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Aiming to improve the comprehension of the expansion process of perlite, a numerical study has been carried out, concerning the water vapour bubble growth in softened perlite melt. The physical properties of the melt and temperature history during the expansion process are varied, in order to determine the most influencing parameters. Calculated bubble growth results are compared to experimental data obtained in a previous study, and to industrial expansion results. An extensive literature review has been done to determine the physical properties of raw and expanded perlite, as input values to the numerical model. [ABSTRACT FROM AUTHOR]

We present results from an extensive stick-slip study on PMMA-PMMA dry friction, where we studied the influence of a wide range of normal stresses, loading velocities and roughnesses of the sliding surfaces. In this paper we focus (a) on the analysis of a residual coefficient of friction, i.e., shear stress measured at the end of the slip phase divided by the corresponding normal stress, and (b) on the contact stiffness measured by plotting the relative displacement between sample against the shear stress during the stick phase. It is shown that the residual coefficient of friction (i) decreases as normal stress increases, (ii) shows a slight increase when the roughness of the sliding surfaces increases and (iii) does not vary according to the loading velocity. The contact stiffness proved independent of loading conditions and of the roughness of the sliding surfaces. These results are interpreted in terms of asperity interlocking. [ABSTRACT FROM AUTHOR]

Correction to: Astrophys Space Sci (2018) 363:13910.1007/s10509-018-3365-3The original article has been updated for copyright reasons with Fig. 1 and a too vague formulation intended to give credit to Farnes (2017) for the originally displayed figure. The sentences “JCM explains the confinement of galaxies and their flat rotation curves, as recently showed by Farnes (2017), see Fig. 1. Mysterious dark matter is no longer required, while the mainstream ΛCDM model does.” have been replaced by “JCM explains the confinement of galaxies and the shape of their rotation curves. As we showed in Petit et al. (2001), if one introduces a surrounding repellent negative matter environment, it gives larger rotation velocities at distance, see Fig. 1. Mysterious dark matter is no longer required, while the mainstream ΛCDM model does.” Figure 1 has been replaced. The figure caption of the earlier Fig. 1 has been replaced by “Fig. 1 Circular velocity, after Petit et al. (2001). This can be compared with results from numerical simulations by Farnes (2017)” The original article has been corrected. [ABSTRACT FROM AUTHOR]

From our exact solution of the Janus Cosmological equation we derive the relation of the predicted magnitude of distant sources versus their red shift. The comparison, through this one free parameter model, to the available data from 740 distant supernovae shows an excellent fit. [ABSTRACT FROM AUTHOR]