Search Results (169)

India’s aviation sector, crucial for connectivity, economic growth, and national integration, faces sustainability measurement challenges focused solely on carbon emissions. This study proposes the Aviation Sustainability Performance Index (ASPI-India), spanning four pillars: Environmental Stewardship, Social Responsibility, Governance Maturity, and Economic Resilience. Measurable indicators are derived from regulatory filings, commercial flight databases, geospatial tracking, and targeted surveys. Data sources include DGCA safety audits, AAI operational statistics, ADS-B flight path data, and passenger satisfaction surveys from 2010 to 2024. Fixed-effects panel models link ASPI-India to operational and financial outcomes like load factor stability, CASK, and credit rating resilience. Quasi-experimental designs exploit policy shocks through difference-in-differences estimation. Factor analysis validates the four-pillar structure, and robustness checks compare entropy, PCA, and equal weighting. Results show that a one-standard-deviation increase in ASPI-India improves load factor stability, ancillary revenue share, and credit terms, especially for carriers with diversified route networks. The framework provides actionable insights for airlines, regulators, and investors to embed sustainability in aviation management. Full article

In this contribution, two silsesquioxane–cyclopentadienyl titanium complexes featuring one or two chloride ancillary ligands, [Ti(η⁵-C₅H₄SiMeO₂Ph₇Si₇O₁₀-κO)Cl₂] (1) and [Ti(η⁵-C₅H₄SiMe₂OPh₇Si₇O₁₁-κ²O₂)Cl] (2), were synthesized and evaluated in the Ziegler–Natta polymerization of styrene and the ring-opening polymerization (ROP) of L-lactide, respectively. Complex 1, activated with methylaluminoxane (MAO), catalyzed the syndiotactic polymerization of styrene with turnover frequencies up to 28 h⁻¹, affording polymers with narrow dispersity, low number-average molecular weights (M_n = 5.2–8.2 kDa), and high stereoregularity, as confirmed by ¹³C NMR. Complex 2, in combination with benzyl alcohol, promoted the ring-opening polymerization of L-lactide in solution at 100 °C, achieving conversions up to 95% with good molecular weight control (M_n close to theoretical, Đ = 1.19–1.32). Under melt conditions at 175 °C, it converted up to 3000 equiv. of monomer within 1 h. Kinetic analysis revealed first-order dependence on monomer concentration. The results highlight the ability of these complexes to produce syndiotactic polystyrene with narrow molecular weight distributions and to catalyze controlled ROP of L-lactide under both solution and melt conditions. Computational studies provided insight into key structural and energetic features influencing reactivity, offering a framework for further catalyst optimization. This work broadens the application scope of silsesquioxane–cyclopentadienyl titanium complexes and supports their potential as sustainable and versatile catalysts for both commodity and biodegradable polymer synthesis. Full article

Microgrids (MGs) have emerged as pivotal players in the energy transition by enabling the efficient integration of distributed energy resources and the provision of ancillary services to the power system. Despite their technical capabilities, MGs still face economic and regulatory barriers that hinder their widespread deployment in electricity markets. This paper presents a structured methodological framework to assess the economic viability of MGs delivering services such as peak shaving, loss compensation, and voltage support, among others. The proposed approach considers three distinct scenarios: (1) MGs supplying energy to local loads, (2) hybrid MGs combining local supply with ancillary services, and (3) MGs exclusively dedicated to ancillary services. The framework incorporates adjusted levelized cost of electricity (LCOE), levelized avoided cost of electricity (LACE), and net value metrics, while accounting for tax incentives and market price signals. A case study based in Colombia (Cali and Camarones) validates the framework through simulations conducted in HOMER Pro V3.18.4 and MATLAB Online. The results indicate that remuneration schemes based on availability and service utilization significantly enhance the viability of MGs. The proposed methodology is applicable to emerging regulatory environments and offers guidance for designing public policies that promote the active participation of MGs in supporting grid operations. Full article

The process of dissection is essential to the study of anatomy, with the variety of colours, shapes, patterns and textures revealing the distinctive features of each anatomical system, but it can also be misleading, because while the body’s constituent ‘parts’ have traditionally been classified according to their appearance, assumed functions and perceived importance, this basic information can be interpreted in different ways. Living organisms are intrinsically indeterminate, which implies that the conclusions arrived at through the study of anatomy are not necessarily congruent with the anatomical reality, and the abstract classifications of the connective tissues (CTs) are a case in point. This paper highlights a seventeenth-century interpretation of CT anatomy that was pushed aside as the musculoskeletal duality assumed functional dominance and relegated the fascial tissues to mere ancillary roles. In other words, an architectural framework of tensioned fibrous tissues that encompasses a complex body-wide heterarchy of space-filling compartments under compression and reasserts the structural significance of the soft CTs. The problems with orthodox classifications are then discussed alongside a mechano-structural role for the ‘loose’ fibrillar network: a closed-chain kinematic system that guides changes in the relative positions of adjacent compartments and refutes the notion of fascial ‘layers’. Full article

With the integration of high-penetration renewable energy, existing uniform marginal pricing mechanisms face critical challenges, including difficulty in recovering flexibility resource capacity costs and free-riding phenomena caused by renewable energy’s variability. To address these issues, this paper proposes a differentiated pricing mechanism for renewable energy based on analytical uncertainty representation to avoid marginal price distortion and promote the rational allocation of ancillary service costs. Firstly, a joint clearing model for energy and reserve ancillary service is developed, incorporating a distributional robust chance constraint based on moment information to model the uncertainty of renewable energy. Then, the composition structure of the nodal marginal price for ancillary service demand is redefined, offering clearer and more explicit price signals compared with traditional uniform marginal pricing. After that, quantification of the impact of energy storage on renewable energy forecast errors and ancillary service pricing is conducted, with a systematic analysis of its role in reducing ancillary service costs and optimizing generation revenue. Simulation results on the modified IEEE 30-bus system demonstrate significant advantages over traditional uniform pricing: the proposed mechanism ensures fair cost allocation, effectively mitigates free-riding problems, and provides clear economic signals. With energy storage units regulating renewable power output, it could lead to a 12.9% reduction in ancillary service costs while increasing total generation revenue by 6.73%. Full article

The electrochemical oxidation of anodic metal (cobalt, nickel, zinc or cadmium) in a cell containing an acetonitrile solution of the ligand (E)-N-(2-(((2-hydroxynaphthalen-1-yl)methylene)amino)phenyl)-4-methylbenzenesulphonamide (H₂L) affords complexes with the general formula [ML] (M = Co, Ni, Zn and Cd). Additionally, it was possible to obtain complexes with the general formula [MLL′] when L′ = 2,2-bipyridine (2,2-bpy), 4,4-bipyridine (4-4′-bpy) or 1,10-phenanthroline (phen) was present in the electrolytic cell. All of the compounds obtained have been characterized via microanalysis, IR spectroscopy, mass spectrometry, UV–visible spectroscopy and, in the case of diamagnetic compounds, via ¹H NMR spectroscopy. Further structural and electronic characteristics of these adducts have been obtained via DFT simulations. The compounds NEt₄[CoL₂] (1), [NiL(H₂O)] (2), [NiL(CH₃CN)(H₂O)]₂ (3), [Ni₂L₂(4,4′-bpy)] (4), [Zn₂L₂(MeOH)₂] (5) and [ZnL(2,2′-bpy)](CH₃CN) (6) have been characterized via X-ray diffraction. In this paper, we present a detailed study of the different behavior of the above-mentioned ligand depending on the metal and/or the presence of ancillary ligands. Full article

Battery energy storage systems (BESS) are considered a good energy source to maintain supply and demand, mitigate intermittency, and ensure grid stability. The primary contribution of this paper is to provide a comprehensive overview of global energy markets and a critical analysis of BESS’ participation in frequency control ancillary service (FCAS) markets. This review synthesises the current state of knowledge on the evolution of the energy market and the role of battery energy storage systems in providing grid stability, particularly frequency control services, with a focus on their integration into evolving high-renewable-energy-source (RES) market structures. Specifically, solar PV and wind energy are emerging as the main drivers of RES expansion, accounting for approximately 61% of the global market share. A BESS offers greater flexibility in storage capacity, scalability and rapid response capabilities, making it an effective solution to address emerging security risks of the system. Moreover, a BESS is able to provide active power support through power smoothing when coupled with solar photovoltaic (PV) and wind generation. In this paper, we provide an overview of the current status of energy markets, the contribution of battery storage systems to grid stability and flexibility, as well as the challenges that BESS face in evolving electricity markets. Full article

Amidst global imperatives for sustainable energy and environmental remediation, carbon aerogels (CAs) present a transformative alternative to conventional carbon materials (e.g., activated carbon, carbon fibers), overcoming limitations of disordered pore structures, unmodifiable surface chemistry, and functional inflexibility. This review systematically examines CA-based electrochemical systems as its primary focus, analyzing fundamental charge-storage mechanisms and establishing structure–property–application relationships critical to energy storage performance. We critically assess synthesis methodologies, emphasizing how stage-specific parameters govern structural/functional traits, and detail multifunctional modification strategies (e.g., heteroatom doping, composite engineering) that enhance electrochemical behavior through pore architecture optimization, surface chemistry tuning, and charge-transfer kinetics acceleration. Electrochemical applications are extensively explored, including the following: 1. Energy storage: supercapacitors (dual EDLC/pseudocapacitive mechanisms) and battery hybrids. 2. Electrocatalysis: HER, OER, ORR, and CO₂ reduction reaction (CO₂RR). 3. Electrochemical processing: capacitive deionization (CDI) and electrosorption. Beyond this core scope, we briefly acknowledge CA versatility in ancillary domains: environmental remediation (heavy metal removal, oil/water separation), flame retardancy, microwave absorption, and CO₂ capture. Full article

This study analyzed the frequency control challenges within the West Africa Power Pool Interconnected Transmission System (WAPPITS) as it plans to incorporate variable renewable energy (VRE) resources, such as wind and solar energy. Concerns center on the ability of WAPPITS primary frequency control reserves to adapt to high VRE penetration given the synchronization and frequency control problems experienced by the three separate synchronous blocks of WAPPITS. Optimizing solutions requires a better understanding of WAPPITS’ current frequency control approach. This study used questionnaires to understand operators’ practical experience with frequency control and compared these observations to field tests at power plants and frequency response metrics during system events. Eight (8) of ten (10) Transmission System Operators (TSOs) indicated that primary frequency control service was implemented in the TSO, but nine (9) of ten TSOs indicated that the reserves provided were inadequate to meet system needs. Five (5) of ten (10) respondents answered “yes” to the provision of secondary frequency control service, while only one (1) indicated that secondary reserves were adequate. Three (3) TSOs indicated they have AGC (Automatic Generation Control) installed in the control room, but none have implemented it for secondary frequency control. The results indicate a significant deficiency in primary control reserves, resulting in a reliance on under-frequency load shedding for primary frequency control. Additionally, the absence of an AGC system for secondary frequency regulation required manual intervention to restore frequency after events. To ensure the effectiveness of battery energy storage systems (BESSs) and the reliable operation of the WAPPITS with a higher penetration of inverter-based VRE, this paper recommends (a) implementing and enforcing basic primary frequency control structures through regional regulation and (b) establishing an ancillary services market to mobilize secondary frequency control resources. Full article

This study examines the feasibility of deploying renewable energy sources and storage systems to provide ancillary services (ASs), traditionally supplied by conventional power systems, in an electric-island power grid. As renewable energy penetration grows, grid stability becomes increasingly challenged as reduced system inertia and higher variability occur. The study focuses on Israel, which currently lacks operational AS markets. This research explores regulatory, economic, and technical mechanisms to enable renewables and storage systems to provide such services, using a comparative analysis of Germany and California, US, as use cases, along with interview analysis with experts from the Israeli energy sector. The findings highlight, on the one hand, notable regulatory and infrastructural barriers limiting the ability of alternative sources to provide ancillary services. On the other hand, the feasibility and importance of integrating renewables and storage, as regulatory adjustments, market-based procurement mechanisms, and incentive schemes, are to be undertaken. Adopting a structured AS market in Israel, influenced by international best practices, can improve grid resilience, allowing higher renewable integration and supporting long-term energy security and sustainability. Full article

With the rapid development of a new power system under the “dual carbon” goal, pumped storage has gained increasing attention for its role in integrating renewable energy and enhancing power system flexibility and security. This study proposes a dynamic benefit evaluation method for pumped storage projects, addressing the limitations of static analyses in capturing the evolving benefit trends. In this paper, the multi-stage dynamic benefit evaluation model was constructed by introducing time-of-use tariffs, periodic capacity pricing mechanism, and ancillary service revenue prediction based on machine learning and the multiple regression method. Sensitivity analysis was applied to explore the impact of key parameter variations on economic indicators. The results show that the benefit structure differs significantly across stages, and with electricity market development, a diversified pattern supported by electricity, capacity, and ancillary service revenues will emerge. The application of the model to an actual operating pumped storage power station yielded an internal rate of return of 8.18%, a payback period of 16.4 years, and a 26% increase in net present value compared with traditional methods. The proposed model expands the theoretical framework for pumped storage benefit evaluation and provides strong support for investment decisions, policy design, and operational strategy optimization. Full article

Remote sensing approaches can be cost-effective for estimating forest structural attributes. This study aims to use airborne LiDAR data to assess the robustness of multispectral satellite imagery and topographic attributes derived from DEMs to predict the density of three vegetation layers in a wet eucalypt forest in Tasmania, Australia. We compared the predictive capacity of medium-resolution Landsat-8 Operational Land Imager (OLI) surface reflectance and three pixel sizes from high-resolution WorldView-3 satellite imagery. These datasets were combined with topographic attributes extracted from resampled LiDAR-derived DEMs and a geology layer and validated with vegetation density layers extracted from high-density LiDAR. Using spectral bands, indices, texture features, a geology layer, and topographic attributes as predictor variables, we evaluated the predictive power of 13 data schemes at three different pixel sizes (1.6 m, 7.5 m, and 30 m). The schemes of the 30 m Landsat-8 (OLI) dataset provided better model accuracy than the WorldView-3 dataset across all three pixel sizes (R² values from 0.15 to 0.65) and all three vegetation layers. The model accuracies increased with an increase in the number of predictor variables. For predicting the density of the overstorey vegetation, spectral indices (R² = 0.48) and texture features (R² = 0.47) were useful, and when both were combined, they produced higher model accuracy (R² = 0.56) than either dataset alone. Model prediction improved further when all five data sources were included (R² = 0.65). The best models for mid-storey (R² = 0.46) and understorey (R² = 0.44) vegetation had lower predictive capacity than for the overstorey. The models validated using an independent dataset confirmed the robustness. The spectral indices and texture features derived from the Landsat data products integrated with the low-density LiDAR data can provide valuable information on the forest structure of larger geographical areas for sustainable management and monitoring of the forest landscape. Full article

Global industrialization has intensified the emission of emerging contaminants (ECs), posing a serious threat to the environment and human health. Persulfate-based advanced oxidation processes (PS-AOPs) have become a research hotspot due to their efficient degradation capability and environmentally friendly features; carbon-based materials are ideal catalysts for activating persulfate (PS) due to their tunable electronic structure, abundant active sites, and low cost. This study summarizes the application of carbon-based materials (graphene, single-atom catalysts (SACs), etc.) in PS-AOPs, and provides insights into the degradation mechanisms of radicals (e.g., sulfate radical (SO₄^−·), hydroxyl radical (·OH)) and non-radicals (e.g., ¹O₂(singlet oxygen), electron transfer). The removal efficacy of carbon-based catalysts for antibiotics, phenols, and dyes was compared, and the key degradation pathways were elucidated. In addition, the activation of PS can be accelerated, and catalytic efficiency can be improved by synergizing with ancillary technologies (e.g., light, electricity). Despite the great potential of carbon-based catalysts, their large-scale application is limited by the complexity of the catalyst preparation process and the lack of selectivity for complex water qualities. Future studies can accelerate the practical application of PS-AOPs in wastewater treatment through the precise design of SACs and the construction of multi-mechanism synergistic activation systems. Full article

In our research aimed at replacing precious transition metals like platinum with abundant base metals such as nickel for efficient triplet emitters, we synthesized and studied Ni(II) complexes [Ni(L^NHR)Cl]. These complexes containing the N^C^N cyclometalating dipyridyl-phenide ligand, equipped with pending H-bonding amine groups (NH(C₆H₅) (L^NHPh) and NH(C₆H₅CH₂), ClL^NHBn). Molecular structures determined from experimental X-ray diffractometry and density functional theory (DFT) calculations in the ground state showed marked deviation of the Cl⁻ coligand (ancillary ligand) from the ideal planar coordination, with τ₄ values of 0.35 and 0.33, respectively, along with hydrogen bonding interactions of the ligand NH function with the Cl⁻ coligand. The complexes exhibit long-wavelength absorption bands at approximately 425 nm in solution, with the experimental spectra being accurately reproduced through time-dependent density functional theory (TD-DFT) calculations. Vibrationally structured emission profiles and steady-state photoluminescence quantum yields of 30% for [Ni(L^NHPh)Cl] and 40% for [Ni(L^NHBn)Cl] (along with dual excited state lifetimes in the ns and in the ms range) were found in frozen 2-methyl-tetrahydrofuran (2MeTHF) glassy matrices at 77 K. Furthermore, within a poly(methyl methacrylate) matrix, the complexes showed emission bands centered at around 550 nm within a temperature range from 6 K to 300 K with lifetimes similar to 77 K. Based on TD-DFT potential scans along the metal–ligand (Ni–N) coordinate, we found that in a rigid environment that restricts the geometry to the Franck-Condon region, either the triplet T₅ or the singlet S₄ state could contribute to the photoluminescence. Full article

Shrubland vegetation plays a crucial role in ecological processes, but its conservation is facing threats due to climate change, wildfires, and human activities. Unmanned Aerial Vehicles (UAVs), or ‘drones’, have become valuable tools for detailed vegetation mapping, providing high-resolution imagery and 3D models despite challenges such as legal restrictions and limited coverage. We developed a methodology for estimating vegetation height, map vegetation classes, and fuel models by using multitemporal UAV data (imagery and point clouds from the imagery) and other ancillary data to provide insights into habitat condition and fuel characteristics. Two different random forest classification methods (an object- and a pixel-based approach) for discriminating between vegetation classes and fuel models were developed and compared. The method showed promise for characterizing vegetation structure (shrub height), with an RMSE of less than 0.3 m and slight overestimation of taller heights. For discriminating between vegetation classes and fuel models, the best results were obtained with the object-based random forest approach, with overall accuracies of 0.96 and 0.93, respectively. Although some difficulties were encountered in distinguishing low shrubs and brackens and in distinguishing low-height fuel models due to the spatial mixture, accurate results were obtained for most classes. Future improvements include refining terrain models by including data acquired with UAV aerial scanners and exploring different phenological stages and machine learning approaches for classification. Full article