1. The environmental and biodiversity impacts of a new cableway system : a comprehensive life cycle assessmentAnnamaria Vujanović, Andrea Mio, Rok Pučnik, Nicola Blasuttigh, Damjan Krajnc, Maurizio Fermeglia, 2024, izvirni znanstveni članek Opis: Cars are still used as the primary mode of transportation for daily commuting, with their emissions significantly affecting urban air quality, contributing to overall greenhouse gas emissions. Efforts to reduce car dependency have led to exploration of alternative transportation options such as cableway systems in urban areas. However, limited information exists regarding the environmental impacts and biodiversity implications of such systems. This study conducted a comparative life cycle assessment between a proposed cableway system for the city of Trieste, Italy and its current car transportation mode. The analysis considered both daily operational profiles and passenger occupancy rates of the cableway system. Drawing from similar cableway systems worldwide, it was calculated that the proposed Trieste cableway would accommodate 2007 daily passengers, on average. Results from the environmental assessment revealed that the cableway's operational phase had by far the greatest impact on all environmental categories, followed by its construction and by land clearance. Additionally, the use phase was found to be the major cause for most biodiversity loss, particularly towards terrestrial ecosystems. Comparisons of life cycle GHG emissions between the cableway and car transportation indicated that the cableway system would be a preferable option if the daily average passengers would reach at least 3,908, which is almost double than the expected ones. Furthermore, the cableway system exhibited larger environmental impacts across most categories compared to current car transportation. Thus, this study challenges the perception that the cableway system is a more sustainable option compared to conventional modes of transport, as additional factors need to be considered for a broader overview of the environmental performances.
Ključne besede: life cycle assessment, cableway, ropeway, urban, biodiversity, carbon footprint
Objavljeno v DKUM: 23.04.2025; Ogledov: 0; Prenosov: 1
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2. Maximizing the power output and net present value of organic rankine cycle: application to aluminium industryMonika Dokl, Rok Gomilšek, Lidija Čuček, Ben Abikoye, Zdravko Kravanja, 2022, izvirni znanstveni članek Opis: This study presents an integrated design and optimization of an Organic Rankine Cycle (ORC) for the recovery of waste heat from aluminium production. Non-Linear Programming (NLP) models were developed, with the objectives of maximizing electricity production and the Net Present Value (NPV) of the system. The models account for optimizing the operating conditions and changes in thermodynamic features of the system. The developed models are applied to a case study of Slovenian aluminium company where the performance of three different working fluids (R245fa, R1234yf and R1234ze) are compared. The optimization is performed considering different temperatures and prices of produced hot water and electricity, minimum approach temperature (DTmin), concentration of CO2 in flue gas and temperature and flowrate of flue gas. Results show that the selected working fluids for the proposed waste heat-based ORC system have the potential to substitute up to about 830 kW of electricity in a sustainable and economic manner. Out of the three working fluids considered, R245fa showed up to 7.9% efficiency of the ORC cycle and was identified as the best performing working fluid considering both economic viability and the amount of electricity produced by the system, however the refrigerant inherently has higher GHG footprint.
Ključne besede: waste heat, waste heat utilization, aluminium industry, organic rankine cycle, power generation, optimization
Objavljeno v DKUM: 10.04.2025; Ogledov: 0; Prenosov: 1
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3. Public handling of protective masks from use to disposal and recycling options to new productsKatarina Remic, Alen Erjavec, Julija Volmajer Valh, Sonja Šterman, 2022, izvirni znanstveni članek Opis: A study was conducted on the waste of disposable surgical masks and their problematic impact on the environment. The studies examined have shown the negative effects on the environment that are likely to occur and those that have already occurred. In this article, society's relationship to the potential recycling of disposable surgical masks is considered and projected onto the possibilities of the cradle-to-cradle design approach. The development of a product from recycled surgical masks is driven by two different surveys. The first focuses on wear and disposal habits, and the second on the relationship to recycling. As a result, the flooring was developed with thermally treated recycled surgical masks replacing the filler layer. The goal of the product design was to improve the long-term life cycle analysis of a waste surgical mask.
Ključne besede: maske, medicinski odpadki, okolje, recikliranje izdelka z dodano vrednostjo, analiza življenjskega cikla, masks, medical waste, recycling added-value product, life-cycle-analysis
Objavljeno v DKUM: 26.03.2025; Ogledov: 0; Prenosov: 1
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4. When technology meets sustainability: microplastic removal from industrial wastewater, including impact analysis and life cycle assessmentJan Puhar, Michael Toni Sturm, Erika Myers, Dennis Schober, Anika Korzin, Annamaria Vujanović, Katrin Schuhen, 2025, izvirni znanstveni članek Opis: Microplastics (MPs) that are ubiquitous in aquatic environments and industrial wastewater streams have been identified as key hotspots of MP contamination. It is significantly more effective to remove MPs at these points before they enter municipal wastewater streams. This study is an environmental assessment of a novel pilot plant for the removal of MPs and the chemical oxygen demand (COD) from wastewater with a high MP contamination from a plastics manufacturer in Germany. MP removal is based on physical–chemical agglomeration–fixation by organosilanes. Formed agglomerates are separated using a belt filter. The COD is removed by an adsorption process. The resulting MP removal was 98.0 ± 1.1% by mass and 99.9987 ± 0.0007% by particle count, while the COD was reduced by 96 ± 2.7%. The system’s sustainability is evaluated using the Life Cycle Assessment methodology, evaluating system construction, operation, and end-of-life considerations. The current pilot plant is also compared to an optimized circular and sustainable upgrade, where drivers of environmental burdens are eliminated and collected MPs are reused. Significant reductions in environmental impact categories are achieved and the global warming potential is reduced by 96%. This study provides a sustainability assessment of a novel technology and circular solution to remove MPs from highly polluted industrial wastewater.
Ključne besede: microplastics, life cycle assessment, impact analysis, removal technology, sustainable process design, carbon footprint, water quality, circular economy
Objavljeno v DKUM: 14.03.2025; Ogledov: 0; Prenosov: 4
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5. Synthesis of Rankine cycle systems with cascade and separate configurations utilising multiple heat sources at different temperature levelsMonika Dokl, Rok Gomilšek, Petar Varbanov, Yee Van Fan, Zdravko Kravanja, Lidija Čuček, 2023, izvirni znanstveni članek Ključne besede: multiple heat sources, Organic Rankine cycle, separate and cascade designs, Steam Rankine cycle, thermodynamic optimisation
Objavljeno v DKUM: 28.02.2025; Ogledov: 0; Prenosov: 2
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6. Life cycle assessment (LCA) of the impact on the environment of a cosmetic cream with gold nanoparticles and hydroxylated fullerene ingredientsRebeka Rudolf, Peter Majerič, Zorka Novak-Pintarič, Andrej Horvat, Damjan Krajnc, 2024, izvirni znanstveni članek Opis: This review provides a comprehensive Life Cycle Assessment (LCA) of a cosmetic cream to assess the environmental impacts throughout its entire life cycle, from raw material extraction to disposal, using the methodology according to international standards. The LCA was performed using the OpenLCA 2.0.1 software, with data from the Ecoinvent 3.8 database and relevant literature. The assessment focused on multiple impact categories, including climate change, acidification, eutrophication (freshwater, marine and terrestrial), ecotoxicity (freshwater), human toxicity (cancer and non-cancer), ionizing radiation, land use, ozone depletion, photochemical ozone formation, resource use (fossils, minerals and metals), and water use. The LCA of a cosmetic cream containing gold nanoparticles revealed significant environmental impacts across critical categories. The total climate change potential was 2596.95 kg CO2 eq., driven primarily by nanoparticle synthesis (60.7%) and electricity use (31.9%). Eutrophication of freshwater had the highest normalized result (3.000), with nanoparticle synthesis contributing heavily, indicating the need for improved wastewater treatment. The resource use (minerals and metals) scored 1.856, while the freshwater ecotoxicity reached 80,317.23 CTUe, both driven by the nanoparticle production. The human toxicity potentials were 1.39 × 10−6 CTUh (cancer) and 7.45 × 10−5 CTUh (non-cancer), linked to emissions from synthesis and energy use. The LCA of the cosmetic cream revealed several critical areas of environmental impact. The most significant impacts are associated with gold nanoparticle synthesis and electricity use. Addressing these impacts through optimized synthesis processes, improved energy efficiency, and alternative materials can enhance the product’s sustainability profile significantly.
Ključne besede: life cycle assessment, cosmetic cream, environmental impacts, gold nanoparticles
Objavljeno v DKUM: 17.12.2024; Ogledov: 0; Prenosov: 15
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7. The influence of the ratio of circumference to cross-sectional area of tensile bars on the fatigue life of additive manufactured AISI 316L steelLuka Ferlič, Filip Jerenec, Mario Šercer, Igor Drstvenšek, Nenad Gubeljak, 2024, izvirni znanstveni članek Opis: The static and dynamic loading capacities of components depend on the stress level to which the material is exposed. The fatigue behavior of materials manufactured using additive technology is accompanied by a pronounced scatter between the number of cycles at the same stress level, which is significantly greater than the scatter from a material with the same chemical composition, e.g., AISI 316L, but produced by rolling or forging. An important reason lies in the fact that fatigue cracks are initiated almost always below the material surface of the loaded specimen. Thus, in the article, assuming that a crack will always initiate below the surface, we analyzed the fatigue behavior of specimens with the same bearing cross section but with a different number of bearing rods. With a larger number of rods, the circumference around the supporting part of the rods was 1.73 times larger. Thus, experimental fatigue of specimens with different sizes showed that the dynamic loading capacity of components with a smaller number of bars is significantly greater and can be monitored by individual stress levels. Although there are no significant differences in loading capacity under static and low-cycle loading of materials manufactured with additive technologies, in high-cycle fatigue it has been shown that the ratio between the circumference and the loading cross section of tensile-loaded rods plays an important role in the lifetime. This finding is important for setting a strategy for manufacturing components with additive technologies. It shows that a better dynamic loading capacity can be obtained with a larger loading cross section.
Ključne besede: AISI 316L stainless steel, additive manufacturing, FEM, high-cycle fatigue, fractography analysis
Objavljeno v DKUM: 25.11.2024; Ogledov: 0; Prenosov: 16
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9. Stability analysis of the singular points and Hopf bifurcations of a tumor growth control modelDániel András Drexler, Ilona Nagy, Valery Romanovski, 2024, izvirni znanstveni članek Opis: We carry out qualitative analysis of a fourth-order tumor growth control model using ordinary differential equations. We show that the system has one positive equilibrium point, and its stability is independent of the feedback gain. Using a Lyapunov function method, we prove that there exist realistic parameter values for which the systems admit limit cycle oscillations due to a supercritical Hopf bifurcation. The time evolution of the state variables is also represented.
Ključne besede: bifurcation, cancer therapy, limit cycle, singular point, tumor therapy, tumor control
Objavljeno v DKUM: 12.08.2024; Ogledov: 73; Prenosov: 7
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10. Advanced technologies in logistics engineering : automated storage systems with shuttles integrated with hoisted carriageTone Lerher, Primož Bencak, 2022, izvirni znanstveni članek Opis: This paper presents automated storage systems with shuttles integrated with hoisted carriage for successful application in intralogistics. The first part of the paper presents classic and advanced AVS/RS along with specific intralogistics automation systems known as AutoStore from Swisslog and Skypod from Exotec. The second part of the paper focuses on an advanced system with shuttle vehicles capable of serving multiple tiers of the storage rack. An analytical model for the shuttle vehicles capable of serving multiple tiers of the storage rack is presented, which is based on (i) the sequences of acceleration, constant velocity and deceleration, and (ii) randomised assignment policy. Based on the presented model, the expected Single Command (SC) and Dual Command (DC) travel (cycle) time as well as the throughput performance of the shuttle vehicles capable of serving several tiers of warehouse, could be calculated. A programme code in MATLAB has been presented for the computation of throughput performances of automated storage systems with shuttles integrated with hoisted carriage capable of serving several tiers of the storage rack.
Ključne besede: analytical and numerical model, automated vehicle-storage and retrieval systems AVS/RS, automated warehouses, cycle time and throughput performance, shuttles integrated with hoisted carriage
Objavljeno v DKUM: 26.06.2024; Ogledov: 162; Prenosov: 19
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