Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
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

Shack study holds research and social upliftment opportunities
2015-02-10

Photo: Stephen Collett

When Prof Basie Verster, retired head of the Department of Quantity Surveying at the University of the Free State (UFS), initiated an alternative form of housing for Johannes - one of his employees - a decision was made to base research on this initiative. This research project in Grasslands, Heidedal focused on the cost and energy efficiency of green and/or sustainable shacks.

Esti Jacobs from the Department of Quantity Surveying, together with an honours student in Quantity Surveying, a master’s student in Architecture, and young professionals at Verster Berry, helped with the project.

The physical goals of the project were to create a structure that is environmentally friendly, and maintains a comfortable interior climate in winter and summer, as well as being cost-effective to erect. The structure also had to be socially acceptable to the family and the community.

“The intention was to make a positive contribution to the community and to initiate social upliftment through this project. Structures such as the ‘green shack’ may serve as an intermediate step to future housing possibilities, since these structures are relatively primitive, but have economic value and could be marketable,” she said.

Esti explains the structure of the building, which consists of gum poles and South African pine bearers, with a timber roof and internal cement block flooring. The building is clad with corrugated iron and has a corrugated iron roof finish. Additional green elements added to the structure were internal Nutec cladding, glasswool insulation in walls, internal gypsum ceiling boards with ‘Think Pink’ insulation, internal dividing wall and door, polystyrene in the floors, and tint on the windows. A small solar panel for limited electricity use (one or two lights and electricity to charge a cellphone) and a Jojo water tank for household consumption by the inhabitants were also installed.

Esti said: “Phase one of the research has been completed. This phase consisted of an investigation into the cost of an alternative form of housing structure (comparing traditional shacks with the planned structure) as well as the construction process of the physical housing structure.

“Phase two of the research, commencing in February 2015, will last for two to three years. This phase will include the installation of temperature and relative humidity logging devices inside the existing traditional shack and the new green shack. The logs will be regularly monitored by the UFS Department of Quantity Surveying and Construction Management.

These data will enable the researchers to measure the differences in comfort levels inside the two different structures. The data, together with other information such as building materials and methods, are then processed by software programs. Through the simulation of different environments, building materials, and alternate forms of energy, software models can be used to come up with conclusions regarding more energy-friendly building materials and methods. This knowledge can be used to improve comfort levels within smaller, low-cost housing units.

The UFS will be working with Prof Jeff Ramsdell of the Appalachian State University in the USA and his team on the second phase of the project.

“This research project is ongoing and will be completed only in a few years’ time,” said Esti.

The results of the research will be published in accredited journals or at international conferences.

 

For more information or enquiries contact news@ufs.ac.za.

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept