2005 5th: Bratislava
5th IATP Meeting
Bratislava. 9 September 2005

Program in .pdf format

The meeting was opened by the Chairman, Prof. W.A. Wakeham, who welcomed all present and thanked Prof. Libor Vozar for the arrangements made as the local organiser of the meeting. The Chairman also thanked all presents for attending the meeting, which meant staying an extra day. Apologies were presented on behalf of the secretary, Prof. Marc Assael, as he could not be present. Minutes were kept by Prof. C.M.B.P. Oliveira.
The meeting was divided into the usual scientific session and a business session. The proceedings are recorded here in that order.


2.1. New Transient Hot-Bridge Sensor to measure thermal conductivity
U. Hammerschmidt, V. Meier, R. Model (Germany)
The transient hot sensor as well as the model used to measure and calculate the thermal conductivity of solids was described in some detail.

2.2. Molecular Structural Dependence on some Lubricating Properties of Pentaerythritol esters
A. S. Pensado, M.J.P. Comunas, L. Lugo and J. Fernandez (Spain)
Viscosity measurements performed with a rolling ball viscometer as a function of temperature and pressure were presented. The effect of structure on the viscosity was also examined. The dependence of the viscosity of Pentaerythritol esters as a function of the structure of the lateral groups was made the subject of a particular study. In this case the viscosity increases as the lateral groups became more branched or lengthen. During discussion of these high viscosity fluids the need for a high viscosity standard was mentioned. Prof. Fernandez emphasised the fact that there are few experimental data as a function of pressure for viscous fluids that could be used as reference data.

2.3. High Pressure Viscosities, Conductivities and Ionic Diffusion Coefficients for liquid Butylmethyl-imidazolium salts
K.R. Harris, M. Kanakubo, L. A. Woolf (Australia)
Prof. Harris presented some of the work that he has carried out on the measurement of the transport properties of ionic liquids.

2.4. On the viscosity of HFC liquid mixtures
H.M.N.T. Avelino, J.M.N.A. Fareleira, C.M.B.P. Oliveira (Portugal)
Prof. Fareleira postulated a correlation for the viscosity of HFC fluids and mixtures based upon an extension of a hard sphere correlation

2.5. Viscous Properties of Ferrofluids
S. Will, J. Patzke and B. Rathke (Germany)
A very interesting presentation was given on the viscous properties of a new group of materials called ferrofluids, defined as suspensions in liquids formed by dispersions of small (nanometer scale) ferromagnetic particles coated with surfactant. He has also showed some examples of the numerous applications, in the medical field and in mechanical engineering. The approach for the investigation of magnetoviscous properties of ferrofluids by a combination of dynamic light scattering techniques and problems in the interpretation of initial results were presented

2.6. Viscosity and Surface Tension of high-Viscosity Fluids from Surface Light Scattering (SLS).
A.P. Froeba, C. Botero, A. Leipertz (Germany)
A new set of accurate absolute measurements performed, by the surface light scattering technique, on DIDP was presented. The reasons for some of the previous discrepancies were identified and a new set of results has been presented. The main difference in the results resides in the way the sample was handled. Dr. Froebe also showed the good agreement between data on the viscosity of DIDP from different laboratories using different experimental methods

2.7. Flow properties and behaviour of fresh concretes under pressures
K. Yucel (Turkey)
Some interesting results on the behaviour of fresh concretes were presented.

Each presentation engendered discussion and a few points of special interest are noted here:
Item 2.4. Several colleagues expressed concern at the patricular means that had been used to extend the hard-sphere representation of the viscosity of polar substances. The use of the dipole moment as a further parameter was a reasonable move but should be reflected perhaps in the volume parameter rather than the roughness, which was the contact component. The dipole moment could then be introduced before all steps in the hard sphere representation had been completed.
Item 2.5. Aside form the intrinsic interest in the ferro particles described by the speaker, answering the chairman, Prof. Will pointed out that these particles (a few nanometers) were available commercially already stabilised in a way that worked and they could be shipped. The chairman undertook to relay this information to Prof. M.J. Assael because the materials might be of use in the controversial issue of the thermal conductivity enhancement in nanofluids.
Item 2.6. The work of Dr A. Froebe, Ms C. Botero and Prof. A. Leipertz had shown the limits in the viscosity for their surface wave light-scattering technique. Dr Froeba explained the limits and the search for very small versions of the instrument.


The following projects were discussed:

1.Recommended Values of the Viscosity of Molten Iron and Aluminium
M.J. Assael (Greece), W.A. Wakeham, J. Redgrove, P. Quested, K. Mills (UK), I. Egry (Germany), A. Nagashima, Y. Sato (Japan), M. Bannish (USA)
Prof. Wakeham informed the members that the project has been concluded and a paper was submitted to Journal of Physical and Chemical Reference Data.

The following projects were discussed and it was agreed to continue them:

2. Viscosity and Thermal Conductivity of Water & Steam
M.J. Assael (Greece), E. Vogel, J. Millat (Germany), A. Nagashima (Japan), D. Friend, J.V. Sengers (USA)
Prof. Vogel informed IATP that the measurements he performed at low density were included in the correlation developed.
A draft paper was presented at the IAPWS meeting in Santorini Island in July 2005 and approved. Following established procedure the proposed equation is currently at the Evaluation Committee of IAPWS in order to be finally checked. After that, a paper will be written and circulated before submission.

3. Investigation of a New High-Viscosity Standard
J.M.N.A. Fareleira, C.M.B.P. Oliveira (Portugal), M.J. Assael (Greece), A. Leipertz, H. Bauer (Germany), A. Nagashima (Japan)
Prof. Fareleira presented a review of existing data on the viscosity of DIDP from last year and updated it with the new results of Froebe et al. One of the important parts of the discussion was that it was now understood that IATP sought to devise a standard reference viscosity associated with a fluid to an accuracy of about 1%. This, it was agreed, would be a valuable step for industrial use although it would not conform to the laboratory’s definition of a standard. Dr H. Bauer, although he accepted the stated accuracy mentioned for the viscosity, stressed that the chemical characterisation of the proposed material (DIDP) is the key issue. It was important to demonstrate whether material from different suppliers with the same nominal characterisation had the same viscosity within a defined limit. It was also emphasised that it would be necessary to trace the manufacturers of the material through each supplier to ensure they did not originate from the same producer. Dr H. Bauer undertook to explore this task with Merck in Germany. Prof. Harris would explore US and Japanese suppliers.
It was agreed that:
- Some more measurements should be performed by different Laboratories and methods and on different samples from several suppliers. Prof. Harris (Australia), Dr. Bauer (PTB), Prof. Trusler (London), Dr. Froeba (Germany) and Prof. Fareleira (Portugal) will be performing some more measurements.
- Surface tension effects upon viscosity measurements with routine viscometers should not be neglected and the surface tension of liquids proposed as reference materials should also be included in the definition of the standard.
- All the information will be lodged with Prof. Fareleira (Portugal).
- At the next meeting there should be a decision on the standard reference value, its associated undertainty and the ability to make a clear statement about the issues of characterisation.

4. On the Book on The Properties of Water, Air and Sea Water
A. Nagashima (Japan), M.J. Assael (Greece), J. Millat (Germany).
Except for the work on the properties of Air it was believed that all the work has been done. IATP will ask Dr Millat whether he is able to carry on the work. If he can not IATP should, find another way of proceeding so as to expedite the project which is significance now. Prof Vogel would contact Dr Millat for this purpose.

5. Feasibility study on Properties of Ionic Fluids
K. Marsh (New Zealand), A. Padua (France), J. Fareleira (Portugal)
IATP was informed that some work around this subject had been presented by Prof. Marsh at a recent Conference in Portugal. IATP should contact K. Marsh in order to find out if there is any need for IATP to intervene at this stage and whether the matter should stay as a live project for IATP or is being handled another way.

6. Viscosity of D2O
M.J. Assael (Greece), J. Millat (Germany), A. Nagashima (Japan), D. Friend, J.V. Sengers (USA)
Project continues in cooperation with IAPWS. Following the conclusion of the H2O viscosity equation, attention is focused on the thermal conductivity equation, while at the same time the D2O viscosity equation is examined.

7. Preliminary Investigation for Recommended values for Viscosity and Density of Molten metals and salts.
M.J. Assael (Greece), Y Sato (Japan)
At this stage it was not possible to decide whether the project should continue. Some interest has been demonstrated in the results especially for Cu and Zn. Although most of the data have been collected it is necessary to perform a great amount of work on data analysis. Furthermore Prof Sato suggested that owing to the high vapour pressure for Zinc there might be less data than for some metals and that, new measurements might be needed.

No changes.

The following dates and places of the IATP meetings were decided

5.1. IATP Meeting in 2006
The 2006 meeting of IATP will take place in Boulder (USA) in August prior to the 17th Thermophysical Properties Conference. This was a decision after debate about the relative merits of the location of the conference relative to its date in early August, which was inconvenient for Japanese and European scientists.

5.2. IATP Meeting in 2007
Turkish colleagues invited the 2007 meeting of IATP to take place in Istanbul, Turkey. The group expressed gratitude for the invitation but reserved final judgment until 2006. Prof. K.Yucel agreed that this allowed him time to plan everything.

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