Danger destructive process

The durability is always examined in situations when certain destructive processes are to be foreseen as unavoidable due to environmental influences and as a result of exploitation. However, one particular aspect of all damage and destruction processes should be examined carefully for every practical problem its rate. The rate of a destruction process decides whether the effects are or are not dangerous during the lifetime of the structure. Consequently, the appropriate measures to prevent appreciable negative results should be applied to ensure the safety and serviceability of the structure (Sarja 2000 Naus 2003). Analytical, experimental and simulative methods are used to solve the problem of how to predict the performance of a strucmre in given conditions. In those methods, the interaction of damage modes should be considered properly and incorporated in predictions. 

When concrete structures are subjected to variations of temperature below zero and to the freezing of water solutions in the pore system, then exposure to destructive processes of the cement-based matrices is serious. An increase in the volume of water in the pores when it is transformed into ice is approximately 9% and it may produce important internal stresses, inducing cracks and spallings. This is particularly dangerous in the following situations ... 

Communities near chemical weapon storage depots in the United States are understandably worried about accidental spills or releases. M55 rockets containing large quantities of sarin (SB) are of particular concern. Some of this ordnance has been known to leak, and there is a very small risk of explosion from propellants. Extra safety precautions have been instituted to ensure safe incineration and to limit the amounts of effluent released into the environment. Despite the risks inherent in the destruction process, the dangers in allowing the weapons to rust and leak have been determined to be greater than carrying out the disposal. 

The most dangerous and destructive explosions in the chemical process industries are vapor cloud explosions (VCEs). These explosions occur in a sequence of steps ... 

The use of industrial chemicals with less explosive potential makes the process more intrinsically safe. Most dangerous explosions come from large clouds of flammable material which find an ignition source. Flixborough (Lees, 1996) is an example of the destruction caused by such an incident. 

Potassium hydroxide is an extremely dangerous substance because of its destructive effect upon the eyes. Precipitates, when heated with KOH solution, tend to bump. Suitable precautions should therefore be taken the process should be carried out in the fume cupboard, and protective eye-glasses should be worn. 

The collapse of the USSR in the late 1980s and early 1990s was a step forward in controlling chemical weapons. However, by this time, destruction of chemical weapons was becoming increasingly difficult due to environmental issues. Incineration is now the only acceptable method of disposal and as yet only a limited number of suitable incinerators exist as the process is dangerous and expensive. 

Last but not least, it should be strongly emphasized that the immense complex biosphere developed during a very long evolutionary process is very sensitive to rapid deviations above or below critical limits. Thus, hidden dangers exist to distort the above mentioned mechanisms by mankind s work to a point of no return leading to nearly complete destruction of the basis of life of all higher organized animals. 

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