The phrase "ascertained when" is correct and usable in written English.
It can be used in contexts where you want to indicate the time or condition under which something was determined or discovered.
Example: "The results of the experiment were ascertained when the final data was analyzed."
Alternatives: "determined when" or "established when".
We haven't ascertained when they're ready for that and how we're going to organise that, but they certainly want to".
An extraordinary shift of the antiferrodistortive transition temperature (Ta) is ascertained when just a small percentage of any of the dopants is used.
In all cases, the force change difference from installation is reported and is therefore a minimum uplift force compared to background conditions, which can only be ascertained when thermal sheet deformation is maximally inward during the winter months (December March).
Since only weak staining for GAG and collagen type II was observed for the construct engineered without CDMP1, the induction effect on the fibrocartilage engineering can be ascertained when using DFs as seed cells.
From that point, it can be ascertained when a particular speech or data session started or ended.
While the biodiesel properties for strain 3589 were ascertained when grown on glucose as well as WCO media those for strain 3472 were carried out for the strain grown on WCO.
The approach ascertains when the system needs to undergo maintenance, repair and overhaul before failure occurs.
But it is practically impossible to ascertain when Flaubert's self-mockery is contrived, and to resist its subversiveness.
Experts have been unable to ascertain when the Kaigetsudō studio ceased to exist, though little is traceable to it beyond 1716.
To ascertain when that would be, I found my way to the captain's bridge and explained my query to the ship's navigation officer, Takeshi.
Last night Dirk Vande Beek, Mr. Cheney's spokesman, said he was trying to ascertain when the Cheneys' full tax returns may be disclosed.
