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24-Ruby IV

## Changes in the International System of Units and Mathcad

The committee to collect data in the field of science and technology (www.CODATA.org) produces every four years a list with redefined values of several physical constants. In the 2010 list, for example, you can find redefined values of constants, including the uncertainty parameters. So you can find the value of the fine structure constant, which is used in atomic physics, with reduced uncertainty. Furthermore, there is the specified Planck constant, which relates the energy of electromagnetic radiation to its frequency. These changes also affected the Avogadro number, showing the number of particles in one mole of a substance, and the Boltzmann constant, the binding energy and temperature. Redefined values of the constants, especially of the Avogadro constant and the Boltzmann constant were seen by physicists as a signal to update the international system of units (SI), which will be discussed in 2014. This will primarily affect the five units - amperes, moles, kilogram, kelvin and pascal. Proposals to refine the values of the majority of them have good prospects.

The stumbling block of the discussion was the reference value of one kilogram, because the reference value is likely to change and therefore regularly causes debates among the scientific community. Some experts propose to define kilogram, based on the value of the Planck constant. In addition, it is proposed to give a new name for the kilogram. Due to the fact that a kilogram is the only SI base unit having a multiplier - kilo. So there will be competition for the best name for the updated basic unit of mass, as noted above, it will be tied to the Planck constant, rather than the platinum-ridium standard kilogram stored in the Paris Chamber of Weights and Measures. It is most likely that there will win a title referring to “Stein” and derived units. “Stein”, rather, “ein Stein” is the German word for a stone - an object with mass. On the other hand, it is a part (a root)of the name of the genius physicist Einstein, who was not included for various reasons in the "pantheon" of units - volts, ampere, watt, kelvin (celsius, rankine, fahrenheit), newton, joule, pascal (see below), ohm, farad, weber, tesla, henry, siemens, becquerel, gray, sievert. Replacing kilograms with stein will correct this injustice.

Another significant change will affect a pressure unit - pascal. The dispute here is that this unit is too small, and it is almost always necessary to use multipliers like kilo, mega and giga. Because of this, you can recognize in science and technology still a strong use of alternative units of pressure, for example, bars or torr, etc. This diversity also often leads to errors in calculations. There is a plan to redefine pascal - the basic unit of pressure into the "new pascal" equivalent 100,000 old pascal. This will set a transition period in which it will be possible to use both the old and new units of pressure, and then the old pascal will be withdrawn from step by step form calculations.

1 ACCEPTED SOLUTION

Accepted Solutions
10-Marble
(To:StuartBruff)

This is a known issue. The following constants will be updated in Mathcad Prime 8:

- Planck constant

- Boltzmann constant

- Reduced Plank`s constant
- Atomic mass unit
- Molar gas constant
- Fine structure constant
- Elementary charge
- Stefan-Boltzmann constant
- Magnetic flux quantum
- Rydberg constant

If you see any other predefined value that needs to be updated and is not in this list - please let us know.

14 REPLIES 14
23-Emerald II
(To:ValeryOchkov)

Following the update to the SI in 2019, Avogadro's constant changed to 6.022 140 76×1023 mol-1.

,/sup>

Mathcad Prime 7 is still showing the old value of NA = 6.022 141 79 x 1023 mol-1.

Could a PTC rep please take note for the next update?

Stuart

24-Ruby IV
(To:StuartBruff)

Open, please, and transate into English
Degrees.pdf (mpei.ac.ru)

Stuart! Can you send me the corrected translation
And more

Pseudo.pdf (mpei.ac.ru)

23-Emerald II
(To:ValeryOchkov)

@ValeryOchkov wrote:

Open, please, and transate into English
Degrees.pdf (mpei.ac.ru)

Stuart! Can you send me the corrected translation
And more

Pseudo.pdf (mpei.ac.ru)

Eek!  😱  Мой русский не так хорош!

And, having had a quick look, neither is Mr Google's Finest Translator's best effort much better.

Но я попытаюсь.

Stuart

... I don't think my "100 Words in Russian" book is going to get me very far on this task.

24-Ruby IV
(To:StuartBruff)

Спасибо, Стюарт!

Я буду ждать перевода.

10-Marble
(To:ValeryOchkov)

Alcohol by volume units are not called "degrees" in English, so at least one paragraph seems to be not translatable... 🙂

23-Emerald II
(To:MSheykman)

@MSheykman wrote:

Alcohol by volume units are not called "degrees" in English, so at least one paragraph seems to be not translatable... 🙂

("degrees proof" is an archaic measure, used in the UK Sikes system until 1980, for measuring alcohol strength (eg, https://www.diffordsguide.com/encyclopedia/192/bws/overproof-and-navy-strength))

Stuart

24-Ruby IV
(To:StuartBruff)

Мы говорим - этот человек под градусом. Это означает, что он пьяный.

23-Emerald II
(To:ValeryOchkov)

@ValeryOchkov wrote:

Мы говорим - этот человек под градусом. Это означает, что он пьяный.

Его кровь на сто градусов / процентов проба (proof?).

(His blood is 100 percent/degrees proof)

24-Ruby IV
(To:StuartBruff)

- ???

- Был под градусом!

23-Emerald II
(To:ValeryOchkov)

@ValeryOchkov wrote:

- ???

- Был под градусом!

хорошо.

собака: "выпивши был ...

В противном случае у меня не хватило бы смелости пригласить ее на свидание."

Stuart

(I really must get an English/Russian keyboard.  I can never remember where the punctuation keys are when I switch to Russian, plus I use both Macs and Windows PCs, so ё's position is always a bit of a mystery)

17-Peridot
(To:StuartBruff)

Hi Stuart,

I passed along that the Avogadro constant is different to what Mathcad Prime 7 has predefined it as to our product manager.

Edit: Even better, he forwarded it to R&D. Thank you for pointing this out!

Edit 2: It, and the other constants if necessary, will be updated with the release of Mathcad Prime 8.

I manage the Creo and PTC Mathcad YouTube channels for PTC, as well as all PTC Mathcad marketing in general.
23-Emerald III
(To:DJNewman)

"It, and the other constants if necessary, will be updated with the release of Mathcad Prime 8"

I bet they need an update, since the entire system of units was changed. You can read all about it in the SI brochure:

The very important change involves that now, next to the velocity of light, 6 more fundamental natural constants have been given a defined value (without uncertainty), and the basic units (m, s, kg, etc) are now all derived from these constants. See in particular section 2.2 of the brochure.

While you are at it. also make sure that units in Prime are by default set in the correct font (upright, Roman style, not Italic), see section 2.3.1 of the brochure, next to table 2; or for full information see section 5.

Success!
Luc

10-Marble
(To:StuartBruff)

This is a known issue. The following constants will be updated in Mathcad Prime 8:

- Planck constant

- Boltzmann constant

- Reduced Plank`s constant
- Atomic mass unit
- Molar gas constant
- Fine structure constant
- Elementary charge
- Stefan-Boltzmann constant
- Magnetic flux quantum
- Rydberg constant

If you see any other predefined value that needs to be updated and is not in this list - please let us know.

24-Ruby IV
(To:MSheykman)

We need the Gravity constant!

We need not the molar gas constant. We must use it only by temperature converting from J/mole to K, C, F, R.

See one calculation

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