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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

Council votes on appointment of senior staff
2004-11-18

The Council of the University of the Free State (UFS) today voted on the filling of three senior vacancies, including one post at Dean level and two at the level of Vice-Dean.

The Council voted as follows:

Dr Natie Luyt will be offered the post of Dean: Student Affairs Prof Engela Pretorius will be offered the post of Vice-Dean: Faculty of Humanities Dr Choice Makhetha will be offered the post of Vice-Dean: Student Affairs

“There are special challenges for the UFS in the short and medium term regarding transformation of our residences, and a certain combination of management qualities and skills is desirable. As a result of the diversity of the UFS’s student community it is therefore important to us to follow a team approach to deal with the challenges. With the combination of Drs Luyt and Makhetha, I believe we will be able to manage student affairs effectively and skillfully,” says Prof Frederick Fourie, Rector and Vice-Chancellor of the UFS.

“It is wonderful that we are able to celebrate the outcome of this process that has brought forward such excellent candidates who reflect our country’s diversity. It shows that we can achieve the goals of quality and diversity at the same time,” says Prof Fourie.

Prof Pretorius obtained all her qualifications (BA, BA (Hons) (cum laude), MA (cum laude) and D Phil) from the UFS, except for the Certificate in Gender Policy Management (cum laude) which she obtained in 2000 from WITS. She joined the Department of Sociology at UFS in 1980 and has headed the Department since 2001. She acted as Vice-Dean: Faculty of Humanities since July 2004. She has some thirty publications to her credit, published both nationally and internationally and has delivered 20 national and international papers. She is a member of the South African Sociological Association and is a member of the Council of the association and of the Editorial Board of Society in Transition, the society’s journal. She is also a member of the South African Academy for Science and Art and the Federation of African Women Educationalists in South Africa (FAWESA). Project involvement includes the Australian Women’s Executive Development Programme and the project Executive Development of Senior Women in South African Higher Education Institutions. She is also an NRF panelist.

Dr Luyt obtained his qualifications (BA, BA (Hons) (cum laude), MA (cum laude) and D Phil) at the UFS and started his career at the same institution in 1980 as lecturer in Political Science. He was promoted to senior lecturer in 1983 and appointed as Director: Student Affairs in 1997. He has been acting as Dean: Student Affairs since 2003. Dr Luyt completed several work-related training courses, among others a course in ethnic and multiculturality at the Swiss Institute for Federalism and a course in conflict management at the South Tyrolean Economic and Social Institute.

Dr Makheta also obtained all her qualifications (BA, BA (Hons), MA in Political Science and Ph D in Political Science) at the UFS and started working as a student assistant in Political Science at the same institution in 1999. She was promoted to junior assistant in 2000, coordinator and facilitator of Political Science in 2001, assistant/acting Director: Student Affairs in 2001 and acting Director: Student Affairs in 2003. Dr Makhetha is currently a Senior Political Analyst at the Department of Foreign Affairs.

The UFS Council also approved the promotion of nine professors to the rank of senior professor. They are Proff Louise Cilliers (Department English and Classical Languages), Dap Louw (Department of Psychology), Philip Nel (Department Afro-Asiatic Studies, Sign Language and Language Practice), Dirk van den Berg (Department of History of Art and Visual Culture Studies) Dingie van Rensburg (Director: Centre for Health Systems Research and Develoment), Andries Raath (Department of Constitutional Law and Philosophy of Law), James du Preez (Department of Microbial, Biochemical and Food Biotechnology), Johan Grobbelaar (Department of Plant Sciences) and Louis Scott (Department of Plant Sciences).

This is the first group ever of senior professors at the UFS. The post level was created to provide better career and earnings opportunities for high quality academics and to increase the attractiveness of an academic career to young people.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
 

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