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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

During 2011: Sport
2011-12-01

Our sports stars set their gaols high and with hard work, dedication a good measure of determination they show that they will not give up until these goals are met. A place in the national team or a medal or award in hand is enough proof that our Kovsie sportsmen and women are serious about their successes on the sports field.

 Description: 2011 Sport_Cricket Tags: 2011 Sport_Cricket  Description: 2011 Sport_Karate Tags: 2011 Sport_Karate  Description: 2011 Sport_Hockey Tags: 2011 Sport_Hockey  Description: 2011 Sport_Netball Tags: 2011 Sport_Netball  Description: 2011 Sport_Rugby Tags: 2011 Sport_Rugby

Some of our stars this year were:

Athletics:

Thuso Mpuang, our Kovsie Sportsman of the year, represented South Africa during the World Athletic Championships in Deague, Korea. He obtained the silver medal in the 200m during the World Student Games in Shenzhen, China and a gold medal as a member of the 4 x 100m relay team.

Janette Siebert represented South Africa during the Southern Africa Championships in Maputo, Mozambique.

Boy Soke represented South Africa during the Africa Cross Country Championships in Cape Town. He also represented South Africa during the World Cross Country Championships in China.

Cricket:

The 21-year-old former Kovsie, Obus Pienaar, who was still playing cricket for our university club until the end of the season (end of March), has been playing abroad for the Irish cricket club Waringstown from the end of April 2011.
We are proud of Obus’ achievements, in particular his contribution to the match against the CIYMS. During this game, Obus hit the highest score ever in the Northern Cricket Unions when he scored 244 runs in only 114 balls. This included 22 sixes and 13 fours. During his innings in this match, Obus also broke the July 2004 record of his compatriot, AB de Villiers of the Proteas.

Hockey:

Lesley Ann George represented the Protea Women’s Hockey Team during the series against China, Belgium and Azerbaijan. She was also a member of the Protea Women’s Hockey Team during the Champs Challenge in Ireland. The team finished fifth.

Nicole de Vries represented the Protea Women’s Hockey Team during the series against China, Belgium and Azerbaijan. She was also a member of the Protea Women’s Hockey Team during the Africa Cup in Bulawayo. The team obtained a gold medal.

Hettie Oosthuizen represented the Protea Women’s Hockey Team during the series against China, Belgium and Azerbaijan.

Izelle Lategan represented the Protea Women’s Hockey Team during the series against China, Belgium and Azerbaijan.

Nicole Kemp was a member of the Protea Women’s Hockey Team during the Africa Cup in Bulawayo. The team obtained a gold medal.

Karate:

Elsabe le Roux was a member of the Protea JKA Shotokan Karate Team that participated in the Africa Zone 6 Championships in Maputo where she obtained a gold and silver medal.

Bruno Schwalbach was a member of the Protea JKA Shotokan Karate Team that participated in the Africa Zone 6 Championships in Maputo where he obtained two gold medals. He was also a member of the Protea JKA Shotokan Karate Team that participated in the Common Wealth Karate Championship in Australia where he obtained one silver and two bronze medals. He was a member of the Protea JKA Shotokan Karate Team that participated in the All Africa Games in Maputo Mozambique where he obtained a bronze medal.

Balungile Nchofe was a member of the Protea JKA Shotokan Karate Team that participated in the Africa Zone 6 Championship in Maputo, where he obtained a gold medal.

Netball:

Kovsies’ netball team has performed well over the past year with, amongst others, the inclusion of players in the SA Universities World-cup Group.

Karla Mostert and Maryka Holtzhausen participated during the World Cup in Singapore in the SPAR SA Protea team.

We are also proud of the eight players who have been included in the SA team. They are Zimari Smit, Sheri Duimpies, Ane Botha, Danique du Toit, Nieke Loubser, Karla Mostert, Fikile Mkhuzangwe and Lauren-lee Christians.

At the SA tournament, Ane Botha was named as the centre-court player of the tournament, whilst Karla Mostert was named as the best defending player. Karla has also been included in the SPAR SA Protea team to the All African Games, which start in Mozambique at the end of August.

Rugby:

Boom Prinsloo and Robert Ebershohn are representing the Springboks in the HSBC Sevens World Series.

Soccer:

Gabisile Hlumbane, our Kovsie Sportswomanof the year, is a member of the Banyana Banyana National Soccer Team. The team obtained a bronze medal at the African Women’s Championships during October 2010, a gold medal at the Unity Cup Hosted during December 2010, a silver medal at the COSAFA Women’s Championship hosted during July 2011 and qualified for the London Olympics in 2012.

Squash:

Paul Rodrigues represented the South African U/ 23 team at the All Africa Squash Championships in Johannesburg.

Triathlon:

Nelmaré Loubser represented the SA Elite Team during the World Championships in Spain.

 

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