Why So Many Units?...

Jeff Liebermann wrote:

Nope. The purpose of SI was to honor dead scientists before they were
forgotten.

Like the famous professors Kilogramov and Metrovich? ;-)

If you can\'t solve the problem, become part of the problem:
\"List of humorous units of measurement\"
https://en.wikipedia.org/wiki/List_of_humorous_units_of_measurement

LOL! The attoparsec happens to be about an inch. :->

Best regards, Piotr
 
In article <5rlbhfdvkvr2de87ibk4ud4oimvh29nrs9@4ax.com>,
jeffl@cruzio.com says...
Add to your list, ...
hPa (hectopascals or 100 Pa)

That\'s what I have been accustomed to hearing European coastal weather
forecasters using. Not sure that SI allows for any multiplier other than
powers of 1000...
 
In article <5rlbhfdvkvr2de87ibk4ud4oimvh29nrs9@4ax.com>,
jeffl@cruzio.com says...
Add to your list, ...
hPa (hectopascals or 100 Pa)

That\'s what I have been accustomed to hearing European coastal weather
forecasters using. Not sure that SI allows for any multiplier other than
powers of 1000...
 
In article <5rlbhfdvkvr2de87ibk4ud4oimvh29nrs9@4ax.com>,
jeffl@cruzio.com says...
Add to your list, ...
hPa (hectopascals or 100 Pa)

That\'s what I have been accustomed to hearing European coastal weather
forecasters using. Not sure that SI allows for any multiplier other than
powers of 1000...
 
mandag den 20. juli 2020 kl. 20.41.08 UTC+2 skrev Mike Coon:
In article <5rlbhfdvkvr2de87ibk4ud4oimvh29nrs9@4ax.com>,
jeffl@cruzio.com says...

Add to your list, ...
hPa (hectopascals or 100 Pa)

That\'s what I have been accustomed to hearing European coastal weather
forecasters using. Not sure that SI allows for any multiplier other than
powers of 1000...

https://en.wikipedia.org/wiki/Hecto-
 
mandag den 20. juli 2020 kl. 20.41.08 UTC+2 skrev Mike Coon:
In article <5rlbhfdvkvr2de87ibk4ud4oimvh29nrs9@4ax.com>,
jeffl@cruzio.com says...

Add to your list, ...
hPa (hectopascals or 100 Pa)

That\'s what I have been accustomed to hearing European coastal weather
forecasters using. Not sure that SI allows for any multiplier other than
powers of 1000...

https://en.wikipedia.org/wiki/Hecto-
 
On Mon, 20 Jul 2020 10:31:24 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

On Mon, 20 Jul 2020 18:12:53 +0100, Clive Arthur
cliveta@nowaytoday.co.uk> wrote:

On 20/07/2020 16:52, jlarkin@highlandsniptechnology.com wrote:

snip

Weather maps and reports use inches of mercury here. A bad hurricane
can get down to something like 28.

Millibars here.

Shop and tire pressures are in PSI.

How do Europeans measure tire pressure?

Bars - a bar is defined as 100kPa which is pretty much sea-level
atmospheric pressure.

In the UK psi are often used too, though for tyres, not tires.

We use all SI for engineering, except PCB layout is in decimal inches.
At least we don\'t work in fractions. Much.

It\'s a shame an inch isn\'t 25.6mm instead of 25.4mm.

In the early days of Rubylith/Xacto IC design, it was agreed that 1\" =
25 mm.

During the cold war, the Soviets copied a lot of Western chips, except
that the pin spacing was exactly 2.50 mm (not 2.54 mm). This also
applied to card edge connectors.
 
On Mon, 20 Jul 2020 10:31:24 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

On Mon, 20 Jul 2020 18:12:53 +0100, Clive Arthur
cliveta@nowaytoday.co.uk> wrote:

On 20/07/2020 16:52, jlarkin@highlandsniptechnology.com wrote:

snip

Weather maps and reports use inches of mercury here. A bad hurricane
can get down to something like 28.

Millibars here.

Shop and tire pressures are in PSI.

How do Europeans measure tire pressure?

Bars - a bar is defined as 100kPa which is pretty much sea-level
atmospheric pressure.

In the UK psi are often used too, though for tyres, not tires.

We use all SI for engineering, except PCB layout is in decimal inches.
At least we don\'t work in fractions. Much.

It\'s a shame an inch isn\'t 25.6mm instead of 25.4mm.

In the early days of Rubylith/Xacto IC design, it was agreed that 1\" =
25 mm.

During the cold war, the Soviets copied a lot of Western chips, except
that the pin spacing was exactly 2.50 mm (not 2.54 mm). This also
applied to card edge connectors.
 
On Monday, July 20, 2020 at 10:31:35 AM UTC-7, John Larkin wrote:

In the early days of Rubylith/Xacto IC design, it was agreed that 1\" =
25 mm.

Yeah, but \'agreed\' goes out the window if you print up a PCB for
a 28-pin DIP with 2.5mm pin spacing. That last pin misses its
hole by two diameters...

Postscript printers can fine-tune their output, it\'s possible to
adjust a computer graphic to the right size. I\'ve done small boards
with MacDraw... the alternative was to beg access to the big
copy camera.
 
On Monday, July 20, 2020 at 10:31:35 AM UTC-7, John Larkin wrote:

In the early days of Rubylith/Xacto IC design, it was agreed that 1\" =
25 mm.

Yeah, but \'agreed\' goes out the window if you print up a PCB for
a 28-pin DIP with 2.5mm pin spacing. That last pin misses its
hole by two diameters...

Postscript printers can fine-tune their output, it\'s possible to
adjust a computer graphic to the right size. I\'ve done small boards
with MacDraw... the alternative was to beg access to the big
copy camera.
 
On Monday, July 20, 2020 at 10:54:06 AM UTC-7, John Larkin wrote:
On Mon, 20 Jul 2020 19:40:48 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

How do Europeans measure tire pressure?

In \"atmospheres\" or bars. My car has the correct pressure hint plaque
defined in atm. This is the same up to ~1% accuracy, but much clearer to
laymen.

Best regards, Piotr

Is that absolute pressure, or relative to atmospheric? Is a flat tire
0 or 1?

Flat is zero if the gage legend reads \'psig\', and 1 if it is \'psia\'.

A digital tire gage would have a Chinese symbol for this, of course...
 
mandag den 20. juli 2020 kl. 22.40.30 UTC+2 skrev whit3rd:
On Monday, July 20, 2020 at 10:54:06 AM UTC-7, John Larkin wrote:
On Mon, 20 Jul 2020 19:40:48 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

How do Europeans measure tire pressure?

In \"atmospheres\" or bars. My car has the correct pressure hint plaque
defined in atm. This is the same up to ~1% accuracy, but much clearer to
laymen.

Best regards, Piotr

Is that absolute pressure, or relative to atmospheric? Is a flat tire
0 or 1?

Flat is zero if the gage legend reads \'psig\', and 1 if it is \'psia\'.

would be quite odd with a gauge the reads in Bar with a psia/psig legend
 
On Monday, July 20, 2020 at 10:54:06 AM UTC-7, John Larkin wrote:
On Mon, 20 Jul 2020 19:40:48 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

How do Europeans measure tire pressure?

In \"atmospheres\" or bars. My car has the correct pressure hint plaque
defined in atm. This is the same up to ~1% accuracy, but much clearer to
laymen.

Best regards, Piotr

Is that absolute pressure, or relative to atmospheric? Is a flat tire
0 or 1?

Flat is zero if the gage legend reads \'psig\', and 1 if it is \'psia\'.

A digital tire gage would have a Chinese symbol for this, of course...
 
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.
 
On Monday, July 20, 2020 at 11:41:38 AM UTC-10, DemonicTubes wrote:
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.

One atmosphere of pressure is 101,325 Pascals metric.

Torque is in units of Joules

The Ohm is events per second.
 
On Monday, July 20, 2020 at 11:41:38 AM UTC-10, DemonicTubes wrote:
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.

One atmosphere of pressure is 101,325 Pascals metric.

Torque is in units of Joules

The Ohm is events per second.
 
On Monday, July 20, 2020 at 5:41:38 PM UTC-4, DemonicTubes wrote:
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.

As far as I\'m concerned, getting the units right is part of the job.
My \'learning units\' story involves making an impedance line for
a helium flow cryostat. I made a factor of ten error in the pressure
(Pascals to atm. IIRC) and made the impedance x10 greater than necessary
(or wanted!)
Since the flow impedance \'recipe\' involved cramming some wire
into a thin SS tube. I wasted a lot of time making the wrong
value of flow impedance. And ~$100 1980 dollars (20 liters)
of liquid helium, discovering my mistake.
I was younger then :^)

George H.
I like ft-lbs when torquing head gaskets and such.
 
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.
 
On Monday, July 20, 2020 at 5:41:38 PM UTC-4, DemonicTubes wrote:
On Monday, July 20, 2020 at 12:23:22 AM UTC-6, Ricketty C wrote:
I thought the point of SI was to unify the use of units so everyone could speak the same language? On this ventilator I am find many ways of expressing the same pressure and flow rates.

Pascals
mmH2O
cmH2O
mBar
and another one I didn\'t even recognize. lol

Likewise I\'m finding flow rates indicated as either
ml/s
SLM (standard liters per minute)

WTF?! Why have multiple units like this? This is all in the same field really. People just like to use different units.

Damn them to hell!!!

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Torque units are equally frustrating. According to SI it is supposed to be Nm. I am always converting Nm, Ncm, ft-lb, in-lb., oz-in., etc.

We are also a chemistry lab. Concentration units...grrr! This is worse. Units can be mass-per-volume or number-per-volume. Depending on the industry we are serving, the preferred units are different. It gets a bit obnoxious constantly converting mg/mL to nanomolar (for instance). Since our software analysis needs everything in molarity, I am often scrambling to find the molecular weight of this that and the other thing. And that is just the metric units!

Always makes me chuckle when somebody says Americans don\'t understand metric. We understand metric just fine, we just also happen to know a bunch of other units and know how to convert between them.

As far as I\'m concerned, getting the units right is part of the job.
My \'learning units\' story involves making an impedance line for
a helium flow cryostat. I made a factor of ten error in the pressure
(Pascals to atm. IIRC) and made the impedance x10 greater than necessary
(or wanted!)
Since the flow impedance \'recipe\' involved cramming some wire
into a thin SS tube. I wasted a lot of time making the wrong
value of flow impedance. And ~$100 1980 dollars (20 liters)
of liquid helium, discovering my mistake.
I was younger then :^)

George H.
I like ft-lbs when torquing head gaskets and such.
 
John Larkin <jlarkin@highland_atwork_technology.com> wrote:
On Mon, 20 Jul 2020 19:40:48 +0200, Piotr Wyderski
peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

How do Europeans measure tire pressure?

In \"atmospheres\" or bars. My car has the correct pressure hint plaque
defined in atm. This is the same up to ~1% accuracy, but much clearer to
laymen.

Best regards, Piotr

Is that absolute pressure, or relative to atmospheric? Is a flat tire
0 or 1?

LOL!
 

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