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TED Talks about rainbows

18 April 2022 | Story Leonie Bolleurs | Photo Stephen Collett

“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

Guest lecture: Mr Pretorius, CEO of McCarthy Limited

2004-11-05

The challenges facing business leaders in a rapidly changing South Africa

“The world we used to know does not exist anymore. Leaders are continually dealing with crisis and opportunities, in a high-pressure environment,” said Mr Brand Pretorius, honorary professor from the University of the Free State , delivering his 13th guest lecture on the challenges facing business leaders in a rapidly changing South Africa .

Mr Pretorius, CEO of McCarthy Limited, identified certain trends which are responsible for changes to the South African business environment. He said the South African business environment is ever-changing, fast moving, complex and unpredictable. “As business people we have to deal with the impact,” he said.

“Years ago we were globally isolated. Now we live in a shrinking borderless world with crumbling trade barriers. Globilisation of our economy is accelerating. For South African business leaders this creates a sea of export opportunities,” he said.

Although there are ongoing demands for substantial profit growth from shareholders, the days of focussing only on their interests are gone, said Mr Pretorius. Stakeholder commitment now enjoys high priority and business leaders have to deal with the challenges accompanying black economic empowerment and employment equity.

Customers are also well-informed and demanding. Business leaders could easily loose the loyalty of their customers because of a hyper-competitive environment with an oversupply of goods and services.

Mr Pretorius stated that staff want to be involved and are looking for meaning in their workplace. Employers also have to deal with HIV/Aids in their workplaces. Trauma, absenteeism and financial implications could have a great effect on the viability of a business.

Against these changes Mr Pretorius pointed out the challenges business leaders are facing. In doing so a number of questions arise. The external business climate is characterised by turbulence and change. Internally there is a need for stability and meaning. How do we handle both challenges effectively?

Because of changes strategy decay is taking place and past strategies become irrelevant. Mr Pretorius said that business leaders need to modify their business models to prevent the downfall of their companies.

It is important for leaders to know what is happening in their world. “Continuous innovation is a critical success factor. The reality is that innovation is the only insurance against irrelevance,” he said.

Because of a changed environment leaders must perform and transform, simultaneously. How do we strike a balance between focused transformation and the achievement of world class performance, asked Mr Pretorius? “We need to bring about meaningful and sustainable empowerment, in order to create an inclusive economy and society. Leadership and management profiles should reflect the diversity of our teams, however at the same time every effort should be made to stop the brain drain and retain the expertise of experienced white managers.”

He also stated that leaders have an important role to play in terms of employment creation and corporate caring. “Sustainable stability and prosperity will not materialise without efforts in this regard.”

Mr Pretorius said that above challenges could be addressed by developing the ability to focus on creating a better future, rather than defending the past, a long-term vision, facing new realities, enhancing the value of brands and mobilising IT and the Internet to serve the business and customers better.

Retaining a positive vision of the future, embracing change and transformation, building your business according to the right principles and values and aspiring to be the best are some of the guidelines, according to Mr Brand, for future business success. He stated that creating a value advantage above one’s competitors, customer satisfaction and retention and inspirational leadership will add to the success of one’s business.

“We are indeed living in the era of the ultimate challenges, but also the ultimate opportunities. Let me clearly state that I have hope – in my view the tide has turned. Every day I experience small miracles inspired by ordinary people making an extraordinary difference,” said Mr Pretorius.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
5 November 2004

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