Energy Applications Research Articles

Numerical investigation for bioconvection flow of radiative viscoelastic nanofluid with triple diffusion and higher-order slip effects in a porous medium

Owing to enhanced thermal features, the study of nanofluids has become motivating research area which include various applications in renewable energy, thermal management devices, heat exchangers, microelectronics cooling, automotive industry etc. Owing such applications in mind, the aim of current investigation is to present a triple diffusion flow of viscoelastic nanofluid in presence of higher order slip effects. The problem investigates the insight of thermo-diffusion phenomenon with visualization of heat transfer, solutal concentration, nanoparticles concentration and bioconvection applications. The radiative impact with nonlinear relations and heat source are incorporated in the heat equation. The numerical simulations of problem have been performed via shooting scheme. Various applications are claimed with variation of flow parameters. It has been observed that the increase of the slip parameter enhances both the temperature nanofluid and concentration profiles. The solutal concentration profile increases due to Dufour Lewis number. Moreover, the change in nano-Lewis number leads to a decrease of concentration profile.

Integrating dye-sensitized solar cells and supercapacitors: portable powerpacks for future energy applications

Integrating dye-sensitized solar cells and supercapacitors: portable powerpacks for future energy applications

Precise Synthesis of Single‐Atom Catalysts for Boosting Next‐Generation Advanced Oxidation and Reduction Processes in Sustainable Energy Applications

AbstractSingle‐atom catalysts (SACs) demonstrate high selectivity, maximal atom utilization, and unique active site configurations, establishing them as a rapidly expanding research field. Understanding the intrinsic relationship between structure and catalytic performance is crucial for the effective use of SACs in catalysis. However, providing a clear explanation of the coordination environment and intrinsic structural regulation of SACs remains a significant challenge for next‐generation renewable energy materials, especially in advanced oxidation and reduction processes critical for sustainable energy applications. This comprehensive review offers an in‐depth overview of the current progress and design of SACs, with a specific focus on precise synthesis, structural control, and the relationship between structure and performance. Furthermore, we elucidate the reaction mechanisms of various catalytic systems and the selective methods used to precisely synthesize and enhance catalytic reactions in the sustainable energy sector. Finally, this review explores the complex challenges in investigating and developing SACs and offers a perspective on solutions in advanced oxidation and reduction technologies for future research to overcome these challenges and achieve practical applications.

The influence mechanism of mechanical modification on fly ash carbonation to solidify heavy metals

Dry and wet milling, were selected to carry out modification experiments. The influence of mechanical modification pretreatment on fly ash carbonation to solidify heavy metals was explored, and its influence mechanism was revealed. Mechanical modification can improve the physical properties, and the continuous application of mechanical energy can activate the active sites which strengthen fly ash carbonation. The carbonation efficiency was obtained by 500–800 °C thermogravimetric analysis before and after carbonation. The average carbonation efficiency improved by dry milling is 2.28 %, and that improved by wet milling is 8.11 %. Carbonation has a good curing effect on Cr, Cd, Pb and As, especially when the CO2 is raised to supercritical. At 8 MPa pressure, the leaching concentrations of Cr, Cd, Pb and As decrease by 34.94 %, 7.00 %, 15.28 % and 35.85 %. The stabilization effect of fly ash carbonation on heavy metals is significantly improved after mechanical modification pretreatment. Comparison experiments on characterization of fly ash before and after mechanical modification shows that ball milling significantly increases the specific surface area. The crushing effect of wet milling is better, because the presence of water weakens the agglomeration of fine particles caused by van der Waal force. Mechanical modification can effectively improve the pore structure of fly ash and activate active sites which promote carbonation to form a larger physical wrapping area and strengthen stable carbonate formation. so mechanical modification effectively improves the solidification of heavy metals by carbonation.

Pd-W18O49 Nanowire MEMS Gas Sensor for Ultraselective Dual Detection of Hydrogen and Ammonia.

Demand for real-time detection of hydrogen and ammonia, clean energy carriers, in a sensitive and selective manner, is growing rapidly for energy, industrial, and medical applications. Nevertheless, their selective detection still remains a challenge and requires the utilization of diverse sensors, hampering the miniaturization of sensor modules. Herein, a practical approach via material design and facile temperature modulation for dual selectivity is proposed. A Pd nanoparticles-decorated W18O49 nanowire gas sensor is prepared for dual detection of hydrogen and ammonia. The sensor exhibits distinct operating temperatures for ultraselective detection of hydrogen (125°C) and ammonia (225°C), with high responses of 35.3 and 133.8, respectively. This dual selectivity with high sensitivity is attributed to enhanced oxygen adsorption, the chemical affinity of sensing materials for target gases, and distinct reactivity profiles of gases. The proposed sensor is further integrated into a microelectromechanical system, enabling its small size, low power consumption, and rapid temperature modulation. Moreover, the practical feasibility of this sensor platform for smart energy monitoring systems is demonstrated by assessing its sensing properties in electrochemical ammonia oxidation reaction systems. This work can provide a practical approach for developing a single gas sensor with multiple functionalities for application in electronic nose systems.

Enhanced Grain Boundary Resistance Resulting in High Permittivity and Low Dielectric Loss in CaCu3Ti4O12/LaNiO3

Abstract (1-X) CaCu3Ti4O12 + (X) LaNiO3 composite ceramics were fabricated using pre-reacted calcium copper titanate CaCu3Ti4O12 (CCTO) and lanthanum nickelate LaNiO3 (LNO) and their crystallographic structure and morphology were studied to measure dielectric, impedance, and conductivity values. X-ray diffraction peaks show that CCTO/LNO composites are in a cubic structure. Scanning electron microscopy images show denser and more uniform grains with thin grain boundaries and a smaller average grain size. The permittivity of CCTO is stable in the range 102 -106 Hz, but the composites show huge progress in permittivity by space charge polarization and relaxation in the range 103 -104 Hz, demonstrating improved dielectric properties. The 0.98(CaCu3Ti4O12)+0.02(LaNiO3) sample showed a dielectric constant of 2.58×104 at 1 kHz , which is superior to pure CCTO (2.28×104 at 1 kHz). The electrical behaviour of the metallic filler on the composites was investigated using impedance spectroscopy analysis. The resistance of grain boundary increases with LNO. Activation energies were found to be 0.92, 0.95, and 0.90 eV for x=0.1, 0.2, and 0.3, respectively, and these values are better than that of pristine CCTO (0.85 eV) sample. These results indicate that the prepared CCTO/LNO samples could be useul for high energy applications.

Assessment of the use of biochar from the slow pyrolysis of walnut and almond shells as an energy carrier

ABSTRACT This study explores the energy applications and combustion kinetics of biochar produced from walnut and almond shells through pyrolysis. Using macro-thermogravimetric analysis at heating rates of 10, 15, and 20 K min−1, a multi-step mechanism involving two parallel reactions was used to model thermal decomposition. Bioenergy indices revealed that walnut shell-based biochar (WSB) produced at 773 K and 873 K displayed superior biofuel potential due to its high energy density and low ash content, while almond shell-based biochar (ASB) at 673 K demonstrated the best overall bioenergy performance. Among the tested heating rates, 15 K min−1 provided optimal results for ignition, combustion, and burnout indices, with WSB showing the highest overall combustion performance. Kinetic analysis using the Coats-Redfern method demonstrated the highest R2 values and minimized RMSE and SSE. The activation energy for the first pseudo-component ranged from 54.91 to 129.84 kJ mol−1 for ASB and from 61.71 to 141.85 kJ mol−1 for WSB. For the second pseudo-component, the activation energy ranged from 25.21 to 159.32 kJ mol−1 for ASB and 25.63 to 96.25 kJ mol−1 for WSB. These findings emphasize the potential of WSB and ASB biochar for bioenergy applications, with WSB exhibiting the best combustion characteristics.

A Comprehensive Review of Remaining Useful Life Estimation Approaches for Rotating Machinery

This review paper comprehensively analyzes the prognosis of rotating machines (RMs), focusing on mechanical-flaw and remaining-useful-life (RUL) estimation in industrial and renewable energy applications. It introduces common mechanical faults in rotating machinery, their causes, and their potential impacts on RM performance and longevity, particularly in wind, wave, and tidal energy systems, where reliability is crucial. The study outlines the primary procedures for RUL estimation, including data acquisition, health indicator (HI) construction, failure threshold (FT) determination, RUL estimation approaches, and evaluation metrics, through a detailed review of published work from the past six years. A detailed investigation of HI design using mechanical-signal-based, model-based, and artificial intelligence (AI)-based techniques is presented, emphasizing their relevance to condition monitoring and fault detection in offshore and hybrid renewable energy systems. The paper thoroughly explores the use of physics-based, data-driven, and hybrid models for prognosis. Additionally, the review delves into the application of advanced methods such as transfer learning and physics-informed neural networks for RUL estimation. The advantages and disadvantages of each method are discussed in detail, providing a foundation for optimizing condition-monitoring strategies. Finally, the paper identifies open challenges in prognostics of RMs and concludes with critical suggestions for future research to enhance the reliability of these technologies.

Data-Driven Remaining Useful Life Estimation

This paper explores the development and application of data-driven prognostic models for estimating the Remaining Useful Life (RUL) of Nuclear Power Plant (NPP) condensers experiencing tube fouling. Due to the unavailability of run-to-failure industry sensor data, we utilized simulated data generated by the Asherah Nuclear Power Plant Simulator (ANS), initially designed by the International Atomic Energy Agency (IAEA) and programmed in Simulink for cyber security simulations. ANS's adaptability allows it to simulate Pressurized Water Reactor (PWR) behaviors given a time series of operating conditions and to introduce degradation modules to mimic fouling effects. Our study compares two primary approaches applied to data generated by ANS: inference-based and direct prediction methods. The selected inference-based approach estimates the health state of the condenser using a pipeline formed by an Auto Associative Kernel Regressor and a Hidden Markov Model (HMM), which subsequently combines the state estimates with its parameters to predict the RUL. The direct prediction method employs a Gradient Boosting Regressor Decision Tree (GBRDT) to map input variables directly to RUL. Our findings demonstrate the efficacy and limitations of each method through the case study, providing valuable insights for the adoption of data-driven RUL estimation techniques in industrial and energy applications.

Temperature and Pressure Effects on Phase Transitions and Structural Stability in CsPb2Br5 and CsPb2Br4I Perovskite-Derived Halides.

All-inorganic perovskites exhibit outstanding light absorption properties in the visible range suitable for solar energy applications. We focus on the synthesis of CsPb2(Br,I)5 using mechanochemical procedures. Synchrotron X-ray diffraction (SXRD) data are essential for determining the crystallographic evolution in the 295-753 K temperature range. From room temperature to 573 K, the crystal structure is refined in a two-dimensional (2D) tetragonal framework (space group: I4/mcm) consisting of layers of face sharing [Pb(Br,I)8] polyhedra. Above a transition temperature of Tt = 630 and 621 K, identified from differential scanning calorimetry (DSC) curves for CsPb2Br5 and CsPb2Br4I, respectively, a cubic three-dimensional (3D) corner-sharing perovskite structure is identified, showing substantial Cs and (Br,I) deficiency. A more ionic character for Cs-halide versus Pb-halide is derived from the evolution of the anisotropic atomic displacements. An ultralow thermal conductivity of 0.35-0.18 W m-1 K-1 is related to the low Debye temperatures. From high-pressure SXRD studies, the change in B0 can be attributed to a basic expansion of the unit-cell volume caused by the chemical pressure from iodine within the CsPb2Br5 framework. UV-vis-NIR spectroscopy revealed optical gaps of approximately 2.93 and 2.50 eV, respectively, which agrees with ab initio calculations.

Non-Adiabatic Excited-State Time-Dependent GW (TDGW) Molecular Dynamics Simulation of Nickel-Atom Aided Photolysis of Methane to Produce a Hydrogen Molecule

Methane photolysis is a very important initiation reaction from the perspective of hydrogen production for alternative energy applications. In our recent work, we demonstrated using our recently developed novel method, non-adiabatic excited-state time-dependent GW (TDGW) molecular dynamics (MD), how the decomposition reaction of methane into a methyl radical and a hydrogen atom was captured accurately via the time-tracing of all quasiparticle levels. However, this process requires a large amount of photoabsorption energy (PAE ∼10.2 eV). Moreover, only one hydrogen atom is produced via a single photon absorption. Transition metal atoms can be used as agents for photochemical reactions, to reduce this optical gap and facilitate an easier pathway for hydrogen production. Here, we explore the photolysis of methane in the presence of a Ni atom by employing TDGW-MD. We show two possibilities for hydrogen-atom ejection with respect to the location of the Ni atom, towards the Ni side or away from it. We demonstrate that only the H ejection away from the Ni side facilitates the formation of a hydrogen molecule with the quasiparticle level corresponding to it having an energy close to the negative ionization potential of an isolated H2 molecule. This is achieved at a PAE of 8.4 eV which is lower compared to that of pristine methane. The results obtained in this work are an encouraging step towards transition metal-mediated hydrogen production via photolysis of hydrocarbons.

Hydrogen in Burners: Economic and Environmental Implications

For centuries, fossil fuels have been the primary energy source, but their unchecked use has led to significant environmental and economic challenges that now shape the global energy landscape. The combustion of these fuels releases greenhouse gases, which are critical contributors to the acceleration of climate change, resulting in severe consequences for both the environment and human health. Therefore, this article examines the potential of hydrogen as a sustainable alternative energy source capable of mitigating these climate impacts. It explores the properties of hydrogen, with particular emphasis on its application in industrial burners and furnaces, underscoring its clean combustion and high energy density in comparison to fossil fuels, and also examines hydrogen production through thermochemical and electrochemical methods, covering green, gray, blue, and turquoise pathways. It discusses storage and transportation challenges, highlighting methods like compression, liquefaction, chemical carriers (e.g., ammonia), and transport via pipelines and vehicles. Hydrogen combustion mechanisms and optimized burner and furnace designs are explored, along with the environmental benefits of lower emissions, contrasted with economic concerns like production and infrastructure costs. Additionally, industrial and energy applications, safety concerns, and the challenges of large-scale adoption are addressed, presenting hydrogen as a promising yet complex alternative to fossil fuels.

Active Photonic Glass for Hydrogen Generation.

Chirality is vital in many living species since it is responsible for structural iridescent coloration and plays a key role in light harvesting during natural photosynthesis. Developing photoactive materials with such chiral structures is a challenging but promising strategy for energy applications. Here, we describe a straightforward method to establish an active photonic glass obtained through the co-condensation oftetramethyl orthosilicate (TMOS) and titanium diisopropoxide bis(acetylacetonate) (TAA) dissolved in a liquid crystal formed from cellulose nanocrystalline (CNC). The inorganic glass maintains a long range of chiral nematic ordering, displaying iridescent colors characterized by a Bragg peak reflection. The reflected wavelengths are tuned all over the UV-visible range, demonstrating that the replica of the chiral nematic structure generates photonic properties. Incorporation of gold nanoparticles (Au NPs) into the films is further performed by impregnation/chemical reduction. We show that the charge carrier density and photocatalytic H2 generation were amplified when the photonic band gap edges matched the absorbance of the TiO2 and localized surface plasmon resonance (LSPR) of AuNPs. This photocatalytic glass with chiral nematic ordering and a tunable photonic bandgap paves the way for the development of metamaterials with new applications, such as asymmetric photocatalysis.

Performance of Single Nanopore and Multi-Pore Membranes for Blue Energy.

The salinity gradient power extracted from the mixing of electrolyte solutions at different concentrations through selective nanoporous membranes is a promising route to renewable energy. However, several challenges need to be addressed to make this technology profitable, one of the most relevant being the increase of the extractable power per membrane area. Here, the performance of asymmetric conical and bullet-shaped nanopores in a 50 nm thick membrane are studied via electrohydrodynamic simulations, varying the pore radius, curvature, and surface charge. The output power reaches ~60 pW per pore for positively charged membranes (surface charge σw=160 mC/m2) and ~30 pW for negatively charges ones, σw=-160 mC/m2 and it is robust to minor variations of nanopore shape and radius. A theoretical argument that takes into account the interaction among neighbour pores allows to extrapolate the single-pore performance to multi-pore membranes showing that power densities from tens to hundreds of W/m2 can be reached by proper tuning of the nanopore number density and the boundary layer thickness. Our model for scaling single-pore performance to multi-pore membrane can be applied also to experimental data providing a simple tool to effectively compare different nanopore membranes in blue energy applications.

Enhanced High‐Gain Switched Capacitor DC–DC Converter Optimizing Renewable Energy Integration

ABSTRACTA novel high‐gain switched capacitor (HGSC) DC–DC converter for carbon neutral energy applications is presented in the scientific paper. It consists of two MOSFET switches, and utilization of a simultaneous switching approach for the switches enables simplified control. The switched capacitor (SC) technique is utilized to extract high gain from the proposed HGSC topology; the basic idea is periodic charging and discharging of the capacitor. The proposed HGSC topology operational mode is carried out in Continuous Conduction Mode (CCM) along with the steady‐state analysis, and different switching stages are discussed in detail. Then, an analysis is carried out to demonstrate the proposed HGSC converter's special feature with other high‐gain converters. An averaging state‐space technique is used to determine the suggested converter's dynamics performance, and a small signal analysis is used to verify its stability. Furthermore, the HGSC topology is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, nonidealities voltage gain is derived. The maximum efficiency of 96.7% is obtained at 150 W output power with the help of the dSPACE 1104 controller. Whenever the HGSC converter is fed with an input voltage supply of 20 V. It generates output voltages between 140 and 240 V. Extensive experimental investigation is carried out on a 200 W laboratory prototype model to verify the practicability and feasibility of HGSC DC–DC converter topology.

Thermal kinetic analysis and characterization of water hyacinth biomass for renewable energy application

Thermal kinetic analysis and characterization of water hyacinth biomass for renewable energy application

Microwave aided synthesis of samarium hafnate pyrochlore-sulphur doped reduced graphene oxide for electrochemical detection of bendiocarb

The current study reports the synthesis of pyrochlore type Sm2Hf2O7 (SHO) and its nanocomposite with sulfur-doped reduced graphene oxide (SR). SHO/SR nanocomposite was synthesized using a simple hydrothermal method followed by a microwave-aided synthetic method. Morphological investigations indicate that long SHO particles are well-aggregated in the wrinkled two-dimensional SR. Modified the glassy carbon electrodes (GCE) using SHO, SR and SHO/SR and evaluated for the electrochemical detection of an insecticide, bendiocarb (BDC). Enhanced electrochemical performance was observed in SHO/SR@GCE compared to SHO and SR. Superior electrochemical performance in SHO/SR could be attributed to enhanced conductivity, surface area and stability. Differential pulse voltammetry (DPV) technique showed good sensitivity, and the observed range is 0.05 to 300 μM with a 0.671 μM limit of detection (LOD). In addition, DPV technique is used for the detection of BDC in tomatoes and cabbage, finding a good percentage recovery (97.12 to 99.47 %) with less than 2.65 % relative standard deviation (RSD). The stability of the SHO/SR@GCE was good, and the current response retention was found to be 88.6 ± 1.93 % even after twenty days. SHO/SR's versatile structure, stability, conductivity, and surface area make it an ideal material for developing pyrochlore-based materials for electrochemical and energy applications.

Numerical simulation of micro gas turbine engine based on time-marching one-dimensional method

The advancement of gas turbine technology serves as a crucial indicator of high-tech and technological prowess, with widespread applications in aviation, marine vessels, power generation, and clean energy. The precision of the performance simulation model stands as a pivotal component in the development of gas turbines. The present study deals with the one-dimensional modeling and validation of gas turbines by utilizing a time-marching scheme, in order to establish the correlation between the engine components and full-engine performance. The flow through the turbomachinery was solved by the one-dimensional model. The combustor was modelled as a compressible actuator disk. The accuracy of the turbomachinery solver was validated using the KJ66 compressor and turbine, and the predicted results demonstrated consistency with the experimental data or the three-dimensional simulations. The characteristic interface method was developed based on Riemann invariants, in order to provide the flow properties on both sides of the combustor. The results indicated that compared to the component-by-component approach, the developed characteristic interface method significantly reduced the computational time. Finally, the developed one-dimensional method was employed to simulate the performance of the KJ66 micro gas turbine engine. The predicted performance for the KJ66 gas turbine engine was consistent with the trend in the experiment results. The novelty of the present study was its modeling approach, and its ability to eliminate the dependence on the general component map, and obtain meridional distributions of flow parameters, which cannot be achieved in traditional zero-dimensional thermal cycle calculations. These results can provide an accurate and powerful tool for the analysis and optimization of component and full-engine performance in the preliminary design stage.

Combinatorial synthesis of AlNi alloys by low-pressure cold spray deposition and post-laser alloying process

Aluminum-Nickel (AlNi) alloys are of great interest due to their exceptional high-temperature wear and corrosion resistance, making them valuable in transport, energy, and materials processing applications. However, challenges in the production and shaping of these alloys, particularly as thick coatings, remain significant. This study introduces an innovative method for the high-throughput synthesis of AlNi coatings, utilizing a two-step process: low-pressure cold spray deposition followed by laser surface alloying. The combination of these two techniques not only improves the synthesis process but also opens avenues for exploring new material compositions with specific application requirements. This approach holds significant potential for accelerating the development and optimization of advanced coatings and multiphase compounds in applications such as repair and additive manufacturing.Aluminum and nickel powders were co-sprayed to create coatings with controlled compositions ranging from 50Al50Ni to 10Al90Ni (wt%). Subsequent laser treatment induced in-situ alloying and homogenization, resulting in dense, uniform AlNi coatings. The microstructure and chemical composition were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), while X-ray Diffraction (XRD) identified the formation of various phases, including Al3Ni and AlNi3 phases. The process demonstrated effective alloying and microstructural homogeneity, with residual alumina present at the surface. Despite the presence of some microstructural defects, such as cracking, this method provides a robust foundation for further refinement and opens new possibilities for tailoring alloy properties through combinatorial cold spray and laser alloying techniques.

Promising transition metal molybdate (TMM) single phase microstructures for asymmetric supercapacitor and photocatalytic applications

The increasing impact of worldwide energy challenges has sparked significant interest in developing multifunctional nanomaterials for energy and environmental applications. Among semiconductor photocatalysts, stable mixed metal molybdate materials have garnered much interest regarding energy storage and photocatalytic dye degradation. In this context, we have synthesized three different single-phase metal molybdates (NiMoO4, MnMoO4, and Fe2(MoO4)3) using the gel matrix method. XRD and Raman were executed to confirm phase formation of the acquired materials. Difference in surface morphology of synthesized transition metal molybdate powders was examined using SEM analysis. The energy-storing properties of synthesized transition metal molybdate powders were analyzed and compared using three and two electrode method. At a 1 Ag-1 current density, the as-synthesized NiMoO4, MnMoO4, and Fe2(MoO4)3 nanostructures exhibit specific capacitances of about 424.6, 325.5 and 157.8 Fg-1, respectively. Furthermore, the fabricated ASC device with NiMoO4 shows 41.6 Whkg-1 and 750 Wkg-1 as maximum energy and power density at 1 Ag-1, respectively. Meanwhile, photocatalytic methylene blue degradation was carried out using the as-synthesized materials as photocatalysts. The Fe2(MoO4)3 effectively decolourizes the dye with a maximum efficiency of 82.7 %, when compared to other two metal molybdate powders. Thus, the results show that the synthesized metal molybdates such as NiMoO4, and Fe2(MoO4)3 can act as potent electrode materials and efficient photocatalysts for energy storage and dye degradation applications when compared to MnMoO4.