franco pavese - Academia.edu (original) (raw)

Papers by franco pavese

In measurement science the object of a measurement is called “measurand”. It is defined in VIM:20... more In measurement science the object of a measurement is called “measurand”. It is defined in VIM:2012 clause 2.3 as “quantity intended to be measured” (but in GUM:1995, B.2.9 it is defined instead according to VIM:1993 clause 2.6 “particular quantity subject to measurement”. In VIM:2012, NOTE 1 to clause 2.3 specifies “the specification of a measurand requires … description [i.e., a model] of the state of the phenomenon, body, or substance”. The concept of measurand should be shared by the relevant Community, because the same measurand is supposed to be the object of replicated measures that must be comparable, i.e., it should be recognised as a quantity having a current recognisable meaning for the community. In the dialect of the science philosophers, this means that it should be projected into a “social framework”. Also in the scientific frame this means that the measurand model must be of the “prescriptive” type, meaning “giving directions or injunctions”— not always meaning “phys...

AIP Conference Proceedings, 2003

An overview of the main results of an international star intercomparison of low-temperature fixed... more An overview of the main results of an international star intercomparison of low-temperature fixed points is given. Between 1997 and 2002, 52 sealed triple-point cells (STPCs) of the thirteen laboratories represented by the authors have been investigated at PTB. The STPCs are used to realise the triple points of hydrogen, neon, oxygen, and argon, respectively, as defining fixed points of

Advances in Cryogenic Engineering, 1984

As in many other countries, attention was focussed in Italy recently on large-scale applications ... more As in many other countries, attention was focussed in Italy recently on large-scale applications of superconductivity. In 1978 a National Project on Applied Superconductivity was financed by the National Research Council (CNR), mainly centered on the design of a large superconducting generator, with some related experimental exercises on cryogenic technology and related problems. In the framework of this Project, the Istituto di Metrologia “G.Colonnetti” (IMGC) of the CNR was given the job to set up a facility for the characterization of the types of transducers involved in the operation of cryogenic machinery. In fact, the specifications of commercially available transducers were quite unsatisfactory (the situation has not improved much since then). of advanced cryogenic projects active around the world and the research and development on instrumentation that certainly had to be done by single industries or laboratories. Perhaps, this was due to the fact that results have a limited interest for other users, if accuracy in the characterization is limited or if information about the reliability (especially long-term) of the selected or newly studied devices is lacking.

Metrologia, 2014

ABSTRACT This note discusses some problems that should be taken into account in the implementatio... more ABSTRACT This note discusses some problems that should be taken into account in the implementation of the proposed use of fundamental constants in the definition of measurement units: use of CODATA adjusted values of the constants for this specific purpose; how the CODATA Task Group could continue performing meaningful least squares adjustments of the fundamental constants taking into account future data. Online Free at http://stacks.iop.org/0026-1394/51/L1

Measurement

Abstract The paper is an adjourned digest of critical features to be considered should the propos... more Abstract The paper is an adjourned digest of critical features to be considered should the proposed use of constants in the definition of measurement units of the SI be implemented: lack of a definitional realisation method; continuity requirement; individual base-unit definitions; possibility of future new determination of the numerical values of the constants; New SI hierarchy ladder. In addition, a critical review is presented of the text of the CCU 2016 Draft, Sections 1 and 2, of the 9th SI Brochure. Summary tables and a Glossary are included.

Advances in Cryogenic Engineering, 1978

The defining points of the International Practical Temperature Scale issued in 1968 (IPTS-68) [1]... more The defining points of the International Practical Temperature Scale issued in 1968 (IPTS-68) [1] involve five boiling points and three triple points from 13.81 to 273.15 K. Shortly after its adoption, the many fixed points involved in the new definition were found to be quite difficult to realize even for national laboratories; KOL, NPL, NRC, and PRMI* have only recently realized all the fixed points. In the course of the studies in these and other laboratories, the information on fixed points has greatly increased since 1968. Boiling-point temperatures appeared to be affected by impurities in the gas sample; thus, the dew point was sometimes preferred [2]. In addition, the measurement of pressure was necessary, and for some gases this had to be performed with a high degree of accuracy. At the same time, careful studies first made by Ancsin [3] showed that with a calorimetric method it was possible to obtain excellent results with triple points (t.p.); as a consequence, the triple point of argon (83.798 K) was introduced in the amended 1975 version of the IPTS-68 as an alternative to the normal boiling point (n.b.p.) of oxygen (90.188 K).

Advances in Cryogenic Engineering, 1998

Mechanical creep of the diaphragm is well recognized as a major problem for obtaining a reproduci... more Mechanical creep of the diaphragm is well recognized as a major problem for obtaining a reproducible cryogenic pressure transducer and it is mainly caused by the stress at the diaphragm edge, where this is rigidly constrained to the transducer body. The double-diaphragm design alleviates this problem. In this design, the rigid constraint of the diaphragm edge is replaced by a (non-ideal) hinge between two identical diaphragms, which allows for a considerable improvement of the reproducibility on thermal cycling. Sapphire has normally been used for this design because of its excellent elastic properties. However, the quality of the results critically depends on technological details of the fabrication.

Recent results in the development of resistance thermometers based on germanium films on gallium ... more Recent results in the development of resistance thermometers based on germanium films on gallium arsenide are summarized. Preliminary results in the development of a new generation of radiation-resistant thermometers and multifunction sensors intended for use in the range 0.03 to 500 K in the presence of high magnetic fields are discussed. These sensors have been produced in an international collaboration recently funded through the EU INTAS program.

This paper reviews the properties of a range of Ge-on-GaAs film resistance thermometers that cove... more This paper reviews the properties of a range of Ge-on-GaAs film resistance thermometers that cover the temperature range 0.03 K to 500 K. A new dual element resistance thermometer is described, in which two temperature sensitive elements with overlapping thermometrical characteristics are combined to provide a thermometer with good sensitivity over the measurement range from 0.1 K to 400 K. A novel dual function sensor for concurrent measurements of temperature from 1.5 K to 400 K and magnetic field is also described. This consists of a Ge-GaAs resistance thermometer and an InSb-GaAs Hall-effect magnetic field sensor combined in a single package.

Physica C: Superconductivity, 1992

The magnetic shielding properties of YBa2Cu3O7-x coatings, sprayed on silver cylinders with the c... more The magnetic shielding properties of YBa2Cu3O7-x coatings, sprayed on silver cylinders with the continuous detonation spray (CDS) technique, have been investigated in weak magnetic fields. Extended films 40-80 mum thick showed flat-sided sharp-cornered hysteresis loops. Critical penetration field values, when scaled for thickness according to Bean's model were 1.6-3.7 mTmm-1 at 77.3 K and 21-35 mTmm-1 at 4.2 K. In

Results are reported of a study concerning the variation in isotopic composition of a limited num... more Results are reported of a study concerning the variation in isotopic composition of a limited number of neon samples of commercial origin and the resulting influence on the temperature of the triple point of this element. All seven neon samples investigated were found to contain more 22Ne than neon in air, and the amount fraction of 22Ne varied by as much as 0.2% from sample to sample. This variation corresponds to a range of triple-point temperatures (Ttp) of more than 200 microK, much larger than the state-of-the-art uncertainty in the realization of this phase transition for metrological purposes. Deviations in the amount fractions of 21Ne were irrelevant, as far as their effect on T(tp) is concerned, though they may have relevance to other isotope studies. Ratios of amounts of neon isotopes at IRMM-Geel were obtained using the same measurement procedures, and instrumentation developed in the framework of the redetermination of the Avogadro constant and all significant sources of uncertainty were taken into account. The repeatability of the ion current ratio measurements on individual samples was 5 x 10(-5) relative. All uncertainty statements are made following the ISO/BIPM Guide to the Expression of Uncertainty in Measurements. Whereas these results proved unexpected, a more comprehensive study will follow incorporating a much wider range of samples of commercial origin.

ACTA IMEKO

The results of the CODATA 2017 adjustment and the consequent stipulation of the numerical values ... more The results of the CODATA 2017 adjustment and the consequent stipulation of the numerical values of the constants are essential considerations concerning the consequences of the CGPM accepting the CIPM proposal for the revision of the SI. This paper raises (unresolved) questions on these results, specifically concerning the numerical value of the Planck constant

Accreditation and Quality Assurance, Apr 20, 2010

ABSTRACT

In measurement science the object of a measurement is called “measurand”. It is defined in VIM:20... more In measurement science the object of a measurement is called “measurand”. It is defined in VIM:2012 clause 2.3 as “quantity intended to be measured” (but in GUM:1995, B.2.9 it is defined instead according to VIM:1993 clause 2.6 “particular quantity subject to measurement”. In VIM:2012, NOTE 1 to clause 2.3 specifies “the specification of a measurand requires … description [i.e., a model] of the state of the phenomenon, body, or substance”. The concept of measurand should be shared by the relevant Community, because the same measurand is supposed to be the object of replicated measures that must be comparable, i.e., it should be recognised as a quantity having a current recognisable meaning for the community. In the dialect of the science philosophers, this means that it should be projected into a “social framework”. Also in the scientific frame this means that the measurand model must be of the “prescriptive” type, meaning “giving directions or injunctions”— not always meaning “phys...

AIP Conference Proceedings, 2003

An overview of the main results of an international star intercomparison of low-temperature fixed... more An overview of the main results of an international star intercomparison of low-temperature fixed points is given. Between 1997 and 2002, 52 sealed triple-point cells (STPCs) of the thirteen laboratories represented by the authors have been investigated at PTB. The STPCs are used to realise the triple points of hydrogen, neon, oxygen, and argon, respectively, as defining fixed points of

Advances in Cryogenic Engineering, 1984

As in many other countries, attention was focussed in Italy recently on large-scale applications ... more As in many other countries, attention was focussed in Italy recently on large-scale applications of superconductivity. In 1978 a National Project on Applied Superconductivity was financed by the National Research Council (CNR), mainly centered on the design of a large superconducting generator, with some related experimental exercises on cryogenic technology and related problems. In the framework of this Project, the Istituto di Metrologia “G.Colonnetti” (IMGC) of the CNR was given the job to set up a facility for the characterization of the types of transducers involved in the operation of cryogenic machinery. In fact, the specifications of commercially available transducers were quite unsatisfactory (the situation has not improved much since then). of advanced cryogenic projects active around the world and the research and development on instrumentation that certainly had to be done by single industries or laboratories. Perhaps, this was due to the fact that results have a limited interest for other users, if accuracy in the characterization is limited or if information about the reliability (especially long-term) of the selected or newly studied devices is lacking.

Metrologia, 2014

ABSTRACT This note discusses some problems that should be taken into account in the implementatio... more ABSTRACT This note discusses some problems that should be taken into account in the implementation of the proposed use of fundamental constants in the definition of measurement units: use of CODATA adjusted values of the constants for this specific purpose; how the CODATA Task Group could continue performing meaningful least squares adjustments of the fundamental constants taking into account future data. Online Free at http://stacks.iop.org/0026-1394/51/L1

Measurement

Abstract The paper is an adjourned digest of critical features to be considered should the propos... more Abstract The paper is an adjourned digest of critical features to be considered should the proposed use of constants in the definition of measurement units of the SI be implemented: lack of a definitional realisation method; continuity requirement; individual base-unit definitions; possibility of future new determination of the numerical values of the constants; New SI hierarchy ladder. In addition, a critical review is presented of the text of the CCU 2016 Draft, Sections 1 and 2, of the 9th SI Brochure. Summary tables and a Glossary are included.

Advances in Cryogenic Engineering, 1978

The defining points of the International Practical Temperature Scale issued in 1968 (IPTS-68) [1]... more The defining points of the International Practical Temperature Scale issued in 1968 (IPTS-68) [1] involve five boiling points and three triple points from 13.81 to 273.15 K. Shortly after its adoption, the many fixed points involved in the new definition were found to be quite difficult to realize even for national laboratories; KOL, NPL, NRC, and PRMI* have only recently realized all the fixed points. In the course of the studies in these and other laboratories, the information on fixed points has greatly increased since 1968. Boiling-point temperatures appeared to be affected by impurities in the gas sample; thus, the dew point was sometimes preferred [2]. In addition, the measurement of pressure was necessary, and for some gases this had to be performed with a high degree of accuracy. At the same time, careful studies first made by Ancsin [3] showed that with a calorimetric method it was possible to obtain excellent results with triple points (t.p.); as a consequence, the triple point of argon (83.798 K) was introduced in the amended 1975 version of the IPTS-68 as an alternative to the normal boiling point (n.b.p.) of oxygen (90.188 K).

Advances in Cryogenic Engineering, 1998

Mechanical creep of the diaphragm is well recognized as a major problem for obtaining a reproduci... more Mechanical creep of the diaphragm is well recognized as a major problem for obtaining a reproducible cryogenic pressure transducer and it is mainly caused by the stress at the diaphragm edge, where this is rigidly constrained to the transducer body. The double-diaphragm design alleviates this problem. In this design, the rigid constraint of the diaphragm edge is replaced by a (non-ideal) hinge between two identical diaphragms, which allows for a considerable improvement of the reproducibility on thermal cycling. Sapphire has normally been used for this design because of its excellent elastic properties. However, the quality of the results critically depends on technological details of the fabrication.

Recent results in the development of resistance thermometers based on germanium films on gallium ... more Recent results in the development of resistance thermometers based on germanium films on gallium arsenide are summarized. Preliminary results in the development of a new generation of radiation-resistant thermometers and multifunction sensors intended for use in the range 0.03 to 500 K in the presence of high magnetic fields are discussed. These sensors have been produced in an international collaboration recently funded through the EU INTAS program.

This paper reviews the properties of a range of Ge-on-GaAs film resistance thermometers that cove... more This paper reviews the properties of a range of Ge-on-GaAs film resistance thermometers that cover the temperature range 0.03 K to 500 K. A new dual element resistance thermometer is described, in which two temperature sensitive elements with overlapping thermometrical characteristics are combined to provide a thermometer with good sensitivity over the measurement range from 0.1 K to 400 K. A novel dual function sensor for concurrent measurements of temperature from 1.5 K to 400 K and magnetic field is also described. This consists of a Ge-GaAs resistance thermometer and an InSb-GaAs Hall-effect magnetic field sensor combined in a single package.

Physica C: Superconductivity, 1992

The magnetic shielding properties of YBa2Cu3O7-x coatings, sprayed on silver cylinders with the c... more The magnetic shielding properties of YBa2Cu3O7-x coatings, sprayed on silver cylinders with the continuous detonation spray (CDS) technique, have been investigated in weak magnetic fields. Extended films 40-80 mum thick showed flat-sided sharp-cornered hysteresis loops. Critical penetration field values, when scaled for thickness according to Bean's model were 1.6-3.7 mTmm-1 at 77.3 K and 21-35 mTmm-1 at 4.2 K. In

Results are reported of a study concerning the variation in isotopic composition of a limited num... more Results are reported of a study concerning the variation in isotopic composition of a limited number of neon samples of commercial origin and the resulting influence on the temperature of the triple point of this element. All seven neon samples investigated were found to contain more 22Ne than neon in air, and the amount fraction of 22Ne varied by as much as 0.2% from sample to sample. This variation corresponds to a range of triple-point temperatures (Ttp) of more than 200 microK, much larger than the state-of-the-art uncertainty in the realization of this phase transition for metrological purposes. Deviations in the amount fractions of 21Ne were irrelevant, as far as their effect on T(tp) is concerned, though they may have relevance to other isotope studies. Ratios of amounts of neon isotopes at IRMM-Geel were obtained using the same measurement procedures, and instrumentation developed in the framework of the redetermination of the Avogadro constant and all significant sources of uncertainty were taken into account. The repeatability of the ion current ratio measurements on individual samples was 5 x 10(-5) relative. All uncertainty statements are made following the ISO/BIPM Guide to the Expression of Uncertainty in Measurements. Whereas these results proved unexpected, a more comprehensive study will follow incorporating a much wider range of samples of commercial origin.

ACTA IMEKO

The results of the CODATA 2017 adjustment and the consequent stipulation of the numerical values ... more The results of the CODATA 2017 adjustment and the consequent stipulation of the numerical values of the constants are essential considerations concerning the consequences of the CGPM accepting the CIPM proposal for the revision of the SI. This paper raises (unresolved) questions on these results, specifically concerning the numerical value of the Planck constant

Accreditation and Quality Assurance, Apr 20, 2010

ABSTRACT