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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

Situation on the Bloemfontein Campus, and letter to parents
2016-02-28

Letter to parents from Prof Jonathan Jansen, Vice-Chancellor and Rector of the UFS 

 

Statement by Prof Jonathan Jansen, Vice-Chancellor and Rector of the University of the Free State (UFS) about the situation on the Bloemfontein Campus


1.    As all of you know, last night we witnessed a really tragic event at Xerox Shimla Park on the Bloemfontein Campus on the occasion of the Varsity Cup rugby match between NMMU (FNB Madibaz) and UFS (FNB Shimlas).
2.    The game started at 18:30 and about 17 minutes into the match, a group of protestors sitting on the north-eastern side of the stadium decided to invade the pitch and disrupt the game in progress.
3.    After a short while, some of the spectators also invaded the field, chasing and brutally beating those protestors whom they caught.
4.    As a university leadership we condemn in the strongest terms possible the vicious attack on the protestors. Nobody, repeat nobody, has the right to take the law into their own hands. While the protests were illegal and disruptive, it did not harm to the physical well-being of the spectators.
5.    The reaction from the group of spectators, however, not only opened old wounds, it trampled, literally and figuratively, on the dignity and humanity of other human beings. This we condemn in no uncertain terms, and no stone will be left unturned to find those who acted so violently on what should have been a beautiful occasion that also brought families and young children together to enjoy an evening of sport.
6.    I cannot over-emphasise our level of disgust and dismay at the behaviour of the spectators. It is NOT what the University of the Free State (UFS) is about and we are working around the clock to gather evidence on the basis of which we will pursue both charges and, in the case of students, also disciplinary action on campus.
7.    At the same time, the invasion of the pitch is also completely unacceptable and we will seek evidence on the basis of which we will act against those who decided to disrupt an official university event.
8.    Clashes between students occurred afterwards on campus and members of the Public Order Policing had to disperse some of them. The situation was stabilised in the early hours of the morning.
9.    Disruption continued this morning (23 February 2016) when students damaged some university buildings, a statue, and broke windows. Additional reinforcements from the South African Police Service were brought in to stabilise the campus. Additional security has also been deployed.


Broader picture
10.    We are very aware of the national crisis on university campuses and the instability currently underway. While the UFS has been largely peaceful, we have not been spared this turmoil, as last night’s events showed.
11.    We are also conscious of the fact that even as we speak, various political formations are vying for position inside the turmoil in this important election year. In fact, part of the difficulty of resolving competing demands is that they come from different political quarters, and change all the time.
12.    We are therefore learning from reliable sources that the Varsity Cup competition is, in fact, a target of national protests in front of a television audience.
13.    And we are aware of the fact that these protests are not only led by students but also by people from outside who have no association with the university. Just as the violent spectators involved on Monday night also included people from outside the university.

The demands

14.    My team has worked around the clock to try to meet the demands of contract workers demanding to be in-sourced. In fact, this weekend past, senior colleagues sat with worker leaders in the township to try to find ways of meeting their demands. We were hoping that such an agreement would be finalised by Monday afternoon (22 February 2016), but on the same Monday morning workers and students were arrested after moving onto Nelson Mandela Avenue, after which the South African Police Service (SAPS) took over as the matter became a public safety concern outside the hands of the university. Since then, it was difficult to return the workers to settle on a possible agreement.
15.    The fact is that the UFS has been in constant negotiation with contract workers to provide our colleagues with a decent wage and certain benefits. In fact, towards the end of last year we raised the minimum wage from R2 500 to R5 000. We were in fact hoping that the continued negotiations would improve that level of compensation even as we looked at a possible plan for insourcing in the future. We made it clear that if we could insource immediately, we would, but that the financial risk to the university was so great that it threatened the jobs of all our staff. Those negotiations were going well, until recently, when without notice the workers broke away and decided to protest on and around campus.
16.    While these negotiations were going on, the Student Representative Council (SRC) on Monday 22 February 2016 also decided to protest. While the vast majority of our 32 000 students were in classes and determined to get an education, a very small group led by the SRC President decided to protest; some invaded the UFS Sasol Library and the computer centre, and with the President eventually made their way to Xerox Shimla Park on which route they confronted the police, interrupted traffic and in fact injured some of our security staff as well as police officials.
17.    The university is definitely proceeding to collect evidence on these illegal and violent acts and will also act firmly against students involved in these protests.

Summary
18.    The events of Monday night represent a major setback for the transformation process at the UFS. While we have made major progress in recent years—from residence integration to a more inclusive language policy to a core curriculum to very successful ‘leadership for change’ interventions for student leaders—we still have a long way to go.
19.    One violent incident on a rugby field and we again see the long road ahead yet to be travelled. As I have often said before, you cannot deeply transform a century-old university and its community overnight. We acknowledge the progress but also the still long and difficult path ahead. We will not give up.
20.    We have 32 000 students on our campuses; the overwhelming majority of them are decent and committed to building bridges over old divides as we have seen over and over again. So many of our students, black and white, have become close and even intimate friends working hard to make this a better campus and ours a better community and country. Like all of us, they are gutted by what they saw on Monday, but the hundreds of messages I received from parents, students, and alumni this past 20 hours or so said one thing—keep on keeping on. And we will.

 

The Big Read: An assault on transformation (Times Live kolom deur Prof Jonathan Jansen: 25 Februarie 2016)

 

 

 


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