1. Solidification of gelatine hydrogels by using a cryoplatform and its validation through CFD approachesYasir Beeran Potta Thara, Miha Jordan, Timi Gomboc, Blaž Kamenik, Boštjan Vihar, Vanja Kokol, Matej Zadravec, 2022, original scientific article Abstract: In this work, we developed a numerical approach based on an experimental platform
to determine the working conditions on a cryoplatform and to predict and evaluate the cryogenic
printing of hydrogels. Although hydrogels have good biocompatibility, their material properties
make it difficult to print them with high precision and shape fidelity. To overcome these problems, a
cryogenic cooling platform was introduced to accelerate the physical stabilisation of each deposited
layer during the printing process. By precisely controlling solidification (crystallisation), each printed
material can withstand its own weight to maintain shape fidelity, and the porosity of the scaffolds
can also be controlled more selectively. The thermophysical properties of gelatine hydrogels were
investigated to gain a better understanding of the phase change upon freezing. The corresponding
material properties and experimental observations of gelatine solidification served as the basis for
developing a computational fluid model (CFD) to mimic the solidification of gelatine hydrogels
using a cryoplatform at different process conditions and extruder speeds. The goal was to develop a
tool simple enough to predict acceptable process conditions for printing gelatine hydrogels using
a cryoplatform.
Keywords: gelatine, hydrogel, cryoprinting, CFD simulation, solidification modelling
Published in DKUM: 20.03.2025; Views: 0; Downloads: 7
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2. Reconstruction of a fluid bed device for separating granular material from the grinding process of rapid antigen testsMiha Jordan, Tilen Švarc, Peter Majerič, Rebeka Rudolf, Matej Zadravec, 2023, original scientific article Abstract: The article includes the study and reconstruction of a fluid bed device with the purpose of separating the granular material from the grinding process of rapid antigen tests. The following techniques were performed, with the purpose of characterisation of the ground particles: sieve analysis, X-ray fluorescence spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The paper includes experimental testing of a simplified separation process with zeolite spheres and paper strips, supported by a numerical model. The flow conditions’ impact on the behaviour and interactions of particles of the considered problem were simulated using coupled computational fluid dynamics (CFD) and the discrete element method (DEM) approach. The separation process of zeolite spheres and paper strips was found to be efficient. The simulation results showed the appropriate behaviour of the particles during the process. We explained the results’ deviations, and we also presented the shortcomings and possible improvements. Further research is required to define the adequacy of the process, while using actual ground material of rapid antigen tests.
Keywords: rapid antigen tests, nanomaterials, fluidised bed, computational fluid dynamics, discrete element method, characterisation
Published in DKUM: 05.01.2024; Views: 378; Downloads: 57
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3. Rekonstrukcija naprave za lebdeči sloj z namenom separacije mlevine hitrih antigenskih testov : magistrsko deloMiha Jordan, 2023, master's thesis Abstract: Magistrsko delo obsega študij ter rekonstrukcijo naprave za lebdeči sloj z namenom ločevanja mlevine hitrih antigenskih testov. Z namenom karakterizacije mlevine so bile izvedene sledeče tehnike: sejalna analiza, rentgenska fluorescenčna spektrometrija, vrstična elektronska mikroskopija, energijsko disperzijska spektroskopija rentgenskih žarkov ter presevna elektronska mikroskopija. Zaključno delo zajema eksperimentalno testiranje poenostavljenega procesa separacije z zeolitnimi kroglicami in papirnatimi lističi, podkrepljeno z numeričnim modelom. Tokovne razmere obravnavanega problema so bile simulirane s pomočjo računalniške dinamike tekočin (RDT), obnašanje ter interakcije delcev pa z metodo diskretnih elementov (DEM). Ugotovljeno je bilo, da je proces ločevanja zeolitnih kroglic in papirnatih lističev učinkovit. Rezultati simulacije so pokazali ustrezno obnašanje delcev tekom procesa. Odstopanja rezultatov so razložena, predstavljene pa so tudi pomanjkljivosti ter možne izboljšave. Za opredelitev ustreznosti procesa ob uporabi dejanske mlevine hitrih antigenskih testov bi bilo potrebno nadaljnje raziskovalno delo.
Keywords: hitri antigenski testi, nanomateriali, krožno gospodarstvo, lebdeči sloj, računalniška dinamika tekočin, metoda diskretnih elementov
Published in DKUM: 22.09.2023; Views: 490; Downloads: 94
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