TD Environmental technology. Sanitary engineering TA Engineering (General). Civil engineering (General) 25 GE Environmental Sciences 6 TJ Mechanical engineering and machinery 5 HD Industries. Land use. Labor 3 HD28 Management. Industrial Management 3 QA76 Computer software 3 QD Chemistry 3 T Technology (General) 3 Environmental protection 2 GV Recreation Leisure 2 K Law (General) 2 Sewage disposal systems 2 TC Hydraulic engineering. Ocean engineering 2 TH Building construction 2 Treatment, purification, etc 2 Air pollution and its control 1 Applications of electronics 1 Client/server computing 1 Detectors. Sensors. Sensor networks 1 Environmental auditing 1 Environmental pollution 1 Environmental reporting 1 HE Transportation and Communications 1 HG Finance 1 HT Communities. Classes. Races 1 Hydrology. Water 1 Industrial and factory wastes 1 Law enforcement 1 Malaysia 1