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CHPC student graduates with a doctorate in Physics

Cliffton Masedi, a CSIR Centre for High Performance Computing (CHPC) student, has graduated with a Doctor of Philosophy: Physics from the University of Limpopo.

Now formally addressed as Dr Cliffton Masedi, his thesis is titled: Computational Modelling Studies of Discharge Products of Advanced Lithium-Sulphur Batteries and was supervised by Professor Phuti Ngoepe (University of Limpopo) and co-supervised by Dr Happy Sithole (Director: Centre for High Performance Computing).

Cliffton was one of two PhD students supported by the CHPC, with the second candidate currently pursuing his through the University of Cape Town. He is excited about his future prospects and expresses deep gratitude to the CSIR and CHPC: “My three-year studentship covered 100% of my university fees, included a stipend, travelling allowances to beneficial workshops which included one in Germany where I needed to learn how to use a new component of the Media-UNCLE code called Cluster Extension and which was critical to my research”.

“I love the field and as it not so developed in South Africa means I can still grow and develop broad use of high performance computing”, said Dr Masedi.


Dr Cliffton Masedi’sthesis citation

Lithium sulphur (Li/S) and Li air (Li/O) batteries have a potential to provide two to five times the energy density of the current Lithium-ion battery systems. However, Li/S suffers from low conductivity of sulphur and the solubility of intermediary polysulfide species during cycling. Mixed sulphur-selinium (SxSey) represents an attractive new class of cathode materials with promising electrochemical performance in reactions with both lithium and sodium ions. Notably, unlike existing Li/S batteries that only operate at high temperature, these new Se and Li/SexSy electrodes are capable of room temperature cycling. Cliffton’s major contribution is employment of cluster expansion and Monte Carlo techniques to investigate phase separating behaviour of Li2S1-x-Sex.


His study predicted a phase diagram of such system and proposed a phase change at a relatively low temperature of 350K for Li2S0.5Se0.5. In the absence of associated experimental details on Li/SexSy systems, he invoked an unrelated simulation approach, classical molecular dynamics, for which he developed new models, to validate his results. The work provides valuable insights on where phase separation and mixed phases tend to occur in Li2S1-x-Sex systems, over an entire range of sulphur and selenium contents, which will guide designs of future experiments.

Clifftonhas presented 27 papers at local and international conferences and was awarded prizes for best PhD presentations at local conferences. He has published a paper on the work and two more papers have been prepared for publication.

Last Updated on Wednesday, 17 October 2018 10:34

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Student Cluster Competition team takes third place in Germany

A team of South African students has claimed third place at an international high performance computer competition in Frankfurt, Germany. The team of six, made up of Witwatersrand and Limpopo University undergraduate students were part of 12 teams from around the world who represented their countries in the prestigious supercomputing conference that took place from 25 to 27 June 2018. The team came third to two teams from China.

The competition consists of computer science and engineering students who showcase computing systems of their own design, adhere to strict power constraints and who must seek to achieve the highest performance across a series of standard high performance computing (HPC) benchmarks and applications.

South Africa has been participating in the international competition since 2013 and has won it in 2013, 2014 and 2016, coming second in 2015 and 2017 and is one of the few teams in the competition that is made-up of only undergraduate students and that sends different students each year.  During the competition, students build small HPC clusters on the exhibition floor from hardware provided by the Centre for High Performance Computing (CHPC), based at the CSIR, and its industrial partners.

The CHPC is an intervention by the Department of Science and Technology (DST), which is aimed at addressing the computational requirements of the wider scientific community in South Africa.

The South African team is made up of computer science and engineering students from Wits University: Meir Rosendorff, Joshua Bruton, Kimessha Paupamah, Katleho Mokoena, Nathan Michlo and Njabulo Sithole from the University of Limpopo.

“We are so excited to have been placed third in this competition, the competition was so tough, we were doing this for the first time but we managed to pull an ace,” said team members: Meir Rosendorff, Joshua Bruton and Kimessha Paupamah. They return to South Africa tomorrow evening and when asked what their plans for the remainder of their time in Germany were they said: “Now that the hard work is done, we plan to hire bicycles and cycle around Frankfurt and do touristy things”.

First place went to Tsinghua University from China and second to Shanghai Tech University also from China.

The CHPC’s director, Dr Happy Sithole, is ecstatic about team South Africa’s performance. “This is a significant achievement from South Africa as we bring a new team each year, whilst other teams repeat members and other teams even use postgraduate students. We are trying to make sure that we grow the numbers of students who get this exposure to this field of HPC. For the past six years we have had 36 students who have performed well on the world stage,” he said.

South African team representatives were selected from 10 participating teams at the national competition run in December 2017 during the CHPC’s national conference. Team selection for the national competition takes place at the centre’s Winter School which is designed to impart critical knowledge for building a cluster and includes using Linux systems, the basic software stack of a cluster and considerations which should be taken into account when choosing hardware. Team selection concludes with an assignment which requires each team to build a prototype cluster in the Cloud.

South African team representatives have gone through extensive training since joining the running for the international competition that started with the CHPC Winter School in Stellenbosch. After the national round of the competition in Pretoria, the team then  travelled to the Texas Advanced Computing Centre in Austin, America where they were trained by well experienced administrators of supercomputing clusters on design and administration of supercomputers.


Last Updated on Friday, 29 June 2018 12:35

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CHPC's Lengau cluster remains on Top500 List

The CHPC's Lengau supercomputer has placed  246th on the computing Top 500 List at the International Supercomputing Conference in Frankfurt, Germany in June 2018.

The Top 500 List lists computers ranked by their performance on the LINPACK benchmark (The LINPACK Benchmarks measure a system's floating point computing power. Introduced by Jack Dongarra, they measure how fast a computer solves a dense n by n system of linear equations, which is a common task in science and engineering). The list is announced in June and in November each year. With over 32000 cores, Lengau remains the fastest computer on the African continent owing to its speed of just over a petaflop. In the previous list, November 2017, Lengau placed at position 165.

Lengau continues to put the country in the company of leading supercomputing nations. It is the only system in Africa featuring on the TOP500 and is the second fastest supercomputer in the southern hemisphere, a demonstration of South Africa’s commitment to ensuring world-class services to its research community and industry.

Last Updated on Thursday, 28 June 2018 15:42

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CHPC joins DARA in Madagascar for the Linux and Python training

Centre for High Performance Computing (CHPC) scientists headed for Madagascar in February to run a week-long hands-on introductory computer programming with Linux and Python course. The course forms part of the Development in Africa with Radio Astronomy (DARA) project and was hosted at the Institute and Observatory Geophysics of Antananarivo. 
The ability to programme with Linux and Python is critical for the processing of radio astronomy data that will be emanating from the Square Kilometre Array project and as such in 2017, DARA included it in its basic training programme that aims to develop high tech skills in radio astronomy for the development, maintenance and running of radio telescopes and instrumentation. DARA is funded by the Newton Fund which promotes science and innovation partnerships that are geared towards economic development and welfare of collaborating countries. The project is targeted at countries that form part of the African Very Long Baseline Interferometry (VLBI) Network (AVN): Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia, Zambia and South Africa and have all received computer clusters from DARA and AVN, all of which have on them the same Linux setup and astronomy software installed by HartRAO (Hartebeeshoek Radio Astronomy Observatory). 
CHPC delivered the programming course twice in 2017: at the Universidade Eduardo Mondlane in Maputo, Mozambique and at the Technical University of Kenya in Nairobi. Running the course in Madagascar were CHPC scientists Drs: Daniel Moeketsi, John Poole and Krishna Govender.
CHPC is one of DARA’s South African partners with others being: HartRAO, SKA-SA, South African Space Agency and the universities of Rhodes, UNISA, Cape Town, Western Cape and North West. DARA also has a number of United Kingdom partners from the universities of Leeds, Manchester, Hertfordshire, Oxford, Bristol and Central Lancashire, as well as an industrial partner Goonhilly. Other partners include institutions at the AVN countries. Together, the DARA stakeholders seek to provide a pool of talented young people who have been inspired by astronomy to play a leading role in the emergence of new economies in their countries, Sambatriniaina Rajohnson, a Masters student in Astrophysics and Astronomy at University of Antananarivo said: “The course was helpful for us. Even though some of us had some background of scientific programming, we discussed new, interesting and important topics that will be useful as future researches.”
CHPC regularly holds similar training programmes for its users and potential users to enable then to optimise their use of high performance computing facilities.

Last Updated on Monday, 19 March 2018 11:40

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