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Equation 10 · Part 2 · How Materials Discovery and Degradation Actually Work

Symbol t

δ(t)\delta(t)
tt

What this part means

t is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

t is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

where δ(t)\delta(t) is film thickness, δ0\delta_0 an initial thickness, and k a rate constant set by species diffusivity through the existing film — a direct consequence of assuming the rate-limiting step is diffusion across a film whose own thickness is the barrier [ 2 ] . This is a model, not a universal law : the review is explicit that mixed kinetic-and-transport regimes, porous or cracked SEI, and side reactions all produce departures from a clean square-root trend, and reconciling model and experiment remains an open problem [ 2 ] .

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A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the surrounding passage

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