Subclass T - Technology (General).

Subclass TA - Engineering (General).

Subclass TC - Hydraulic engineering. Ocean engineering.

Subclass TD - Environmental technology. Sanitary engineering.

Subclass TE - Highway engineering. Roads and pavements.

Subclass TF - Railroad engineering and operation.

Subclass TG - Bridge engineering.

Subclass TH - Building construction.

Subclass TJ - Mechanical engineering and machinery.

Subclass TK - Electrical engineering. Electronics. Nuclear engineering.

Subclass TL - Motor vehicles. Aeronautics. Astronautics.

Subclass TN - Mining engineering. Metallurgy.

Subclass TP -Chemical technology.

Subclass TR - Photography.

Subclass TS - Manufactures.

Subclass TT - Handicrafts. Arts and crafts.

Subclass TX - Home economics.

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