The Short Questions Thread (4)

In the book Introduction to magnetism and magnetic materials by David Jiles page 34 it gives a table
shown below. The figures of x and ur do not seem to make sense (according to the formula below the
table).
Am I missing something or is the table wrong?

Yob

Maths leg up required (get out the spoons)

Can anyone tell me how to get from line 1 to line 2 in the pictures attached.
Thanks,
Yob

This case is now closed

B = UoH + UoM

UoM = B - UoH

Divide both sides by H

Uo X = (B/H) - Uo [ X = M/H = susceptance = Ur -1 BTW]

Uo(Ur - 1) = (B/H) - Uo

UoUr - Uo = (B/H) - Uo

B = UoUrH

B = U H




and the second one

B = Uo(H + M)

B = Uo(Ni/L + M) H = Ni/L

B = UoUr(HI/L) FROM RESULT ABOVE

B = U Ni/L

Ni = BL/U

Cheers,
Yob

Quote: Originally posted by yobbo II

Hello, Not too sure if this is appropriate here .. but I am trying to sort a spread sheet on a certain columb. The columb in questing contains a very large number, 15 digits. I do not want to sort the sheet on the actual value of this number but rather on the value of the last three digits of the number. In other words I want to sort the sheet using the last three digits of the columb containing the very large number. Cannot figure it out. Using a fairly old version of excell. If I could AND the number with 0000000000000111 (12 zeroes and three ones) I would strip away the digits I do not want (create a new columb and sort on the new columb but I am unable to do this AND. Cheers, Yob

Thanks alot B(a)P,

That was exactly what I needed.
There is still a small problem but only a small one. I need to do the sorting very seldom.

It may be just a software glitch from using old Works.

When I paste in my info. the column (col A) with the large number gets pasted in in scientific notation (the number in notepad before pasting is just a simple 15 digit number).
I convert the column (A) to text and the number stayes as scientific notation.
The only way to 'convert' back to a 15 digit number is to double click on the number.
Sounds a bit weird.
Any suggestions?
The picture explaines things a bit better.

Thanks alot,
Yob

@solo appologies for talking over you!



[Edited on 17-10-2023 by yobbo II]

Quote: Originally posted by yobbo II

Thanks alot B(a)P, When I paste in my info. the column (col A) with the large number gets pasted in in scientific notation (the number in notepad before pasting is just a simple 15 digit number). I convert the column (A) to text and the number stayes as scientific notation. The only way to 'convert' back to a 15 digit number is to double click on the number. Sounds a bit weird. Any suggestions? [Edited on 17-10-2023 by yobbo II]

I cannot get the =MOD(Ax, 1xxx) to work as the sheet gives an error. This must be a bug?
Both B2 and B3 are formatted as numbers. Setting greater number of decimal places does not help (It should not matter anyways)
See the picture

I got the sheet to work with the following:

I used the =string(Ax,0) (same as =text(xxx) I guess) to convert to general format this gets rid of the scientific notation
followed by =right(Ax, 4) to give me the four digits to sort on.

Thanks for you time

...help finding the correct name for compound ...i tried 2-ethyltert butylamine-1-phenylbenzoate ...but no results....its a steroid precursor .....solo



[Edited on 4-11-2023 by solo]

Quote: Originally posted by FableP

I'm planning a HiPEP project. It looks like BaNO3 might be the way to go.

Why does the nitrate ion exist?

Iron (II) sulfate

Quote: Originally posted by DraconicAcid

The brown crud is from oxidation of iron(II) to iron(III), which happily precipitates as various forms of rust. You might try adding excess sulphuric acid to prevent this.

Thorium nitrate

...trying to find the name the 4-amine of 2-tertbutylamine-1-pheny ethanol,...can;t seem to get the right name so i can get some specs and physical properties....could use some help!!...solo

note:

its something like this..

4-amino-N-(tert-butyl)benzamide , but its an amine









[Edited on 2-3-2024 by solo]

Quote: Originally posted by yobbo II

Can anyone tell me how this water pump, made from tubing and an air pump, works? https://www.youtube.com/watch?v=T-IUUoU2RUI

It doesn't. There's a real pump inside the pond. You can see that, when he plugs the inlet tube, the end of the tube that's inside the water gets lodged in something. Also, there's a (crude) jump cut from 11:13 to 11:14. Just look at the other pond in the background (top right corner). It suddenly gets brighter.

Let's make a simple calculation. He claims that the thing is able to pump 280 m³ in one hour. One m³ is equal to 1000 L, so the rate is 280000 L of water per hour. It amounts to 280000/60=4666,7 L per minute, or 280000/3600=77,8 L per second. Almost 80 liters of water on each second. Using a fridge compressor. Of course it doesn't work.

Bullshit, scam, clickbait. Call it whatever you want. If you don't believe me, his next video should convince you:


For Chrissake.

[Edited on 6-3-2024 by bnull]

The Chrissake is directed to the pump guy, not you. Those Physics violators make me real mad.

[Edited on 6-3-2024 by bnull]

Thanks bnull,

Perhaps the 'for christsakes' should be directed at my too!

I did notice the LARGE 280m^3

There a a few more dudes going with the same idea. Is it for the ad's and they get paid?

Anyhow reading the comments I had to laugh. Most not in english so I cannot understand.

'According to fluid mechanics, this is impossible. Are you hiding a pump somewhere?'

Some not so great english but funny.

'Very informative... I try this in my newly buy refrigerator... And now I'm at the hospital,, because my wife hit me with the newly buy hammer.. '

I will reward my self with the *

Yob

*Appologies Yob, but you deserve it.




[Edited on 6-3-2024 by yobbo II]

Quote: Originally posted by yobbo II

There a a few more dudes going with the same idea. Is it for the ad's and they get paid?

Quote: Originally posted by yobbo II

'Very informative... I try this in my newly buy refrigerator... And now I'm at the hospital,, because my wife hit me with the newly buy hammer.. [Edited on 6-3-2024 by yobbo II]

Quote: Originally posted by mr_bovinejony

This is probably a bit of a stretch but I vaguely remember a procedure with triphosgene that says it can be heated at 80c to release a very slow stream of the gas, the most controllable reaction with the stuff I have read about. It may have been in a phosgene book but I can't find it. Anyone have any idea where this idea may have come from?

Hmm. Could it be this book?




[Edited on 18-3-2024 by bnull]

Could someone tell me what is meant by the feature on these true RMS meters?

AC + DC Measurement


The meters are at this link>

https://www.aliexpress.com/item/1005003126913969.html?src=go...
It is circled on the picture

TIA,
Yob



[Edited on 27-3-2024 by yobbo II]

Quote: Originally posted by yobbo II

Could someone tell me what is meant by the feature on these true RMS meters? AC + DC Measurement The meters are at this link> https://www.aliexpress.com/item/1005003126913969.html?src=go... It is circled on the picture TIA, Yob [Edited on 27-3-2024 by yobbo II]

Quote: Originally posted by yobbo II

Could someone tell me what is meant by the feature on these true RMS meters? AC + DC Measurement

When the voltage has a component AC and a component DC (DC offset), ordinary meters measure either the AC component or the DC component but not both at the same time. The AC+DC meter measures both and outputs this:
$$V_{RMS_{(AC+DC)}}=\sqrt{V_{DC}^2+V_{RMS_{AC}}^2}.$$
It's for those times when you want to know the power dissipation in a resistor, for example.

Edit: Victim of ninja attack because of a typo in LaTeX. You won't get me next time, B(a)P, mark my words.

[Edited on 27-3-2024 by bnull]

Quote: Originally posted by bnull

Quote: Originally posted by yobbo II   Could someone tell me what is meant by the feature on these true RMS meters? AC + DC Measurement When the voltage has a component AC and a component DC (DC offset), ordinary meters measure either the AC component or the DC component but not both at the same time. The AC+DC meter measures both and outputs this: $$V_{RMS_{(AC+DC)}}=\sqrt{V_{DC}^2+V_{RMS_{AC}}^2}.$$

Quote: Originally posted by wg48temp9

If you mean it performs that sum then that is incorrect. A true rms meter simple calculates the rms of the signal be it AC, DC or a combination of both.

"AC+DC measurement: Measure signals with AC and DC components (including various waveforms)
Ordinary multimeters can only measure pure AC/DC signals. If the measured AC signal is mixed with the DC signal, the AC signal reading is meaningless. For Uni-Trend’s multimeters with AC+DC function, the AC and DC components are measured together." (https://meters.uni-trend.com/faqs/acdc-measurement/)

"AC and DC are components of a complex signal.
AC Voltage means RMS Voltage for AC component (effective Voltage of alternating current).
DC Voltage means Voltage for DC component (constant Voltage offset).

Both components produce power dissipation on the applied load.
So, you're needs to sum them together in order to get effective Voltage for a total dissipated power.

AC+DC Voltage = sqrt([AC RMS Voltage]^2 + [DC Voltage]^2)" (https://www.eevblog.com/forum/beginners/can-someone-explain-...)

"If you are expecting to include the DC component, but the meter is AC coupled, the results can be dramatically wrong. As a side note, if you need to measure a small AC signal riding on a large DC offset but your meter doesn’t provide AC + DC directly, you can measure the AC component using AC coupling and measure the DC component separately. Then add the two using rms addition:
AC + DC =sqrt((AC_rms)²+DC²)" (Make Better AC RMS Measurements with your Digital Multimeter. Application note, Keysight Technologies, 2018. There's a bloody typo in the formula that they never bothered to fix.)

True-RMS Measurement Pt.1: AC vs. AC+DC. "Roger demonstrates the difference between so called "True-RMS" (only AC) and "True-RMS AC+DC" multimeters and a simple AC-averaging multimeter." (https://www.youtube.com/watch?v=LZEie3nAo1E)

Quote: Originally posted by wg48temp9

I don't know about UT8804

That's the one in question:



[Edited on 5-4-2024 by bnull]

I have now had time to view the details of UT8804.

Below is a snip of the selection switch for the UT8804:



I think the symbol next to all the current ranges is intended to indicate mixed AC and DC signals which are measured true rms ie calculating the rms from a set of samples of the signal DC coupled. I think some people are calling this "AC + DC" mode.

On the voltage range there or two different symbols one usually indicates AC and the other DC. I would expect the AC range to be AC coupled and measures the RMS of the AC component. Does the DC position indicate average or rms ?

The UT8803 only uses the mixed symbol that the current ranges of the UT8804 uses. Meaning it only measures true rms DC coupled

I suspect the tick in AC+DC column for the 04 refers to the two voltage ranges, AC range and DC range that the 03 does not have.

I am very interested in these meters as they both have a usb interface. I expect to purchase the 03. If I want to measure the AC component of a mixed AC and DC voltage l I will add a series capacitor to one of the test leads.



[Edited on 4/7/2024 by wg48temp9]

Quote: Originally posted by wg48temp9

I think the symbol next to all the current ranges is intended to indicate mixed AC and DC signals which are measured true rms ie calculating the rms from a set of samples of the signal DC coupled. I think some people are calling this "AC + DC" mode. On the voltage range there or two different symbols one usually indicates AC and the other DC. I would expect the AC range to be AC coupled and measures the RMS of the AC component. Does the DC position indicate average or rms ? The UT8803 only uses the mixed symbol that the current ranges of the UT8804 uses. Meaning it only measures true rms DC coupled I suspect the tick in AC+DC column for the 04 refers to the two voltage ranges, AC range and DC range that the 03 does not have. I am very interested in these meters as they both have a usb interface. I expect to purchase the 03. If I want to measure the AC component of a mixed AC and DC voltage l I will add a series capacitor to one of the test leads. [Edited on 4/7/2024 by wg48temp9]

Quote: Originally posted by mr_bovinejony

Will clemmensen reduce 3 bromo benzaldehyde to 3 bromo toluene or will it remove the bromine?

When using tight steel hose clamps, is there a risk of implosion under vacuum?



And what about steel keck clips

Whatever is clamped by the hose clamp will shrink under vacuum so there will be less stress due to the clamp.
I can't imagine what problem could be caused by steel keck clips.
So I think that both are not a problem/risk.
...........................
A question of my own;
What is the purpose of the ground taper at the top of a Gay-Lussac style pycnometer?

Quote: Originally posted by Sulaiman

Whatever is clamped by the hose clamp will shrink under vacuum so there will be less stress due to the clamp. I can't imagine what problem could be caused by steel keck clips. So I think that both are not a problem/risk. ........................... A question of my own; What is the purpose of the ground taper at the top of a Gay-Lussac style pycnometer?

Quote: Originally posted by jackchem2001

A base bath is said to clean glassware by etching a small layer off the glass. How does this affect ground glass joints? Is the seal compromised (with joint grease) after base bath usage?

Suggestions for grinding/lapping ground glass joints.

How can the Alpha and the Beta CaSO4:0.5H20 have different solubilities (in the long term)?

Perhaps the study did not wait for days/weeks for all to dissolve, ie. the Beta is slower???

Yob

Sulfur Chlorides Using HCl instead of Chlorine