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abduhl commented on US Coast Guard Report on Titan Submersible   news.uscg.mil/Press-Relea... · Posted by u/rwmj
jjk166 · 17 days ago
400 MPa is better than the best structural steel. 1000 MPa is not for structural steel, it is for high grade steel, the sort you make submarines out of. Why would I list 400 and 1000 for the same value?

Steel is weaker in compression than tension. It's more isotropic than say concrete, but the difference is meaningful in practice.

We're not discussing rupture here. That's for when the pressure is higher internally than externally. We are discussing a submarine, which is a pressure vessel under compression which must also remain buoyant. The specific yield compressive strength is the value which matters.

abduhl · 6 days ago
When someone says "structural steel" they are normally talking about something similar to A572. A572 comes in multiple grades, with grade 42 being the lowest. Grade 42 has a yield strength of 42 ksi (hence grade 42) and a rupture strength of 60 ksi by spec. 60 ksi is 414 MPa. Even A36 (which is basically the weakest structural steel commercially available nowadays) has a rupture strength of around 60 ksi and a yield strength of 36 ksi. Hence, even the weakest "structural steels" have a rupture strength of around 400 MPa.

When I use the word "rupture" I am talking about the material property, not the specific submarine loading condition at play. When comparing steel, which is a ductile material, to carbon fiber, which is a brittle material, you should use the steel's rupture strength instead of yield strength. Steel is for all intents and purposes an isotropic material, and the difference between tensile strength and compressive strength is not material in practice (because steel in compression is nearly always governed by macro-scale geometric issues leading to buckling rather than the material strength in compression being exceeded).

abduhl commented on T-Mobile claimed selling location data without consent is legal–judges disagree   arstechnica.com/tech-poli... · Posted by u/Bender
fn-mote · 6 days ago
Include the time frame when you talk about this.

2007-present, in this case

People making conclusions should look at the data, though.

In this case, every ciruit has a 64+% reversal rate, the sixth has a reversal rate almost identical to the 9th. I have no idea what a significant difference would be.

Maybe someone can explain a set of assumptions and the resulting variance.

abduhl · 6 days ago
I didn't choose the data set or the link, perhaps your admonishment should be levied against GP.

I agree that people should look at the data before making conclusions, which is why I posted that the data directly contradicted GP's claim that the 9th "usually has the lowest, or among the lowest, reversal rate of any district." It doesn't. Based on the data, it has not only the highest reversal rate but also the highest amount of reversals. I take no position on whether the 9th's reversal rate is significantly different than any other circuit's other than to note that it is the highest by all reported metrics and that when you hear that fact, it isn't a "lie" (as characterized by the GP).

abduhl commented on T-Mobile claimed selling location data without consent is legal–judges disagree   arstechnica.com/tech-poli... · Posted by u/Bender
kstrauser · 6 days ago
If that were the case, then it would probably stand. The Ninth usually has the lowest, or among the lowest, reversal rate of any district: https://ballotpedia.org/SCOTUS_case_reversal_rates_(2007_-_P...

You hear a lot of lies to the contrary that it has the highest number of reversals, which is misleadingly irrelevant because the Ninth also has by far the greatest number of decisions. It's like saying that New York City has more violent crimes than El Paso, which utterly ignores the population difference between the two.

abduhl · 6 days ago
Your link says that the 9th is the most reversed circuit both in terms of raw reversals (196) and as a rate (79.4%).
abduhl commented on Stanford to continue legacy admissions and withdraw from Cal Grants   forbes.com/sites/michaelt... · Posted by u/hhs
hn_throwaway_99 · 15 days ago
> Their benefit is also much clearer, the $10M donation you mentioned can clearly and directly help a lot of students.

The benefit is clear, I would argue the detriment is also clear: Stanford is arguing that bribery is an acceptable method of doing business, not something that deserves opprobrium.

abduhl commented on US Coast Guard Report on Titan Submersible   news.uscg.mil/Press-Relea... · Posted by u/rwmj
jjk166 · 19 days ago
I would not call 400 MPa "very low" that's better than the best structural steel. Further, the important thing is the specific strength. CFRP has a density 5 times lower than steel, meaning you can use 5 times as much for the same weight, bearing 5 times the load. A good steel has a compressive strength around 1000 MPa, the best superalloys have compressive strength around 1500 MPa, the same weight of CFRP can withstand the equivalent of around 2000 MPa.

Sure this is idealized, but so is the strength of steel.

The concern with carbon fiber is its potential for delamination, not its compressive strength. Titan's failure was after delamination.

abduhl · 19 days ago
400 MPa is not better than the best structural steel. And 1000 MPa is way higher than the best structural steel (compressive strength and tensile strength are essentially equal for steel). Most structural steel has an ultimate tensile strength of around 500 MPa. Ultimate tensile strength is the comparable strength parameter when discussing rupture/fracture.
abduhl commented on The untold impact of cancellation   pretty.direct/impact... · Posted by u/cbeach
kanbara · 23 days ago
>propaganda

you mean a movement where an entire half of the population have been treated as less than, coerced, not has the same rights, earn less money, and are still routinely demonized with 2000 year old paleolithic thinking?

why do men think they can get away with everything, and that the moment women try to speak up they are evil?

abduhl · 22 days ago
It’s funny because if you delete your last sentence (or just remove the sexes) this post could be a choose your own adventure prompt for anyone to drop their own views/prejudices into.
abduhl commented on Australia widens teen social media ban to YouTube, scraps exemption   reuters.com/legal/litigat... · Posted by u/Brajeshwar
shakna · 25 days ago
> Who's in charge here, you or your kids?

As a parent you're not in charge of a teenager. You're there to guide them, and try to protect them from their bad choices, but they have reached a point where they are beginning to control their self-determinism. They're not a kid anymore.

If you just try to act the authority, try to control everything, then well... You'll either end up in abusive land, or trying to control someone who has learnt to hate you for not treating them as a person who does have their own sense of self.

abduhl · 25 days ago
You are, in fact, in charge of your teenager as a parent. They are, in fact, still a kid. Controlling your kid’s access to things which you deem harmful is, in fact, not abusive. Setting appropriate boundaries does not, in fact, mean you are not treating your kid as a person who has their own sense of self. Most kids will not, in fact, hate you for setting boundaries and being their parent.

It is quite impressive that nearly everything you’ve typed is incorrect.

abduhl commented on     · Posted by u/mikhael
abduhl · a month ago
I despise “articles” like this. It is an article based on a Reddit post of another article which 1) quotes a couple Reddit users and 2) links to the original article linked to in the Reddit post. It has almost zero original content and zero substantive original content. I’d rather read AI slop.

Here is the original informative article: https://www.cbc.ca/news/canada/affordable-vacation-canada-1....

abduhl commented on Why Writing by Hand Is Better for Memory and Learning   scientificamerican.com/ar... · Posted by u/andsoitis
John7878781 · 3 months ago
> How is your learning harmed?

One's goal when studying is to optimize learning as a function of time. When note-taking is forced, this goal becomes impossible for me. I spend time taking notes when I could be spending time on more impactful study techniques (videos, practice sets, etc). To be clear, I think the notion that "notes are useless" only applies to specific groups of people. The bottom line is that everyone learns differently, and forcing a certain approach is an awful idea.

> How have you been disallowed from discovering what works best for you?

I would not say that I have been directly "disallowed," but undeniably, there are bandwidth constraints for students. If I'm taking multiple hard courses, I only have so much time to spend. If I am spending my time note-taking, which my teacher requires to turn in to him/her, then I have less time to do other, more productive things with my time. I think naturally, freedom spurs efficiency. Free and competitive markets are more efficient than command economies. Arguably, this same principle holds true on an individual level.

abduhl · 3 months ago
>> If I'm taking multiple hard courses, I only have so much time to spend.

You’re in high school. No course is hard.

>> Free and competitive markets are more efficient than command economies. Arguably, this same principle holds true on an individual level.

This is a silly statement. Free and competitive markets are not always more efficient than command economies, and they certainly aren’t as you move away from a market to a market unit. So, no, your erroneous principle does not arguably hold true on an individual basis. There is a reason that corporations are structured more like a command economy than a free market.

abduhl commented on Why Writing by Hand Is Better for Memory and Learning   scientificamerican.com/ar... · Posted by u/andsoitis
John7878781 · 3 months ago
Generally, it is true that writing by hand is better for recall and memory. However, teachers often use this as a justification to force students to handwrite everything, which can be very counterproductive for a subset of students.

I am currently in high school and have taken 17 AP classes. I have tried taking notes time and time again and have consistently found that they do not help me at all. I have a 3.99 GPA, 1570/1600 SAT, and have received 5s on all of my AP Exams. I know how to study and know what works best for me. I am not a notes person, and when teachers force their "scientific" teaching methods upon me, it does nothing but harm my learning and waste time.

I love the idea of science being incorporated into learning but we need to make sure students are allowed to discover what works best for them.

abduhl · 3 months ago
How is your learning harmed? How have you been disallowed from discovering what works best for you?

u/abduhl

KarmaCake day3235July 11, 2011
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shalmanese 1 hour ago | undown | parent | flag | favorite | on: Operation Luigi: How I hacked my friend without he...

One of my favorite low key social engineering hacks is that I used to have a keylogger installed on every machine I own. Whenever a friend needs to hop on my machine to show me something, they'd log into an account they own and I would have their password.

Then I'd do the same Luigi-like low key messing with them for a while. My favorite was when a friend had a VNC server running on their machine with control capabilities. I would sit next to them and subtly jerk the mouse pointer right before they were about to click on something and it drove them mad for a good 20 minutes before I couldn't hold onto the giggles anymore.

edit: To add a bit of context, this was in the Windows 98 era, before the age of social media where we started putting all of our secrets onto our machines. And it was among a group of friends where everyone was trying to hack everyone else and pretty much anything was considered fair game. All of us were high school kids so there wasn't some super serious reputation we had to protect.

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