On Fri, 15 Dec 2017 17:17:31 +0100
Mike Cook wrote:
> > The original paper in question is [1]. As with the nitrogen vacancy
> > clocks, which also trap nitrogen within a Carbon lattice, these have the
> > drawback of quite high temperature coefficients, Harding et al measured
> > 89ppm/K.
>
> I
> Le 15 déc. 2017 à 14:06, Attila Kinali a écrit :
>
> On Fri, 8 Dec 2017 09:40:29 -0800
> Tom McDermott wrote:
>
>> Researchers at Oxford U. have fabricated an atomic reference based on
>> a single nitrogen molecule inside a 60-atom carbon sphere ("Fullerene").
>> The cage of carbon isolates
On Fri, 8 Dec 2017 09:40:29 -0800
Tom McDermott wrote:
> Researchers at Oxford U. have fabricated an atomic reference based on
> a single nitrogen molecule inside a 60-atom carbon sphere ("Fullerene").
> The cage of carbon isolates the nitrogen from external electric fields,
> and they've develop
Citerar Mark Sims :
In the standards definitions that include "at sea level", the
question these days is "which sea level?". As ocean temperature
changes sea level will change (except maybe in Washington DC). Will
the standards be amended to include something like "at sea level in
1990
A 30 cm daily vertical offset is pretty typical. I've seen over 45 cm.
Horizontal offsets are usually less than +/- 75 mm per day with the longitude
displacement typically twice the latitude displacement.
Heather uses a standard model (see
http://geodesyworld.github.io/SOFTS/solid.htm) to c
Checkhttps://en.wikipedia.org/wiki/Earth_tide
According to that, a foot of motion is easily plausible.
The Wiki article says that displacements around a meter in the solid
crust can be seen over the right intervals. This must wreak havoc in
VLBI geodesy work, except that for some in the fiel
Hi
Just as there are Time Nuts, there are Tide Nuts (I suppose it’s capitalized
…).
There is a a lot of data out there on just what sort of solid tides one might
see at this or that point.
Bob
> On Dec 10, 2017, at 7:29 AM, Azelio Boriani wrote:
>
> Is that a Trimble Thunderbolt? Is there
Is that a Trimble Thunderbolt? Is there a way to compute the uncertainties?
On Sun, Dec 10, 2017 at 2:42 AM, Tom Holmes wrote:
> Mark...
> You're place really moved a foot in 48 hours? Impressive and scary!
>
> From Tom Holmes, N8ZM
>
>> On Dec 9, 2017, at 8:19 PM, Mark Sims wrote:
>>
>> Which g
Mark...
You're place really moved a foot in 48 hours? Impressive and scary!
>From Tom Holmes, N8ZM
> On Dec 9, 2017, at 8:19 PM, Mark Sims wrote:
>
> Which gets real fun with things like solid earth tides getting involved.
> Lady Heather can now calculate and plot solid earth tides. Over t
Which gets real fun with things like solid earth tides getting involved. Lady
Heather can now calculate and plot solid earth tides. Over the last 48 hours
my place moved up/down 315 mm and gravity changed 186 microgals... and that
was a rather stable period.
--
> A 1 meter
Yep, to paraphrase Bunker Hunt's "a billion dollars ain't what it used to
be"... a nanosecond (or picosecond) ain't what it used to be. Things that used
to be insignificant n'th order theoretical nuisances are now very real
significant problems.
> But it's not one-to-one as y
Mark,
> In the standards definitions that include "at sea level", the question these
> days is "which sea level?".
Chris,
> So does that mean e.g. NIST and BIPM need to measure the acceleration at
> their respective locations to within parts in 10^17 or 10^18 in order to
> compare their frequen
Hi
If the frequency sensitivity is 1x10^-13 / G you don’t need a lot of precision
in your measurement of G. The same issues apply to things like magnetic
field and the rest.
Bob
> On Dec 9, 2017, at 4:02 PM, Chris Caudle wrote:
>
> On Sat, December 9, 2017 2:39 pm, Magnus Danielson wrote:
>>
Hi,
On 12/09/2017 10:02 PM, Chris Caudle wrote:
On Sat, December 9, 2017 2:39 pm, Magnus Danielson wrote:
The standard acceleration is internationally agreed at 3rd CGPM in 1901
to be 9.80665 m/s^2.
So does that mean e.g. NIST and BIPM need to measure the acceleration at
their respective loca
On Sat, December 9, 2017 2:39 pm, Magnus Danielson wrote:
> The standard acceleration is internationally agreed at 3rd CGPM in 1901
> to be 9.80665 m/s^2.
So does that mean e.g. NIST and BIPM need to measure the acceleration at
their respective locations to within parts in 10^17 or 10^18 in order
Hi,
On 12/09/2017 09:13 PM, Bob kb8tq wrote:
Hi
I suspect that at the practical level, you define standard atmospheric
pressure, standard
gravity, standard magnetic field ….. and on down the list. At some point “sea
level” becomes
a redundant expression.
The standard acceleration is interna
Hi
I suspect that at the practical level, you define standard atmospheric
pressure, standard
gravity, standard magnetic field ….. and on down the list. At some point “sea
level” becomes
a redundant expression.
Bob
> On Dec 9, 2017, at 2:14 PM, Mark Sims wrote:
>
> In the standards definitio
On 12/9/17 11:14 AM, Mark Sims wrote:
In the standards definitions that include "at sea level", the question these days is "which
sea level?". As ocean temperature changes sea level will change (except maybe in Washington DC). Will
the standards be amended to include something like "at sea le
In the standards definitions that include "at sea level", the question these
days is "which sea level?". As ocean temperature changes sea level will change
(except maybe in Washington DC). Will the standards be amended to include
something like "at sea level in 1990" or will the value being de
Hi
If you dig back into the various papers on the subject (and the proceedings
that log the post paper questions) the issue of “can we trust the
implementation?”
does indeed come up. It’s come up for at least the last 50 years that I’m aware
of.
The basic argument runs that for fundamental stand
So we leave the scientific considerations and delve into the philosophical
basis. Somewhere down the line, a standard has to be established, to which all
others can be compared. How good this standard is doesn't matter, as long as
it's stable. But how does one measure stability? Against wha
There is a piece missing for me in the articles I have found on new atomic
standards.
This is what I (think I) do understand:
Quantum properties of the atoms can be interrogated using various RF or
optical means to servo the frequency of an oscillator (which could be a
laser based optical oscilla
I saw that about the N atom trapped inside a C60 molecule, but also
took note of the present cost of the material. I wonder how much is
going to be required to make a good standard.
Dana
On Fri, Dec 8, 2017 at 11:40 AM, Tom McDermott wrote:
> There's an interesting article in the December 201
https://www.google.com/amp/s/spectrum.ieee.org/semiconductors/materials/to-build-the-worlds-smallest-atomic-clock-trap-a-nitrogen-atom-in-a-carbon-cage.amp.html
> On Dec 8, 2017, at 10:38 AM, Ulrich Rohde via time-nuts
> wrote:
>
> Impressive, Ulrich
>
> In a message dated 12/8/2017 12:41:23
Impressive, Ulrich
In a message dated 12/8/2017 12:41:23 PM Eastern Standard Time,
tom.n...@gmail.com writes:
There's an interesting article in the December 2017 issue of IEEE Spectrum.
Researchers at Oxford U. have fabricated an atomic reference based on
a single nitrogen molecule inside
There's an interesting article in the December 2017 issue of IEEE Spectrum.
Researchers at Oxford U. have fabricated an atomic reference based on
a single nitrogen molecule inside a 60-atom carbon sphere ("Fullerene").
The cage of carbon isolates the nitrogen from external electric fields,
and the
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