Papers by salvatore lorefice
BIPM Membership of the Consultative Committees of the CIPM CC (EM-PR-T-L-TF-RI-U-M-QM-AUV)
La misura della viscosità con i viscosimetri a capillare
Metrologia, 2017
Evaluation of different types of comparisons to a common set of reference values of a CIPM key co... more Evaluation of different types of comparisons to a common set of reference values of a CIPM key comparison is essential to satisfy the concept of the CIPM Mutual Recognition Arrangement (CIPM MRA), where the DoEs of any participant who took part in comparisons should be within the Calibration and Measurement Capability (CMC) section of the CIPM MRA Key Comparison Data Base. The subject of this supplementary report is therefore to present the equivalence of each National Metrological Institute (NMI) participant in the CCM.D-K4 'Hydrometer' key comparison, which was performed in the density range 600 kg/m3 to 2000 kg/m3 at the temperature of 20 °C, and the linkage of the European and Inter-American NMI results performed in the RMO.M.D-K4 comparisons as well as those of the supplementary SIM.M.D-S2 to the common set of KCRVs of the CCM.D-K4 'Hydrometer'. The linking procedure has been obtained by numerical simulation, based on the Monte Carlo method, in which the differe...
Measurement, Dec 1, 2017
A method to conform the results of different type of comparisons to a common set of Reference Val... more A method to conform the results of different type of comparisons to a common set of Reference Values of a CIPM Key Comparison, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA), is the subject of this paper. In particular, the method has been applied for analyzing and making conform both petal results and the subsets of the European and Inter-American results of the RMO.M.D-K4 comparisons to the common set of KCRVs of the CCM.D-K4 "Hydrometer", which was performed in the density range 600 kg/m 3 to 2000 kg/m 3 , at the temperature of 20 °C. Basically, the subset of the "theoretical" degrees of equivalence DoEs with respect to the common set of KCRVs of CCM.D-K4 "Hydrometer" of any NMI laboratory, who didn't take part into both petals (groups A and B) of the CCM key comparison, has been obtained by numerical simulation, based on Monte Carlo method, in which the differences in the results of the different comparison between the intended laboratory and one or more linking laboratory/ies, which took part in both comparisons, are correlated with a continuous function describing the behaviour of the DoEs of the linking laboratory/ies with respect to the common set of KCRVs of the CCM.D-K4. The proposed linking procedure has clearly proved to work well by some practical linking examples which differ by each other from the number of linking involved laboratories as well as number of the tested points in the density range, allowing to evaluate the capabilities, through the DoEs, to be listed within the Calibration and Measurement Capability (CMC) section of the CIPM MRA Key Comparison Data Base for any participant who took part in comparisons and to give evidence of the comparability between institutes that could have not participated in all the exercises.
−This article reports the calibration procedure for a commercial Solartron 7835 densimeter which ... more −This article reports the calibration procedure for a commercial Solartron 7835 densimeter which is currently used as “reference” instrument in an automatic apparatus for the calibration of on-line densimeters. Three different materials (fluids), whose densities are known at the usual working condition of pressure and temperature, are used for characterizing the reference densimeter. The procedure applied at the INRIM to produce accurate parameter estimates in the densimeter calibrations is described in this papers. It is based on the application of the weighted least square method (WLS), considering together with the uncertainties of the dependent and independent variables also those of the model. The model analysis performed by a Chi-square test and the expected uncertainty computed over the calibration range have shown to be fully consistent with the experimental data.
Measurement, 2017
The base for all viscosity measurements is the internationally accepted viscosity of double-disti... more The base for all viscosity measurements is the internationally accepted viscosity of double-distilled water at 20°C. Using this water and liquids of ever greater viscosity, INRiM derives by a step-up procedure the constants for its master "glass capillary" Ubbelohde viscometers, and these are used in their turn to determine the viscosity of undetermined liquids and reference materials in the kinematic viscosities range from about 0.4 mm 2 /s to above 700,000 mm 2 /s with temperatures from 10°C to 150°C. From the results obtained on recalibration of the INRiM viscometers and the comparisons made with other independent laboratories, it is concluded that the present scale is realized with an uncertainty of about 0.2% at low viscosities rising to about 0.8% at high viscosities. This enable INRiM to provide traceability to Italian viscosity measurements as well as calibrating various types of viscometers for the highest measurement accuracy i.e. glass capillary, cups, rotational. This paper addresses the relevant procedure on the realisation of the Italian kinematic viscosity scale (viscosity standard) which was conducted over a number of years. The different sources of error in the viscometer calibration, mainly due to the contribution by the kinetic energy of the fluid stream, surface tension variations and, finally, buoyancy are considered. Special emphasis is also given on the uncertainty evaluation and in the international activities which provide evidence of the present measurement capabilities of the Italian laboratory and ensures smaller measurement uncertainties in the future.
Draft EUROMET Project 236. Technical programme. Intercomparison of a hydrometer calibration station by means of transfer standard hydrometers
SIGLEITItal
Substitution Method for Liquid Density Measurements by Vibrating Tube Densimeter
NCSL International Workshop & Symposium Conference Proceedings 2015, 2015
The improvement of modern oscillation-type density meters requires density reference liquids with... more The improvement of modern oscillation-type density meters requires density reference liquids with low uncertainty and very accurate procedures that take into account the physical properties of the fluids. INRIM adopted a procedure concerning the substitution method in determining the densities by vibrating tube densimeter of deuterated water, n-pentadecane and the oil EF 170 having a viscosity of approximately 170 mm²/s, liquids provided by the pilot laboratory BEV as transfer standards in the EURAMET project 1240. In the present paper are shown as an example about the validity of the used procedure through the results of the density determinations at 20 °C of the deuterated water and of the viscous oil, being the differences of the physical properties of the two liquids significant enough
Metrological assurance of viscosity measurements
Measurement, 1998
ABSTRACT This paper describes the metrological research and dissemination work carried out in the... more ABSTRACT This paper describes the metrological research and dissemination work carried out in the viscosity field at the Istituto di Metrologia “G. Colonnetti” (IMGC) of the National Research Council of Italy, which is responsible for national standards of mechanical and temperature units. Emphasis is given to the viscosity standard, to the latest research work concerning certain liquids to be used as reference viscosity standards, and to international activities.
Measurement, 2009
Laboratories must ensure that obtained results are reliable, for that it is necessary to calibrat... more Laboratories must ensure that obtained results are reliable, for that it is necessary to calibrate glassware and proving tanks using the correct method and estimate of uncertainties. The aim of this work is to present the gravimetric method as a suitable and traceable method to calibrate glassware according to laboratory requirements. Moreover, the model for the calculation of the measurement uncertainty is described and it is proved to be completely suitable for the calibration by gravimetric method through a numerical example drawn from the INRIM uncertainty budget in the CCM.FF-K4 key comparison.
Cryogenics, 1987
A turbine flowmeter with no mechanical contact between rotor and body is described, to be used as... more A turbine flowmeter with no mechanical contact between rotor and body is described, to be used as a reference standard in our liquid helium flow rate calibration facility. The absence of contact, zeroing the bearings friction factor, ensures a good measurement repeatability, even at very low liquid helium flow rate values. The rotor is magnetically suspended by the Meissner effect: at liquid helium temperatures two magnetic fields generate sustaining forces against the surface of the two rotor ends, which are made of niobium. Due to the repulsive nature of the acting forces, the rotor equilibrium is intrinsically stable and no external electronics are required for its levitation. A particular configuration of the superconducting windings and of the rotor ends allow the rotor to levitate and hold good axial and radial stability. A detailed description of the solutions adopted for the realization of the prototype and the operation conditions are reported. The first results, made with the absolute liquid helium calibration facility, are shown.
Cryogenics, 1987
Within the framework of a National Project on superconductivity two facilities have been designed... more Within the framework of a National Project on superconductivity two facilities have been designed and built at the Istituto di Metrologia 'G. Colonnetti' (IMGC) with the purpose of studying and calibrating liquid helium flowmeters in the range 1-20 g s-~ of liquid helium (LHe). After a brief description of these setups , this Paper examines in detail the solutions adopted in the design of the main calibration facility, particularly with regard to the circulating pump and the submerged driving motor. The latter has been devised for working only at LHe temperature, having an a.c. three-phase stator winding made of thin superconducting wire. The construction characteristics and operation conditions are discussed. As a flow rate reference, a new turbine flowmeter with its rotor magnetically suspended by the Meissner effect (described in another paper presented at the workshop), is used. A LHe flow rate transducer, based upon the measurement of the transit time of short thermal pulses, has been designed and tested with these facilities: the good results obtained using commercial low cost diodes as A T sensors are reported.
Measurement, 2010
Density measurements are frequently associated to specific requirements to evaluate the quality o... more Density measurements are frequently associated to specific requirements to evaluate the quality of a process or to determine mass and/or volume of the material. Certified reference liquids can be used to assure metrological traceability of density measurements to the SI with uncertainty lower than 0.005%. This paper presents the new approach of INRIM to set density standards. The procedure involved accurate density determinations of some reference liquids which were supported by gas-chromatography coupled with mass spectrometry (GC-MS) in order to assess their homogeneity and short-term stability. GC-MS analyses on tetrachloroethylene and trichloroethylene were carried out before and after density measurements. Samples that had undergone to variations in density value showed also different gas-chromatographic profiles. In the same time, samples that had not undergone to density variations kept similar gas-chromatographic profiles. The results support the approach of combining independent methods in order to set physico-chemical properties of reference materials.
Draft B- Report of the Bilateral Comparison of the Calibrations of Hydrometers for Liquid Density Determination Between Cenam
Hydrometers are instruments usually made of glass that are widely used for different levels of pr... more Hydrometers are instruments usually made of glass that are widely used for different levels of precision to measure density, specific gravity, alcoholic strength, sugar concentration, milk density, etc., of a liquid.
Exchange of Experiences Between Inrim and Ipq in the Density Field
Abstract- Density measurements are frequently associated to specific requirements in order to eva... more Abstract- Density measurements are frequently associated to specific requirements in order to evaluate the quality of a process or to determine mass and/or volume of the material. Hydrostatic weighing is the usual method to get directly the traceability to the SI system of the density as well as of the solid volume. INRIM (the former CNR- IMGC) supplied to IPQ a hydrostatic apparatus with a measuring cell, devoted to measure the density of liquids and the volume (density) of small solid bodies, with technical support and assistance in the density field. Since 2005 the partnership between the two Institutes has been developed within the EUROMET project 858 “Hydrostatic weighing – exchange of experiences”. This paper deals with the activity concerning the main technical and metrological characteristics of the supplied measuring cell and also shows the preliminary results for testing it. For this purpose a comparison was carried out between the two laboratories. Each one determined the...
Density measurements are frequently associated to specific requirements in order to evaluate the ... more Density measurements are frequently associated to specific requirements in order to evaluate the quality of a process or to determine mass and/or volume of the material. Hydrostatic weighing is the usual method to get directly the traceability to the SI system of the density as well as of the solid volume. INRIM (the former CNR IMGC) supplied to IPQ a hydrostatic apparatus with a measuring cell, devoted to measure the density of liquids and the volume (density) of small solid bodies, with technical support and assistance in the density field. Since 2005 the partnership between the two Institutes has been developed within the EUROMET project 858 “Hydrostatic weighing – exchange of experiences”. This paper deals with the activity concerning the main technical and metrological characteristics of the supplied measuring cell and also shows the preliminary results for testing it. For this purpose a comparison was carried out between the two laboratories. Each one determined the volume and...
HYDROSTATIC WEIGHING SYSTEM AT THE INRiM FOR CALIBRATINGHYDROMETERS
Hydrometers are simple but effective instruments for measuring the density of liquids. In this wo... more Hydrometers are simple but effective instruments for measuring the density of liquids. In this work, we present the new hydrostatic weighing system developed at the INRiM, formerly IMGC – CNR, for the calibration of hydrometers in the range 500 kg.m-3 to 2000 kg.m-3. The apparatus which uses a method to automatically align specific scale-marks for the calibration of hydrometers, makes easy the whole calibration procedure and allows to reduce the former uncertainty declared by laboratory. It consists of a vision system, a stepping motor, and software to control the system. The vision system, composed of a CCD camera and a frame grabber, is used to acquire images. The overall performance of the apparatus is illustrated by the assessment of the uncertainty for some usual kinds of hydrometers sent to the Institute for calibration.
Density measurements are frequently associated to specific requirements in order to evaluate the ... more Density measurements are frequently associated to specific requirements in order to evaluate the quality of a process or to determine mass and/or volume of the material. Certified reference liquids can be used to assure metrological traceability of density measurements to the International System of Units (SI) with uncertainty lower than 0.005 %. This paper presents the new approach of the Italian Istituto Nazionale di Ricerca Metrologica (INRIM) to set density standards. The procedure involved accurate density determinations of some liquid samples, to be used as references, on which in addition analysis by means of gas-chromatography coupled with mass spectrometry (GC-MS) was performed to support homogeneity and short-term stability. In this exercise GC-MS analyses on two chlorinated liquids (namely tetrachloroethylene and trichloroethylene) were carried out before and after density measurements. The results obtained with the two different techniques were encouraging. Samples that ...
Key comparison of liquid density standards
At the SIM meeting in Buenos Aires, from 30 May to 1 June 2012, it was decided a RMO key comparis... more At the SIM meeting in Buenos Aires, from 30 May to 1 June 2012, it was decided a RMO key comparison on pH measurement coordinated by INMETRO would be performed, named SIM.QM-K91, in order to investigate the degrees of equivalence of measurement procedures for the pH determination of a phthalate buffer solution (nominal pH around 4.01 at 25 °C). Phthalate buffer is widely used to calibrate pH electrodes in the acid range. A buffer solution of 0.05 mol kg-1 potassium hydrogen phthalate, KHC8H4O4, is one of the primary pH reference buffer solutions recommended by IUPAC. It was only allowed to participate in this comparison by using a differential cell or a glass electrode, instead of primary cells, if the highest metrological standard in the institute or if the CMCs are based on the type of cell to be used. The results obtained by INMETRO and NIST (who also participated in CCQM-K91 comparison) were used to link the results from the other institutes to the key comparison reference value...
CCM.V-K3: CCM Key Comparison of Viscosity
Metrologia
This report describes the third CCM key comparison in capillary viscometry at twelve National Met... more This report describes the third CCM key comparison in capillary viscometry at twelve National Metrology Institutes (NMIs), which was carried out between October 2012 and February 2013. Seven NMIs, which do not maintain an independent viscosity scale, also took part in this comparison. Three samples of Newtonian liquids with nominal kinematic viscosities of 6 mm²/s at 15 °C and 5 mm²/s at 20 °C, 2000 mm²/s at 20 °C and 500 mm²/s at 40 °C, and 160000 mm²/s at 20 °C and 25000 mm²/s at 40 °C prepared by NMIJ were provided to each of the NMIs. For each of these liquids at two temperatures, total number of 98 measurements was carried out and from the results of viscosity measurements, the key comparison reference values (KCRVs) for six data sets were determined. The degrees of equivalences was evaluated by difference from the KCRV and, with a few exceptions, these differences were almost equal to or less than expanded uncertainties, showing a good equivalencies of capabilities at the part...
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Papers by salvatore lorefice