Hybrid Configuration Research Articles

Clustering of tropical species through multivariate analysis of the bonding properties of edge-glued panels (EGP)

Tropical woods have high added value, and the use of waste for panel production is an initiative to add more value to this material, typically consisting of various species. The use of raw materials from tropical solid wood waste in the Amazon region contributes to the reduction of carbon emissions associated with the burning of this material. In this context, this study aimed to cluster species based on the bonding properties of Amazonian woods by applying multivariate analysis. The apparent density 12% and strength of finger joint and edge-glued joints of Cedrela odorata, Enterolobium schomburgkii, Erisma uncinatum and Qualea paraensis was evaluated which were joined in homogeneous and hybrid configurations with the adhesives PVA and EPI, as spreading rate of 180 g/m2. The treatments were compared by multivariate analysis of variance and discriminant analysis. The discrimination of species and combinations based on wood density (low, medium, and high) revealed that this is the most important characteristic for grouping different species that make up tropical hardwood waste for the production of EGP panels. In practice, the separation of species into groups according to wood densities can contribute to a better definition of the indications for use of edge glued panels of each density class, and assertive targeting for applications according to the strength ranges required. In the static bending, parallel tensile and shear tests all species and their combinations met the minimum requirements normative, indicating the approval of species and combinations studied for the production of EGP panels.

Optimization for fuel consumption and TCO of a heavy-duty truck with electricity-propelled trailer

As renewable energy grows in the heavy-duty truck sector, exploration of diverse solutions with varied energy types and powertrain configurations becomes a necessity. While most studies focus on powertrain configurations in tractors, this study takes a different approach: propose and evaluate new plug-in hybrid configurations with multiple power sources for heavy-duty trucks. The tractor retains its engine powertrain, while the trailer is equipped with electric axle(s), forming a fuel-electricity hybrid propulsion system. The specifications of the electric propulsion system are optimized, using a multi-objective particle swarm optimization algorithm and dynamic programming control algorithm to evaluate the energy consumption and total cost of ownership (TCO). The results highlight the potential of the configuration with three electric axles and single reduction gear in regard to vehicle energy consumption. Conversely, the configuration with one electric axle and a two-speed transmission exhibits the lowest TCO. Under the China World Transient Vehicle Cycle, the fuel consumption of the diesel truck is reduced by up to 44.59 % with the use of the optimized hybrid configuration. The truck's TCO can be then reduced by up to 832 thousand CNY in one-million-kilometer operation. For an actual road operation, these figures change to 34.79 % and 284 thousand CNY, respectively.

Adaptive Reactive Power Management with Thyristor-Controlled Transformer and Fixed Capacitor

The objective of this article is to develop and analyse a thyristor-controlled transformer with a fixed capacitor for reactive power compensation in power systems. Reactive power compensation is crucial for enhancing the efficiency and stability of power systems by reducing power losses, improving voltage profiles, and minimizing equipment stress. Traditional compensation methods often rely on fixed capacitors, reactors, or static VAR compensators, but these systems lack the flexibility required for dynamic control of reactive power under varying load conditions. The proposed approach integrates a thyristor-controlled transformer with fixed capacitors, allowing for precise, real-time adjustment of reactive power flow. The novelty of this article lies in the hybrid configuration of the thyristor-controlled transformer and fixed capacitor, which provides a cost-effective and robust solution compared to conventional systems. Unlike traditional methods that depend solely on switching capacitors or reactors, the use of thyristors allows for fine-tuning of reactive power, offering improved performance under variable loading conditions without the need for complex control algorithms. This setup enhances the adaptability of reactive power management, thus maintaining optimal power factor and voltage regulation. The findings from the simulation and experimental results demonstrate significant improvements in power factor correction, voltage stabilization, and reduction in harmonic distortion. The proposed system exhibits a faster response time and greater control accuracy compared to existing compensation techniques. These advantages make the thyristor-controlled transformer with a fixed capacitor a promising alternative for power utilities seeking to enhance the operational efficiency and reliability of their networks. This article contributes to the advancement of reactive power compensation technologies, providing a scalable solution suitable for modern power system.

Selective Void Deposition by Continuous, Ultrathin Ag Film Enabled Stable, High-Performance AgNWs-Based Transparent Heaters.

Metallic nanowire-based transparent conductors (MNTCs) are essential to various technologies, including displays, heat-regulating windows, and photo-communication. Hybrid configurations are primarily adopted to design stable, high-functioning MNTCs. Although hybrid MNTCs enhance electrical performance, they often suffer from optical degradation due to losses associated with the hybrid layers. Highly conductive hybrid MNTCs with minimal reduction in transparency are achieved with AgNWs/Ag(O)/Al-doped ZnO (AZO) design. The design provides a high visible light transmittance of 95.1%, representing a minimized optical loss of 3% compared to pristine AgNWs by optimizing optical interference between the AZO and Ag(O) layers. Furthermore, it allows for enhanced mobility of metallic nanowires by controlling the selective formation of conductive layers in the voids of the nanowire networks. The oxygen additive enables a continuous Ag ultrathin film of 6nm in the macro-voids of AgNWs system, corresponding to 25 times higher mobility for AgNWs/Ag(O)/AZO than that of sole AgNWs. The significant enhancement in the mobility of AgNWs/Ag(O)/AZO induces a reduction of sheet resistance of MNTCs by 73%. The AgNWs/Ag(O)/AZO, with an optimized sheet resistance of 24 Ω sq-1, is explored for transparent heater applications, demonstrating a fast thermal response with reliable stability, as evidenced by consistent high-temperature profiles during prolonged operation.

Mixed Mode‐I/II interlaminar fracture toughness Characterization of woven Carbon–Kevlar interyarn hybrid textile composites

AbstractIn actual service conditions, the composite structures are subjected to the combined effect of Mode‐I and Mode‐II loadings. It has great significance in the aerospace, defense, military, automobile, and marine sectors. This study aims to determine the Mixed Mode‐I/II interlaminar fracture toughness (ILFT) of plain and twill woven carbon, Kevlar monolithic, and interyarn hybrid textile composites under several hybridization schemes. The tailored properties are obtained using the interyarn hybridization of high stiff carbon yarn and high tough Kevlar yarn. The effect of individual yarn in the length direction in different hybrid composite laminates is carefully investigated. The Mixed Mode‐I/II ILFT characterization is experimentally performed using a mixed mode bending (MMB) test specimen on the Instron 8862 system under 45%, 55%, and 65% Mixed Mode ratios (MMRs). The increase in mode mixture percentage decreases the lever length, increases the load‐bearing capacity, and increases the Mixed Mode‐I/II ILFT of the MMB test specimen. Plain woven composites exhibited a higher ILFT than twill woven textile composites. The plain woven carbon–Kevlar hybrid composite laminate with carbon yarn‐in‐length direction shows the highest Mixed Mode‐I/II ILFT after CP laminates. Hybridization significantly increases the Mixed Mode‐I/II ILFT compared to monolithic Kevlar fabric‐reinforced composites. Moreover, the failure mechanisms are investigated using scanning electron microscopy.Highlights Mixed Mode‐I/II ILFT of carbon–Kevlar interyarn hybrid textile composites. ILFT at nonlinearity (NL), VIS, and 5%/Max load points for 45%, 55%, and 65% MMR. Advantage of placing carbon yarn‐in‐length direction in hybrid configurations. Effect of carbon–Kevlar interyarn hybridization on Mixed Mode‐I/II ILFT. Fractography of tested specimens to investigate several failure mechanisms.

Mechanical and shape-memory properties of TPMS with hybrid configurations and materials

ABSTRACT Triply periodic minimal surface (TPMS) structures with excellent properties of stable energy absorption, light weight, and high specific strength could potentially spark immense interest for novel and programmable functions by combining smart materials, e.g. shape memory polymers (SMPs). This work proposes TPMS lattices with hybrid configurations and materials that are composed of viscoelastic and shape-memory materials with the aim to bring temperature-dependent mechanical properties and additional dissipation mechanisms. Different configurations and diverse materials of polylactic acid (PLA), fiber-reinforced PLA, and polydimethylsiloxane (PDMS) are induced, generating five types of TPMS lattices, including (Schoen’s I-WP) IWP uniform lattice, IWP lattice with density gradient, hybrid configurations, hybrid materials, and filled PDMS, which are fabricated by 3D printing. The fracture morphologies and the distribution of carbon fibers are demonstrated via scanning electron microscopy with a focus on the influence of carbon fiber on shape-memory and mechanical properties. Shape recovery tests are conducted, which proves good shape memory properties and reusable capability of TPMS lattice. The combined methods of experiments and numerical simulation are adopted to evaluate mechanical properties, which presents multi-stage energy absorption ability and tunable vibration isolation performances associated with temperature and hybridization designs. This work can promote extensive research and provide substantial opportunities for TPMS lattices in the development of functional applications.

Enhancing compressive behaviour of seawater sea sand concrete filled hybrid carbon-glass FRP tubes exposed to seawater: Effect of thickness

This study presents a novel investigation into the impact of tube thickness on the residual compressive strength of sea water sea sand concrete (SWSSC) filled filament wound hybrid fibre-reinforced polymer (HFRP) tubes, positioning them as innovative alternatives to traditional concrete-filled steel tubes in corrosive marine environments. The research explores tube thicknesses of 2 mm, 3 mm, and 4 mm, employing a unique hybrid configuration of 50 % carbon fibre reinforced polymer (CFRP) internal layers and 50 % glass fibre reinforced polymer (GFRP) external layers. This study examines the effect of these configurations on compressive mechanical properties, microstructural characteristics, and damage progression under alkaline and seawater conditions. Additionally, the research evaluates cross-ply and hoop orientations as variables in filament winding fibre orientation. A comprehensive set of 108 hybrid tubes were filled with an alkaline solution to simulate the SWSSC environment and exposed to seawater at varying temperatures and durations. Accelerated aging experiments were conducted in the laboratory to assess the long-term compressive performance of SWSSC-filled HFRP tubes exposed to seawater. Long-term compressive strength predictions were made using the Arrhenius theory, based on short-term accelerated aging data. The accelerated test data revealed maximum compressive strength reductions of 33 %, 15 %, and 17 % for 2 mm, 3 mm, and 4 mm cross-ply HFRP tubes, respectively, after 150 days of exposure at 60 °C. For hoop HFRP tubes, the corresponding reductions were 19 %, 18 %, and 17 %. Thicker tubes (3 mm and 4 mm) with sufficient internal CFRP layers protect external GFRP layers from alkaline damage, akin to pure CFRP tubes. Thinner tubes (2 mm) exhibit similar performance to GFRP tubes as alkaline damage spreads from their less substantial internal CFRP layers to the outer GFRP layers. For cross-ply tubes, the recommended strength reduction factors are 0.6 for 2 mm, 0.8 for 3 mm, and 0.8 for 4 mm thicknesses. For hoop tubes, the suggested factors are 0.7 for 2 mm, 0.7 for 3 mm, and 0.8 for 4 mm thicknesses. This study shows the innovative potential of tailored hybrid HFRP tubes in enhancing the durability and performance of marine infrastructure.

Optimal performance of silicon nanowire solar cells under low sunlight concentration and their integration as bottom cells in III–V multijunction systems

Nanostructured silicon solar cells are designed to minimize costs through reduced material usage while enhancing power conversion efficiency via superior light trapping and shorter charge separation distances compared to traditional planar cells. This study identifies the optimal conditions for nanoimprinted silicon nanowire (SiNW) solar cells to achieve maximum efficiency under low sunlight concentration and evaluates their performance as bottom cells in III–V multijunction solar cell systems. The findings indicate that the SiNW solar cell reaches its peak performance at a concentration factor of 7.5 suns and a temperature of 40°C or lower. Specifically, the absolute conversion efficiency under these conditions is 1.05% higher than that under unconcentrated light. Compared to a planar silicon solar cell under identical conditions, the SiNW solar cell exhibits a 3.75% increase in conversion efficiency. Additionally, the SiNW single-junction solar cell, when integrated in series with a commercial lattice-matched InGaP/GaAs dual-junction solar cell, was tested under unconcentrated sunlight, specifically at one-sun, global air mass 1.5 condition, to assess its viability in one-sun multi-junction solar cell applications. The results suggest that a III–V upper subcell with a smaller active area than that of the SiNW subcell is optimal for maximizing current production, which is favorable to the cost reduction of the device. This hybrid configuration is particularly advantageous for terrestrial applications, such as electric vehicles, which demand lightweight, high-performance multijunction solar cell devices. Although the weight reduction of the characterized SiNW solar cell with a full silicon substrate compared to its planar solar cell counterpart is 1.8%, recommendations to increase this reduction to as much as 64.5% are discussed to conclude this paper.

Aerodynamic analysis of rotor-to-rotor interactions in different octocopter configurations

Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different octocopter configurations amid hover and forward flight. Conventional and coaxial configurations are studied and a hybrid configuration is also proposed to rectify the disadvantages associated with the earlier two. Comparison is carried out for the aforementioned configurations along with comparison of coaxial and hybrid octocopters with bigger diameter rotors in the same confined space for high thrust requirement missions. Vertical spacing of coaxial configuration is also studied. Virtual Blade Method (VBM) is considered herein due to its great computational efficiency. The results show that there are 11.89% and 14.22% loss in thrust for coaxial octocopter compared to conventional and hybrid configurations with normal size rotors and 15.61% loss compared to hybrid configuration with bigger rotors in hover, whereas coaxial square configuration performs the worst in forward flight with a lift loss of 9.1%, 14.77% and 18.8% compared to coaxial diamond, conventional and hybrid configurations with normal size rotors and 9.96% and 17.82% loss compared to coaxial diamond and hybrid configurations with bigger rotors. Combined FM shows that hybrid configuration outperforms other octocopter configurations in overall aerodynamic performance.

Techno-economic and environmental analysis of biogas-based hybrid renewable energy systems: A case study for a small-scale livestock farm

Biogas technology offers a significant benefit in enabling energy generation from distributed sources of biomass through its easy scalability. This study aimed to conduct the technical, economic, and environmental analysis of biogas-based hybrid renewable energy systems in a small-scale livestock farm located in the rural area of the Central Anatolia region in Türkiye. The HOMER software was used to analyze a total of five scenarios. These scenarios are hybrid combinations of a biogas generator, PV panels and wind turbines. The hybrid scenarios were evaluated by comparing them to each other and to the base scenario, which only has a grid connection. The optimal system has been determined to be the grid-connected Biogas/PV panel hybrid configuration, with an energy cost of 0.0688 $/kWh and a net present cost of $70,777. The optimal system has a renewable fraction of 89.9 % and a CO2 emissions mitigation potential of 13,066 kg/year compared to the base scenario. Furthermore, sensitivity analysis for various input parameters such as grid sellback rate, interest rate and load demand was performed to assess the impact of changes in these parameters on the system. Sensitivity analysis results show that increased grid sellback rates can significantly enhance financial metrics and reduce the payback period from 13.13 years to 6.63 years.

Guessing Human Intentions to Avoid Dangerous Situations in Caregiving Robots

The integration of robots into social environments necessitates their ability to interpret human intentions and anticipate potential outcomes accurately. This capability is particularly crucial for social robots designed for human care, as they may encounter situations that pose significant risks to individuals, such as undetected obstacles in their path. These hazards must be identified and mitigated promptly to ensure human safety. This paper delves into the artificial theory of mind (ATM) approach to inferring and interpreting human intentions within human–robot interaction. We propose a novel algorithm that detects potentially hazardous situations for humans and selects appropriate robotic actions to eliminate these dangers in real time. Our methodology employs a simulation-based approach to ATM, incorporating a “like-me” policy to assign intentions and actions to human subjects. This strategy enables the robot to detect risks and act with a high success rate, even under time-constrained circumstances. The algorithm was seamlessly integrated into an existing robotics cognitive architecture, enhancing its social interaction and risk mitigation capabilities. To evaluate the robustness, precision, and real-time responsiveness of our implementation, we conducted a series of three experiments: (i) A fully simulated scenario to assess the algorithm’s performance in a controlled environment; (ii) A human-in-the-loop hybrid configuration to test the system’s adaptability to real-time human input; and (iii) A real-world scenario to validate the algorithm’s effectiveness in practical applications. These experiments provided comprehensive insights into the algorithm’s performance across various conditions, demonstrating its potential for improving the safety and efficacy of social robots in human care settings. Our findings contribute to the growing research on social robotics and artificial intelligence, offering a promising approach to enhancing human–robot interaction in potentially hazardous environments. Future work may explore the scalability of this algorithm to more complex scenarios and its integration with other advanced robotic systems.

Integration and Optimization of Multisource Electric Vehicles: A Critical Review of Hybrid Energy Systems, Topologies, and Control Algorithms

Electric vehicles (EVs) are pivotal in addressing the escalating environmental crisis. While EV drivetrains excel compared to those of vehicles with internal combustion engines (ICEs), their energy storage systems are hampered by limited range, lifespan, and lengthy charging times. Hybrid energy storage systems (HESSs) present a viable current solution to these issues. This review thoroughly explores the state of the art in the emerging field of multisource EVs that utilize HESSs, incorporating any combination of batteries (BTs), supercapacitors (SCs), flywheels (FWs), fuel cells (FCs), and/or transmotors. In addition, the paper systematically categorizes and evaluates different hybrid configurations, detailing potential topologies and their respective advantages and limitations. Moreover, the paper examines diverse control algorithms used to manage these complex systems, focusing on their effectiveness and operational efficiency. By identifying current research gaps and technological challenges, this study aims to delineate future research directions that could enhance the deployment and optimization of multisource EVs, thereby addressing critical challenges such as energy density, system reliability, and cost-effectiveness.

Optimal design and techno-economic analysis of a solar-wind hybrid power system for laayoune city electrification with hydrogen and batteries as a storage device

The pressing environmental concerns associated with fossil fuels have propelled renewable energy sources, particularly solar and wind energy, into a more prominent position. This article aims to explore an optimal configuration and conduct a technical and economic analysis of a hybrid solar-wind energy system tailored for electrifying Laayoune city. This system, equipped with hydrogen tank and batteries as storage devices, aims to meet the annual energy requirements of residential areas estimated at 310.87 GWh/year. In addition to addressing energy needs, the study tackles significant challenges such as reducing dependence on traditional energy sources, curbing greenhouse gas emissions, and bolstering energy security in the region. Utilizing HOMER Pro software, the research evaluates various combinations of renewable resources, including solar and wind, alongside storage solutions such as batteries, fuel cells, and hydrogen storage, to find the most viable solution in terms of electricity generation, cost, and environmental impact. The findings highlight a hybrid configuration comprising solar, wind, battery, grid, and converter components as the most cost-effective approach for Laayoune's renewable energy system. This integrated system not only yields an energy cost of 0.0477 $/kWh and a net present cost (NPC) of 336 M$ but also generates 627.69 GWh/year of energy. Furthermore, it achieves a 100% renewable energy ratio while completely eliminating CO2 emissions.

Integration Assessment of Renewable Energy Sources (RESs) and Hydrogen Technologies in Fish Farms: A Techno-Economical Model Dispatch for an Estonian Fish Farm

A fundamental aspect of fish farms is their energy consumption, which is essential for various activities like water supply, pool aeration, thermal conditioning, lighting, filtration, and recirculation systems. Due to volatile prices and rising energy use, costs have surged, requiring energy-optimization solutions for economic viability and pollution reduction. In this context, this study aims to evaluate renewable energy integration in these installations based on real data, assessing current operations, proposing renewable energy optimization, and exploring hydrogen systems for energy needs, using HOMER PRO® to analyze different scenarios. For this purpose, it targets a rainbow trout farm in Estonia, and by simulating the various hybrid configurations proposed, it aims to optimize its energy production and storage, ensuring feasibility and technical integration. The results of the simulations primarily demonstrate the potential for using the byproduct of electrolysis to cover the oxygen demand in these types of processes, reducing the demand for raw materials. Additionally, it is observed that storage enhances performance in isolated systems; however, the economically viable integration of hydrogen technology requires three assumptions: a regulatory framework allowing surplus energy sales to the grid, an existing infrastructure for hydrogen trading, and high energy purchase prices.

Buckling of Thin-Walled Angle Column Made of Hybrid Laminate Under Axial Compression

This paper presents the investigation of eigenproblem for angle columns made flax, carbon laminates. The first three eigenmodes were determined and corresponding critical load values for columns subjected to axial compression. The analysis was made for six configurations. Each of them had the same arrangement of layers. The effect of changing the material of individual layers on bifurcation load values was analyzed. The obtained values were related to the K1 configuration, for carbon and flax-carbon configurations the differences in the values of bifurcation load in relation to the all-flax configuration were determined for all 3 modes. Interpreting the achieved results, it was concluded that replacing the relevant layers of flax laminate with carbon layers could increase the operating range of the system in the linear area. Moreover, for hybrid configurations, the effect of using a single carbon layer versus using a pair of carbon layers on the critical load value was investigated. Analysis of the results showed that for the selected configurations, a higher bifurcation load value was obtained with the use of a single carbon layer compared to the use of a pair of symmetric carbon layers. The conducted research indicates the need to study this topic in more depth, due to the possibility of increasing the work of the system in the linear range while reducing the cost and environmental impact of the material used.

Benzene-1,4-dicarboxylic acid-based Ni-MOF for efficient battery-supercapacitor hybrids: Electrochemical behavior and mechanistic insights

Hybrid supercapacitors, integrating both Faradaic and non-Faradaic mechanisms, have emerged as promising energy storage devices due to their high energy density and excellent cycling stability. In the pursuit of sustainable energy storage solutions, the development of advanced materials has garnered significant attention. Herein, we report the Benzene-1,4-dicarboxylic acid-based nickel metal-organic framework (Ni MOF) for application in battery supercapacitor hybrid configuration. The Ni MOF was synthesized via a simple and scalable hydrothermal method, resulting in a mixed nanorods structure. The electrochemical setup of bare electrode uncovers its marvelous electrochemical profits with specific capacity of 678.23C/g (3 mV/s) and 565.32C/g (1.2 A/g). A predominant diffusive nature of Ni-MOF (92.76 % at 3 mV/s) was revealed via simulation approach that back these profits. Furthermore, the asymmetric supercapacitor assembled with the Ni MOF along activated carbon exhibited high specific capacity (197.20C/g), along with outstanding specific energy and power (46.56 Wh/kg 850 W/kg respectively). Besides, persuasive rate capability (43.19 % conservation of specific energy while boosting the specific power to 10 times) along with splined cyclic life was observed. The findings unveil Ni-MOF as an excellently tailored and eco-conscious choice for electrode materials in advanced energy storage devices, driving advancements in sustainable energy technologies.

Enhanced turbine endwall cooling using crescent-dimpled film cooling holes and a hybrid configuration: numerical study

The current study proposed a novel crescent-dimpled film cooling hole and investigated its aerothermal performance on the turbine endwall when a row of the film holes are arranged in front of the stator. The mainstream Reynolds number based on the inlet velocity and the axial chord length of the vane was 150,000, and the blowing ratio ranged from 0.5 to 1.5. Besides, a hybrid configuration combining the advantages of the cylindrical and crescent-dimpled holes was also investigated. RANS simulations using Shear Stress Transport (SST) k–ω turbulence model were conducted. The numerical simulations show that the pure crescent-dimpled hole design enhances the adiabatic film cooling effectiveness by 32.3 %, 52.3 %, and 43.6 % at blowing ratios of 0.5, 1.0, and 1.5, respectively. Correspondingly, the net heat flux reduction (NHFR) values are 22.9 %, 57.9 %, and 63 % higher than the cylindrical holes. The high film cooling effectiveness behind the film cooling hole prevents the additional thermal load caused by the dimple-induced heat transfer enhancement. Using cylindrical holes near the leading edge and crescent-dimpled holes elsewhere, the hybrid arrangement suppresses the passage vortex and further enhances the film cooling effectiveness and NHFR by 51.9 % and 93.8 % at BR = 1.5, respectively. The streamlines and vortex structures show that the crescent dimple at the hole’s exit diffuses the coolant, thereby enhancing the film cooling in the lateral direction. Flow separation occurs behind the dimple, which reduces the jet momentum and attracts the jet towards the wall. The curved surface of the dimple directs the horseshoe vortex in front of the jet to the side, and anti-CRVP is formed. These are responsible for the film cooling enhancement by the crescent dimple.

Comparative Study on the Performances of a Hinged Flap-Type Wave Energy Converter Considering Both Fixed and Floating Bases

The dynamical modeling and power optimization of floating wind–wave platforms, especially in regard to configurations based on constrained floating multi-body systems, lack in-depth systematic investigation. In this study, a floating wind-flap platform consisting of a flap-type wave energy converter and a floating offshore wind turbine is solved in the frequency domain considering the mechanical and hydrodynamic couplings of floating multi-body geometries and a model that suits the constraints of the hinge connection, which can accurately calculate the frequency domain dynamic response of the flap-type WEC. The results are compared with bottom-fixed flap-type wave energy converters in the absence of coupling with a floating wind platform. Moreover, combined with traditional optimization methods of power take-off systems for wave energy conversion, an optimization method is developed to suit the requirements of floating wind-flap platform configurations. The results are drawn for a specific operation site in the South China Sea, whereas a sensitivity analysis of the parameters is performed. It is found that the floating wind-flap platform has better wave energy absorption performance in the low-frequency range than the bottom-fixed flap-type wave energy converter; the average power generation in the low-frequency range can increase by up to 150 kW, mainly due to constructive hydrodynamic interactions, though it significantly fluctuates from the sea waves’ frequency range to the high-frequency range. Based on spectral analysis, operational results are drawn for irregular sea states, and the expected power for both types of flap-type WECs is around 30 kW, which points to a similar wave energy absorption performance when comparing the bottom-fixed flap with the flap within the hybrid configuration.

Optical steelyard: high-resolution and wide-range refractive index sensing by synergizing Fabry–Perot interferometer with metafibers

Refractive index (RI) sensors play an important role in various applications including biomedical analysis and food processing industries. However, developing RI sensors with both high resolution and wide linear range remains a great challenge due to the tradeoff between quality (Q) factor and free spectral range (FSR) of resonance mode. Herein, the optical steelyard principle is presented to address this challenge by synergizing resonances from the Fabry–Perot (FP) cavity and metasurface, integrated in a hybrid configuration form on the end facet of optical fibers. Specifically, the FP resonance acting like the scale beam, offers high resolution while the plasmonic resonance acting like the weight, provides a wide linear range. Featuring asymmetric Fano spectrum due to modal coupling between these two resonances, a high Q value (~ 3829 in liquid) and a sensing resolution (figure of merit) of 2664 RIU−1 are experimentally demonstrated. Meanwhile, a wide RI sensing range (1.330–1.430 in the simulation and 1.3403–1.3757 in the experiment) is realized, corresponding to a spectral shift across several FSRs (four and two FSRs in the simulation and experiment, respectively). The proposed steelyard RI sensing strategy is promising in versatile monitoring applications, e.g., water salinity/turbidity and biomedical reaction process, and could be extended to other types of sensors calling for both high resolution and wide linear range.

An experimental investigation into crashworthiness of filament wound intra-yarn hybrid glass/jute epoxy composites tubes under quasi-static axial and lateral compression

The increasing demand for sustainable materials in the automotive industry has driven the research towards exploration of natural fiber composites for crash structures. This study investigates the quasi-static axial and lateral crushing behavior of hybrid glass/jute fiber epoxy tubes. Intra-yarn hybrid mixing ratios of jute and glass fibers were tested to evaluate the feasibility of using natural fibers as eco-friendly alternatives to traditional synthetic composites. A total of five different configurations were fabricated using filament winding process. The experimental results were analyzed for collapsing behavior, failure modes, and energy absorption characteristics. The hybrid epoxy tubes revealed fiber-matrix fracturing, local buckling, and delamination as three primary failure modes under crushing tests. The hybrid configuration with 25 % jute fiber and 75 % glass fiber demonstrated optimal crashworthiness performance, achieving the highest specific energy absorption (SEA) values of 15.85 J/g under axial loading and 2.96 J/g under lateral loading. The configurations with higher jute content of 50 % and 75 %, showed decreasing SEA and crush force efficiency (CFE) values, with brittle fracturing and delamination as dominant failure modes, indicating a trade-off between weight and energy absorption efficiency. The neat glass fiber configuration maintained nearly consistent CFE values of 0.55 and 0.56, between axial and lateral loadings respectively, demonstrating isotropic behavior in energy absorption. Conversely, the neat jute fiber configuration improved SEA to 12.14 J/g under axial loading but exhibited significant limitations under lateral loading, with SEA decreasing to 0.69 J/g. Visual examination of crushed samples highlighted local buckling in GF configurations and brittle fracturing in hybrid and neat jute fiber configurations. The scanning electron microscope (SEM) analysis provided detailed insights into the microstructural characteristics and failure mechanisms, highlighting the inter-laminar debonding between the jute and glass fibers in hybrid configuration. By evaluating the combined effects of hybridization and loading conditions, the present study contributes to developing eco-friendly and efficient materials for automotive safety, aligning with industry sustainability goals.