| OCR Text |
Show 111 diseases of the skin and give insight into such cripp1ing diseases as arthritis. So stretching of rat tai1s becomes of genera1 significance. Rigby and co-workers have carried on this work in a successfu1 way in Austraiia. The mechanica1 properties of fibers was another important app1ication of abso1ute rate theory and it 1ed Eyring to consider the more genera1 prob1em of deformation kinetics. One such prob1em is the move- ment of mo1ecu1es in a so1id when p1aced under stress and strain; i.e. p1astic f1ow. Since such movement is associated with the breaking and re-estabTishment of mo1ecu1ar bonds, the deformation process is a chemica1 reaction, or viewed another way, the isomerization of a giant mo1ecu1e. P1astic f1ow then becomes a part of chemica1 kinetics, and the process can be described by abso1ute rate theory. In p1astic deforma- tion, the picture is more comp1ex than for a simp1e chemica1 reaction since f1ow occurs on1y when a system of energy barriers are overcome. When severa1 independent mechanisms contro1 fiow, they form a system of para11e1 barriers. If f1ow occurs on1y when consecutive obstac1es are overcome, the system is a series of barriers. Often, p1astic f1ow can on1y be described as a combination of para11e1 and sequentia1 energy barriers6], (see figure 6) and shou1d be treated 1ike resistances in para11e1 and series e1ectric circuits. The study of deformation kinetics has important consequences for civi1, mechanica1, meta11urgica1 or e1ectrica1 engineers who are interested in the materia1s used in construction as in the manufacture of integrated circuits. Eyring had a picture in his mind of the mechanism invo1ved when he considered viscous f1ow in 1936 and periodica11y has worked on various aspects of deformation since. The most significant |
