Search Results (10,518)

Circular economy principles are increasingly influencing tourism development strategies, particularly in rural destinations characterized by strong linkages between agriculture, gastronomy, and local economic systems. This study develops and empirically examines a conceptual model investigating the relationship between circular economy practices, gastronomy integration, perceived authenticity, and destination competitiveness within rural tourism economies. The research focuses on the role of gastronomy as a circular tourism resource capable of connecting local sourcing, sustainability, and experiential value creation. Data were collected through a stakeholder-based survey targeting tourism enterprises, local producers, destination management organizations, and hospitality providers operating in rural tourism destinations. The proposed relationships were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM) implemented in SmartPLS 4 and bootstrapped mediation analysis. The findings indicate that circular economy practices positively influence gastronomy integration, while gastronomy integration significantly enhances perceived authenticity. Furthermore, authenticity demonstrates a strong positive effect on destination competitiveness. The mediation analysis confirms that gastronomy integration and perceived authenticity function as intermediary mechanisms through which circular economy practices contribute to competitiveness outcomes. The study contributes to tourism economics and destination competitiveness literature by developing and empirically testing a mediation-based framework linking circular gastronomy, authenticity, and rural tourism competitiveness. The findings provide theoretical and practical implications for destination managers and policymakers seeking to strengthen sustainability, local value creation, and competitiveness through circular gastronomy strategies. Full article

Steel dust is a waste generated during steelmaking in an electric arc furnace (EAF), which contains a high proportion of iron-bearing compounds, leading to the inclusion of this waste as a resource in the circular economy for steelmaking. In addition to the limitation related to granulation (the waste must be processed to obtain larger particle sizes), a limiting factor is the increasingly high Zn content due to the low-quality ferrous charge. For the recycling of steelmaking dust, preliminary processing is necessary to reduce zinc. The paper presents, in addition to qualitative characterization of steel dust, laboratory experiments on the compositional changes associated with zinc redistribution applying the hydrometallurgical leaching process in an alkaline environment, using sodium hydroxide (NaOH). The changes in the chemical composition were identified and evaluated using X-ray fluorescence (XRF) and energy-dispersive X-ray spectroscopy (EDX). The experiments consisted of treating steel dust samples with 5 M NaOH at 25, 70, 80 and 90 °C for 60 min, using solid-to-liquid ratios of 10, 15, and 25 g/L. The results indicate a reduction in ZnO content ranging from 4.52% to 16.82%, as determined from Na₂O-free normalization data. Room-temperature samples show only marginal changes in ZnO content. The XRF and EDX analyses indicate a moderate and condition-dependent redistribution of zinc in the solid phase after alkaline treatment, as evaluated using Na₂O-free normalized data. These values are derived exclusively from solid-phase measurements (XRF/EDX) and do not include zinc in the leachate; therefore, true zinc extraction efficiency cannot be determined. The research results attest to the viability and efficiency (as a solid-phase compositional transformation process) using NaOH as a leaching agent for the studied steel dust, thus providing a potential pathway for improved waste recycling in the steel industry. Full article

Interzeolite transformation (IZT) has emerged as a versatile strategy for accessing zeolite frameworks through controlled framework reorganization under comparatively simplified synthesis conditions. Unlike traditional synthesis approaches that frequently require organic structure-directing agents (OSDAs), highly alkaline media, and prolonged thermal treatment, IZT converts pre-existing zeolite into a new topology, enabling direct reuse of crystalline matter while reducing synthesis complexity. This review examines how structural drivers, including framework density, structural memory, and building-unit compatibility, govern transformation pathways and phase selectivity across five principal transformation approaches: (i) solution-mediated, (ii) assembly–disassembly–organization–reassembly (ADOR), (iii) mechanically assisted, (iv) steam-assisted, and (v) fully solid-state systems. These approaches promote distinct transformation pathways that govern framework reconstruction, structural inheritance, and phase selectivity. Recent advances in solvent-free, mechanochemical, steam-assisted, and microwave-assisted synthesis demonstrate the potential of IZT to reduce solvent consumption, template usage, and crystallization times. Despite these advances, major challenges remain in predicting transformation outcomes, controlling transient intermediates, and establishing scalable and quantitatively validated sustainability metrics. Collectively, these developments position IZT as a promising platform for the rational and sustainable design of next-generation zeolitic materials. Full article

A novel sodium-oxide-fluxed slag is applied in the aluminothermic reduction of manganese ore. The slag’s high Al₂O₃ solubility facilitates the recycling of Al₂O₃ through hydrometallurgical processes, where NaAlO₂ serves as a water-leachable compound. Aluminothermic reduction is gaining renewed interest as an alternative processing route for the circular economy. In addition, CO₂ emissions in aluminium production via the electrochemical Hall–Héroult process can be reduced if the process electricity is sourced from non-fossil fuels. The unique Na₂O-fluxed MnO₂ ore formulation includes a small quantity of carbon reductant to ensure rapid pre-reduction to MnO. This approach negates the need for a pre-roasting step. Feed mixture variations with different collector metal additions (Si, Cr, Cu) were made to improve alloy–slag separation efficiency. The collector metals may influence the chemistry of the slag. This work compares the phase chemistry of slags formed during aluminothermic reduction to equilibrium phase chemistries calculated for the Na₂O-SiO₂-Al₂O₃-MnO-CaO system. The slag phase morphology consists of distinct alumina-rich strands (1.5% to 2.1%) embedded within a Na₂O-SiO₂-Al₂O₃-MnO-CaO glass matrix. The alumina-rich strands appear molten, indicating that the processing temperatures were higher than their liquidus temperatures (1537 °C to 1655 °C), as high as 1921 °C and 2053 °C. These findings contribute to sustainable practices in the circular economy through the production of low-carbon ferro-manganese complex alloys. Full article

Agri-food by-products (BP) and BP-derived fractions are increasingly recognized as sources of functional and nutritional compounds (e.g., dietary fibers, proteins, waxes, phytosterols, phenolics, carotenoids) that can be upcycled into high-value food ingredients, to improve the sustainability of agri-food chains. This review provides a wide-ranging vision of the potential use of BP and BP-derived fractions in OG formulations, emphasizing the roles they can play (e.g., structuring agents, stabilizers, surfactants, physical scaffolds, fillers, sources of antioxidants), while offering mechanistic insights and science-based perspectives to support the rational design of tailor-made OGs for specific food applications. Particular attention is given to emerging areas including plant-based and hybrid products, and the valorization of insect BP and co-products. Finally, key gaps limiting BP-based OG design and application (e.g., effects on crystallization, interfacial phenomena, dispersion, scaffold/filler behavior, etc.) are identified and translated into a research roadmap and design guidelines for the formulation of tailor-made, scalable BP-based OGs. Full article

The mining industry faces increasing challenges related to the growing volume of tailings generated during mineral processing. This study presents a case study of the Complex Mine Waste Reduction (CMWR) concept implemented at the Polkowice Concentrator operated by KGHM Polska Miedź S.A. The approach integrates coarse ore sorting with tailings reprocessing for construction material production. Sorting improves flotation feed quality by rejecting low-grade gangue, while reprocessing converts fine tailings into value-added products. The combined implementation reduces tailing deposition by up to 22% and improves the operational copper recovery in flotation while maintaining overall process recovery at an essentially unchanged level. The results demonstrate the potential of integrated solutions for sustainable and circular mining. Full article

Waste-to-energy (WtE) systems are frequently proposed as complementary waste-management strategies; however, their climate performance depends on the interaction between thermodynamic efficiency, material circularity, and electricity-system characteristics. Existing life-cycle assessments generally provide static comparisons between landfill and WtE but rarely identify the operating conditions under which WtE remains environmentally competitive. To address this gap, a parametric life cycle–energy framework was developed by integrating attributional LCA with an analytical energy model capable of evaluating critical efficiency thresholds under varying recovery rates and electricity-grid conditions. Four representative thermoplastics (PET, HDPE, PP, and LDPE) were evaluated using ReCiPe 2016 Midpoint (H) in SimaPro under Mexican electricity conditions ($E{F}_{\mathrm{grid}}=0.444$ kg CO₂eq/kWh). Results indicate that total life-cycle climate impacts are dominated by upstream polymer production, whereas end-of-life management contributes only marginally to overall GWP. Critical-efficiency analysis revealed strong sensitivity to both recovery rate and electricity-grid carbon intensity. For PET, the minimum efficiency required for WtE to outperform landfill increased from 13.1% to 73.5% across the evaluated scenarios, whereas HDPE remained competitive at efficiencies below 1.3%. Monte Carlo simulations (10,000 realizations) further demonstrated that avoided emissions decline systematically with increasing recovery rates, with LDPE exhibiting the highest mean avoided emissions (1735 kg CO₂eq) and PET the lowest (811 kg CO₂eq). These results demonstrate that WtE climate performance is governed primarily by residual waste availability and electricity-system evolution rather than thermodynamic efficiency alone. Consequently, WtE should be interpreted as a transitional residual-waste management strategy whose long-term climate relevance decreases as material circularity and electricity-grid decarbonization advance. Full article

This preliminary study characterises type I collagen in the digestive system of the greater weever (Trachinus draco L.) by integrating histochemical and biochemical techniques. To the best of our knowledge, this study represents the first baseline mapping of type I collagen within the gastrointestinal tract of this species. Mallory staining and indirect immunofluorescence confirmed collagen presence across the oesophagus, stomach, and intestine. The histochemical quantification of the fluorescent area (100 measurements per organ across 15 fish specimens) showed no significant differences (p = 0.1315), indicating a uniform spatial distribution. However, biochemical analysis via hydroxyproline assay and a two-way ANOVA revealed significant differences in collagen content among organs (p = 0.0308). The stomach yielded the highest concentration (4.199 µg/mg), significantly exceeding that of the intestine (1.713 µg/mg; Šídák’s post hoc, p = 0.0300). This discrepancy suggests that the higher gastric content is due to greater fibre density rather than distribution area. SDS-PAGE and Western blot confirmed protein molecular weights of 100–130 kDa, corresponding to α1 and α2 chains typical of type I collagen. The combination of these histochemical and biochemical methods effectively detects and characterises collagen in fish gastrointestinal by-products. By introducing T. draco as a novel subject in this context, these findings provide essential baseline anatomical and histological data and offer a clear scientific justification for the biotechnological valorisation of unutilised commercial fishing by-products, fully aligning with sustainable marine circular economy principles. Full article

The valorization of culinary by-products into functional bioactive resources represents a significant advancement in sustainable biotechnology. This study characterizes an extract derived from “battuto toscano” by-products, a traditional blend of garlic, onion, carrot, and celery trimmings, recovered through circular economy principles. Comprehensive antioxidant profiling was performed alongside biological evaluations on human cell lines and anti-glycation assays. Results from Folin–Ciocalteu, FRAP, and TEAC assays confirmed a high concentration of secondary metabolites with significant scavenging capacity. In vitro testing on primary human fibroblasts and HaCaT keratinocytes revealed a concentration- and time-dependent biological response, with lower concentrations showing better compatibility and transiently enhancing HaCaT metabolic activity. Furthermore, BTE reduced AGE-associated fluorescence in the BSA–glucose model, particularly at 5 mg/mL, supporting its potential anti-glycation activity. These findings establish “battuto toscano” by-products as a reservoir of sustainable biomolecules. This study offers a transformative resource for the pharma/nutraceutical sectors by bridging culinary tradition with biomedical innovation. Full article

The transition toward a circular economy is accelerating the development of high-performance, sustainable polymeric materials derived from renewable resources. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) represent a versatile class of biodegradable polyesters with inherent flexibility and tunable side-chain chemistry, making them attractive candidates for advanced polymer applications. Here, we report a novel class of bio-based polyurethanes (PUs) incorporating mcl-PHAs as soft segments, marking their first application in polyurethane synthesis and shifting towards greener PU synthesis. Polyurethane networks were prepared using castor oil (CO) and mcl-PHAs as polyols, with hexamethylene diisocyanate (HMDI) as a hard segment. Material properties were systematically tuned by varying the mcl-PHA/CO ratio (100/0 to 0/100), enabling precise control over structure–property relationships. Comprehensive characterization confirmed urethane bond formation and revealed predominantly amorphous materials with tunable thermal and mechanical behavior. Increasing mcl-PHA content enhanced elasticity and influenced phase organization, underscoring its role as a flexible, bio-derived soft segment. The resulting materials exhibited competitive mechanical performance alongside adjustable swelling behavior and morphology. Importantly, in vitro biocompatibility (MRC-5 fibroblasts) and eco-toxicological evaluation (Caenorhabditis elegans) confirmed the absence of toxicity. These findings highlight the potential of mcl-PHAs as sustainable building blocks for advanced polyurethane systems. Full article

The transition to a circular economy requires the safe management of sewage sludge through nutrient and energy recovery. However, pharmaceuticals and personal care products (PPCPs) present a significant challenge. These compounds tend to accumulate in sludge via sorption, shifting the environmental burden from the aqueous phase to the sludge. This manuscript provides a comprehensive review of the scientific literature on technical alternatives for valorizing sewage sludge and removing emerging contaminants. The study evaluates the limitations of conventional biological methods, such as anaerobic digestion and composting, which exhibit variable efficacy and are often insufficient to degrade some commonly used pharmaceuticals. On the contrary, thermal treatments (pyrolysis, gasification, and hydrothermal processes) are considered robust alternatives capable of achieving the high removal of chemical compounds. Furthermore, the article emphasizes the innovative potential of utilizing carbon-based byproducts (biochar and hydrochar) as adsorbents, catalysts, or soil amendment to enhance the removal of PPCPs within the treatment infrastructure itself. The integration of advanced thermal technologies is essential to mitigate the risks of contaminant transfer to the food chain and ensure a safe and sustainable nutrient cycle. Full article

The construction sector contributes substantially to global greenhouse gas emissions, making material substitutions a key strategy for advancing sustainability transitions. Mass timber has emerged as a low-carbon alternative to mineral-based construction materials, offering biogenic carbon storage and compatibility with prefabricated and industrialized building systems. This study aims to systematically synthesize the economic, cost, and market evidence on mass timber construction by reviewing 143 peer-reviewed publications, with the objective of clarifying what is empirically known and where uncertainties remain. The reviewed literature reveals three core findings. First, economic outcomes are mixed: while several studies report regional value creation, supply-chain upgrading, and alignment with circular-economy principles, others highlight persistent constraints such as limited manufacturing capacity and uneven policy support. Second, construction cost findings vary substantially, ranging from cost parity or modest savings relative to conventional systems to premiums of approximately 10–15%, shaped by regional pricing, labor availability, transportation distance, regulatory conditions, and supply-chain maturity. Third, market-oriented studies consistently identify slow diffusion, limited practitioner experience, and risk-averse investment environments as key barriers to adoption. Overall, the review shows that economic performance is not yet consistently established and underscores the need for more standardized, context-sensitive, and methodologically consistent evaluation frameworks to support informed decision-making and the sustainable scaling of mass timber construction. Full article

The transition toward circular economy practices and CO₂ reduction goals is driving the development of new sound absorption technologies. Traditional absorbers made from mineral wool or foams provide broadband absorption; however, their production is associated with intensive energy consumption and non-renewable resources. This is why the focus has been shifting from the mere substitution of materials to integrated solutions that combine sustainability with structure. This paper reviews recent innovations in sustainable absorbers based on bio-based and recycled materials. The acoustic performance of porous materials depends on such factors such as pore structure, airflow resistivity and geometric parameters such as thickness, multi-layer structure and resonances. At the same time, additive manufacturing (AM) allows creating geometry-controlled absorbers providing advanced acoustic properties. Despite many sustainable absorbers demonstrating sufficient sound absorption properties at medium and high frequencies, their use at low frequencies remains challenging. Additionally, concerns regarding durability, flame retardance, and environmental consistency continue to limit their broader application. Yet, hybrid, multi-material strategies, particularly those combining geopolymer matrices with bio-based or recycled fillers, are identified as a promising route to address these limitations. This review outlines current trends and highlights key challenges and future directions in the design of sustainable sound-absorbing systems. Full article

Reliable battery health assessment is essential to accelerate battery electric vehicle (BEV) adoption, yet most existing in-vehicle methods do not capture the complex processes driving ageing. Electrochemical impedance spectroscopy (EIS) offers deeper diagnostic insight but faces significant architectural and integration constraints. This study establishes a rigorous system-level framework for practicable onboard EIS implementation, focusing on the integration within Battery Management System (BMS) and powertrain architectures. Various integration topologies for cell-, module- and pack-level EIS are evaluated, highlighting their key trade-offs. The viability of the presented architectures is assessed through an application-specific Multi-Criteria Decision Analysis (MCDA) for mass-market, high-performance and circular economy use-cases. This study confirms the feasibility of onboard EIS while providing industry and scientific stakeholders with practical guidance to advance battery diagnostics for next-generation BEVs. Full article

This study develops and validates risk-based emergency response scenarios for Biosafety Level 2 (BSL-2) and Animal Biosafety Level 2 (ABSL-2) facilities. Utilizing Bow-tie analysis, three multidimensional scenarios were constructed: infrastructure failure, biosecurity breach, and compound disaster. Four domain experts independently evaluated the scripts using the Content Validity Index (CVI), with an absolute consensus threshold of I-CVI = 1.00. To address operational gaps identified during initial evaluations, the revised protocols were strictly aligned with the Taiwan Centers for Disease Control (CDC) mandatory reporting thresholds for high-hazard incidents. Furthermore, the scripts explicitly defined the Incident Command System (ICS) to prevent communication fragmentation and integrated the NC3Rs tunnel handling technique to minimize occupational bite risks. Following these targeted refinements, all items achieved absolute expert consensus. This research translates static biosafety regulations into dynamic, stress-tested training tools. By providing a standardized instrument for resilience assessment, this study equips frontline personnel with the critical capacity to navigate cascading crises while strictly adhering to a “life safety first” paradigm. Full article