Irwin

Cyclopropane rings are opened hydrogenolytically, e.g., over platinum on platinum dioxide (Adam s catalyst) in acetic acid at 2 - 4 bars hydrogen pressure. The bond, which is best accessible to the catalyst and most activated by conjugated substituents, is cleaved selectively (W.J. Irwin, 1968 R.L. Augustine, 1976). Synthetically this reaction is useful as a means to hydromethylate C—C double bonds via carbenoid addition (see p. 74f. Z. Majerski, 1968 C.W. Woodworth, 1968). 

D. P. Locklin, Economics of Transportation, 7th ed., Richard D. Irwin, Inc., Homewood, lU., 1972. Classic textbook on transportation economics, with strong emphasis on regulation and regulatory history. 

The only previous general review of this class of compound is by Irwin and Wibberley (69AHC(10)149), but individual aspects have been the subject of reviews, and these are referred to in the appropriate Sections in the following discussion. 

Irwin J. Kugelman, John S. Jeris, Joseph J. Santoleri, Thomas F. McGowan 25... 

Irwin J. Kugelman, Sc.D., Professor of Civil Engineering, Leliigh University Member, American Society of Civil Engineering, Water Environmental Federation (Section 25, Waste Management)... 

The elastic stress cannot exceed the yield stress of the material, implying a region of local yielding at the crack tip. Nevertheless, to apply the simple framework of hnear elastic fracture mechanics, Irwin [J. Applied Mechanics, 24, 361 (1957)] proposed that this process zone size / be treated as an effective increase in crack length be. Fracture toughness is then given by... 

H. Tada, P. Paris and G. Irwin, The Stress Analysis of Cracks Handbook, Del Research Corporation, St Louis, 1973 (for Tabulation of Stress Intensities). 

He analyzed dispersion data from 11 field experiments in order to determine the form of the functions fy and f, including release height effects. Irwin (9) has used simplified expressions for these functions where both fy and /, have the form... 

Fig. 20-2. Ratio of second highest 24-hr estimated concentrations from the CRSTER model (47) to measured concentrations as a function of the excess of receptor elevation over stack base evaluation A relative to the stack height h. Names with each symbol are power plants. Source From Turner and Irwin (48).

Turner, D. B., and Irwin, J. S., Comparison of sulfur dioxide estimates from the model RAM with St. Louis RAPS measurements, in "Air Pollution Modeling and Its Application 11" (C. de Wispelaere, ed.). Plenum, New York, 1982. 

Submitted by Irwin B. Douglass and Basil Said Farah. ... 

Irwin, C., and Stiller, A., Carbon products and the potential for coal-derivcd... 

Surjit, S., Coke for the steel industry. In Proceedings cf the Corference on Coal-Derived Materials and Chemicals, ed. T. F. Tonies and C. L. Irwin. West Virginia Univesity, Morgantown, WV, 1991, pp. 1 14. 

Linear elastic fracture mechanics (LEFM) is based on a mathematical description of the near crack tip stress field developed by Irwin [23]. Consider a crack in an infinite plate with crack length 2a and a remotely applied tensile stress acting perpendicular to the crack plane (mode I). Irwin expressed the near crack tip stress field as a series solution ... 

Irwin [23] developed an expression for the mode I stress intensity factor around an elliptical crack embedded in an infinite elastic solid subjected to uniform tension. The most general formulation is given by ... 

The second physical quantity of interest is, r t = 90 pm, the critical crack tip stress field dimension. Irwin s analysis of the crack tip process zone dimension for an elastic-perfectly plastic material began with the perfectly elastic crack tip stress field solution of Eq. 1 and allowed for stress redistribution to account for the fact that the near crack tip field would be limited to Oj . The net result of this analysis is that the crack tip inelastic zone was nearly twice that predicted by Eq. 3, such that... 

G. R. Irwin, Journal of Applied Mechanics, Trans. ASME, Vol. 24, 1957. 

Although Griffith put forward the original concept of linear elastic fracture mechanics (LEFM), it was Irwin who developed the technique for engineering materials. He examined the equations that had been developed for the stresses in the vicinity of an elliptical crack in a large plate as illustrated in Fig. 2.66. The equations for the elastic stress distribution at the crack tip are as follows. 

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