* Posts by Alan Brown

14367 posts • joined 8 Feb 2008

Chinese researchers make car glide 35mm above ground in maglev test

Alan Brown Silver badge

If you can't afford the maglev, then there's the Metro line

It's pretty good and it's MUCH faster than any taxi

Alan Brown Silver badge

Yes, but that started suffering hunting oscillation (coning) and effectively destroyed both the pantographs and overhead wires in the process of setting that record

The practical limit of 350km/h (China) is based on trackside noise. They've found that even with maglev it's simply TOO DAMNED LOUD if you go fast that close to the ground

The Japanese maglev experiment has the same problem. Putting it in a trench hasn't really helped

To go faster, the track will need to be enclosed and evacuated

Alan Brown Silver badge

Maglev uses very little energy on the hover - the Shanghai maglev only uses 15kW for that part

On the other hand it draws 8MW punching a train sized hole in the air at 263mph - and there were a LOT of noise complaints - so many that they had to dial the speed back and it only runs full tilt on the weekday afternoon runs from 2-4pm

There's a reason vactrains (hyperloop) keep getting attention. The engineering for a steel tube able to withstand 1atm is pretty easy/cheap and even if you only reduce to 100 pascals (not difficult with almost any pump) you'll drop the power requirement dramatically. A leak will act as a fairly dramatic airbrake without pancaking the passengers

SiFive RISC-V CPU cores to power NASA's next spaceflight computer

Alan Brown Silver badge

Re: Size matters

"A deep space payload is going to encounter something hard and fast enough, eventually, that'll overcome any amount of shielding."

Once you're building IN space, using water(ice) bags will make life a lot easier. All those lovely hydrogen atoms bunched up nice and tight work pretty well at slowing things down

Using voting arrays of systems is a oretty good way of ensuring that any given particle hit won't be a major issue and once we're out at mars or further we're going to have to be looking at something better than solar power unless you want to see silly-size arrays (with attendant inertia and twisting moment problems)

Alan Brown Silver badge

Re: The wait is over.

Huawei has its issues (but at least not hardcoded backdoors like Cisco)

Hikvision's stuff IS a security issue (The monolithic SOFIA binary) - and that bleeds over into most of the other brands and no-name too (_all_ the SOC DVRs and network cameras are essentially identical under the surface)

Elon Musk claims SpaceX was in talks with Apple on iPhone 14 satellite services

Alan Brown Silver badge

Re: Only marginally useful

These things go well beyond SAR beacons. There are vast swathes of the planet without phone coverage (eg: most of the oceans) where the incumbents charge an arm and a leg.

Iridium is OK but limited

The whole communications paradigm is changing in ways that people are only just begnning to suspect

Back in the 1980s when I was installing AMPS stations nobody dreamed that everybody and his cat would have a mobile phone in their back pocket within 15 years, let alone a full fledged video-calling computer and global libraries of cat videos within 25 years - that stuff was Star Trek dreams of 2 centuries away, vs the certainty of flying cars being just around the corner

Apple warned by US lawmakers over using Chinese YMTC chips in new iPhone

Alan Brown Silver badge

Re: Apple needs to bolt from the US

"Do you REALLY want to hand over the key/core supply chains to THEM ?"

"Them" being who, exactly?

The USA has repeatedly demonstrated they're perfectly capable of shitting all over their allies for fun and profit and will happily go into full protectionist mode whilst simultaneously screaming "free trade"

The US version of "free trade" is much like the pilgrims "freedom of religion" - demanding freedom to oppress everyone who doesn't follow their beliefs. An actual free and fair playing field is an alien concept to them

Alan Brown Silver badge

Re: (DR-State)

" why is it important for US politicians"

Because American politics has descended into rampant tribalism and is pulling that country apart

Alan Brown Silver badge

Re: Another pathetic soundbite attempt

There is absolutely no reason for American tech companies to go out of their way to buy American made goods either.

Demanding loyalty never ends well and the increasingly shrill nationalist agendas coming out of various quarters has very uncomfortable echos of the leadins to both WW1 and WW2

Do we really want to go through THAT again?

Chemical plant taken offline by the best one of all: C8H10N4O2

Alan Brown Silver badge

Re: Coffee as glue

For future reference: adding water and leaving it 15 minutes usually allows things to unstick again

Alan Brown Silver badge

Re: Coffee...

Even coffee is corrosive when it has sugar in it. Seeing copper tracks eaten away was a routine thing if people didn't bring spillage devices in quickly (in the days before conformal coating was routinely applied to everything)

Alan Brown Silver badge

Re: Better yet...

Getting them to stand the laptop on the front edge on an absorbant surface (towel) seems to help (less stuff for the liquids to damage along this edge)

Alan Brown Silver badge

Re: Better yet...

"warm soapy water"

Too 'warm', obviously

On a serious note: A couple of steradent tablets in barely warm water (or a scoop of any oxygen bleach - it's the same thing in tablet form) works wonders on grotty keys (put them all loosely in a sealed container and shake well) and rinsing afterwards in ~75% isopropyl is the best drying agent as well as being a good biocide (95% is less effective as well as potentially damaging the plastic)

Alan Brown Silver badge

Re: Better yet...

Printing calculators in the pre- desktop-peecee days. It was worse if they had lots of sugar

(It was so common we had a procedure for it - which involved a bucket and hot soapy water)

Rest in peace, Queen Elizabeth II – Britain's first high-tech monarch

Alan Brown Silver badge

Re: Titles not necessarily constant

"Is Catalonia a country? Are the catalans a nation?"

Historically "yes" (it was a Principality as recently as the 1600s) - but European national (kingdom, principality, city-state) boundaries have been very fluid over time and there used to be a LOT more of them

Remember, Germany and Italy as we know them today didn't exist until less than 200 years ago, with France only being a fraction older

A country and an administrative region used to be defined by how far a man could ride on a horse in a day, or an army could march in half a day. Times have changed

Alan Brown Silver badge

Re: Liz Truss's hypocrisy

The same Liz Truss who previously tweeted effusive praise about one James Wilson Vincent Savile

https://twitter.com/trussliz/status/130291010730340352?lang=en

Alan Brown Silver badge

Re: This is a time of national morning, give it a rest for at least 10 days.

Migrant bears and marmalade sandwiches featuring heavily on the invites?

Alan Brown Silver badge

HM had a particular fondness for series 2&3 landies

Me, not so much (they were spectacularly unreliable compared to their japanese brethren)

Alan Brown Silver badge

The thing about a MOT is that it's only a certification that the vehicle was safe/emissions compliant AT THE TIME OF INSPECTION and is not a guarantee it is safe to drive _now_

That's why the fine print is there. It may also be evidence that the vehicle has been tampered with, if 3 days after passing the test, it's stopped with no cat and 4 bald tyres (which has happened)

Alan Brown Silver badge

Re: Anonymous because "They" are watching...

"Canada remains a monarchy mostly out of expediency."

As do most of the other countries who retain a monarch

There are a few countries on that list who are looking at swiching away from the figurehead. I suspect they'll find it costs a lot more than they were expecting (both financially and in terms of political stability)

Alan Brown Silver badge

Re: She was a good one

or (borrowing from Alan Moore): High Chancellor Johnson

Alan Brown Silver badge

Re: ta ta Liz

You've put your finger on the problem right away

"Figurehead presidents" are just that.

Problems tend to occur in countries where the president isn't a figurehead or has migrated over time from being one to being politically/administratively active

Alan Brown Silver badge

Re: ta ta Liz

The objection to killing varmits isn't that it's being done, it's the manner of doing so

Alan Brown Silver badge

Re: ta ta Liz

Given Truss' track record, I wouldn't.

Alan Brown Silver badge

Re: Out of sync there were loads of ghost images -> system overload….

"Gearbox overheating is the reason why the Osprey cannot stay in prolonged hover."

Or prolonged flight, in the case of 3 units in Norway. One is currently bogged up to the landing gear doors in a wildlife refuge having emergency landed on "rather soft" ground

Unhappy about excluding nation-state attacks from cyberinsurance? Get ready to pay

Alan Brown Silver badge

Re: Excluding them makes it worthless

" the only cyber attacks that have ever been acts of war are the ones perpetrated by Russia upon Ukraine."

Russia's cyber attacks on satellite terminals knocked out supervisory and safety systems at almost all windfarms in Europe

The TARGET might have been Ukraine, but the splash damage was widespread

And yes the industry is hellaciously sloppy. Not only on security

NASA scrubs Artemis mission yet again because SLS just can't handle the pressure

Alan Brown Silver badge

Re: hard choices

"repeat Artemis 1 in 2024 or maintain the schedule by putting a crew on Artemis 2"

If SpaceX's Starship is flying by then, what makes you thik that Artemis/SLS will still be a program?

At some point the sunk cost fallacy falls apart and things get scrapped

Alan Brown Silver badge

Re: Propellant from the moon

"Spin launch from the Moon has fewer technical difficulties than spin launch from Earth"

No (practical) atmosphere on the moon means that a railgun type launcher can be built at ground level and be far friendlier to biological payloads

Alan Brown Silver badge

Re: Third time's a .... ?

"If something catastrophic goes ping on the Moon"

Then the odds are pretty good that you're stuck there using whatever you have onhand

The lifeboat theory mostly falls apart when you look more closely at it. If you retain the resources to use it, then you don't need it

Alan Brown Silver badge

Re: Third time's a .... ?

Moon has a number of downsides including the abrasive dust issue.

It's been argued for a long time that if we can't go to Mars direct then we should target mining asteroids as this would be _easier_ (and far less dangerous) than the Moon (in fact the argument is that Asteroids should be first, planets later)

Ceres is one big iceball containing more water than the entire Earth's surface (oceans, rivers and atmosphere), others appear to have significant quantities of iron and other metals (virtually all metals mined at the earth's surface were delivered by asteroid strikes)

Alan Brown Silver badge

Re: Third time's a .... ?

Quick and Easy for whom?

I'm minded of a bunch of frankenstein projects I had to deal with where blowhard techs would exclaim "It's all proven stuff", then tie things al together using a rat's nest of other shit which wasn't tested properly and interfered with all the existing equipment, vs a simple redesign of the existing stuff to rescale it slightly ("Too hard, I forbid you to work on it")

Unfortunately such people end up in manglement and sales

Alan Brown Silver badge

Re: Hydrogen is HUGE

FOOF - safety equipment being a good pair of running shoes

Alan Brown Silver badge

Re: Hydrogen is HUGE

One of the reasons for using methane is that the tanks end up about roughly equal size. mass and temperature whilst still having a decent ISP and total thrust.

The temperature part matters more than you might think. Significant problems have been caused by tank/plumbing interactions between LOX/RP-1 and LOX/LH2 at various points in the past

Obtrivia: there are significantly more hydrogen atoms in a gallon of RP-1 (or any other liquid hydrocarbon fuel at room temperature) than a gallon of liquid hydrogen

Germany orders Sept 1 shutdown of digital ad displays to save gas

Alan Brown Silver badge

Re: FRA airport is very nearly in compliance with this law....

You don't need to go back to the 50s. I can recall that in the 80s along with ice on the INSIDE of the windows

Alan Brown Silver badge

Re: FRA airport is very nearly in compliance with this law....

Advertising displays mostly draw power in the backlight. If done correctly they should be down under a couple of watts when blank

Alan Brown Silver badge

Re: FRA airport is very nearly in compliance with this law....

"FRA was Germany's most important international freight hub"

One airport in New Zealand which had plans on ensuring its freight ops didn't get interfered with spent 25 years acquiring farmland under the approach paths to prevent development occurring and hoovered up all the nearby housing as it went up for sale - reselling it as leasehold with a covenant prohibiting complaining about the airport

It's one of the few without a night curfew. I wonder why? :)

Alan Brown Silver badge

Re: Exceptions for such dual-purpose signs have been arranged.

LED streetlighting can be dimmed 90% (or turned off entirely) and only brightened when there's movement below the units

Try doing that with a sodium or mercury fitting

Apart from the power savings, you get a large effect on light pollution

NASA scrubs Artemis SLS Moon rocket launch

Alan Brown Silver badge

Re: "Except for the higher pressure, hydrogen is no different than gasoline. "

"Adding carbon to hydrogen kind of defeats the whole point of using hydrogen in the first place - reducing CO₂ emissions."

That depends on the source of the carbon. Fossil fuels or old-growth forests are definitely out

Atmospheric carbon is perfect and a net-zero emitter as long as your energy and hydrogen source is zero-carbon (realistically this means nuclear power, not wind or solar - these processes need consistent energy sources)

Alan Brown Silver badge

Re: "Except for the higher pressure, hydrogen is no different than gasoline. "

"It takes about 3x the energy to compress or cool it as it does to mfg it."

This is why I tell people that if they have the abundant cheap energy available to manufacture hydrogen they may as well take the extra step of tacking on atmospheric carbon atoms to make it easier to handle at the next few stages (storage, transportation, usage)

Unfortunately talking to hydrogen proponents is mostly like dealing with Brexit cultists. They invariably invoke magic unicorn poo in order to get to step 1 (in this case, cheap carbon-free hydrogen - there's no point in stripping carbon off hydrocarbons to manufacture it - so no matter which way they cut it, the per kWh(*) cost of the hydrogen will be substantially higher than the per kWh cost of equivalent electricity, so the entire premise of reticulated domestic hydrogen gas networks or gas-fuelled cars falls apart and the only viable use case for synthetic hydrocarbon fuels is long-haul aviation or other niche purposes)

(*) or per 3.6MJ if you prefer

Alan Brown Silver badge

Re: One of the things not tested

That was true IN SPACE and amounted to 2-4psi

However that wasn't true on the ground and that's the root cause of the Apollo 1 fire

The problem was that they were pressurised to 2-4psi over atmospheric pressure _with pure oxygen_ in order to verify the leak integrity of the capsule (16.7psi, according to the report, vs 14.7psi atmospheric)

Pure oxygen at 16-18psi makes velcro (nylon) essentially an explosive and there was a LOT of velcro in the cabin - apparently various engineers had been pleading for these tests not to be done in case there was a spark, or at least to reduce the amount of flammables in the cabin, whilst the astronauts themselves were worried about the quality of the wiring

It turned out that the netting used for the wiring harnesses was also made of nylon

Once the fire took hold and spread from the wiring harnesses to the cabin velcro, pressure inside the capsule ballooned due to combusion gasses plus temperature rise and the door essentially corked itself shut. Bolted or not, it wasn't openable without several tons of force - an opening force that the ground crew weren't able to provide

https://aapt.scitation.org/doi/10.1119/1.5095379 - "The Apollo 1 Fire: A Case Study in the Flammability of Fabrics"

https://arstechnica.com/science/2017/01/the-hell-of-apollo-1-pure-oxygen-a-single-spark-and-death-in-17-seconds/

Alan Brown Silver badge

Re: One of the things not tested

"I am very conflicted about the usefulness of SLS"

Sunk cost fallacy - having spent that much on it, it's regarded as too expensive to scrap now

Alan Brown Silver badge

Re: Its a prototype

"SpaceX has singed the grass a few times it's self"

Yes, but they've always made it clear they expect to do so - and more importantly they don't have a bunch of cretins calling the RUDs "failures" or "boondoggles" and trying to slash funding

Alan Brown Silver badge

Re: Its a prototype

IIRC Columbia was "yet another rocket launch (yawn)"

We all know how that ended up

I realise you said "expectations need to be managed", but the political reality in an animal like NASA is politics, pork and inflated national egos

Alan Brown Silver badge

Re: 200% trust in NASA

"The fun thing is all of the upper stages are still untried at this point"

However there's only one SLS and the odds of a second one are slim to negligable

Alan Brown Silver badge

Re: 200% trust in NASA

That was a different "once"

Alan Brown Silver badge

Re: Fun with Children

I'm old enough and have lived in places backwater enough to have used phones with crank handles and needing to decode morse code rings to decide whether to answer the call

I also participated in replacing all those lines with individual service DTMF service a few years later as a young telco tech

My suspicion is that children would find the older voice-operated tech easier to interface with than rotary dials

Alan Brown Silver badge

Re: At this point

There's a bigger problem with going to the moon than the rocketry

The dust

Lunar dust _wrecked_ every apollo EVA suit in less than 30 hours. It's extremely abrasive and sticks worse than shit to a blanket thanks to electrostatic charges.

Once inside a pressurised environment it presents a major silicosis hazard due to its extreme fineness

Compared to mars it's an incredibly hostile environment and major efforts will be required to keep people healthy over and above anything already being done in space/zero-g environments

https://www.youtube.com/watch?v=EFqpgmZAZgo

https://www.youtube.com/watch?v=0k9wIsKKgqo

Alan Brown Silver badge

Re: 200% trust in congress

"Super Heavy and Starship remain untested and unproven vehicles"

They've gone from concept to prototypes in a startlingly short period of time and NASA wouldn't DARE repeatedly building up/tearing down prelaunch iterations until they felt happy about launching one. There's just too much political pressure on them for that option

Braking news: Cops slammed for spamming Waze to slow drivers down

Alan Brown Silver badge

Re: feels valid to me

" It was not just "not visible" but actually glowed grey."

This sounds like an "active interference" IR backlit plate - I'd still give the fottage to police as they tend to have multiple ways of identifying vehicles/drivers even with fake plates - if they're determined enough

Alan Brown Silver badge

Re: feels valid to me

"They're not even trying to position it as an legally defensible "anti-dust" cover or somesuch."

As with removing cats, selling the items or fitting them to the car isn't illegal in the UK. It's only when on the road that it becomes an offence

The workaround for that would be charges along the lines of "engaging in a conspiracy to commit criminal activity", but I'm betting that CPS would find that too hard to make stick even if they had video confessions from the sellers of the true intent of the devices

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