The increasing concentration of carbon dioxide (CO2) in the atmosphere is widely recognized as one of the main drivers of climate change [...]

Biomass pyrolysis has emerged as a flexible platform for converting low-value residues into higher-value energy carriers (bio-oil, biochar and gas) and carbon-rich materials, with realistic potential for negative emissions when biochar is deployed in long-lived sinks. Over the last decade, three developments have driven the field forward: first, a finer mechanistic understanding of devolatilization and secondary reactions; second, major improvements in analytical techniques for characterising feedstocks and products; and third, more rigorous techno-economic and life-cycle assessments that place pyrolysis in a broader energy-system context. Recent experimental work on forestry and agro-industrial residues has clarified how biomass composition, ash chemistry and operating conditions jointly govern product yields, energy content and stability. Parallel advances in GC×GC–MS, high-resolution mass spectrometry, NMR and thermogravimetric methods have shifted the discussion from bulk “bio-oil” and “char” to families of molecules and well-defined structural domains, which can be deliberately targeted by reactor and catalyst design. Data-driven models, ranging from support vector machines applied to TGA curves to ANFIS and random forests for yield prediction, are now accurate enough to support process screening and multi-objective optimisation. At the system level, commercial fast pyrolysis biorefineries report overall useful energy efficiencies on the order of 80–86%, while slow pyrolysis configurations centred on biochar can be economically viable when carbon storage and co-products are appropriately valued. Thermodynamic analyses confirm that indirect gasification via fast-pyrolysis oil sacrifices some energy and exergy efficiency relative to direct solid-biomass gasification but may offer logistical and integration advantages. This review synthesises recent work on (i) feedstock and process characterisation; (ii) state-of-the-art analytical methods for bio-oil, biochar and gas; (iii) modelling and machine-learning tools; and (iv) energy-system deployment of pyrolysis products. Throughout, the emphasis is on how characterisation and modelling inform concrete design choices and on the trade-offs that arise when pyrolysis is considered as part of a wider decarbonisation portfolio. By integrating laboratory-scale characterisation with system-level modelling, this review aligns biomass pyrolysis with several United Nations Sustainable Development Goals (SDGs). The optimisation of thermochemical conversion pathways for forestry and agro-industrial residues directly supports SDG 7 (Affordable and Clean Energy) by enhancing the efficiency of bio-oil and syngas production. Furthermore, the deployment of biochar as a stable carbon sink for negative emissions and soil amendment addresses SDG 13 (Climate Action) and SDG 15 (Life on Land). By converting low-value waste streams into high-value energy carriers and chemicals within a circular bioeconomy framework, the research further contributes to SDG 12 (Responsible Consumption and Production) and SDG 9 (Industry, Innovation and Infrastructure).

Biodegradable poly(lactide)/poly(ε-caprolactone) (PLA/PCL) systems functionalized with TiO2–SiO2 were synthesized via in situ ring-opening polymerization of a eutectic L-lactide/ε-caprolactone system. This work introduces a TiO2–SiO2 composite with a dual function, acting as a catalytic initiator that governs polymerization and microstructure, while simultaneously serving as a reinforcing and photocatalytic phase. The system exhibits high polymerization efficiency, reaching conversions up to 99% with low filler loadings (0.1–1.0 wt%). Structural analyses confirm polymer formation and reveal modifications in ester groups associated with coordination-driven mechanisms. Notably, the presence of TiO2–SiO2 promotes increased PLA tacticity, directly influencing mechanical performance. The resulting materials show enhanced tensile strength (~250,000 Pa) and Young’s modulus (1.5–2.0 MPa) compared to conventional systems. In addition, excellent photocatalytic activity was achieved, with up to 99.7% degradation of methyl orange. These findings demonstrate a synergistic strategy to simultaneously control polymer structure and functionality, positioning PLA/PCL–TiO2–SiO2 systems as promising multifunctional materials for environmental applications.

The dynamic growth of global maize production results in the generation of large amounts of residues originating from both cultivation and processing, creating a need to develop efficient and sustainable management pathways. The aim of this study was to evaluate the feasibility of utilizing selected maize-derived residues (straw, cobs, technical maize, and post-fermentation DDGS) for the production of densified solid fuels based on biochar obtained through pyrolysis at 500 °C. The study included analyses of the mineral composition of biomass and biochar, determination of biochar yield, ash content, and higher heating value (HHV). The biochar yield ranged from 30.19% to 42.49%, with the highest values obtained for DDGS (dried distillers grains with solubles). The pyrolysis process led to an increase in HHV to 25.3–32.14 MJ/kg. These values are comparable to the calorific values of hard coal. The results indicate that biochar derived from maize residues may represent a promising feedstock for the production of solid fuels with increased energy density, while the ashes generated during their combustion show potential for agricultural applications.

The authors require two adjustments in the original manuscript [...]

This paper presents a collaborative optimization design methodology aimed at improving heat dissipation efficiency through the modulation of microstructural variations. The approach addresses the thermal protection requirements of high-temperature components, such as ceramic matrix composite turbine blades, which are subjected to complex and elevated thermal loads. Through the integration of numerical simulation and experimental validation, a bidirectional mapping model linking carbon nanotube (CNT) content with the macroscopic anisotropic thermal conductivity of the material was developed. Furthermore, a thermal conduction analysis and optimization framework for Ceramic Matrix Composite (CMC) high-temperature components under non-uniform thermal loads was established. This study expands the adjustable range of the material’s thermal conductivity by allowing flexible modulation of carbon nanotube content. The results demonstrate that this methodology effectively enhances the heat dissipation capacity of CMC materials in extreme thermal environments: the maximum surface temperature of the optimized flat plate is reduced by 8.96%, the peak temperature gradient is lowered by 46.64%, and the maximum thermal stress is decreased by 38.17%. This research provides new insights into the comprehensive integration of thermal dissipation requirements for CMC hot components.

The growing demand for sustainable energy sources has intensified research on the valorization of biomass residues as feedstocks for energy production. This scoping review provides a comprehensive analysis of recent technological approaches for converting coconut and açaí residues into energy carriers and bioenergy products. A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In addition to synthesizing the existing literature, this study evaluates the technology readiness level (TRL) of the reported conversion pathways based on the experimental evidence provided in the reviewed studies. The literature search was conducted using Scopus, Web of Science, and ScienceDirect, focusing on peer-reviewed publications between 2015 and 2025 that reported experimental or pilot-scale research on thermochemical, chemical, and physical conversion processes for coconut and açaí residues. The TRL assessment indicates that most technologies remain at laboratory validation stages, with only a limited number reaching pilot or prototype demonstration levels. Nevertheless, several pathways—particularly thermochemical and densification processes—show promising potential for decentralized bioenergy applications. These findings are especially relevant for regions where coconut and açaí value chains generate significant volumes of agricultural residues. Their valorization could support decentralized energy systems, improve residue management, and contribute to sustainable bioeconomy strategies. Overall, this review identifies the main technological advances, limitations, and research gaps associated with the energy conversion of coconut and açaí residues, providing insights for future technological development and deployment.

Green communities play a critical role in advancing sustainable development; however, evaluating their performance and identifying appropriate improvement strategies remain challenging due to uncertain, incomplete, and multidimensional information. This study formalizes three key processes essential to green community governance—sustainability evaluation, attribute reduction, and decision-rule generation—and proposes a rough set-based decision framework that integrates quantitative indicators, expert knowledge, and rule-based reasoning. Using empirical assessment data from Nantou County, the framework identifies the most influential determinants of community performance, including accessibility-related facilities, remote-area status, and socioeconomic conditions. The results reveal clear drivers of sustainable community performance. Remote villages lacking community hubs face structural barriers to participation. Communities without facilities supporting vulnerable groups tend to stall at the registration stage, while bronze-level villages require equity-focused engagement despite possessing stronger resource endowments. Notably, silver-level performance is consistently associated with moderate income levels and moderate income disparity, underscoring socioeconomic balance—rather than economic extremes—as a key precondition for stable sustainability advancement. Together, these findings provide interpretable, evidence-based guidance for policymakers and community managers to identify performance gaps and allocate resources more effectively.

This study develops a fully coupled thermo–hydro–mechanical (THM) finite-element model to investigate fracture-induced fluid loss in depleted formations. To address the issue of assuming a homogeneous, unfractured medium, this approach incorporates the effects of pre-existing or induced fractures. By integrating thermoelastic stresses, fluid flow, and transient heat transfer, the model provides a more accurate simulation of coupled interactions, enabling a deeper understanding of stress evolution and fracture aperture behavior under temperature variations. The results show that pressure depletion reduces horizontal principal stresses in an approximately linear manner, with the minimum horizontal stress being more sensitive. The influence of wellbore pressure is concentrated in the near-wellbore region (r/rw < 2), where it increases circumferential stress at low azimuths and exhibits an almost linear positive correlation with fracture aperture. Fracture length has a negligible effect on pore-pressure variations (≤0.19 MPa) but increases circumferential stress at high azimuths and enlarges the aperture near the wellbore. Temperature effects, through thermoelastic stresses, dominate local stress redistribution, with the 90° azimuth showing the strongest sensitivity. Higher injection temperatures increase circumferential and radial stresses while decreasing near-wellbore aperture, whereas lower temperatures produce the opposite response. Although temperature differences cause only minor changes in pore pressure and far-field stresses, they exert first-order control on near-wellbore width evolution and the likelihood of lost circulation. These findings indicate that coordinated optimization of wellbore pressure, fracture dimensions, and injection temperature under depletion conditions is important for mitigating fracture-induced fluid loss and improving drilling safety and efficiency.

Gas–liquid gravity displacement poses a significant risk to drilling safety. However, the underlying mechanisms governing this process under downhole high-temperature and high-pressure (HTHP) conditions in deep and ultra-deep wells remain poorly understood. In this study, a numerical simulation method based on the Volume of Fluid (VOF) model was developed to investigate gas–liquid gravity displacement behavior under downhole HTHP conditions. The model was validated against 200 data points from visual laboratory experiments, showing excellent agreement with a relative error below 8.58%. Using this validated model, we then conducted 330 numerical simulations to systematically investigate the characteristics of gravity displacement under downhole HTHP conditions. Compared with surface low-pressure conditions, gravity displacement under downhole HTHP is markedly different, characterized by a narrower displacement window, lower gas influx (e.g., 99.5% reduction at −1500 Pa vs. surface conditions) and loss rates, and a smoother gas–liquid interface. As fracture width decreases, both gas influx and drilling fluid loss rates decline nonlinearly, and the displacement window contracts significantly. A critical fracture width for the onset of gravity displacement was identified, ranging from 0.3 to 0.5 mm depending on downhole conditions such as equivalent depth, drilling fluid density, and viscosity. Furthermore, increasing drilling fluid density expands the displacement window and increases the drilling fluid loss rate, whereas higher viscosity reduces both gas influx and drilling fluid loss rates. In contrast, fracture roughness exhibits minimal influence on gravity displacement. These findings provide practical criteria for optimizing well control strategies, thereby reducing drilling risks and improving operational safety. These findings advance the fundamental understanding of gravity displacement and contribute to a theoretical basis for improving drilling safety in deep fractured gas reservoirs.