Pore Characteristics Research Articles

The Impact of Pore Geometry on Frictional Properties of hBN and MoS2 Nanomaterials.

Two-dimensional (2D) nanomaterials hold significant promise for reducing energy consumption in water desalination. This study investigates the influence of pore size and shape on the slip behavior of saline water at the interface of two promising 2D nanomaterials: hexagonal boron nitride (hBN) and molybdenum disulfide (MoS2). Slip length, a key parameter governing fluid flow at the nanoscale, is highly dependent on interfacial properties. Here, we explore how the pore characteristics in these 2D nanomaterials can impact slip length, aiming to gain a fundamental understanding of the role of pore size and shape in optimizing desalination efficiency. We performed quantum mechanical calculations to compute the partial atomic charges on atoms in hBN and MoS2 containing pores. Our DFT calculations reveal a spatially varying charge distribution on these 2D nanomaterials with pores, which we then incorporate into molecular dynamic simulations to elucidate their influence on the 2D nanomaterial-water interface. Our results reveal a significant impact of pore size on friction for nanomaterials containing hexagonal pores, while pore size had no effect on nanomaterials containing triangular pores. Moreover, friction increases with pores in both materials. This research contributes to the development of efficient and energy-saving desalination technologies through the manipulation of interfacial properties in 2D nanomaterials.

Pore Characteristics and Thermal Properties of a Binary Eutectic Adsorbed into Modified Waste Navel Orange Peels for Energy Storage

Pore Characteristics and Thermal Properties of a Binary Eutectic Adsorbed into Modified Waste Navel Orange Peels for Energy Storage

Change of morphology of rice derived spherical hydrochar during activation

In many industrial scenarios, not only pore characteristics but also shape or macro morphology of activated carbon (AC) matters. Herein, influence of typical activating reagents (ZnCl2, H3PO4 or K2C2O4) on transformation of spherical hydrochar derived from rice were investigated. Activation of the hydrochar with H3PO4 and ZnCl2 at 550 °C promoted condensation reactions to yield more AC than that in activation with K2C2O4 at 800 °C (70.4 % with ZnCl2 versus 46.7 % with K2C2O4). The specific surface area (SBET) of AC produced with ZnCl2 or K2C2O4 showed similar values (1159.5 versus 1180.3 m2g−1). Nevertheless, the intensive cracking with K2C2O4 formed AC of more mesopores and micropores of larger diameter, facilitating adsorption of phenol (removal rate: 97.6 % versus 85.0 % over AC from ZnCl2). In-situ DRIFTS characterization of the activation indicated that H3PO4 and ZnCl2 catalyzed fast transformation of -OH and CO at < 300 °C via dehydration and condensation but still retained a large portion of H and O in AC. K2C2O4 catalyzed cracking but also retained oxygen-containing species and hindered aromatization. Pyrolysis of the hydrochar at 800 °C released around half of organic matters but did not result in burst of spheres. H3PO4 activated outer surface of hydrochar spheres, forming layered lamella structures via interparticle cross-condensation. ZnCl2 permeated into inner core of spheres and induced condensation inside, showing little effect on spherical morphology. Severe cracking with K2C2O4 led to partial crack of spheric structures and formation of piled particulate matters. Life cycle assessment (LCA) showed that the activation of the hydrochar with ZnCl2 showed the greatest impact on environment.

High-precision digital rock construction and electrical property upscaling in tight sandstone

The lithology and rock physical properties of tight sandstone reservoirs become increasingly complex, resulting in a more challenging reservoir evaluation process. Conventional rock physics experiments are too restrictive to adequately investigate formation properties. The emerging digital rock physics (DRP) technology in recent years effectively overcomes these constraints. Nevertheless, the current DRP faces two major challenges: the integration of multiple-resolution images and the upscaling of rock physics properties (electricity). In this paper, we propose an innovative method for assigning electrical characteristics to voxel units, enabling the integration of multi-resolution images, as well as a novel approach for establishing a new saturation model to achieve electrical property upscaling. Initially, core samples are selected and drilled based on logging data and lithology analysis, followed by multi-resolution scanning experiments, including X-ray CT, QEMSCAN, and MAPS. After that, mineral components are segmented, and multi-component digital rocks are constructed. Considering mineral voxel as the analytical units, pore characteristics within each mineral, which are extracted from MAPS, are used to generate 3-D pores by QSGS method. These generated 3-D pores are then merged with their respective mineral voxel. Subsequently, the electrical properties of the merged models are simulated and assigned to multi-component digital rock. This process enables the integration of multi-resolution images, leading to the construction of high-precision digital rocks. Additionally, high-precision digital rock-based electrical modeling is conducted, and a new saturation model is then established by combining digital rock physics, experiment rock physics, and theoretical rock physics. Finally, the new saturation model is applied to calculate saturation, accomplishing electrical property upscaling. Application results show the new saturation model improves the accuracy of saturation evaluation, demonstrating the feasibility of the upscaling method for electrical properties.

A super-hygroscopic SA-MXene@LiCl composite membrane with fast ab/desorption kinetics for efficient sorption-based atmospheric water harvesting

The daily water productivity of sorption-based atmospheric water harvesting (SAWH) materials is significantly limited by their low moisture sorption capacity and sluggish ab/desorption kinetics. Here, a thin, porous, mechanically stable and high LiCl-loading content super-hygroscopic SA-MXene@LiCl membrane (SM@LiCl) was fabricated via vacuum-assisted filtration and freeze-drying methods. The thin and porous characteristics of the cross-linked SA-MXene network significantly reduce moisture transport resistance, while the wrapped hygroscopic LiCl effectively enhances its moisture capture capacity. When applied to SAWH, this nanocomposite membrane demonstrates an impressive water uptake performance of 1.69 g g−1 within 1 h at 45 % RH and releases over 65 % of absorbed water after only 0.5 h of sunlight irradiation (1 kW/m2). With its high moisture sorption capacity and rapid ab/desorption kinetics, it can operate for up to 16 cycles per day in indoor environment, resulting in a record daily water yield of 19.46 L kg−1 at 45 % RH. The present study presents a straightforward approach for the development of high-quality sorbents with improved ab/desorption kinetics for SAWH.

Dynamic properties of mortar with oyster shell sand replacement

With the rapid expansion of construction engineering, the demand for traditional materials, particularly natural river sand, has surged, resulting in excessive resource exploitation and significant ecological damage. In response, the use of waste oyster shells as a sustainable alternative for fine aggregates has gained attention. However, limited research has been conducted on the dynamic properties of mortar with this substitution. This study explores the potential of using crushed oyster shell sand (OSS) as fine aggregates in mortar. A series of Split Hopkinson Pressure Bar (SHPB) tests under different gas pressures (pg) (0.2, 0.3, and 0.4 MPa) were carried out on mortar samples with five OSS replacement ratios (Rr) (0%, 20%, 50%, 80%, and 100%), using a water-to-cement ratio of 0.55. The results showed that when the OSS replacement rate (Rr) increased from 0 to 20%, there was a significant increase in peak stress (σmax) and elastic modulus (E), attributed to the filling effect of OSS, which enhanced the absorbed energy (Eab) and strength contribution rate (SCR). However, at Rr above 20%, a sharp decline in σmax and E was observed, primarily due to porous characteristics of OSS. Correspondingly, Eab decreased, reducing the impact resistance of mortar. Moreover, the negative SCR suggests detrimental effects on mortar integrity at higher OSS Rr levels. Predictive relationships for peak stress and elastic modulus across different replacement ratios were established in this study, providing a foundational reference for the design and assessment of the dynamic mechanical response of structures incorporating OSS.

SYNTHESIS AND CHARACTERIZATION OF ADVANCED METAL-ORGANIC FRAMEWORKS (MOFS)

Objective: This study aims to summarize, compare, and discuss the structure, synthesis techniques, and novel applications of Metal-Organic Frameworks (MOFs) as sensing materials. Specifically, it focuses on their use in sensors for detecting pharmaceuticals, pesticides, heavy metals, food additives, and other contaminants. Additionally, the study explores the antibacterial applications of MOFs due to their unique physical properties. Methods: The solvothermal process for synthesizing MOF-199 was investigated by varying the ethanol-to-water solvent ratio (1:1 to 1:2), solvothermal temperatures (85°C to 100°C), and synthesis times (24 to 48 hours). Characterization of the synthesized materials was conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis to assess the structure, surface area, and pore characteristics. Results: The results indicate that MOF-199 synthesized under the optimal conditions (100°C for 48 hours with a 1:1 ethanol-to-water ratio) exhibited a specific volume of 0.693 cm³/g, a pore volume of 11.8 Å, a BET surface area of 5518 m²/g, and crystallinity of 103%. These properties are crucial for enhancing the performance of MOFs in electrochemical sensing applications. Novelty: This paper provides a detailed overview of the antibacterial applications of MOFs and their nanocomposite forms, offering new insights into their potential for sensing a wide range of chemicals and their enhanced selectivity for electrochemical analysis. The study introduces the solvothermal synthesis of MOF-199 and presents optimized parameters for its production, contributing to the development of more sensitive, cost-effective, and versatile electrochemical sensors for detecting contaminants.

Semi-quantitative identification of pore characteristics for Yungang grotto sandstone via acoustic emission signals and information fusion convolutional neural network

Diseases of grotto can be identified via artificial intelligence (AI) techniques, but most existing AI models cannot quantify the specific Indicators, such as pore parameters. In this work, an information fusion convolutional neural network (IFCNN) integrating acoustic emission (AE) time and frequency domain signals is constructed based on quantifiable labels of pore characteristics. And the model training process is introduced and the identification performance of IFCNN was compared with that of other machine learning methods. The specific pore indicators and its corresponding refined parameter range can inverted via six weathering levels in quantifiable labels. The IFCNN model is trained by using 6048 time-frequency domain AE series data and IFCNN demonstrated superior identification performance and generalization ability compared to other 1D-CNN and machine learning models. Furthermore, 3 extra sandstone samples with different degrees of weathering are used to further investigate the pore parameter recognition performance of the IFCNN pre-trained model. It's found that the effective T2 intervals of the 3 samples were all identified incorrectly, that is, micro fissures intervals greater than 200 ms were missed. However, the accuracy of identified total bulk porosity, average pore size, and pore development coefficient is better. Except for average pore size, all other indicators are within the given interval from semi-quantified label. When the pore size distribution is about 0.5 μm–10 μm, the weathering of Yungang sandstone can be described semi-quantitatively. It is envisioned that the proposed IFCNN serves as an accurate and ready-to-use assessment tool that aids researchers or cultural heritage conservators to quickly evaluate the pore parameters of sandstone grottoes just using AE device.

Activation of bio-oil with or without pre-carbonization makes marked difference in pore development

Bio-oil, a major product from biomass pyrolysis, is a renewable source for production of functional carbon materials such as activated carbon (AC). Bio-oil can be activated directly via mixing with an activator or be pre-carbonized followed by subsequent activation. These two processes feature with distinct reaction network and might affect pore characteristics in different ways. This was investigated herein by direct activation of bio-oil or biochar from pre-carbonization of bio-oil using K2C2O4 or KOH as the activator at 800 ºC. The results indicated that bio-oil was pre-carbonized into biochar at 500 ºC improved yields of AC (83.6 % versus 17.5 % from direct activation of bio-oil with K2C2O4) through enhanced aromatic degree and resistivity to cracking. This also diminished specific surface area of resulting AC (716.3 versus 1035.5 m2g−1 from direct activation). Much more intensive cracking reactions in direct activation of bio-oil with K2C2O4 were confirmed with in-situ IR technique. This not only formed AC of more developed pore structures, especially more mesopores/macropores, but also generated gases as dominate product (yield: 74.5 %). Similar result was observed from activation with KOH, but KOH was more effective than K2C2O4 for cracking. This, however, did not result in AC of more developed pore structures, as the K2CO3 derived from KOH tended to be wrapped with organics in direct activation of bio-oil and was difficult to be washed away, blocking pores generated.

Comparison of Pore Characteristics and Constraints of Marine-Terrestrial Mud Shale

Comparison of Pore Characteristics and Constraints of Marine-Terrestrial Mud Shale

New insight into pore characteristics for cake layers formed on nanocomposite membranes: Effect of membrane surface fractality

Over the past two decades, there has been extensive research that attempts to relate membrane's performance to its surface roughness. However, applicability of this approach to nanocomposite membranes is questionable, given the highly diverse membrane structures. In this study, three types of carbon nanotube composite membranes (CNT_S, CNT_M, and CNT_L) were prepared and used to filter fluorescent polystyrene particles under favorable surface interaction conditions. The resulting cake structures were imaged using laser confocal microscopy and analyzed for pore characteristics. It was found that cake layers with lower porosity and smaller average pore size also had more tortuous and complex pore channels, leading to lower water permeability. Moreover, simulations of the cake layers with a pore network model reveal that pore radius and throat length are key factors affecting water permeability. Further application of the machine learning (ML) model accurately predicts cake permeability based on the 3D fractal dimension (2.44–2.81), anisotropy (0.64–0.81) and porosity (0.3–0.71) of the pore space and R2 of the test set reaches 0.96. Finally, the Weierstrass-Mandelbrot equation is applied to describe the self-similar fractal surfaces possessed by the CNT membranes. The respective fractal dimensions of three membrane surfaces (Df) are 2.31, 2.11 and 2.57. At a Df value of 2.31, the cake layer exhibits greater pore homogeneity and connectivity, and thus higher water permeability. Overall, this study revealed the fractal nature of CNT membrane surface and its relevance to pore structure and water permeability of the cake layers.

Fabrication of Mesoporous SiO&lt;sub&gt;2&lt;/sub&gt; Shells for Dye Adsorption Studies

The present work focuses on the fabrication of novel hybrid materials for toxic dye removal from an aqueous environment. Nanocarbon template (20-30 nm) was coated with tri-ethyl-orthosilicate (TEOS). The core-shell structure developed was further air pyrolyzed at 600 °C to produce mesoporous silica shells. The pore structures and characteristics of the material were evaluated using XRD, nitrogen adsorption studies, SEM, and TEM. Owing to the hierarchical porosity in range of 1-4 nm and 10-20 nm their adsorption studies were investigated for Phenol-Red. Dye adsorption studies performed revealed 98% removal efficiency with only 20 mg of adsorbent dose within 15 minutes.

Synthesis and application of Ho³⁺ doped BaGd₂ZnO₅ nanophosphors for enhanced latent fingerprint development and poroscopy

In this study, Ho³⁺-doped BaGd₂ZnO₅ (1–11 mol%) nanophosphors (BGZO:Ho3+ NPs) were synthesized through combustion synthesis, utilizing Spirulina leaf extract as a natural green fuel. Luminescence studies revealed that the BGZO:Ho³⁺ phosphors exhibit a strong green emission primarily resulting from the 5S2→5I8 transition of Ho³⁺ ions. The optimal doping concentration was found to be 7 mol % Ho³⁺, which yielded the highest luminescence efficiency. Furthermore, the CIE chromaticity coordinates for BGZO:7Ho³⁺ were accurately determined to be (0.2595, 0.7290), with a color purity (CP) of 99.98 %. These results indicate the potential of this material for producing high-quality green emissions suitable for solid-state lighting and display applications. Optimized BGZO:Ho3+ NPs were utilized for latent fingerprints (LFPs) development via the powder dusting method. Under 365 nm UV light, the NPs effectively revealed Level I-III fingerprints (FPs) details, including ridge patterns, minutiae, and sweat pore features, on various substrates such as glass, plastic, and metal. The high luminescence of BGZO:Ho3+ NPs under UV illumination offers a sensitive and non-destructive method for enhancing FPs visibility, making it a promising tool for forensic applications. In addition, this study focuses on FPs poroscopy, examining the detailed pore structure of LFPs for forensic identification. Using advanced imaging techniques, we analyzed sweat pore distribution, size, and shape across various substrates and conditions. A detailed poroscopic analysis of LFPs, focusing on key parameters such as pore interspacing (165–332 μm), pore size (4140–9956 μm2), shapes (elliptical, rhomboid, triangular, square and rectangular) and pore angle (167°–179°). Further, a mathematical model was developed using Python-based software to enable precise and accurate analysis of FPs, enhancing clarity and identification accuracy, supporting the uniqueness of FPs beyond ridge patterns. The results demonstrate the potential of poroscopy for enhancing FPs analysis by offering an additional layer of precise biometric data.

Enhanced ballasted magnetic coagulation process based on one-step pyrolysis synthesis of sludge-derived AC@MNPs for advanced purification of secondary effluent from wastewater treatment plants: specific removal of low molecular weight organic matter

The removal of dissolved organic matter from secondary effluent in sewage treatment is a significant challenge, necessitating the development of green and efficient composite magnetic materials for coagulation. In this study, activated carbon-modified magnetite nanoparticles (AC@MNPs) were synthesized via one-step activation pyrolysis using iron sludge as a precursor. The ballast coagulation process employed AC@MNPs as both magnetic species and adsorbent, with polymeric aluminum chloride (PACl) as a coagulant, for advanced treatment of secondary effluent. A response surface methodology identified optimal pyrolysis conditions: an activation ratio (KOH/ST) of 1.2, a pyrolysis time of 1 h, and a temperature of 640 °C. The influence of pyrolysis temperature (600 ∼ 700 °C) on the morphology and pore characteristics of AC@MNPs was investigated, highlighting its significance in coagulation performance. Characterization through XRD, VSM, and FTIR confirmed the favorable settling properties of the composite magnetic flocs and recyclability of AC@MNPs. Coagulation experiments revealed a synergistic effect of AC@MNPs and PACl, enhancing the removal of UV254 and COD from 33.4 % and 36.2 % (with PACl alone) to 74.02 % and 76.53 %, respectively. The overall performance of the ballast coagulation process was evaluated, demonstrating effective removal of organics of various molecular weights. Finally, the coagulation mechanism was systematically discussed. Overall, this research offers insights into the application of magnetic coagulation technology for wastewater treatment advancements.

Development of nanoporous carbon models with tunable pore structures via the random packing-virtual atom method

Nanoporous carbon (NPC) is widely utilized due to its highly developed pore structure. The complex structure-property relationships of NPC necessitate simulation methods to complement experimental approaches, with structural model construction serving as the foundation. Regulating pore structures during construction of NPC models poses a significant challenge, and existing strategies for introducing pores have inherent limitations. In this work, NPC models were constructed using the random packing method, incorporating virtual atoms (VAs) to regulate pore development, achieving targeted control over the pore structure. The results indicate that the system density is a critical factor in determining the porosity range of NPC models, whereas VAs provide an effective means to regulate pore characteristics. By adjusting the number and radius of VAs, the pore characteristics of the models can be tuned, although their effects on different features vary. The number of VAs significantly influences SSA, which increases with the number of VAs, whereas VA radius predominantly affects porosity, increasing as the radius expands. Furthermore, the NPC-SDG-AC model was developed with an SSA of 968 m2/g and a pore size distribution consistent with actual microporous distribution. NPC-1, NPC-2, and NPC-3 models were also constructed, exhibiting mesoporous, large microporous, and small microporous characteristics.

Study on the Microscopic Pore Characteristics and Mechanisms of Disturbance Damage in Zhanjiang Formation Structural Clay

To investigate the microscopic pore evolution characteristics of Zhanjiang Formation structural clay during the disturbance process, unconfined compressive strength tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were conducted on disturbed samples subjected to various disturbance conditions after vibrational disturbance. Based on the evolution characteristics of the microstructure, the microscopic pore characteristics of the disturbance damage of Zhanjiang Formation structural clay were examined. The results indicate the following. (1) The porosity in three-dimensional visualization images of the microstructure reconstructed by ArcGIS 10.1 increases with the disturbance degree, showing a linear growth trend. (2) The correlation analysis between macroscopic mechanics and microscopic pores shows that the unconfined compressive strength of Zhanjiang Formation structural clay is mainly affected by its porosity, with a significant linear negative correlation. Based on this, a reasonable regression model between the microscopic porosity and the unconfined compressive strength has been established. The model can rapidly estimate the unconfined compressive strength from porosity data, facilitating the assessment engineering properties of the soil. (3) The microscopic pore structure of Zhanjiang Formation structural clay exhibits prominent Menger fractal characteristics. The three-dimensional pore fractal dimension has a certain positive correlation with the disturbance degree, and can be utilized to characterize the pore structure and complexity, serving as a significant parameter for the quantitative evaluation of the pore structure characteristics of Zhanjiang Formation structural clay. Consequently, the complexity of the pore structure of the engineering soil can be evaluated by the pore fractal dimension. (4) The impact of disturbance on soil is primarily manifested in the structural changes in secondary clay minerals, transitioning from a relatively intact to a fully adjusted state. During this process, interparticle pores continuously increase, pore structure complexity increases, and interparticle cementation weakens, resulting in the continuous degradation of unconfined compressive strength. This study contributes to a deeper understanding of the disturbance damage characteristics of Zhanjiang Formation structured clays from a microscopic pore perspective, providing a theoretical basis for the engineering construction and operational maintenance in regions with Zhanjiang Formation structural clay.

Formation of C2 and C3 hydrocarbons through photocatalytic CO2 conversion on vertical Bi2WO6 nanosheets

In contrast to conventional nanostructured photocatalysts that only catalyze the conversion of CO2 into C1 compounds of CO and CH3OH, in this study, the Bi2WO6 nanosheets are deliberately grown to form a unique vertical configuration for achieving superior photocatalytic CO2 conversion in the production of additional C2/C3 hydrocarbons, such as HCOOCH3, CH3CHO, and CH3COCH3. These products can serve as high-caloric-value fuels and chemical feedstocks, contributing to sustainability by potentially replacing fossil fuels. The vertical Bi2WO6 nanosheets predominantly expose (010) crystal planes to the CO2 atmosphere. By modifying the nanosheet to display a jagged porous feature that exposes a higher proportion of edge surfaces perpendicular to the main exposure faces, the resulting vertical porous Bi2WO6 nanosheets catalyze the formation of additional hydrocarbons, including CH4 and CH3CH2CHO. This enhancement further strengthens the sustainability merit of this photocatalytic process. To support these experimental findings, density functional theory calculations verify the enhanced photocatalytic activity of a characteristic edge face, the Bi2WO6 (100) plane, compared to the Bi2WO6 (010) plane in the conversion of CO2 and H2O into hydrocarbons requiring multielectron transfer. This study highlights the effectiveness of the vertical Bi2WO6 nanosheets, primarily featuring exposed (010) crystal planes along with additional exposed edge faces, in promoting sustainable CO2 conversion reactions for the production of C2/C3 hydrocarbons involving multielectron transfer processes.

Constructing Flexible Crystalline Porous Organic Salts via a Zwitterionic Strategy.

The unique ionic channels and highly polar pore structures have distinguished crystalline porous organic salts (CPOSs) from conventional porous frameworks in the past decade. Up to now, CPOSs were all constructed by a monoionic strategy, in which two types of building units individually bearing anionic or cationic groups were introduced, thus increasing complexity in the synthesis of CPOSs. In this study, by utilizing stereoisomeric compounds of TPE-NS-Z or TPE-NS-E bearing both anionic and cationic groups as a single building unit, the zwitterionic strategy was proven feasible in constructing CPOSs. Benefiting from the single building unit, the zwitterionic strategy simplified the preparation process and reduced the difficulty in studying the aggregation behavior of building units into CPOSs. And also, this novel strategy enabled precise control of the finally obtained CPOSs through fine-tuning of the initial building units. Surprisingly, the special parallel/vertical alternated stacking mode and unique ionic interaction networks in the crystal structure provided the flexible pore characteristic of CPOS-E, which further guaranteed the multitime controllable release of highly polar chemicals in different solvents.

Structural and Textural Characteristics of Municipal Solid Waste Incineration Bottom Ash Subjected to Periodic Seasoning

The objective of this study was to determine the structural and textural description of municipal solid waste incineration (MSWI) bottom ash that was subjected to a six-month seasoning process. Bottom ash samples, with a particle size fraction of 0.063–0.1 mm, were seasoned in a closed landfill and collected for laboratory analyses at monthly intervals. The research focused on determining the structural parameters, using methods such as nuclear magnetic resonance spectroscopy (1H NMR), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), and the textural parameters, using low-pressure nitrogen adsorption (LPNA) at −196.15 °C. The analyses of the porous structure of the bottom ash samples revealed differences in texture of ASH 1 to ASH 6, specifically in the pore volume (micro- and mesopores), specific surface area, and pore size distribution. Changes in the structural and porous characteristics of the samples were attributed to the duration of the seasoning process. The results of the structural analysis of the bottom ash suggest its application in the concrete industry, potentially enhancing the long-term mechanical strength of concrete. The results of the textural analysis indicate the possible use of MSWI bottom ash in environmental applications, as the internal surface area could be further developed.

Critical heat flux enhancement by porous coatings and prediction model development under External Reactor Vessel Cooling conditions

Critical heat flux (CHF) is the important limitation to estimate the effectiveness of the In-vessel retention (IVR) strategy for the severe accident mitigation. However, as the reactor power increases in the new-generation nuclear power plant, it is necessary to ensure the sufficient safety margin by taking some measures for the CHF enhancement. Porous coatings are recognized as an effective technique to improve the CHF. In this paper, the applicability of the porous coatings has been evaluated. The porous coatings consist of a dense layer and a porous layer. CHF experiments were constructed at the REPEC-III facility with 1:1 height ratio to the prototypic External Reactor Vessel Cooling (ERVC) environment. CHF on the porous surface is enhanced 32.4%–48.5 % under the ERVC conditions. Based on the experimental data, a mechanistic model considering the porous surface characteristics to predict CHF of the flow boiling under the ERVC natural circulation is developed and has a good predictive ability. The predicted CHF is compared with the experimental data of large-scale ERVC experiments. The mechanistic model can predict CHF within ±15 % error. Through the full-height experimental and theoretical analyses, porous coatings are an effective method to improve CHF and has a good application perspective for the IVR strategy in the nuclear power plant.