TA Engineering (General). Civil engineering (General) TH Building construction 29 T Technology (General) 28 TC Hydraulic engineering. Ocean engineering 26 TD Environmental technology. Sanitary engineering 25 HD28 Management. Industrial Management 23 TE Highway engineering. Roads and pavements 19 Q Science (General) 16 GE Environmental Sciences 11 QA76 Computer software 9 TP Chemical technology 8 HD Industries. Land use. Labor 7 HE Transportation and Communications 7 QH301 Biology 5 GC Oceanography 4 TK Electrical engineering. Electronics Nuclear engineering 4 HD61 Risk Management 3 G Geography (General) 2 H Social Sciences (General) 2 L Education (General) 2 NA Architecture 2 QA75 Electronic computers. Computer science 2 QD Chemistry 2 TG Bridge engineering 2 TJ Mechanical engineering and machinery 2 GA Mathematical geography. Cartography 1 GB Physical geography 1 HJ Public Finance 1 K Law (General) 1 QA Mathematics 1