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12:01 AM
Why the ---- does everyone say "Einstein's general relativity"?
Why does that theory always come with a person's name?
How about "Boltzmann's statistical mechanics"?
This hero-worship seems out of place in science.
 
user223506
hello @DanielSank!
 
@Doc Hi.
 
user223506
how are you going?
 
user223506
a question - this question:
 
user223506
1
Q: Does smog attenuate UVA more as compared to UVB?

AniruddhaI am trying to understand if winter smog has a greater impact on UVB radiation as compared to UVA radiation. I would loosely define winter smog to contain following: smoke and gases due to vehicular emissions smoke due to burning crop residues and biomass relative humidity at about 30% high pre...

 
12:06 AM
@Doc I am going well.
How are you going?
 
user223506
`I agree, as it stands it is far too broad - however, the OP says in his comment here
 
user223506
I agree that the question relates to a very broad subject. How about restricting it to attenuation of UVA/UVB by particulate matter only? I believe this will restrict it to scattering, which is certainly a physics topic. — Aniruddha yesterday
 
user223506
would be answerable
 
user223506
@DanielSank swimmingly!
 
user223506
that question above I could answer with the refienment the OP suggests - my question is, would it be okay if I were to edit in the refinement
 
12:11 AM
Of course.
That's why there's an "edit" button.
 
user223506
it wouldn't be too forward of me to do it?
 
No. The point of this site is to generate high quality physics questions and answers. If you can do something to contribute to that goal, do it.
Don't worry too much about preserving other people's egos.
If you make an improvement and someone else is upset, that's really mostly their problem.
 
user223506
that is very true
 
Obviously, we don't want to make people feel unhappy, but often if someone is upset by their post being edited, it's because they need to adjust their attitude.
Most of the time, if you make a good edit, the person who originally wrote the post will be very happy.
 
user223506
and in this case, I used the OP's comment as the basis
 
12:17 AM
@Doc You're worrying about this too much. Just make the edit. If the OP doesn't like it, they can roll it back.
 
hello
you and I are tied for hats @DanielSank =D
 
@heather I WILL BEAT YOU
 
whoa
 
WOAH
I just got another secret hat!!!!
 
user223506
@DanielSank true that - edit is made :)
 
12:22 AM
@DanielSank, how!?!?!
 
user223506
I have 14 hats
 
my leaderboard position ='(
 
@heather I don't know!!!
I got "elementary".
@AccidentalFourierTransform
@heather leader board?
 
what did you do?
before getting the hat?
 
@heather edits
How the crap does @AccidentalFourierTransform have thirty hats?
That's silly.
 
12:40 AM
no, that's awesome
edits...
i've done many edits.
 
I don't know what to tell you.
Have you seen the Google Doc where people are putting their theories/evidence?
> Confirmed - I just edited 7 questions older than 1 year on the Motor Vehicle site. I didn’t do anything for 10 minutes. BAM. Received this hat. (ducatikiller)
 
hmm, okay.
 
They need more octopus hats.
Also, they should do site-dependent hats, i.e. hats that you can only get for activity on a particular site.
 
they do! also more rocket hats.
 
Ours would be the Mexican hat, obviously.
 
12:46 AM
@DanielSank well, they do to some extent. they have the what's up doc hat.
 
That would be such a sick hat.
@heather ???
 
but a mexican hat would be so cool.
@DanielSank for getting an upvote on documentation on SO
oh, gtg, sorry! have a good night
 
@heather ohhhhhhh
@heather ciao
Dear SE Staff,
    Please don't take our hats.
    - Everyone
6
 
user223506
1:03 AM
love the hats!
3
 
we used to have sleigh rides too
into and out of the chatroom
very cool
:-)
 
user223506
that would be very cool indeed!
 
1:25 AM
Mwa ha ha ha @heather 18 hats!
5
 
user223506
18?!?!?
 
user223506
@DanielSank got to catch up with my 14 hats!
 
He's got enough hats for two octopuses.
 
@Doc That's nothing. AccidentalFourierTransform has thirty hats.
 
:O
I think @MikeMiller won first place last year.
 
user223506
1:43 AM
@DanielSank holy hell!
 
user223506
excellent, the edit has been approved!
 
2:03 AM
Anyone know where i can find solutions to Hill's intro to statisical thermodynamics?
 
user223506
 
user223506
if it is still deemed to be too broad - I have an idea for the OP that could even refine it further
 
@Doc It should be placed in the review queue automatically.
58
A: Lots of questions in the reopen queue

Shog9We just rolled out a change to how questions are automatically added to the reopen queue. Previously, if the author edited a closed post within 5 days of it being closed, that would trigger it to be added to the queue. This was a great way to get additional views for questions that might've been ...

 
3:28 AM
@DanielSank, wow, almost forgot about that...I'll double-check with my mom though I think I can get her to say yes =D
@DanielSank, ack, must get more hats!
 
user223506
@DavidZ excellent - I'll await the decision of my peers
 
3:59 AM
i am so confused - quantumexperience.ng.bluemix.net/qstage/#/… - the first thing can't equal a toffoli gate because i tried it and the math doesn't work out.
also, i don't understand the difference between the second and the first way to simulate a toffoli gate listed on that site.
 
Yo @heather, someone I work with made a quantum algorithm simulator.
 
that might be a lot easier =)
oh, darn, soon as I have a question, i have to go =P
why is this how it works? =)
 
4:14 AM
@DanielSank I saw that you had for some time a room related to linear algebra. At math.SE there is a room called Linear & Abstract Algebra - I just thought it is worth mentioning if you are interested in it. (Or anybody else.)
I have to admit that it is mostly inactive. But at the very least, if you create a new room on linear algebra or unfreeze the old one and you want to advertise it somewhere, LA room at math.SE sounds like a reasonable possibility.
And only now I have noticed that you have already left the rooms since you posted the message above. Never mind, you'll probably read this kater,
 
4:40 AM
@MartinSleziak thanks!
 
You're welcome. I am not sure whether it is actually useful information, but mentioning the existence of that room probably does not do any harm.
 
user228700
5:17 AM
@DanielSank It's beautiful :-)
 
This makes me smile
Hummingbirds sense motion equally in all directions, and enable them to have precision in their flight and carry out various activities form courtships to sipping nector hovering
Availability vs ability
Would be really cool to factor that into new zombie apocalypse games
 
5:49 AM
Research on QGP continues to excite as we approach a possible critical point at nuclear matter transitions
 
What will be limit_t→0 t.In(t)?
 
Pluto really has a lot of interesting icy terrain
I actually would argue that even for that errorenous measurement, all 3 troughs in the graph showed an upward trend, although statisticians will then argue that 3 troughs are not enough to establish a trend
That's good. From the graph (I actually read the % only as circles ar misleading), it seemed as expected, an improvement in the power grid will brought the greatest increase. However, carbon tax also boost growth the 2nd greatest
On a more political side, however, you will need something more profit sounding (recall that trump is a businessman) than that in order to coaxe the trump government to do stuff along that direction

Another interesting thing also brought up by this topic: Is it possible to get a worldview to do certain things the contrary to its ideals but it still strongly believing that contrary action is actually in alignment to their worldviews?
Mind your words
 
user228700
6:22 AM
Hello, everyone :-)
 
Consumer behaviour and marketing. It's more complicated than we thought: e.g. People who own a product of a brand is more likely to search that brand for maintanence queries and other info, even when they are not shopping
 
Morning :-)
 
user228700
Whoa whoa, what is up with the starboard?!
 
No idea
There are only 3 people here and post owners cannot star their own messages
 
Wasn't me!
 
6:26 AM
But anyway, for whoever that star it, note that my commentary follow after the sciencedaily link, thus you don't need to star the sam thing twice
 
user228700
:-| What just happened?
 
rob probably help unstar them
 
user228700
Anyhoo, I decided to well and truly abandon the chapter about semiconductors and move on to more important tasks such as finishing the chapter about Chemical Bonding. I'm reading about backbonding/synergic bonds now and this is what my textbook says:
 
user228700
> "The extent of backbonding decreases if the atom having vacant orbitals is also having some non-bonding electron pairs on it. So, among the atoms of the third period, the extent of backbonding follows this order: Si>P>S>Cl"
 
user228700
Also:
 
user228700
6:30 AM
> "The extent of $p\pi - p\pi$ overlapping $\propto$ 1/(Lewis acid character)"
 
@Secret I was starring them to check whether a single star is sufficient to replace messages with multiple stars. I removed them. Hope you didn't mind. I liked your message though.
 
I see
 
Can moderators see who starred a comment ?
 
Big data helped illuminate how our consuming behaviour affect habitat elsewhere
 
user228700
The more acidic (Lewis concept) that something is, the more electron-deficient it is, which only means that the extent of $p\pi-p\pi$ bonds that it participates in is actually greater, no?
 
user228700
6:36 AM
Also, what is up with the first point that I quoted?
 
@Kaumudi.H Yes. However, back bonding requires empty orbitals.
 
user228700
@MathJack Yes, so..?
 
@Kaumudi.H Well, what is your question actually ?
4 mins ago, by Kaumudi. H
The more acidic (Lewis concept) that something is, the more electron-deficient it is, which only means that the extent of $p\pi-p\pi$ bonds that it participates in is actually greater, no?
 
user228700
My question is about why this makes sense:
 
user228700
9 mins ago, by Kaumudi. H
> "The extent of $p\pi - p\pi$ overlapping $\propto$ 1/(Lewis acid character)"
 
user228700
6:41 AM
What u quoted was me trying to argue against what my textbook is saying.
 
Lewis acids are electron deficient and to overcome the deficiency the p pi-p pi overlap has to be increased.
Greater overlap means better sharing of the electron clouds
@Kaumudi.H
 
user228700
I don't know if u understand what I'm really asking. My textbook is saying that the extent of overlapping depends on the Lewis acid character.
 
@Kaumudi.H Well it does. Your textbook is correct. I explained why in my previous message.
 
user228700
So my textbook is saying that the more electron deficient a species is, the lesser it overlaps which still doesn't make sense to me.
 
user228700
@MathJack You're saying that it has to be increased. What my textbook is saying is that if it has a greater Lewis acid character, then the extent of $p\pi-p\pi$ overlapping decreases. It simply does. And I don't get that. Dyou understand what I'm asking..?
 
user228700
6:48 AM
Ah, I see how my textbook makes sense.
 
user228700
It's just that I've been thinking of the Lewis acid character as the "independent variable" in this relation, so to speak.
 
user228700
What my textbook is really saying is that the Lewis acid character decreases when the extent of the overlap increases because of course, it's less electron-deficient than before.
 
user228700
I still don't understand what it's trying to say in the first point I quoted though:
 
user228700
21 mins ago, by Kaumudi. H
> "The extent of backbonding decreases if the atom having vacant orbitals is also having some non-bonding electron pairs on it. So, among the atoms of the third period, the extent of backbonding follows this order: Si>P>S>Cl"
 
user228700
I guess I don't fully understand the mechanism just yet. I can see why this would make sense...but not completely.
 
user228700
6:53 AM
Can anybody point me to a good source to learn about the mechanism? I've been searching and failing for the past 1.5 hours...almost.
 
user228700
@JohnR: Nice hat, BTW :-)
 
Probably my last hat of the season
 
user228700
:-( When are they taking them back?
 
A bit dull though. I'm not sure grey and black suit me :-)
@Kaumudi.H any day now. I forget the precise date.
 
user228700
Damn :-/
 
user228700
6:59 AM
Friggin' back bonding. Dyou anything about it?
 
I'm afraid I don't know anything about gluing backs together
 
user228700
Lol, if only it were that simple.
 
Are there anymore context to the statements in the textbook, it feels like their descriptions does not involve a metal as one of the participants in the pi backbonding?
 
user228700
I'll show you all the context there is:
 
user228700
 
user228700
7:05 AM
@Secret: Dyou know about the mechanism of backbonding, by any chance?
 
I knew them well for metals. Here these took place in the main group elements. I do have notes about that but I need to dig them up again
 
user228700
Ohh. Um, dyou know them now? Like, do u a) Have time and b) Maybe want to help me to understand it..?
 
I have just dug the slides, it seems to agree what your textbook said, however I need to figure out that 1/lewis acid character which in my notes is related to less stablisation by pi backbonding. Give me a sec
Ok first off:
42 mins ago, by Kaumudi. H
> "The extent of $p\pi - p\pi$ overlapping $\propto$ 1/(Lewis acid character)"
 
user228700
Oh, crap, hang on.
 
user228700
Yes, your slide makes sense because firstly, the larger the donor atoms are, the lesser the extent to which they will donate electrons to the ligand.
 
user228700
7:15 AM
Since Iodine is far down the group, it's much larger than fluorine, because of which its extent of overlap with Boron is much less than fluorine.
 
user228700
And then of course, we know that Lewis acids are acidic because they need electrons. BUT the more overlap there is, the less they need electrons.
 
exactly
 
user228700
So yeah, that point makes sense.
 
user228700
This one doesn't:
 
Now however, my slides back then seemed to have not explained the period trend. That I need to lookup
 
user228700
7:17 AM
26 mins ago, by Kaumudi. H
21 mins ago, by Kaumudi. H
> "The extent of backbonding decreases if the atom having vacant orbitals is also having some non-bonding electron pairs on it. So, among the atoms of the third period, the extent of backbonding follows this order: Si>P>S>Cl"
 
user228700
@Secret Oh, okay...
 
user228700
I have a feeling that this trend has a lot to do with the mechanism of backbonding.
 
user228700
I'm thinking maybe having lone-pair of electrons on the ligand will cause repulsion..?
 
user228700
Nope nope, that was rubbish.
 
I suspect analogous to the metal case, it might be an issue of an increase in mismatch of orbital energies. Orbitals in the same period have roughly the same size except the electron cloud in the whole atom decreases across the period as the effective nuclear charge increases thus pulling the cloud closer
So it might also be an issue of extent of overlap. Let me see if I can find anything else about it
 
user228700
7:20 AM
Huh.
 
user228700
Haha, reverse engineering always works. I mean, I can just as well use the same size argument to explain this given that the order is actually reverse than what I had thought it to be. You see, since the charge is less... diffuse in Si than in Cl, there is a higher extent of overlapping, because the repulsion decreases.
 
user228700
Does that make sense?
 
user228700
7:36 AM
@Secret: Hello..?
 
Still looking up polar pi bonds If the charge is less diffuse, then we should expect less overlap since the charge density is closer to the atom to allow good overlap
 
user228700
:-| Huh.
 
STILL looking I think one possibility is that because the effective nuclear charge of the atom is higher across the period, the electron cloud of Cl is tighter than Si, thus Cl should have a poorer orbital overlap in general compared to Si
But I don't think that is a sensible explanation
 
user228700
That actually does make some sense...
 
user228700
Hmm, @Secret: Should I maybe ask a question over that the CSE main site?
 
7:43 AM
perhaps it's a good idea (I am kinda considering that as I start to lookup CSE for simialr questions now). The fact that it does not came across in my uni lecture note and there is almost nothing about it in google search suggest it is likely a rarely touched upon topic, which if true, then your textbook might be actually good on that point
 
user228700
'Cause forget the trend, it says "The extent of backbonding decreases if the atom containing the vacant orbital contains non-bonding lone pairs".
 
user228700
When I first read this I thought "Of course, won't those lone pairs repel the incoming ones?"
 
user228700
And that makes sense, I guess..? @Sec
 
user228700
But yeah, the trend doesn't make any sense (to me).
 
nonbonding lone pairs will indeed occupy MOs of some interesting sp like shapes, thus adding weight to the repulsion explanation. The closest thing in my uni lecture note is the group trend but not the period trend, which it said nothign about it
 
user228700
7:47 AM
U guys take notes on a computer?
 
(And if I had not ask my professor about it, there won't even be those two red columsn you saw here)
These slides are actually slides I made back to prepare for my uni exams. Only the middle and right bit are from my professor's lecture notes, for this slide
 
user228700
U make slides to revise stuff..?
 
They have been cross checked by my peers and even some of my professor and pretty much condense everything I learnt in the syllabus
yes, because I am visual person. I rather see a lot of pictures than a wall of text
 
user228700
@Secret Oh, cool.
 
The reason I can answer some of my EM question later in PSE is because of these slides
 
user228700
7:50 AM
I'm a little like that too...I take all my notes on paper, in color; black, pink, blue, orange, green, purple, red...
 
Most biology students also like to make notes with a lot of colors
 
user228700
Oh. I'm not a bio student tho :-P
 
I have been one for 2 years (year 1 and year 3)
 
user228700
Oh, I see.
 
(because I like microbiology)
 
user228700
7:52 AM
Anyhoo, thanks very much for your help! :-D
 
user228700
@Secret And also zero. U're obsessed with 0 :-P
 
I am obssessed with the nothing, (don't worry, my non frustrated personality have no interest in nihilism. In fact, my usual personality has a philosophy that it does not matter what the world think about you, as long you are happy)
(but why I am obssessed with the nothing is because it is a type of something, a something that few people understood and know how to use. The concept of void is especially powerful in installation arts, for example)
 
user228700
Well, in my case, thinking about the world from a nihilistic viewpoint for far too long gives me a terrible headache and steals away some of my will to live for a little while. But there's always useless blabber everywhere to remind me to take it all a little less seriously :-)
 
Indeed. For me the world is agnostic. You are free to sit on the fence and listen to what all known worldviews are thnking
 
user228700
U keep changing what the world is to you :-P
 
7:57 AM
like a wavefunction, nothing is certain
 
user228700
:-) Indeed.
 
user228700
@JohnR: I wasn't able to stop listening to Lazarus after our brief discussion last night. I left the room at 11:15 PM but only forced myself to switch off my phone at around 12:50 AM.
 
I'm not sure that's great for your sleeping patterns :-)
 
user228700
Certainly not :-) That song is almost... bewitching.
 
I do like Deadwind, though if I had to choose a favourite PT track it would probably be Radioactive Toy.
 
user228700
8:08 AM
To be completely honest, I haven't listened to many songs by PT. Just their more famous ones. Lazarus, Trains, and Arriving somewhere but not here.
 
user228700
I may have listened to others but I don't remember, which means that I didn't obsess :-P
 
I'm surprised you've even heard of Porcupine Tree. They are well known amongst us prog rock nerds, but I'd guess the average member of the UK public has never heard of them. That makes it all the stranger that someone from India is a fan.
 
user228700
:-) It was one of my friends who introduced them to me. Say, given that I absolutely love *Lazarus", what are some other songs by them that I'm likely to enjoy..?
 
user228700
Introduced me to them or introduced them to me? :-|
 
user228700
The latter, yes?
 
8:13 AM
(NB Please do not post the Si>P>S>Cl question on CSE, cause I am posting it now)
 
user228700
@Secret Sure :-) Thanks.
 
I'd probably use introduced me to them because you were the one who was acted on i.e. your friend spoke to you. So you are the object rather than the subject. But it's a fine distinction and doesn't really matter.
Porcupine Tree have changed a lot over their career. Their early albums are a bit strange. Deadwing is their most accessible album, so if you like it I suspect that's the one you would like most.
If it's not a silly question, have you heard Dark Side of the Moon?
You might also be interested in The Pineapple Thief
 
user223506
hello all and sundry!
 
user223506
hello @JohnRennie
 
user223506
I am glad I took your suggestion a little while ago and joined
 
8:25 AM
0
Q: Trends in pi backbonding for main group elements across a period

SecretRecently, I have been re-reading some undergraduate notes and found that there's a period trend in pi backbonding of main group elements (i.e. no transition metals involved) but no explanation were given other than it correlates with the increase in number of nonbonding pairs (lone pairs?): $\pi...

 
@Doc good, I'm glad it's been fun. The PSE is a truly astonishing resource. When I was a teenage physics nerd back in the 1970s it was inconceivable that I could speak to real live physicists and get answers from them. How times have changed.
 
user223506
@JohnRennie absolutely, even 15-20 years ago
 
user228700
@JohnRennie Ah, OK, that makes sense.
 
user228700
@JohnRennie I sort of have...
 
@Doc whenever I write an answer I always bear in mind that the 2017 version of me is probably out there somewhere and desperate to learn about cool physics. God help them! :-)
@Kaumudi.H You should have a good listen to Dark Side of the Moon and Wish You Were Here. Deadwing is PT's most Pink Floyd like album.
 
user228700
8:35 AM
@JohnRennie Oh, cool, I'll check it out. Thanks! :-D
 
user223506
@JohnRennie if there is a 2017 version of me - heaven help the world!
 
Actually, about 0, yesterday I and akiva have been reanalysing a famous paper in the topic of division by zero (Wheel theory) that was published by Calstr:om in 2009 and after spending quite a bit of hours working out the rules, we then discuss about one of the uses the author claimed that his Wheels can contribute to algebraic geometry
 
user228700
@JohnRennie Oh, OK, will do. Thanks very much :-)
 
Background: In order to understand wheels, think of an onion
At the centre of the onion are the numbers we are familiar of: fractions, reals and complex numbers
Negative numbers exists for them all
Moving 1 layer out of the onion, you lose the negative numbers, but you still have division such that you can get one as a result
Now moving 1 layer up, you now lose division, but you still have every number multiply to zero give zero and equations where if ax=ay, then x must = y
Moving another layer up, you lose this x=y property and only have numbers that 0x=0
 
user223506
@Secret an onion...like Shrek?
 
8:47 AM
well it depends, you cannot really smell a wheel anyway
 
user228700
@JohnR: I generally am not a fan of any proper song that's over 6 minutes :-P That sounds ludicrous, but it's true.
 
And finally, when you reach the crust of the onion, you have weirdoes like 0/x, x/0, 0/0, x-x and x/x
 
user223506
@Secret you haven't seen what my brother drove through...
 
@Doc I was thinking along similar lines :-)
 
I see
 
user223506
8:48 AM
@JohnRennie lol
 
There are a lot of cows here in Cheshire :-)
 
user223506
@JohnRennie do they have ow-culators?
 
(cont. frm previous unbroken message) And this whole onion, is wheels
 
Onions? Wheels? These chemicals you've been working with - have you considered not sniffing them? :-)
@Kaumudi.H how much Genesis have you heard?
 
user223506
Onion Wheels - could be the next snack for physicists!
 
8:51 AM
to be frank, ethers smell like burnt oil
 
user228700
@JohnRennie Genesis?
 
and a sense of drowning
 
user223506
@Secret sounds like my cologne
 
user223506
@JohnRennie good song!
 
user228700
8:53 AM
Song? Isn't that a full album?
 
user228700
Yowza, some of those songs are very long!
 
user223506
yes, that is what I meant - too mnay ethers on my mind
 
@Kaumudi.H This is also good and has shorter songs:
Actually now i check they aren't that much shorter ...
 
user228700
@JohnRennie Oh, okay, thanks. Like I said, I am open for suggestions after 21st of May. Till then, I don't have much time to properly explore.
 
Your 6 minute limit rules out much of my favourite music.
 
user228700
8:58 AM
@JohnRennie Damn :-/ If it's any longer than that I usually just sort of get bored. I mean, can't u just split it into two songs? Like, C'mon, where are u going with this?!
 
user223506
i have to say that as a child of the 80's and 90's - I still love Metallica
 
@Kaumudi.H Most long tracks have an internal structure e.g. the ternary form or some more complex sructure. So they aren't really a single monolithic track.
 

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