Assessing the impact of implementing circular economy strategies in the construction industry: A case study in the Ruhr Area in Germany.

A geometric analysis of the Bazykin-Berezovskaya predator-prey model with Allee effect in an economic framework

Waste-to-biohydrogen production technologies: Microbial pathways, omics insights, and techno-economic assessment for a circular hydrogen economy

Research on the coupling coordination and spatial influence effect of the digital economy and carbon emission

This study presents the long-term performance of a 3.3 kWp semi-transparent photovoltaic (STPV) system using five years (2017-2021) of operational data collected in Gödöllő, Hungary. A comprehensive 4E (energy, exergy, economic, and environmental) framework is applied to quantify system performance under real climatic conditions. The system generated an average yearly electricity production of 2490 kWh, with variability driven by irradiance and temperature fluctuations. Exergy analysis based on Petela model revealed average exergy efficiencies significantly lower than energy efficiency due to spectral mismatch and the partial transmittance inherent to the STPV design. Environmental assessment was conducted using updated life-cycle emission intensities (28-100 g CO 2 eq/kWh and 40-110 g CO 2 eq/kWh), resulting in an embodied carbon range between 1.74 and 6.85 tonnes CO 2 eq across the two literature scenarios. Under three grid emission scenarios (0.35, 0.25, and 0.15 kg CO 2 eq/kWh), carbon payback time (CPT) ranges from 2.0 to 18.3 years. Economic evaluation yielded a levelized cost of electricity (LCOE) ranging from €0.095 to €0.117 per kWh, with a simple payback period of 9.5-11.7 years. The results demonstrate that STPV systems can achieve carbon neutrality within their operational lifetime under grid conditions, although environmental performance remains sensitive to future decarbonisation pathways. The proposed framework provides reproducible methodology for evaluating STPV systems using long-term empirical datasets. • Five-year operational analysis of a 3.3 kWp semi-transparent PV system. • Comprehensive 4E framework applied: energy, exergy, economic, and environmental. • Average annual electricity generation reached 2490 kWh under real climate conditions. • LCOE ranges from €0.095–0.117 kWh with a payback period of 9.5–11.7 years. • Carbon payback time varies between 2.0 and 18.3 years depending on grid emissions. • Results confirm long-term viability of STPV systems for BIPV applications.

Research on waste electrical and electronic equipment (WEEE) management has persistent gaps in environmental, social, and economic aspects. This paper systematically analyzes emerging indicator information, contrasting implicit (less tangible) aspects, such as governance and socio-economic issues, with explicit (more tangible) aspects, including environmental and technical issues using the Multi-level Perspective (MLP) framework. This study aims to provide a comprehensive review of 62 articles related to e-waste in Malaysia, focusing exclusively on journal publications and proceedings from 2010 to 2024. This finding highlights a significant imbalance in e-waste research in Malaysia, based on an analysis of 62 selected articles. The study revealed that research on social aspects accounts for 72% of the total, while studies focusing on economic aspects represent only 3%. This oversight has resulted in ’regime resistance’ and has revealed weaknesses in the current policy framework. Furthermore, the findings indicate challenges in integrating informal actors and systems into the formal e-waste management framework for households, as evidenced by the alarmingly low reported recycling rate of just 1%. Finally, this paper suggests five key recommendations for achieving optimal e-waste management performance: (1) Linking local solutions with global strategies; (2) Developing a circular economy (CE) framework and extended producer responsibility (EPR) model; (3) Implementing basic design principles; (4) Enhancing governance and social awareness; and (5) Adopting a systems analysis approach.

Integration of agro wastes as an alternative substrate for microalgae cultivation: A review

Synergistic pretreatment for biorefinery of spent coffee grounds: Enhancing hemicellulose and methane yield with black liquor-catalyzed composting

• Elucidating the anaerobic digestion mechanisms for food-waste valorization • Evaluation of pre-treatments enhancing biodegradability and methane yield • Identification of key factors influencing digestion efficiency and stability • Discussion of challenges and future pathways for AD advancement The escalating global volume of food waste poses significant environmental challenges but also represents a substantial opportunity for sustainable energy generation. Anaerobic digestion (AD) is a leading technology that converts this waste into biogas, offering a dual solution for renewable energy production and waste management. This comprehensive review delves into the application of AD for food waste, providing an in-depth analysis of the underlying biochemical processes and critical operational parameters that govern biogas yield such as; temperature, pH, and organic loading rate. It further explores a range of physical, chemical, and biological pre-treatment methods to enhance the efficiency of waste breakdown. The review further investigates recent advancements, including innovative reactor designs, co-digestion strategies, and process optimization techniques, all aimed at improving system performance and scalability. While addressing key challenges like feedstock variability, process instability, and inhibition, the review proposes practical mitigation strategies. Finally, it evaluates the environmental and economic viability of AD, discussing its integral role in circular economy frameworks by transforming waste into valuable resources. This synthesis aims to guide future research and accelerate the adoption of anaerobic digestion as a cornerstone technology for sustainable waste-to-energy conversion.

Feasibility study of co-mixing biomass with additive waste materials for biochar high calorific value of co-firing applications

Grape canes as a multifunctional agricultural by-product: A comprehensive review from polyphenols to energy valorization in a circular economy framework

Blueberry pomace, the primary solid by-product of juice and wine processing, represents a significant resource inefficiency in the food industry. Despite containing high concentrations of anthocyanins, phenolic acids, flavonoids and dietary fibers, the majority of this biomass is currently discarded or used as low-value compost. This mini-review critically examines the technological pathways for transforming blueberry pomace from an environmental burden into high-value functional ingredients. It analyzes recent advances in green extraction technologies and evaluates the efficacy of incorporating pomace into functional foods, animal feed, active packaging systems and sustainable materials. Distinct from broader overviews, this review focuses specifically on the stability of bioactive components during processing and the technological feasibility of industrial upscaling. The article identifies key bottlenecks, including bioaccessibility limitations and sensory impact in fortified products, at the same time as proposing a circular economy framework to guide future product development. © 2026 Society of Chemical Industry.

ABSTRACT In the context of Donald Trump’s return to office and the escalating geopolitical rivalry between the U.S. and China, this study provides timely insights into how macro-level political and economic forces intersect with micro-level agency in shaping the decisions and lived experiences of Chinese international students. Drawing on the theoretical frameworks of geopolitical economy and student self-formation, this article critically examines how global power dynamics and structural constraints influence international students’ educational trajectories. Based on the semi-structured interviews with 38 Chinese students at a U.S. public research university, the study finds that their decisions to study abroad are shaped by concerns about personal safety, financial constraints, and restrictions on international mobility. However, these students are not merely passive recipients of these external challenges; they actively navigate these political and economic uncertainties by leveraging transnational social networks and digital resources, exploring alternative educational and career pathways, and adapting their aspirations in response to shifting global landscapes. By highlighting the entanglement of geopolitics, race, and higher education, this study calls for a geopolitical turn in higher education research to better theorize how international students are positioned not only through race and class, but also through nation-state rivalry and global restructuring.

This study investigates the effect of tomato and grape pomace powders on the structural and rheological properties of carrot-based mousses, with complementary physicochemical and compositional analyses. The incorporation of tomato pomace (TEP) resulted in increased viscosity, adhesiveness, and cohesiveness, accompanied by a brighter and more color-stable appearance. In contrast, grape pomace (GPP) enhanced hardness and contributed to a more compact internal structure, while producing darker and less saturated color tones. Both pomace powders significantly affected the microstructure and elemental composition of the mousses. The tomato pomace was associated with a higher relative abundance of potassium and magnesium, whereas the grape pomace increased the relative levels of nitrogen, phosphorus, calcium, and iron. Increasing pomace concentrations led to a decrease in pH, particularly in the TEP_3.0 and GPP_3.0 variants, indicating an acidifying effect of the added plant materials. The results demonstrate that fruit and vegetable pomace powders can effectively modulate the structural, rheological, and compositional characteristics of plant-based mousses. These by-products represent functional ingredients that support the valorization of food processing waste and offer technological potential for the formulation of fiber- and polyphenol-enriched semi-solid food products within a circular economy framework.

ABSTRACT Despite decades of substantial investment in electricity infrastructure, Angola faces a striking paradox: widespread electricity poverty coexists with significant overcapacity in power generation. By the end of its 2007–2025 development strategy, national electrification had increased only modestly – from 34 per cent to 42 per cent – despite rapid economic growth driven by oil revenues and heavy public investment in energy production. Today, Angola has an installed generation capacity of approximately 6.2 GW, of which only about two-thirds is utilised, while more than half of the population remains without access to electricity due to severe deficits in transmission and distribution infrastructure. This article investigates Angola’s electricity sector reform since the early 2000s, focusing on the construction of the Laúca and Caculo Cabaça hydropower dams as emblematic megaprojects. It asks whether Angola’s energy restructuring can be understood as a case of infrastructure failure and examines how international finance, domestic political settlements, and elite incentives shape infrastructure outcomes. Drawing on a global political economy framework, the paper argues that infrastructure failure in Angola emerges from the convergence of external financial constraints, fragmented principal–agent relations, and elite political incentives reinforced by high-modernist development ideologies.

Assisted by multidimensional data analysis, chemical recycling methods for waste generated by the renewable energy sector in the context of the circular economy.

The assembly of functional nanomaterials at liquid-liquid interfaces offers a promising approach to address mass transfer and catalyst-recovery limitations in conventional biphasic catalytic systems. This strategy exploits engineered colloidal particles serving dual roles as emulsion stabilizers and catalytic sites, creating platforms with high interfacial area-to-volume ratios. These systems can exhibit improved reaction kinetics with efficient phase separation and catalyst recyclability while potentially operating under milder conditions that reduce energy consumption and waste generation. This review analyzes recent developments in the design, synthesis, and surface engineering of interfacially active nanocatalysts. It is examined structure-performance relationships governing catalytic efficiency and emulsion stability, assess industrial implementation challenges including scalability and economic viability, and evaluate prospects of Pickering emulsion-based microreactor platforms as enabling technologies for sustainable chemical processes aligned with green chemistry principles and circular economy frameworks.

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a mechanical life support modality used in patients with severe respiratory failure. Despite rising case numbers worldwide, costs are substantial, while patient-centered outcomes, particularly survival and quality-adjusted life years (QALYs), remain uncertain. High complication and mortality rates also persist. Limited financial budgets, human resources, and treatment capacities in healthcare systems require critical evaluation of whether continued use of this resource-intensive intervention at the current scale is sustainable and ethically justifiable. This study aims to provide further insight into this issue and to support healthcare decision-making by offering a structured economic and ethical framework for evaluating VV-ECMO, particularly regarding resource allocation, proportionality of costs, and the justification of its use in high-cost intensive care. This mixed-methods study consists of two parts. Part A includes two systematic literature reviews. The first examines total and daily in-hospital costs per patient, as well as outcomes measured in QALYs for adult patients supported with VV-ECMO across multiple countries between 2005 and 2024. The second aim is to identify established interventions with confirmed QALY gain that can subsequently be used as comparators for VV-ECMO. Part B evaluates the results according to the principles of medical ethics: beneficence, non-maleficence, autonomy, and justice. Given limited financial, personnel, and treatment capacities in healthcare systems, the question of how highly resource-intensive interventions such as VV-ECMO can be justified has increasing clinical, economic, and ethical relevance. By linking cost-related outcomes with a structured ethical evaluation, this study aims to contribute to a more differentiated discussion of whether and under which conditions VV-ECMO may be considered proportionate and justifiable within resource-constrained healthcare settings. Expected challenges include data availability and quality, differences in reported charges versus costs, and variation in healthcare systems, reimbursement structures, and national decision-making frameworks. These factors represent inherent limitations of international comparisons. The analysis is therefore intended as a comparative and contextual assessment rather than a formal cost-effectiveness evaluation within a single national reimbursement framework, particularly as no officially established uniform willingness-to-pay threshold per QALY exists in Germany. Not applicable. This study does not involve interventional clinical research. The protocol was registered on the Open Science Framework ( https://osf.io/24ky5 ).

This paper explores the intersection of sustainable development and marine tourism through an in-depth analysis of the “Blue Flag” certification program as applied to marinas in the Attica region of Greece. The study investigates the environmental, social, and economic implications of Blue Flag-certified marinas, using a sample of five facilities that consistently meet international sustainability standards. Drawing on primary data collected through structured questionnaires and supported by secondary data from relevant institutional sources, the research assesses operational efficiency, compliance with environmental protocols, and the broader benefits of certification. Findings indicate that Blue Flag certification enhances marina prestige, visitor satisfaction, and environmental performance, though it has limited direct impact on revenue. The paper identifies key challenges such as energy consumption and berth shortages, while highlighting best practices in environmental management and safety. The study concludes with strategic recommendations to strengthen sustainable practices and enhance the competitive positioning of certified marinas within the Blue Economy framework.

Ensuring sustainable food production for a growing population requires robust tools like the Life Cycle Assessment (LCA), despite the fundamental complexities characterising the agri-food sector. This study evaluates the environmental impacts of beer and bread production, two important sectors, within a circular economy framework using the LCA. The analysis focuses on innovative products: bread incorporating brewery-spent grain and beer brewed from unsold bread. The study follows a cradle-to-gate approach, covering the entire upstream supply chain, including cultivation, milling, malting, and ingredient production. Cultivation emerges as the primary environmental hotspot in both systems. In bread production, the bakery and proofing phases also show high impacts, while in brewing, packaging is the dominant contributor, followed by boiling and hopping. For co-product processing, drying and transport are critical hotspots. Compared with conventional products, innovative circular products generally show lower environmental impacts, with exceptions related to organic cultivation and allocation constraints. Circular strategies notably reduce land use and marine eutrophication in most organic cases. Overall, the fully circular scenario outperforms the Conventional System in 13 impact categories, supporting the environmental potential of circular approaches in both sectors.