a practical guess.
On a lathe, the tailstock has a rotating sleeve which is the quill. It has an internal taper which harbors a center which centers the workpiece being machined. I think "quill...
Nootropics or "smart drugs" improve the function of the neurotransmitter acetylcholine via muscarinic cholinergic (ACh) receptors which are implicated in memory processes. Furthermore, they have an...