The compressibilities of a num ber of organic vapours have been measured at pressures up to 1 atm. and temperatures ranging from 40 to 130° C. The observed second virial coefficients are compared with values calculated from the critical data by the Berthelot equation. The results show two distinct classes of behaviour. Class I is shown by ethane, ethylene,
n
-hexane, cyclohexane, benzene, diethyl ether, ethyl chloride, chloroform and carbon tetrachloride, where the measured second virial coefficients are in agreement with the calculated values. Class II by acetaldehyde, acetone, acetonitrile, methyl alcohol, where the measured second virial coefficients are consistently very much higher than the calculated values. It is concluded that the vapours of polar substances for which the energy of attraction between molecules, due to dipole interaction or to hydrogen bonding, is larger than
kT
undergo dim erization. This view is supported by thermal conductivity data. The range of validity of the Berthelot equation for both non-polar and polar vapours is examined.
It has been shown that a resonance of the reed contributes significantly to the playing behavior of the single-reed woodwind [S. C. Thompson, J. Acoust. Soc. Am. 66, 1299–1307 (1979)]. As an extended object, the reed is actually expected to possess many resonances, and these have been predicted in FEA calculations [D. Casadonte, J. Acoust. Soc. Am. 94, 1807(A) (1993)] and observed in vibration spectra of isolated reeds [D. H. Keefe and S. Waeffler, J. Acoust. Soc. Am. 94, 1833–1834(A) (1993)]. The current study used holographic interferometry to identify the vibration patterns of a clarinet reed mounted on a mouthpiece, as driven by an acoustic field internal to the mouthpiece. Without a player’s lips to shorten the vibrating section, the lowest frequency and most easily driven resonance is in the region 1500 to 2000 Hz and corresponds to the lowest mode of a rod clamped at one end. The second and third resonances are near 4000 Hz. The second mode displays twisting motion, but with a surprising degree of asymmetry, while the third mode is similar to the second mode of a rod clamped at one end.
The high contact stresses between a railway wheel and rail result in local plastic deformation in both the rail and wheel steel. Optical metallography and hardness testing have traditionally been used to quantify the extent of deformation present; however, these methods only give limited information about the deformation mechanism and the role of microstructure. In this study, electron backscattered diffraction has been used to assess the depth and degree of deformation using the kernel average misorientation function; where the crystallographic misorientation between and within pearlite colonies has been quantified using a local average misorientation function. This technique gives invaluable crystallographic information about the deformed microstructure to aid understanding of the deformation mechanism. The application of the kernel average misorientation function has been modelled for idealised rail microstructures, including after the simulation of deformation via shear, in order to understand how the average kernel average misorientation values are developed under the high levels of deformation seen in rail steels.
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