24th IATP Meeting, June 21st 2026
The meeting was opened by the Chairman, Prof. Sir William Wakeham, who welcomed all present and thanked Silvia Lasala, as the local organiser of the meeting, for the excellent arrangements.
The meeting was divided into the usual scientific session and business session. The proceedings are recorded here in that order.
2. SCIENTIFIC SESSION
Each presentation engendered discussion and a few points of special interest are noted here:
2.1 Diffusivities in Electrolyte Mixtures
Chathura Kankanamge, Tobias Klein, and Andreas Paul Fröba (Germany)
The lecture presented AOT-TP diffusivity studies on various electrolyte systems using Dynamic Light Scattering and molecular dynamics simulations, highlighting binary mixtures of [Li][NTf2] and ACN.
2.2 Towards Advanced Thermodynamic Cycles: Modelling the Thermophysical Properties of Reactive Working
Fluids
Julien Joliat, Rachid Hadjadj, Luis Pinilla Monsa-lve, Olivier Herbinet, Silvia Lasala (France)
S. Lasala discussed her laboratory's work on using reactive working fluids in advanced thermodynamic cycles to achieve higher efficiencies. Motivated by promising preliminary models, the team screened approximately 500 candidates based on dimerization reactions. By calculating their thermodynamic properties, they narrowed the field to about 50 stable fluids. Preliminary results for the N₂O₄⇌ 2NO₂ reaction were presented.
2.3 Transport Properties of Binary Gas Mixtures of H2 with N2, O2, CO2, H2S, and H2O from First Principles
Robert Hellmann (Germany)
R. Hellmann discussed the derivation of a potential energy surface from quantum-chemical principles to calculate transport properties. Utilizing kinetic theory and ab initio calculations, he also presented dilute-gas transport properties—focusing on diffusion coefficients and viscosity—across several systems, including N₂-H₂, O₂-H₂, dry air-H₂, CO₂-H₂, and H₂O-H₂.
2.4 Viscosity Modeling Using the Friction Theory in Conjunction with the Reverse van der Waals EOS
Sergio E. Quiñones Cisneros, and Jianxin Wang (Germany)
New advances in calculating the viscosity coefficient using the Friction Theory in conjunction with the reverse van der Waals EOS were presented; their goal being the development of a generalized model for fluids of industrial interest.
2.5 Vibrating-Wire Viscometer for Cryogenic Liquid Mixtures
P. Eckmann, Xiaoxian Yang (Germany), J.P. Martin Trusler (UK), and Markus Richter (Germany)
X. Yang presented their new vibrating wire instrument for the measurement of the viscosity of major gas components (methane, ethane and propane, and their mixtures. Viscosity measurements of these components and their mixtures were also shown.
2.6 Development of a High-Pressure, High-Temperature Phase Behavior Apparatus for the Study of
Asymmetric Mixtures
Aaron Rowane (USA)
Asymmetric mixtures feature components with vastly different volatilities, molecular weights, or interactions. A. Rowane introduced a novel instrument designed to evaluate such systems at pressures up to 240 MPa and temperatures up to 400°C, detailing the operational challenges addressed during its development.
2.7 A Greenspan Acoustic Viscometer for Measurements on Semiconductor Gases
Karim Al-Barghouti and Mark O. McLinden (USA)
The design of a Greenspan Acoustic viscometer mostly for toxic or corrosive gases was presented by K. Al-Barghouti. Preliminary measurements were shown.
2.8 Thermal Conductivity and Emissivity of Materials for Space Applications,
Hans-Peter Ebert, and Jochen Manara (Germany)
Because spacecraft face extreme temperature variations—from cryogenic lows to highs exceeding 5500°C during reentry—characterizing solid material properties over wide temperature ranges is essential. H.-P. Ebert demonstrated this need across several aerospace applications they dealt with: 1) measuring the high-temperature thermal conductivity of the support structures of the solar panels for the sun-facing BepiColombo Mercury probe; 2) characterizing insulation down to 15 K for Ariane 6's cryogenic H₂ and O₂ vessels; 3) testing materials between 200 K and 20 K to shield the ESA Herschel Space Observatory; and 4) developing rigid, carbon-xerogel insulation (TRL 7) to withstand temperatures up to 2500°C..
2.9 Viscosity Measurement at Temperatures Down to 90 K Based on Vibrating-wire Method
Xianyang Meng, Jiangtao Wu, Xinzhi Zhou, Huanxu Ji (China)
J. Wu discussed the lack of thermophysical property data for hydrogen-enriched natural gas (H2NG), contrasting with the abundant data available for CH₄, C2H6, C3H8, N₂, and Ar above 150 K. To address this gap, they employed capillary, oscillating, and vibrating-wire viscometers. J. Wu detailed a newly developed vibrating-wire instrument—utilizing a 50 µm tungsten wire and supports—and presented viscosity measurements for N₂, Ar, CH₄, C2H6, C3H8, and air from 90 K to 250 K across gas, liquid, and supercritical states.
2.10 Insights into Thermophysical Properties of Ionic Liquid Phase from CALPHAD Methodology.
Rui Zhang, Lina Kjellqvist, Huahai Mao, Reza Naraghi, Qing Chen (Sweden)
R. Zhang introduced the CALPHAD software for calculating phase diagrams and predicting a comprehensive suite of thermochemical, thermophysical, kinetic, mechanical, and equilibrium properties. Highlighting an integrated ionic two-sublattice liquid model, the presentation also featured viscosity diagrams for oxide liquid systems, molten salts, and higher-order systems.
2.11 When Materials Behaviour Dominate Measurements – The High Temperature Syndrome
Carlos A. Nieto deCastro, Maria José Lourenço, João Chainho,Mafalda Gil, Pedro Rodrigues (Portugal)
Highlighting the viability of concentrated solar power for energy storage, M.J. Lourenço discussed molten salts, the current availability of thermophysical property data, and the inherent challenges in performing accurate measurements.
2.12 Isotope Fractionation by Mass diffusion: From Molecular Simulations to Modelling.
Hai Hoang, Maxime Enrico, Romain Vermorel, Anne Battani, Magali Pujol, Guillaume Galliéro (France)
G. Galliéro reviewed current tracer fractionation modeling, focusing on molecular simulations of noble gas diffusion in geophysical contexts. While assuming elemental diffusion is proportional to the square root of the masses works for modeling noble gases in n-C₆H₁₄, it is ineffective for isotopes. Furthermore, he demonstrated that benzene fractionation driven by isotope diffusion is negligible.
2.13 New Public Services from the Thermodynamics Research Center (NIST)
Ala Bazyleva, Vladimir Diky (USA)
A. Bazyleva presented the activities of the NIST Thermodynamic Research Center TRC). She particularly emphasized the scope of the TRC property database, the ThermoData Engine, the ThermoLit and ThermoPlan, and showed the free access to the TRC public data. The presentation included a demonstration of 1) public TDE, 2) a review support application, and 3) a research challenges service. Her presentation will be distributed to the those who were present.
2.14 Measurement and Prediction of Diffusion Coefficients for High-Pressure Binary Gas Mixtures
Minzhen Li,Sam Kobeissi, Michael L. Johns, Eric F. May (Australia)
M. Li shared new PGSE-NMR intradiffusion measurements for CH₄+H₂ mixtures at 28 °C across pressures of 6, 100, and 150 bar. In addition to outlining the instrumentation and the procedures used to calculate the intradiffusion and Maxwell-Stefan diffusion coefficients, the presentation also highlighted the use of the ThermoFAST diffusion calculation software.
2.15 Accurate Determination of Viscosity and Interfacial Tension in the Presence of Line-Broadening Effects
by Surface Light Scattering
Pedro S. Martínez-González, Johannes Knorr, Andreas Paul Fröba (Germany).
P.S. Martinez-González introduced a supplementary Monte Carlo simulation approach for data analysis, successfully calculating the high-temperature viscosity and surface tension of toluene with under 2% uncertainty.
3. BUSINESS SESSION
3.1. PROJECTS CONCLUDED
1. Thermal Conductivity and Enthalpy of Fusion of n-Alkanes as Practical PCM
L. Fedele (Leader), S. Bobbo (Italy), M.J. Assael (Greece), W.A. Wakeham (U.K.), M.L. Huber, R. Perkins (USA), A.P. Fröba, T.M. Koller, K. Meier, B. Rathke, S.E. Quiñones-Cisneros (Germany), J.M.N.A. Fareleira, F.J.P. Caetano (Portugal), J. Fernandez (Spain), E. May (Australia), V. Shevtsova (Belgium), V. Diky (USA)
Project concluded.
3.2. PROJECTS CONTINUED
The following projects were discussed, and it was agreed to continue them:
1. Reference Correlations for the Viscosity and Thermal Conductivity of Fluids over Extended Temperature and Pressure Ranges.
M.J. Assael (Greece), M.L. Huber, R.A. Perkins (USA), F. Caetano, J.M.N.A. Fareleira (Portugal)
This is an on-going project on developing new reference correlations of the viscosity and thermal conductivity of fluids. M.J. Assael pointed out that new recent ab-intio calculations carried out by R. Hellmann allow the incorporation of a much more accurate dilute-gas correlation for the transport properties that is capable of excellent prediction at high temperatures. Project continues.
2. Further Understanding of the Operation of the Torsional Crystal Viscometer
C.A. Nieto de Castro, F.J.V. Santos (Portugal), W.A. Wakeham (UK)
Project continues but awaits more experimental input.
3. Transport of Hydrogen in Liquids
J.M.P. Trusler (UK), T.M. Koller, M.H. Rausch, A.P. Fröba, B. Rathke (Germany), F. Caetano, J.M.N.A. Fareleira (Portugal)
The project continues narrowed down to only liquids. A review article will be written at some stage.
4. Apparent Thermal Conductivity of Nanofluids
J. Fernandez (Spain) L. Fedele (Italy), C.A. Nieto de Castro, Maria José Lourenço (Portugal), A.P. Fröba (Leader), T.M. Koller (Germany), M. Buchmann (Germany)
Project continues. The possibility of a round study on a reference nanofluid based on glycerol with dispersed cerium oxide nanoparticles will be examined.
5. Towards a Definition of “Ideal-Solution” for Transport Properties.
C.A. Nieto de Castro (Portugal), G. Guevara Carrion (Germany)…
Project continues.
3.3. NEW COLLABORATIVE PROJECTS
Ideas for new projects were discussed briefly but are awaiting better formulation.
1. Transport properties for reactive mixtures of fluids.
S. Lasala (Leader, France), Andreas P. Fröba, X. Yang (Germany), L. Fedele, S. Bobbo, D. Menegazzo (Italy), H.P. Ebert (Germany), T. Vlugt (Netherlands).
In the first phase, to investigate the literature for the information that currently exists and what might be needed.
3.4. PROCEDURE FOR IATP ENDORSEMENT
Members were reminded that if they wish to have the endorsement of IATP for their work in their publication, they should submit it to the Secretary in the first instance to arrange a rapid review. Referees who have agreed to participate in the review process in addition to the Executive Members are M.L. Huber and E. May.
4. MEMBERSHIP
M.J. Assael reminded everyone that all information about IATP activities, as well as the current list of members, can always be found at
https://ltpep.com/ -> I.A.T.P.
It was also decided that members who had not attended for some time, and where there was evidence that they would probably not have a continuing connection, would be removed from the list.
The criterion to become a Member of IATP is to be present to at least two meetings. Having checked the list of attendees of the last three meetings, the following were approved as Members:
- Dr Ala Bazyleva
- Mr Patrick Schmidt.
5. FUTURE MEETINGS
5.1. 25thIATP Meeting, 2027
The 25th IATP Meeting will take place in Hannover, Germany, in September 2027. Markus Richter will be the local host. More details in due course.
5.1. 26th IATP Meeting, 2028
For the 26th IATP Meeting possible places discussed were Padova (L. Fedele), or Hamburg (K. Meier). Details will be announced in due course
6. LIST OF ATTENDEES
List of people that attended the meeting:
1. Professor Sir William A. Wakeham (Chairman)
2. Professor Marc J. Assael (Secretary)
3. Professor Andreas P. Fröba
4. Professor Carlos Nieto de Castro
5. Professor J.P. Martin Trusler
6. Professor Jiangtao Wu
7. Professor Ilmutdin Abdulagatov
8. Mr Karim Al-Barghout
9. Dr Ala Bazyleva
10. Mr Hubert P. Blabus
11. Mr João Chainho
12. Mr Pranay Kumal Chittern
13. Dr Vladimir Diky
14. Dr Hans-Peter Ebert
15. Dr Laura Fedele
16. Professor Josefa Fernandez
17. Professor Guillaume Galliero
18. Ms Sukrati Gupta
19. Dr Robert Hellmann
20. Mr Huanxu Ji
21. Mr Chathura Jayan Kamkanamge
22. Dr Tobias Klein
23. Professor Thomas M. Koller
24. Dr Silvia Lasala
25. Professor Maria José V. Lourenço
26. Dr Philipp Marienhagen
27. Mr Pedro Martinez-Gonzalez
28. Professor Eric May
29. Professor Karsten Meier
30. Mr Davide Menegazzo
31. Professor Sergio E. Quiñones Cisneros
32. Dr Michael Rausch
33. Professor Markus Richter
34. Dr Pedro C.R. Rodrigues
35. Dr Aaron Rowane
36. Mr Kisal Randoola Senadeera
37. Mr Patrick Schmidt
38. Ms Yang Yang
39. Ms Yilun Yang
40. Dr. Xiaoxian Yang
41. Mr Yongzhen Sun
42. Ms Ziwen Zhai
43. Dr Rui Zhang
