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Abstract

A total of 100 maize and 50 poultry feed samples collected in 1998 at random from nine and eight districts of Haryana, respectively, were analysed for fumonisin B1. The samples were collected from poultry farms, feed manufacturers and markets. Ninety one (91%) maize samples and forty two (84%) poultry feed samples were found to contain fumonisin B1. Fumonisin B1 contamination in the maize samples ranged from 0.1-87.0 ppm. Whereas the poultry feed samples contained fumonisin B1 in the range of 0.02-28.0 ppm. It indicated widespread prevalence of fumonisin B1 in maize and poultry feeds in different areas of Haryana.

Can nanotubes display auxetic behaviour?

“…For values of C b /C α in excess of a critical value (C b /C α ~ 300 nm -2 ), then bond angle variation dominates the deformation mechanism leading to positive Poisson's ratio behaviour. This finding is consistent with the SWNT analytical model of Jindal and Jindal [14] which predicted auxetic behaviour for the case of bond lengths becoming sufficiently flexible with respect to bond angle variation.…”

“…Of these modelling studies, Jindal and Jindal refer to the possibility of negative Poisson's ratio response in carbon SWNTs if the bonds can be made sufficiently flexible [14]. Scarpa et al predict auxetic response for a tubular honeycomb structure having the re-entrant hexagon cell shape [19], consistent with the previous report of an auxetic microfabricated tube having a similar honeycomb geometry [20].…”

“…Jindal and Jindal have used a purely geometrical approach to develop expressions for the longitudinal Poisson's ratio of SWNTs undergoing deformation due to bond stretching and bond angle variation [14] and predict that the Poisson's ratio is dependent on the chirality of the SWNT, but is independent of nanotube diameter for a given chirality.…”

“…From the principle of conservation of energy, W a = U a at equilibrium, and so from equations (3), (12), (14) and (15) we get: …”

“…Modelling approaches that have been adopted to predict SWNT Poisson's ratio include: Molecular Dynamics [5]; Molecular Mechanics [13]; and analytical approaches based on geometry [14], lattice-dynamics [15] and energy equivalent considerations bridging molecular mechanics and continuum mechanics [16][17][18]. Finite Element modelling and an analytical model based on beam flexing have been employed to model the Poisson's ratio of tubular truss-like structures having the tessellating hexagon motif [19].…”