Reply to the comment by G. Barbero and N. V. Madhusudana ‘On a theoretical analysis on the influence of non-uniformity of the order parameter on the surface energy in nematics’ (1990, Liquid Crystals, 7, 299)

Abstract

In their comment to our recent paper [I] Barbero and Madhusudana argue that the mathematical problem is ill-posed and thus the consideration should be revised. The objection is based on the ideas published in a set of papers [2–4], where it has been shown that if the K₁₃term is used in the usual nematic free energy density, the function n(z) may be discontinuous at the surface and in this case we have to include second order elasticity ～(V ²n)² into our consideration. In principal, we agree with this objection, although it is very difficult to estimate whether the corresponding contribu-tion to n(z) is essential, because no real problem with second order elasticity has been solved up to now. At the same time it is obvious that if we do not take the K_l3 term into account, the solution of the minimizing problem with the traditional nematic free energy remains correct and does not contradict experimental observations.     

Comments on M.Yu. Zaremski, Chen Xin, A.P. Orlova, I.V. Blagodatskikh, and V.B. Golubev’s Paper “General Features and Specifics of the Kinetics of the Pseudoliving Radical Polymerization of 4-Vinylpyridine and Styrene Mediated by TEMPO”

It is shown through a numerical experiment that, in the presence of extra (spontaneous) initiation, the equilibrium constant and the ratio between the rates of quadratic and reversible terminations cannot affect the rate of pseudoliving radical polymerization. The kinetics of the process in the steady-state region is determined only by the ratio between the rates of additional initiation and quadratic chain termination. Discrepancies between experimental data and theory must be explained with allowance for side reactions that can occur in these complex systems rather than via re-examination of the reliably verified mechanism of pseudo-living radical polymerization.     

Response on “Regulations in the field of residue and doping analysis should ensure a well-defined risk of a false positive declaration” by N. M. Faber

Dr. Faber provided support for a valuable methodology for the comparison of mass spectra. However, since many other factors are involved in the evaluation process before declaring a sample “positive”, i.e. reporting an adverse analytical finding, his conclusions on this subject are incorrect. In this paper a number of arguments are listed showing that Dr. Faber did not take all factors under consideration when making his claims. These factors involve parameters directly related to mass spectrometric criteria, but also to other equally important factors including sample preparation specificity, retention time (since in doping control mass spectrometry is used as part of a hyphenated technique), etc. These arguments clearly illustrate that the risks for a false positive declaration can not be calculated according to Dr. Faber’s proposed methodology. Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher.