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18 April 2022 | Story Leonie Bolleurs | Photo Stephen Collett
Prof Ted Kroon
Prof Ted Kroon from the Department of Physics recently delivered his inaugural lecture on the topic What’s the use of a rainbow on the UFS Bloemfontein Campus.

“A rainbow is a natural phenomenon, the result of the refraction and reflection of the sun’s rays in drops of rain. As far as mankind is concerned, it’s a perfectly useless object and won’t make anyone money. Yet the poet who said, My heart leaps up when I behold a rainbow in the sky, only put into word the feeling of wonder and excitement we all have when we see a rainbow.”

“Every day I see a rainbow in my work; I do not need to wait to see one in the sky,” says Prof Ted Kroon, Professor in the Department of Physics at the University of the Free State (UFS), who used this phenomenon to introduce the topic of his inaugural lecture: What’s the use of a rainbow. 

“Far from being only a colourful spectacle with no practical value, rainbows are useful – and lead to useful things,” he believes. 

According to Prof Kroon, one can find examples of real rainbows and rainbow analogies used not only in everyday life, but also in physics. “Besides it being familiar devices in literature, culture, and even marketing, studies of rainbows can yield practical engineering information and may even help us to find new habitable planets,” he says.

Inspired by the many uses of a rainbow

In his lecture, he discussed the basic features of natural rainbows and how they come about. He also explored how the rainbow gives meaning to colour, and how this relates to the temperature of objects. He looked at an array of instances where the rainbow is used; from depicting the life of a star to indicating that we are sick (a thermometer) or when we need to refill a gas cylinder.
Moreover, Prof Kroon pointed out that rainbows are used in computer chips, stress identification, and to transmit internet data through underwater cables of glass fibre. He also referred to how the rainbow was harnessed as an engineering tool to measure refractive index and characterise fine droplet sprays used in industry. 

He continues, “Remarkably, the science developed to understand the natural rainbow can be redirected and applied to the optical properties of metallic nanoparticles, allowing the development of nanotechnology. Knowing how the natural rainbow works and its limitations, better systems have been developed to produce rainbows. Such rainbows have been used to discover new elements and to determine the age of the universe.”

As a member of an international community of phosphor researchers who are privileged to work with rainbows every day, he has used them to study the light-emitting properties of materials doped with bismuth. With this project – an initiative with the African Laser Centre taking place between 2016 and 2021 – he collaborated with the University of Khartoum in Sudan and trained a number of its postgraduate students. “My role included the guidance of students and the measurement and interpretation of the light-emitting properties of the materials. Our research during this time, considering more than a dozen materials, was summarised in 34 scientific publications that contributed to a greater understanding of bismuth ions as light-emitting materials,” he explains. 

Developing new materials, efficient in emitting blue light

He has been developing luminescent materials since 2006, primarily for general lighting (fluorescent tubes and LEDs) and displays (television, computer, and cellphone screens), as well as niche applications in medical and forensic science. 

As part of his current research, he is examining the effect of plasmonic metal nanoparticles on phosphor light emission. He is also exploring materials that absorb infrared light but emit visible light. “For this, I would like to consider the long-term stability of such materials and develop new materials that are more efficient in emitting particularly blue light,” he says. 

Prof Kroon holds a C2 rating from the National Research Foundation and has published more than 150 articles and book chapters, obtaining a Scopus h-index of 26.

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Moshoeshoe - lessons from an African icon - by Prof Frederick Fourie
2004-11-03

(The full text of the article that appeared in City Press and Sunday Independent)

Our understanding of history informs our understanding of the present. No wonder the contestation over historical figures in South Africa’s past is so fierce and so divisive.
The question is: could it be any other way? I would like to think that it could; that black and white South Africans, across linguistic, cultural, religious and other divides, can develop a shared appreciation of our history – at least with certain periods and personalities as a starting point.

One such personality whose legacy I believe offers a possible platform for unifying our still divided country is King Moshoeshoe, who lived from 1786 to 1870, and is acknowledged as the founder of the Basotho.

King Moshoeshoe is the topic of a documentary that has been commissioned by the University of the Free State as part of its Centenary celebrations this year. It is part of a larger project to honour and research the legacy of Moshoeshoe. The documentary will be screened on SABC 2 at 21:00 on November 4th.

Moshoeshoe rose to prominence at a time of great upheaval and conflict in South Africa – the 19th century, a time when British colonialism was entrenching itself, when the Boer trekkers were migrating from the Cape and when numerous indigenous chiefdoms and groupings were engaged in territorial conquests. It was the time of the Difaqane, a period when society in the central parts of the later South Africa and Lesotho was fractured, destabilised and caught in a cycle of violence and aggression.

In this period Moshoeshoe displayed a unique and innovative model of leadership that resulted in reconciliation, peace and stability in the area that later became Lesotho and Free State. It made him stand out from many of his contemporaries and also caught the attention of his colonial adversaries.

Such an evaluation is not a judgment about which model of leadership is right and which is wrong, or which leader was better than another; but merely an attempt to explore what we can learn from a particular exemplar.
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Historians point to the many progressive leadership qualities displayed by Moshoeshoe which he used effectively in establishing the Basotho nation and in defending it.
First, there is his humanism and sense of justice worthy of any great statesman. Confronted by a situation in which cannibals murdered and devoured his grandfather, Moshoeshoe chose not to take revenge. Instead he opted to rehabilitate them and feed them as he believed hunger drove them to cannibalism.

Secondly, there is his skilful alliance-building with his contemporaries such as Shaka in an attempt to neutralize those rivals who were intent on attacking his followers. This is also displayed in the way he sought the protection of the British to keep the Boer forces at bay.
Thirdly, his emphasis on peaceful options is also seen in his defensive military strategy which saw him retreat to a mountain fortress to be able to protect and build a burgeoning nation in the face of the many forces threatening its survival.

Fourthly, there is his remarkable inclusivity and tolerance for diversity which saw him unite disparate groups of refugees from the violence and hunger that displaced them and then weld them into the Basotho nation. He also engaged with French missionaries, inviting them to stay with him and advise him on Western thought, technology and religion.
These are but some of the qualities which belie the notion that all 19th century African leaders were merely marauders and conquerors that gained their ascendancy through violence. Instead Moshoeshoe is a prime example of the human-centred, democratic and pluralist roots of South African, indeed African society.

The Moshoeshoe project that we have initiated (of which the documentary, called “The Renaissance King”, forms but one part) derives from our location as a university in the Free State, a province with a particular history and a particular political culture that developed as a result of this very model of leadership. This province has benefited tremendously from leaders such as Moshoeshoe and president MT Steyn, both of whom many observers credit with establishing a climate of tolerance, respect for diversity of opinion, political accommodation and peaceful methods of pursuing political objectives in the province. Their legacy is real – and Moshoeshoe’s role can not be overstated.
In addition the project derives from the University of the Free State being a site of higher learning in a broader geo-political sense. As a university in Africa we are called upon to understand and critically engage with this history, this context and this legacy.
Besides the documentary, the UFS is also planning to establish an annual Moshoeshoe memorial lecture which will focus on and interrogate models of African leadership, nation-building, reconciliation, diversity management and political tolerance.

In tackling such projects, there may be a temptation to engage in myth-making. It is a trap we must be wary of, especially as an institution of higher learning. We need to ask critical questions about some aspects of Moshoeshoe’s leadership but of current political leadership as well. Thus there is a need for rigorous academic research into aspects of the Moshoeshoe legacy in particular but also into these above-mentioned issues.
While the documentary was commissioned to coincide with the University of the Free State’s centenary and our country’s ten years of democracy, it is a project that has a much wider significance. It is an attempt to get people talking about our past and about our future, as a campus, as a province and as a country – even as a continent, given the NEPAD initiatives to promote democracy and good governance.

The project therefore has particular relevance for the continued transformation of institutions such as universities and the transformation of our society. Hopefully it will assist those who are confronted by the question how to bring about new institutional cultures or even a national political culture that is truly inclusive, tolerant, democratic, non-sexist, non-racial, multilingual and multicultural.

I believe that the Moshoeshoe model of leadership can be emulated and provide some point of convergence. A fractured society such as ours needs points of convergence, icons and heroes which we can share. Moshoeshoe is one such an African icon – in a world with too few of them.

Prof Frederick Fourie is the Rector and Vice-Chancellor of the University of the Free State

* The documentary on “Moshoeshoe: The Renaissance King” will be screened on SABC2 on 4 November 2004 at 21:00.

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