Irreversible effects

A discussion of the adsorption of water on oxides would be incomplete without some reference to the irreversible effects which are often encountered when samples of oxide, hydroxide or oxide-hydroxide are exposed to the vapour. These effects ( low-temperature ageing ), which manifest themselves in changes in surface area, in pore structure and sometimes in the lattice structure itself, are complex and difficult to reproduce exactly. ... 

Of course, real changes can never be ideally efficient, and some work will be lost in irreversibilities (e.g. friction). Equation (5.17) then gives us an over-estimate of Wf. But it is very difficult to calculate irreversible effects in materials processes. We will therefore stick to eqn. (5.17) as the best we can do ... 

Hecdth effects data come from three types of studies clinical, epidemiological, and toxicological. Clinical and epidemiological studies focus on human subjects, whereas toxicological studies are conducted on animals or simpler cellular systems. Ethical considerations limit human exposure to low levels of air poUutants which do not have irreversible effects. Table 7-1 lists the advantages and disadvantages of each type of experimental informahon. 

Toxic danger of very serious irreversible effects through inhalation... 

Very toxic danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed... 

Harmful possible risk of irreversible effects through inhalation and in contact with skin... 

AUEC = 1.44 Tl /2 (Emax/H) ln( 1 + (Co/CE50) A/Z) For irreversible effects no ceiling concentration is assumed the incremental increase in concentrations and the absolute height of the peak might be more impacting. 

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