Science and engineering research excellence can be maximized if the selection of researchers is made from 100% of the pool of human talent. This requires policies and approaches that encourage broad sections of society, including women and other underrepresented groups, to participate in research. Institutional policies, interpersonal interactions, and individuals’ attitudes are drivers of workplace culture. Here, some new evidence-based and systematic approaches with a focus on culture are proposed to foster women’s inclusion and success in science and engineering.

This Key Comparison of gauge blocks (GB) calibration by optical interferometry was carried out to support this Calibration and Measurement Capability (CMC) of the National Measurement Institutes (NMI) from the SIM Region for this specific service and for those that rely on this kind of technique as required by the Mutual Recognition Arrangement (MRA). It provides evidence of the participant's technical competence and supports the uncertainties they state in their CMC. It is a Regional Key Comparison and should be linked to the upper level corresponding comparison CCL-K1. The comparison had nine participants, five from the SIM Region—NRC-CNRC, Canada; NIST, USA; CENAM, Mexico; INMETRO, Brazil; and INTI, Argentina— and four from other regions—CMI, Czech Rep.; CEM, Spain; NPLI, India; and NMISA South Africa. It included the circulation of fourteen GB—seven steel GB and seven ceramic GB. The circulation of the artifacts started on 2007-11-01 and ended on 2010-04-25. Some additional time was required to publish the results as the same artifacts were used thereafter for comparison SIM.L-S6, Calibration of GB by mechanical comparison, and the results could not be disclosed until the participants of the second circulation loop had sent their results. The final report of this comparison was sent out for review in May 2012 and the final version was approved in August 2012. The behavior of the artifacts throughout the circulation was good and therefore the results obtained were judged technically valid. The reference value was taken as arithmetic mean of the largest subset of consistent results. Most of participates obtained results in good agreement with the reference values with a few exceptions mentioned in the report. The corresponding NMIs are responsible for identifying the causes and taking corrective action. This makes the present comparison exercise valid to support the CMC claims of the participants in GB calibration by optical interferometry. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Nanotechnology is generally defined as the study, exploitation and/or manipulation of matter with size range from approximately 1 to 100 nm. The focus of nanotechnology is largely on the new and novel properties and/or functionalities of traditional substances when they have structures of nano-scale dimensions. Science continues to push frontiers of knowledge, and the transformation of science into technology is underpinned by profound understanding and predictive models, which can only be attained via measurement results which are widely reliable and comparable. Therefore, measurement science and metrology are essential for nanoscale manufacturing of new materials, devices and products.

Measurement of grating pitch by optical diffraction is one of the few methods currently available for establishing traceability to the definition of the meter on the nanoscale; therefore, understanding all aspects of the measurement is imperative for accurate dissemination of the SI meter. A method for evaluating the component of measurement uncertainty associated with coherent scattering in the diffractometer instrument is presented. The model equation for grating pitch calibration by optical diffraction is an example where Monte Carlo (MC) methods can vastly simplify evaluation of measurement uncertainty. This paper includes discussion of the practical aspects of implementing MC methods for evaluation of measurement uncertainty in grating pitch calibration by diffraction. Downloadable open-source software is demonstrated.

A method for the evaluation of international comparison results is demonstrated by consideration of the CCL-K2 key comparison of long gauge block calibration. CCL-K2 is selected for this illustrative example because the comparison measurand is a geometrically simple case of the gauge block central length, and challenging measurement issues often encountered in international comparison exercises are present and can be discussed.

The full suite of tools for the evaluation of statistical consistency of metrological data is applied to the data set compiled from two recent international comparisons: CCT-K7 and EURAMET.T-K7. This paper illustrates how insights into lab measurement characteristics such as repeatability, reproducibility, secular uncertainties and laboratory equivalence statements can be obtained in a statistically-rigorous manner.

Harmonized sample pre-treatment is an essential first step in ensuring quality of measurements as regards repeatability, interlaboratory reproducibility and commutability. The development of standard preparation methods for single-wall carbon nanotube (SWCNT) samples is therefore essential to progress in their investigation and eventual commercialization. Here, descriptions of sample preparation and pre-treatment for the physicochemical characterization of SWCNTs are provided. Analytical methods of these protocols include scanning electron microscopy (dry, wet), transmission electron microscopy (dry, wet), atomic force microscopy, inductively coupled plasma mass spectrometry, neutron activation analysis, Raman spectroscopy (dry, wet), UV-Vis-NIR absorption and photoluminescence spectroscopy, manometric isothermal gas adsorption and thermogravimetric analysis. Although sample preparation refers to these specific methods, application to other methods for measurement and characterization of SWCNTs can be envisioned.

This paper reports results of an international comparison of one-dimensional (1D) grating pitch calibration by optical diffraction. Comparison results are analysed and discussed following the recommended guidelines for the analysis of CIPM key comparisons. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Nanotechnology emerges out of fundamental science through capability for accurate, repeatable and reproducible measurements on the nanoscale which allows scientists and engineers to accumulate knowledge. Understanding the measurement science is the first step towards development of new ideas. This paper describes some research initiatives which underpin the development of nanotechnology. Programs underway at the National Research Council of Canada include: development of metrological scanning-probe microscope instrumentation for dimensional calibration, materials characterization, development of artefacts designed specifically for dimensional calibration, investigation of metrology for application to soft materials and investigation of intrinsic length standards for realization of the SI metre at the nanoscale.

A model equation is developed for a diffractometer operating under the Littrow condition. The effects of grating orientation, grating position, source and detector position and source collimation are included. The model is validated against experimental measurements using the NRC imaging diffractometer. Errors due to the effects of coherence and grating position were found to be important for the small area gratings used in these experiments. An uncertainty budget for the NRC imaging diffractometer is developed and reproducibility measurements are presented.

Supplement 1 to the ISO Guide to the Expression of Uncertainty in Measurement ( GUM) outlines the application of Monte Carlo ( MC) simulation to uncertainty propagation through the mathematical model of the measurement. The MC approach uses the information contained in the probability density functions associated with each of the influence parameters of the measurement to determine the probability density function of the output quantity. This paper discusses an approach to uncertainty evaluation for calibration of line scales amenable for application of MC methods. The model for the measurement uncertainty in line scale calibration is interpreted from the perspective of the line-scale user, namely a distance measurement between any two intervals of the line scale. For this purpose, the introduction of a consensus invariant assigned in an alternative interpretation of the data can also expedite international comparison analysis. The proposed method is illustrated using a practical real-world example from an international comparison of calibration of line scales.

This paper presents a detailed measurement uncertainty analysis for the calibration of gauge blocks made from like materials using a mechanical comparator consisting of opposing styli and a digital readout. After discussing the influence parameters affecting the calibration process, a mathematical model is developed that leads to a measurement equation relating the length of the client's gauge block to measurements of the standard gauge block and associated temperature corrections. Following the ISO “Guide to the Expression of Uncertainty in Measurement,” all of the uncertainty components and their sensitivity components are calculated. These components include factors related to the calibration of the standard, the measured difference between the client's gauge and the standard gauges, and various temperature differences. After discussing a specific measurement process in a typical laboratory environment, all of the uncertainty components are quantified and then combined in quadrature. The resul...

A generalized formalism is presented for linking a Comite International de Poids et Mesures ( CIPM) key comparison ( KC) with similar regional KCs. The mechanism proposed provides a straightforward and practical means for reporting on the equivalence of the larger ensemble of national metrology institutes resulting from the linking of a regional metrology organization KC to the CIPM KC of the same measurand. Redundancy in the linking path which results when there is more than one linking lab is exploited for testing the statistical consistency of the linking relative to the claimed uncertainties. The proposed linking procedure is described and illustrated with a real-world practical example employing extended chi-squared-like statistics. A procedure for linking in the presence of artefact drift or other parametrized corrections is outlined.

The Consultative Committee for Length (CCL) has recommended that red (633 nm) unstabilized helium-neon lasers, operating on the 3s(2) -> 2p(4) transition, should be included in the list of standard frequencies for realization of the metre. This paper discusses several topics relating to the recommendation: motivations for including an unstabilized laser in the list of standard frequencies, considerations in assigning a value and an uncertainty for the frequency and vacuum wavelength of the 633 nm transition, and problems associated with the possible presence of 640 nm radiation in the laser output. The fractional uncertainty assigned to the vacuum wavelength of the 633 nm transition is 1.5 x 10(-6) (relative standard uncertainty). This uncertainty is sufficiently large to capture all sources of variability associated with construction or operating details of the laser and variations in isotopic mix that might be encountered in commercial laser tubes.

A laser diffractometer for calibrating grating pitch is being developed at the National Research Council (NRC). Based on the METAS design, it features a precision rotary table, the sample grating mounted in Littrow configuration, a collimated spatially filtered laser source and the retroreflected diffraction order sent by a beamsplitter through a focusing lens to the null-position photodetector. The angle of various diffraction orders can be measured in sequence and used with knowledge of the laser wavelength to calculate the pitch of the grating. Instead of the usual quad-photodetector, the NRC system uses a charge-coupled device (CCD) video camera to capture an image of the diffraction pattern. Image processing accurately measures diffraction order centroid coordinates without a systematic error due to background noise or neighbouring pattern artefacts. The image coordinate system is also used to adjust the instrument and grating alignment and to investigate these sources of systematic error. Preliminary results with 1D sample gratings ranging in pitch from 700 nm to 10 mu m are presented.

Results of the Stage One portion of the Inter-American System of Metrology (SIM) regional international comparison of gauge block calibration by optical interferometry are presented. In this measurement round-robin, short gauge blocks, six made of steel and six made of tungsten carbide, in the range of nominal length from 2 mm to 100 mm, were calibrated by five national metrology institutes (NMIs) of the SIM region, and one NMI from EUROMET. By employing the technique of optical interferometry, each of the laboratories establishes a direct link to their national primary standard of length through the calibrated laser wavelengths. Results of central length calibration are presented and discussed with regard to vacuum wavelength correction for refractive index of air, phase-change on re.ection and wringing effects. Measurement uncertainty evaluation is also discussed. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

A workshop on statistical techniques for evaluating key comparison data in length metrology was held as part of the September 2005 meetings of the Working Group on Dimensional Metrology of the Consultative Committee for Length (CCL) of the International Committee for Weights and Measures. This paper summarizes the discussion at this workshop and the resulting recommendations, subsequently adopted by the CCL, for evaluating future key comparison data in dimensional metrology. Motivation and supporting information relating to the recommendations are included.

The conclusions from international key comparison (KC) experiments constitute an important basis for validating the mutual recognition of measurement capabilities between the national metrology institutes (NMIs). Conventional χ (chi squared) methods for data analysis have been recommended in a move to promote uniformity in the conclusions drawn from KC results. Extended χ methods can address the complexities of degrees of freedom or novel algorithms for using peer results to select a reference value. In many situations, the utility of a KC reference value can be overstated. By focusing instead on pair differences, unmediated consistency analysis offers a better method for testing the statistical consistency of a KC data set. This paper discusses extended χ methods, using the mean-square of the normalized differences between pairs of measurements, or pairs of “consensus invariants” derived from the measurements. The underlying simplicity of comparing real measurements to each other (avoiding any equivocal approximation to “the right answer”) can reduce the perceived complexity of a KC experiment, particularly for KCs with multiple measurands that can all be incorporated into the χ average. An example from CCL.SIM-K1 is discussed.

The influence of gauge block preparation on their optical reflection properties is investigated. Results of length calibration experiments by optical interferometry performed on 9 steel gauge blocks having a wide range of surface roughness characteristics and pre-treatment are described. These data demonstrate that different conventional cleaning procedures and the use of appropriate wringing fluids have negligible effect on the reflection properties of the measurement surfaces of gauge blocks and platens.