Monthly Archives: August 2015

Comparing Approaches to the Description of Nanomaterials

This post comes from John Rumble, chair of the CODATA Working Group on the Description of Nanomaterials, and Egon Willighagen, of Maastricht University and the eNanoMapper Project.

UDS CoverThe CODATA Working Group (WG) on Nanomaterials held a small workshop with members of the eNanoMapper (  team at Maastricht University in the Netherlands, on 13-14 July, 2015. The purpose of the meeting was to clarify and compare approaches to the description of nanomaterials, specifically the  CODATA WG’s Uniform Description System for Materials on the Nanoscale  (UDS) ( and the eNanoMapper Ontology, as  described in Journal of Biomedical Semantics (2015) (

At the workshop, all major UDS information categories, subcategories, and descriptors were reviewed in detailed and compared to the eNanoMapper ontology. Several issues were identified as requiring revision, including better description of measurement methods used to characterize aspects such as size, shape, and size distribution, the role of topology, and differentiating among different types of nanomaterial stability. The results of this workshop will be combined with recommendations made at a similar workshop held at the Universities at Shady Grove in the United States on10-11 June 2015, to guide revision of version 1.0 of the UDS. The next version should be available in early September and will include downloadable tables and sources of definitions, when applicable.

s13326-015-0005-5-2Immediately following the Maastricht workshop, CODATA WG representatives met at the Quality Nano Conference held in Crete. Of particular interest was the description of coatings and coronas for individual nano-objects, especially with respect to their reproducibility (or randomness) and predictability.

For further information about the CODATA Nanomaterials WG, please contact John Rumble at For further information about eNanoMapper, please contact Egon Willighagen at

Climate Change is everyone’s responsability: we need community initiatives

This post is by Elizabeth Griffin, chair of the CODATA Data at Risk Task Group, and co-chair of the related RDA Interest Group on Data Rescue.

ocfcc_paris_2015An international conference on Our Common Future under Climate Change in Paris? A remarkable choice of venue as it turned out: climate change was pronounced, the temperature swinging from 39ºC to 21ºC faster than you could keep track, while the freshness and friskiness of the wind suggested autumn in early July. Longer-term aspects of the changes, those insidious underlying trends that we only perceive by reference to accurate past data, demanded the busy attention of some 2000 delegates from all over, their specialities and contributions disaggregated into some 165 parallel sessions classified according to their bearings on data, interpretations, or solutions.

Gems were admixed with frustrations. The jewelry to be gained by connecting disparate strands was tarnished by their division into so many parallel sessions that some deserving nuggets had to glister unseen, limiting the effectiveness of each message. The delegates had messages enough – the list of session titles and contents were ample witness to that – but giving each space by subdividing the sessions where no division was obvious or suitable did not serve the speakers well. Neither did dividing the conference physically between three locations that took 15-20 minutes of healthy street walking or less-healthy metro riding – presumably inevitable for reasons of available space, but not ideal from the aspect of the conference. Any venture outside was as good as a continent away, and must have deterred many.

What did we hear that was novel, unexpected, heart-warming or frightening? Plenty in all categories. The evidence of climate change, particularly in the polar regions, is incontestable to any but the deliberately blind, though interpretations are too model-dependent to represent the cast-iron situation that politicians seem to need. Heart-warming were the intimate projects, evidenced in numerous posters, describing heroic local efforts to challenge what the world now threatens them with. Even gender seemed to play a convincing role in countries like Bangladesh, where women have little control over the deployment of resources.

But the many theoretical solutions for “reducing carbon emissions” through science-based policies and managed economies were neither novel nor unexpected, and none tackled adequately the fundamental question: Who or what can be defined as responsible for actually driving AND SUSTAINING climate change? If the correct answer is (as I interjected) Everyone, then that is where solutions must begin. But why did the solution thus stated appear so radical that it merited recording for use in students’ summer school on climate change? Are the emperor’s new clothes really so hard to see?

Transition Town Totnes

How can that message get to where it is certainly needed but still blithely ignored? Some hypocrisy was on evidence at the conference: lunch came in modular plastic cups destined for a landfill, and the registration fee included items we neither needed nor wanted. Is the future something that “civilized” humanity would rather give into than face? Is all this just a theoretical exercise, always someone else’s problem?

Transition Town Totnes

Time is running out. Tipping-point is approaching. Tomorrow is nearly here. But there is hope – the psychology of Community can break the vicious circle when moral issues are introduced into the solution, such as in Transition Towns like Totnes (UK) and mini-eco communes (e.g., in Cornwall, UK). The nuggets of excellence and example created by local communities will become the jewels of our own future provided that (a) we manage them effectively, and (b) we start acting now.

CODATA Recommended Values of the Fundamental Physical Constants: 2014

This post comes from David Newell, Chair of the CODATA Task Group on Fundamental Physical Constants.  See also:

The compilation of the 2014 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use has recently been completed by its Task Group on Fundamental Constants (TGFC). The new values are available from ArXiv arXiv:1507.07956v1, from the CODATA Zenodo Collection and from the NIST website on ‘Constants’ Units and Uncertainty’  They are based on a multi-variant least-squares adjustment that takes into account all data available through 31 December 2014.

Table 1-CODATA Recommended Values of Fundamental Physical Constants 2014

As a working principle, the validity of the physical theory underlying the adjustment is assumed. This includes special relativity, quantum mechanics, quantum electrodynamics (QED), the standard model of particle physics, including CPT invariance, and the exactness of the relationships between the Josephson and von Klitzing constants KJ and RK and the Planck constant h and elementary charge e. Although the possible time variation of the constants continues to be an active field of both experimental and theoretical research, to date there has been no confirmed observation of a variation relevant to the data on which the 2014 recommended values are based.

2014 Values: Reduction in Uncertainty

A significant number of new results became available for consideration, both experimental and theoretical, from 1 January 2010, after the closing date of the 2010 adjustment, through 31 December 2014, the closing date of the 2014 adjustment. Overall, the recommended values fundamental constants have become more accurate, i.e., their uncertainties have decreased, due to improved measurements and theoretical calculations of the measurable quantities that depend on the constants. For example, compared to the CODATA 2010 recommended values,

  • The 2014 value of the relative mass of the electron Ar(e) has a relative uncertainty of 2.9 × 10‑11, a reduction in uncertainty by a factor of 14.
  • The 2014 value of the fine-structure constant a has a relative uncertainty of 2.3 × 10‑10, a reduction by a factor of 1.4.
  • The 2014 value of the Newtonian constant of gravitation G has a relative uncertainty of 4.7 × 10‑5, a reduction by a factor of 4.7.
  • The 2014 value of the Planck constant h has a relative uncertainty of 1.2 × 10‑8, a reduction by a factor of 3.7.
  • The 2014 value of the Boltzmann constant k has a relative uncertainty of 5.7 × 10‑7, a reduction by a factor of 1.6.

Challenges with Input Data for the Proton RMS Electric Charge Radius rp

As is the case with all CODATA adjustments of the fundamental physical constants, a major challenge is the treatment of discrepant input data. For the 2014 adjustment the input data for the proton root-mean-square (rms) electric charge radius rp remained a puzzle. The value of rp from muonic hydrogen experiments has a smaller uncertainty by more than a factor of 10 than that from a combined value of rp from electron-proton scattering data and hydrogen (H) and deuterium (D) spectroscopy, yet differs by over a factor of five times the uncertainty of their difference, or “5σ”. To address this discrepancy, the TGFC invited the principle investigators and experts involved with the experiments and theory related to muonic hydrogen, electron-proton scattering, and H and D spectroscopy to its 2014 meeting held 3-4 November 2014 at the International Bureau of Weights and Measures (BIPM). Based on the advice of these experts, it was decided not to include the muonic hydrogen results in the 2014 adjustment (see details and minutes of the November 2014 meeting). To help address other input-data issues, CODATA co-organized a workshop 1-6 February 2015 in Eltville, Germany where various issues with the analysis of the electron-proton scattering data as well as with some of the acoustic gas thermometry data were resolved (see

2018 CODATA Recommended Values and the New SI

CODATA is presently preparing for its major role in a significant revision of the International System of Units (SI) scheduled for adoption in the fourth quarter of 2018. This “New SI” will be based on exact numerical values for h, e , the Boltzmann constant k, and the Avogadro constant NA (for more information, see:   In 2011 at its 24th meeting the General Conference on Weights and Measures (CGPM) invited CODATA to continue to provide least-squares adjusted, recommended values of the fundamental constants, h, e, k, and NA in particular, since these values will be those used for the revised SI. Because of the good progress made in both experiment and theory since the 31 December 2010 closing date of the 2010 CODATA adjustment, the uncertainties of the 2014 recommended values of h, e, k and NA are already at the level required for the adoption of the revised SI by the 26th CGPM in the fall of 2018. The formal road map to redefinition includes a special CODATA adjustment of the fundamental constants with a closing date for new data of 1 July 2017 in order to determine the exact numerical values of h, e, k, and NA that will be used to define the New SI. A second CODATA adjustment with a closing date of 1 July 2018 will be carried out so that a complete set of recommended values consistent with the New SI will be available when it is formally adopted by the 26th CGPM. Ordinarily the closing date for the regularly scheduled CODATA adjustment carried out every four years―in this case the 2018 CODATA adjustment―would have been 31 December 2018. However, the normal date has been advanced by six months so that the 2018 set of CODATA recommended values will not only be consistent with the New SI, but ready for all to use at the exact same time the New SI becomes a reality.