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In the street...

Finally, since 9 January, we're in the street and measuring. Daily routine is checking on the propane liberation system, checking all the instruments in the truck, checking on the webcam and burning the videos onto DVDs, ... etc... the list of daily chores is long and we try to share as much as possible. Here some fast facts...
- Tracer liberation from 10am to 10pm, since the heavy traffic is forbidden up to 8pm
- Tracer concentrations at the other side of the street vary from 0ppb to 200ppb with a propane liberation of 5l/min over 100m of tube. Interestingly, there is a daily reoccuring pattern of low concentrations in the morning and high concentrations in the afternoon into the evening, which is probably due to changing wind direction and ventilation of the street canyon.
- MFC for propane is behaving well. Irregular occuring problems are probably linked to impurities in the tubes and the propane and - up to now - could be remedied by completely opening and closing the MFC several times.
- The BTEX is in the truck and running. We're now looking into a calibration and are currentlyh organising all of the connection necessary for the calibration gas.
- The industrial PC which serves as a data logger could not be fixed. After changing RAM, Harddisk, reinstalling the operating system, and checking the mainboard, I've abandoned to fix it. The computer does not record any data always starting a midnight and probably this is due to a software error.
- The tube is slowly falling apart. Since many motorcycles drive over it and taxis sometimes even park on it, the plastic is slowly giving away. After having supported it with wood on one side, we are now trying to put wood on the other side and fixing it directly to the pavement with screws.
- The LPG sensor which measure the concentrations of LPG inside the tube and switched of the MFC if 50% LEL is exceeded, is not working correctly. A comparison with the second LPG sensor, showed more than a factor 3 difference. We are currently trying to calibrate it with a mix of propane to see where the truth lies. Probably the sensor is not very well adapted to the high humidities in Vietnam.
- After some organizational and personal problems with the helpers we've been allocated by IER, everything is now fine and we have got more or less four half-time working people to help us in the street.
Posted by Oliver Fuhrer on Thursday 25 January 2007 at 15:58