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The finite element method has here been used to determine stress concentration factors due to axial loading applied to axisymmetric, external projections on hollow tubes. A range of tube and projection dimensions have been covered by the investigation. There is good agreement between the present results and previously published data. The results are presented in a manner which allows stress concentration factors to be quickly determined, for any shape within the range covered by the investigation.

Following weak plane shock diffraction at a knife-edge situated in a duct, a two-dimensional vortex sheet springs from the salient edge. The method of ‘vortex discretization’ is used, in conjunction with a Schwarz-Christoffel transformation, to develop a two-dimensional potential model for this constrained form of vortex generation. The analysis is independent of empirical parameters and describes, qualitatively, the pattern of streamlines through the orifice.Flow-visualization photographs are presented which illustrate the spiral shape of the starting vortex. Although of a limited nature, quantitative experimental vortex growth rates have been obtained and are compared with initial growth rates predicted theoretically. The results are discussed together with other aspects of the problem, including the limitations of the theory.An extension of vortex discretization is developed whereby the pressure distribution remote from the vortex sheet can be calculated. The combination of flow separation and the associated static wall pressure distribution gives theoretical insight into the mechanism of flow through an orifice.

Single crystals of mixed methyl-(2,4-dinitrophenyl)-aminopropanoate (MAP): 2-methyl-4-nitroaniline (MNA) have been grown from solution using a 40:60 mixture of ethanol and ethyl acetate. Formation of an equimolar complex is confirmed by x-ray diffraction studies. The complex crystallizes in the monoclinic space group P21. The lattice parameters are a=6.9196(±0.005) Å; b=7.673(±0.008) Å; c=18.554(±0.001) Å; and β=92.547(±0.006)0. b axis is the unique twofold axis and there are two molecules per unit cell. The molecules stack along the b axis with MAP atop MNA atop MAP. Details of the molecular orientation are given. The Raman spectra also indicate that the parent molecules are not disturbed in the process of crystallization. The second harmonic generation efficiency of the new material for 1064 nm laser radiation is observed to be the same as that of MAP but lower than that of MNA. The latter is attributed to the absorption at 532 nm in the mixed crystal. The melting point determined by differential scanning calorimetry is 104.30 °C.

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