Jakub Rolný's master thesis will certainly not end up in a drawer. Now a graduate of the Faculty of Mechanical Engineering at the BUT, he has created a laboratory device for sampling seeds of various sizes and shapes. The representative samples created in this way will then be used by experts from the Julius Kühn Institute (German Federal Research Centre for Cultivated Plants) for further research.
Claudia Beleites came to Brno for Jakub's thesis defense in June. The analytical chemist, who is dedicated to chemometrics, had been solving the problem of how to prepare seed samples for examination in the laboratory for some time. "Let's take the breeding of caraway as an example: you have some sort of caraway bred for oil content and you need to do a reference analysis and check whether the seeds you got have the properties you need. This is done in the Plant analysis lab," says Claudia Beleites.
The laboratory receives samples of plant material, but they can vary a lot: sometimes it´s cocoa beans to be analyzed, which are moderately large, sometimes the aforementioned caraway or the tiny flakes of destemmed oregano. 'In layman's terms, you get a bag full of material and you need to prepare a representative sample. But the materials tend to segregate – the heavier stuff goes down, the lighter stuff goes to the surface. It's surprisingly difficult to prepare, say, a two-gram sample from a kilogram of material that is still representative of the whole and reflects the overall composition so that we can draw scientific conclusions from its analysis," explains Beleites.
Devices called sample dividers exist on the market. They are built to sample a single plant, or rather uniformly sized and shaped seeds. A universal tool that reflects the needs of the lab has been lacking. Coincidence helped: when Claudia Beleites met Pavel Škrabánek from the Faculty of Mechanical Engineering of the BUT at the conference, the idea came up that one of his students could design and build the device.
The challenge was accepted by Jakub Rolný, a student of Applied Computer Science and Control. And it wasn't easy. " There is no lecture course about sampling theory or related topics. The student had to study it all by himself to be able to solve the problem," says Škrabánek, who supervised Jakub's thesis.
"I was interested in the topic because it required both software development and mechanical construction. The mechanical part was ultimately the biggest challenge, plus matching it with the software to make everything work as it should," says Jakub Rolný, pointing to a device roughly the size of a cubic meter. "The input material goes into the hopper here and inside it, the narrowest possible strip of material is then produced, which is sampled at the end of the conveyor belt. A representative sample is then produced using this flap. The software controls the entire system, from switching the conveyor on and off, to the size of the material being conveyed, the speed of the belt, and the frequency of the flap," says Rolný.
After successfully passing the state examinations Jakub Rolný left for Germany for a Short Term Scientific Mission of 10 days of on-site research with Claudia Beleites and the sample divider with a travel grant by the EU COST action CA19145 (SensorFINT). "The aim is to fine-tune the equipment on site and test it on different materials," adds Rolný. Claudia Beleites is also looking forward to the new helper. " The most important thing is that you get a splitting quality, that you will not reach by hand. That's because humans have an amazing capacity to pick out good things. When you do the sample division manually this will never be a representative split," she says. And adds: " There's a whole theory of sampling that that describes what to do and what to not do. One of the important findings of that work is that any kind of uncertainty or error that you get in the sub-sampling process can never be corrected afterward. So it's important to get it right there and that's the main thing of this instrument – it helps to get it right," Beleites is delighted.