Search

Your search keyword '"Bonnier G"' showing total 156 results
Start Over Author "Bonnier G"
156 results on '"Bonnier G"'

12. Intercomparison of the Realizations of the ITS-90 from 83.8058 K to 692.677 K among European NMIs

Author

Renaot, E., Hermier, Y., Valin, M. H., Bonnier, G., Adunka, F., Van Der Linden, A., Dobre, M., Šmíd, M., Bronnum, A., Weckstrom, T., Tegeler, E., Noatsch, U., Anagnostou, M., Turzo-Andras, E., Nemeth, S., White, M., Marcarino, P., Steur, P., Pauzha, A., Augevicius, V., de Groot, M., Nielsen, J., Helgesen, F., Roszkowski, W., Grudniewicz, E., Kuna, R., Filipe, E., Lobo, I., Gaita, S., Chimenti, V., Ivarsson, J., Duris, S., Ranostaj, J., Bojkovski, J., Steiner, A., Ugur, S., Gray, J., Bruce, S., Rusby, R., and Head, D.

Published
2008
Full Text
View/download PDF

14. Personalized pathology maps to quantify diffuse and focal brain damage

Author

Bonnier, G., Fischi-Gomez, E., Roche, A., Hilbert, T., Kober, T., Krueger, G., and Granziera, C.

Subjects
Adult, Male, Brain Mapping, Multiple Sclerosis, Personalized MRI, Brain, Quantitative MRI, lcsh:Computer applications to medicine. Medical informatics, Magnetic Resonance Imaging, lcsh:RC346-429, Article, Cohort Studies, Deviation maps, Cross-Sectional Studies, MRI pathology, Brain Injuries, Image Interpretation, Computer-Assisted, Multi-parametric MRI, lcsh:R858-859.7, Humans, Brain/pathology, Brain Injuries/pathology, Female, Image Interpretation, Computer-Assisted/methods, Magnetic Resonance Imaging/methods, Multiple Sclerosis/pathology, Multiple sclerosis, lcsh:Neurology. Diseases of the nervous system
Abstract

Background and objectives: Quantitative MRI (qMRI) permits the quantification of brain changes compatible with inflammation, degeneration and repair in multiple sclerosis (MS) patients. In this study, we propose a new method to provide personalized maps of tissue alterations and longitudinal brain changes based on different qMRI metrics, which provide complementary information about brain pathology. Methods: We performed baseline and two-years follow-up on (i) 13 relapsing-remitting MS patients and (ii) four healthy controls. A group consisting of up to 65 healthy controls was used to compute the reference distribution of qMRI metrics in healthy tissue. All subjects underwent 3T MRI examinations including T1, T2, T2* relaxation and Magnetization Transfer Ratio (MTR) imaging. We used a recent partial volume estimation algorithm to estimate the concentration of different brain tissue types on T1 maps; then, we computed a deviation map (z-score map) for each contrast at both time-points. Finally, we subtracted those deviation maps only for voxels showing a significant difference with healthy tissue in one of the time points, to obtain a difference map for each subject. Results and conclusion: Control subjects did not show any significant z-score deviations or longitudinal z-score changes. On the other hand, MS patients showed brain regions with cross-sectional and longitudinal concomitant increase in T1, T2, T2* z-scores and decrease of MTR z-scores, suggesting brain tissue degeneration/loss. In the lesion periphery, we observed areas with cross-sectional and longitudinal decreased T1/T2 and slight decrease in T2* most likely related to iron accumulation. Moreover, we measured longitudinal decrease in T1, T2 - and to a lesser extent in T2* - as well as a concomitant increase in MTR, suggesting remyelination/repair.In summary, we have developed a method that provides whole-brain personalized maps of cross-sectional and longitudinal changes in MS patients, which are computed in patient space. These maps may open new perspectives to complement and support radiological evaluation of brain damage for a given patient. Keywords: Multi-parametric MRI, Quantitative MRI, Personalized MRI, Multiple sclerosis, Deviation maps, MRI pathology

Published
2018

15. Calibration of benthic foraminifera elemental ratios from the Northeastern Atlantic

Author

Sepulcre, S., Tribondeau, M., Bassinot, Franck, Mojtahid, Meryem, Nardelli, Maria Pia, Dessandier, P-A, Bonnier, G., Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique - Angers (LPG-ANGERS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU]Sciences of the Universe [physics]
Published
2017

18. Proof-of-Concept Study for Reflectance Pulse Oximetry Using Optical-Fibre-Based Sensors

Author

Annaheim Simon, Braun Fabian, Bernhard Leah, Pfammatter Amarin, Proença Martin, Bonnier Guillaume, Ferrario Damien, Lemay Mathieu, and Rossi René M.

Subjects
polymeric optical fibres, textile-based sensor, ppg, spo2, reflectance pulse oximetry, blood pressure, Medicine
Abstract

Optical fibres enable to design of new textile-based sensors for an unobtrusive, continuous, and long-term acquisition of photoplethysmography (PPG) signals. However, no research has been done about the accuracy of measuring blood oxygen saturation (SpO2) and the feasibility of PPG-based blood pressure measurement. This proof-ofconcept study examined these aspects for a woven sensing patch applied on the forehead in five healthy participants. During a controlled desaturation study, SpO2 estimation revealed an amplitude of the root-mean-squared error (ARMS) of 3.6%, and acceptable signal quality for blood pressure estimation was achieved for 40% of all data. These results indicate that textile-based sensors can reach the required PPG signal quality to simultaneously estimate multiple vital signs, including blood pressure.

Published
2022
Full Text
View/download PDF

19. The Combined Quantification and Interpretation of Multiple Quantitative Magnetic Resonance Imaging Metrics Enlightens Longitudinal Changes Compatible with Brain Repair in Relapsing-Remitting Multiple Sclerosis Patients

Author

Bonnier, G., Marechal, B., Fartaria, M.J., Marques, J.P., Simioni, S., Schluep, M., Du Pasquier, R., Thiran, J.-P., Krueger, G., Granziera, C., Bonnier, G., Marechal, B., Fartaria, M.J., Marques, J.P., Simioni, S., Schluep, M., Du Pasquier, R., Thiran, J.-P., Krueger, G., and Granziera, C.

Abstract

Contains fulltext : 181742.pdf (publisher's version ) (Open Access), Objective: Quantitative and semi-quantitative MRI (qMRI) metrics provide complementary specificity and differential sensitivity to pathological brain changes compatible with brain inflammation, degeneration and repair. Moreover, advanced MRI metrics with overlapping elements amplify the true tissue-related information and limit measurement noise. In this work, we combined multiple advanced MRI parameters to assess focal and diffuse brain changes over 2 years in a group of early-stage relapsing-remitting MS patients. Methods: Thirty relapsing-remitting MS patients with less than 5-year disease duration and nine healthy subjects underwent 3T MRI at baseline and after 2 years including T1, T2, T2* relaxometry, and magnetization transfer imaging. To assess longitudinal changes in normal-appearing tissue and lesions, we used analyses of variance and Bonferroni correction for multiple comparisons. Multivariate linear regression was used to assess the correlation between clinical outcome and multiparametric MRI changes in lesions and normal appearing tissue. Results: In patients, we measured a significant longitudinal decrease of mean T2 relaxation times in normal appearing white matter (p = 0.005) and a decrease of T1 relaxation times in the pallidum (p < 0.05), which are compatible with edema reabsorption and/or iron deposition. No longitudinal changes in qMRI metrics were observed in controls. In MS lesions, we measured a decrease in T1 relaxation time (p-value < 2.2e-16) and a significant increase in MTR (p-value < 1e-6), suggesting repair mechanisms such as remyelination, increased axonal density and/or a gliosis. Last, the evolution of advanced MRI metrics - and not changes in lesions or brain volume - were correlated to motor and cognitive tests scores evolution (Adj-R2 > 0.4, p < 0.05). In summary, the combination of multiple advanced MRI provided evidence of changes compatible with focal and diffuse brain repair at early MS stages as suggested by histopathological

Published
2017

22. Multiple Sclerosis lesion fingerprint using multicontrast MRI

Author

Bonnier, G., Roche, A., Romascano, D., Simioni, S., Meskaldji, D., Rotzinger, D., Lin, Ying Chia, Gloria Menegaz, Schluep, M., Du Pasquier, R., Johannes, T., Sumpf, Frahm, J., Thiran, J. P. H., Krueger, G., and Granziera, C.

Subjects
Diffusion MRI
Published
2014

23. Cerebellar connectomics provide new biomarkers in early multiple sclerosis

Author

Romascano, D., Meskaldji, D., Bonnier, G., Simioni, S., Rotzinger, D., Lin, Ying Chia, Gloria Menegaz, Roche, A., Schluep, M., Du Pasquier, R., Richiardi, J., Ville, D., Alessandro Daducci, Sumpf T, J., Frahm, J., Thiran, J. P. H., Krueger, G., and Granziera, C.

Subjects
Diffusion MRI
Abstract

The cerebellum is involved in multiple sclerosis (MS), but its implication in early phases is still poorly understood. We investigated structural and functional cerebellar connectivity alterations in early and minimally impaired MS patients, and their correlation to patients’ clinical status. We reconstructed the connectomes of 28 MS patients and 16 healthy controls and performed network statistical analysis. Structural connectivity was found to be altered independently from cerebellar lesion count, volume and disease duration; the microstructural properties of altered connections correlated with patients’ motor and cognitive performance. No topological reorganization or compensatory mechanisms were observed at this stage.

Published
2014

27. Final Report on EUROMET.T-K3:Regional key comparison of the realisations of the ITS-90 from 83.8058 K to 692.677 K

Author

Renaot, E., Hermier, Y., Valin, M.H., Bonnier, G., Adunka, F., van der Linden, A., Dobre, M., Smíd, M., Bronnum, A., Weckström, Thua, Tegeler, E., Noatsch, U., Anagnostou, Miltiadis, Turzó-András, E., Nemeth, S., White, M., Marcarino, P., Steur, P., Pauzha, A., Augevicius, V., de Groot, M.J., Nielsen, J., Helgesen, F., Roszkowski, W., Grudniewicz, E., Kuna, R., Filipe, E., Lobo, I., Gaita, S., Chimenti, V., Ivarsson, J., Duris, S., Ranostaj, J., Bojkovski, J., Steiner, Anton, Ugur, S., Gray, J., Bruce, S., Rusby, R., and Head, D.

Subjects
International Temperature Scale of 1990, Homogeneous, Statistics, General Engineering, Fixed point, Mutual recognition, Equivalence (measure theory), Freezing point, Mathematics
Abstract

This report presents the results of the EUROMET regional key comparison corresponding to CCT-K3 and covering the temperature range from 83.8058 K (triple point of Ar) to 692.77 K (freezing point of Zn). The comparison involved the six NMIs previously involved in CCT-K3 (BNM-INM/CNAM, SMU, IMGC, NMi-VSL, NPL, PTB) and 18 European national laboratories. The comparison was divided into five different loops coordinated by a co-pilot chosen among the laboratories having participated in the CCT-K3 comparison. BNM-INM/CNAM played the role of pilot in establishing the link between the five loops. In each loop, an artefact in the form of a standard platinum resistance thermometer (SPRT) was circulated among the participant laboratories. In order to have sufficient information about the possible drift of the SPRTs, the co-pilots have performed a calibration over the full temperature range at the beginning and at the end of the loop. Each participant laboratory carried out the measurements in agreement with the protocol. After initial measurements of R(tpw) and successful annealing treatment, each calibration consisted of three measurements of R(t) at each fixed point, in separate realizations. Each measurement was followed by a measurement of R(tpw). The order of fixed points was Zn, Sn, In, Ga, Hg, Ar, but if a fixed point was not available, it was omitted. Values of W(t), and their average value, were calculated. The results were reported to the co-pilot and BNM-INM/CNAM, with uncertainty budgets and other specified data. The results of the comparison were analysed by BNM-INM/CNAM. For the sake of clarity, the results are firstly presented loop by loop. In a second step a EUROMET Reference Value (ERV) taking into account the whole comparison was defined. In order to calculate this ERV advantage was taken of the presence of BNM-INM/CNAM in the five loops; the differences between each laboratory's results and BNM-INM's were considered. The participant laboratories decided during a Workshop organized by the pilot in Vienna in April 2005 to use as ERV the weighted mean rather than the simple mean. The differences (TLab - TERV) are presented with the associated uncertainties. Given that the protocol of the comparison contains a detailed description of how the uncertainties are to be calculated, the uncertainty budgets established by the participants seem consistent or, at least, homogeneous. The degrees of equivalence between the participating laboratories (in the same loop or in different loops) are given with their associated uncertainty. Finally, a method for establishing the bilateral equivalence between the participants in CCT-K3 and in EUROMET'T-K3 is proposed. It is recommend to use a group of 'linking laboratories' composed by the pilot and the co-pilots in order to link EUROMET.T-K3 to CCT-K3. The hypothesis is that the mean temperature of the pilot and co-pilot laboratories is the same in EUROMET.T-K3 as it was in CCT-K3. A specific analysis of the pilot's and co-pilot's results shows that even when the results given by one or several members of the 'linking laboratories' are not positioned in the same place as in EUROMET.T-K3 and CCT-K3 the mean calculated for the group is really reproducible. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Published
2007
Full Text
View/download PDF

29. Comment intégrer les thématiques de l'environnement et les préceptes du développement durable dans une formation au service de la société ?

Author

Abel Coindoz, C., Blanchet, C., Bonnier, G., Bregeon, J., Debrosse, J.P., Deconinck, J.F., Filippi, M., De Gabrielli, A., Garrigues, P., Germon, Jean-Claude, Gondran, Natacha, Grimm, D., Mariotti, A., Mathey, F., Méclot, B., Mombrun, M., Ribeyre, Francis, Rogé, B., Roux-Marchand, W., Vergnes, J., Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico -& Toxico Chimie des systèmes naturels (LPTC), Université Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique (CNRS), Microbiologie du Sol et de l'Environnement (MSE), Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB), Centre Sciences, Information et Technologies pour l'Environnement (SITE-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Institut Mines-Télécom [Paris] (IMT), Département Information, Décision et Evaluation Environnementale (IDEE-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SITE, Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Environnement, Géo-ingénierie et Développement (EGID), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physico -& Toxico Chimie des systèmes naturels ( LPTC ), Université Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique ( CNRS ), Microbiologie du Sol et de l'Environnement ( MSE ), Institut National de la Recherche Agronomique ( INRA ) -Université de Bourgogne ( UB ), Centre Sciences, Information et Technologies pour l'Environnement ( SITE-ENSMSE ), École des Mines de Saint-Étienne ( Mines Saint-Étienne MSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris], Institut Mines-Télécom [Paris], Département Information, Décision et Evaluation Environnementale ( IDEE-ENSMSE ), Institut Mines-Télécom [Paris]-Institut Mines-Télécom [Paris]-SITE, Biogéochimie et écologie des milieux continentaux ( Bioemco ), École normale supérieure - Paris ( ENS Paris ) -Institut National de la Recherche Agronomique ( INRA ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -AgroParisTech-Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Centre National de la Recherche Scientifique ( CNRS ), Environnement, Géo-ingénierie et Développement ( EGID ), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), and Breuil, Florent

Subjects
[SDE.ES] Environmental Sciences/Environmental and Society, [SDE.ES]Environmental Sciences/Environmental and Society, [ SDE.ES ] Environmental Sciences/Environmental and Society
Abstract

http://www.millenaire3.com/uploads/tx_ressm3/Actes_colloque_EEDD2004.pdfhttp://www.millenaire3.com/uploads/tx_ressm3/Actes_colloque_EEDD2004.pdf; International audience; 1. La formation des acteurs - Formation tout au long de la vie versus développement durable - Prise en compte de l' EDD dans la formation professionnelle : la formation comme vecteur du développement durable - Rôle des structures d'enseignement et de formation 2. Comment généraliser la prise en compte de la thématique environnement et de l'EEDD dans l'enseignement supérieur et la recherche!? 3. Quelques réflexions et propositions

Published
2004

30. A European ultralow temperature scale

Author

Mohandas, P, Head, D.I, Rusby, R.L, Schuster, G, Hoffmann, A, Hechtfischer, D, Fellmuth, B, Strehlow, P, Pitre, L, Hermier, Y, Bonnier, G, de Groot, M.J, Storm, A, Jochemsen, R, Nieuwenhuys, G.J, Bosch, W, and Forbes, A

Published
2000
Full Text
View/download PDF

40. Final Report on CCT-K7: Key comparison of water triple point cells

Author

Stock, M, primary, Solve, S, additional, Campo, D del, additional, Chimenti, V, additional, Méndez-Lango, E, additional, Liedberg, H, additional, Steur, P P M, additional, Marcarino, P, additional, Dematteis, R, additional, Filipe, E, additional, Lobo, I, additional, Kang, K H, additional, Gam, K S, additional, Kim, Y-G, additional, Renaot, E, additional, Bonnier, G, additional, Valin, M, additional, White, R, additional, Dransfield, T D, additional, Duan, Y, additional, Xiaoke, Y, additional, Strouse, G, additional, Ballico, M, additional, Sukkar, D, additional, Arai, M, additional, Mans, A, additional, Groot, M de, additional, Kerkhof, O, additional, Rusby, R, additional, Gray, J, additional, Head, D, additional, Hill, K, additional, Tegeler, E, additional, Noatsch, U, additional, Duris, S, additional, Kho, H Y, additional, Ugur, S, additional, Pokhodun, A, additional, and Gerasimov, S F, additional

Published
2006
Full Text
View/download PDF

41. Summary of comparison of realizations of the ITS-90 over the range 83.8058 K to 933.473 K: CCT key comparison CCT-K3

Author

Mangum, B W, primary, Strouse, G F, additional, Guthrie, W F, additional, Pello, R, additional, Stock, M, additional, Renaot, E, additional, Hermier, Y, additional, Bonnier, G, additional, Marcarino, P, additional, Gam, K S, additional, Kang, K H, additional, Kim, Y-G, additional, Nicholas, J V, additional, White, D R, additional, Dransfield, T D, additional, Duan, Y, additional, Qu, Y, additional, Connolly, J, additional, Rusby, R L, additional, Gray, J, additional, Sutton, G J, additional, Head, D I, additional, Hill, K D, additional, Steele, A, additional, Nara, K, additional, Tegeler, E, additional, Noatsch, U, additional, Heyer, D, additional, Fellmuth, B, additional, Thiele-Krivoj, B, additional, Duris, S, additional, Pokhodun, A I, additional, Moiseeva, N P, additional, Ivanova, A G, additional, Groot, M J de, additional, and Dubbeldam, J F, additional

Published
2002
Full Text
View/download PDF

42. A New Generation of Multicells for Cryogenic Fixed Points at BNM/INM.

Author

Hermier, Y., Pitre, L., Geneville, C., Vergé, A., Bonnier, G., Head, D. I., Fellmuth, B., Wolber, L., Szmyrka-Grzebyk, A., Lipinski, L., de Groot, M. J., and Peruzzi, A.

Subjects
THERMOMETER calibration, TEMPERATURE measurements, MERCURY (Element), LOW temperatures
Abstract

In January 2000 a European Project called “MULTICELLS” started, in the field of the realisation of low-temperature standards [1]. In the range from 14 K to 234 K, two competing designs of modular multi-compartment cells (multicells) for the realisation of low-temperature fixed points of the ITS-90 were developed and fabricated by two different partners: BNM-INM and IMGC [2]. The multicells device allows the calibration, in the same run, of up to three thermometers at all the ITS-90 triple points in the low-temperature range, including the mercury point. Several secondary reference points could be optionally added to the system. The limitation of the number of elements is mainly due to thermal effects (thermal homogeneity and response time) and to the dimension of the experimental space of the calorimeter used for measuring the melting curves. In order to reduce the response time, the phase-transition interface of each element of the multicell containing the substance must be in close thermal contact with the thermometers to be calibrated, although the different elements must be easily separated. BNM-INM developed and improved the device in co-operation with the testing partners from other institutes represented by the authors. The technical choices leading to the BNM-INM design are presented and justified. Experimental results on the thermal behaviour of the multicells are given. The tests were performed in accordance with a detailed protocol in order to enable a direct comparison of different designs of the multicells. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

43. Argon Triple-Point Device to Calibrate Long-Stem Thermometers in Quasi-Adiabatic Conditions.

Author

Ahmed, M. G., Hermier, Y., Moussa, M. R., and Bonnier, G.

Subjects
RESISTANCE thermometers, THERMOMETER calibration, PLATINUM, TEMPERATURE measurements
Abstract

An argon triple-point apparatus has been fabricated to calibrate long-stem SPRTs (Standard Platinum Resistance Thermometers) in quasi-adiabatic conditions. The detailed description of this apparatus is given below. The results obtained and a comparison with a system realizing the argon triple point using a continuous heat flux method are presented. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

44. Estimation of Uncertainties in Comparison Calibration of Thermocouples.

Author

Zvizdic, D., Serfezi, D., Bermanec, L. Grgec, Bonnier, G., and Renaot, E.

Subjects
THERMOCOUPLES, THERMOMETER calibration, RESISTANCE thermometers, TEMPERATURE measurements
Abstract

The objective of this paper is to present the methodology for estimation of measurement uncertainties in comparison calibration of thermocouples used in Croatia at the Laboratory for Process Measurements (LPM) and in France at the Bureau National de Métrologie (BNM). The methodology is applied for comparison calibration of rare-metal and industrial base-metal thermocouples within a temperature range from -20 °C to 660 °C with standard platinum resistance thermometers, and from 600 °C to 1050 °C with standard thermocouples. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

45. The “Temperature Amplifier”: an Innovative Application of Pressure-Controlled Heat-Pipes for Calibration of PRTs and Thermocouples.

Author

Renaot, E., Elgourdou, M., and Bonnier, G.

Subjects
THERMOCOUPLES, HEAT pipes, TEMPERATURE measurements, PLATINUM
Abstract

At high temperature (from 600 °C to 962 °C) calibration by comparison of platinum resistance thermometers (PRTs) is limited by the instability and the reliability of the standard high-temperature PRT and by the temperature uniformity in the working volume of furnaces equipped with comparison blocks. To improve its calibration-comparison capability, BNM-INM is studying the possibility of connecting several pressure-controlled heat-pipes, filled with different working fluids, simultaneously to the same pressure control system. The experimental apparatus, called a “temperature amplifier,” is composed of three heat-pipes filled with sodium (Na), potassium (K), and dodecane (Do). © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

46. Thermal Characteristics of a Dodecane Heat-pipe over the Range from 190 to 260 °C and Related Impurity Effects.

Author

Renaot, E., Favreau, J. O., Elgourdou, M., and Bonnier, G.

Subjects
HEAT pipes, TEMPERATURE measurements, VAPOR pressure, THERMODYNAMICS
Abstract

To improve the calibration-comparison capability in the range 600 to 962 °C, the BNM-INM is studying the possibility of connecting to the same pressure control system several heat-pipes filled with different working fluids, in order to set-up a “temperature amplifier.” One of these heat-pipes is intended to receive the standard platinum resistance thermometer (SPRT), and so must have an operating temperature range which can ensure stability of the SPRT. The BNM-INM decided to test a heat-pipe filled with dodecane. The effect of impurities on the thermal characteristics of a dodecane heat-pipe has been studied using two samples (99 % and 99.8 % purity). A significant improvement has been observed using the purest dodecane. The dodecane vapour pressure curve has been determined between 190 °C and 260 °C with an expanded uncertainty of about 16 mK. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

47. Liquid-Vapor Transitions in Mercury and Sodium Gas-Controlled Heat-Pipes.

Author

Merlone, A., Marcarino, P., Dematteis, R., Renaot, E., Elgourdou, M., and Bonnier, G.

Subjects
MERCURY (Element), VAPOR-liquid equilibrium, HEAT pipes, PHASE transitions
Abstract

The liquid-vapor transitions have been studied of pure mercury between 240 °C and 400 °C and of pure sodium between 660 °C and 960 °C. The phase transitions are realized at IMGC by means of gas controlled heat-pipes, all connected to the same, very accurate, pressure control system. This control uses an SPRT as the sensor and allows the study of the phase transitions at the level of a few tenths of a millikelvin. For the mercury phase transition, an agreement within a few tenths of a millikelvin could be reached between the temperature immersion profiles and the Clausius-Clapeyron curve. These temperature profiles have been obtained with the pressure control compensating the small pressure changes due to the ratio change in vapor and liquid amounts during movement of the thermometer in the thermometer well. In co-operation between IMGC and BNM-INM/CNAM, a study has been carried out on the sodium phase transition, as obtained in two different heat-pipes, one from IMGC and the other from INM. The temperature values in the two heat-pipes connected to the same pressure line are compared, as well as their temperature profiles. The effects of the sodium purity, the capillary structure and the heaters on these measurements have been studied. The sodium previously contained in the INM heat-pipe has been replaced with new sodium of 99.95 % purity. The capillary structure of the same heat-pipe has been improved, and an extra heater mounted on the bottom. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results