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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

The launch of a unique conservation project
2011-06-06

 

Our Department of Animal, Wildlife and Grassland Sciences launched a very special pilot project at Woodland Hills Wildlife Estate in Bloemfontein on Friday 03 June 2011, which aims to eventually aid in the conservation and study of one of Africa’s most graceful animals.

The project aims to provide the scientific basis needed for making future decisions in the best interests of the giraffe in the Kgalagadi Transfrontier Park in the Northern Cape and involves collaring and monitoring the behaviour and movement of these animals via GPS.

Based on the public interest in the giraffe and the increased impact of the growing giraffe population on the vegetation in the area, SANParks has been considering the translocation of a number of Kgalagadi giraffe. Due to limited information regarding their adaptation success and potential impact on their new environment, thorough planning and subsequent monitoring of the species is required.

Mr Francois Deacon from our university decided to undertake a PhD study to address the existing challenges. This will be the first study of its kind, undertaken on giraffe.

He says he decided on this project because of his love for animals and conservation. “There are nine sub-species of giraffe and seven of these are already endangered. I want to involve people and make them aware of the plight of the animals and the need for conservation,” he said.

The project kicked off on Friday morning, with a group of students and curious nature-lovers tracking a herd of giraffe at Woodland Hills. The challenge laid in identifying one of the animals which could easily be collared with a GPS device, tranquilising it, and applying the device, without harming the animal.

After a young bull was identified, it was up to Dr Floris Coetzee, a veterinarian, to get close enough to the animal to tranquilise it, and to the group of students to catch it and hold it down. All this was done perfectly and the animal was fitted with its new collars. The collars were designed and made by Mr Martin Haupt, who gained extensive experience in the design of similar collars for other research studies.

Mr Deacon will spend the following two weeks personally monitoring the animal constantly, to ensure that the collars do not cause any discomfort or injury and to determine whether it should be removed or adapted.

It has taken Mr Deacon over a year to plan the collaring process and the associated study. He says the main challenges in the project are financial, since it will cost approximately R500 000 to run over five years.

Thus far he has been supported by Mr Pieter Malan of Woodland Hills, Mr Cas Kempff of Cas Kempff Consulting Engineers and Prof. Frans Swanepoel of the UFS’ Directorate of Research Development, all of whom have been benefactors of the project.
Information gathered from the pilot project will provide the data to assess how to best fit the collar onto the giraffe to ensure that the animal is comfortable and that the collar will last in the wild.  Scientific data will be generated and processed for use by the Woodland Hills Wildlife Estate management.

Should the pilot project be successful, between four and eight giraffe in the Kgalagadi will be tracked using the satellite GPS collars. The GPS collars will enable the constant recording of the location of individual giraffe for up to 2 years. This will allow control and monitoring of the animals in real-time.

The main benefits of the project include, amongst others, improved decision-making, informing tourism development, education and community involvement, improved sustainability and improved cross-border collaboration between South Africa and Botswana.

Anyone who wishes to get involved with the project or get more information, should contact Me. Sonja Buhrmann at sbuhrmann@vodamail.co.za or 0827735768.
 

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