Where does depletion collide?

In economics, depletion is the drawing-down of a finite natural stock (an ore body, an oil field, a fishery), where every unit extracted today is one that cannot be extracted later, so the owner faces an intertemporal allocation problem. Hotelling's 1931 The economics of exhaustible resources showed that along an efficient depletion path the net price of the resource must rise at the rate of interest, the result now called the Hotelling rule. The referent is the optimal rundown of an exhaustible asset, measured by extraction rate, remaining reserves, and scarcity rent, unrelated to a carrier-free zone in a diode or to thinning stratospheric ozone.[1]

Unit

The extraction path of a finite stock and its scarcity rent over time

Recovery means

A stock may be renewable or augmented by new discovery; for a strictly exhaustible resource, depletion is not reversible

Measured by

Tracked by extraction rates against remaining reserves and the path of net (scarcity-rent) price over time

In semiconductor physics the depletion region is the zone straddling a p-n junction (or under a biased gate) from which mobile carriers have been swept, leaving only fixed ionised dopant charge and a built-in electric field. Shockley's 1949 The theory of p-n junctions in semiconductors and p-n junction transistors set out the electrostatics of this space-charge layer, and Sze and Ng's Physics of semiconductor devices is the standard reference for how its width varies with bias and doping. The referent is a carrier-depleted, charged layer whose width and capacitance govern diodes, transistors, and solar cells. It is the same word as an emptied resource stock or a thinned ozone layer but a distinct physical construct.[2][3]

Unit

The width of the carrier-free space-charge layer and its junction capacitance

Recovery means

The region narrows under forward bias and widens under reverse bias; it is a reversible function of applied voltage, not a permanent loss

Measured by

Extracted from capacitance–voltage measurements, which give depletion width and the doping profile

In atmospheric chemistry, depletion names the loss of stratospheric ozone driven by catalytic cycles, most importantly chlorine atoms liberated from chlorofluorocarbons, each of which can destroy many ozone molecules before being removed. Molina and Rowland's 1974 Stratospheric sink for chlorofluoromethanes identified the mechanism that explains the thinning ozone layer and the polar ozone hole. The referent is the catalytic reduction of an atmospheric constituent, measured in Dobson units of total column ozone; it is the same word as an economic rundown or a semiconductor space-charge layer, but a different construct entirely.[4]

Unit

The reduction in total-column ozone over time

Recovery means

The ozone layer recovers slowly as ozone-depleting substances are phased out and decay, over decades

Measured by

Monitored as total-column ozone in Dobson units by ground and satellite spectrometry