Temperature change, countermeasure

A typical countermeasure used by sleepy drivers is to turn on the air conditioner or open a window. Two aspects of this stimulus can be considered in analyzing it as a countermeasure. The first is the cold temperature of the stimulus, or in the least a change in temperature. There has been very little study of the effectiveness of cold temperature as a countermeasure. The simulated automobile drive study cited above also included a cold-air condition produced by the automobile air conditioner (22). As with the radio, cold air had a minimal and transitory alerting effect. The fact that temperature change may be the critical factor is seen in a study that showed heat (92°F) improved performance from basal levels during sleep deprivation, although the impact was very time-limited (24). 

We happened to find the countermeasure to reduce the occurrence of defective products. In all processes CET supersaturated solution should be cooled down to 5°C because CET is chemically unstable, but during the scale-up experiments the subdivided vials accidentally were kept several times at room temperature for about 15 min due to problems in the high-speed subdividing machine. Any of the above products A, B, and C could have been produced in such a tray, but only A was produced. Immediately, we examined the relationship between the thermal history and the structural change in the supersaturated solution. Fortunately, the method to reproduce the solutions having the structural state at various grades... 

To prevent hot spot occurrence, we evaluated the methods which improved liquid distribution, in the commercial operations. Figure 6 compares changes in the temperature deviation of the first bed during the different runs. The axial number, which is an average of the standard deviation of the temperatures at each level, is defined as an index of a degree of maldistribution. A small number indicates good liquid distribution. We took the countermeasures successively run after run. 

In a gas turbine version of the HTTR, half of the radiation dose is estimated to originate from the silver isotope Ag-llOm. Countermeasures could be either a fuel temperature reduction which would require a change of the core design, or the use of advanced fuel with the most efficient barrier against fission product release, the SiC coating layer, to be substituted by a ZrC layer. The higher retentivity of ZrC against Ag release, however, needs further confirmation [40]. 

Here the crystal structure of the catalyst changes. This can be caused by diffusion of active centers due to excessive temperature, or the pore structure may change. This can happen relatively quickly (e.g., in the production of phthalic anhydride or in ammonia synthesis) or slowly over a longer time period. A possible countermeasure is to artificially pre-age the catalyst (e.g., by tempering), so that the catalyst retains a constant activity over a longer time period. 

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