Research on Genetic Characteristics of Slab Bulge in Continuous Casting Process

Bulge deformation is an important factor that causes inner crack and declines the quality for slab. This has a significant genetic phenomenon in continuous casting process. In order to explain this feature, a two-dimensional FEM model for slab that includes viscoelastic and dynamic characteristic has been built. Positive creep and reverse creep were introduced to explain this mechanism. Roll pitch, shell characteristic, slab withdrawing speed and other process parameters that influence bulge’s genetic level are discussed. A nonlinear equation was suggested to describe the relationships between these factors and genetic level of bulge.

The Peculiar X-ray Morphology of the SNR G292.0+1.8 : Evidence for an Asymmetric Supernova Explosion

A high resolution X-ray image from the Einstein Observatory of the young supernova remnant G292.0+1.8 (MSH11–54), previously noted as peculiar in terms of its spectral and morphological properties at optical and radio wavelengths, also shows an unusual X-ray morphology. Instead of a limb-brightened X-ray shell characteristic of most SNRs, the remnant consists of a central bar-like feature superposed on an ellipsoidal disc of approximately uniform surface brightness. We attribute the bar emission to a ring of oxygen-rich material ejected in the equatorial plane of a massive rotating progenitor, and the uniform disc component to emission from material with roughly cosmic composition heated by the accompanying blast wave. This interpretation provides observational support for the rotating precursor model of a Type II supernova discussed by Bodenheimer and Woosley.

Approximate Roots of Flu¨gge’s Characteristic Equation for the Closed Cylindrical Shell

Two approximate solutions are given for Flu¨gge’s closed cylindrical shell characteristic equation, valid for the lower and higher harmonics, respectively. It is shown that as the harmonic number increases, the roots of Donnell’s characteristic equation do not behave asymptotically like those of the Flu¨gge equation.