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In the present study, pure poly(dimethylsiloxane) (PDMS) polymer and PDMS-detonation nanodiamond (PDMS-DND) composite with 1wt.% of DND were irradiated under vacuum at room temperature with a 2MeV proton beam with fluences in the 1013–1015cm−2 range. Modification of the structures and properties of the pure polymer and the nanocomposite material were monitored as a function of proton fluence. Specifically, the vibrational dynamics of pure PDMS and PDMS-DND nanocomposites, both unirradiated and irradiated samples, were investigated using Raman and Fourier transform infrared spectroscopy (FTIR). The Raman and FTIR spectra of the PDMS and PDMS-DND composites exhibit an overall reduction in intensity of all vibrational bands of the irradiated samples. The changes in relative intensities of the characteristic vibrational bands as a function of irradiation fluence indicate that cleavage of the backbone (Si–O–Si) PDMS chains was most pronounced. Importantly, structural degradation of PDMS-DND composites takes place at an order of magnitude higher fluence than for pure PDMS, indicating the potential of using DND-based polymer composites for application in high radiation environments. The appearance of strong photoluminescence following irradiation was more pronounced for PDMS-DND composites as compared to pure PDMS.

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The paper presents yet another elegant solution to the classical problem of maximizing the range of a projectile fired from above or from below the horizontal target plane. The method makes use of the envelope of the family of the projectile trajectories and it not only solves the original problem, but can be applied to maximize the projectile range on a target surface of arbitrary shape. Three different ways of deriving the equation of the envelope are shown. As an example the range of a projectile is maximized on a parabolic target surface. The envelope can also be used to minimize the kinetic energy of a projectile given the target point.