TA Engineering (General). Civil engineering (General) 64 TK Electrical engineering. Electronics Nuclear engineering 56 TJ Mechanical engineering and machinery 27 TD Environmental technology. Sanitary engineering 20 TP Chemical technology 8 GE Environmental Sciences 3 T Technology (General) 3 TC Hydraulic engineering. Ocean engineering 3 HD Industries. Land use. Labor 2 QD Chemistry 2 TH Building construction 2 TS Manufactures 2 Biodiesel 1 Business 1 Control Systems 1 Environmental studies 1 Environmentalism 1 HD28 Management. Industrial Management 1 HJ Public Finance 1 Hydroelectric power plants 1 IEC 61499 1 IEC 62443 1 Industrial Control Systems 1 Liquid chromatography with tandem mass spectrometry 1 Mussel fisheries 1 Optimal Control 1 Q Science (General) 1 QA75 Electronic computers. Computer science 1 QA76 Computer software 1 Quadrotor 1