A comprehensive review and future challenges of energy-aware path planning for small unmanned aerial vehicles with hydrogen-powered hybrid propulsion

Unmanned aerial vehicles (UAVs) with fully electric propulsion systems mainly use lithium-based batteries. However, using fuel cells, hybrid propulsion systems are created to improve the flight time and payload capacity of the UAVs. Energy management and energy-aware path planning are important aspects to be explored in hybrid-propulsion powered UAV configurations. These facilitate optimal power distribution among energy sources and motion planning considering energy consumption, respectively. In the literature, although there are many studies on the energy management of hybrid-powered UAVs and path planning of only battery-powered UAVs, there are research gaps in energy-aware path planning of hybrid-powered UAVs. Additionally, the energy management of hybrid-powered UAVs is usually considered independent of path planning in the literature. This paper thoroughly reviews recent energy-aware path planning for small UAVs to address the listed critical challenges above, providing a new perspective and recommendations for further research. Firstly, this study evaluates the recent status of path planning, hydrogen-based UAVs, and energy management algorithms and identifies some challenges. Later, the applications of hydrogen-powered UAVs are summarised. In addition, hydrogen-based hybrid power system topologies are defined for small UAVs. Then, the path-planning algorithms are classified, and existing studies are discussed. Finally, this paper provides a comprehensive and critical assessment of the status of energy-aware path planning of UAVs, as well as detailed future work recommendations for researchers.The first author would like to acknowledge support from the Scientific and Technological Research Council of Türkiye (TÜBITAK) for funding his research visit scheme to Cranfield University for the project work (Appl. no.: 1059B192301276; REF: 53325897-115.02-476393).The Aeronautical Journa

Assessment of hydrogen storage and pipelines for hydrogen farm

This paper presents a thorough initial evaluation of hydrogen gaseous storage and pipeline infrastructure, emphasizing health and safety protocols as well as capacity considerations pertinent to industrial applications. As hydrogen increasingly establishes itself as a vital energy vector within the transition towards low-carbon energy systems, the formulation of effective storage and transportation solutions becomes imperative. The investigation delves into the applications and technologies associated with hydrogen storage, specifically concentrating on compressed hydrogen gas storage, elucidating the principles underlying hydrogen compression and the diverse categories of hydrogen storage tanks, including pressure vessels specifically designed for gaseous hydrogen containment. Critical factors concerning hydrogen gas pipelines are scrutinized, accompanied by a review of appropriate compression apparatus, types of compressors, and particular pipeline specifications necessary for the transport of both hydrogen and oxygen generated by electrolysers. The significance of health and safety in hydrogen systems is underscored due to the flammable nature and high diffusivity of hydrogen. This paper defines the recommended health and safety protocols for hydrogen storage and pipeline operations, alongside exemplary practices for the effective implementation of these protocols across various storage and pipeline configurations. Moreover, it investigates the function of oxygen transport pipelines and the applications of oxygen produced from electrolysers, considering the interconnected safety standards governing hydrogen and oxygen infrastructure. The conclusions drawn from this study facilitate the advancement of secure and efficient hydrogen storage and pipeline systems, thereby furthering the overarching aim of scalable hydrogen energy deployment within both energy and industrial sectors.Energie

Exploring advanced and sustainable bioaugmentation-enhanced ultrafiltration processes for the removal of emerging contaminants

The development of cost-effective and sustainable water treatment technologies is crucial for supporting the water sector and the public in achieving global sustainable development goals (SDG 6) and carbon neutrality targets. Ultrafiltration (UF), known for its compactness, relatively high performance, and ease of operation, has been widely deployed in water treatment. However, its limitations in removing some emerging contaminants (ECs) and membrane fouling issues have hindered its broader application. This study investigated the incorporation of bioaugmented filtration into conventional UF processes to enhance ECs removal and mitigate membrane fouling during the treatment of real drinking water sources. In addition to effectively removing microorganisms (eukaryotes and bacteria), polysaccharides (13.9%), and inorganic pollutants (CaCO3, MgO, SiO2, and Al2O3), the proposed approach also demonstrated superior removal (4.6%–100.0%) of four target ECs (atenolol, carbamazepine, trimethoprim, and sulfamethoxazole) compared to direct UF process (1.5%–47.5%). After 56 days of operation, the bioaugmented pre-treatment significantly reduced transmembrane pressure (TMP) by 80.2% compared to the direct UF process. Mechanisms studies further reassured that ECs removal followed oxidation during bioaugmentation pre-treatment. The time-of-flight secondary ion mass spectrometry with in-depth analysis capability (around 5 nm) revealed that the UF membrane primarily removed atenolol through adsorption. The toxicity prediction results of typical ECs and their degradation intermediates indicated a significant reduction in ecological risk for most intermediates. The findings from this work demonstrate the feasibility of using low-carbon and few-chemical water treatment technologies to secure drinking water quality.China National Petroleum Corporation (China), National Natural Science Foundation of China, Youth Innovation Promotion AssociationThis work was financially supported by the National Natural Science Foundation of China (52322001, 52388101, 52070183), the Program of the Excellent Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y2023010), and the China National Petroleum Corporation (2023ZZ1305).Journal of Membrane Scienc

Supplementation strategies to control propionic acid accumulation resulting from ammonia inhibition in dry anaerobic digestion: osmoprotectants, activated carbon and trace elements

Propionic acid accumulation in anaerobic digestion is a common sign of inhibition at high ammonia levels. To mitigate accumulation three supplementations were tested: osmoprotectants, trace elements and activated carbon. Activated carbon and osmoprotectants (MgCl2) achieved a 28 % increase in methane yield and a 3-fold reduction in hydrogen partial pressure compared with the control. Trace elements supplementation increased methane formation by 18 % without preventing instability. No supplementation avoided propionic accumulation, although MgCl2 delayed it. Activated carbon and MgCl2 supported proliferation of strict hydrogenotrophs, increasing microbial redundance with expected positive impacts on process resilience. Evidence beyond previous studies on the role of retention time as a control parameter of versatile archaea's methanogenic pathway is also provided. As retention time is reduced, syntrophic acetate oxidising bacteria are washed out of the system, likely resulting from an increase in their doubling time with inhibitors accumulation, preventing hydrogenotrophic methanogenesis and supporting previous observations of Methanosarcina being forced to conduct acetoclastic methanogenesis. Longer retention times to accommodate longer doubling times or alleviation of inhibition with activated carbon and MgCl2 supported retention of syntrophic acetate oxidising bacteria, enabling strict hydrogenotrophic archaea to proliferate. These supplementations would allow operation of industrial scale ADs at shorter retention times and higher throughputs. Results suggest that osmoprotectants and activated carbon addition were linked to a reduction in archaea's osmotic pressure and enhanced direct interspecies transfer, respectively, leading to increased methane formation despite propionic levels.Engineering and Physical Sciences Research CouncilThis work was undertaken during I. Rocamora’s Engineering Doctorate research at Cranfield University, funded jointly by the Engineering & Physical Sciences Research Council (EPSRC) Skills Technology Research and Management (STREAM) EngD Programme (Grant EP/ L015412/1) and Thalia Waste Management.Journal of Environmental Chemical Engineerin

CRISPR-enabled genetic logic circuits for biosensing

Synthetic biology aims to engineer genetic circuits for custom-designed behaviors in living systems, including sophisticated biosensing applications. The CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) system has gained attention for its potential in genetic circuit design due to its modularity, programmability, precision, and orthogonality. Here we highlight the current CRISPR-based tools for gene regulation at both transcriptional and translational levels. We discuss how these CRISPR technologies facilitate the design and construction of complex genetic circuits that can perform customized logic computations within living systems. Furthermore, we summarize the applications of CRISPR-based genetic logic circuits in biosensing, emphasizing their potential for detecting diverse biological and environmental signals. Finally, we highlight the key challenges facing the development and application of CRISPR-enabled genetic logic circuits and propose directions for future research to overcome these bottlenecks.This work was supported by National Natural Science Foundation of China (32320103001, 32271475), “Pioneer” and “Leading Goose” R&D Program of Zhejiang (2024C03011), National Key R&D Program of China (2023YFF1204500), Beijing Life Science Academy (2024200CA0070), Kunpeng Action Program Award of Zhejiang Province, and China Postdoctoral Science Foundation (2022M722780). ZY thanks Leverhulme Trust Research Leadership Award (RL-2022-041) and Leverhulme Trust Visiting Professorship grant (VP1-2024-030).TrAC Trends in Analytical Chemistr

A review of flexible fluid-structure interactions in the ocean: progress, challenges, and future directions

Flexible Fluid-Structure Interaction (FFSI) has emerged as an important, but challenging research direction in modern ocean engineering. This line of research gradually evolved in response to the pressing need to model the dynamic responses of ships and marine structures to sea loads; to predict the performance of flexible marine propellers, energy converters, and coastal protection systems; and to understand the mutual interactions between sea ice, marine vegetation, and mud with oceanic and coastal processes occurring near the surface and seabed. This review presents the state of knowledge and art of modelling of FFSI in the maritime environment, tracing research progress from early physical tests to high-fidelity computational ones emerged recently. Flexible wave–structure interaction, global ship hydroelasticity, hydroelastic slamming, flexible marine propellers, vegetation dynamics, and wave–mud interactions are covered. Limitations and strengths of existing models, and the challenges that remain are discussed in-depth, and it is concluded that FFSI-based research in ocean engineering has very well grown, though some gaps are still open. In specific, hydroelastic effects are still overlooked in the design practices and classification rules do not fully incorporate them, and there are still concerns regarding uncertainties related to FFSI modelling of flexible slamming, dynamic of flexible marine vegetation, and wave-mud interactions. Hence, future research must bridge computational modelling with real-world applications, expand benchmarking coverage for marine engineering problem, and incorporate AI-based methods for modelling FFSI problems, predicting related dynamic responses, or accelerating simulations.Ocean Engineerin

A simulation framework for zoom-aided coverage path planning with UAV-mounted PTZ cameras

Achieving energy-efficient aerial coverage remains a significant challenge for UAV-based missions, especially over hilly terrain where consistent ground resolution is needed. Traditional solutions use changes in altitude to compensate for elevation changes, which requires a significant amount of energy. This paper presents a new way to plan coverage paths (CPP) that uses real-time zoom control of a pan–tilt–zoom (PTZ) camera to keep the ground sampling distance (GSD)—the distance between two consecutive pixel centers projected onto the ground—constant without changing the UAV’s altitude. The proposed algorithm changes the camera’s focal length based on the height of the terrain. It only changes the altitude when the zoom limits are reached. Simulation results on a variety of terrain profiles show that the zoom-based CPP substantially reduces flight duration and path length compared to traditional altitude-based strategies. The framework can also be used with low-cost camera systems with limited zoom capability, thereby improving operational feasibility. These findings establish a basis for further development and field validation in upcoming research phases.Sensor

Alternative metallocenes in floating catalyst-CVD: synthesis of novel carbon nanostructures

Introduction: The floating catalyst chemical vapour deposition (FC-CVD) method is widely used for synthesising carbon nanotubes (CNTs), typically with ferrocene as the catalyst. This study explores the use of alternative, nonferrous metallocenes to investigate their impact on carbon nanostructure formation. Methods: Six metallocenes - ferrocene, cobaltocene, ruthenocene, vanadocene, manganocene, and magnesocene - were tested under comparable FC-CVD conditions. The resulting materials were characterised using scanning electron microscopy (SEM), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). Results and Discussion: Ferrocene produced vertically aligned CNT carpets with high crystallinity. Cobaltocene and magnesocene also yielded CNTs, though less aligned and more defective. Ruthenocene and vanadocene resulted in disordered graphitic carbon without nanotube morphology, confirmed by the presence of broad D and G bands in Raman spectra. Notably, manganocene catalysed the formation of dendritic structures with oxidised and functionalised surfaces, exhibiting unique morphologies distinct from conventional CNTs. Conclusion: These results highlight the ability of nonferrous metallocenes to direct the growth of unconventional carbon nanostructures. The findings suggest new possibilities for tailoring nanocarbon morphology through catalyst selection, particularly for applications requiring high surface area or chemical functionality.This research was funded by Warsaw University of Technology IDUB, POB Materials Technologies – 3 ADVANCED grant no1820/359/Z01/POB5/2021.Nanotechnology, Science and Application

Multi-fidelity design optimization of installed aero-engines with non-axisymmetric exhausts

Larger ultra-high bypass ratio (UHBR) aero-engines introduce an aerodynamic integration challenge. In close-coupled, podded underwing configurations, the aerodynamic interference between the propulsion system and the airframe could penalize the aircraft net vehicle force (NVF) and erode some of the novel cycle benefits and fuel burn reduction. Non-axisymmetric designs of the bypass nozzle can improve the performance of the aircraft by mitigating some of the penalizing effects induced by the integration of the powerplant. However, due to the prohibitive computational cost of the design methods, only lower-fidelity design approaches have been feasible in an industrial time-scale. This work develops a relatively low-cost multi-fidelity design optimization methodology for non-axisymmetric exhausts where the effects of the propulsion system installation are considered. The methodology combines inviscid and viscous aerodynamic data to formulate multi-fidelity surrogate models which drive a genetic algorithm (GA) optimization. The method enabled the incorporation of the viscosity effects in the optimization process at a reasonable computational cost and led to better designs relative to a methodology based only on lower-fidelity data. Overall, the optimization of non-axisymmetric exhausts can benefit the net vehicle force of the complete engine–aircraft system in cruise by up to 0.9% of the engine standard net thrust which can reduce fuel burn by a similar amount. The optimization with multi-fidelity surrogate models reduced the computational time by a factor of four relative to a method based only on viscous aerodynamic data.Rolls Royce and Cranfield UniversityJournal of Engineering for Gas Turbines and Powe

Solidago canadensis modifies microbial community and soil physicochemical properties through litter leachates and root exudates

Invasive plant inputs alter soil microbial communities via chemical compounds in litter, root exudates, and leachate, impacting a range of soil processes, but precise effects are poorly understood. We examined Solidago canadensis, a common invasive species in China, and its litter effects on soil microbial communities under natural conditions. Experimental treatments included S. canadensis seedling density (1 and 2 plants/pot) and quantity of litter (10 and 20 g/pot), with control groups that contained no plants or litter. After 120 days, soil samples were analyzed for physico-chemical properties, GC-MS chemical composition, and bacterial community composition using high-throughput sequencing. Results showed that S. canadensis seedlings and litter inputs increased soil pH, organic matter (SOM), and nitrogen (TN), while phosphorus and potassium remained unchanged. We identified 66 chemical compounds, predominantly ketones, alcohol, aldehyde, hydrocarbon, ester, acid, terpenoids, and alkaloids, associated with the presence of the invasive species, alongside shifts in dominant bacterial genera including Sphingomonas, Acidobacteriales, and Gemmatimonas. Rarer genera under the invasive treatment species, such as Candidatus, Rhodoplanes and Novosphingobium, correlated positively with soil TN, pH, and SOM. Collectively, our results demonstrate how the increased presence of allelochemicals from S. canadensis litter significantly impact soil properties and bacterial communities, and may therefore have implications for ecosystem dynamics.This work was supported by the National Natural Science Foundation of China (31971427), Carbon Peak and Carbon Neutrality Technology Innovation Foundation of Jiangsu Province (BK20220030), and the Young Scientist Fund of Jiangsu Province (BK20200905). Part of the funding for this research was supported by the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment and the Special Scientific Research Project of the School of Emergency Management, Jiangsu University. The authors would also like to thank the Researchers Supporting Project Number (RSPD2025R668), King Saud University, Riyadh, Saudi Arabia.Journal of Plant Ecolog