jabl

69 ms·

931.
by jabl 4y ago
There is G100UL which seems to be promising as a 1:1 replacement for the current 100LL. Though regulatory inertia seems to be delaying a large scale rollout: https://www.avweb.com/insider/faa-continues-to-stall-on-g100.
932.
by jabl 4y ago
Algae fuels have been researched at least since the 1970'ies. In principle they are very promising, but it seems it's almost impossible to make these theoretical yield predictions work out in practice.
933.
by jabl 4y ago
In terms of the length of the hydrocarbon chains, winter diesel has shorter chains than summer diesel (to reduce the gelling temperature), which moves it towards a kerosene-like composition. So in that way you could say it's a blend of
934.
by jabl 4y ago
It is possible, the search keywords are "synthetic fuels" or "e-fuels" ("electro-fuels). Currently it's a lot more expensive than fossil fuel, which is why it's mostly a research project and not a large-sc
935.
by jabl 4y ago
Pyroprocessing was AFAIU developed so it could be done completely hands off. But that produces metallic fuel which is poorly suited to water cooled reactors.
936.
by jabl 4y ago
AFAIU without fast reactors they can only recycle the fuel a couple times before the isotopic composition becomes too poor for use in thermal reactors.
937.
by jabl 4y ago
I thought Stephenson gauge was chosen because there were a lot more rail miles and rolling stock using that gauge than Brunel gauge. In the end, it seems it's good enough. Both high speed trains as well as the heaviest freight trains e
938.
by jabl 4y ago
The problem is that if you lower the pressure enough to move the boiling point to something suitable for AC or refrigeration, the density of the steam will be very low. So you'd need huge pipes to transfer that heat around.
939.
by jabl 4y ago
> I'm assuming natural gas power plants wouldn't be convertible Nah, gas turbines are relatively flexible wrt fuel. Might need different injector nozzles.
940.
by jabl 4y ago
AFAIU CO2 refrigeration system are making a comeback. In Europe it's apparently fairly popular for things like supermarket refrigeration, partially maybe due to ever tightening EU F-gas regulations making a big investment into flouroca
941.
by jabl 4y ago
Water is a very good heat transfer fluid, it has a huge specific heat capacity compared to many other fluids, it's cheap, abundant, non-toxic, non-flammable. The problem is that if you want to reduce the temperature below ambient you n
942.
by jabl 4y ago
In Europe, and I think in much of the rest of the world except the US, isopropane or butane is used in common household refrigerators. Recently EU regulations were changed to allow these to be used in small split AC's as well, provided
943.
by jabl 4y ago
> It's measured in eV as it's the most precise* measurement you can make. Er, no. Just no. eV is just a unit, that doesn't make it more or less precise. eV had its origins in early accelerator physics work where it was a c
944.
by jabl 4y ago
> That's the argument of biofuels as well, correct? In principle, yes. Though everybody except the agriculture lobby has realized that there isn't near enough arable land on the planet for replacing anything close to current fo
945.
by jabl 4y ago
For instance, there's something called the Nudged Elastic Band (NEB) method that can be bolted on to existing ab initio / quantum chemistry codes, that allows one to calculate energy barriers between different states. Then you can
946.
by jabl 4y ago
> The authors likely didn't analyze it. That's my reading of the paper, yes. > It gives a value in eV, that can be extrapolated outwards though I am not exactly sure how. It gives values in eV, yes, and 1 eV ~= 96 kJ/mo
947.
by jabl 4y ago
I think neither. You just pump the liquid around, heat gets transferred via convection, and eventually the liquid goes through a heat exchanger.
948.
As HPC Chip Sizes Grow, So Does the Need for 1kW+ Chip Cooling(anandtech.com)
2 points by jabl 4y ago|2 comments
949.
by jabl 4y ago
The EU already has a project to introduce a replacement for the screw couplings used in EU rail freight today, the Digital automatic coupling (DAC). The "digital" part AFAICT comes from the ability to also connect air (for pneumat
950.
by jabl 4y ago
It's still a single core CPU, though, whereas the Xtensa-based ESP32 has a dual core CPU. Not sure people are actually using that second core in practice though.. And yes, this is probably an excellent case where RISC-V can win; wouldn
951.
by jabl 4y ago
We (well, the IT group at a previous job) used kerberized NFS with Ubuntu (16.04 and 18.04 IIRC) and netapp filers, worked fine. > Side-note: I wouldn't be surprised if LDAP+NFS is still pretty common across universities, either as
952.
by jabl 4y ago
I think the current implementation comes reasonably close to the old "intr" behavior. AFAICT the problem with "intr" wasn't that the kernel parts were impossible to implement in the kernel, but rather an application
953.
by jabl 4y ago
I think RVC is more or less universal if we're talking higher end than really simple micro-controllers or university student projects.
954.
by jabl 4y ago
> What makes an architecture CISC is when the instructions start to do too many things at once. For instance, on x86 you can write something like ‘ADD [rax + 0x1234 + 8*rbx], rcx'. Amusingly, one of the common criticisms against RIS
955.
by jabl 4y ago
intr/nointr are no-ops in Linux. From the nfs(5) manpage ( https://www.man7.org/linux/man-pages/man5/nfs.5.html ): > intr / nointr This option is provided for backward compatibility
956.
by jabl 4y ago
For Linux there's the richacl's ( https://en.wikipedia.org/wiki/Richacls ) which was an attempt to add NFSv4/Windows style ACL's to the Linux VFS. It never went upstream though, AFAICT largely becaus
957.
by jabl 4y ago
In the current NFSv4 RFC ( https://datatracker.ietf.org/doc/html/rfc7530#section-5.9 ) it says: > To provide a greater degree of compatibility with NFSv3, which identified users and groups by 32-bit unsigned
958.
by jabl 4y ago
Not just you. Selfish ME ME ME is the current zeitgeist. Heavily sponsored by today's robber barons who are taking the obvious action to deflect attention from their corporate empires towards identity politics.
959.
by jabl 4y ago
No.
960.
by jabl 4y ago
Another non-phase change method is the reverse Brayton cycle. Kind of like running a gas turbine in reverse. I think it is somewhat widely used in cryocooling, and in jet airliner cabin AC, but it seems to not have caught on for domestic he

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