Overload Retardation

It has been long observed by many researchers [27-35] that any single overload imposed during a constant amphtude cycling results in a retardation of the crack growth in the following cycles. Fig. 11.24 [33] is a significant example of this phenomenon known as overload retardation. A series of specimens of type 2024-T3 aluminum alloy have been subjected to different load histories indicated as A, 

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Cotterill, P.J., Knott, J.F. Overload retardation of fatigue crack growth in 9 %Cr I %Mo steel at elevated temperatures. Fatigue Fract. Eng. Mater. Struct. 16(1), 53-70 (1993)... 

Bernard, P.J., Lindley, T.C., Richard, C.E. Mechanisms of overload retardation during fatigue crack propagation. ASTM STP 595, 78-97 (1976)... 

G will generate an excess power compared to Gy. Therefore while G will operate as a generator, Gy. receiving power from G, will operate as a synchronous motor. Since G is overloaded compared to Cy. it will tend to retard, and Gy, receiving power from G, will tend to accelerate. The net effect would be that both generators will tend to synchronize on their own once again. 

Finally, an officially updated definition of the retardation factor, R, issued by lUPAC is important to the whole field of planar chromatography (the linear and the nonlinear TLC mode included). The importance of such a definition has two reasons. First, it is promoted by the growing access of planar chromatography users for densitometric evaluation of their chromatograms and second, by the vagueness of the present definition in the case of skewed concentration profiles with the samples developed under mass overload conditions. 

Defects of complex III. Like defects of complex I, these can be due to nDNA mutations or to mtDNA mutations. The only nuclear defect described thus far does not affect a complex III subunit, but an ancillary protein needed for proper assembly, BCS1L. Mutations in BCS1L can cause a Leigh s-syndrome-like disorder or a fatal infantile disease called GRACILE (growth retardation, aminoaciduria, cholestasis, iron overload, lactacidosis, and early death). 

Fatigue crack propagation in polymers are known to be retarded by large overloads under certain circumstances This has been attributed to crack tip... 

Fellman V, Rapola J, Pihko H, Varilo T and Raivio KO (1998) Iron overload disease in infants involving fetal growth retardation, lactic acidosis, liver hemosiderosis and aminoaciduria. Lancet 351, 490-493. 

The results obtained using the screening techniques in mentally retarded children prompted us to try to study some inborn errors in animal models . Experimental phenylketonuria, for example, can be simulated by overloading with phenylalanine or by inhibiting the phenylalanine hydroxylase with /7-chlorophenylalanine. We have used both /w hloro-phenylalanine and esculin (to block the dihydropteridine reductase reaction), a treatment which leads to a complete inhibition of the enzyme< > > (Fig. 2). 

Source D.E. Matejczyk etal., Fatigue Crack Retardation Foliowing Overloads in Inconel 718, Ti-5Al-2.5Sn, and Haynes 188, Advanced Earth-to-Orbit Propulsion Technology 1986, Vol 2, I SA Conference Publication 2437,1986, p 205-219... 

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