The h Bar

JamalS

12:32 AM

@ACuriousMind My latest question was probably made for you :)

David Z

12:42 AM

0

Q: Calculating current and voltage using superposition

I'm trying to calculate Vo and Io from the following circuit: Circuit I was using node analysis but I don't really know how that worked. A friend of me told me that I could better us superposition. I understand that I have to calculate the current for each generator with the others excluded (op...

network

I think that should be closed under our homework reason but I don't want to do it unilaterally

heather

vtc'd as homework.

DanielSank

1:49 AM

Hi, everybody.

heather

@DanielSank, hello

i looked up lisp

and I got intrigued

so I'm messing with it a bit. =)

it's cool!

DanielSank

never tried it

heather

it's fun

I've just received word that the Emperor has dissolved the MIT computer science program permanently.

=)

DanielSank

heh

I read the last line in Alec Guiness's voice.

heather

2:27 AM

i don't know who that is =/

oh, guy who played obi-wan's voice

okay

DanielSank

2:39 AM

i.imgur.com/MvNpD9C.gifv

@heather !!!!!!!!

;oij poi908eoi;ew[ we

[paer;'a;oiuae wr[09u e

Obi-Wan's voice?

Kids today...

Alec Guiness played Obi-Wan in the original Star Wars trilogy.

Sir Cumference

Howdy

Alfred Centauri

@DavidZ I see that the question is migrated in and that the OP has no account here. I just posted a comment (and voted to close) but now I wonder if the OP is notified in the case of no account.

@Kenshin only living beings can value and have values.

Sir Cumference

@AlfredCentauri Why aren't you wearing a hat

Alfred Centauri

@SirCumference I don't know; do you have a recommendation?

Sir Cumference

2:55 AM

I would've suggested the "where in the world", but you might've missed out on that...

DanielSank

There should be an octopus hat.

heather

there should be.

octopi are great.

DanielSank

Yes they are.

user116211

0

Q: What is saturation density and nuclear drip point?

What is meant by nuclear saturation density and neutron-drip point? How can we relate the both densities? Where do these densities occur in the layers of neutron star and by what reactions a star has to pass to reach at the neutron-drip point and saturation density?

condensed-matter nuclear-physics astrophysics terminology neutron-stars

user116211

Dearth of research-efforts?

Secret

3:22 AM

5 hours ago, by Slereah

-7

Q: I don't know what this is

I had this picture that mysteriously appeared on my phone and ive sent to a couple of paranormal people and I don't know who took it or why but there appears to be a black funnel looking thing in the background of my living room and I was just surfing the net and came across worm holes and I thou...

wormholes

Suppose this is a smoky wormhole funnel, what is it doing in someone's bedroom...?
(More likely than hoax I guess)

Nah, real wormholes don't look like funnels

Sir Cumference

@AlfredCentauri You there?

Alfred Centauri

@SirCumference Just got here

Sir Cumference

@AlfredCentauri There's a hat I think would look good for you

You get it by upvoting a post within the next 1.5 hours

Tell me when ya did that

Alfred Centauri

@SirCumference Thanks for that heads err... hats up. I'll check it out.

2

OK, done

Sir Cumference

3:40 AM

@AlfredCentauri Give it a few mins

That hat has two versions, and it's random which one you'll get

@AlfredCentauri Cool, you got the one I was hoping for

Alfred Centauri

@SirCumference oh, that is a nice hat. Thank you sir!

user228700

4:29 AM

Hi, everyone :-) Does anybody know any inorganic chemistry? I was wondering about oxidation states and exactly what the heck these numbers are used for...it seems like they're just s'thing we made up and heh, this is what my textbook says:

user228700

> "Even covalent bonds are assumed to be ionic. Caution: This imaginary and not the real picture"

DHMO

@Kaumudi.H yes, oxidation number is something we made up.

user228700

Dang it, these Chemists :-/

Pissed off layman

some would say the negative numbers are made up

user228700

Ah, that's exactly the kind of thing that one would expect a Pissed off layman to say :-)

Pissed off layman

4:43 AM

;-)

DHMO

@Kaumudi.H but it is useful for tracing oxidation/reduction

Pissed off layman

+ there is no "real" picture when it comes to electrons.

user228700

@DHMO Yeah :-| Thanks.

user228700

@Pissedofflayman Yeah :-/

Pissed off layman

Just memorize it like the rules of a "game" ;-)

user228700

4:52 AM

Yo, @Kenshin: Check out this paragraph from my amazing textbook of amazing:

user228700

user228700

It's so good that I'm willing to describe it using the sketchy (af) phrase: "I can't even."

Pissed off layman

What do you mean?

DanielSank

Oh my goodness I did it.

I implemented a complete asynchronous event loop from scratch.

I've been trying to learn this for years.

Pissed off layman

5:12 AM

Congrats!

Sir Cumference

@Piss You haven't registered?

Pissed off layman

Nope.

Sir Cumference

You should

Pissed off layman

I'm not sure I want to be apart of a community that does this:

in Mathematics, 17 mins ago, by TheGreatDuck

i am notifying you and the moderators that the username violates site guidelines

Sir Cumference

@Pissedofflayman I guess your name is more accurate in this case...

Pissed off layman

5:27 AM

...indeed.

Sir Cumference

@Pissedofflayman Eh, ignore people like that

Pissed off layman

Always have and always will ;-)

Secret

5:52 AM

1

Q: The historical credits of Renormalization Group

Polyakov remembers the development of Renormalization Group and Conformal Bootstrap as "With the use of the ingenious technique, developed by Gribov and Migdal [1] in the problem of reggeons, I found connections between phenomenological theory and “bootstrap” equations (Polyakov [2]). Sasha Mi...

quantum-field-theory conformal-field-theory critical-phenomena conformal-bootstrap renormalization-group

migrate to hsm since its mostly ask about the historical contributions?

user228700

6:08 AM

@JohnRennie: DID U CHECK THE WEBSITE AAAAAAH!!!

John Rennie

@Kaumudi.H IT'S IN CHENNAI

koolman

@Kaumudi.H on what date you expect to recieve the laptop

user228700

YAS, IT IS AT THE DEPOT NEAREST TO MY HOME AAAAAH!!!

John Rennie

Delivery tomorrow then!

user228700

-______- U're kidding, right?

John Rennie

6:11 AM

Just in time for Christmas (which of course you don't celebrate :-)

user228700

U were joking, right?

John Rennie

@Kaumudi.H are you thinking it might arrive today? It could just about. The last note was 11:02.

Have you been told what duty needs to be paid?

user228700

11:02 was like, 40 minutes ago!

user228700

So I feel like it should most definitely arrive today! I don't think there are any other procedures...

user228700

@JohnRennie They told us that it's about Rs. 1500 last week, but no, they haven't updated us since and they told us that we'll need to pay it to the deliveryman.

user228700

6:14 AM

Why dyou think it'll only arrive tomorrow?

John Rennie

In the UK the local couriers normally leave the depot around 9 a.m. so in the UK the delivery wouldn't arrive until tomorrow. It would be great if it arrives today, but don't be too downhearted if doesn't.

user228700

Oh, I see. I don't know if that's how it works here. My gut says it'll be here soon (as in, in the next few hours) We'll see :-)

Sir Cumference

6:26 AM

@JohnRennie Dang, you don't celebrate Christmas? :/

I don't either. I've heard it's cool though.

John Rennie

@SirCumference yes I celebrate Christmas but then I'm (notionally at least) a Christian. Whether Christmas is any cooler than Devali or Pongal is debatable.

Sir Cumference

Oh crud, meant to reply to Kaumadi

user228700

:-P No, @SirCumference: We're not Christians.

Sir Cumference

@Kaumudi.H Wait hold on

Are you the same Kaumadi as before?

Never realized. I always associate people here with their gravatars...

user228700

@SirCumference x'D Yep. Aren't u that guy who naps for too long, then hates himself during the night?

2

Sir Cumference

6:30 AM

Confuses the hell out of me when someone changes it

@Kaumudi.H That's what I'm known for now... ;-;

user228700

Aw x'D

Sir Cumference

Well it's better than my reputation a year ago

Nov 14 '15 at 17:57, by 0celo7

Oh the pun man who cant do calculus

Now I'm just the pun man who can't sleep

user228700

@SirCumference Yeah, that's (arguably) a lot better.

Sir Cumference

@Kaumudi.H Say, you gonna try to get that Snaphat hat? It'd look perfect on your gravatar

user228700

No, I don't understand what's happening with all these hats...

Sir Cumference

6:34 AM

Oh woah

user228700

(And it's been awhile since I asked/answered any questions)

Sir Cumference

You weren't around for last year's, right?

OK, the idea is you go around doing stuff, and you get hats you can put on your gravatar

user228700

Nope. I joined SE this April.

Sir Cumference

For example, try upvoting a post right now

user228700

Just... upvoting?

Sir Cumference

6:36 AM

Yep

user228700

Um, okay...

Sir Cumference

Then wait a few mins. Congrats, you got a hat for doing something on the winter solstice.

John Rennie

It isn't the solstice in India. That was yesterday.

Sir Cumference

It just needs to be solstice somewhere in the world when you upvote it

Anyway, here's the list of hats (not counting secret ones, you can google those)

@JohnRennie Speaking of which, how'd you get "Blue in the Face"?

John Rennie

@SirCumference I don't know. When you get a secret hat you aren't told why you got it. I think it might have been something to do with commenting.

Sir Cumference

6:41 AM

:/

user228700

I'm on my mobile. Please let me know if a hat appears for me...

user228700

(There's no way I'm getting the Snaphat BTW)

user228700

In fact, I don't do much on the main site these days. I'm not gonna be getting any hats apart from Cutting the cord, perhaps.

user228700

The last time I asked a question was about 2 months ago. @JohnRennie spoiled me :-P

John Rennie

@Kaumudi.H you have four hats:

user228700

6:53 AM

Wtf?!?!

user228700

I'm not able to see them :-/

John Rennie

Try physics.stackexchange.com/users/106570/kaumudi-h#winter-bash

user228700

Nope :-/

John Rennie

Well, when your laptop arrives ... :-)

user228700

Do these hats go away or can I have them till whenever the Winter Bash ends?

John Rennie

6:57 AM

They last till the Winter Bash ends (in early January some time)

user228700

Awesome :-)

John Rennie

Incidentally, oxidation number is very important for tracking redox reactions i.e. how electrons move.

The oxidation number tells us the redox reactions that have occurred compared to the elemental state.

user228700

@JohnRennie Yeah, that makes sense.

user228700

Also, I couldn't help it so I called TNT (Sorry!). They said "We'll try to deliver it by today".

John Rennie

@Kaumudi.H :: fingers crossed ::

user228700

7:09 AM

Yep!

user116211

Hey @JohnRennie, did you get the Elementary secret hat?

Sir Cumference

@Kaumudi.H There's a hat for voting on seven posts via the app

Oh nvm, you have it

user228700

@SirCumference Yes, I seem to have gotten not only that hat but also 3 other hats. I've no idea how to view them :-(

user116211

BTW, Community has earned 8 hats. Actually, didn't think Community would also get hats.

Sir Cumference

@MAFIA36790 Supposedly, Community having the secret "Don't Wanna Taco 'Bout it" hat is a hint on how to get it

@Kaumudi.H Not bummed you can't keep them?

user228700

7:16 AM

@SirCumference I can't?

Sir Cumference

@Kaumudi.H Not after early January

user116211

@Kaumudi.H You can keep a snapshot if you want.

user228700

@SirCumference Oh, well, I have a few more days. When the laptop gets here, I'll try to check it out.

Sir Cumference

@Kaumudi.H Try to get the hats from doing something on a special day (like Christmas, Hanukkah, etc.)

The list I gave you should have the dates

user228700

@SirCumference Will do, thanks! You're the only reason I have 'em :-P

Sir Cumference

7:20 AM

:3

John Rennie

7:42 AM

@MAFIA36790 no. How do you get that hat?

user116211

I got?

Secret

0

Q: Time dilation and twin paradox: If they twins were speaking on a phone of some kind, how would each other's voices sound?

don't get upset but I'm a total layperson and I'm not really understanding the twin paradox and I'm just wondering: If the twin who left earth in a rocket so that he wouldn't age as fast had a walkie talkie of some kind to contact the twin on earth with, would the twin on earth hear the spaceship...

special-relativity

delay

user116211

I checked; I didn't get @JohnRennie.

user116211

However, as the meta post deciphers:

user116211

> Edit 5 posts from 3 years ago or earlier

John Rennie

7:53 AM

@MAFIA36790 Ah OK.

I haven't been deliberately trying to get hats. Just business as usual and if a hat appears that's a bonus.

user116211

@JohnRennie yes, that's the fun.

user116211

You don't think of them too much; just do your daily site chore and they will do their job. Just enjoy without pondering about them on how to get and all that.

user116211

Anyway, I was dugging up Qmech's old posts and edited two or three of them. So, I thought I would get the Elementary hat; but it seems, they meant different posts from different users; I don't know. But that hat is really awesome.

user116211

0

Q: What is the cause and meaning of harmonics?

Let's suppose that a cantilever is vibrating at a frequency of 2Hz. That means that it goes up and it comes down twice per second. I don't understand what the term harmonic means. I can't grasp how the vibrating rod moves twice and, at the same time, four times or eight times per second. Descrip...

vibrations

user116211

On-topic?

user116211

7:59 AM

Isn't OP asking about harmonics? I think it can be found online, isn't it?

user116211

Hmm

user116211

@JohnRennie I'm seeing Qmech has the Elementary hat.

user116211

Seems reasonable as he edits old posts often.

Sir Cumference

@JohnRennie Oh, by the way

Do you ever recall seeing a formula in cosmology like

$g = \frac{-GM}{R^2} + \frac{1}{3}ΛR$

Describing the expansion of the universe?

John Rennie

@SirCumference That came up recently ...

Sir Cumference

8:14 AM

My professor said it describes the expansion speed of the Universe, but I can't find any such formula when looking it up online

John Rennie

2

A: Orbits in an universal expansion?

Using the equation conveniently proved in @AccidentalFourierTransform's answer on a related question (note: strange units): $$g=-\partial_r\Phi=-\frac{GM}{r^2}+\frac{1}{3}\Lambda r\tag{3}$$ Then we can calculate the radius at which the cosmological constants (CC; $\Lambda \approx 10^{-29} \textrm...

Sir Cumference

Oh wow

John Rennie

$g$ is an effective gravitational acceleration not the metric.

Sir Cumference

@JohnRennie Yeah, that's what I thought

Then I got myself confused

I'm wondering why I couldn't find it anywhere tho...

John Rennie

8:31 AM

@Kaumudi.H: the web site now says Held Awaiting Payment Of Duties/taxes Or Charges By Receiver

It might be worth ringing to make sure they aren't waiting for you to come to the depot and make the payment.

user228700

But now it says:

user228700

> "Shipment arrived at TNT location"

user228700

What is happening, hmm...

John Rennie

@Kaumudi.H it's probably nothing. But given how much aggravation this has been so far I'm thinking that it wouldn't hurt to be sure. Maybe you could go to the depot to collect?

user228700

When we called them earlier, the person on the other end told us that it would cost us Rs. 2300. That's about... £28.7 and asked if we had the money to hand.

user228700

8:39 AM

When we confirmed that yes, we do, they told us that they'd send it and that we'd have to pay it to the deliveryman.

John Rennie

Ah, OK,in that case I guess wait and see what happens

user228700

And then we asked when they'd deliver and they said that they'd try their best to deliver by today...

John Rennie

That's a high charge, but I suspect it is the import duty plus the sales tax.

user228700

Yeah. It's okay tho. Totally worth it :-D <3

user228700

The TNT depots are all quite far from my home...about 10-15 Kms and those are the nearest ones.

user228700

8:44 AM

@JohnRennie It's ridiculous that we'd have to do these things.

user228700

I've just realized that 10-15 Kms probably doesn't seem that far to u, but u dunno the amazing condition of our amazing roads :-P

John Rennie

@Kaumudi.H I gave up on expecting the world not to be ridiculous a long time ago. Sadly the world doesn't care what I think, so I just deal with it and get on with life :-)

user228700

:-) That's good advice: "Move on already, the universe doesn't care about u".

John Rennie

Have you got a spare plug to go on the power cable? It currently has a UK plug.

Though if the customs haven't run down the battery checking the laptop you'll get a few hours usage without needing the charger.

user116211

Speaking of bad things, did you hear about the assassination of Russian ambassador in Turkey and the Berlin Market blast, @JohnRennie? Why do they choose this part of the festive season? :(