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

[Jack8rkin]

Hello everyone,

Could you please explain why the indefinite article is used with uncountalbe nouns in of-phrases like:

at a pressure of 50 MPa
at a power of 50 MW
at a temperature of 32 F
at a voltage of 440 V

What's the grammar behind this?
Is it at all correct?

 

[White Hat]

I've also noticed that sometimes they say 'by a score of' and sometimes 'by the score of' For instance:

1) The KV girls defeated Lowell by a score of 24-31.
2) In game two, Dartmouth defeated Halifax by the score of 11-1 in five innings.

Is either possible?

 

[Barque]

It'd help if you provided the full sentence.

If a noun is uncountable, it doesn't mean it can't take the definite article. Those phrases refer to a certain specific pressure, a specific temperature, a specific voltage and a specific amount of power. That's why "a" is possible. Depending on the sentence, "the" might be possible too.

"At a power of 50MW" does sound odd to me however because of the word "power" specifically but if you give us the full sentence that might make a difference.

 

[Jack8rkin]

Ok. The full sentences would be like this:

1. "The first MHTGR designed with an annular core had a power of 350 MW(t)."
2. "The moderator water at a temperature of 210°C is used to preheat the feedwater, producing a net efficiency of operation of approximately 29% for Atucha 1 and 32% for Atucha 2."
3. "In the boiler, the heat source is the burnt gas at a temperature of 2000–3000°C."
4. "Steam will be produced at a pressure of 78 Bar"
5. "The reference design for this concept is a 1700-MWe reactor operating at a pressure of 25 MPa with a reactor outlet temperature between 510 C and 550 C."
6. "A typical AA battery has a voltage of 1.5 V."
7. "A voltage of 75 V is placed across a 150-Ohm resistor."

Thank you.

 

[Barque]

In sentence 1, I'd say "... had a power output of ...".
In sentence 4, you need "78 bars", not "78 Bar".
In sentence 7 I'm not sure "placed" is the right word to use with "voltage". Maybe someone else will comment.

The other sentences all seem all right.

 

[Jack8rkin]

In sentence 1, I'd say "... had a power output of ...".
In sentence 4, you need "78 bars", not "78 Bar".
In sentence 7 I'm not sure "placed" is the right word to use with "voltage". Maybe someone else will comment.

The other sentences all seem all right.

You are trying to edit "Nuclear Engineering Handbook" edited by Kenneth D. Kok
But thanks for your opinion.

 

[White Hat]

Ok. The full sentences would be like this:

1. "The first MHTGR designed with an annular core had a power of 350 MW(t)."
2. "The moderator water at a temperature of 210°C is used to preheat the feedwater, producing a net efficiency of operation of approximately 29% for Atucha 1 and 32% for Atucha 2."
3. "In the boiler, the heat source is the burnt gas at a temperature of 2000–3000°C."
4. "Steam will be produced at a pressure of 78 Bar"
5. "The reference design for this concept is a 1700-MWe reactor operating at a pressure of 25 MPa with a reactor outlet temperature between 510 C and 550 C."
6. "A typical AA battery has a voltage of 1.5 V."
7. "A voltage of 75 V is placed across a 150-Ohm resistor."

Thank you.

Most of these seem to have been taken from reliable sources. I've googled some of them word for word. Providing the source could help. (Simul-posted)

 

[Jack8rkin]

Most of these seem to have been taken from reliable sources. I've googled some of them word for word. Providing the source could help.

1-5 are from "Nuclear Engineering Handbook" edited by Kenneth D. Kok.
6, 7 are from a practical problems from ".us" sites.

I'd like to know what's the grammar behind such usage.
It seems to be wrong, but it's there...

 

[jutfrank]

Could you please explain why the indefinite article is used with uncountalbe nouns in of-phrases

I could certainly try, yes. What level of explanation would you like? Could you tell me exactly what you want to know? (I don't want to waste time telling you things you know already.)

What's the grammar behind this?
Is it at all correct?

Yes, of course it's correct. This is essentially about the semantics of indefinite noun phrases.

 

[probus]

In the future @Jack8rkin please give the source of any material you quote rather than write yourself when you first post it. This is a legal requirement we all must comply with in the forum.

 

[Jack8rkin]

I could certainly try, yes. What level of explanation would you like? Could you tell me exactly what you want to know? (I don't want to waste time telling you things you know already.)



Yes, of course it's correct. This is essentially about the semantics of indefinite noun phrases.

It seems that the use of the indefinite article is totally wrong with uncountable nouns as we are taught.
In fact scientific language uses the indefinite article in the provided phrases.
I know that sometimes it is possible in decriptive phrases in fiction literature.
What we have here is not fiction, rather it is precise numbers.
Why not use the definite article here?

 

[Jack8rkin]

In the future @Jack8rkin please give the source of any material you quote rather than write yourself when you first post it. This is a legal requirement we all must comply with in the forum.

I am sorry. I did not mean to violate anyhting. I wanted a general explanation for the "of-phrases" with "a".
Did not think any examples would be needed -- the said phrases are widely used.
In fact it all turned out to be a little too complicated.

 

[jutfrank]

It seems that the use of the indefinite article is totally wrong with uncountalbe nouns as we are taught.

It isn't wrong. Since an indefinite article is used as a determiner, the nouns 'pressure, power, temperature', etc. are best understood as being used here as countable nouns, not uncountable ones.

Why not use the definite article here?

That would be wrong.

 

[SoothingDave]

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."

 

[Skrej]

It isn't wrong. Since an indefinite article is used as a determiner, the nouns 'pressure, power, temperature', etc. are best understood as being used here as countable nouns, not uncountable ones.

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:

A voltage of 75 V is placed across a 150-Ohm resistor.

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.

In the boiler, the heat source is the burnt gas at a temperature of 2000–3000°C.

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?

 

[Barque]

You are trying to edit "Nuclear Engineering Handbook" edited by Kenneth D. Kok
But thanks for your opinion.

Never heard of him. He doesn't sound like a native speaker from his name. If you're suggesting I'm wasting my time correcting his language, you might want to think again. Expertise in nuclear engineering doesn't necessarily mean expertise in English.

 

[Barque]

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

Do you have something to back that up? Not saying you're wrong. I might be.

 

[SoothingDave]

Do you have something to back that up? Not saying you're wrong. I might be.

I was going off of my experience, and the fact that units aren't usually pluralized. We don't say "10 cms" or "10 ins" for centimeters or inches.

There is some disagreement on this, so take what I said as a school of thought and not a definitive rule. It just immediately struck me as odd.

 

[Barque]

"Bar" doesn't have an abbreviation like "cm" or "in". In my experience it's "bars", and in any case that unit isn't used very commonly.

so take what I said as a school of thought and not a definitive rule.

Your post made it sound like a definitive rule. Thank you for clarifying the point.

 

[Jack8rkin]

And may I suggest you lay off the sarcasm? I might be wrong, but I'm someone who was trying to help you. You people who post questions on free forums and then criticise the answers are obnoxious. Perhaps you need a course in manners more than English.

I am awfully sorry. No sarcasm there.
You asked for examples, I tried to provide them. They are all quotes from a book published in the USA or from the US web sites.
My mistake was not mentioning the source.
Sorry again.