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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.

News Archive

UFS to honour past and present Cabinet ministers
2010-04-19

The University of the Free State (UFS) is going to confer honorary doctoral degrees on former Minister of Arts, Culture, Science and Technology, Dr Ben Ngubane, and the current Minister of Finance, Mr Pravin Gordhan, during the university’s autumn graduation ceremony next month.

They will receive their honorary doctorates on 18 and 19 May respectively.

“It is an honour for the UFS to confer these honorary doctorates on people like these who have made, and continue to make outstanding contributions towards the wellbeing of this beautiful country. Being associated with people of this stature signifies the direction that the UFS is taking in our quest to be a great university, one of the best in the world,” said Prof. Jonathan Jansen, the Rector and Vice-Chancellor of the UFS.

Dr Ngubane will be honoured for his immense contribution towards positioning South Africa as a major and an influential player in the development of arts, culture, science and technology internationally.

He was the first Minister of Arts, Culture, Science and Technology in the new, democratic South Africa appointed by the former President, Nelson Mandela, in 1994. He was re-appointed to lead this ministry again by former President Thabo Mbeki in 1999.

As Premier of KwaZulu-Natal from 1996 to 1999, Dr Ngubane is credited for his role in bringing about peace and reducing the political violence that ravaged the province at that time.

In 2004 he was appointed as Ambassador to Japan where he initiated, among other projects, the South Africa-Japan University Forum (SAJU).
He has been honoured for outstanding contributions to higher education and community development and holds Honorary Doctorates from the universities of Natal, Zululand, the Medical University of South Africa (Medunsa) and the Tshwane University of Technology.

He is currently the Chairperson of the SABC Board.

Minister Gordhan, on the other hand, formed an integral part of the constitutional transition of South Africa between 1991 and 1994. He chaired the Convention for a Democratic South Africa (CODESA) Management Committee – the midwife and negotiating forum for a free South Africa. He was also co-chair of the Transitional Executive Council, which was a governance structure tasked with ensuring South Africa’s transition process prior to the historic 1994 elections.

In 1994, with the dawn of a new democracy in South Africa, Mr Gordhan became a Member of Parliament and was elected as Chairperson of the Parliamentary Constitutional Committee, which oversaw the implementation of the new constitutional order. At the same time he played a leading role in drafting the present constitution of the democratic South Africa. He also led the process of formulating a new policy framework for local government transformation.

Mr Gordhan was appointed as Deputy Commissioner at the South African Revenue Service (SARS) in March 1998 after being deployed from Parliament as part of the government’s drive to transform the public service. The following year he was appointed as Commissioner for SARS with the important task, amongst others, to transform South Africa’s Customs and Revenue administration – a strategic governmental institution.

He has represented South Africa in many international undertakings, including several peacekeeping missions, as Chairperson of the Customs Workshop for the Second Global Forum on Fighting Corruption and Safe-Guarding Integrity (2001), and is often called upon to make presentations at tax seminars and customs conferences.

In 2000 he was appointed Chairperson of the Council of World Customs Organisation (WCO), based in Brussels, a position to which he was re-elected twice, thus serving from 2000 to 2006.

Media Release
Issued by: Mangaliso Radebe
Assistant Director: Media Liaison
Tel: 051 401 2828
Cell: 078 460 3320
E-mail: radebemt@ufs.ac.za  
19 April 2010
 

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