transport of dangerous goods and risk management - Kirilo Savić

TRANSPORT OF DANGEROUS GOODS AND RISK MANAGEMENT 94Figure 11 shows (central) coastal measuring telecommunication unit which has been on the raft for more than 6months, for the purpose of the experiment. It is located inside the raft and it does not take up much space.Picture 11. Coastal measuring telecommunication unit inside the raftPerforming experimental measurements and problems connected with themOver a six month period the values of oxidation-reduction potential in the water and water temperature weremonitored with the minimal effort of the researchers. The functioning of sensors and measuring equipment in theresearch centre was also monitored with a minimal number of interventions on the spot.The working principle of the redox probe is based on the established connection between the platinum andreferential hydrogen electrodes within the probe, which is then placed into the medium (river water, in this case)containing the pollutants that are supposed to be measured. Depending on the composition of water the process ofoxidation or reduction takes place, which is the basis for the calculation and monitoring of the changes inconcentration of pollutants in the water. Redox probe GE 105 represents this process as electric potential between -2000 mV and +2000 mV. These values are relative and they depend on the temperature, pH factor and pressure. Theworking temperature of this probe ranges from 0 to 80° C. Calibration of the probe was carried out before use.Accurate measurements require temperature correction according to the probe manufacturer’s table. That was thereason why a temperature probe was installed during the experiment. The values of this probe diverged from theHMZ temperature probe located on the other bank of the Sava, near Branko’s Bridge, by 0,5 0 C at the most.In the above mentioned research period there were only two interruptions, which were dealt with in our previoswork 4 .The first interruption was due to the reduction of water level on the Sava. A part of the raft was stranded so that theprobe on the other end partially emerged from the water. The irregularities in its functioning and measured valueswere noticed immediately at the control research centre. A team of researchers and their co-workers from Aluxomwent to the location and shortly afterwards they re-installed the probe at the appropriate depth.The second system failure was due to the interruption of data transfer caused by problems in GSM Network of MTSmobile operator. This time, no field work was necessary to re- establish the system. The device was re-activatedremotely, from the command research centre.