Books
F. Pavese et al. (editors)
Advanced Mathematical and Computational Tools in Metrology VII
International and National Journals
M. Astrua, M. Battuello, F. Girard
Facility for the calibration of Pt/Pd thermocouples in the temperature range from 960 ºC to 1500 ºC
Measurement Science and Technology, no. 17, pp. 2186-2190, 2006.
Five Pt/Pd thermocouples, constructed and calibrated at IMGC at fixed points in the temperature range from 0 ºC to the Ag point, were calibrated by comparison with the local primary standard radiation thermometer with the aim of replacing the presently used Pt/Pt-Rh alloy thermocouples as secondary reference standards up to 1500 ºC. To fully exploit accuracy of Pt/Pd thermocouples, high-level calibration techniques need to be adopted. For this purpose, a new high-temperature three-zone furnace was arranged and characterized in order to obtain the best axial uniformity and a specially designed blackbody cavity was used as a transfer source for calibrating the thermocouples in the temperature range from 962 ºC up to 1500 ºC. At the end of the comparison measurements, additional calibrations at the Ag fixed point were made, in order to check the stability of the thermocouples'signals. A comparison between experimental results and the reference function is presented and an extrapolation of the fixed-point calibration data is analysed.
M. Stock, S. Solve, D. del Campo, V. Chimenti, E. Méndez-Lango, H. Liedber, P. P. M. Steur, P. Marcarino, R. Dematteis, E. Filipe, I. Lobo, K. H. Kang, K.S. Gam, Y.-G. Kim, E. Renaot, G. Bonnier, M. Valin, R. White, T. D. Dransfield, Y. Duan, Y. Xiaoke, G. Strouse, M. Ballico, D. Sukkar, M. Arai, A. Mans, M. de Groot, O. Kerkhof, R. Rusby, J. Gray, D. Head, K. Hill, E. Tegeler, U. Noatsch, S. Duris, H. Y. Kho, S. Ugur, A. Pokhodun, S.F. Gerasimov
Final Report on CCT-K7: Key comparison of water triple point cells
Metrologia, Vol. 43, 03001 (Technical Supplement 2006).
The triple point of water serves to define the kelvin, the unit of thermodynamic temperature, in the International System of Units (SI). Furthermore, it is the most important fixed point of the International Temperature Scale of 1990 (ITS-90). Any uncertainty in the realization of the triple point of water contributes directly to the measurement uncertainty over the wide temperature range from 13.8033 K to 1234.93 K. The Consultative Committee for Thermometry (CCT) decided at its 21st meeting in 2001 to carry out a comparison of water triple point cells and charged the BIPM with its organization. Water triple point cells from 20 national metrology institutes were carried to the BIPM and were compared with highest accuracy with two reference cells. The small day-to-day changes of the reference cells were determined by a least-squares technique. Prior to the measurements at the BIPM, the transfer cells were compared with the corresponding national references and therefore also allow comparison of the national references of the water triple point. This report presents the results of this comparison and gives detailed information about the measurements made at the BIPM and in the participating laboratories. It was found that the transfer cells show a standard deviation of 50 µK; the difference between the extremes is 160 µK. The same spread is observed between the national references. The most important result of this work is that a correlation between the isotopic composition of the cell water and the triple point temperature was observed. To reduce the spread between different realizations, it is therefore proposed that the definition of the kelvin should refer to water of a specified isotopic composition. The CCT recommended to the International Committee of Weights and Measures (CIPM) to clarify the definition of the kelvin in the SI brochure by explicitly referring to water with the isotopic composition of Vienna Standard Mean Ocean Water (VSMOW). The CIPM accepted this recommendation and the next edition of the SI brochure will include this specification.
F. Pavese, E. Filipe
Some metrological considerations about replicated measurements on standards
Metrologia, Vol. 43, no. 5, pp. 419-425, 2006.
This paper discusses the issue of repeated versus non-repeated measurements on standards. Starting from the general issue of replication of measurement operations, we consider the consequences of the differences that these two types of measurements entail in the comparison of standards. We look at MRA key comparisons (KCs) as a specific case. Recent developments seem to have somewhat obscured the fact that the replication and combination of observations is the everyday task of NMIs. Therefore, this paper first recalls the many facets of intra-laboratory measurements on standards, some not very different from the inter-laboratory exercises. The meaning of the replicated observations is analysed starting from this context. Then the issue is examined in the context of inter-laboratory comparisons, namely, in the case of KCs. Some of the consequences for the statistical treatment of repeated and non-repeated measurement data are illustrated and solutions proposed.
L. Lipinski, A. Kowal, A. Szmyrka-Grzebyk, H. Manuszkiewicz, P. P. M. Steur, F. Pavese
The triple point of nitrogen
Metrologia, Vol. 43, no 5, pp. 435-440, 2006.
We present accurate measurements of the triple point of nitrogen. The quality of this triple point is once more confirmed, and its temperature value is found to be T90 = 63.1526 K (expanded uncertainty U = 0.30 mK, reproducibility better than 0.1 mK). This is the first direct determination of this point on ITS-90 since the introduction of the scale. This point is useful as a non-uniqueness checkpoint.
G. Grenci, S. Denis, L. Dusoulier, F. Pavese, N. Penazzi
Preparation and characterization of YBa2Cu3O7-x thick films deposited on silver substrates by the electrophoretic deposition technique for magnetic screening applications
Superconductor Science and Technology, Vol. 19, no. 4, pp. 249-255, 2006.
The production of magnetic shields using high-temperature superconductors (HTS) is not straightforward, as these materials are brittle ceramics. In this paper, we report the results of investigations concerning the use of the electrophoretic deposition (EPD) technique to produce magnetic shields of various shapes and with large surface areas, in the form of a thick coating of HTS on a metallic substrate. For the first time, we report shielding characterization of samples prepared by the EPD technique. The most important problems concern the choice of the process parameters and the heat treatment of the coating, in order to obtain a dense and well-connected polycrystalline system. We have used the HTS compound YBa2Cu3O7-x as the coating material and silver as the substrate. An optimized heat treatment, in an atmosphere with poor oxygen content, was chosen following experimental investigations. Different samples were produced in the form of slabs for chemical, structural and electrical characterization. A cylindrical sample was prepared for magnetic shielding measurements at 77 K. With an applied magnetic field parallel to its axis, the cylinder presents a high level of shielding (>80 dB) at low frequencies, for applied inductions lower than 0.1 mT. If the applied induction is higher than 0.25 mT, the magnetic field inside the cylinder strongly increases. This value is close to the field of penetration given by Bean's model, taking a critical current density of 500 A cm-2 measured by the four-probe technique on similar samples.
F. Pavese
A metrologist viewpoint on some statistical issues concerning the comparison of non-repeated measurement data, namely MRA key comparisons
Measurement (Special Issue), pp. 419-425, 2006.
Since the Mutual Recognition Arrangement (MRA) came into effect, many discussions are taking place about the Key Comparison (KC) protocols and the subsequent statistical treatment, concerning the experimental data to be collected and be analysed. The discussion presently going on is often omitting, or giving for granted, some preliminary important steps that, on the contrary, are still contentious. The paper is an attempt to list in a comprehensive way the above problems and to suggest ways to progress toward solutions.
F. Righini
Evaluation of a pulse-heating reflectometric technique
International Journal of Thermophysics, Vol. 27, pp. 1-12, 2006.
The classical millisecond-resolution pulse-heating method makes use of tubular specimens with a rectangular blackbody hole for accurate measurements of several thermophysical properties at high temperatures. An alternative measurement technique that uses simple strip specimens has been developed at the IMGC (Italy). The normal spectral emissivity of the pulse-heated strip is measured by integrating sphere reflectometry, using a modulated laser beam to discriminate between the reflected radiation and that self-emitted by the specimen. After a brief description of the measurement system and a review of the main experimental results, attention is devoted to current developments and possible improvements of the method, with particular attention to experiments performed at the melting point. The measurement technique is analyzed and evaluated, with a brief description of potential future measurement possibilities.
L. Rosso, V. Fernicola
Time-and-frequency-domain analyses of fluorescence lifetime for temperature sensing
Review of Scientific Instruments, Vol. 77, No. 034901, 2006.
Fluorescence lifetime detection is widely used for sensing physical and chemical quantities. The measurement accuracy of fluorescence lifetime-based sensing systems, either in time or frequency domain relies on their capability of detection and analysis of low level signal superimposed to noise. In this work a quantitative assessment of several data processing and analysis methods for the estimation of the fluorescence lifetime was carried out by using an experimental arrangement based on a fiber optic temperature sensor system. A comparison between the various methods was performed using actual signals from an optical sensing medium. The basic principles of time- and frequency-domain lifetime measurements were also reviewed and discussed in order to point out the limit of the cw frequency-domain approach and to suggest a way to overcome it. The investigated lifetime interval was from 200 to about 2200 µs, corresponding to a temperature span of the sensor of about 300 ºC. The results showed that in time domain (such as with Marquardt, integration, and log-fit algorithms) a good agreement, with relative differences from 0.2% to 0.5%, can be reached. Frequency-domain results based on an N-point fast Fourier transform (FFT) compare favorably with the previous ones in the long lifetime region (resulting in relative differences lower than 0.2%) with larger differences for short lifetimes. For each data processing method, the uncertainty associated with lifetime estimation was evaluated. Sampling and harmonics effects on the estimation accuracy for N-point FFTs were also investigated to trade-off between speed and accuracy of the algorithm in view of its application in real-time detection systems.
V. Fernicola
Measuring air humidity
The Chalcolithic Mummy. Vol. 3, Chap. 6, pp. 97-112, Collana del Museo Archeologico dell'Alto Adige, Folio Verlag, Vienna e Bolzano, 2006.
The climate-controlled cell that accommodates the Similaun mummy must accurately reproduce the best conditions for its proper preservation. The verification of the performance of the cell control system requires specific investigation techniques and near-state-of-the-art measurement capabilities for the environmental physical quantities (i.e., temperature and humidity). The issues concerning the basic definitions and principles, the air humidity measuring instruments - with emphasis to measurements below 0 ºC - and the investigation methods for uncertainty estimation are dealt with in this chapter.
P. Ciarlini, D. Ichim
Free-knot cubic spline modelling in cryogenic thermometer calibration
Measurement, Vol. 39, no. 9, pp. 815-820, 2006.
In a calibration process of thousands of thermometers, optimization of the experimental design is an important step to save time and costs. In this paper, a modelling procedure is proposed for the construction of a suitable cubic spline approximation of the R-T characteristic of cryogenic thermometers. An iterative algorithm is used to estimate the parameters of a free-knot cubic spline model. Moreover, the minimum number of measurement points and their locations in the experimental design, as related to the spline parameters, are obtained via an heuristic study.
F. Pavese
Special issue: Advanced mathematical tools for measurement in metrology and testing - Preface
Measurement, Vol. 39, no. 9, pp. 779-781, 2006.
G. Della Gatta, T. Usacheva, E. Badea, B. Palecz, D. Ichim
Thermodynamics of solvation of some small peptides in water at T = 298.15 K
Journal of Chemical Thermodynamics, Vol. 38, no. 8, pp. 1054-1061, 2006.
The enthalpies of solution in water, ΔsolHm, of some small peptides, namely the amides of five N-acetyl substituted amino acids of glycine, l-alanine, l-proline, l-valine, l-leucine and two cyclic anhydrides of glycine and l-sarcosine (diketopiperazines), were measured by isothermal calorimetry at T = (296.84, 306.89, and 316.95) K. The enthalpies of solution at infinite dilution at T = 298.15 K were derived and added to the enthalpies of sublimation, ΔsubHºm, at the same temperature, to obtain the corresponding solvation enthalpies at infinite dilution, ΔsolvH∞m. Moreover, the partial molar heat capacities at infinite dilution at T = 298.15 K, C∞p,2, were calculated by adding molar heat capacities of solid small peptides, Cp,m(cr), to the ΔsolC∞p,m values obtained from our experimental data. CH2 group contributions, in terms of solvation enthalpy and partial molar heat capacity, were -3.2 kJ × mol-1 and 89.3 J × K-1 × mol-1, respectively, in good agreement with the literature data. Simple additive methods were used to estimate the average molar enthalpy of solvation and partial molar heat capacity at infinite dilution for the 1/2CONH CONH functional group in the small peptides. Values obtained were -46.7 kJ × mol-1 for solvation enthalpy and -42.4 J × K-1 × mol-1 for partial molar heat capacity, significantly lower than values obtained for the CONH functional group in monofunctional model compounds.
A. Meda, A. Merlone, P. Steur
Il 40º compleanno del reattore Triga Mark II
Tutto Misure, n. 2, p. 142, 2006.
Conference Proceedings
D. Ichim, F. Pavese
A comparison of the initial uncertainty budget and an estimate of the posterior uncertainties, in the case of large batches of calibration data: the LHC thermometers at CERN
Proceedings of the IMEKO XVIII World Congress, Rio de Janeiro (Brazil), September 2006 (on cd rom).
The paper will describe the techniques that have been used to perform the comparison on large batches of cryogenic semiconductor-type thermometers, calibrated for the CERN LHC and the main results obtained: they concern either the uncertainty of the CernoxTM thermometers under calibration and the behaviour of the standards used during the calibrations.
F. Pavese
Some notes on replicated measurements in metrology and testing: classification into repeated or non-repeated measurements
Proceedings of the IMEKO XVIII World Congress (oral session), Rio de Janeiro (Brazil), September 2006 (on cd rom).
F. Righini
The world of subsecond thermophysics
Proceedings of the IMEKO XVIII World Congress (plenary speaker), Rio de Janeiro (Brazil), September 2006 (on cd rom).
The measurement techniques developed in the last thirty-five years for the accurate measurement of thermophysical properties at high temperatures (800-3700 K) using subsecond current-heating are reviewed. Only experiments of total duration around 1 s are considered, with data acquisition performed at the sub-millisecond level. Emphasis is placed on the physics of the different techniques, as developed in major national measurement institutes around the world. A complete survey is provided, covering multiproperty experiments, extensions to thermal expansion and thermal conductivity and measurements at the melting point. An intercomparison of experimental results available in the literature provides an indirect evaluation of the validity of these techniques.
F. Pavese
The effect of the variability in the isotopic composition of gases on top-accuracy cryogenic temperature standards and remedies
AIP Conference Proceedings, Vol. 823, pp. 451-458, Advances in Cryogenic Engineering: Trans. of the Cryogenic Engineering Conference, April 2006.
In the cryogenic range, temperature standards are based on the measurement of phase transitions of substances that are gaseous at room temperature. For total uncertainty budgets today approaching, for the most accurate realizations, 50 µK, the effect of different isotopic compositions in the samples measured can become so large as to be the leading component of the total uncertainty budget. The variability of the isotopic composition is a well-known issue and is regularly monitored and reviewed by bodies such as the IUPAC. However, these data cover the whole spectrum of the variability observed on the earth. The actual variability that can be observed when buying commercial substances could be smaller to such an extent to alleviate or eliminate the practical problem, or could instead remain relevant. Only recently attention has been paid to the latter problem and the results were partially unexpected. This paper briefly reviews the modern analytical and thermal techniques, the resulting present knowledge and problems, and some recent solutions.
V. F. Mitin, N. S. Boltovets, V. V. Basanets, V. V. Kholevchuk, I. Yu. Nemish, E. V. Mitin, P. C. McDonald, F. Pavese
New thermometers and multisensors for cryogenic temperature and magnetic field measurements
AIP Conference Proceedings, Vol. 823, pp. 1243-1250, Advances in Cryogenic Engineering: Transactions of the Cryogenic Engineering Conference, April 2006.
This paper presents the characteristics of a new generation of temperature multifunction sensors based on germanium-film resistance thermometers deposited on a semi-insulating GaAs substrate: as dual-range thermometers (dual-element resistance thermometer -DERT) or for concurrent measurements of temperature and magnetic field, using a InSb-film Hall generator (dual function sensors -DFS). They have been developed using micro-electronic design and production methods, in an international collaboration (INTAS) supported by the European Union. A range of resistance thermometers is described, providing, for scientific and industrial use, high sensitivity over complementary temperature ranges, within the overall range from 0.03 to 500 K, in a number of different packages. The multisensors are intended for use in the 0.3 K to 400 K temperature range, for magnetic field up to 30 T and to be resistant to ionizing radiations.
A. Merlone
Experiment for the determination of the gas constant R at INRiM
Workshop on "Progress in Determining the Boltzmann Constant", Berlin (Germany), PTB, 19 Ottobre 2006.
S. Giunta, A. Merlone, P.P.M. Steur, R. Dematteis
Dedicated electronics for fixed points furnaces control
Workshop "Toward more accurate temperature fixed points", EUROMET Project 732, LNE-INM/CNAM Saint Denis (France), November 2006.
A. Merlone, S. Giunta, A. Tiziani, R. Dematteis, P.P.M. Steur
New Heat Pipes for temperature fixed points
Workshop "Toward more accurate temperature fixed points", EUROMET Project 732, LNE-INM/CNAM Saint Denis (France), November 2006.
Technical Reports
M. Astrua, L. Iacomini, A. Mangano, A. Tiziani
Verifica delle prestazioni di un tubo di calore al Potassio. Performance Test of a Potassium Heat Pipe
Rapporto Tecnico INRIM n. 3, febbraio 2006.
Il tubo di calore al Potassio, presente nel Laboratorio Tarature di Termometria per contatto, è dedicato alla taratura di termocoppie tra 550 ºC e 950 ºC ed è equipaggiato con due sistemi di raffreddamento ad acqua: un circuito per il raffreddamento del mantello esterno ed un circuito attorno ai pozzetti di misura per la condensazione del fluido di lavoro. A causa di una perdita nel secondo circuito, il materiale isolante che avvolge il tubo di calore si è impregnato di acqua, generando alterazioni delle prestazioni del tubo di calore e mettendo in serio pericolo il funzionamento dell'apparato. È stato quindi necessario effettuare un'operazione di ripristino dell'apparato, mediante la sostituzione dell'isolante e della serpentina del circuito con del nuovo materiale isolante e con un sistema di raffreddamento più robusto. Il presente rapporto illustra i dati acquisiti durante la campagna di caratterizzazione del sistema, volta a verificare le eventuali variazioni nelle prestazioni dell'apparato causate dalle operazioni di manutenzione.
V. C. Fernicola
Calcolo di alcuni parametri termodinamici dell'aria umida
Rapporto Tecnico INRIM n. 17, luglio 2006.
Il rapporto tecnico riassume le principali relazioni termodinamiche ed i metodi di calcolo di alcuni parametri termodinamici dell'aria umida utilizzati in igrometria e psicrometria. In particolare, viene considerato il caso di misure termo-igrometriche combinate con sensore di umidità relativa e sensore di temperatura separati da cui derivare, a partire dall'umidità relativa e dalla temperatura dell'aria, gli altri parametri d'interesse.