Consultative Committee for Thermometry CCT Dr Yuning DUAN CCT - - PowerPoint PPT Presentation

Consultative Committee for Thermometry ‐ CCT

Dr Yuning DUAN CCT President and CIPM member (NIM – China) 25th meeting of the CGPM

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• Temperature
• Primary thermometry
• Temperature scales
• Fixed points and interpolation equations
• Thermodynamic temperature

→ new definion of the kelvin

• Secondary contact thermometry
• Humidity
• Thermophysical quantities
• CCT meetings in 2012 and 2014
• Next meeting planned for 2017

Main Areas

Consultative Committee for Thermometry / Dr Yuning DUAN

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• High‐accuracy determination of the Boltzmann constant using

different techniques in view of a new definition of the kelvin

• Ensure world‐wide equivalence of temperature in a mixed

situation of ITS‐90 and thermodynamic temperature primary standards

• Anticipating a new temperature scale
• Give support to climate studies
• Thermal imaging
• Expanding activities in humidity world wide. Towards a universal definition
• f humidity quantities and measurands (traceable to the SI)
• Challenge to investigate thermophysical measurements to support climate

and energy sectors, and to identify reference materials

Areas of priority and potential

Consultative Committee for Thermometry / Dr Yuning DUAN

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• High‐accuracy determination of the Boltzmann constant using

different techniques in view of a new definition of the kelvin

• Ensure world‐wide equivalence of temperature in a mixed

situation of ITS‐90 and thermodynamic temperature primary standards

• Anticipating a new temperature scale
• Give support to climate studies
• Thermal imaging
• Expanding activities in humidity world wide. Towards a universal definition
• f humidity quantities and measurands (traceable to the SI)
• Challenge to investigate thermophysical measurements to support climate

and energy sectors, and to identify reference materials

Areas of priority and potential

Consultative Committee for Thermometry / Dr Yuning DUAN

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Towards a new definition of the kelvin

Consultative Committee for Thermometry / Dr Yuning DUAN

• Progress on the determination of the Boltzmann constant

for a future re‐definition of the kelvin using different methods

p =kT 0 (r ‐ 1)/0 u0

2 =  kT / m 

= cp/cV

<U 2> = 4 kT R  D = [2 kT /(mc0

2)]1/20

Acoustic Gas Thermometry Dielectric Constant Gas Thermometry Johnson Noise Thermometry Doppler Broadening Thermometry

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Towards a new definition of the kelvin

Consultative Committee for Thermometry / Dr Yuning DUAN

Values considered by CODATA in 2013 (extract) recommends that a fixed numerical value of the Boltzmann constant will be adopted, when the following two conditions are met:

• the relative standard uncertainty of the

adjusted value of k is less than 1 × 10−6;

• the determination of k is based on at

least two fundamentally different methods, of which at least one result for each shall have a relative standard uncertainty less than 3 × 10−6. Recommendation T 1 (2014) to the CIPM:

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Towards a new definition of the kelvin

Consultative Committee for Thermometry / Dr Yuning DUAN

Values considered by CODATA in 2013 (extract) recommends that a fixed numerical value of the Boltzmann constant will be adopted, when the following two conditions are met:

• the relative standard uncertainty of the

adjusted value of k is less than 1 × 10−6;

• the determination of k is based on at

least two fundamentally different methods, of which at least one result for each shall have a relative standard uncertainty less than 3 × 10−6. Recommendation T 1 (2014) to the CIPM:

k = 1.380...10‐23 J/K ... at the next CGPM

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• NMIs and DIs, themselves precursor to other stakeholders
• International Association on Properties of Water and Steam (IAPWS)
• International Surface Temperature Initiative
• International Union of Pure and Applied Chemistry (IUPAC)
• International Confederation for Thermal Analysis and Calorimetry (ICTAC)
• International Association of Chemical Thermodynamics (IACT)
• World Meteorological Organisation (WMO):
• WMO‐CIMO (Commission for Instruments and Methods of Observation)
• WMO GCOS‐GRUAN (Global Climate Observing System –

Reference Upper‐Air Network)

Stakeholder involvement

Consultative Committee for Thermometry / Dr Yuning DUAN

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• MEMBERSHIP INMETRO (Brazil) member and CMI (Czech Republic) , HMI/FSB‐LPM

(Croatia) observers

• CCT strategy drafted in 2012 following the BIPM time schedule
• Reduced number of WGs from 10 to 6
• …shorter term projects covered by Task Groups; wider exchange in Forum format
• Strengthened WG‐KC – guarantees quality and validity of published data
• Created a Task Group on Environment
• RMO TC Chairs invited to the CCT 2014 and selected WG meetings
• Drafted Mise en Pratique to anticipate the new definition of the kelvin
• Launched 2 CCT comparisons (radiation thermometry and SPR Thermometers)
• CCT‐K6 in humidity completed
• Initiated exchange with the WMO‐CIMO
• Launched monthly internal news letters

Achievements 2011 ‐ 2014

Consultative Committee for Thermometry / Dr Yuning DUAN

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• Encourage result oriented groups
• Improved exchange with international stakeholders
• Prepare the new definition of the kelvin
• Solid international basis for the determination of the Boltzmann constant
• Close contact with CODATA
• Guidance on the Realization of the ITS‐90
• Long‐term work towards a new temperature scale
• Review of the CIPM‐MRA from the CCT perspective
• Study impact of the new GUM ‐ Guide to the Expression of Uncertainty in

Measurement from the CCT perspective

• Continued guidance for secondary thermometry
• Identify how to best contribute to environmental and climate issues
• CCT strategy will be reviewed by 2017

Future Strategy

Consultative Committee for Thermometry / Dr Yuning DUAN

Thank you

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• Temperature issues involved in ALL areas of high precision

metrology

• Thermometry and amount of substance

–to determine the Boltzmann constant via the speed of sound –or dielectric gas constant

Thermometry and photometry

–spectral emissivity for solar thermal measurements

Humidity and chemistry

–linked to traces of water in gas and moisture

in materials

Humidity, temperature and global warming

Interdisciplinary issues

Consultative Committee for Thermometry / Dr Yuning DUAN