The phrase "a useful quantity" is correct and usable in written English.
It can be used when referring to a measurement or value that has practical significance or application in a particular context.
Example: "In our calculations, we found that the temperature change was a useful quantity for determining the efficiency of the process."
Alternatives: "a valuable measure" or "an important figure".
A useful quantity related to the flow of charge is current density, the flow of current per unit area.
It is also a useful quantity to validate seal data, because it provides a single scalar quantity for each profile that depends on both temperature and salinity profiling data.
The first explorations that yielded a useful quantity of specimens and data for scientific study were those of James Cook in 1769 and 1773 74 and of Louis Duperry and Dumont D'Urville in 1824, 1827, and 1840.
Not all biodiversity impacts are directly related to the amount of land taken up by a technology, but it is likely that an energy production technique that takes a lot of land will have a relatively large biodiversity impact, so the total new area impact is a useful quantity to measure.
Thus, CRO is a useful quantity for ion competition estimation.
We show that a useful quantity to calibrate the degree of cooperation is the Shannon entropy.
But made in any useful quantity, these require large amounts of suspicious substances.
Storing an automotively useful quantity of hydrogen in a container the size of a car's gas tank requires enormous compression and expensive composite materials.
While city health inspections capture a wide variety of data that is difficult to obtain from online social media (like the presence of rodents in a restaurant's storage room), the Twitter signal measures a perhaps more useful quantity: a probability estimate of your becoming ill if you visit a particular restaurant.
The basis reproductive number, R 0, is a very useful quantity in mathematical analysis and epidemiological application.
He introduces a very useful quantity: The distribution of signal to interference plus noise ratio (SINR) as cause of mutual interference, as a function of the spacing between vehicles, from a given geometry.
