User talk:Double sharp

"Data not decisive" on most stable isotopes

By the time I write this, Tc, Sg, Hs have "data not decisive" footnote beside their mass numbers. However, I found that Lr, Lv, Bh, Ts (and possibly Bk) are all less decisive than Hs. I'm not sure what should I do, either removing the footnote in Hs, or add the footnote to these 4(+1?) elements.

Also, do this footnote need to extend to elements beyond Hs, like all elements with overlapping 2σ confidence intervals? (This adds Mc and Mt to the list.)

Thanks! Nucleus hydro elemon (talk) 14:40, 31 July 2024 (UTC)

@Nucleus hydro elemon: I think 2σ is a good threshold. So yes, feel free to add the footnotes, perhaps with an explanation. :) Double sharp (talk) 14:57, 31 July 2024 (UTC)

Just realized a problem: when we cite NUBASE2020, do we use the symmetrized half-life (using ²⁸⁶Nh as example, 12±5 s) or the original unsymmetrized half-life (9.5+6.3
−2.7 s)?

Nh is a borderline case, if we use the unsymmetrized 9.5+6.3
−2.7 s, then the 2σ confidence interval of ²⁸⁶Nh doesn't overlap with ²⁸⁵Nh; but if 12±5 s was used instead, they crash. Nucleus hydro elemon (talk) 16:01, 31 July 2024 (UTC)

@Nucleus hydro elemon: I would prefer to use the original unsymmetrised half-life. Double sharp (talk) 05:46, 1 August 2024 (UTC)

Added for Lr, but I have struggle on other elements (and Hs too) that don't overlap at 1σ, but overlap at 2σ. I'm not sure if the following:

If the 1σ confidence interval is 9.5+6.3
−2.7, then the 2σ confidence interval should be 9.5+12.6
−5.4

is still in the range of WP:CALC. If it doesn't, I will have no idea on how to write these footnotes. Nucleus hydro elemon (talk) 07:36, 2 August 2024 (UTC)

Invitation to join the Fifteen Year Society

Dear Double sharp,

I'd like to extend a cordial invitation to you to join the Fifteen Year Society, an informal group for editors who've been participating in the Wikipedia project for fifteen years or more. ​

Best regards, The Herald (Benison) (talk) 02:48, 7 August 2024 (UTC)

— The Herald (Benison) (talk) 02:48, 7 August 2024 (UTC)

@The Herald: Thank you! :D Double sharp (talk) 03:20, 7 August 2024 (UTC)

Nomination of Crossed square cupola for deletion

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Production of transuranium nuclides

I was wondering that, which of ²⁵⁰Cm, ²⁵⁴Cf, ^252-255Es can be produced in quantity at least of micrograms? I think ^253,254,255Es are available because they can be formed when ²⁵²Cf absorbs neutron; for the others, I don't think so. 14.52.231.91 (talk) 01:01, 16 August 2024 (UTC)

Seems to be just Es-253 and Es-254. Es-255 is shorter-lived...but I'm not sure it has ever been done even for Es-253 and Es-254. Double sharp (talk) 04:38, 16 August 2024 (UTC)

Thanks! At least we can have confidence with ²⁵³Es, as Wikipedia states explicitly that "Einsteinium is the element with the highest atomic number which has been observed in macroscopic quantities in its pure form as einsteinium-253". 14.52.231.91 (talk) 00:46, 19 August 2024 (UTC)

I think ²⁵⁴Es is also OK because it has been used in the nucleosynthesis of ununennium. As for ²⁵⁵Es, it has even longer half-life than ²⁵³Es... 14.52.231.91 (talk) 00:55, 19 August 2024 (UTC)

Back in that 1985 attempt, less than a microgram of ²⁵⁴Es was actually used – which was probably one of the reasons nobody saw anything. (Another is also probably that back then, the cross-section limit wasn't enough to see anything from ²⁴⁸Cm+⁴⁸Ca either.)

I actually have a significant worry that 119 will take a while to come after 120 (which has taken a long time already). That's because with the cross-sections likely to be the way they are, a ²⁴⁹Bk target might very well have significantly decayed by the time the first successful fusion occurs. And using ²⁴⁸Cm+⁵¹V gets the penalty of having the odd proton in the projectile instead of the target, while ²⁴³Am+⁵⁴Cr will likely have a smaller cross-section than ²⁴⁹Bk+⁵⁰Ti and leads to a more neutron-poor ER. But oh well, we've all waited fourteen years and counting for 120 in the first place. :) Double sharp (talk) 04:49, 19 August 2024 (UTC)

Either 119 or 120 coming first would be OK to me - we would be closer to finally finishing the periodic table up to n + l = 8 :) 14.52.231.91 (talk) 02:27, 20 August 2024 (UTC)

Haha, yes. The Janet table is great! But what I really want is to see the g-block. Hopefully, after that people will finally universally get group 3 correct (after Y comes Lu and Lr, certainly not asterisks or La-Ac). :) Double sharp (talk) 02:55, 20 August 2024 (UTC)

G-block would be a lot harder, and it's even worse that the first element with a 5g electron comes much later... 14.52.231.91 (talk) 07:00, 20 August 2024 (UTC)

Yeah, probably each change of projectile will mean things get one or two orders of magnitude worse. :( Probably already E121 has 5g low enough to participate in chemistry at least. But doing actual chemistry with the expected half-lives and low rate of production seems very far off. Still nobody has done Mt. (Okay, to some extent it's partly that Mt chemistry will probably be like Ir, making it hard to get into solution and also hard to find volatile compounds without using F₂.) Double sharp (talk) 10:00, 20 August 2024 (UTC)

What I also find curious is that only the lightest isotopes of Mt and Rg have been directly synthesized and no new hot fusion reactions have been attempted for those elements. ^Complex/_Rational 13:55, 20 August 2024 (UTC)

@ComplexRational: Considering the cross-section trend, wouldn't it be easier to fill them in from Mc, just like it's easier to produce Cn as an overshoot product from Fl? Though I have been hungering for ²³¹Pa+⁴⁸Ca for a while, especially now that ²³²Th+⁴⁸Ca has been successful. (And can someone please do ²⁴¹Am+⁴⁸Ca already? :D) Double sharp (talk) 14:57, 20 August 2024 (UTC)

Sadly it seems like no one cares about ²³¹Pa + ⁴⁸Ca, even the most recent reference about it was from 1981. :(

On the other hand, ²⁴¹Am + ⁴⁸Ca got a recent reference. In there, reactions involving ²⁴¹Am was even considered to create elements 119~122. :) Nucleus hydro elemon (talk) 16:01, 20 August 2024 (UTC)

@Nucleus hydro elemon: T_T Thanks for the papers! (Though I'd want to stick to ²⁴³Am for going beyond 118, at least at first. I wonder how close we are to the proton drip line in this region...) Double sharp (talk) 16:11, 20 August 2024 (UTC)

For cross sections, targeting Mc and observing its decay chains would certainly be more feasible based on experimental data. However, indirect synthesis is said not to be optimal for investigation of chemical properties.

And re below, the KTUY chart that I uploaded some time ago suggests that we are already very near the drip line for odd-Z superheavy elements, but the partial half-lives for alpha/SF are expected to be longer than those for proton emission, so I'm not sure if we'd even know. ^Complex/_Rational 18:50, 20 August 2024 (UTC)

@ComplexRational: Sure, though Cn and Nh were both investigated through indirect synthesis. So at least it's a possible option when the cross-section is likely to be worse for the lighter elements. :) Thanks for the answer on the drip line! Double sharp (talk) 02:55, 21 August 2024 (UTC)

@ComplexRational: Double sharp (talk) 10:09, 18 August 2024 (UTC)

Leep year setting for octal and nonary civilizations

I've come up with the calendar for civilizations living on Earth that use octal or nonary. I suppose that a week is still 7 days, because the number seems to be base-independent. I will use our seconds for comparison, even though a non-decimal civilization would have defined a second to be something else than 1/86400 of a day.

For people using nonary: Set a leap year in every 4₉ years, then eliminate one every 130₉ years, and add one back every 800₉ years.

This will make 184₉ leap years out of every 800₉ years, so a year would be 31638.3₉ seconds longer than a multiple of a day. The tropical year is 31631₉ seconds longer than that, so the difference is 7.3₉ seconds. A period of 800₉ years contains exactly 51337₉ weeks.

For people using octal, there are two choices. The more natural one would be to set a leap year in every 4₈ years, then eliminate one every 200₈ years. But we have to wait for 1600₈ years until the weekdays repeat themselves. Another choice with a period of 1600₈ years is to set a leap year in every 4₈ years, eliminate one every 160₈ years, then add one back every 1600₈ years.

In either case there will be 331₈ leap years out of every 1600₈ years, so a year would be 50675₈ seconds longer than a multiple of a day, which is only one second short compared to the tropical year!

In conclusion, the octal calendar wins by accuracy but the nonary one wins by a shorter period of weekdays. Still, it's amazing that the orbital period of the Earth can give a calendar in periods of a multiple of centuries which is accurate enough, for people using either decimal, octal or nonary :) 14.52.231.91 (talk) 06:51, 22 August 2024 (UTC)

By the way, my edit triggered filter 1321 when I tried to post all the paragraphs as a whole. But when I performed the edits in posting just some paragraphs at a time, the edits were OK. 14.52.231.91 (talk) 06:55, 22 August 2024 (UTC)

It seems that the edits were limited to 1280 characters. (Of course, since I did not mean to do any vandalism, my test stops here.) 14.52.231.91 (talk) 07:03, 22 August 2024 (UTC)

Very cool! The edit filter may not have appreciated these calendars, but I do! :) Double sharp (talk) 07:56, 22 August 2024 (UTC)