1971. Quantifying the environmental implication of cotton-fiber-based nanocrystalline cellulose : a life-cycle assessmentKatja Malovrh Rebec, Janez Turk, Matjaž Kunaver, 2024, original scientific article Abstract: Considering the increasing demand for nanocrystalline-cellulose in the industry, due to its exceptional physical and biological properties, cheaper and more efficient production processes are sought. Addressing environmental concerns, especially within the framework of EU policies, this study employs Life Cycle Assessment (LCA) to evaluate the environmental performance of a novel nanocrystalline-cellulose production procedure, encompassing biomass depolymerization, rinsing, and bleaching. The LCA aims to identify environmental hotspots, explore mitigation measures, and enables comparisons with other LCA studies on nanocrystalline-cellulose. The results are calculated and reported for 19 environmental impact categories, using the ReCiPe 2016 impact assessment method. The production of 1 kg of dry nanocrystalline-cellulose using the novel process emits 63.7 kg CO2 equivalent, which is lower than the literature average (68 kg CO2 equivalent). The solvent (e.g. diethylene glycol) is the major contributor to the global warming potential and fossil-fuel depletion potential in the product stage of the nanocellulose, while the electricity requirements and glycerin represent environmental hotspots regarding 15 of the 19 impact categories assessed. In terms of the water-consumption potential, the environmental hotspot is production of raw materials (e.g. cotton fibers). Electricity contributes more than 50 % of the burden to the impact categories associated with ionizing radiation, the pollution of aquatic ecosystems and human toxicity related to cancer. It also holds a significant share of the burdens for terrestrial acidification (48 % of the impact), the formation of fine particulate matter (46 % of the impact), and human toxicity related to non-cancer diseases (37 % of the impact). This underscores the importance of optimizing the production process, possibly through upscaling. Additionally, incorporating on-site renewable energy sources and utilizing biomass-derived diethylene glycol can enhance the environmental performance of nanocrystalline-cellulose. Keywords: LCA, cascade use, cellulose nanocrystals, pilot production, environmental performance Published in DiRROS: 06.02.2024; Views: 390; Downloads: 199 Full text (5,07 MB) This document has many files! More... |
1972. Elektronske cigarete, ogrevani tobačni izdelki, nikotinske vrečke in brezdimni tobačni izdelki : kaj o teh izdelkih s tobakom ali nikotinom povedo raziskave?Helena Koprivnikar, Jerneja Farkaš-Lainščak, 2023, review article Abstract: V Sloveniji je kajenje tobaka še vedno med najpomembnejšimi preprečljivimi dejavniki tveganja za smrt in na prvem mestu za izgubljena zdrava leta življenja. V Sloveniji in številnih razvitih državah beležimo zniževanje prevalence kajenja. Industrija je za ohranitev oziroma večanje prodaje in dobička dala na trg različne vrste izdelkov s tobakom ali nikotinom, kot so elektronske cigarete, ogrevani tobačni izdelki in nikotinske vrečke, ki so prisotni tudi v Sloveniji. Vse bolj priljubljeni v Sloveniji postajajo tudi brezdimni tobačni izdelki. V bibliografski podatkovni zbirki PubMed smo poiskali sistematične preglede in metaanalize o vplivih na zdravje pri uporabi teh izdelkov, poiskali poročila mednarodnih organizacij o njihovem vplivu na zdravje in okolje ter uporabili najnovejše dostopne podatke iz slovenskih nacionalnih raziskav za prikaz razširjenosti njihove uporabe v Sloveniji. Ogrevani tobačni izdelki, elektronske cigarete in nikotinske vrečke izpostavijo uporabnika znatnim ravnem zdravju škodljivih snovi. Dolgoročni učinki njihove uporabe na zdravje še niso ustrezno raziskani, saj so v uporabi še prekratek čas, dostopni podatki pa kažejo, da imajo škodljive učinke na zdravje, nekateri že kratkoročno, in da bodo verjetno privedli do pomembnih posledic za zdravje pri dolgoročni uporabi. O manjši škodljivosti teh izdelkov v primerjavi s kajenjem cigaret ni možno govoriti, saj je na voljo premalo kakovostnih raziskav, poznani pa so škodljivi učinki dolgoročne uporabe brezdimnih tobačnih izdelkov. Vsi omenjeni izdelki se pogosto promovirajo tudi kot učinkoviti pripomočki za opuščanje kajenja, a tudi na tem področju ni na voljo zadosti kakovostnih raziskav, da bi lahko sklepali zaključke o njihovi vlogi v opuščanju kajenja, zato se jih v te namene ne priporoča. Vsi omenjeni izdelki vsebujejo nikotin (izjema so elektronske cigarete brez nikotina) in uporabnika zasvojijo. Uporaba izdelkov z nikotinom med mladimi pa je povezana še z dodatnimi pomembnimi tveganji; poleg zasvojenosti, ki se razvije hitreje in močneje kot pri odraslih, so tu še škodljivi učinki na razvoj možganov, pri elektronskih cigaretah in brezdimnih tobačnih izdelkih pa tudi zvišano tveganje za kajenje cigaret v prihodnosti. Podatki za Slovenijo kažejo, da uporaba teh izdelkov med mladimi narašča s starostjo ter da med mladimi odstotki uporabnikov večinoma presegajo odstotek med populacijo, starejšo od 25 let. V zadnjih letih odstotki uporabnikov elektronskih cigaret in brezdimnih tobačnih izdelkov med mladostniki naraščajo izraziteje kot med odraslimi. Ključna je čimprejšnja strožja zakonodajna ureditev teh izdelkov, da preprečimo in zmanjšamo njihovo uporabo, predvsem med mladimi. Keywords: tobak, nikotin, elektronski sistemi za dovajanje nikotina, tobačni izdelki, mladostniki Published in DiRROS: 05.02.2024; Views: 479; Downloads: 107 Full text (338,31 KB) |
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1975. Possibilities for improvement of mechanical properties of high-strength medium-carbon SiCr steelsPavel Salvetr, Jakub Kotous, Črtomir Donik, Aleksandr Gokhman, Zbyšek Nový, 2023, original scientific article Keywords: spring steel, 54SiCr6 steel, microstructure, mechanical properties Published in DiRROS: 02.02.2024; Views: 516; Downloads: 175 Full text (1,44 MB) This document has many files! More... |
1976. Austenite reversion suppression with deep cryogenic treatment : a novel pathway towards 3rd generation advanced high-strength steelsPatricia Jovičević Klug, Matic Klug Jovičević, Lars Thormählen, Jeffrey McCord, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, original scientific article Keywords: Martensitic stainless steel, deep cryogenic treatment, microstructure, mechanical properties, microstructural transformations, phase transformation Published in DiRROS: 02.02.2024; Views: 383; Downloads: 185 Full text (13,70 MB) This document has many files! More... |
1977. Hybrid additive manufacturing of Ti6Al4V with powder-bed fusion and direct-energy depositionSimon Malej, Matjaž Godec, Črtomir Donik, Matej Balažic, René Zettler, Thomas Lienert, Laurent Pambaguian, 2023, original scientific article Keywords: hybrid additive manufacturing, Ti6Al4V, tensile properties, defects, microstructure, phase transformation Published in DiRROS: 02.02.2024; Views: 402; Downloads: 188 Full text (18,54 MB) This document has many files! More... |
1978. Evaluation of the impact and fracture toughness of a nanostructured bainitic steel with low retained austenite contentMihael Brunčko, Peter Kirbiš, Ivan Anžel, Leo Gusel, Darja Feizpour, Tomaž Irgolič, Tomaž Vuherer, 2023, original scientific article Keywords: evaluation of fracture toughness, impact toughness, nanostructured bainite, natural aging, low retained austenite content, kinetically activated bainite KAB Published in DiRROS: 02.02.2024; Views: 391; Downloads: 177 Full text (6,44 MB) This document has many files! More... |
1979. Effect of double-step and strain-assisted tempering on properties of medium-carbon steelPavel Salvetr, Andrea Školáková, Jakub Kotous, J. Drahokoupil, Daniel Melzer, Zdeňek Jansa, Črtomir Donik, Aleksandr Gokhman, Zbyšek Nový, 2023, original scientific article Keywords: medium-carbon steel, tempering, strengthening, mechanical properties, microstructure Published in DiRROS: 02.02.2024; Views: 393; Downloads: 171 Full text (9,82 MB) This document has many files! More... |
1980. Effect of Cu alloying on mechanical properties of medium-c steel after long-time tempering at 500 °CPavel Salvetr, Aleksandr Gokhman, Milan Svoboda, Črtomir Donik, Ivana Podstranská, Jakub Kotous, Zbyšek Nový, 2023, original scientific article Keywords: long-time tempering, strengthening, Cu precipitate, medium-C steel, mechanical properties Published in DiRROS: 02.02.2024; Views: 458; Downloads: 183 Full text (6,20 MB) This document has many files! More... |