arXiv subjects

Franco Pavese

Publications and source records attributed to Franco Pavese.

6 recordsLinked to original sources

arXiv2018

Is the proposed SI revision, according to the October 2018 BIPM documents, scientifically and formally satisfactory?

The use of the fundamental constants for the definition of the most important measurement units of the International System, was considered a good solution to found it on more solid bases. From further analysis, this solution was found implying a number of consequences underevaluated by the BIPM until the proposal presented for discussion in November 2018 to the CGPM, or at least never clearly explained to the signatories Countries of the Metre Treaty. This lack of clarity will affect the implementations of the revised System in the future. Following previous illustrations, this v.5 of the paper is focusing on some issues of direct impact on the correctness of the new definition and on its implementation: how many digits, supported by the latest experimental values, can be stipulated for the numerical values of the constants; why the present experimental uncertainties do not support the pretended precision of the constants; how inconsistencies affect some constant final database; why the CODATA LSA analysis alone is insufficient to support the stipulated precision of the constants; how the need should be explained of keeping the former base units, in order to preserve their present magnitudes; which is the true base-units/constants relationship; how the now-installed hierarchy between the constants and the base units makes changes in the future metrological pyramid; how to still use the present top national standards in future.

physics.gen-ph↗

arXiv2018

The New SI and the CODATA recommended values of the fundamental constants 2017 compared with 2014, with a Comment to Possolo et al., Metrologia 55 (2018) 29

This note comments on the special CODATA 2017 adjustment of the fundamental constants of July 2017 involved in the revision of the SI (based on: P.J. Mohr et al., Data and Analysis for the CODATA 2017 Special Fundamental Constants Adjustment for the Revision of the SI, Metrologia 2018, September 2017 preprint), with a comparison to the CODATA 2014 adjustment. In Appendix, a comment is also added on the paper Possolo et al., Metrologia 55 (2018) 29 on the Planck constant. The previous versions of this manuscript (also available on ArXiv) were aiming at pointing out some standing features of the present and future CODATA method in the light of the CODATA table of 2014 recommended values for the fundamental constants. A comprehensive discussion on this and related issues is becoming very important in view of the foreseen revision of the International System (SI) of measurement units in 2018. The present features may still raise doubts on a possible mixing of physical reasons of general validity in science with some needs specific of legal aspects of metrology concerning the SI. This illustration was adjourned in version 3 (v3) according to the CCU 2016 draft of the 9th SI Brochure and to the outcomes of its 22th meeting, with a note about the intended need of a 8th digit in the stipulated value of k.

physics.data-an↗

arXiv2017

The ITS-90 after definition of neon isotopic reference composition. Extent of the isotopic effect on previous inter-comparison results

Starting from the end of the past century, the importance has been recognized of the effect of isotopic composition on some of the temperature fixed points for the most accurate realizations of the ITS-90. In the original definition of the latter, dating back to 1990, only a generic reference was made to natural composition of the substances used for the realization of the fixed points, except for helium. The definition of a reference isotopic composition for three fixed points, e-H2, Ne and H2O, while eliminating the non-uniqueness of the Scale in this respect, induced detectable differences in the present and future realizations of the Scale, at the highest accuracy level, with respect to the previous realizations, when they affected the results of past key comparisons, namely the K1 and K1.1, and K2 and K2.1 to K2.5 and the related regional and supplementary ones. The paper provides evidence of the extent of this effect by using the results of the relevant key comparisons for Neon archived in the BIPM KCDB, and of other comparisons existing in the literature: 1979-1984, 2007-2012 and 2009-2010 sealed cell comparisons; and discusses the meaning and the outcomes of this evaluation.

physics.data-an↗

arXiv2017

Improving the understandability of the next edition of the International System of Units (SI) by focusing on its conceptual structure

The International System of Units (SI) is fundamental for the social, and not only the scientific, role of metrology, and as such its understandability is a crucial issue. According to the current draft of the new SI Brochure, the next edition of the SI will be significantly more complex in its conceptual structure than the previous ones. Identifying a strategy for effectively communicating its main contents is then a worthwhile endeavor, in order to increase the acceptance and thus the sustainability of the SI itself. Our proposal is to focus on the semantic structure of the definitions: this is instrumental to the awareness campaigns recommended by the General Conference on Weights and Measures to make the next edition of the SI understandable by a diverse readership without compromising scientific rigor.

physics.ed-ph↗

arXiv2016

On the definition of the measurement unit for extreme quantity values: some considerations on the case of temperature and the kelvin scale

Many quantities are attributed a range of values that can apparently extend to infinity (on one side or both sides). In this respect, the definitions of their measurement units do not place any constraint to the maximum (or minimum) value for their validity. In general, that happens because those extreme values are far from being reached on the earth, or presently in experiments. However, since the same units are used also in fields of physics, chemistry or technology where they could occur, namely in the description of the universe in one sense, and in nano-scale or particle physics in another sense, the issue of extreme values (not in statistical meaning here) is not irrelevant. The question placed and discussed in this paper is whether the present kelvin scale, based on Lord Kelvin second definition (our currently accepted concept of temperature), applies over a full range between bounds (zero, infinite) or not, and about the concept of temperature in itself in the extremes regions. The aim, however, is not to provide an answer, but to suggest there are difficulties with the application of current concepts at extremes of temperature.

physics.gen-ph↗

arXiv2016

Comment to "Comment on 'Compositional and Microchemical Evidence of Piezonuclear Fission Reactions in Rock Specimens Subjected to Compression Tests' [Strain 47 (Suppl. 2), 282 (2011)]" by G. Amato et al

It is shown that the evidence asserted in the Comment [arXiv:1205.6418] on the chemical composition data published by Carpinteri et al. [Strain 47 (Suppl. 2), 282 (2011)]-that the data "cannot be the result of independent measurements as claimed by the authors" -may be not necessarily true. A simpler fact could explain the identical assay values found for some of the chemical components, without this implying the asserted impossible correlations. The simpler reason does not invalidate the published numerical data, being related only to incorrect notation. On the other hand, it is out the scope of the present comment implying any evaluation about the physical validity of the data or about the conclusions drawn in the original paper.

cond-mat.mtrl-sci↗