The h Bar

Anonymous

7:19 AM

Any idea about this question?

Anonymous

chemistry.stackexchange.com/questions/72778/…

Anonymous

The answerer seems to have completely missed my point...

Anonymous

@blue, I think I see your point. Your issue isn't with reaction order, but the rate constant definition. To summarize your argument: say our reaction is $\ce{A -> B}$ and $k$ = 10 s$^{-1}$, but if our reaction is $\ce{2A -> 2B}$, then $k$ would be 5 s$^{-1}$. The half-life of species A remains the same in either case, being $t_{1/2} = \ln 2/k$ in the former and $t_{1/2} = \ln 2/2k$ in the latter, but the reaction rate constant is different. Is that right? I think your argument is sound, but I'd like to see what others have to say. — a-cyclohexane-molecule 54 mins ago

user228700

@JohnRennie I uploaded one :-)

user228700

I think I know what happened; I used a software to change some of the details of the books which may have "corrupted" them.

John Rennie

7:26 AM

@Kaumudi.H YHM

Pro-tip: .epub files are actually just .zip files renamed.

user228700

What did u change..?

John Rennie

If you rename them to .zip you can extract them, make any changes you want then zip them up again and rename them back to .epub.

user228700

Also, I should mention that another reader also didn't recognise it.

John Rennie

@Kaumudi.H The file you uploaded opens fine with Aldiko on my tablet. Does the version I mailed you about open on your phone?

user228700

@JohnRennie Yes, it does...

user228700

7:39 AM

Does it really open in ur Aldiko? (The one that I sent)

John Rennie

@Kaumudi.H Yes. Weird - I'm not sure what was going on there. In any case your version has the line breaks messed up.

user228700

:-( I have twenty such books! Not even the HP books are being recognised!

user228700

Sigh. I bet it's that stupid program "EPubor Ultimate" that screwed me over.

John Rennie

I wonder if the file name has a space at the end i.e. it's ".epub<space>"

user228700

Huh? O_o How to discern if it has a space at the end?!

John Rennie

7:43 AM

The curious thing is that I don't think the Import screen in Aldiko opens the files until you actually tap the Import button. It should just all files that end in .epub regardless of what they contain.

user228700

That's the problem! It doesn't even show any files!

John Rennie

Download ES File Explorer. You can use that to see exactly what is in the Downloads folder.

Or connect the phone to the laptop and use the laptop to see what is in the Downloads folder.

user228700

I'm able to see on my phone that they're present in the downloads folder when I check outside of Aldiko, like I said before...

Slereah

"If the universal cover is not taken, (p, q) anti-de Sitter space has O(p, q + 1) as its isometry group. If the universal cover is taken the isometry group is a cover of O(p, q + 1)"

user228700

Also, YHM!

Slereah

7:46 AM

What is the cover of anti de Sitter D:

John Rennie

My recommendation is to use the laptop for downloading books. I think I installed an epub reader on the laptop, so you can open the downloaded files to check them. Then copy the files over to a folder you create for the purpose e.g. /Books and use Aldiko to import them from there.

user228700

Wokay. Thanks for all this help :-)

Slereah

Oh wait

I guess the way AdS is defined in physics usually, it is rolled up, if you will

Anonymous

Why is Kinetic Energy equal to Potential Energy for waves on a string?

Anonymous

Is that statement true at all?

Slereah

7:50 AM

So the universal cover is the actual hyperboloid sheet

GPhys

8:02 AM

1 hr indico.cern.ch/event/580620

Secret

@GPhys Who cares, because the quantum apple is super delicious!

user228700

@JohnR: Why are so incredibly helping/generous? :-P

Secret

Last night dream most weird thing: An interstellar fashion tsunami that flows upside down above our heads

John Rennie

@Kaumudi.H I wouldn't say I was incredibly helpful, just everyday helpful :-) It's not as though it costs me anything but time, and I have plenty of spare time since I quit full time work.

user228700

Gah, your modesty is irritating at times. There is no denying that it was kind of you to choose to help me in that spare time rather than do literally anything else.

John Rennie

8:17 AM

I suppose I have a missionary zeal to convert everyone in the world to a nerd (physics or computer flavoured nerd). And I have to concede it's gratifying to have others ask your advice on things. It implies a level of respect for one's knowledge :-)

Slereah

Try the other way around, perhaps

try insulting him

maybe he'll compliment himself

user228700

@JohnRennie Indeed it does :-)

Secret

The Upside down tsunami:

The dream managed to fool me this looks normal because of how it extend all the way to the floor, thus can still be interpreted as the whole bulk of the water get sucked up and curved as follows due to the huge force in the tsunami, leaving a shallow puddle behind that still touches the floor

But if you think more closely, the centripetal and other forces have to be so large to overcome the downward pull of Earth's gravity, thus such a scene is highly implusible

(and yes, my head is briefly underwater because the (upside down) water surface is so low due to the travelling hump)

GPhys

8:35 AM

The pdf of the new LHCb results is up! indico.cern.ch/event/580620/attachments/1442409/2226501/…

see indico.cern.ch/event/580620 for the seminar in 25 minutes if you're interested

summary slide, 2.2-2.5 sigma deviation from SM

here is the money plot

Slereah

So what's wrong

Is it gonna be PCT symmetry again

Kaons always fuck up PCT

John Rennie

Brace yourself for about 1,000 papers proposing mechanisms for the discrepancy :-)

Slereah

Is it gonna be a loose cable again

Secret

So, what is the expected $\mathcal{R}_{K^{*0}}$ if there is no new physics, is it 1.0?

GPhys

@Secret the "SM" plot points here are giving calculated standard model predictions from various programs

Slereah

8:42 AM

Also what is $\mathcal{R}_{K^{*0}}$

Secret

O sorry, I read too much into the colorful dots, I think I can see it now why it might be significant.

But until they can get that to $5\sigma$, it could fade away just like the 750 GeV diphoton signal

GPhys

@Slereah it's a ratio of something in the measurements, I need to see the fuller paper or finish rereading the slides more carefully to tell you exactly

these slides tend to be arcane if you are not very well educated on the even the HEP subtopic, but the internal CERN notes are usually much better so I read those instead

the eventually published paper is okay, but the internal CERN notes contain all the stuff that's too "easy" to put into the published paper

@Slereah Here it is

Secret

Hmm so the results means the decay channel to electron is ~1.5 times more likely than the decay channel to muons?

Slereah

So weak decay sort of ratio?

why is the weak interaction so awful

GPhys

9:03 AM

webcast starting now indico.cern.ch/event/580620

audio man saves day \o/

JohnSmith

Hi! I'm new to StackExchange!

Sanya

9:31 AM

@JohnSmith welcome \o/

user228700

9:52 AM

@JohnSmith Hello and welcome! :-)

Dartek12

10:49 AM

hello, Im just having some doubts about how to make correct notation of my experience's result, using reglinp i've got my b coefficient and it's -6,83E-17 mV, while the uncertainty of this is 0,0086 mV

shall I write 0,0000(86) mV as a result?

Slereah

I want off this ride

Ramanujan

11:01 AM

Hello @JohnRennie

John Rennie

@Ramanujan Hi

Ramanujan

@JohnRennie, Can three forces of 5N, 8N and 14N acting on a body produce a zero resultant?

@JohnRennie, 1). Yes, 2). no. 3). Depends on time. 4). Depends on mass

paracresol

@Secret Gee, you're quite imaginative ;)

John Rennie

@Ramanujan I'm generally willing to try and explain some concept in physics, but you have a tendency to just post a question with no indication of what work you've done on it or how you think it might be approached.

3

If you explained what you'd tried and where you got stuck that would be a better way to approach questions like this.

Ramanujan

@JohnRennie, I guess the answer is 'no'. But not sure

Fawad

11:07 AM

@JohnRennie and people said him before too

paracresol

"I'm generally willing to try and explain some concept in physics" How about my queries? Can I ping you (occasionally) too? [Disclaimer: My "Queries" are usually the long drawn out discussion-kind ones though ._.]

John Rennie

@paracresol yes, of course.

paracresol

in The Periodic Table, Jan 9 at 13:43, by Mithoron

@Ramanujan sigh could you stop asking bad questions?

@JohnRennie Yes!!! \o/

John Rennie

However bear in mind that I've forgotten much of the basic physics I learned 40 (!!!) years ago so my knowledge is a bit patchy :-)

Fawad

@paracresol sorry but no question is bad

paracresol

11:10 AM

^^ I'm still a high-schooler, so my physics is limited to those patches ;)

@Fawad There's no stupid question (generally speaking), but there are certainly very bad questions out there :]

John Rennie

@Fawad I disagree, though I probably wouldn't use the words good and bad. A question is useful if you will learn something from the answer. If you're just going to write that answer in your homework book then it wasn't a useful question.

2

Fawad

@JohnRennie agreed

Ramanujan

@JohnRennie, I am preparing for competitive exams and so don't have any formal classes to learn the concepts and thus directly go by exercises

paracresol

@0celouvsky were you @0celo7 by any chance?

0celouvsky

Why does everyone think that?

John Rennie

11:14 AM

@Ramanujan so explain how you approached the problem, then we can comment on whether your approach is correct or not.

paracresol

Great, it's confirmed then! Hi 0celo7! o/

@JohnR Another query?

What is Planck's Radiation Law? By that, I mean the original statement that Planck (supposedly) provided, or is it even a "statement" at all? I've run multiple searches online, consulted several books but none of them provide any sort of statement though ._.

Ramanujan

@JohnRennie, Actually I think that it depends on mass of body. Bcoz. It may be possible that a body has 0 acceleration. Suppose three men pushing a wall with forces 8N, 5N and 14N. The wall will have 0 acceleration.

paracresol

Wikipedia mentions:

> Planck's law describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature T

My Oxford Science Dictionary says:

> This law gives the spectral distribution of energy emitted through black body radiation

^ Which isn't very different from the Wikipedia version.

Like I said, what bugs me is the absence of any explicit "statement" :(

I mean, I understand Planck's Law, but whenever I ask myself the question "State Planck's Law." I strongly feel like punching myself in the face out of frustration >_<

John Rennie

@paracresol: momentarily busy, back in a mo ...

paracresol

^ Yeah I noticed, I can wait ;)

Secret

11:20 AM

> That is like comparing an uncountable set with a countable set, which is nothing compared to koolman's

(The above message is intentionally nonlocal)

John Rennie

@paracresol: this law?

Planck's law

Planck's law describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature T. The law is named after Max Planck, who proposed it in 1900. It is a pioneering result of modern physics and quantum theory. The spectral radiance of a body, Bν, describes the amount of energy it gives off as radiation of different frequencies. It is measured in terms of the power emitted per unit area of the body, per unit solid angle that the radiation is measured over, per unit frequency. Planck showed that the spectral radiance of a body for frequency...

paracresol

^ Yeah, that one!

John Rennie

What are you asking about it?

paracresol

Gimme a second

@JohnRennie I was hoping to find the "statement" of the law (if it exists). That sounds kinda obscure, sorry; for example, the "Statement" of Newton's 2nd Law goes like: In an inertial reference frame, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma.

0celouvsky

@paracresol who are you

paracresol

11:29 AM

@0celouvsky A guy you bugged/helped a long time ago ._.

0celouvsky

???

Who

paracresol

^ Um...me?

This is confusing...

John Rennie

Planck's law is actually an example of a probability distribution. So I guess it is a mathematical object rather than a simple law. It is analogous to the Fermi-Dirac and Bose-Einstein distributions.

paracresol

^ Done! Thanks for confirming that!

Oct 12 '16 at 4:41, by Aaron Abraham

@DavidZ I have experience......he did it to me when I was inquiring about Noether's theorem :P @0celo7

Secret

Is there a metacresol?

paracresol

11:33 AM

Well, there was a metacresol >_<

Slereah

@0celouvsky writing out the boosted Alcubierre was a mistake