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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 Law students take on the world
2007-03-25

Back, from left: Prof. Elizabeth Snyman-Van Deventer (Associate Professor at the Department of Mercantile Law, UFS), Lucien Companie, Dee Leboela, Sunette Visser and Mr Jaco Deacon (Lecturer at the Department of Mercantile Law, UFS). Front, from left: Mr Van Aswegen (Naudes Attorneys), Prof Rita-Marie Jansen (Associate Professor at the Department of Private Law, UFS), J.C. Smith and Vicky Olivier.

Photo: Stephen Collett

A team of eight students from the Faculty of Law at the University of the Free State (UFS) will compete in an international arbitration competition in Vienna, Austria, from 30 March to 5 April 2007.

The Willem C. Vis International Commercial Arbitration Moot is an annual competition organised by the Institute of International Commercial Law at the Pace University School of Law in New York, USA. The goal of the competition is to foster the study of international commercial law and to train students in methods of alternative dispute resolution.

Students will be judged on two crucial phases: the preparation of memoranda for the claimant and respondent, and the presentation of oral arguments before an arbitral tribunal. “The Moot teaches the basic framework of international arbitration and the application of the uniform sales law to all participating students during the preparation of the memoranda and the oral arguments,” says one of the team members, Dee Leboela, who also took part in last year’s competition.

“This competition definitely prepares students for the legal practice in all facets, whether as advocate, legislator or other areas,” added Deman Smit, one of the team members who also took part last year.

This competition brings together students from a range of legal systems and cultures from all over the world to learn from the process and from each other. “This encourages the development of social competence, and lifelong skills that are needed in our profession, of which social relations play an important role,” says Leboela.

In its maiden participation last year the UFS did not disappoint, with the highest score of 49 out of 50 and the lowest being 38 out of 50. This year the UFS will compete with 178 universities from 51 countries. “With the right strategy, which involves selecting the students on academic merit and excellent advocacy skills, I believe we would make it to the top 32,” says Leboela with confidence.

The UFS team is Leboela, Smit, Lucien Companie, Vicky Olivier, Sunette Visser, Qaqamba Vellem, Hanno Bekker and Lucy Nthotso.
 

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