Near infra-red spectroscopy of V838 Monocerotis

Near IR, multi-epoch, spectroscopic and photometric observations of the enigmatic, eruptive variable V838 Mon in JHK bands are reported. One of the unusual features is the detection of several strong neutral TiI lines in emission in the K band. From the strength of these lines, the mass of the ejected envelope is estimated to be in the range 10e-7 to 10e-5 M(sun). The spectra also show the strong presence of the first and second overtones of 12CO bands seen in the K and H bands. The CO bands show a complex evolution. Deep water bands at 1.4 and 1.9 micron are also seen later in the object's evolution. Blackbody fits to the JHK photometric data show that V838 Mon has evolved to temperatures between 2400 - 2600 K by approximately 130 days after outburst. The spectra at this stage have the general characteristics of a very cool M giant.Comment: 7 pages, 5 figures, to appear in Astronomy and Astrophysic

Development of BEM for ceramic composites

Progress is summarized in the development of a boundary element code BEST3D, designed for the micromechanical studies of advanced ceramic composites. Additional effort was made in generalizing the implementation to allow the program to be applicable to real problems in the aerospace industry

Development of BEM for ceramic composites

It is evident that for proper micromechanical analysis of ceramic composites, one needs to use a numerical method that is capable of idealizing the individual fibers or individual bundles of fibers embedded within a three-dimensional ceramic matrix. The analysis must be able to account for high stress or temperature gradients from diffusion of stress or temperature from the fiber to the ceramic matrix and allow for interaction between the fibers through the ceramic matrix. The analysis must be sophisticated enough to deal with the failure of fibers described by a series of increasingly sophisticated constitutive models. Finally, the analysis must deal with micromechanical modeling of the composite under nonlinear thermal and dynamic loading. This report details progress made towards the development of a boundary element code designed for the micromechanical studies of an advanced ceramic composite. Additional effort has been made in generalizing the implementation to allow the program to be applicable to real problems in the aerospace industry