... at a pressure of 50 MPa ...

[Jack8rkin]

Another way of looking at Jutfrank's comment is that these units of measurement (pressure, voltage, resistance temperature, etc. ) represent one instance of said unit of measurement. Also, there are a multitude of possible temperatures, pressures, voltages, etc., but we only want one particular measurement level (or at least within a limited range).

For example, take #7:


We're only putting one source of power at one time, not multiple sources of power. Additionally, while we could put any voltage we want, we need to limit it to just 75 volts. We only want to put one instance of one particular voltage.

We could of course place multiple sources of multiple different voltage levels across that one lonely resistor, but that's going to yield different results.



While we're dealing with a range of acceptable temperatures here, at any given time the temperature is still only going to be at one particular temperature. While that temperature may fluctuate as much as a thousand degrees, it's still only going to be one temperature at any one particular moment of measurement. As long as it remains within those limits, everything is okay.

Does that help?

Thanks a lot. Your reply sheds a lot of light on what I was asking.
Why I'm asking is because the dictionary I use, Longman Dictionary of Contemporary English, has the fourth entry for the word pressure as follows:

PRESSURE
"4. weight [ uncountable ] the force or weight that is being put on to something
pressure of
The pressure of the water turns the wheel.
the pressure of his hand on my arm"

And then they teach you that you should not use an indefinite article with uncountable nouns--it is either the zero article or the definite article.
And then you see, well, what I pasted from the book...

Turns out live language is more than just the matrix they give you at university. ;-)

 

[White Hat]

The pressure unit of "bar" is not pluralized. You would have a pressure of 5 bar. Not 5 bars.

As for the original question, I think it's simply a valid use of the indefinite article. We have not mentioned the pressure before. "Set the valve output manually to hold a pressure of 5 bar."

Later, "Place the controls into Auto to hold the pressure of 5 bar."

Here they use bar in the singular (e.g., 'On the other hand condensing steam turbines (at nuclear power plants) exhaust steam at a pressure well below atmospheric (e.g. at 0.08 bar or 8 kPa or 1.16 psia) and in a partially condensed state. In relative units it is a negative gauge pressure of about – 0.92 bar, – 92 kPa, or – 13.54 psig.').

Here is another sentence from that source: 'One bar is exactly equal to 100 000 Pa, and is slightly less than the average atmospheric pressure on Earth at sea level (1 bar = 0.9869 atm). Atmospheric pressure is often given in millibars where standard sea level pressure is defined as 1013 mbar, 1.013 bar, or 101.3 (kPa).'

The author is Nick Connor.

 

[SoothingDave]

A reason I am resistant to appending a plural "-s" to "bar" is that I normally see it as either "bara" or "barg." For absolute or gauge measurement. The first example from White Hat above uses "psia" which is the same thing, but in US units.

 

[SoothingDave]

Thanks a lot. Your reply sheds a lot of light on what I was asking.
Why I'm asking is because the dictionary I use, Longman Dictionary of Contemporary English, has the fourth entry for the word pressure as follows:

PRESSURE
"4. weight [ uncountable ] the force or weight that is being put on to something
pressure of
The pressure of the water turns the wheel.
the pressure of his hand on my arm"

And then they teach you that you should not use an indefinite article with uncountable nouns--it is either the zero article or the definite article.
And then you see, well, what I pasted from the book...

Turns out live language is more than just the matrix they give you at university. ;-)

This is discussing what "pressure" is. Your original question is about measurements of pressure. There is a difference.

Measurements are countable. "Go out and record all the pressures and temperatures on the compressor every 15 minutes during the test run."

When you are talking about one specific measurement or setting, then you should use the indefinite article.

 

[Jack8rkin]

This is discussing what "pressure" is. Your original question is about measurements of pressure. There is a difference.

Measurements are countable. "Go out and record all the pressures and temperatures on the compressor every 15 minutes during the test run."

When you are talking about one specific measurement or setting, then you should use the indefinite article.

Thanks. That's what's the Dictionary does not explain.

 

[Barque]

the Dictionary

... the dictionary ...

It isn't a deity, though it might seem like one.

 

[Jack8rkin]

... the dictionary ...

It isn't a deity, though it might seem like one.

I mean the LDOCE mentioned above. (Longman)

 

[Barque]

My point was that there's no need to capitalise the word "dictionary". In fact it's wrong to do so.

 

[Jack8rkin]

My point was that there's no need to capitalise the word "dictionary". In fact it's wrong to do so.

Why?

 

[5jj]

Because it's a common noun, not a name.

 

[Barque]

Why?

I should be asking you why you capitalised "dictionary", rather than you asking me why it should not be capitalised.

What reason do you have to capitalise it?

 

[Jack8rkin]

I should be asking you why you capitalised "dictionary", rather than you asking me why it should not be capitalised.

What reason do you have to capitalise it?

I mean the LDOCE mentioned above. (Longman)

 

[Barque]

It doesn't matter what you mean. In that sentence of yours that I referred to, "dictionary" should not be capitalised.

 

[Jack8rkin]

It doesn't matter what you mean. In that sentence of yours that I referred to, "dictionary" should not be capitalised.

I referred to the book that has a proper name -- Longman Dictionary of Contemporary English.

 

[Barque]

If you'd said Longman's Dictionary, then yes, it needs capitalisation.

But you didn't. So capitalisation is wrong.

 

[Jack8rkin]

If you'd said Longman's Dictionary, then yes, it needs capitalisation.

It is not "Longman's". It's "Longman Dictionary of Contemporary English".

 

[Barque]

I referred to the book that has a proper name -- Longman Dictionary of Contemporary English.

You referred to it by its general name and not a specific one. So no capitalisation.

 

[Jack8rkin]

You referred to it by its general name and not a specific one. So no capitalisation.

Ok. So be it.

 

[Jack8rkin]

Thanks everyone for the explanations.
I think I got my answers.

Thank you all again.

 

[Barque]

It is not "Longman's". It's "Longman Dictionary of Contemporary English".

Ok. So be it.

There's no "so be it". That's how it is.

"Longman's" is an accepted abbreviation for the longer term. That's how people refer to it. It's customary English usage. You're unable to understand it because you don't understand that people refer to it as Longman's for short.