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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 researcher selected as emerging voice
2016-11-03

Description: Andre Janse van Rensburg  Tags: Andre Janse van Rensburg

André Janse van Rensburg, researcher at the
Centre for Health Systems Research and Development
at the University of the Free State, will be spending
almost three weeks in Vancouver, Canada. He will be
attending the Emerging Voices for Global Health programme
and Global Symposium on Health Systems Research.
Photo: Jóhann Thormählen

His research on the implementation of the Integrated School Health Programme (ISHP) in rural South Africa led to André Janse van Rensburg being selected to become part of the Emerging Voices for Global Health (EV4GH) group.

It is a collection of young, promising health policy and systems researchers, decision-makers and other health system professionals. A total of 222 applications from 50 countries were received for this programme, from 3-19 November 2016 in Vancouver, Canada.

The EV4GH is linked to the fourth Global Symposium on Health Systems Research (HSR2016), from 14-18 November 2016. It also taking place in Vancouver and Janse van Rensburg will be taking part, thanks to his research on the ISHP in the Maluti-a-Phofung area. He is a researcher at the Centre for Health Systems Research & Development (CHSR&D) at the University of the Free State (UFS).

The theme of the HSR2016 is Resilient and Responsive Health Systems for a Changing World. It is organised every two years by Health Systems Global to bring together roleplayers involved in health systems and policy research and practice.

Janse van Rensburg also part of Health Systems Global network
The EV4GH goals relate to the strengthening of global health systems and policies, particularly from the Global South (low-to-middle income countries with chronic health system challenges). The initiative involves workshops, presentations, and interactive discussions related to global health problems and solutions.

As an EV4GH alumni, Janse van Rensburg will become part of the Health Systems Global network. Partnering institutions include public health institutes from China, India, South Africa, Belgium, and the UK.

“The EV4GH is for young, promising health
policy and systems researchers, decision-makers
and other health system professionals.”

Research aims to explore implementation of schools health programme
In 2012, the ISHP was introduced in South Africa. This policy forms part of the government's Primary Health Care Re-engineering Programme and is designed to offer a comprehensive and integrated package of health services to all pupils across all educational phases.

Janse van Rensburg, along with Dr Asta Rau, Director of the CHSR&D, aimed to explore and describe implementation of the ISHP. The goals were to assess the capacity and resources available for implementation, identify barriers that hamper implementation, detect enabling factors and successful aspects of implementation and disseminate best practices in, and barriers to, ISPH implementation with recommendations to policymakers, managers and practitioners.

“A lot of people were saying they don’t
have enough resources to adequately
implement the policy as it is supposed to
be implemented.”

Findings of project in Maluti-a-Phofung area
Janse van Rensburg said the ISHP had various strengths. “People were impressed with the integrated nature of the policy and the way people collaborated across disciplines and departments. The school team were found to work very well with the schools and gel well with the educators and principles.”

He said the main weakness of the implementation was resources. “A lot of people were saying they don’t have enough resources to adequately implement the policy as it is supposed to be implemented.

“Another drawback is the referral, because once you identify a problem with a child, the child needs to be referred to a hospital or clinic.” He means once a child gets referred, there is no way of knowing whether the child has been helped and in many cases there is no specialist at the hospital.

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