Due to escalating pollution, global clean water supplies are becoming seriously threatened and in many countries clean water is a luxury that can unfortunately no longer be taken for granted. The modernization of treatment plants, the critical points of entry of treated water into the environment, and assuring impeccable drinking water sources are therefore essential. An effective water treatment technology that could replace or upgrade the existing systems is urgently needed. The purpose of the presented study is to investigate cavitation as a method that can destruct various microorganisms (bacteria, algae and yeasts) and viruses. We wanted to find out which microorganisms had already been successfully destroyed and what was reported as a mechanism of action: the mechanical or chemical effect of cavitation. Our study serves as the basis for all further research. It is clear from the summary of the reviewed literature that there is a huge amount of inconsistency in this area. Most research has focused on acoustic cavitation, while hydrodynamic cavitation has been at the center of research only the last few decades. It is also evident that there has not been much progress in terms of developing new ways of cavitation generation especially in the case of HC. The biggest problem is that most authors only cite previous assumptions regarding cavitation’s mechanisms of action and they neither investigate nor offer additional and corroborated new possibilities. It is an indisputable fact that we urgently need a technology that would successfully destroy microorganisms and viruses in environmental samples and in food products, without additional negative effects (eg the formation of secondary pollutants). Cavitation could prove to be the technology that would meet all of the above mentioned criteria, but in order to use it in the most efficient way, it is necessary to explore in detail the mechanisms responsible for its effects. This can only be achieved if a group of scientists from different scientific fields undertakes the research, which is the essence of the ERC project CABUM.?
COBISS.SI-ID: 16633627
Refining of cellulose pulp is a critical step in obtaining high quality paper characteristics, however, this process is slow and costly especially for refining longer conifer fibers which are the preferred source for high quality paper production and give the paper its strength. In this study, we have applied a novel rotation generator of hydrodynamic cavitation for refining conifer rich pulp samples. Our results show that the device is capable of generating intense shear forces and multiple zones of developed cavitation and is successful in increasing the drainage rate of high consistency pulp. The paper produced by means of the obtained pulp has higher quality because of its higher tensile and burst strengths. In addition, this laboratory scale rotation generator proved to be economically efficient in comparison to the routinely employed laboratory beaters. Further development of the device will lead to a more energy efficient, cost effective and environmentally sustainable paper production processes.
COBISS.SI-ID: 514097195
The research envelopes the combustion analysis of a highly oxygenated, viscous and economically viable fuel in an internal combustion micro gas turbine. It presents a continuation of series of achievements on highly viscous waste derived fuels. Results suggest that the use of highly oxygenated fuels might have environmental benefits in terms of NOx emissions and PM emissions are significant as concentrations of both species are reduced. Based on the analysis presented in the study, altered local air-fuel ratio suppresses NOx formation and PM formation resulting in 10-fold lower PM emission than same experimental apparatus with diesel fuel. The study further analyses and identifies three key mechanisms that are responsible for this reduction: altered oxygen profile during mixture preparation, prevention of soot precursors formation and promotion of soot oxidation reactions. Significant benefits of the fuel in terms of environmental impact indicate that oxygenated fuels could exhibit an increased resistance to soot formation, leading to an opportunity to exploit them in innovative combustion concepts relying on substantial dilution of the mixture (for example high EGR applications). Further investigation and development of this hypothesis might provide a new alternative energy source for stationary use as well as for mobility with significant benefits in terms of emission reduction. The achievement for the first time reveals an important opportunity to exploit synergistic effects of oxygenated fuels and advanced combustion concepts. Hence, it opens a new research field with high relevance when coupled to carbon neutral fuels and available power generation technology.
COBISS.SI-ID: 16434459
With a recent paradigm shift and substantial research activities in the area of renewable fuels of non-biological origin, the programme group initiated the investigations in ammonia combustion. The first step in this direction envelopes the presented fundamental research that investigates the possibility to use ammonia-hydrogen blends in a humidified cycle turbine with the aim to maintain high efficiency, comparable to that of conventional dry-low NOx technologies using methane. By using CHEMKIN-PRO reaction networks, novel chemical reaction kinetics, all supported by experimental investigation using steam injection, the research proved that it is possible to obtain stable flames with such approach and that the investigated direction is opening a new opportunity for further investigation of the topic. The research presents an important starting point for ammonia combustion research in the programme group since it is possible to fully experimentally evaluate ammonia combustion also in existent research infrastructure.
COBISS.SI-ID: 16625691
The chemical potential of lithium in LixFePO4 active cathode nanoparticles and the surface free energy between LixFePO4 and electrolyte were determined with the novel thermodynamically consistent application of the regular solution theory. Innovative consideration of crystal anisotropy accounts for the consistent determination of the dependency of the chemical potential on the mechanistically derived enthalpy of mixing and the phase boundary gradient penalty. This enabled the analytic, thermodynamically consistent determination of the phase boundary thickness between LiFePO4 and FePO4, which is in good agreement with experimental observations. The obtained explicit functional dependency of the surface free energy on the lithium concentration enables adequate simulation of the initiation of the phase transition from FePO4 to LiFePO4 at the surface of active cathode particles. To validate the plausibility of the newly developed approaches, lithium intercalation into the LixFePO4 nanoparticles from electrolyte was modeled by solving the Cahn-Hilliard equation in a quasi-two dimensional domain.
COBISS.SI-ID: 16474651