a shitload of aluminum rebar. Is there a voltaic thing
Steve Mouzon@stevemouzon

Reinforced concrete is fragile because it is self-defeating: the host material (concrete) is a really heavy sponge, delivering water right to the reinforcing that supposedly makes it strong, but water rusts steel. This bridge endured for less than a decade.

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Jack Jones
Jack Jones@OtherJackJones·
@darrellprograms @male_leo_xxvi In the UK we've trialed it in road construction. Looks perfect. Easy to handle light weight meshes of it, and road salts won't be a risk.
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Jack Jones
Jack Jones@OtherJackJones·
@darrellprograms @male_leo_xxvi It looks like really promising, only area it's not so good is the elastic modulus is lower, and it's shear strength is much lower than it's tensile. Because of the elastic modulus, it's not ideal for water retaining structures where controling cracking is important.
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Jack Jones
Jack Jones@OtherJackJones·
@male_leo_xxvi Small cracks let water in, which can then freeze and lead to big cracks. So steel often is the best choice. Stainless will work just as well, but that's expensive. It will often be cheaper to use regular steel and just design the structure properly.
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Jack Jones
Jack Jones@OtherJackJones·
@male_leo_xxvi There are also steel alternatives. There's FRP reinforcement, and basalt fibre reinforcement is very promising. The problem is all alternatives have a lower elastic modulus than steel, so they need to stretch more to take the load that means more small cracks in the concrete.
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Jack Jones
Jack Jones@OtherJackJones·
@Alwaysaslave27 @Simmons__ But it's not a benefit for having a disability, it's a benefit for having universal credit. If that's a concern it should be linked to having pip. If you look at HMS Belfast for instance, their discount for disabled people is trivial.
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Jack Jones
Jack Jones@OtherJackJones·
@thinkdefence There are so few of these aircraft left, I worry if it's sensible to still be flying them now that they're 80+ years old. A spitfire crashed in 2024, a B17 and Kingcobra in 2022.
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Think Defence
Think Defence@thinkdefence·
Do you think this should come from the defence budget, do we really need to keep 80 odd year old aircraft flying? I would extend this question to other services heritage equipment
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Jack Jones
Jack Jones@OtherJackJones·
@AaronBergman18 Tube stations at Canary Wharf, London used that construction method, built considerably below water level in an area with very high land value.
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Aaron Bergman 🔍 ⏸️ (in that order)
Aaron Bergman 🔍 ⏸️ (in that order)@AaronBergman18·
Serious question for #YIMBYTwitter: where height restrictions per se are the issue, why haven’t developers started building vertically but *down*, underground? I mean windowless apartments don’t sound ideal, but probably less bad than unaffordability and homelessness
Aaron Bergman 🔍 ⏸️ (in that order) tweet media
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Jack Jones
Jack Jones@OtherJackJones·
@Anon76546854773 @71Tonka @blagden_david How would they achieve that? The missiles are deep underwater and and in a steel tube. No signal is reaching it, an antenna for VLF could not be concealed. Even once fired the missiles is probably hardened against electronic attack, so no radio waves reaching what's inside.
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Max Muster
Max Muster@MaximoMustero·
@OtherJackJones @worstall socket with more than 800 Watt output itself. Need to quickly register the system via an unbureaucratic online form (2-3 minutes work). Experience so far has been great with more than a million systems installed.
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Jack Jones
Jack Jones@OtherJackJones·
@LoftusSteve I'd be happy if the change was each house had to have a ready connection on the consumer unit for solar to be added, but including panels as well doesn't seem like a huge problem as when they wear out they'll be cheap to replace.
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Jack Jones
Jack Jones@OtherJackJones·
@LoftusSteve Solar is very cheap if the wiring is already in place. You can get a 800w inverter for £100, and panels are as cheap as £75 each. It's getting your roof sorted and having an electrician do the wiring that costs a fortune.
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Steve Loftus
Steve Loftus@LoftusSteve·
The government really haven't thought this through. This will have £10,000 to the cost of a house. That's £10k added to your mortgage. So you will end up paying around £20k (with interest) over 30 years for a heat pump that might last you 10 and solar that might last 20.
BBC Breakfast@BBCBreakfast

Developers will be required to install solar panels and heat pumps in all new homes in England as part of updated planning requirements published by the government. Energy minister Michael Shanks told #BBCBreakfast plug-in panels that homeowners can self-install on balconies will also be available in supermarkets in the coming months bbc.co.uk/news/articles/…

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Jack Jones
Jack Jones@OtherJackJones·
@worstall The government now probably sees that risk as worth the benefit, which I'd agree with. There are other risks to plug in solar, but the technology on the unit mitigates them so shouldn't be a big concern.
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Jack Jones
Jack Jones@OtherJackJones·
@worstall The outstanding issue is that your circuits are rated to 16A, and are protected by a circuit breaker that ensures you don't pull more than that through the circuit breaker. If you're adding an extra 2A after the circuit breaker with solar the circuit could now be at 18A.
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Jack Jones
Jack Jones@OtherJackJones·
@thinkdefence Tandem wing designs offer very good lift to drag efficiency. Less safe than conventional designs as the plane won't automatically level out, but that's less of a concern if it's a 1-way munition.
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Think Defence
Think Defence@thinkdefence·
What is the most radically efficient wing form?. How do you make a one way attack drone that absolutely maximises ease manufacturing in bulk, right down ro selection of fasteners
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Keşfet

@yFactr @male_leo_xxvi @darrellprograms @Alwaysaslave27 @Simmons__ @thinkdefence @AaronBergman18 @Anon76546854773