King parrot
Stjepan Marčelja
Visiting Fellow, ANU
e-mail:
hydration force

Hydration forces and effective potentials

The December 2011 issue of Current Opinion in Colloid and Interface Forces contains a section dedicated to hydration forces.
My task was to review the use of effective potentials in problems involving charged interfaces. From many lines of evidence it follows that short-range interactions between charged surfaces involve two characteristic lengths, the range of the interaction and the spatial periodicity, both about 2.5 ± 0.5 Å.

This is illustrated above using the data from classical experiments by Pashley and Israelachvili.

Other related features that we studied over the years are mentioned on the double layer page.





The timescale and extent of thermal expansion of the global ocean due to climate change

With recently improved instrumental accuracy, the change in the heat content of the oceans and the corresponding contribution to the change of the sea level can be determined from in situ measurements of temperature variation with depth.
Nevertheless, it would be favourable if the same changes could be evaluated from just the sea surface temperatures because the record could then be extended into the past and projected into the future. We show that the average change in the heat content of the oceans and the corresponding contribution to a change in the sea level can be evaluated from the past sea surface temperatures. Volume expansion leads to 13 cm higher sea level with each degree of surface warming and the characteristic time is about 50 years. See more in a recent volume of open source journal Ocean Science.







  Split, Croatia
  2006-2010 I was a professor at the University
  of Split teaching during Spring semesters.


 

  During the three years 2002-2004 I was the
  director of this institute in Zagreb, Croatia.
  Some of my reports or newspaper articles
  from this period (in Croatian language) are
  available here.


Past work, general comments and references

 

In the past, I worked in superconducting thin films [1], liquid crystals [2], biological membranes [3], signals in the visual cortex [4], electrical double layers [5] and climate change [6]. Most interesting examples are shown in the pages of past work. I am interested in describing and understanding natural phenomena in quantitative terms, and always like to hear a new question or challenge. Find me at the ANU in Canberra or send an email.  

  1. S. Marčelja, W.E. Masker and R.D. Parks, Electrical conductivity of a two-dimensional superconductor, Physical Review Letters 22 (1969) 124-127.

  2. S. Marčelja, Chain ordering in liquid crystals. I. Even-odd effect, Journal of Chemical Physics 60 (1974) 3599-3604.

  3. S. Marčelja, Chain ordering in liquid crystals. II. Structure of bilayer membranes, Biochimica et Biophysica Acta 367 (1975) 165-176.

  4. S. Marčelja, Mathematical description of the responses of simple cortical cells, Journal of the Optical Society of America 70 (1980) 1297-1300.

  5. S. Marčelja, Exact description of electrical double layers, Langmuir 16 (2000) 6081-6083.

  6. S. Marčelja, The timescale and extent of thermal expansion of the global ocean due to climate change, Ocean Science 6, (2010) 179-184.

Updated 18/6/2011

-> to ANU Applied Maths Dept
-> to Aqueous double layers
-> to Past work