Evaluation of the uncertainty of coordinate measurements based on the formula for EL,MPE

The methodology of evaluating the uncertainty of coordinate measurements, developed at ATH (University of Bielsko-Biała) and verified within the EUCoM project, is presented, in which the only information about the accuracy of the CMM used is the formula for EL,MPE. The measurement models used for individual characteristics are derived from distance point-point, point-straight line, point-plane and straight line-straight line formulae. Information about the shape and dimensions of the measured workpiece is in the form of the minimum number of appropriately distributed points needed to define individual characteristics. The measurement model is a formula expressing the measured characteristics as a function of the differences in the coordinates of the characteristic points. The GUM uncertainty framework is used to propagate individual uncertainty components. Two models and example uncertainty budget is presented

Flow leaks renormalization

Flow leaks are small devices that generate a well-determined flow when subject to a pressure differential (feed pressure). Such devices are widely used in the industry for the easy generation of flows, which can be used for several applications. In order to be correctly included in a Quality Management System (QMS), they need to be calibrated against a reference flow. Such calibration depends on the feed pressure and on the fluid density through a complex relation which can be derived from the modified Darcy law, therefore results of a calibration performed in a given condition are not necessarily valid when the leak is used in different conditions (e.g. different atmospheric pressure, ambient temperature). In the present paper we will show how to obtain a correct renormalization of the calibration results, which, if applied in use, allows to compute precisely the actual flow rate generated by the leak. The renormalization is based on the modified Darcy law, and therefore requires the determination of the leak permeability. A mathematical description of the renormalization will be presented. Additionally, a method for the experimental determination of the permeability will be discussed The effect of the renormalization on the output of the leak will be demonstrated through a set of example cases, obtained in various environmental conditions within our laboratory. It will be shown that, first the calibration uncertainty can be reduced dramatically by applying the correct normalization, and second that the in-use uncertainty can be brought to be of the same order of magnitude as the calibration uncertaint

A novel calibration of the Large Piston Prover at INRIM

INRIM realizes its flow rate standard using three distinct facilities, aimed at measuring different flow rate ranges; in particular, for the larger flow range (10-2600 L/min) a piston of 1000 mm nominal diameter and 1200 mm nominal stroke is used. The traceability of the standard is obtained through dimensional calibration of the piston, regarding both the piston size and its stroke. The first calibration of the machine was performed at its initial installation. Even if most of the relevant documentation about this first calibration is not available, INRIM realized a procedure similar to the old one and performed measurements to renovate the first facility calibration. The present paper will dedicate special attention to the description of the measurement chain used for the calibration of the piston in its own siege. Moreover, the method for the transfer of traceability from the length standard to the measurement of the piston diameter will be discussed; it should be noted that the dimensional study is not completed yet, because the first set of measurements described in the present work, evidenced the criticalities of the procedure adopted in the past. For this aim, a further measurement campaign will be carried out in order to minimize the uncertainty associated to the dimensional measurement of the piston and of its displacement. Finally, the results of first dimensional evaluation will be presented alongside

Metrology for climate observation

As stated by GCOS “Long-term, high-quality and uninterrupted observations of the atmosphere, land and ocean are vital for all countries, as their economies and societies become increasingly affected by climate variability and change”. High-quality observation is possible only if based on a sustained traceability to SI and with documented uncertainties associated to the measured values. Following the signature of the MRA by the WMO , in April 2010, the CCT of the CIPM , in its XXV meeting of May 2010 submitted a recommendation to CIPM. The document highlighted the need to encourage National Metrology Institutes (NMIs) [...] to face new perspectives, needs, projects and activities related to the traceability, quality assurance, calibration procedures and definitions for those quantities involved in climate studies and meteorological observations and to support a strong cooperation between NMIs and Meteorological Institutions at local, national and international levels. In response to this call, several Joint Research Projects (JRPs) in metrology have been established. Their objective is to improve calibration procedures and measurement techniques for some Essential Climate Variables (ECVs), focussing especially on temperature, pressure and water vapour. Additional objectives have included investigations of sensor characteristics and the improvement of measurement devices and their use in the field. The impact effort is demonstrated also by the involvement of key international scientific Institutions such as GRUAN , ISTI , IAPWS , and prominent Manufacturers and Universities. The overall aim is to make a further step towards establishing full data comparability, consistency and long-term continuity, through a comprehensive evaluation of the measurement uncertainties for the quantities involved in the global climate observations. The improvement of quality of ECVs records, through the inclusion of measurement uncertainty budgets, will also highlight possible strategies for the reduction of the uncertainty. This contribution will report on JRPs advances, events and task group activities, with the vision to establish a permanent bridge between metrologists and climatologists, through which to strengthen and develop collaborations, joint activities/projects and results dissemination to the whole society

Civilización, masculinidad y superioridad racial: una aproximación al discurso republicano chileno durante la Guerra del Pacífico (1879-1884)

En este artículo se analiza el discurso republicano en el contexto de la Guerra del Pacífico. La propuesta es explicar cómo, por un lado, la noción de la "barbarie", tradicionalmente asociada a la naturaleza salvaje, fue empleada para referirse al despostimo, la degeneración y el lujo de la sociedad de Antiguo Régimen que - de acuerdo con los publicistas chilenos - aún reinaba en el Perú. La transformación del republicanismo, desde una ideología obsesionada con la fragilidad de la república a otra involucrada en la expansión territorial, permite estudiar el surgimiento de una "república imperio" en Chile. Esta reelaboración conceptual está basada en la austeridad, el trabajo arduo e incluso la incorporación de todos sus ciudadanos, incluyendo a los araucanos. Opino que el análisis de un experimento republicano llevado hasta sus extremos permitirá enriquecer el debate en torno a los vocabularios y a las prácticas políticas en la Hispanoamérica decimonónica

The MeteoMet project - metrology for meteorology: challenges and results

The study describes significant outcomes of the Metrology for Meteorology\u27 project, MeteoMet, which is an attempt to bridge the meteorological and metrological communities. The concept of traceability, an idea used in both fields but with a subtle difference in meaning, is at the heart of the project. For meteorology, a traceable measurement is the one that can be traced back to a particular instrument, time and location. From a metrological perspective, traceability further implies that the measurement can be traced back to a primary realization of the quantity being measured in terms of the base units of the International System of Units, the SI. These two perspectives reflect long-standing differences in culture and practice and this project - and this study - represents only the first step towards better communication between the two communities. The 3 year MeteoMet project was funded by the European Metrology Research Program (EMRP) and involved 18 European National Metrological Institutes, 3 universities and 35 collaborating stakeholders including national meteorology organizations, research institutes, universities, associations and instrument companies. The project brought a metrological perspective to several long-standing measurement problems in meteorology and climatology, varying from conventional ground-based measurements to those made in the upper atmosphere. It included development and testing of novel instrumentation as well as improved calibration procedures and facilities, instrument intercomparison under realistic conditions and best practice dissemination. Additionally, the validation of historical temperature data series with respect to measurement uncertainties and a methodology for recalculation of the values were included