Tag Archives: National Physical Laboratory

Water’s liquid-vapour interface

The UK’s National Physical Laboratory (NPL), along with IBM and the University of Edinburgh, has developed a new quantum model for understanding water’s liquid-vapour interface according to an April 20, 2015 news item on Nanowerk,

The National Physical Laboratory (NPL), the UK’s National Measurement Institute in collaboration with IBM and the University of Edinburgh, has used a new quantum model to reveal the molecular structure of water’s liquid surface.

The liquid-vapour interface of water is one of the most common of all heterogeneous (or non-uniform) environments. Understanding its molecular structure will provide insight into complex biochemical interactions underpinning many biological processes. But experimental measurements of the molecular structure of water’s surface are challenging, and currently competing models predict various different arrangements.

An April 20, 2015 NPL press release on EurekAlert, which originated the news item, describes the model and research in more detail,

The model is based on a single charged particle, the quantum Drude oscillator (QDO), which mimics the way the electrons of a real water molecule fluctuate and respond to their environment. This simplified representation retains interactions not normally accessible in classical models and accurately captures the properties of liquid water.

In new research, published in a featured article in the journal Physical Chemistry Chemical Physics, the team used the QDO model to determine the molecular structure of water’s liquid surface. The results provide new insight into the hydrogen-bonding topology at the interface, which is responsible for the unusually high surface tension of water.

This is the first time the QDO model of water has been applied to the liquid-vapour interface. The results enabled the researchers to identify the intrinsic asymmetry of hydrogen bonds as the mechanism responsible for the surface’s molecular orientation. The model was also capable of predicting the temperature dependence of the surface tension with remarkable accuracy – to within 1 % of experimental values.

Coupled with earlier work on bulk water, this result demonstrates the exceptional transferability of the QDO approach and offers a promising new platform for molecular exploration of condensed matter.

Here’s a link to and a citation for the paper,

Hydrogen bonding and molecular orientation at the liquid–vapour interface of water by Flaviu S. Cipcigan, Vlad P. Sokhan, Andrew P. Jones, Jason Crain and Glenn J. Martyna.  Phys. Chem. Chem. Phys., 2015,17, 8660-8669 DOI: 10.1039/C4CP05506C First published online 17 Feb 2015

The paper is open access although you do need to register on the site provided you don’t have some other means of accessing the paper.

Wilkinson Prize for numerical software: call for 2015 submissions

The Wilkinson Prize is not meant to recognize a nice, shiny new algorithm, rather it’s meant for the implementation phase and, as anyone who have ever been involved in that phase of a project can tell you, that phase is often sadly neglected. So, bravo for the Wilkinson Prize!

From the March 27, 2014 Numerical Algorithms Group (NAG) news release, here’s a brief history of the Wilkinson Prize,

Every four years the Numerical Algorithms Group (NAG), the National Physical Laboratory (NPL) and Argonne National Laboratory award the prestigious Wilkinson Prize in honour of the outstanding contributions of Dr James Hardy Wilkinson to the field of numerical software. The next Wilkinson Prize will be awarded at the [2015] International Congress on Industrial and Applied Mathematics in Beijing, and will consist of a $3000 cash prize.

NAG, NPL [UK National Physical Laboratory] and Argonne [US Dept. of Energy, Argonne National Laboratory] are committed to encouraging innovative, insightful and original work in numerical software in the same way that Wilkinson inspired many throughout his career. Wilkinson worked on the Automatic Computing Engine (ACE) while at NPL and later authored numerous papers on his speciality, numerical analysis. He also authored many of the routines for matrix computation in the early marks of the NAG Library.

The most recent Wilkinson Prize was awarded in 2011 to Andreas Waechter and Carl D. Laird for IPOPT. Commenting on winning the Wilkinson Prize Carl D. Laird, Associate Professor at the School of Chemical Engineering, Purdue University, said “I love writing software, and working with Andreas on IPOPT was a highlight of my career. From the beginning, our goal was to produce great software that would be used by other researchers and provide solutions to real engineering and scientific problems.

The Wilkinson Prize is one of the few awards that recognises the importance of implementation – that you need more than a great algorithm to produce high-impact numerical software. It rewards the tremendous effort required to ensure reliability, efficiency, and usability of the software.

Here’s more about the prize (list of previous winners, eligibility, etc.), from the Wilkinson Prize for Numerical Software call for submissions webpage,

Previous Prize winners:

  • 2011: Andreas Waechter and Carl D. Laird for Ipopt
  • 2007: Wolfgang Bangerth for deal.II
  • 2003: Jonathan Shewchuch for Triangle
  • 1999: Matteo Frigo and Steven Johnson for FFTW.
  • 1995: Chris Bischof and Alan Carle for ADIFOR 2.0.
  • 1991: Linda Petzold for DASSL.


The prize will be awarded to the authors of an outstanding piece of numerical software, or to individuals who have made an outstanding contribution to an existing piece of numerical software. In the latter case applicants must clearly be able to distinguish their personal contribution and to have that contribution authenticated, and the submission must be written in terms of that personal contribution and not of the software as a whole. To encourage researchers in the earlier stages of their career all applicants must be at most 40 years of age on January 1, 2014.
Rules for Submission

Each entry must contain the following:

Software written in a widely available high-level programming language.
A two-page summary of the main features of the algorithm and software implementation.
A paper describing the algorithm and the software implementation. The paper should give an analysis of the algorithm and indicate any special programming features.
Documentation of the software which describes its purpose and method of use.
Examples of use of the software, including a test program and data.


The preferred format for submissions is a gzipped, tar archive or a zip file. Please contact us if you would like to use a different submission mechanism. Submissions should include a README file describing the contents of the archive and scripts for executing the test programs. Submissions can be sent by email to [email protected]. Contact this address for further information.

The closing date for submissions is July 1, 2014.

Good luck to you all!

‘Silverized’ clothing and wearable electronics

A July 30, 2013 news item on ScienceDaily features a technique for printing silver directly onto fibres,

Scientists at the National Physical Laboratory (NPL), the UK’s National Measurement Institute, have developed a way to print silver directly onto fibres. This new technique could make integrating electronics into all types of clothing simple and practical. This has many potential applications in sports, health, medicine, consumer electronics and fashion.

Most current plans for wearable electronics require weaving conductive materials into fabrics, which offer limited flexibility and can only be achieved when integrated into the design of the clothing from the start. [emphasis mine] NPL’s technique could allow lightweight circuits to be printed directly onto complete garments.

The July 30, 2013 National Physical Laboratory news release on EurekAlert, which originated the news item, provides a little more detail,

Silver coated fibres created using this technique are flexible and stretchable, meaning circuits can be easily printed onto many different types of fabric, including wool which is knitted in tight loops.

The technique involves chemically bonding a nano‐silver layer onto individual fibres to a thickness of 20 nm. The conductive silver layer fully encapsulates fibres and has good adhesion and excellent conductivity.

The researchers don’t appear to have published a paper but there is a bit more information on the NPL’s Smart Textiles webpage,

At NPL the Electronics Interconnection group has developed a new method to produce conductive textiles. This new technique could make integrating electronics into all types of clothing simple and practical by enabling lightweight circuits to be printed directly onto complete garments.

The nano silver material is chemically bonded to the fabric, encapsulating the fibres and providing full coverage. The resulting textile demonstrates good adhesion, flexibility and is stretchable achieving excellent resistivity of 0.2 Ω/sq.

My May 9, 2012 posting concerns a project where batteries were being woven into textiles for the US military.

Honey, could you please unzip my electronics?

The UK’s National Physical Laboratory has been proceeding with an interesting project on reusable electronics, ReUSE (Reuseable, Unzippable, Sustainable Electronics), according to the Oct. 30, 2012 news item on Nanowerk,

The National Physical Laboratory (NPL), along with partners In2Tec Ltd (UK) and Gwent Electronic Materials Ltd, have developed a printed circuit board (PCB) whose components can be easily separated by immersion in hot water. …

The electronics industry has a waste problem – currently over 100 million electronic units are discarded annually in the UK alone, making it one of the fastest growing waste streams.


It was estimated in a DTI [Dept. of Trade and Industry]-funded report, that around 85% of all PCB scrap board waste goes to landfill. Around 70% of this being of non-metallic content with little opportunity for recycling. This amounts to around 1 million tonnes in the UK annually equivalent to 81 x HMS Belfasts [ships]

This revolutionary materials technology allows a staggering 90% of the original structure to be re-used. For comparison, less than 2% of traditional PCB material can be re-used. The developed technology lends itself readily to rigid, flexible and 3D structures, which will enable the electronics industry to pursue new design philosophies – with the emphasis on using less materials and improving sustainability.

Here’s a video demonstrating the technology, from the ReUSE project news page,

I had to look at this twice to confirm what I was seeing. (I worked for a company that manufactured circuit boards for its products and the idea of immersing one of those in hot water is pretty shocking to me [pun intended].)