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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 hones focus to nurture world-class research - Business Day
2006-02-10

 

Sue Blaine
THE University of the Free State plans to concentrate academic study in five areas to strengthen its status as a research institution, the university said yesterday.

The Bloemfontein-based university will focus on areas it classes as development (economics, health, literacy and other human activities) and social transformation — an analysis of how South African society is changing from a philosophical and political viewpoint.

The other three research areas are new technologies, water resources and security, and food production and security.

“It makes sense to concentrate the university’s human resources, infrastructure, financial resources and intellectual expertise,” said university rector and vice-chancellor Prof Frederick Fourie.

The move introduces a style of research that matches international trends.

Universities in Canada, Britain and Australia are setting up their research departments in this way.

In SA, the universities of Stellenbosch, the Witwatersrand, Cape Town and KwaZulu-Natal have embarked on similar strategies.

Fourie gave the example of his alma mater, the US’s Harvard University, whose Nanoscale Science and Engineering Centre is an example of “clustering” on a larger scale.

The centre is a collaboration with Harvard, the Massachusetts Institute of Technology, the University of California, Santa Barbara, the Museum of Science, Boston, and universities in the Netherlands, Switzerland and Japan.

Fourie said the modern research world was so diverse and complex that no university could cover all bases so it was better to establish areas of expertise that made it different from its peer institutions.

Having scientists and researchers work in teams meant certain issues could be researched and developed in a multidisciplinary manner. “I think it’s the only way in which any university can excel. This will help SA become world class in selected areas,” Fourie said.

It is in chemistry that the cluster model has already had its most visible results, with a slice of the university’s on-campus pharmacological testing company Farmovs, established in the 1980s, sold to the US’s Parexel International.

The company is one of the largest biopharmaceutical outsourcing organisations in the world, providing knowledge-based contract research, medical marketing and consulting services to the global pharmaceutical, biotechnology and medical device industries, according to Biospace, an internet-based company providing resources and information to the life science industry.

President Thabo Mbeki, in his state of the nation address last Friday, committed government to allocating more resources to research, development and innovation, and increasing the pool of young researchers in SA.

He said government would “continue to engage the leadership of our tertiary institutions focused on working with them to meet the nation’s expectations with regard to teaching and research”.

The university used to be home to several A-rated scientists, who are considered by a peer review, conducted by the National Research Foundation, to be world leaders in their fields, but had lost them to other institutions. Fourie hopes to lure them back, and with them postgraduate students and funding for their work.

“At universities where you get a star researcher they tend to attract people and funding; if they leave they take that with them,” he said.

Fourie said R50m would be spent on the project, with some already spent last year and the last disbursements to be made next year.

There is R10m in seed money to gather experts and improve equipment and infrastructure, and R17m has been invested in chemistry equipment and staff.

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