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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

Department at the UFS receives special visitors
2008-02-26

 

From the left are: Prof. Hans Ausloos, Prof. Bénédicte Lemmelijn, and Prof. Fanie Snyman (Head of the Department of Old Testament at the UFS). Both Prof. Ausloos and Prof. Lemmelijn are professors in the Old Testament within the Bible Science Investigation Unit of the Katholieke Universiteit Leuven in Belgium.
Photo: Lacea Loader
 

Department at the UFS receives special visitors

The Department of Old Testament in the Faculty of Theology at the University of the Free State (UFS) has for the first time received a visit from two guest professors from the Katholieke Universiteit Leuven (KU) in Belgium who are presenting undergraduate lectures.

What makes the visit even further unique is that the guest professors are a married couple who specialise in the Old Testament.

“Proff. Hans Ausloos and Bénédicte Lemmelijn are visiting the faculty for about a month to present undergraduate programmes. They are part of a co-operative agreement between the UFS and the KU Leuven. This is also a good way of giving our students exposure to European experts,” says Prof. Snyman, Head of the Department of Old Testament at the UFS.

The couple and their three children, Matthias (10), Elke (8) and Ruben (6), are staying in Prof. Daan Pienaar’s house for the duration of their stay. Prof. Pienaar is a retired professor in Biblical Science at the UFS. The children are at school in Universitas Primary School for the duration of the family’s stay in Bloemfontein. “The headmaster was very kind and provided them with school uniforms out of the school’s second hand clothing shop, of which they will not part easily as they do not wear school uniform in Belgium,” says Prof. Lemmelijn.

Proff. Lemmelijn and Ausloos cannot stop talking about the charm of the university’s Main Campus. “In Leuven the university is part of the city and the university buildings are situated amongst the city buildings. We do our shopping while the students move from one class to the other! Here, the university is a town on its own and the students are given the opportunity to socialise in a protected environment,” says Prof. Lemmelijn.

The couple is also just as impressed with Bloemfontein. “The safety issue in South Africa is accentuated in such a way in Europe that we are astounded by the peaceful and friendly atmosphere of the city. We are also surprised with the shopping centres that are under one roof. In Belgium the shops are situated far apart,” says Prof. Lemmelijn.

The couple finds the living costs – especially food – to be quite expensive. “Some basic food is even more expensive than it is in Belgium,” says Prof. Ausloos.

Over and above their commitment to lecture, the couple is also busy with research on the Greek translation of the 12 Small Prophets in co-operation with Prof. Snyman.

“This is the first time that lecturers from the KU Leuven visit the Department of Old Testament for such a long time and are part of the normal curriculum. It is interesting to note that the teaching modules between the two departments resemble each other in such a way that lectures which are presented in Leuven are also repeated here,” says Prof. Snyman.

Both Proff. Ausloos and Lemmelijn are professors in the Old Testament within the Bible Science Investigation Unit of the KU Leuven. They publish articles internationally on the editorial and text criticism of the Old Testament and are involved with international investigative programmes such as the Hexapla Project and Septuaginta-Deutsch. Prof. Ausloos is director of the Leuvense Centre for Septuagint Studies and Textual Criticism and Prof. Lemmelijn is an associate in the centre. Together they have published several financed investigative projects on the characterising of the translation technique of the Greek Bible translation.

Media Release
Issued by: Lacea Loader
Assistant Director: Media Liaison
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: loaderl.stg@ufs.ac.za  
25 February 2008
 

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