The phrase "are open simultaneously" is correct and usable in written English.
It can be used to describe multiple entities or processes that are occurring at the same time.
Example: "The two applications are open simultaneously, allowing users to switch between them effortlessly."
Alternatives: "are open at the same time" or "are open concurrently".
This analysis could be applied accurately only to channels that exhibited frequent stable openings such that the pressure at which two channels are open simultaneously could be determined.
The larger conductance values observed could thus be a result of multiple channels that are open simultaneously.
Indeed, the risk of occasional small back flow created when doors are open simultaneously or when there is a high difference of temperature across an open door has already been considered in the design of ventilation system in healthcare facilities [ 18].
The German government promotes 'shock-ventilation' (Stoßlüften), where all windows are opened simultaneously, fully and briefly, to minimise energy wastage.
At this step, the Ga and Bi cell shutters are opened simultaneously.
Even when all 20 datasets are opened simultaneously, the performance and responsiveness of ReadXplorer is convincing.
Both A and B must be open simultaneously.
These valves will never be open simultaneously and their fail-safe position under loss of signal and loss of motive utility requires special design attention.
By many expert accounts, this is the first time the Northwest Passage over North America and the Northern Sea Route over Europe and Asia have been open simultaneously in at least half a century, if not longer.
Just two weeks after we returned from the High Arctic, satellite images revealed that for the first time in recorded history, both the Northwest Passage in Canadian Arctic waters and the Northeast Passage above Russia were open simultaneously.
Steiner's new and Williams' old briefcase as well as Daniels' case was open simultaneously next.
