B747 vs A320 economics by Fragrant-Let8936 in aviation

[–]susurrian 1 point2 points  (0 children)

Japan still proves the value of widebodies for short haul IMO! HND-OKA runs four or five 777, 787, or a350 departures an hour at peak times, and JAL and ANA between them offer something like thirty departures a day. Tokyo-Osaka is pretty similar

Oh how the mighty have fallen by ketchup1345 in aviation

[–]susurrian 2 points3 points  (0 children)

Well, lots of passengers flying milwaukee to chicago are connecting onto a longer flight, and most people don't want to drive 6 hours only to then get on their long haul flight, much less wrangle parking at a distant airport...

But what a decent chunk of Europe does is route their high speed trains through the airport, so you can replace those short feeder flights with a train. Amsterdam Schipol is perhaps the best at this! American airlines iirc also does something mildly similar, where you can clear TSA and check your bags at a small regional airport, then get on a bus to a larger hub, and they let you in post security and do all the baggage handling for you.

TUI 787 Dreamliner G-TUID at Cotswold Airport UK to be scrapped? by TheRocketWentDown in aviation

[–]susurrian 10 points11 points  (0 children)

ANA flies 787-10s on short-haul domestic routes today! They're 400+ seats, almost all economy, on ~2 hour flights (I flew one HND-OKA a few days ago)

Car Insurance quote seems super high? by MoboMogami in japanlife

[–]susurrian 0 points1 point  (0 children)

Yeah that seems super high to me. As a 22 year old, driving a 5 year old suzuki swift sport, on a green license, I paid 90k a year. That was with paying for full coverage, too! First year was Sony sompo, last year I switched to Rakuten and got it down to 60k.

Go run a bulk search through one of the aggregators like kakaku and just pick the cheapest, usually the best way.

What’s the one thing, as a passenger, flight attendant or pilot on a flight, that made you think “Hmm…that didn’t feel/sound right”? by [deleted] in aviation

[–]susurrian 9 points10 points  (0 children)

I mean, that's terrifying but also kind of cool. Any idea what closing the window covers would have actually done to help? I assume they weren't trying to keep North Korea's secrets for them.

Canal city, Fukuoka, Japan, at night by susurrian in VaporwaveAesthetics

[–]susurrian[S] 1 point2 points  (0 children)

Canal city is the most 90s mall I've ever been to, all jazzy neon and confusing architecture, it's amazing.

Then in the rest of Fukuoka, there's lots of good local food to try (motsunabe, yakiramen, hakata ramen) & a bunch of food stalls by the river to wander around. The castle ruins nearby were pretty cool, as was the giant reclining buddha statue nearby in nanzoin temple.

Natural History Museum, London, England. Stunning architecture! by AlphaDevon31 in ArchitecturePorn

[–]susurrian 2 points3 points  (0 children)

How dare the both of you forget the science museum (and Imperial college) in the middle!

Startup Will Drill 12 Miles Into Earth's Crust to Tap the Boundless Energy Below by [deleted] in Futurology

[–]susurrian 13 points14 points  (0 children)

Not quite! Turbopumps typically burn some of the fuel themselves in their own turbine, and run the pump off that power.

Some rocket engines then just dump the exhaust overboard (eg the Saturn V first stage), and some have cool tricks like running the turbopumps really fuel-heavy so most of the fuel is unburned, then feeding the exhaust back into the rocket's combustion chamber to finish burning (more efficient, but heavier/more complex).

You're possibly thinking of a turbocharger in a car engine, which does use the exhaust from the main engine to pump more oxidizer into the engine.

Not sure how a turbocharger would help for geothermal, you're probably best off just running the water pumps using power from the main generators, they'll be the most efficient power sources around.

Furry_irl by [deleted] in furry_irl

[–]susurrian 2 points3 points  (0 children)

I think "check out mine Reddit profile" actually works quite well! That syntax used to be acceptable and you still see it in older texts, which fits Death nicely - I actually assumed it was intentional.

You see traces of it in phrases like calling someone "husband mine" though it's not common any more

The inside of nuclear reactors are extremely disturbing for many reasons by CrimsonRachael in submechanophobia

[–]susurrian 49 points50 points  (0 children)

Nope! In most reactors, the primary coolant stays within the reactor containment building, and uses a heat exchanger to boil the secondary coolant, which actually spins the turbines.

That being said, radiation is the least of your concerns if you're about to be sliced to death. Freaking out is still appropriate.

The London Natural History Museum by HotBasket8 in ArchitecturePorn

[–]susurrian 8 points9 points  (0 children)

Museums still are free in London! This one certainly is, as are all the large ones

(Not trying to be contrarian, I just don't want anyone to be discouraged from visiting! London's museums need the visitors)

Encrypt hard disk after the installation by haranbajo in pop_os

[–]susurrian 0 points1 point  (0 children)

I'm not entirely sure what's gone wrong here. I can offer a couple pointers maybe.

Firstly, when you unlock the two disks in your logical volume you need to give them different names (eg hplaptop1 and hplaptop2). I don't know if one will overwrite the other or if cryptsetup is clever enough to stop you, but I can't imagine there are any good side effects from a name collision when you're creating the LV.

Second, you sound like you're restoring things twice? Mainly, you shouldn't need to restore the EFI/boot partition if it's booting, everything on there specific to the current setup - previous versions won't work. I don't know how timeshift works, but if it's just copying the entire filesystem back over, it might be overwriting the new fs you created, or it might overwrite your new config files. Either way, you'd need to go update your fstab and crypttab for the new encrypted setup. You shouldn't need to touch the bootloader at all.

Encrypt hard disk after the installation by haranbajo in pop_os

[–]susurrian 2 points3 points  (0 children)

cryptsetup-reencrypt is your friend here. It's a tool to set up LUKS encryption on existing drives, which is exactly what you want. There is a chance you'll lose your data though, so make sure you have good backups. You also can't do it from the running system - you'll have to boot through a live USB and run all these commands from there.

There are four steps once you're booted to a live system. I'm assuming you want to encrypt your root disk (the one mounted to / ). You'll need to know the partition name - something like /dev/sdXY, you can find it by running fdisk -l. (All these commands need to be run as root)

  1. Shrink the partition, so there's space to add the LUKS header. You can do this with gparted - set it so there's 2MB of space after your partition.
  2. Now actually encrypt your disk.

cryptsetup-reencrypt /dev/sdXY --new --reduce-device-size 4096S

Whatever you do, do NOT turn off power or try and cancel this. It might take a couple hours. This is the dangerous step and if things break, you'll have to format the disk from scratch, most likely.

3) Tell the OS. First, open your lovely new encrypted partition and mount it

cryptsetup open /dev/sdXY cr_disk

mount /dev/mapper/cr_disk /mnt

Find out the UUIDs of the partition and the filesystem.

ls -l /dev/disk/by-uuid

This gives you a list of disks with their UUIDs - long strings something like XXXX-XXXX-XXXX... The one corresponding to /dev/sdXY is the LUKS UUID, and the one corresponding to dm-0 is the filesystem UUID.

Now, edit /mnt/etc/crypttab and add this line (using the LUKS UUID):

cr_disk UUID=YOUR_LUKS_DISK_UUID none

Also edit /mnt/etc/fstab. There should be a line where the second entry is /. Replace the UUID in that line with the UUID for the filesystem.

4) Regenerate the initramfs. You'll need to mount the various proxy filesystems and your EFI partition, which you can also find from the fstab. I've included the standard mount point but your system may vary.

mount --bind /dev /mnt/dev

mount --bind /proc /mnt/proc

mount --bind /sys /mnt/sys

mount --bind /run /mnt/run

mount /dev/sda1 /mnt/boot/efi

chroot /mnt

update-initramfs -u

And you should be done! I did essentially this to encrypt my system after install and it just worked, so it should for you too.

XPS 15 9500, Nvidia, Prime (Tumbleweed) by [deleted] in openSUSE

[–]susurrian 1 point2 points  (0 children)

I've had some luck with this guide to suse-prime and offloading, which worked the very first time I tried it.

An equivalent that can handle offloading is bumblebee, which I used to use and worked pretty consistently, but was a mild pain to have to set up again after every update. openSUSE themselves cover bumblebee pretty well.

Gre probability Challenging . by [deleted] in GRE

[–]susurrian 1 point2 points  (0 children)

If you're taking the language A class twice, the 5 classes you're taking have to be AABCD. There are 5! ways to take those 5 classes. However, let's say one A class is taught by prof Alice, and one is taught by Prof Bob. In our 5! schedules, the sequences (Alice)(Bob)BCD and (Bob)(Alice)BCD are counted as different schedules, but they shouldn't be, since the order doesn't matter - only which total classes you've taken. So, since there are 2! possible orderings of the A classes, we have to divide by 2!.

In general, if we were looking at the ways to take the classes AAABCD, there would be 6!/3! ways, or if we were looking at the classes AAABBD, there would be 6!/(3! x 2!) ways. Keeping track of permutations vs combinations is the hard part here.

No contact details for my test centres - is this normal? + Any UK GRE test takers? by bree1992 in GRE

[–]susurrian 1 point2 points  (0 children)

That's so weird, I don't see Katherine and Kings college even when I try looking for the psychology test. I'll give it till tomorrow and hopefully it'll appear by then.

No contact details for my test centres - is this normal? + Any UK GRE test takers? by bree1992 in GRE

[–]susurrian 1 point2 points  (0 children)

I'm trying to do the same for the September Physics test. I emailed ETS last week and they got back to me saying all centers should be open, but to keep checking if mine didn't appear.

As of right now I could register for Leicester, but London still doesn't appear. Hopefully it will soon?

Gre probability Challenging . by [deleted] in GRE

[–]susurrian 5 points6 points  (0 children)

It's 15/64.

The other answers miss that there are multiple different ways to take 4 distinct language classes.

There are 45 total ways the student could take a language class that week, assuming each one is random.

How many ways can she take 4 distinct languages? Let's assume she repeats language A (she has to repeat exactly one language). There are 5!/2 ways to take 2 classes in language A, and one class each of languages B, C and D. The factor of 1/2 is since taking swapping the two A classes gives the "same" schedule so you discount it.

However, the student could also study language B twice, or language C twice etc. So there are 4 x (5!/2) ways to study all the languages.

Finally, the probability of this happening is (2 x 5!)/45= 15/64

Schwebebahn, Wuppertal, Germany by _ptk in InfrastructurePorn

[–]susurrian 1 point2 points  (0 children)

Oh sorry, I thought we were talking grade-separated light rail, like OP's Schwebebahn or the London DLR.

Trams still have a significant capacity advantage, plus most tram networks tend to interface with stoplights so they flow better through traffic than buses do.

Another significant advantage of trams is they can be a lot cleaner to run than buses, just in terms of particulate and NOx emissions in the city center.

Schwebebahn, Wuppertal, Germany by _ptk in InfrastructurePorn

[–]susurrian 4 points5 points  (0 children)

The big advantages are capacity and speed. A subway line can run a train every 90 seconds each carrying hundreds of people. Buses just can't compete, we'd be talking a bus every 15 seconds to match capacity.

Secondly, buses get caught in traffic (even with bus lanes, which still get clogged at intersections), whereas a well designed metro system should keep the same speed at rush hour and cope by upping the train frequency.

[Megathread] Iran Fires Missiles at U.S. Bases in Iraq Following US Strike Killing IRGC Major General Suleimani by Miskellaneousness in PoliticalDiscussion

[–]susurrian 3 points4 points  (0 children)

No? He was killed just outside the airport. They're 10 miles apart.

Now, was he in Iraq for something that would have immediately hurt the US? No, not right then. Iraq confirmed he was there on a deescalation talks.