Alert/information threshold

According to the station measurements, the information threshold has been exceeded on 17 days in the period depicted in Fig. 18.2a. Note that 16 of these exceedances were forecasted correctly. The alert exceedance predicted for July 21 was not observed but the measured values were just below the threshold value. The daily maxima above the alert threshold which were observed on 27-28 July 2006, were not predicted by the model. On these days, local peak emissions obviously caused a sudden and local increase of ozone concentrations around noon for 1-2 h. 

Daily ozone forecasts for Austria have been run during summer 2005 and 2006. The results of the forecasts have been evaluated with measurements of the Austrian air quality network for eastern parts of Austria. Generally the observed exceedances of the information threshold are re-produced well by the model. Days with exceedances of the information threshold were predicted by the model with a probability of 88% during the summer period in 2006. The daily maxima above the alert... 

Downhole Shocks Measurements. An accelerometer in the MWD telemetry tool measures transverse accelerations, or shocks, that may be damaging for the bottomhole assemblies. When acceleration exceeds a certain threshold, the event is signaled to the surface as being a shock. These events versus time or depth are displayed as shock count. This information is used as a warning against excessive downhole vibrations and to alert the driller to change the rpm or weight on the bit [106]. 

Fig. 18.2 (a) Gray area range between highest and lowest maximum observations (hourly average) at stations within the region with maximum predicted on the same and previous days backup run (constant boundary conditions), (b) Scatter-diagram of daily ozone maxima predicted versus observed in ozone region 1 for 2006 (maximum predicted on previous and on the same day, as well as maximum predicted by backup run lines information and alert threshold Directive 2002/3/EC))... 

The threshold of toxicological concern (TTC) concept has been developed to provide criteria for risk assessment decision-making in the absence of detailed information on chemicals. The approach involves estimating a tolerable human exposure value for all chemicals below which there is a very low probability of an appreciable risk to human health (Kroes et al. 2004, 2005), based on their chemical structures, compared to an extensive toxicity database. As utilized by U.S. FDA in their Threshold of Regulation procedure, structural alerts for high-potency carcinogenicity are included, to increase the assurance of safety. 

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