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Abstract: Efflorescence, a time-dependent and water-driven phenomenon, is a major concern inalkali-activated materials (AAMs), impacting their practical use and preservation in a time-frozen state for post-characterisation. Although a method for stopping chemical reactions in conventional cements exists, it is time-consuming and not chemical-free. Therefore, this study explored the effects of low-power microwave-induced dehydration on efflorescence, mechanical performance, and structural integrity in AAMs, to create an alternative and more “user-friendly” dehydration method. For this purpose, several mixtures based on secondary raw (slag, fly ash, glass wool, and rock wool) and non-waste (metakaolin) materials were activated with a commercial Na-silicate solution in ratios that promoted or prevented efflorescence. Characterisation techniques, including Fourier-transform infrared spectroscopy and X-ray diffraction, showed that microwave dehydration effectively removed water without altering crystallinity, while mercury intrusion porosimetry and compressive strength tests confirmed increased porosity. In addition to being an efficient, time-saving, and solvent-free manner of stopping the reactions in AAMs, microwave irradiation emerged as an innovative, chemical-free method for evaluating curing finalisation and engineering foams in a stage when all other existing methods fail. However, the artificially provoked efflorescence in aged dehydrated AAMs connected the slipperiness of AAM with the instant extraction of Na, which raised the need for further research into alternative alkali replacements to evaluate the practical use of AAM.
Keywords: materials chemistry, alkali-activated materials, geopolymers, slag, fly ash, rock wool, glass wool, metakaolin, microwave irradiation, dehydration, stopping chemical reactions, efflorescence
Published in DiRROS: 23.12.2024; Views: 101; Downloads: 41
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Abstract: The complicated dance between the decision-making (hereinafter: DM) process, which is shaped by the individual psychological constructs and internal cognitive processes, and the methodological process of strategic management (hereinafter: SMP), which can be understood as a framework that defines decision context, raises pertinent questions about their coherence. The purpose of this study is to propose an integrative model of the strategic decision-making process (hereinafter: SDM), which links the cognitive processes of decision-makers with the rigour of strategic management and identifies and mitigates potential risks at each stage of the holistic process. To design the research, we used the "model paper" approach which seeks to build a theoretical framework that predicts relationships between research concepts. The developed comprehensive model connects four independent concepts, creating a holistic framework for SDM in organizations. The comprehensive model reveals a high degree of consistency between the SMP, knowable decision-making cycle and cognitive processes. Throughout the entire process, decision-makers need to be mindful of the interplay between System 1 and System 2 thinking. While System 1 thinking may provide quick insights and initiate creative thinking, it is important to complement it with the deliberate and analytical reasoning of System 2 thinking, which can be supported by a proper application of different strategic management tools and methods.
Keywords: strategic management process, decision making process, integrative concept, strategic decision making, system 1 and 2 thinking
Published in DiRROS: 23.12.2024; Views: 97; Downloads: 29
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Abstract: Metasekvoja (Metasequoia glyptostroboides Hu et Cheng) je ena najpozneje odkritih drevesnih vrst na Zemlji in hkrati zelo stara vrsta, ki se morfološko skozi milijone let skoraj ni spremenila. Odkrita je bila šele sredi 20. stoletja na Kitajskem, le nekaj let za tem, ko so znanstveniki odkrili njene fosilne ostanke in predvidevali, da gre za izumrlo vrsto. Po odkritju se je o metasekvoji veliko govorilo in pisalo, sadili so jo po vsem svetu z namenom preučevanja, saj je bilo odkritje živih osebkov senzacija za ves botanični svet. Danes se je v luči podnebnih sprememb in ob iskanju novih možnosti za večjo odpornost gozda metasekvoja kot potencialno uporabna vrsta zopet znašla pod drobnogledom. Njeno močno užlebljeno deblo in obstojnost odmrlih vej lahko predstavljajo težavo pri obdelavi njenega proti glivam sicer zelo odpornega lesa, hkrati pa zaradi edinstvenega videza deluje izredno estetsko predvsem v urbanem okolju. Kot gospodarsko vrsto jo uporabljajo ponekod na Kitajskem, v Evropi jo sadijo predvsem v testnih nasadih in v urbanem okolju. V preglednem prispevku je po sedmih desetletjih prisotnosti metasekvoje v Sloveniji podrobneje predstavljena zgodovina njenega odkrivanja, dosedanja uporaba in ocenjen je njen prihodnji potencial.
Keywords: Slovenija, Metasequoia glyptostroboides, zgodovina, odkritje, lastnosti, drevesne vrste
Published in DiRROS: 22.12.2024; Views: 192; Downloads: 31
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Keywords: wild populations, landraces, Brassica, genetic diversity, taxonomic verification
Published in DiRROS: 20.12.2024; Views: 88; Downloads: 19
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Keywords: extracellular particles, extracellular vesicles, exosomes, membrane vesiculation, platelets, blood products, platelet-rich plasma, liquid biopsy, membrane enclosed, drug delivery
Published in DiRROS: 20.12.2024; Views: 91; Downloads: 33
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