1. Hydrothermal decomposition of virgin and waste polylactic acid with subcritical water under N[sub]2 and air atmospheresMaja Čolnik, Mihael Irgolič, Mojca Škerget, 2025, izvirni znanstveni članek Opis: This study addresses the inherent shortcomings of poly (lactic acid) (PLA), a biodegradable polymer widely used in industries such as packaging and biomedical applications. The principal challenge of PLA resides in its low crystallinity, which detrimentally affects its mechanical properties and thermal stability. Additionally, PLA is prone to water and hydrolysis, which compromises its chemical resistance and can lead to degradation over time. To overcome surmount these limitations, the study focuses on the development of hybrid films through the blending of PLA with poly (l-lactide-co-ethylene adipate) (pLEA) block copolymers. The objective is to augment the crystallinity, mechanical performance, and chemical resistance of the resulting materials. The study employs a range of analytical techniques, including Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Polarised Light Microscopy (PLM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA), to thoroughly characterize the copolymers and blend films. By systematically selecting blending ratios and processing methodologies, the study demonstrates enhancements in the properties of the resultant hybrid films compared to neat PLA. Specifically, the structure of films significantly changed from amorphous to crystalline in a short duration - 5 min, of annealing., leading to better tensile strength, modulus and reduced wettability, which are crucial for applications requiring durability and resistance to environmental factors. Films made from 30 wt% of pLEA 97.5/2.5 with 70 % of PLA by fast cooling exhibited outstanding mechanical properties, with a tensile strength 20 MPa higher than that of neat PLA films. Additionally, the chemical resistance may be improved, as evidenced by a decrease in wettability by approximately 15° and a reduction in the polar component of the surface free energy by about 7 mN/m. Hydrophobic, water-repellent materials resist penetration by water and other polar solvents, reducing exposure to corrosive substances and enhancing chemical resistance through barrier protection. Overall, this research addresses the limitations of PLA through innovative copolymerization and blending strategies, offering valuable insights into optimizing the material's properties for various practical applications.
Ključne besede: biopolymers recycling, polylactic acid, subcritical water, lactic acid, carboxylic acids, gaseous products
Objavljeno v DKUM: 01.04.2025; Ogledov: 0; Prenosov: 1
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2. An embedding of the Cantor fan into the Lelek fanIztok Banič, Goran Erceg, Judy A. Kennedy, 2025, izvirni znanstveni članek Opis: The Lelek fan L is usually constructed as a subcontinuum of the Cantor fan in such a way that the set of the end-points of L is dense in L. It easily follows that the Lelek fan is embeddable into the Cantor fan. It is also a well-known fact that the Cantor fan is embeddable into the Lelek fan, but this is less obvious. When proving this, one usually uses the well-known result by Dijkstra and van Mill that the Cantor set is embeddable into the complete Erdős space, and the well-known fact by Kawamura, Oversteegen, and Tymchatyn that the set of end-points of the Lelek fan is homeomorphic to the complete Erdős space. Then, the subcontinuum of the Lelek fan that is induced by the embedded Cantor set into the set of end-points of the Lelek fan, is a Cantor fan. In our paper, we give an alternative straightforward embedding of a Cantor fan into the Lelek fan. We do not use the fact that the Cantor set is embeddable into the complete Erdős space and that it is homeomorphic to the set of end-points of the Lelek fan. Instead, we use our recent techniques of Mahavier products of closed relations to produce an embedding of the Cantor fan into the Lelek fan. Since the Cantor fan is universal for the family of all smooth fans, it follows that also the Lelek fan is universal for smooth fans.
Ključne besede: closed relations, Mahavier products, fans, Cantor fans, Lelek fans
Objavljeno v DKUM: 04.03.2025; Ogledov: 0; Prenosov: 5
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3. Chaos and mixing homeomorphisms on fansIztok Banič, Goran Erceg, Judy A. Kennedy, Christopher Mouron, Van Nall, 2024, izvirni znanstveni članek Opis: We construct a mixing homeomorphism on both the Lelek fan and the Cantor fan. We also construct a family of uncountably many pairwise non-homeomorphic smooth (and non-smooth) fans that admit mixing homeomorphisms.
Ključne besede: closed relations, Mahavier products, transitive dynamical systems, transitive homeomorphisms, mixing homeomorphisms, smooth fan
Objavljeno v DKUM: 26.02.2025; Ogledov: 0; Prenosov: 2
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4. Modeling and optimization of anaerobic digestion technology : current status and future outlookTina Kegl, Eloisa Torres Jiménez, Breda Kegl, Anita Kovač Kralj, Marko Kegl, 2025, pregledni znanstveni članek Ključne besede: renewable energy, anaerobic digestion, biogas plant, mathematical models, optimization algorithms, products utilization
Objavljeno v DKUM: 31.01.2025; Ogledov: 0; Prenosov: 13
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5. Energy demand distribution and environmental impact assessment of chitosan production from shrimp shellsFilipa A. Vicente, Robert Hren, Uroš Novak, Lidija Čuček, Blaž Likozar, Annamaria Vujanović, 2024, izvirni znanstveni članek Opis: Step towards resilience and sustainability through exploring renewable biomass and waste streams to produce higher-added value products and energy is among key aspects for closing the loops, saving resources, and reducing the resource and emission footprints. In that respective, crustacean shells waste can offer rich spectre of valuable compounds such as proteins, chitin, carotenoids. This waste is produced in large quantities worldwide, thus allowing for commercial valorisation. An overview of technologies is undertaken for more sustainable and environmentally friendly chitosan production via chitin isolation and conversion and compared to the conventional processes. Furthermore, an assessment of the environmental burden and energy demand distribution for conventional and more sustainable alternative processes was performed, based on lab-scale experimental data. Three different chitin extraction routes and three distinct chitosan conversion processes were considered and compared for their greenhouse gas footprint, abiotic depletion, acidification, eutrophication and other potentials. Finally, the energy demand distribution was analysed considering electricity production patterns from three European countries, Slovenia, Portugal and Norway. The results showed that alternatives 3-A and 3-B (conventional eco-solvents - conventional deacetylation with 40 % and 50 % NaOH) generate the lowest environmental burden (184 g CO2 eq./g chitosan). Electricity was the main hotspot of the processes, used either for extraction, plasma treatment or deacetylation. The sensitivity analysis proved that the Norwegian electricity mix has the lowest environmental impact (4.2 g CO2 eq./g chitosan). This study highlights the impact of blue biorefineries by transforming marine waste to valuable biopolymers such as chitin and chitosan.
Ključne besede: shrimp shells waste, blue biorefinery, value-added products, chitosan, sustainable production, comparative environmental assessment
Objavljeno v DKUM: 08.01.2025; Ogledov: 1; Prenosov: 5
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6. The effect of supplementing pig diet with chestnut wood extract or hops on fresh meat and dry-cured productsUrška Tomažin, Martin Škrlep, Maja Prevolnik Povše, Nina Batorek Lukač, Danijel Karolyi, Matjaž Červek, Marjeta Čandek-Potokar, 2020, izvirni znanstveni članek Opis: Oxidation is one of the major reasons for impaired quality of meat and meat products but can be prevented by the addition of antioxidants. In the present study, the effect of dietary sweet chestnut wood extract and hop cones on the quality and oxidative stability of meat and dry-cured products was investigated. Control pigs (N = 11) were fed a commercial diet (13.1 MJ metabolizable energy, 15.5% crude protein), while the other two experimental groups were supplemented with 3% of sweet chestnut wood extract (Tannin; N = 12) or 0.4% of hop cones (Hops; N = 11). The quality of meat and dry-cured products was evaluated by means of chemical composition, water holding capacity, objective color, and lipid and protein oxidation. No major effects of sweet chestnut wood extract or of hops supplementation were observed, nevertheless, some indications of improved water holding capacity could be attributed to antioxidants supplementation. The color evolution of dry-cured bellies from Tannin and Hops groups of pigs during refrigerated storage was also indicative of an improved oxidative stability.
Ključne besede: pig meat, meat quality, pig diet, tannin extract, hops, dry-cured products, oxidation, pigs
Objavljeno v DKUM: 23.12.2024; Ogledov: 0; Prenosov: 4
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7. Perspectives in the beekeeping value chain : innovationand development in the northern region of ColombiaJalelys L. Leones-Cerpa, Martha Cuenca Quicazán, Juan F. Restrepo, Katherine Velandia, Eduardo Sánchez-Tuirán, Karina A. Ojeda, 2024, izvirni znanstveni članek Opis: Colombia and its regions have abundant botanical wealth and climatic conditions suitable for the development of beekeeping. The Caribbean region is promoting the practice of beekeeping as an activity with benefits to ecosystems, human health, and socioeconomic positioning. The objective of this research is to determine the state of beekeeping in the Colombian Caribbean region and the areas where it is necessary to make improvement actions. The methodology was carried out following bibliographic reviews in databases and government reports, and the surveys were applied through Google Forms. The main results showed the need for more regulations in beekeeping and derived products, the low development of value-added products in the Caribbean region, as well as few technologies for the management of apiaries and the genetic manipulation of bees. The surveys of beekeepers corroborated their perception of some of the areas in which the beekeeping sector requires research and development.
Ključne besede: Colombian Caribbean region, genetic improvement, honey, value-added products
Objavljeno v DKUM: 01.10.2024; Ogledov: 0; Prenosov: 6
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8. Assessment of concept between rural development challenges and local food systems : A combination between Multi-criteria decision analysis and econometric modelling approachJernej Prišenk, Jernej Turk, 2022, izvirni znanstveni članek Opis: This study investigates the influence of social, economic, and environmental impacts on the promotion and marketing systems of local food products from mountain areas in Slovenia. These impacts were assessed using an econometric modelling approach. Two econometric models were developed (one for production and one for marketing). The case studies of local food products were selected from Slovenian mountain regions, most of which were from less-favored areas (LFAs). A majority of the selected food commodities were of high quality, with or without protected designations. Data collection was carried out via interviews. Due to production limitation on mountain areas in Slovenia and other constraints in LFAs, the socio-economic and environmental impacts on success of production and marketing systems need to be clarified. These relations present a potential impact on the wider socio-economic development in the region. The empirical results, obtained using an econometric modelling approach, clearly show the importance of encouraging the socio-economic and environmental impacts in ensuring the marketing and production potentials of local food products. The result express good relationships, and cooperation between the actors in the food supply chains contributing to a successful marketing system and production system of local food products (small, average, large) is dependent on the available local labour in mountain rural areas.
Ključne besede: local food products, mountain areas, econometric modelling, socioeconomic impacts, evironmental impacts
Objavljeno v DKUM: 02.07.2024; Ogledov: 117; Prenosov: 12
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9. AOP-based transformation of abacavir in different environments: evolution profile of descyclopropyl-abacavir and in silico toxicity assessment of the main transformation productsEleni Evgenidou, Konstantina Vasilopoulou, Lelouda-Athanasia Koronaiou, George Z. Kyzas, Dimitrios Bikiaris, Dimitra A. Lambropoulou, 2023, izvirni znanstveni članek Ključne besede: abacavir, antiviral drug, AOPs, transformation products, ECOSAR, evolution profiles
Objavljeno v DKUM: 05.04.2024; Ogledov: 276; Prenosov: 13
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10. Inclusive regional value chains: blockchaining perishable agricultural products in Southern AfricaHamisi K. Sama, 2023, izvirni znanstveni članek Opis: In Southern Africa due to unsystematically and uncoordinated regional value chain (RVCs), plenty of perishable agricultural products are lost because of spoilage and poor postharvest system misaligning upstream and downstream partners. Although appeal for increasing trade in Southern Africa region may seem plausible, there are strictly speaking no well-grounded economic reasons why perishable agricultural products trade should be an obsession. Broad-based inclusive RVCs through blockchaining perishable agricultural products could enable far more effective responses to region’s sustainable developmental challenges as it does in developed and emerging economies. Recently, the rise and expansion of inclusive RVCs and emphasis on blockchain has spurred major paradigm shift on revamping postharvest system. The investigate relevance of blockchaining initiatives towards inclusive RVCs to perishable agricultural products in Southern Africa. Through a quantitative research approach involving quantitative data collection methods, the research aims to assess the current challenges, opportunities, and perceptions regarding blockchain technology in the agricultural sector. Study findings practically and empirically contribute to excel blockchain for supporting development of inclusive and resilient value chains, providing insights for policymakers and stakeholders in promoting sustainable economic growth in Southern Africa's agricultural sector.
Ključne besede: inclusive regional value chain, blockchain, perishable agricultural products
Objavljeno v DKUM: 20.03.2024; Ogledov: 244; Prenosov: 17
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