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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

Legal elite tackle thorny issue of corruption
2013-01-24

 

Our Faculty of Law brought together top experts and judges for a Symposium on Corruption, to investigate one of the most pressing concerns of South Africans.
Photo: Stephen Collett
24 January 2013



   YouTube Video

Chief Justice Mogoeng Mogoeng yesterday (24 January 2013) concluded the proceedings of the first day of the International Symposium on Corruption, hosted by the Faculty of Law of the University of the Free State (UFS). In his address Justice Mogoeng made no excuses as to the magnitude of the threat corruption presents to South African citizens.

“Urgent action and efficient measures are called for to arrest this scourge, for the sake of our constitutional democracy,” he warned. “Our vibrant constitutional democracy will not and cannot survive in the face of rampant corruption.”

Justice Mogoeng said the spate of civil and labour unrest erupting throughout the country can be attributed to corruption. According to him the scope and far-reaching implications of corruption drives South Africans to “boiling point” and evokes “anger, frustration and a don’t-care-attitude that often manifests in widespread protest actions” and disrespect for the rule of law.

“South Africans, irrespective of race or creed, must identify and focus on their common enemies and find a conciliatory and unifying way of dealing with what divides them, including the lingering prejudices of the past,” Justice Mogoeng urged.

Despite the threat corruption poses, he stressed that all South Africans have a role to play in the fight against corruption and that there are different role players that can become involved in the process. Especially important is the media and faith-based agencies which, according to Justice Mogoeng, can regenerate morals and secure a “national moral code.” The State must further ensure enforcement of anti-corruption measures and preside over the selection of individuals of “solid character” to reside in agencies meant to fight corruption.

He highlighted the need for an unbiased and independent judiciary, one immune to outside influences controlled by powerful forces, as well as personal agendas.

Although Justice Mogoeng believes that the private sector is most guilty of transgressions based on corruption, he stated that a “well-coordinated war” against it must be waged in all sectors in order to stamp it out.

Justice Mogoeng presided over the unveiling of the redesigned foyer of the CR Swart Building and praised the Faculty of Law for its innovation with regard to the symposium.

“I look forward with great optimism to more well-organised symposiums that strike at the nerve-centre of the well-being of our constitutional democracy,” he concluded.

Symposium seeks answers and solutions

The Faculty of Law at the University of the Free State (UFS) concluded its International Symposium on Corruption on Friday 25 January 2013. The event featured a stellar cast of speakers, including the Chief Justice of South Africa, three current Supreme Court of Appeal judges, high-court judges, advocates, prosecutors, journalists, as well as local and international legal academics.

Throughout the two-day symposium, corruption was dissected as a severe problem in the South African socio-economic landscape and solutions were sought to alleviate the pressing concern.

The main attractions of the symposium were undoubtedly the attendance and presentations delivered by Chief Justice Mogoeng Mogoeng, as well as Prof. Leon Wessels. Prof. Wessels was described as “one of the founding fathers of the constitution of South Africa” by Judge Fritz Brand, a current Appeal Court judge and the third-longest serving judge in the country.

“Corruption is stealing the constitutional dream of this country. Corrupt leaders are fearless, those who expose corruption, are fearful,” Prof. Wessels warned.

Judge Brand closely trails the second longest serving judge in the country in former Kovsie, as well as former UFS Council Chairman, Judge Faan Hancke. Both judges addressed the symposium and chaired sessions, along with Prof. Johan Henning, Dean of the Faculty of Law, and Judge Ian van der Merwe, Chairman of the UFS Council.

It was, however, not all doom and gloom, as several of the speakers offered tangible ideas in what was often termed the “war on corruption”. Celebrated Sunday Times journalist Mzilikazi wa Afrika who has been arrested following the police leasing scandal which he exposed, urged South Africans to stand together in their fight against corruption, before it is too late.

People on the front lines in the day to day fight against corruption also spoke at the symposium, giving the audience a better understanding of the intricacies and challenges involved in the process. The Head of the National Prosecuting Authority’s Asset Forfeiture Unit, Mr Willie Hofmeyer, as well as Advocate Xolisile Khanyile, who is the Director of Public Prosecutions in the Free State, elucidated this struggle.

The symposium also hosted Prof. Chizu Makajima, a celebrated academic from the United Kingdom.

The two-day symposium ended in style as the delegates gathered in the Centenary Hall on the Bloemfontein Campus for lunch, with a further address by Prof. Leon Wessels


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