Field Energy Research Articles

Biomass: The accelerator for moving MOFs to practical applications

Mitigating the increasingly prominent energy and environmental issues arising from the rapid expansion of industry through the realization of green and sustainable development has become a global focus. Compared to traditional fossil energy sources, biomass resources offer a diverse range of supply channels. Therefore, in an industrial system dominated by fossil energy, the deep exploration and utilization of biomass resources are crucial for environmental restoration. Against the backdrop of “carbon peaking” and “carbon neutrality,” replacing traditional fossil fuels with biomass resources presents broad application prospects, promoting the utilization of environmental resources and pointing the way towards future green and circular development. Metal-organic Frameworks (MOFs), characterized by their high specific surface area, large porosity, and tunable properties, have garnered significant attention. However, due to the inherent powdered nature of MOFs, they pose challenges in practical applications, such as difficulties in recovery, pipeline blockages, and even secondary pollution. This issue can be addressed by compositing MOFs with other eco-friendly and renewable materials. Biomass resources are precisely such eco-friendly and renewable materials. Biomass/MOF composites, formed by integrating biomass with MOFs, combine the advantages of both materials, thereby expanding their practical application domains. This review explores the methods of preparing and applying functionalized new materials facilitated by the incorporation of biomass into MOFs, starting from various biomass raw materials. It thoroughly summarizes the research advancements of such materials in adsorption, catalysis, sensing, energy, and other fields. Additionally, it provides constructive suggestions on the issues encountered during the preparation and application processes, offering a scientific basis for researchers in designing and developing novel biomass/MOF composite materials.Abbreviations: MOFs, Metal-Organic Frameworks; NRs, combined with nanorods; PSM, post-synthetic modification; –OH, hydroxyl; –COOH, carboxyl; –CHO, aldehyde; MB, methylene blue; MD-Wood, modified wood; MS, cell walls of waste corn stalks; CS, corn stalks; PS, pine sawdust; PMS, peroxymonosulfate; OTC, oxytetracycline; DFT, density functional theory; AAMOFs, Amino acid metal–organic frameworks; SO, sage; CO, calendula; hetero-fNCs, flexible nitrogen-doped carbon heterostructures; BUBS, bionic ultra-black sponge; SO4•−, sulfate radicals; MN, melanin nanoparticles; CMC, carboxymethyl cellulose; ACW, eutrophic water; DC, desert cyanobacteria.

Entropy generation in Johnson–Segalman peristaltic flow with magnetic field and activation energy

AbstractThis study examines entropy generation in the peristaltic flow of Johnson–Segalman fluid through a curved channel, considering the effects of Hall and ion slip due to an externally applied magnetic field and activation energy. The fluid dynamics are modeled using a highly nonlinear mathematical framework, which is non‐dimensionalized and simplified with a lubrication approach. Numerical solutions are obtained using the shooting technique to analyze fluid flow properties. The results, presented graphically, provide a comprehensive understanding of the interactions between the non‐Newtonian characteristics of the Johnson–Segalman fluid, entropy generation, and activation energy effects. The study finds that increasing the Hall parameter enhances entropy generation. Higher activation energy increases the rate of chemical reactions and by‐products, raising system randomness. Additionally, reducing the channel curvature or increasing the curvature parameter elevates the system's entropy. These insights are valuable for biomedical and industrial applications.

Can we predict mixed grain boundaries from their tilt and twist components?

One of the major challenges towards understanding and further utilizing the properties and functional behaviors of grain boundaries (GB) is the complexity of general GBs with mixed tilt and twist character. Here, we report the correlations between mixed GBs and their tilt and twist components in terms of structure, energy and stress field by computationally examining 7440 silicon GBs. Such correlations indicate that low angle mixed GBs are formed through the reconstruction mechanisms between their superposed tilt and twist components, which are revealed as the energetically favorable dissociation, motion and reaction of dislocations and stacking faults. In addition, various complex disconnection network structures are discovered near the conventional twin and structural unit GBs, implying the role of disconnection superposition in forming high angle mixed GBs. By unveiling the energetic correlation, an extended Read-Shockley model that predicts the general trends of GB energy is proposed and confirmed in various GB structures across different lattices. Finally, this work is validated in comparison with experimental observations and first-principles calculations.

Magnetic field, magnetospheric accretion and candidate planet of the young star GM Aurigae observed with SPIRou

Abstract This paper analyses spectropolarimetric observations of the classical T Tauri star (CTTS) GM Aurigae collected with SPIRou, the near-infrared spectropolarimeter at the Canada–France–Hawaii Telescope, as part of the SLS and SPICE Large Programs. We report for the first time results on the large-scale magnetic field at the surface of GM Aur using Zeeman Doppler imaging. Its large-scale magnetic field energy is almost entirely stored in an axisymmetric poloidal field, which places GM Aur close to other CTTSs with similar internal structures. A dipole of about 730 G dominates the large-scale field topology, while higher-order harmonics account for less than 30 per-cent of the total magnetic energy. Overall, we find that the main difference between our three reconstructed maps (corresponding to sequential epochs) comes from the evolving tilt of the magnetic dipole, likely generated by non-stationary dynamo processes operating in this largely convective star rotating with a period of about 6 d. Finally, we report a 5.5σ detection of a signal in the activity-filtered radial velocity data of semi-amplitude 110 ± 20ms−1 at a period of 8.745 ± 0.009 d. If attributed to a close-in planet in the inner accretion disc of GM Aur, it would imply that this planet candidate has a minimum mass of 1.10 ± 0.30 MJup and orbits at a distance of 0.082 ± 0.002 au.

High Stability and Low Power Nanometric Bio-Objects Trapping through Dielectric-Plasmonic Hybrid Nanobowtie.

Micro and nano-scale manipulation of living matter is crucial in biomedical applications for diagnostics and pharmaceuticals, facilitating disease study, drug assessment, and biomarker identification. Despite advancements, trapping biological nanoparticles remains challenging. Nanotweezer-based strategies, including dielectric and plasmonic configurations, show promise due to their efficiency and stability, minimizing damage without direct contact. Our study uniquely proposes an inverted hybrid dielectric-plasmonic nanobowtie designed to overcome the primary limitations of existing dielectric-plasmonic systems, such as high costs and manufacturing complexity. This novel configuration offers significant advantages for the stable and long-term trapping of biological objects, including strong energy confinement with reduced thermal effects. The metal's efficient light reflection capability results in a significant increase in energy field confinement (EC) within the trapping site, achieving an enhancement of over 90% compared to the value obtained with the dielectric nanobowtie. Numerical simulations confirm the successful trapping of 100 nm viruses, demonstrating a trapping stability greater than 10 and a stiffness of 2.203 fN/nm. This configuration ensures optical forces of approximately 2.96 fN with an input power density of 10 mW/μm2 while preserving the temperature, chemical-biological properties, and shape of the biological sample.

Dynamic range and optimization strategies for radiochromic film calibration using gradient radiation fields.

This investigation aimed to optimize gradient positioning for radiochromic film calibration to facilitate a uniform distribution of calibration points. The study investigated the influence of various parameters on gradient dose profiles generated by a physical wedge, assessing their impact on the field's dose dynamic range, a scalar quantity representing the span of absorbed doses. Numerical parameterization of the physical wedge profile was used to visualize and quantify the impact of field size, depth, and energy on the dynamic range of dose gradients. This concept enabled the optimization of the gradient positioning and estimation of the necessary number of exposures for the desired calibration dose range. An optimization algorithm based on histogram bin height minimization was developed and presented. The maximum dynamic range was achieved with a 20 20 field size at 5 cm depth. Optimization of wedge gradient positioning yielded the most uniform dose distribution with 7 exposures for the [1,10] Gy range and 8 exposures for the [1,20] Gy range. Film calibration using gradients centered at 1.6, 3, 3.5, and 7 Gy central axis (CAX), obtained through optimized gradient positioning, was showcased. The presented work demonstrates the potential for an improved film calibration process, with efficient material utilization and enhanced dosimetric accuracy for clinical applications. While the method was described for the use of a physical wedge, the methodology can be easily extended to the use of a more convenient dynamicwedge.

Hot Deformation Behavior and Microstructure Evolution of a Graphene/Copper Composite.

Graphene/copper composites are promising in electronic and energy fields due to their superior conductivity, but microstructure control during thermal mechanical processing (TMP) remains a crucial issue for the manufacturing of high-performance graphene/copper composites. In this study, the hot deformation behavior of graphene/copper composites was investigated by isothermal compression tests at deformation temperatures of 700~850 °C and strain rates of 0.01~10 s-1, and a constitutive equation based on the Arrhenius model and hot processing map was established. Results demonstrate that the deformation mechanism of the graphene/copper composites mainly involves dynamic recrystallization (DRX), and such DRX-mediated deformation behavior can be accurately described by the established Arrhenius model. In addition, it was found that the strain rate has a stronger impact on the DRX grain size than the deformation temperature. The optimum deformation temperature and strain rate were determined to be 800 °C and 1 s-1, respectively, with which a uniform microstructure with fine grains can be obtained.

Synthesis and Properties of 12442-family Superconductor

We report a synthesis of two members of recently discovered high-temperature superconductors of 12442 family, with formula MCa2Fe4As4F2 (M=Rb, K) and transition temperatures of 32.7 and 34.6 K, respectively. Quality of the samples was assessed using X-ray powder diffraction, superconducting transitions were identified through transport and magnetic experiments. The temperature dependence of the upper critical field and vortex activation energy was investigated under magnetic fields up to 19 T. Two distinct thermally activated flux flow regimes were observed in both systems. Field dependences of activation energy U0(H) indicate a change in the properties of vortex matter in these regimes and distinctly different dissipation mechanisms, reminiscent of cuprate HTSC.

Reimagining Teaching Style Through Renewable Energy Quality Assessment—A Focus on Power Technology and Equipment

This article delves into teaching style translation strategies from the perspective of power energy quality assessment, using power technology and equipment as specific cases, with the aim of enhancing the international dissemination efficiency of power energy professional knowledge in the education field. Through detailed data analysis, this article reveals the rapid pace of technological updates and equipment upgrades in the power energy industry, especially in the fields of smart grids and renewable energy. As of 2023, the proportion of non fossil energy generation installed capacity worldwide has approached 50%, indicating that the power industry is accelerating its transition to green and low-carbon. This article pays special attention to the complex terms and concepts involved in the teaching of power technology and equipment. Using the principle of adaptability in translation theory, it analyzes how to accurately convey the precise meanings of these terms in the translation process, ensuring that international students can accurately understand and master key knowledge points. By comparing traditional teaching methods with a new teaching model that incorporates elements of power energy quality assessment, the study found that the latter performs more outstandingly in improving students' practical and problem-solving abilities. Specifically, the accuracy of students in simulating power system fault handling has increased by about 30%. In addition, this article also utilizes big data analysis technology to comprehensively sort out and evaluate teaching resources in the field of power energy, and finds that high-quality teaching materials and case sharing are crucial for improving teaching effectiveness. Based on the above analysis, this article proposes a series of optimization suggestions for teaching style translation, in order to provide strong support for the international education of power energy majors and promote the exchange and progress of global power energy technology.

Using Electroanalytical Techniques to Study Inhibition Mechanisms in Enzymes

Spectroscopic assays are typically utilized to study oxidoreductase enzyme kinetics, mechanisms, and inhibition. This talk will discuss the use of mediated and direct bioelectrocatalysis for studying kinetics followed by a thorough study of the effect of mediators in studying inhibition mechanisms. This will be followed up with strategies for studying mechanisms via direct bioelectrocatalysis. The talk will conclude with a discussion of the applications of these electroanalytical techniques in the fields of energy, sensing, and sustainable manufacturing.

(Invited) 1D Oxides for Energy, Environment, and Biomedical Applications: Are They as Good as They Appear?

1D oxides demonstrate interesting optical, electronic, catalytic, and surface properties. They are interesting not only because they can be synthesized using cost effective methods but also appear to be useful in several technological processes. They are also amenable to doping, composite formation, and assembly as heterostructures with a variety of elements as well as pre-formed materials such as dyes, metals, and non-metals.This talk will feature representative examples of 1D oxides and their composites in the field of energy, environment, and biomedical applications. Key findings using Titanium dioxide as the compound of focus will be highlighted. Research in this field from our group will be presented. Specific focus will be on the work involving former and current collaborators associated with India This presentation will also look into examples of work in the area that suggest not so promising benefits of these 1D oxides, thus raising the question of its actual benefits.

Preliminary Electrochemical Analysis of Carbon Nanoparticles from Candle Soot

Nanoparticles (NPs) generated by candle soot are of interest due to their potential applications. Because of their electronic properties, carbon-based zero-dimensional, one-dimensional, and two-dimensional nanomaterials such as graphene, fullerene, carbon nanotubes, and carbon nanofibers are extensively studied (1).However, synthesis of these nanomaterials is complex and expensive. Candle soot also contains fluorescent carbon NPswhich can be used for the preparation of fluorescent makers (2). The potential applications of candle soot NPs include energy storage [e.g., can be used for supercapacitor electrode material (3)], and conversion [fuel cells (4)]. Candle soot can be an excellent source of carbon NPs. In this presentation, we cover some challenges associated with carbon NPs, such as (a) instability of NPs due to agglomeration with time and increase in temperature and (b) separation and isolation of NPs. Thus, we focus on stabilization of NPs, isolation and characterization of NPs and to study electronic, optical, and electrochemical properties to determine whether they are promising candidate in the field of energy conversion.Candle soot formation depends on various parameters like substrate material, deposition time, flame temperature, wick dimension, and flame height (5). We developed a protocol for the collection of candle soot. With this proposed protocol, the carbon NPs generated from candle soot ranges from 50 nm to larger particle size which is confirmed by dynamic light scattering (DLS) technique shown in Fig. 1, and transmission electron microscope (TEM). We will include the electrochemical analysis such as investigation of oxidation/reduction processes to determine fundamental thermodynamic parameters of standard potential in organic solvents and aqueous solutions. References Jariwala, V.K. Sangwan, L.J. Lauhan, T.J. Marks, M.C. Harsam, Carbon nanomaterials for electronics, optoelectronics, photovoltaics, and sensing, Chem. Soc. Rev., 43 (2013), 2824-28.J. Campbell, M.J. Andrews, K.J. Stevenson, New nanotech from an ancient material: Chemistry demonstrations involving carbon-based soot, J. Chem. Educ., 89 (2012) 1280-1287.Zhang, D. Wang, B. Yu, F. Zhou, W. Liu, Candle soot as a supercapacitor electrode material, RSC. Adv., 4 (2014), 2586-2589.Khalakhan, R. Fiala, J. Laukova, P. Kus, A. Ostroverkh, M. Vaclavu, M. Vorokhta, I. Matolinova, V. Matolin., Candle Soot as an efficient support for proton exchange membrane fuel cell catalyst, Fuel Cell., 16 (2016) 652-655.N. Sahoo, B. kandasubramanian. An experimental design for the investigation of water repellent property of candle soot particles, Mater. Chem. Phys.,148 (2014), 134-142. Figure 1

Maximizing Quantum Hole Collection on Anatase TiO2 Thin Films with (001) Facets for Photoelectrochemical Oxigen Evolution Reaction Efficiency

Hydrogen production from water, a key element in the renewable energy portfolio, offers a solution to reduce reliance on fossil fuels. Photoelectrochemical (PEC) hydrogen production, using light-absorbing semiconductors and catalysts, offers a clean and cost-effective method for harnessing solar energy. To enhance the efficiency of PEC, this study explores the use of anatase TiO2 thin film photoelectrodes as an alternative to expensive and rare catalysts, aiming to generate hydrogen as a clean fuel with oxygen as a byproduct.Anatase titanium dioxide is a well-established functional material widely applied in the fields of environment and energy. Recognized as one of the premier materials for photocatalysis and a promising photoanode material for water splitting, titanium dioxide (TiO2) finds use in diverse applications such as dye-sensitized solar cells, perovskite-based solar cells, and cleaning devices. Its band gap of 3.2 eV, stability, strong absorption in the UV region, and energetics of the valence and conduction band edges make anatase particularly suitable for PEC water splitting, especially for the oxygen evolution reaction (OER).Our research focuses on the development of anatase thin films with strong [001] texture and (001) facets at the surface of the film. The (001) facets are known to accumulate photogenerated hole states while the [001] orientation imparts a negative flat band potential. We hypothesize that these two properties, (001) facets and [001] texture, are ideal for OER. This study combines these two structural characteristics within the semiconductor TiO2 layer to enhance PEC performance and maximize the efficiency of hole collection during water oxidation.Anatase TiO2 thin films with (001) facets and [001] orientation were hydrothermally synthesized on a fluorine-doped tin oxide (FTO) substrate and annealed at 500°C. The films exhibited [001] orientation and (001) faceting as shown by grazing incidence X-ray diffraction (GI-XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Photoelectrochemical measurements via cyclic voltammetry in a 0.1 M KOH and Na2SO3 solution demonstrated the films' hole collection efficiency under a 365 nm UV light source. The photoelectrochemical (PEC) and oxygen evolution reaction (OER) characteristics of anatase thin films were observed both under dark and light conditions. Prior to illumination, only the Ti3+/Ti4+ redox couple was observed with an onset potential of 0.01 V (RHE) and negligible OER at anodic potentials. When UV irradiated, the TiO2 thin films exhibited a photocurrent that increased through the anodic scan. The onset potential of photocurrent, measured in the presence of the hole scavenger, exhibited a negative shift ranging from -100 to -200 mV compared to the KOH onset potential. This shift is attributed to the film surface's limited efficiency in collecting holes for water oxidation at low potentials, as rapid recombination kinetics compete with water oxidation. Interestingly, the photocurrent observed with Na2SO3 electrolyte was 0.15 to 0.3 times more than what we saw with KOH electrolyte. Our preliminary results indicate a current density of ~2.0-2.5 mA cm-2 at 1.8 V and a hole collection efficiency of ~84 % at 1.23 V vs RHE, the thermodynamic water oxidation potential. In summary, we have made significant progress toward enhancing the PEC activity of anatase TiO2 thin films by optimizing the film structure for both reactivity and charge transport.

Understanding in-Plane Movement of Iridium in Proton Exchange Membrane Electrolyzer after Accelerated Stress Test

In the rapidly evolving field of clean energy, proton exchange membrane water electrolyzers (PEMWEs) stand at the forefront, heralding a new era of sustainable hydrogen fuel production. PEMWEs need to operate for at least 10 years and material degradation is a challenge that needs to be overcome. Here we use H2NEW accelerated stress (AST) protocol to degrade 5 cm2 PEMWE cell having low iridium loadings on the anode side. Using X-ray fluorescence (XRF) mapping, we first assessed the iridium distribution at the beginning of life (BOL) of the electrolyzer cell and then afterwards at the end of life (EOL). Regular electrical characterization with specific time intervals was conducted, such as collection of polarization curves, electrochemical impedance spectroscopy and cyclic voltammetry. Identical location was selected for iridium mapping. To complement XRF mapping, we also conducted X-ray diffraction (XRD) studies at the BOL and at the EOL. XRD reveals the crystalline structure and phase transitions of iridium, crucial for understanding how iridium’s atomic arrangement adapts to operational stresses. This comprehensive approach, combining XRF and XRD, aims to provide a multifaceted view of iridium’s behavior, distribution, and structural changes from the BOL to EOL. This research aims to unravel the behavior of iridium after AST, particularly whether it migrates into the ionomer, moves to the cathode, or undergoes other transformational shifts.Figure 1.micro-XRF map of iridium distribution on the anode of the PEMWE at the BOL. The map is 2 mm x 2 mm. Figure 1

Single Cells Polydopamine Coating of Rhodobacter Sphaeroides for Enhanced Electron Transfer

Photosynthetic bacteria are anoxygenic microorganisms with highly versatile metabolism, as they use sunlight to oxidize a broad variety of organic compounds in addition to heterotrophic and photoautotropic alternative metabolisms. Recent advances in coupling light-harvesting microorganisms with electronic components has led to a new generation of biohybrid devices based on microbial photocatalysts. These devices are limited by the poorly conductive interface between phototrophs and synthetic materials that inhibit charge transfer.Polydopamine (PDA), produced by self-assembly of dopamine, is a very versatile and bioinspired polymer with widespread applications1 mostly due its ability to adhere and cover surfaces of different chemical composition. The oxidative conditions employed for the formation of this dark insoluble polymer are mild and biocompatible and have inspired scientists to develop novel nanomaterials. Post-functionalization of PDA2 also enables fine tuning of properties. Furthermore, the ability of this monomer to self-assemble and polymerize in the bacterial growth medium was considered one of the requirements of the polymer to be used as coating material beside the tunable conductive properties and the flexible structure.Biocompatibility of dopamine was tested by in vivo addition in the growth media of the photosynthetic purple non sulphur Rhodobacter (R.) sphaeroides 3 in anoxygenic conditions. This study focuses on overcoming the bottleneck of biohybrid devices through the metabolically-driven encapsulation of photosynthetic cells with a bio-inspired conductive polymer. The treated cells show preserved light absorption of the photosynthetic pigments in the presence of dopamine concentrations ranging between 0.05 – 3.5 mM. The thickness and nanoparticle formation of the membrane-associated PDA matrix was further shown to vary with the dopamine concentrations in this range. Compared to uncoated cells, the encapsulated cells show up to a 20-fold enhancement in transient photocurrent measurements under mediatorless conditions. The biologically synthesized PDA can thus act as a matrix for electronically coupling the light-harvesting metabolisms of cells with conductive surfaces. 1Liu, Y.; Ai, K.; Lu, L. Polydopamine and its derivative materials: Synthesis and promising applications in energy, environmental, and biomedical fields. Chem. Rev. 2014, 114, 5057–5115. 2Buscemi, G., Vona, D., Ragni, R., Comparelli, R., Trotta, M., Milano, F., Farinola, G.M., Polydopamine/Ethylenediamine Nanoparticles Embedding a Photosynthetic Bacterial Reaction Center for Efficient Photocurrent Generation. Adv. Sustainable Syst. 2021, 2000303. 3 Labarile, R.; Varsalona, M.; Vona, D.; Stufano, P.; Grattieri, M.; Farinola, G. M.; Trotta, M., A novel route for anoxygenic polymerization of dopamine via purple photosynthetic bacteria metabolism. MRS Advances 2023

Development of Bromine Adsorbing Carbon Felt Electrode by Coating of Nitrogen-Doped Mesoporous Carbon Layer for Highly Stable Flowless Zinc-Bromine Battery

Renewable energy is well known for the extreme volatility of power production, and secondary battery-based energy storage systems (BESS) are the key to the novel and safe energy industry to expand the supply of renewable energy. Currently, lithium-ion battery-based ESS is commonly used, but the frequent ignition accidents from these ESSs rather become an obstacle to the growth of the renewable energy field. Among the redox batteries, the flowless zinc-bromine battery (FLZBB) is studied as the alternative since it uses a non-flammable and cost-effective aqueous Zn- Br2 electrolyte. However, its main challenges are that bromine (Br2) and polybromide anions (), formed at the positive electrode during the charging process, cross over to the negative electrode due to the difference in chemical potential between the electrodes. The diffused Br2 oxidizes the zinc metal, electrodeposited on the negative electrode, and causes a self-discharge reaction that consumes the charging active material and Br2 the battery performance and life. Herein, we present a nitrogen-doped mesoporous carbon coated on the pristine graphite felt fibers (NMC/GF). By uniformly forming a nitrogen-doped porous carbon material on the GF fibers through the evaporation-induced self-assembly (EISA) method, it is a simple and cost-effective method to develop the structural and properties of the GF positive electrode to increase the ability of adsorption and storing the active materials, Br2 and polybromide anions (,, and ) generated during the charging process. In addition, it also improved the bromine redox reaction kinetics by having a strong affinity with the aqueous Zn-Br2 electrolyte. This facilitates long-term charge/discharge cycles, enabling high performance and improved durability for Coulombic efficiency over 95% for 5000 cycles in the FLZBB single-cell platform at a current density of 20 mA cm-2 and a high-rate areal capacity of 2 mAh cm-2.

Review of Data-Driven Models in Wind Energy: Demonstration of Blade Twist Optimization Based on Aerodynamic Loads

With the increasing use of data-driven modeling methods, new approaches to complex problems in the field of wind energy can be addressed. Topics reviewed through the literature include wake modeling, performance monitoring and controls applications, condition monitoring and fault detection, and other data-driven research. The literature shows the advantages of data-driven methods: a reduction in computational expense or complexity, particularly in the cases of wake modeling and controls, as well as various data-driven methodologies’ aptitudes for predictive modeling and classification, as in the cases of fault detection and diagnosis. Significant work exists for fault detection, while less work is found for controls applications. A methodology for creating data-driven wind turbine models for arbitrary performance parameters is proposed. Results are presented utilizing the methodology to create wind turbine models relating active adaptive twist to steady-state rotor thrust as a performance parameter of interest. Resulting models are evaluated by comparing root-mean-square-error (RMSE) on both the training and validation datasets, with Gaussian process regression (GPR), deemed an accurate model for this application. The resulting model undergoes particle swarm optimization to determine the optimal aerostructure twist shape at a given wind speed with respect to the modeled performance parameter, aerodynamic thrust load. The optimization process shows an improvement of 3.15% in thrust loading for the 10 MW reference turbine, and 2.66% for the 15 MW reference turbine.

An Aluminum Anode with Superior Discharge Characteristics Prepared via Grain Refinement

AbstractAs Electric Vehicles became more important in the field of energy, the disadvantages of lithium‐ion batteries became apparent. This led to an increased interest in metal‐air batteries, particularly aluminum‐air batteries, as alternatives to lithium‐ion batteries. However, aluminum‐air batteries also have their own deficiencies, with one of the main areas of research being the improvement of anode characteristics. Improving anode characteristics is a crucial area of research in this field. Aluminum alloys have traditionally been used to overcome obstacles in creating batteries with favorable electrochemical properties. However, recent studies suggest that reducing the grain size of aluminum anodes can have positive effects. In this study, we investigated the electrochemical behavior of three aluminum alloys that were grain‐refined by Al‐5Ti‐1B and compared the results to a commonly used aluminum alloy as an anode in aluminum‐air batteries. We chose Al−Ti alloys with variable amounts of titanium (0.01, 0.05, and 0.1 wt.%) for evaluation. We selected a 4 molar potassium hydroxide solution as the test electrolyte due to the merits of alkaline electrolytes. Our study found that the alloy with 0.05 wt.% of titanium is the best anode choice. This anode has promising discharge characteristics at high current density (50 mA/cm2) and is an appropriate choice for electric vehicles.

Essential features of weak current for excellent enhancement of NOx reduction over monoatomic V-based catalyst

Human society is facing increasingly serious problems of environmental pollution and energy shortage, and up to now, achieving high NH3-SCR activity at ultra-low temperatures (<150 °C) remains challenging for the V-based catalysts with V content below 2%. In this study, the monoatomic V-based catalyst under the weak current-assisted strategy can completely convert NOx into N2 at ultra-low temperature with V content of 1.36%, which shows the preeminent turnover frequencies (TOF145 °C = 1.97×10−3 s−1). The improvement of catalytic performance is mainly attributed to the enhancement catalysis of weak current (ECWC) rather than electric field, which significantly reduce the energy consumption of the catalytic system by more than 90%. The further mechanism research for the ECWC based on a series of weak current-assisted characterization means and DFT calculations confirms that migrated electrons mainly concentrate around the V single atoms and increase the proportion of antibonding orbitals, which make the V-O chemical bond weaker (electron scissors effect) and thus accelerate oxygen circulation. The novel current-assisted catalysis in the present work can potentially apply to other environmental and energy fields.

Kaluza–Klein Schwinger Effect

Abstract We show that electric fields in compactified spaces may produce Kaluza–Klein (KK) particles even when the energy of the electric fields is smaller than the KK scale. As an illustrative example, we consider a charged massless complex scalar coupled to U(1) gauge theory in $\mathbb {R}^{1,3}\times {\mathbb {S}}^1$ and discuss the effect of background gauge potential along a compact direction. The electric field produces the charged KK particle nonperturbatively, which we call the KK Schwinger effect. We quantitatively show that KK modes can be produced even when the electric field energy is far below the KK scale. The mechanism is rather general and similar phenomena would occur in any compactification models when a gauge potential along a compact direction evolves in time and experiences a large enough field excursion. We also discuss the subtlety of 4D effective theory truncated by KK modes at an initial time, when the electric field is turned on.