0 a way of walking with one person behind another:
The schoolchildren were told to walk in single file.
Thus, any motion of water\ions along the filter has to be in single file.
When fragments were taken from a single file, the file was cut into sections and these were re-ordered.
These measurements define the length of the channel in which permeant ions and water are constrained to diffuse in single file.
This controller is used for helicopters marching in a single file (for example in a line formation) or at an edge of the formation geometry.
I am not sure whether that ought not to be altered to single file.
My experience of driving along dual highways is that whenever we come to a roundabout we are quite rightly reduced to single file.
There might be a high hedge opposite the grid, and the animals might be coming up in single file towards that grid.
They are all in single file—a mediaeval practice.
