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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

Statement: Visit of the Portfolio Committee on Education to the UFS
2005-02-25

The chair of the Portfolio Committee on Education (PCE) Prof Shepherd Mayatula has commended the management of the University of the Free State (UFS) for its positive approach to the incorporation of the Vista and Qwaqwa campuses.

According to a statement issued by the university’s communication section, Prof Mayatula said that while there were outstanding issues to address, a platform had been created through the visit of the portfolio committee for the UFS to find solutions.

Speaking at the end of a visit to the Bloemfontein campus of the UFS, Prof Mayatula said: “You know the issues that exist between the three campuses and you know the solutions. You don’t need recommendations from the Committee.”

Earlier today the PCE held a three-way meeting between the PCE, the management of the UFS and the Vista Task Team, representing staff and students at the Bloemfontein campus of the former Vista University .
 

The Bloemfontein campus of the former Vista University was incorporated into the UFS in January 2004.

The multi-party delegation from the PCE was led by its chairperson, Prof S Mayatula, while the delegation from the UFS was led by the Rector and Vice-Chancellor, Prof Frederick Fourie, while the Vista Task Team was lead by Mr Paseka Mokoena.

Following a presentation by the Vista Task Team and a presentation by the UFS management, other committee members also commended the UFS for the spirit in which outstanding issues were being handled.

It was indicated by portfolio committee members that other universities have far more serious problems than the UFS, and that some of these universities have also been visited by the PCE. The UFS appears to be on the road to be an important pilot case for incorporations and mergers.

The issues that were discussed during today’s meeting included the following:

  • outstanding issues in the process of incorporating the Bloemfontein campus of the former Vista University into the UFS, including:
  • staff issues and conditions of service
  • issues of student aid and pipeline students
  • governance of the UFS
  • the long term utilisation of Vista as a site

The Rector and Vice-chancellor of the UFS, Prof Fourie, expressed his appreciation for the role played by the Portfolio Committee on Education in bringing about a common understanding of the transformation issues facing the UFS.

Prof Fourie said the Portfolio Committee’s visit was a useful intervention to bring about a sense of urgency in resolving matters affecting the Vista campus as well as the Qwaqwa campus.

Issued by: Mr Anton Fisher
Director: Strategic Communication
Cell: 072-207-8334
Tel: 051-401-2749
25 February 2005

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