Personnel: Researchers and Technologists: 24; Technicians: 25; Other technical and scientific personnel: 4; Graduate students: 2; Administrative personnel: 0.5

The Division is responsible for realizing, maintaining and disseminating the national standards of the SI units of mechanical quantities; it develops knowledge, technologies, competencies and capabilities in the field of mechanics, nanometrology and aerospace. The activity is focused on the following research programs:

• Mass measurements
• Dynamometry
• Fluid mechanics
• "Mise en pratique" of the metre and technologies for space
• Precision engineering

Some relevant data summarizing the Division are presented below.

The main results the Division obtained are related to Joint Research Projects of the iMERA-plus programme, covering coordinator capacity:

JRP NAh
-Avogadro and molar Planck constants for the redefinition of the kilogram (within the Target Programme "SI and Fundamental Constants"): in 2008, a key result was the realization of a guideway capable of displacements up to 5 cm with guiding errors meeting the requirement of atomic-scale positioning and alignment of an x-ray interferometer. This breakthrough extends by more than on order of magnitude the performances of any preceding measurement of unit-cell volume;

JRP-Nanotrace
-New Traceability Routes for Nanometrology (within the Target Programme "Length"): the aim is to improve by one order of magnitude the state of the art of optical interferometers for small distance measurements (goal: < 10 pm error over 100 µm). A heterodyne and a multipass homodyne interferometer having a resolution of 20 fm/√Hz have been realized.

The Division is also involved in other JRPs as a participant within the Target Programme "Length":

-Absolute long distance measurements in air: a relative incremental interferometer based on a heterodyne system was realized on a bench having a total range of 28 m: then the range was extended up to 84 m adopting a three-fold mirror system (used in 2008 to validate an interferometer for space applications it will be used for validating an absolute interferometer within a national Project);
-Traceable characterization of nanoparticles: an algorithm of image analysis was developed for the prototype of a scatterometer able to single out fibrous and spherical particles (≥10µm) in dynamic and static configurations;
-Metrology for New Industrial Measurement Technologies: development of software for testing SW according to EN ISO 10360-6 was addressed to the implementation of modules of the random generation engine, relevant to linear associated features (2D and 3D line, plane), a data generator for linear associated features and reference SW for linear associated features. The consistency of these last two was demonstrated.

In the regional project "Ultrastable Frequency References for Laser Interferometry in Space", aiming at the realization of a stable laser designed to withstand the huge launch loads, the prototype cavity (fig. 1) was acquired in 2008 and the frequency stabilization system was tested on an iodine-stabilized laser, obtaining a relative frequency stability better than 10^-11 (the goal being 10^-12) for time scale of 10⁴ s. The cavity is now being integrated in the system.

In order to evaluate the movement (position and orientation) of a robot, the Visual Odometry algorithm was reimplemented in real-time, and extensive field tests were carried out to characterize its accuracy. A landmark-based navigation algorithm for reducing the accumulated error on cyclic paths has also been implemented. To support the scientific activities great attention was focused on the study of new techniques of data analysis and their application to the evaluation of measurement uncertainties.

Permanent activities and periodic verifications to improve and maintain the standards were carried on. The main improvements are related to: the volume determination of mass standards by weighing, done in different air conditions, with the aim of eliminating the conventional weighing method and avoiding contamination of the standards; to perform reliable measurement of tiny gas flows for tightening tests, the gas flowmeter was improved to measure gas flow from leak artefacts delivered pertaining to atmospheric pressure lower then 5·10^-6 Pa·m³/s. N. 18 international comparisons are in progress. At the end of 2008 CMC entries published in the BIPM database were 164, during the year three new entries for liquid density were accepted and the CMCs for step gauge 400 mm, volumes of liquid and gas flow were confirmed. The division takes part in various international organisms: Consultative Committee for Mass and related quantities (CCM), Consultative Committee for Length (CCL) and the relevant working groups, Technical Committees of Mass, Length and Flow in EURAMET, IMEKO, CIRP and ISO normative organisms. At national level cooperation with universities, research institutes and the standardization body UNI were carried out.

Knowledge dissemination concerns different activities from publications of the scientific results to dissemination of competencies to enterprises. In this last field the results of the Division were:

a) patents, during the year two Italian patents were registered abroad: "Method for determining geometrical errors in a machine tool" and ",Spectrophotometer and spectrophotometric process using Fabry-Perot Resonator";
b) industrial contracts, two new contracts were drawn up in the aerospace field; the GEMIL (Geometrical Errors by Measurement of Independent Lines) contract was carried on, achieving an optimised experimental plan to determine the error components of CMM subject to rigid body behaviour;
c) standardisation: the extension of the concept of test uncertainty was extended from CMMs to all GPS measuring devices, and the leadership of a new international standard on this issue was assumed;
d) awareness initiatives: the CMM Club Italia, established and led by INRIM, scores 70+ members from industry and academia active in coordinate metrology;
e) measurement campaigns: the absolute gravimeter was used to measure free fall acceleration in different sites of the Republic of Panama and in the volcanic area of Etna.

The numbers of the Division for accreditation and calibration concern respectively 148 laboratories and 440 certificates. The results of the SIT comparisons to verify the performances of CMM and pressure balances in liquid medium with innovative analysis methodology were available.