Subclass T: General technology
Subclass TA: Civil engineering
Subclass TC: Hydraulic engineering
Hydraulic engineering is the design, construction, and maintenance related to the flow and conveyance of fluids.
Subclass TCA: Ocean engineering
Ocean engineering is the design, construction, and maintenance of boats, oil rigs and other marine vessels or structures.
Subclass TD: Environmental technology
Environmental technology covers engineering to improve or protect the environment, to control pollution and to provide safe natural resources for human use.
Subclass TDA: Sanitary engineering
Sanitary engineering is the design, construction, and maintenance of methods to improve sanitation of human communities, including the disposal of everything from human waste to litter.
Subclass TE: Highway engineering
Subclass TF: Railroad engineering and operation
Subclass TG: Bridge engineering
Subclass TH: Building construction
Building construction covers architectural engineering and the structural engineering of buildings. It includes aspects such as plumbing, heating, ventilation, illumination and decoration.
Subclass TJ: Mechanical engineering and machinery
Subclass TK: Electrical engineering
Subclass TKA: Electronics
Electronics covers electrical circuits and electrical components. This portal also includes computers and computer engineering.
Subclass TKB: Nuclear engineering
Nuclear engineering is the design, construction, and maintenance of applications of nuclear physics; this includes the subject of atomic power.
Subclass TL: Motor vehicles
Motor vehicles covers automotive engineering and the technology of road vehicles such as cars, motorcycles and lorries.
Subclass TLA: Aeronautics
Aeronautics is the design, construction, maintenance and operation of vehicles capable of flight within the Earth's atmosphere.
Subclass TLB: Astronautics
Astronautics is the design, construction, maintenance and operation of vehicles capable of space flight. This portal includes propulsion, control and navigation beyond the Earth's atmosphere.
Child portals: Cassini-Huygens • Space exploration
Subclass TN: Mining engineering
Mining engineering is the theory and application of extracting minerals from the natural environment. It includes prospecting, processing, transportation and machinery involved in this practice.
Metallurgy is the study of metallic elements. It includes their physical and chemical behaviour, their compounds and their alloys.
Subclass TP: Chemical technology
Chemical technology covers the design, construction, and maintenance of applications of applications of physical or life sciences. It includes the manufacture, processing and use of chemical products.
Photography covers the technology and techniques involved in recording images. This includes cameras, film, lighting, cinematography and image sensors.
Subclass TS: Manufactures
Manufactures covers the creation of, and the industry surrounding, manufactured goods and products.
Subclass TT: Handicrafts, arts and crafts
Subclass TX: Home economics