Search Results (51)

Reliable performance of TRISO (tristructural isotropic) nuclear fuel depends on the interplay between its multilayer architecture and the buffer-layer microstructure, which are difficult to isolate experimentally. We implement a multiscale, multiphysics model in the open-source MOOSE (Multiphysics Object-Oriented Simulation Environment) framework that couples particle-scale thermo-mechanical finite-element analysis with mesoscale phase-field fracture to link microstructure to effective stiffness and strength. The model resolves the combined influence of pore volume fraction, size, and aspect ratio and explicitly separates the effects of reduced load-bearing capacity from stress concentrations in the porous buffer. Simulations reveal substantial hoop stresses across coating layers under nominal thermal conditions due to material property mismatches and temperature gradients. In the buffer, stiffness and strength decrease with porosity; morphology is decisive: as aspect ratio decreases, strength degrades far more rapidly than stiffness, consistent with crack-like pores that amplify local stresses. The framework reproduces logarithmic trends with aspect ratio and explains the higher sensitivity of strength, providing parameters that can inform design and acceptance criteria (e.g., limits on pore elongation and porosity gradients). Implemented within MOOSE, the approach is readily extensible to irradiation-dependent kinetics, interface debonding, and uncertainty-quantified 3D analyses to support risk-informed TRISO fuel development. Full article

Co₃O₄ nanoparticles synthesized by solution combustion synthesis present a versatile platform for the development of porous nanostructures with tunable morphology and physicochemical properties. Synthesis conditions and parameters such as fuel type; fuel-to-oxidizer ratio and temperature control lead yielding; and Co₃O₄ NPs with fine particle size, surface area, and porosity result in enhancing their electrochemical and catalytic capabilities. This review evaluates present studies about SCS Co₃O₄ NPs to study how synthesis parameter modifications affect both surface morphology and material structure characteristics including porosity features, which make their improved performance ideal for lithium-ion batteries and supercapacitors. Moreover, the integration of dopants with carbon-based hybrid composites enhances material conductivity and stability by addressing both capacity fading and low electronic conductivity concerns. This review mainly aims to explore the significant relation between fundamental material design principles together with practical uses and provides predictions about future research advancements that aim to enhance the performance of Co₃O₄ NPs in next-generation energy and environmental technology applications. Full article

This article compares two new textile materials used to clean up spills of oil or two oil products (crude oil, diesel fuel, and base oil SN 150). The plain-woven cotton fabric is hydrophilic, with a typical porous structure. After coating with a layer of chitosan modified with benzaldehyde and cross-linked with glutaraldehyde (CB), its hydrophobicity increases, hence the sorption affinity to hydrophobic hydrocarbons. Including in situ synthesized zinc oxide particles in the hydrophobic chitosan layer (CBZ) changes its structure and increases the sorption capacity. The morphology of the layers was assessed using scanning electron microscopy (SEM) and by comparing the contact angles of the pollutants against the cotton fabric and the composite materials. EDX analysis and mapping for the Zn element show that zinc is homogeneously distributed on the fabric surface. The roughness enhancement and mesoporous structure under the influence of zinc oxide particles were established by the Brunauer Emmett Teller (BET) method and atomic force microscopy (AFM). The advantages of textile composites are their flexibility, stability, and ability to float on the water and wipe up oil spills. It was found that the materials can be successfully regenerated and used repeatedly, making them highly effective because the sorbed crude oil or petroleum products can be separated and utilized. Full article

Carbon dioxide (CO₂), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO₂ capture and storage technologies is of significant importance for the future of planet Earth due to atmospheric, climate, and environmental concerns. A cleaner and more sustainable approach to CO₂ capture and storage using porous materials, membranes, and amine-based sorbents could offer excellent possibilities. Here, sucrose-derived porous carbon particles (PCPs) were synthesized as adsorbents for CO₂ capture. Next, these PCPs were modified with branched- and linear-polyethyleneimine (B-PEI and L-PEI) as B-PEI-PCP and L-PEI-PCP, respectively. These PCPs and their PEI-modified forms were then used to prepare metal nanoparticles such as Co, Cu, and Ni in situ as M@PCP and M@L/B-PEI-PCP (M: Ni, Co, and Cu). The presence of PEI on the PCP surface enables new amine functional groups, known for high CO₂ capture ability. The presence of metal nanoparticles in the structure may be used as a catalyst to convert the captured CO₂ into useful products, e.g., fuels or other chemical compounds, at high temperatures. It was found that B-PEI-PCP has a larger surface area and higher CO₂ capture capacity with a surface area of 32.84 m²/g and a CO₂ capture capacity of 1.05 mmol CO₂/g adsorbent compared to L-PEI-PCP. Amongst metal-nanoparticle-embedded PEI-PCPs (M@PEI-PCPs, M: Ni, Co, Cu), Ni@L-PEI-PCP was found to have higher CO₂ capture capacity, 0.81 mmol CO₂/g adsorbent, and a surface area of 225 m²/g. These data are significant as they will steer future studies for the conversion of captured CO₂ into useful fuels/chemicals. Full article

Nowadays, two of the biggest obstacles restricting the further development of methanol fuel cells are excessive cost and insufficient catalytic activity of platinum-based catalysts. Herein, platinum nanoparticle supported graphene aerogel (Pt/3DGA) was successfully synthesized by a one-step hydrothermal self-assembly method. The loose three-dimensional structure of the aerogel is stabilized by a simple one-step method, which not only reduces cost compared to the freeze-drying technology, but also optimizes the loading method of nanoparticles. The prepared Pt/3DGA catalyst has a three-dimensional porous structure with a highly cross-linked, large specific surface area, even dispersion of Pt NPs and good electrical conductivity. It is worth noting that its catalytic activity is 438.4 mA/mg with long-term stability, which is consistent with the projected benefits of anodic catalytic systems in methanol fuel cells.. Our study provides an applicable method for synthesizing nano metal particles/graphene-based composites. Full article

A Computational Fluid Dynamic study was carried out to match the measured outer ash deposition rates associated with the combustion of petroleum coke (PC)–natural gas in AIR and O₂/CO₂ (70/30 vol%, OXY70). The fly ash PSD associated with high-fixed-carbon, non-porous fuel was estimated using a shrinking sphere burnout model and employed in conjunction with particle kinetic energy (PKE), particle viscosity (µ_P), and a critical Weber-number-based capture criterion. Deposition rate predictions were sensitive to the fly ash composition employed for estimating µ_P due to the significant enrichment of Fe in the deposits. Predictions were insensitive to the specific µ_P model formulation employed or whether the V₂O₅ in the ash was assumed to play the role of a glass former or a glass modifier. OXY70 scenario impaction rates were significantly lower than the measured deposition rates when the fly ash PSD associated with the AIR scenario was employed in the calculations. This necessitated an ad hoc modification of the OXY70 fly ash PSD to a coarser range to match the measurements and attributing it to agglomeration resulting from longer residence times and higher temperatures. This shift in PSD was in line with AIR and OXY70 fly ash PSD measurements reported previously. Full article

We studied the influence of the ethylenediaminetetraacetic acid (EDTA) content used as combustion fuel when fabricating nickel oxide (NiO) nanocatalysts via solution combustion synthesis, as well as the growth behavior of carbon nanotubes (CNTs) using this catalyst. Nickel nitrate hexahydrate (Ni(NO₃)₂∙6H₂O) was used as the metal precursor (an oxidizer), and the catalysts were synthesized by adjusting the molar ratio of fuel (EDTA) to oxidizer in the range of 1:0.25 to 2.0. The results of the crystal structure analysis showed that as the EDTA content increased beyond the chemical stoichiometric balance with Ni(NO₃)₂∙6H₂O (F/O = 0.25), the proportion of Ni metal within the catalyst particles decreased, and only single-phase NiO was observed. Among the synthesized catalysts, the smallest crystallite size was observed with a 1:1 ratio of Ni ions to EDTA. However, an increase in the amount of EDTA resulted in excessive fuel supply, leading to an increase in crystallite size. Microstructure analysis revealed porous NiO agglomerates due to the use of EDTA, and differences in particle growth based on the fuel ratio were observed. We analyzed the growth behavior of CNTs grown using NiO nanocatalysts through catalytic chemical vapor deposition (CCVD). As the F/O ratio increased, it was observed that the catalyst particles grew excessively beyond hundreds of nanometers, preventing further CNT growth and leading to a rapid termination of CNT growth. Raman spectroscopy was used to analyze the structural characteristics of CNTs, and it was found that the I_D/I_G ratio indicated the highest CNT crystallinity near an F/O ratio of 1:1. Full article

Supported ozone catalysts usually take alumina, activated carbon, mesoporous molecular sieve, graphene, etc. as the carrier for loading metal oxide via the impregnation method, sol–gel method and precipitation method. In this work, a Mn-modified fly ash catalyst was synthesized to reduce the consumption and high unit price of traditional catalyst carriers like alumina. As a solid waste discharged from coal-fired power plants fueled by coal, fly ash also has porous spherical fine particles with constant surface area and activity, abd is expected to be applied as the main component in the synthesis of ozone catalyst. After the pretreatment process and modification with MnOx, the obtained Mn-modified fly ash exhibited stronger specific surface area and porosity combined with considerable ozone catalytic performance. We used sodium acetate as the contaminant probe, which is difficult to directly decompose with ozone as the end product of ozone oxidation, to evaluate the performance of this Mn-modified fly. It was found that ozone molecules can be transformed to generate ·OH, ·O₂⁻ and ¹O₂ for the further oxidation of sodium acetate. The oxygen vacancy produced via Mn modification plays a crucial role in the adsorption and excitation of ozone. This work demonstrates that fly ash, as an industrial waste, can be synthesized as a potential industrial catalyst with stable physical and chemical properties, a simple preparation method and low costs. Full article

An investigation on the dispersal characteristics of the cylindrically packed material of dry powder particles driven by explosive load is presented. By establishing a controllable experimental system under laboratory conditions and combining with near-field simulation, the particle dispersal process is described. Additionally, Kelvin–Helmholtz instability is observed during the process of jet deceleration dispersal. The characteristic parameters of radially propagated particles are explored under different mass ratio of particle-to-charge (M/C). Results indicate that, when the charge mass remains constant, an increase in M/C leads to a decrease in dispersed jet number, void radius and maximum velocity, wherein the maximum velocity correlates with calculations by the porous Gurney model. The case of the smaller M/C always has a higher outer-boundary radius and area expansion factor. Findings indicate that when particles detach from the jet upon reaching minimum acceleration and entering low-speed far-field stage from high-speed near-field stage, the outer-boundary radius is 30~36 times the initial particles’ body radius under different M/C. In addition, particle concentration distribution over time and distance is qualitatively analyzed by the grayscale image method. This research can be referential for improving the fire-extinguishing capacity of extinguishing bombs and the damage property of fuel air explosive (FAE). Full article

Photocatalytic CO₂ reduction to valuable hydrocarbon solar fuel is of great significance but still challenging. Strong CO₂ enrichment ability and easily adjustable structures make metal-organic frameworks (MOFs) potential photocatalysts for CO₂ conversion. Even though pure MOFs have the potential for photoreduction of CO₂, the efficiency is still quite low due to rapid photogenerated electron–hole recombination and other drawbacks. In this work, graphene quantum dots (GQDs) were in situ encapsulated into highly stable MOFs via a solvothermal method for this challenging task. The GQDs@PCN-222 with encapsulated GQDs showed similar Powder X-ray Diffraction (PXRD) patterns to PCN-222, indicating the retained structure. The porous structure was also retained with a Brunauer–Emmett–Teller (BET) surface area of 2066 m²/g. After incorporation of GQDs, the shape of GQDs@PCN-222 particles remained, as revealed by the scanning electron microscope (SEM). As most of the GQDs were covered by thick PCN-222, it was hard to observe those GQDs using a transmission electron microscope (TEM) and a high-resolution transmission electron microscope (HRTEM) directly, the treatment of digested GQDs@PCN-222 particles by immersion in a 1 mM aqueous KOH solution can make the incorporated GQDs visible in TEM and HRTEM. The linker, deep purple porphyrins, make MOFs a highly visible light harvester up to 800 nm. The introduction of GQDs inside PCN-222 can effectively promote the spatial separation of the photogenerated electron–hole pairs during the photocatalytic process, which was proved by the transient photocurrent plot and photoluminescence emission spectra. Compared with pure PCN-222, the obtained GQDs@PCN-222 displayed dramatically enhanced CO production derived from CO₂ photoreduction with 147.8 μmol/g/h in a 10 h period under visible light irradiation with triethanolamine (TEOA) as a sacrificial agent. This study demonstrated that the combination of GQDs and high light absorption MOFs provides a new platform for photocatalytic CO₂ reduction. Full article

Heat storage in systems integrated with renewable energy sources in facilities can reduce the consumption of fossil fuels, cut maintenance costs, and decrease greenhouse gas emissions from buildings and other objects. One of the possible solutions is the use of a stone heat accumulator for short-term heat storage and the use of this deposit in the ventilation process of the facility. During short-term air flow through the porous material from which an accumulator bed is made, there is an exchange of heat and mass between the flowing air and the bed particles. In the long term, the use of an accumulator can lead to an increase in dust and the development of pathogenic microorganisms, endangering human life and health. Therefore, understanding the factors influencing the efficient use of a stone deposit is very important. The aim of this study is to calculate the changes in thermal-mass parameters in the air flowing out of the stone accumulator and to assess the effect of long-term stone accumulator use on the content of microorganisms and dust concentration in bioaerosol. The application of the heat storage system in the stone bed leads to the formation of strictly controlled microclimatic conditions, and the tested air does not constitute a threat to the people staying in the object. The concentration standards of PM10 and PM2.5 exceeded the limit values (PM2.5 = 20 μg∙m⁻³ and PM10 = 40 μg∙m⁻³), and, thus, the air in the studied greenhouse was classified as polluted. The analysis also showed that, for the analyzed conditions, a 20% increase in the initial temperature of the accumulator bed results in a nearly 20% increase in the outlet air temperature. Full article

Fly ash from coal represents the foremost waste product of fossil fuel combustion. These waste materials are most widely utilised in the cement and concrete industries, but the extent of their use is insufficient. This study investigated the physical, mineralogical, and morphological characteristics of non-treated and mechanically activated fly ash. The possibility of enhancing the hydration rate of the fresh cement paste by replacing part of the cement with non-treated and mechanically activated fly ash, and the hardened cement paste’s structure and early compressive strength performance, were evaluated. At the first stage of the study, up to 20% mass of cement was replaced by untreated and mechanically activated fly ash to understand the impact of the mechanical activation on the hydration course; rheological properties, such as spread and setting time; hydration products; mechanical properties; and microstructure of fresh and hardened cement paste. The results show that a higher amount of untreated fly ash significantly prolongs the cement hydration process, decreases hydration temperature, deteriorates the structure and decreases compressive strength. Mechanical activation caused the breakdown of large porous aggregates in fly ash, enhancing the physical properties and reactivity of fly ash particles. Due to increased fineness and pozzolanic activity by up to 15%, mechanically activated fly ash shortens the time of maximum exothermic temperature and increases this temperature by up to 16%. Due to nanosized particles and higher pozzolanic activity, mechanically activated fly ash facilitates a denser structure, improves the contact zone between the cement matrix, and increases compressive strength up to 30%. Full article

The consumption of dietary fibres can affect glycemic power and control diabetes. Sugarcane fibre (SCF) is known as insoluble dietary fibre, the properties of which can be affected by physical, chemical, and enzymatic treatments. In this study, alkaline hydrogen peroxide (AHP) treatments were conducted over time (0.5, 1, 3, and 5 h) at 12.6% (w/v) SCF and the effects on the physicochemical and structural properties of the SCF were evaluated. After making dough and bread with the SCF, with and without AHP treatments, the glycemic responses of the bread samples were evaluated. Shorter durations of AHP treatment (0.5 and 1 h) reduced lignin effectively (37.3 and 40.4%, respectively), whereas AHP treatment at 1 and 3 h duration was more effective in increasing particle sizes (50.9 and 50.1 μm, respectively). The sugar binding capacity, water holding capacity (from 2.98 to 3.86 g water/g SCF), and oil holding capacity (from 2.47 to 3.66 g oil/g SCF) increased in all AHP samples. Results from Fourier-transform infrared spectroscopy (FTIR) confirmed the polymorphism transition of cellulose (cellulose I to cellulose II). The morphology of SCF detected under scanning electron microscopy (SEM) indicated the conversion of the surface to a more porous, rough structure due to the AHP treatment. Adding SCF decreased dough extensibility but increased bread hardness and chewiness. All SCF-incorporated bread samples have reduced glycemic response. Incorporation of 1, 3, and 5 h AHP-treated SCF was effective in reducing the glycemic potency than 0.5 h AHP-treated SCF, but not significantly different from the untreated SCF. Overall, this study aims to valorize biomass as AHP is commonly applied to bagasse to produce value-added chemicals and fuels. Full article

There is tremendous potential for both small- and large-scale applications of low-temperature operational ceramic fuel cells (LT-CFCs), which operate between 350 °C and 550 °C. Unfortunately, the low operating temperature of CFCs was hampered by inadequate oxygen reduction electrocatalysts. In this work, the electrochemical characteristics of a semiconductor heterostructure composite based on WO₃-CaFe₂O₄ deposited over porous Ni-foam are investigated. At low working temperatures of 450–500 °C, the developed WO₃-CaFe₂O₄ pasted on porous Ni–foam heterostructure composite cathode exhibits very low area-specific resistance (0.78 Ω cm²) and high oxygen reduction reaction (ORR) activity. For button-sized SOFCs with H₂ and atmospheric air fuels, we have demonstrated high-power densities of 508 mW cm⁻² running at 550 °C, and even potential operation at 450 °C, using WO₃-CaFe₂O₄ seeded on porous Ni-foam cathode. Moreover, WO₃-CaFe₂O₄ composite heterostructure with Ni foam paste exhibits very low activation energy compared to both WO₃ and CaFe₂O₄ alone, which supports ORR activity. To comprehend the enhanced ORR electrocatalytic activity of WO₃-CaFe₂O₄ pasted on porous Ni-foam heterostructure composite, several spectroscopic tests including X-ray diffraction (XRD), photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS) were used. The findings may also aid in the creation of useful cobalt-free electrocatalysts for LT-SOFCs. Full article

A microporous layer (MPL) is a transition layer with a porous material structure, located between the gas diffusion layer (GDL) and catalyst layer (CL) in a proton exchange membrane fuel cell (PEMFC). It not only significantly improves electron transfer and heat conduction in membrane electrode assembly, but also effectively manages liquid water transport to enhance the fuel cell performance. The MPL is usually coated on one side of the GDL. The fragile nature of MPL makes it challenging to characterize the effective transport properties using experimental methods. In this study, a stochastic numerical method is implemented to reconstruct the three-dimensional microstructure of an MPL consisting of carbon particles and PTFE. The reliability of the MPL reconstructed model is validated using experimental data. The relationship between the effective transport properties and the compression strain is obtained using the Pore Scale Model (PSM), while the relationship between the liquid water saturation and capillary pressure is solved by Lattice Boltzmann Method (LBM). The effective transport properties in the MPL are then imported into the two-phase flow fuel cell model. It is found that the effective transport parameters in MPL obtained by PSM and LBM can improve the accuracy of the model calculation. This study provides an effective method to reconstruct the microstructure of MPL that can generate precise MPL transport parameters for utilization in various PEMFC performance prediction models. Full article