Where does annealing collide?

The controlled heating and slow cooling of a metal or alloy to make it softer, relieve internal stress, and remove defects left by working or casting. Réaumur's 1722 L'art de convertir le fer forgé en acier, et l'art d'adoucir le fer fondu gave one of the first systematic studies of how prolonged heating softens iron, and modern metallurgy explains the effect through recovery and recrystallization, reviewed in Humphreys and Hatherly's 2004 Recrystallization and Related Annealing Phenomena. The referent is a physical heat treatment of solid metal, gauged by temperature, holding time, and the resulting grain structure, and it is not a computer search strategy or the pairing of DNA strands that later borrowed the word.[1][2]

Unit

One heat treatment of a metal piece, set by temperature and holding time

Recovery means

During slow cooling the strained lattice recovers as dislocations rearrange and new strain-free grains grow

Measured by

Assessed by soaking temperature and time, and by the resulting hardness, ductility, and grain size

The pairing of two complementary single strands of nucleic acid into a double helix as a heated solution is cooled, so that matching base sequences find and bind each other. Doty, Marmur, Eigner, and Schildkraut's 1960 Strand separation and specific recombination in deoxyribonucleic acids: Physical chemical studies first showed that separated DNA strands can specifically reassociate, and Marmur and Doty's 1961 Thermal renaturation of deoxyribonucleic acids characterised the reaction and its dependence on cooling. The referent is a molecular binding reaction between complementary strands, gauged by how much duplex reforms, and it has nothing to do with softening a metal or cooling a search algorithm beyond the shared image of order emerging as temperature falls.[3][4]

Unit

One reassociation reaction between complementary strands in solution

Recovery means

Slow cooling below the melting temperature lets correctly matched strands find each other and reform the duplex

Measured by

Followed by the drop in ultraviolet absorbance, or by the fraction of DNA that has returned to double-stranded form

A stochastic method for finding a near-optimal solution to a hard problem by imitating the slow cooling of a metal: the algorithm accepts worse moves with a probability that shrinks as a control parameter called temperature is lowered, so it can escape poor local optima early and settle into a good one late. Kirkpatrick, Gelatt, and Vecchi's 1983 Optimization by simulated annealing introduced the method and named it after metallurgical annealing. The referent is a computational search procedure, gauged by the cost of the solution found and the running time, and it is a metaphor drawn from metal treatment, not the physical heating of metal or the pairing of DNA strands.[5]

Unit

One run of the search over a problem's space of candidate solutions

Recovery means

Not applicable

Measured by

Assessed by the cost or quality of the solution found and the number of iterations or running time used