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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

Getting out of the dark
2015-06-10

 

ESKOM is making daily announcements on the status of the power grid.

Anton Calitz, Electrical Engineer at University Estates, is in continuous contact with Eskom and Centlec in an effort to stay abreast of load shedding.

According to Anton, Eskom has recently - the week of 20 April - been focusing on the evening peak, and has announced STAGE 1 load shedding from 17:00-22:00; thus, the Bloemfontein Campus should be able to continue business as usual during the day, except for Thursdays from 18:00 and, possibly, Fridays from 17:00.

Where can I get more information about load shedding stages?

Apart from Eskom’s webpage, staff can also visit GRID WATCH. Click on "Search", then under "Schedules". Look for "Mangaung Local Municipality", and select "GROUP 4". Save this location. “This can even be loaded onto your mobile device.”

“The time slots can be seen for a couple of days in advance, to allow us to plan around the possibility of load shedding in our daily lives,” said Anton.

Please note: ESKOM can change the STAGE level at any time. Therefore, keep an eye on GRID WATCH and News24.

View the typical seven-day planner for the Bloemfontein Campus (Group 4), which indicates the STAGE 2 and 3 possibilities. Take note that, on some days, the STAGE 2 and 3 time slots are the same.

More load shedding tips: Your IT needs

The UFS Data Centre (Computer Room) is fully serviced by a generator facility, and can function without external power supply for a few days.

The generator servicing the UFS data centre does NOT provide power to the outlying facilities. This implies that all digital equipment at gates, booms, and access points will be shut down until the power is restored to these facilities. “We are now, in collaboration with Nico Janse van Rensburg, in a process to install UPS facilities at these points, which will ensure two to three hours of power supply at these points, even during load shedding,” said Dr Vic Coetzee, Senior Director: ICT Services.

No Wi-Fi will be available, as it is dependent on the power supply to the buildings where it is installed.

All servers are contained in the data centre, and will be kept running by our generators.

How to manage load shedding and your IT needs:

1. Get into the habit of saving your work regularly on computer so that you don’t lose your work/files during load shedding.
2. Back up important data. Keep to a schedule of regular back-up.  Make sure your computer back-ups are safe and recoverable.
3. Keep all electronic devices charged and ready to run on battery power. Keep your cellphone charged: some old-style Telkom landlines will still operate during power outages, but others won't.
4. Remember, when power supply is restored, it sometimes happens that a power surge is sent through the network, which will damage your computer.  Fortunately, laptop computers will not suffer this fate as their power is provided through an external power pack. Often, this power pack will be damaged, but not the laptop itself.
5. It makes good sense to reboot your computer daily, not only in terms of power shedding, but also in terms of updating the drivers, software, etc.
6. Switch off all computers and other electrical equipment at the wall plug overnight and on weekends.
7. Should your IT equipment not switch on after a power outage, log a call with the ICT Services. You can also call them at x2000.

More information, guidelines and contact numbers

 

 

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