Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants |
|Research Institution||TOKYO INSTITUTE OF TECHNOLOGY |
MORIIZUMI Toyosaka Tokyo Institute of Technology, Faculty of Eng., professor, 工学部, 教授 (80016534)
KRUANGAM Dusit Chulalongkorn Univ., Faculty of Eng., Assistant Professor, Faculty of Eng. ・, Assistant
PANYAKEOW Somsak Chulalongkorn Univ., Faculty of Eng., Professor, Faculty of Eng. ・, Professor
NAKAMOTO Takamichi Tokyo Institute of Technology, Faculty of Eng., Assistant Professor, 工学部, 助教授 (20198261)
STRIYUDTHSAK Mana Chulalongkorn Univ., Faculty of Eng., Assistant Professor, Faculty of Eng. ・, Assistant
DUSIT Kruang Chulalongkorn Univ. ,, Faculty of Eng. ,, Assistance
SOMSAK Panya Chulalongkorn Univ. ,, Faculty of Eng. ,, Professor
MANA Sriyudt Chulalongkorn Univ. ,, Faculty of Eng. ,, Lecturer
|Project Period (FY)
1993 – 1994
Completed (Fiscal Year 1994)
|Budget Amount *help
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1994: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥2,000,000 (Direct Cost: ¥2,000,000)
|Keywords||Gas Sensor / Environmental Monitoring / Chemometrix|
Water environmental monitoring system has been developed. The system consists of sensors array, measuring system and a computer with an artificial neural network algorithm for gas indentification. The system is designed for measuring oxygen, ammonia and hydrogen sulfide dissolved in water solution from river.
1. Sensors fabrication and selection : Thin film tin oxide semiconductor gas sensors were fabricated. Calcium oxide and aluminum were doped to increase the sensor selectivity. It was found that the sensors responded to alcohol, ammonium and acetaldehyde. Thin film and bulk type dissolved oxygen sensor have been also developed. It was found that the thin film type is suitable for disposable use and the bulk type is suitable for long term measurement. The commercial semiconductor gas sensors (Figaro _<800, >813, _<824, >823) were also used for testing the system. It was found that they are suitable for measuring ammonia and hydrogen sulfide.
2. Measurement system : Dip type and flow t
hrough cell type measuring systems have been developed by combining the sensors. They were used to measure samples in solution phase and gas phase respectively. The former one has a detection limit for ammonia and hydrogen sulfide at 2 ppm with the response time of 3 minutes, while they were 100 ppm and 20 seconds for the latter.
3. Recognition algorithm : The artificial neural network with the error back propagation algorithm has been used with the above system to enhance the gas recognition capability. After the network was trained with standard gas, it has been found that the recognition error for hydrogen sulfide and ammonia were 2 ppm and 2-25 ppm, respectively.
4. Measurement of river water : The developed system was used to measure the samples from Chao-Praya river in Bangkok. It was found that the concentration of ammonia and hydrogen sulfide in the samples were lower than 3 ppm, which is the detection limit of the system.
In summary, we have been developed a water quality monitoring system using array sensors tpgether with artificial neural network to enhance the system performance. The system has a detection limit of 3 ppm for dissolved ammonia and hydrogen sulfide. We propose that the system can be modified for measuring gas concentration in 100 ppb range by combining the dip type sensors together with flow through cell system. Less