Search Results (2,211)

Peatlands cover approximately 3% of the global land area but store about 44% of the world’s soil carbon, making them a major carbon sink. Indonesia alone accounts for about 37% of global tropical peat carbon stocks. However, large-scale carbon emissions caused by fires and drainage during past economic development have transformed peatlands from carbon sinks into carbon sources. In response, restoration efforts have been implemented at both international and national levels. Tropical peatland restoration typically includes rewetting, revegetation, and community-based approaches, highlighting the need for quantitative assessments of carbon storage under different restoration strategies. This study focuses on the Perigi peatland in South Sumatra, Indonesia. We conducted field surveys of vegetation and soils to estimate carbon stocks per unit area and developed time-series land cover maps using satellite imagery. Based on these data, we assessed potential carbon storage under different restoration intensity scenarios. The results show that carbon stocks in the Perigi peatland are lower than the Indonesian average. However, under a full restoration scenario, up to 950,259 tC of additional carbon storage is possible, indicating high restoration potential. In contrast, without restoration, further carbon emissions are likely, underscoring the necessity of restoration efforts. Effective restoration requires a phased strategy from vegetation recovery to peat layer recovery, combined with socioeconomic approaches that consider local livelihoods, enabling degraded tropical peatlands to function as effective carbon mitigation systems. Full article

This study presents a comprehensive assessment of high-temperature performance, economic viability, and environmental sustainability of alkali-activated slag paste (AASB) incorporating municipal solid waste incineration bottom ash (MSWI-BA). The research systematically evaluates the effects of MSWI-BA content (0–12%), alkali content (2–6% Na₂O equivalent), water glass modulus (Ms = 0.75–1.75), and activator type on key performance metrics, both resource recovery and carbon reduction goals. Results show that the optimized formulation (6% MSWI-BA, 4% Na₂O, Ms = 1.5) achieves superior high-temperature resilience, retaining 76% of its initial compressive strength after 800 °C exposure—a stark contrast to OPC, which undergoes near-complete strength loss. Economic analysis reveals that while MSWI-BA offers an 88% reduction in raw precursor cost, the optimized AASB incurs a modest 3.7% total material cost premium over OPC, which is offset by its long-term sustainability benefits. Furthermore, a life-cycle assessment demonstrates that AASB has a 66.95% lower carbon footprint than OPC. Full article

Despite the rapid expansion of photovoltaic (PV) installations over the past decade, challenges such as curtailments of renewable energy sources (RESs) and grid constraints continue to limit the capacity of Cyprus’ power system to accommodate higher solar penetration. In this context, grid reliability, defined as the ability to maintain stable operation by balancing supply and demand, minimizing curtailment, and reducing stress on the island network, has emerged as a critical concern. The deployment of PV-plus-storage systems offers a viable solution to enhance grid reliability while alleviating operational constraints. This paper presents a real-world case study of the first commercially deployed grid-connected PV-powered, battery-integrated electric vehicle (EV) charging station in Cyprus. Commissioned in May 2025, the system integrates a 60.32 kW_p rooftop PV array, a 100 kW/97 kWh battery energy storage system (BESS), and a 160 kW DC fast charger. A custom cloud-based energy management platform enables real-time monitoring, forecasting, and optimization under a zero-export scheme. High-resolution operational and weather data were collected between 15 May and 30 November 2025. Over this period, the integrated PV-battery system supplied 29% of the site’s total energy demand (self-sufficiency rate of 28.97%) and achieved a self-consumption rate of 98.69%. Such rates would not have been attainable with a pure PV system, given the depot’s evening-concentrated EV charging demand profile, which requires the BESS to time-shift daytime solar generation. The system reduced depot electricity costs by approximately 29%, generating €16,010 in savings and avoiding 26.47 tonnes of carbon dioxide (CO₂) emissions compared to a grid-only baseline. Beyond site-level performance, the system contributed to grid stress reduction by absorbing excess PV generation that would otherwise have been curtailed/wasted. Operational insights indicate minimal temperature-related issues, highlight the importance of automated fault detection and alerting to minimize downtime, and demonstrate how periodic operation strategies can optimize system performance and mitigate curtailment in Cyprus’s isolated grid. Full article

This study investigates the optimal service life of urban Electric Multiple Units (EMUs) by integrating two complementary evaluation methods: economic service life and maintenance limit life. Using a comprehensive dataset from Seoul Metro—including 498 trainsets and 3554 overhaul records—this research examines the relationship between long-term maintenance costs, depreciation, and residual values. The economic service life is derived by minimizing the average equivalent annual cost (AEC), while maintenance limit life is assessed based on government guidelines that define cost-inefficiency thresholds. The analysis finds that the average economic service life for EMUs on Lines 1–4 is approximately 39 years—substantially exceeding the traditional 25-year benchmark used in past replacement policies. Maintenance limit life, based on permissible cost ratio thresholds, extends up to 47 years in some cases. Sensitivity analysis indicates that maintenance cost variations exert a greater influence on optimal service life than discount rate assumptions, highlighting the importance of strategic maintenance management. The proposed dual-framework approach demonstrates the limitations of rigid, statutory-based replacement planning and supports a transition toward data-driven, line-specific decision-making. The findings provide actionable insights for transit authorities and policymakers seeking to improve capital investment efficiency and optimize lifecycle management of urban rail assets. Beyond economic efficiency, the study contributes to sustainability by supporting resource-efficient asset utilization, reducing premature disposal of serviceable rolling stock, and lowering lifecycle carbon emissions associated with manufacturing new vehicles. The proposed framework thus offers a practical basis for integrating economic and environmental considerations in sustainable urban rail asset management. Full article

Over the past two decades, extreme climate and weather events have become increasingly frequent in the United States, and the carbon–water cycle of corn ecosystems has shown high sensitivity to climate change. However, traditional simulation methods that rely on coarse-scale reanalysis data are unable to reflect changes in local water and heat conditions accurately. This study combines in situ meteorological observations with remote sensing, using a long short-term memory model to simulate the daily gross primary productivity (GPP) and evapotranspiration (ET) of 684 corn-growing meteorological stations in the United States. In summer, GPP and ET showed a spatial pattern of gradual decrease from the humid eastern region to the arid western region, and the multi-year daily averages at meteorological stations showed a single-peak pattern. The sensitivity of GPP and ET changes is mainly influenced by leaf area index (LAI) and shortwave radiation downward changes, which together explain more than 90% of the main variation in GPP and ET at the meteorological stations. The 2012 drought caused a general decline in GPP and ET, with the peak occurring approximately 15 days earlier than usual. Water use efficiency (GPP/ET) decreased at 85% of the sites (p < 0.05), but photosynthesis per unit leaf area (GPP/LAI) increased at 63% of the sites (p < 0.05). This study demonstrates the importance of meteorological station-scale data for understanding carbon–water flux dynamics in cornfields. Integrating the models developed in this study with medium-to-long-term climate projections will further guide climate-informed agricultural water management and provide reliable accounting and pricing tools for agricultural land carbon markets and carbon trading. Full article

Efforts to improve the energy performance of historic buildings have attracted growing attention from both policymakers and researchers over the past few decades. Based on 318 publications from the Web of Science database, this study conducts a review analysis in the field of historic building energy retrofit. Bibliometric analysis shows a remarkably increasing trend in research on this topic since 2015 and reveals a research imbalance between developed regions (e.g., Europe) and developing regions. This review examines the retrofit approaches of historic buildings using both passive and active strategies and synthesizes the understanding of life cycle assessment carbon emissions across different systaem boundaries, emission stages, and carbon accounting approaches. The results show that previous studies tend to focus primarily on energy performance, yet predominantly rely on simulation studies of individual cases, limiting cross-regional comparisons and the broader transferability of findings. Therefore, a multi-objective evaluation framework is proposed, considering thermal comfort, energy use, and carbon emissions, enabling identification of suitable retrofit measures across different contexts. By examining the problems and strategies in this field, this study highlights the substantial potential of historic building energy retrofit and provides a basis for future evaluation and decision-making. Full article

Soil Organic Matter (SOM) and Soil Organic Carbon (SOC) are essential for regulating ecosystem functions, soil fertility, and influencing climate change processes, especially in semi-arid regions. The recent improvements in remote sensing instruments and the development of artificial intelligence methodologies, such as machine learning, enable an improved understanding of carbon dynamics, facilitate the estimation of SOC content, and support predictive modeling. This study presents an integrated framework to analyze past and future carbon dynamics in the Sfax Governorate (Tunisia). Land-use and land-cover (LULC) maps for the years 2019, 2020, 2022, and 2024 were generated using a Random Forest algorithm applied to multispectral satellite data in the Google Earth Engine platform, achieving high classification accuracy (overall accuracy up to 0.90). Carbon stocks and their temporal variations were estimated using the InVEST Carbon Storage and Sequestration model, while carbon emissions and the Net Ecosystem Carbon Balance (NECB) were derived by integrating land-use-specific emission factors. Future LULC scenarios for 2030 were simulated through a Cellular Automata model under three alternative development pathways: conservation-oriented (CONS), business-as-usual (BAU), and urban expansion (URB+). The study demonstrates how the integration of machine learning, remote sensing, and ecosystem modeling supports spatially explicit assessment of SOC-related carbon dynamics and provides useful insights for land management and climate mitigation strategies. Full article

Aromatic compounds derived from the shikimate (SHK) pathway constitute a diverse class of high-value molecules with applications in the pharmaceutical, food, cosmetic, and chemical industries. In microbial systems, particularly Escherichia coli, this pathway links central carbon metabolism (CCM) to the biosynthesis of L-tyrosine (L-Tyr), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp), which serve as key precursors for structurally diverse metabolites. Over the past decades, metabolic engineering strategies have focused on increasing precursor availability, relieving feedback inhibition, and eliminating competing pathways. More recently, advances in synthetic biology have enabled dynamic control of metabolic flux through pathway modularization, genome-scale interventions, and regulatory circuit design. In this review, we provide a comprehensive overview of the engineering of E. coli for aromatic compound biosynthesis, highlighting key developments in the optimization of the SHK pathway and its major metabolic nodes chorismate, L-Tyr, L-Phe, and L-Trp. We examine emerging approaches, including CRISPR-based regulation, biosensor-driven dynamic control, membrane engineering, and synthetic microbial consortia. Despite significant progress, challenges related to pathway regulation, cofactor balance, metabolic burden, and product toxicity remain critical bottlenecks. Integrating metabolic engineering with synthetic biology is driving the development of programmable, scalable microbial platforms for the efficient bioproduction of aromatic compounds. Full article

Under the guidance of the “dual carbon” goals, building energy efficiency policies are currently in a critical phase of transitioning from “dual controls on energy consumption” to “dual controls on carbon emissions.” Based on the theory of policy instruments, this paper takes 26 building energy efficiency policy documents issued in Tianjin from 1991 to 2025 as samples. By comprehensively applying content analysis and social network analysis, it systematically examines the evolutionary trajectory, combination characteristics, and structural relationships of policy instruments over the past three decades. This study reveals that Tianjin’s building energy efficiency policy system demonstrates a phased transformation trend—shifting from singular control to diversified incentives and from energy consumption constraints to integrated carbon emission management. The structure of policy instrument combinations has been progressively optimized; however, there remains room for improvement in terms of policy synergy, continuity, and the role of market mechanisms. Consequently, this paper proposes recommendations for optimizing local building energy efficiency policies across dimensions such as instrument coordination, temporal allocation, and mechanism innovation. These suggestions aim to enhance policy implementation effectiveness, accelerate the transition towards energy conservation and carbon reduction in the building sector, and provide empirical references for similar cities seeking to optimize their “dual carbon” policy frameworks. Full article

Silicomanganese slag (SiMnS), a Mn-bearing by-product from silicomanganese alloy production, is often stockpiled in large quantities and may pose environmental concerns due to potential metal leaching. This study develops an OPC-rich hybrid SiMnS–steel slag–fly ash–OPC-activated composite binder, referred to as SMSAB, in which OPC accounts for 55% of the solid precursor mass. Different alkali contents and sodium silicate moduli were investigated, and the optimised paste was characterised in terms of mechanical strength, reaction products, pore structure, carbon-footprint and heavy-metal leaching. The best performance was obtained at an alkali content of 4% and a sodium silicate modulus of 1.0, giving 28-day compressive and flexural strengths of 65.13 MPa and 3.37 MPa, respectively. XRD, SEM-EDS, FTIR and MIP results showed that the main reaction products were C-(A)-S-H, N-A-S-H and C-N-A-S-H gels, which refined the pore structure and produced a dense matrix. The reduction in Mn leaching may be associated with physical encapsulation, possible charge-balancing interactions within gel structures, changes in Mn-related bonding environments and the presence of Mn-bearing phases. Leaching concentrations of Zn, Mn, Cr, Cu and Ni satisfied the Grade III groundwater limits used in China. The calculated carbon intensity of SMSAB was 3.97 kg·(m³·MPa)⁻¹, indicating a favourable strength-to-emission balance compared with the reference systems considered. It should be noted that the present work examines paste specimens only; aggregate skeleton, traffic loading, freeze–thaw cycling and wet–dry/moisture cycling were not included. Therefore, the results demonstrate binder-level potential rather than direct qualification of SMSAB as a pavement base or subbase material. Full article

As a member state of the European Union, Bulgaria is committed to decarbonisation and the achievement of sustainable development goals. The country has a well-established energy sector and is a net exporter of electricity produced from diverse sources. Electricity generation relies mainly on two key pillars: lignite-fired Thermal Power Plants (TPPs) and the Nuclear Power Plant (NPP) in Kozloduy. This study examines the status of Bulgarian state-owned energy companies (SOEC) and their capacity to respond to the challenges of a sustainable transition towards low- or zero-emission electricity production. The study contributes to the existing literature by providing insights from a comparative analysis of state-owned thermal and nuclear power generation in Bulgaria, examined through the lens of sustainable development. From a practical standpoint it contributes by outlining possible pathways for the sustainable transformation of carbon-intensive TPPs. The analy-sis is based on key sustainability indicators covering the three pillars of sustainable development—economic, social and environmental performance. It includes not only an assessment of the financial performance of state-owned thermal power plants and the nuclear power plant over the past five years but also selected social and environmental indicators. The findings suggest that nuclear energy production in Bulgaria is largely consistent with the core principles of sustainability, while coal-based thermal power plants face increasing economic pressures and contribute to significant environmental impacts. The results highlight the need to transform the coal-based electricity sector into a more economically viable and socially responsible alternative, such as low-carbon generation technologies including nuclear energy. Full article

The city of Veracruz preserves buildings mainly constructed during the 16th and 17th centuries, where carved madreporic coral was used as ashlar and as a component in mortars. These historic structures, now part of Mexico’s built heritage, show various degrees of deterioration caused by erosion and prolonged exposure to environmental elements. Restoration using original materials is currently nearly impossible due to ecological restrictions protecting coral reefs. In this context, and under the principles of the tailor-made technique, the present research revisits physico-mechanical and chemical studies conducted on the corals used in the construction of one of the most representative buildings in the city. The results were compared with those obtained from the formulation of experimental mortars using readily available materials—such as air lime, siliceous aggregates, and calcium carbonate—with the aim of reproducing the physical, mechanical, and chemical properties observed in the original corals. Laboratory tests allowed evaluation of their compatibility and performance, seeking to develop alternative materials that enable conservation interventions without compromising the integrity of the base material or the historic structures. The design of mortars is intended to be used in the restoration processes of buildings that are part of the built historical heritage. This is the starting point for understanding the characteristics of the mortar and its compatibility with the substrate, which could be used for repairing stone blocks and for preparing new mortars for masonry and plastering, since research on restoration mortars has largely overlooked this type of building with coral masonry due to its rarity. Therefore, this research is of particular interest. The mixtures formulated with calcareous sand were the most compatible with the reference coral material, while those made with silica sand exhibited properties superior to the corals, and marine sands showed very poor behavior, potentially compromising the integrity of the buildings. In physical–mechanical tests, formulations that include calcareous sand and silica sand (2 mm) demonstrated behavior closest to that of coral, consistent with chemical analysis results, where mortars formulated with calcareous sand registered the highest contents of CaO and portlandite. Mercury intrusion porosimetry indicated that the mortar formulated with silica sand (2 mm) has a porosity only 4.07% lower than that of the coral, while mortars formulated with calcareous sand and lime paste are between 11.17% and 16.87% lower. Therefore, one of the mixtures that stands out as the best option due to its similarity in physical–mechanical and chemical results is the composite that is not found at the extremes of the results obtained in the various tests carried out. The use of calcareous sand, as previously mentioned, enhances its behavior and affinity with the coral masonry, as demonstrated in the tests. Full article

Environmental targets towards net-zero carbon concrete are increasing the demand for eco-efficiency in concrete production. Promising measures to increase sustainability include the combination of high levels of limestone fillers (LFs) and the use of advanced mix-design techniques, such as particle packing models (PPMs). However, there is still a limited understanding of the fresh and hardened state properties of eco-efficient mixtures; the literature suggests that mobility parameters (MPs; interparticle separation distance—IPS; maximum paste thickness—MPT) can help explain the fresh behaviour of concrete mixtures. Yet, the impact of MP values on fresh properties is still not fully understood. To address this gap, this study evaluates a reduced-complexity system comprising twelve concrete mortar fractions developed with distinct MP ranges and high LF contents (up to 52%). The use of mortar mixtures was intended to reduce the number of variables in the system and provide a clearer assessment of the role of mobility parameters. Time-dependent rheological behaviour (flow behaviour factor, torque, and viscosity) is analyzed and correlated with MP ranges to identify governing fresh state mechanisms. In addition, the relationships of IPS and MPT with compressive strength and porosity are evaluated to examine their relevance to the hardened state behaviour of low-carbon mixtures with reduced cement content. Results indicate that MPT and IPS can be used as practical indicators of rheological behaviour, with MPT showing the strongest influence on rheological response across all mixtures. Based on compressive strength and porosity measurements, empirical models are proposed to describe the effect of mobility parameter-based spacing concepts on hardened properties. Finally, the environmental performance of the optimized mixtures is assessed, confirming the potential of LF-rich, MP-tailored mixtures to contribute to low-carbon, net-zero concrete production. Full article

As a major source of energy consumption and greenhouse gas emissions, the low-carbon retrofitting of existing buildings can help to alleviate climate pressures and increase environmental resilience, and it is an effective and feasible way to achieve the goal of sustainable development. However, the majority of existing urban renewal research focuses on analyzing influencing factors, carbon reduction potential, carbon reduction measures, and the cost-effectiveness of carbon reduction. There is a lack of systematic review and synthesis of theoretical and technological research in carbon reduction and retrofitting. Using the systematic literature review method following the PRISMA protocol, we screened 244 peer-reviewed articles at the title/abstract level and conducted an in-depth analysis of 77 studies that met the PICOS-based inclusion criteria. This review summarizes the evolution of low-carbon retrofit technologies for existing buildings over the past five decades, and identifies climate change pressures, policies and regulations, stakeholder demand, and technological innovation as the primary drivers for decarbonizing existing buildings. These drivers, which are also influenced by technological capabilities, retrofit markets, and inherent building characteristics, drive both building decarbonization and broader SDGs such as climate mitigation. Focusing on the drivers of decarbonization, technological development, and retrofit benefits in retrofitting existing buildings, this review presents an inventory-based technical pathway framework. We identified key issues in the decarbonization and retrofitting of buildings and developed this framework to guide decarbonization and retrofitting practices. The framework can provide tech-driven retrofit guidance for researchers, policymakers, and administrators. Full article

This study evaluates the potential of using Granulated Waste Tire Rubber (GWTR) as an alternative raw material in geopolymer mortars an eco-friendly, low-carbon alternative to traditional cement-based systems. The research investigates the synergistic effect of industrial by-products, such as slag (from ferrochrome plants) and fly ash (from thermal power plants), combined with varying proportions of GWTR (1/4, 1/3, and 1/2 by volume). A total of 22 mixtures were prepared using diverse binder pastes, including pure cement, slag-based, and fly ash-based geopolymer systems, alongside their cement-substituted derivatives. The mechanical and physical performances were assessed through compressive strength, flexural strength, and Ultrasonic Pulse Velocity (UPV) tests at 3, 7, 28, and 180 days, complemented by SEM microstructural analyses. The findings indicate that while GWTR significantly reduces the mechanical properties of pure cement matrices, this negative impact is substantially mitigated in geopolymer mortars supplemented with 5–10% cement. Mixtures containing 1/4 GWTR with 90–95% slag or fly ash (M6, M7, M15, M16) yielded the most successful results in terms of both strength and sustainability, specifically, mixtures M7 and M16 because the hybrid binder synergy effectively compensated for the rubber-induced porosity, ensuring a denser matrix and structural-grade compressive strength alongside high sustainability. Significant decreases in performance were observed at higher GWTR ratios, particularly at the 1/2 level. Overall, the study demonstrates that integrating GWTR into optimized geopolymer systems offers a viable pathway for the valorization of environmental waste and minimizing the ecological footprint of the construction industry. Full article