Design and construction 142 Management 72 Materials 42 Quality control 35 Maintenance and repair 34 Purification 33 Standards 32 meer ... Environmental aspects 28 Testing 28 Water 27 Planning 26 Safety measures 26 Equipment and supplies 25 Electronic apparatus and appliances 24 Electronics 24 Production management 24 Sewage 22 Six sigma (Quality control standard) 22 Data processing 21 Integrated circuits 21 Electric power systems 20 Mathematics 20 Signal processing 20 Buildings 19 Project management 19 Electrical engineering 18 Measurement 17 Construction industry 16 TECHNOLOGY & ENGINEERING / Mechanical 16 Transmission 16 minder ...