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27 July 2021 | Story Leonie Bolleurs | Photo UFS Photo Archive
Prof Hendrik Swart played a key role in the Department of Physics acquiring the PHI Quantes XPS system, the first in Africa and one of only 20 in the world.

The state-of-the-art equipment in the Department of Physics at the University of the Free State (UFS) differentiates this department from its competitors. Availability of the equipment makes it possible for researchers as well as students to deliver work that receives national and international recognition. 

Recently, the department acquired a PHI Quantes XPS system, the first in Africa and one of only 20 in the world. 

Creating better phosphor 

“The Quantes XPS system uses X-rays to determine the chemical composition of molecules on the surface of a sample. The system is unique in the sense that it also has an extra X-ray source that can determine the chemical state below the surface, which was not possible in the past.  This will help us to dictate the position of defects in our phosphor materials that will consequently enable us to create better phosphor for solid state lighting as well as solar cell applications,” explains Prof Hendrik Swart, Senior Professor in the Department of Physics, who also holds the SARChI Chair in Solid State Luminescent and Advanced Materials.

After he had the opportunity to observe the system in the factory in Chigasaki, Kanagawa, Japan, where he attended a conference, Prof Swart was very impressed by its performance. He discussed it with Prof Koos Terblans, Head of the department, and other colleagues, and started making plans to buy the system. 

When the department first bought the X-ray photoelectron spectroscopy (XPS) system in 2007/2008, it became the national facility on XPS measurements. Not only is this an upgrade of the XPS system bought 14 years ago, but the new system will enable the department to do more measurements. “The number of samples that we have to handle has just become too much for one system. The new system’s increased capacity for making measurements addresses this challenge and it also gives UFS scientists and postgraduate students more time to spend on fundamental measurements to develop research of a higher level,” says Prof Swart.

(The Quantes XPS system. Photo:Supplied)

Explaining about the measurements, Prof Swart says: “This advanced X-ray photoelectron spectroscopy (XPS) instrument has the capability to analyse the very small area that the user is interested in and a large area of the uniform sample surface. The two different types of X-ray sources – the hard X-ray source and the more conventional soft X-ray source – can be switched automatically, allowing users to analyse the same area and/or points of a sample. The PHI Quantes XPS system ensures the availability of superior features such as automatic analysis, automatic sample transfer, turnkey charge neutralisation, and advanced data processing.”

“This XPS instrument is designed to pioneer new methods and applications transcending conventional ideas of what is possible.”

Optimising efficiency of materials

Prof Swart says the Department of Physics, especially the Research Chair in Advanced and Luminescent Materials, is developing new high-technology materials on a daily basis. “It is very important to know the chemical composition and defect distribution of the materials in order to add value to the fabrication of these materials,” he adds.

“The distribution of these defects is vital for the efficiency of the phosphor materials. If we know where these defects are located, we can determine the mechanisms of the light output coming from these phosphors,” describes Prof Swart.

Research conducted as part of the Research Chair in Solid State Luminescent and Advanced Materials will benefit significantly from this new system.

(Prof Koos Terblans, Head of the Department of Physics next to the Quantes XPS system. Photo:Supplied) 

“We are currently concentrating on phosphors as sensors (temperature), light-emitting diodes (LEDs), and solar cells, where we optimise the efficiency and durability of these materials. Any new knowledge, which I believe the PHI Quantes XPS system will provide us, will help us to reach our goal much quicker,” he says. 

Apart from the positive impact on research, the PHI Quantes XPS system will also be a benefit to society in the long term. Improved LEDs can be used to save electricity, and better solar cells can help to generate electricity, to mention but two examples. 

News Archive

Inaugural lecture: Prof. Phillipe Burger
2007-11-26

 

Attending the lecture were, from the left: Prof. Tienie Crous (Dean of the Faculty of Economic and Management Sciences at the UFS), Prof. Phillipe Burger (Departmental Chairperson of the Department of Economics at the UFS), and Prof. Frederick Fourie (Rector and Vice-Chancellor of the UFS).
Photo: Stephen Collet

 
A summary of an inaugural lecture presented by Prof. Phillipe Burger on the topic: “The ups and downs of the South African Economy: Rough seas or smooth sailing?”

South African business cycle shows reduction in volatility

Better monetary policy and improvements in the financial sector that place less liquidity constraints on individuals is one of the main reasons for the reduction in the volatility of the South African economy. The improvement in access to the financial sector also enables individuals to manage their debt better.

These are some of the findings in an analysis on the volatility of the South African business cycle done by Prof. Philippe Burger, Departmental Chairperson of the University of the Free State’s (UFS) Department of Economics.

Prof. Burger delivered his inaugural lecture last night (22 November 2007) on the Main Campus in Bloemfontein on the topic “The ups and downs of the South African Economy: Rough seas or smooth sailing?”

In his lecture, Prof. Burger emphasised a few key aspects of the South African business cycle and indicated how it changed during the periods 1960-1976, 1976-1994 en 1994-2006.

With the Gross Domestic Product (GDP) as an indicator of the business cycle, the analysis identified the variables that showed the highest correlation with the GDP. During the periods 1976-1994 and 1994-2006, these included durable consumption, manufacturing investment, private sector investment, as well as investment in machinery and non-residential buildings. Other variables that also show a high correlation with the GDP are imports, non-durable consumption, investment in the financial services sector, investment by general government, as well as investment in residential buildings.

Prof. Burger’s analysis also shows that changes in durable consumption, investment in the manufacturing sector, investment in the private sector, as well as investment in non-residential buildings preceded changes in the GDP. If changes in a variable such as durable consumption precede changes in the GDP, it is an indication that durable consumption is one of the drivers of the business cycle. The up or down swing of durable consumption may, in other words, just as well contribute to an up or down swing in the business cycle.

A surprising finding of the analysis is the particularly strong role durable consumption has played in the business cycle since 1994. This finding is especially surprising due to the fact that durable consumption only constitutes about 12% of the total household consumption.

A further surprising finding is the particularly small role exports have been playing since 1960 as a driver of the business cycle. In South Africa it is still generally accepted that exports are one of the most important drivers of the business cycle. It is generally accepted that, should the business cycles of South Africa’s most important trade partners show an upward phase; these partners will purchase more from South Africa. This increase in exports will contribute to the South African economy moving upward. Prof. Burger’s analyses shows, however, that exports have generally never fulfil this role.

Over and above the identification of the drivers of the South African business cycle, Prof. Burger’s analysis also investigated the volatility of the business cycle.

When the periods 1976-1994 and 1994-2006 are compared, the analysis shows that the volatility of the business cycle has reduced since 1994 with more than half. The reduction in volatility can be traced to the reduction in the volatility of household consumption (especially durables and services), as well as a reduction in the volatility of investment in machinery, non-residential buildings and transport equipment. The last three coincide with the general reduction in the volatility of investment in the manufacturing sector. Investment in sectors such as electricity and transport (not to be confused with investment in transport equipment by various sectors) which are strongly dominated by the government, did not contribute to the decrease in volatility.

In his analysis, Prof. Burger supplies reasons for the reduction in volatility. One of the explanations is the reduction in the shocks affecting the economy – especially in the South African context. Another explanation is the application of an improved monetary policy by the South African Reserve Bank since the mid 1990’s. A third explanation is the better access to liquidity and credit since the mid 1990’s, which enables the better management of household finance and the absorption of financial shocks.

A further reason which contributed to the reduction in volatility in countries such as the United States of America’s business cycle is better inventory management. While the volatility of inventory in South Africa has also reduced there is, according to Prof. Burger, little proof that better inventory management contributed to the reduction in volatility of the GDP.

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