Volume Swelling Research Articles

Experimental Study on the Properties of Basalt Fiber–Cement-Stabilized Expansive Soil

Expansive soil is prone to rapid strength degradation caused by repeated volume swelling and shrinkage under alternating dry–wet conditions. Basalt fiber (BF) and cement are utilized to stabilize expansive soil, aiming to curb its swelling and shrinkage, enhance its strength, and ensure its durability in dry–wet cycles. This study examines the impact of varying content (0–1%) of BF on the physical and mechanical characteristics of expansive soil stabilized with a 6% cement content. We investigated these effects through a series of experiments including compaction, swelling and shrinkage, unconfined compressive strength (UCS), undrained and consolidation shear, dry–wet cycles, and scanning electron microscope (SEM) analyses. The experiments yielded the following conclusions: Combining cement and BF to stabilize expansive soil leverages cement’s chemical curing ability and BF’s reinforcing effect. Incorporating 0.4% BFs significantly improves the swelling and shrinkage characteristics of cement-stabilized expansive soils, reducing expansion by 36.17% and contraction by 28.4%. Furthermore, it enhances both the initial strength and durability of these soils under dry–wet cycles. Without dry–wet cycles, the addition of 0.4% BFs increased UCS by 24.8% and shear strength by 24.6% to 40%. After 16 dry–wet cycles, the UCS improved by 38.87% compared to cement-stabilized expansive soil alone. Both the content of BF and the number of dry–wet cycles significantly influenced the UCS of cement-stabilized expansive soils. Multivariate nonlinear equations were used to model the UCS, offering a predictive framework for assessing the strength of these soils under varying BF contents and dry–wet cycles. The cement hydrate adheres to the fiber surface, increasing adhesion and friction between the fibers and soil particles. Additionally, the fibers form a network structure within the soil. These factors collectively enhance the strength, deformation resistance, and durability of cement-stabilized expansive soils. These findings offer valuable insights into combining traditional cementitious materials with basalt fiber to manage expansive soil hazards, reduce resource consumption, and mitigate environmental impacts, thereby contributing to sustainable development.

Preparation of MoS2 nanosheets/nitrogen-doped carbon nanotubes/MoS2 nanoparticles and their electrochemical energy storage properties

Inferior electrical conductivity, huge volume swell, shuttle effect and slow redox reactions in Li-S batteries restrict their practical applications. In this study, molybdenum disulfide nanosheets anchored on nitrogen-doped carbon nanotubes encapsulating molybdenum disulfide nanoparticles (MoS2/NC/MoS2 NTs) were prepared by heat treatment, ammonia etching, high-temperature sulfurization, and solvent-thermal in-situ growth using polypyrrole-coated molybdenum trioxide nanorods (MoO3 NRs) as templates. The hollow structure of nitrogen-doped carbon nanotubes and the high specific surface area are conducive to increasing sulfur loading, increasing the contact area of electrolyte, accelerating the electron transport, and shortening the lithium ion transport route. The MoS2 nanosheets on the outer layer of the nitrogen-doped carbon tubes and the MoS2 particles wrapped inside can anchor polysulfides by chemisorption, slowing down the shuttle effect and enhancing the energy storage performance of lithium-sulfur batteries. The MoS2/NC/MoS2/S nanotubes (MoS2/NC/MoS2/S NTs) maintain a capacity of 498.9 mAh g−1 over 500 cycles at 1.0 A g−1, with an average single-cycle capacity decay rate of 0.061 %. The density functional theory calculations, the adsorption experiments, and the X-ray photoelectron spectroscopy results all confirm that the MoS2/NC/MoS2 NTs are able to anchor lithium polysulfides through strong adsorption, thus effectively mitigating the shuttle effect of polysulfides. The synthesis of MoS2/NC/MoS2/S NTs in this study is of important significance for the development of advanced lithium-sulfur batteries.

Acetylation of Aspen and Alder Wood - Preliminary Tests

An experimental study of the physical and mechanical properties of untreated and acetylated wood was conducted. The effect of acetylation on wood density was investigated. It was established that the density of the samples generally decreases after acetylation. As the level of acetylation increases, the fiber saturation point decreases in both conifers and hardwoods. Acetylation of wood helps to reduce the sorption properties of wood. The amount of swelling was analyzed. For untreated wood (aspen and alder), the volume swelling index is at the level of 7.5 %. Acetylation contributes to the stability of the geometric dimensions of structures, as the volume swelling index for aspen decreased by 4 times, for alder – by 2 times. An increase in the amount of swelling along the fibers is observed in all samples. Regarding the nature of the destruction of the samples during compression, the aspen (both untreated and acetylated) only crumples without visible signs of destruction. In some samples of alder, partial exfoliation is visible. It was found that acetylation has an ambiguous effect on the mechanical properties of wood of both species.

Production of noodles using cocoyam (Colocasia esculenta)

The potential of making noodles using cocoyam flour was investigated. Cocoyam (Taro) and wheat flour were prepared. The proximate compositions of 100% cocoyam (C) flour, 100% wheat (W) flour, 50:50, and 70:30 blends of cocoyam-wheat (CW) flour were determined. Noodles were produced from cocoyam and wheat flour and their blends. The mean proximate composition of 100% cocoyam flour was found to be 11.19% amylose content, 8.70% crude protein, 4.86% ash, 0.60% fat content, 5.06% moisture content (wb), 6.38% crude fiber, and 72.22% carbohydrates with a swelling volume of 17.45 mL/g. The mean textural quality characteristics of the 100% cocoyam flour noodles were 5.88% cooking loss, 9.18 N/m2 tensile strength, 39.75 Pa elasticity, and 74.06 mm firmness with a cooking time of 4.31 mins. The 100% cocoyam noodles were rated 5.0, 3.0, 4.0, 5.0, and 4.0 for appearance, flavor, hardness, texture, and overall acceptability, respectively on a 9- point hedonic scale. In comparison with 100% wheat flour noodles with an acceptability of 7.0, the 100% cocoyam noodles had a lower score. The 50:50 cocoyam-wheat flour blend noodles, however, scored 6.0 on acceptability which was very close to that of 100% wheat noodles. This study showed that though noodles could be made from 100% cocoyam flour, a 50:50 cocoyam-wheat flour blend would make better quality noodles in terms of nutrition and overall acceptability.

A novel dual-network CO2-responsive particle gel for mitigating CO2 channeling and leakage in hydrocarbon recovery and carbon storage

In this work, we developed and systematically evaluated a novel dual-network CO2-responsive preformed particle gel (DN-CRPPG) to address CO2 channeling and leakage in hydrocarbon recovery and carbon sequestration. The work was proven an effective effort to overcome the insufficiency of traditional channeling-control chemicals due to severe dehydration and degradation in contact with CO2. We focused on placement and plugging behavior of the DN-CRPPG in fractured reservoirs under various circumstances. Results of high-pressure vessel test show that DN-CRPPG expanded further when exposed to supercritical CO2. The responsive swelling ability was enhanced with the increase of pressure. Core flooding and plugging experiments show significantly improved CO2-channeling control ability compared with traditional non-responsive particle gels. Three key mechanisms were observed to be responsible for the improved performance. First, the CO2-responsive behavior resulted in volume swelling of DN-CRPPG. Therefore, the void spaces among the particles were occupied by the swelled gel particles, making the DN-CRPPG exhibit an in-situ self-reinforcement behavior in plugging ability. Second, the dual network structure with a relatively rigid network and a more flexible one enhances its mechanical ability and resistance to CO2 flush. Third, the CO2-repsonsiveness enabled the new gel a remarkably higher resistance to CO2 than that to water, while traditional gel is the opposite. This behavior is favorable for balancing the mobility of CO2 and water as the fact that CO2 itself is much more mobile due to low viscosities. Significant CO2 breakthrough mitigation and oil recovery improvement were demonstrated after treatment with the new gel (>30 %). This work is supposed to provide guidance for improving the success of hydrocarbon recovery and carbon storage by more effectively mitigating CO2 channeling and leakage.

Consecutive covalent bonds reconstruct robust dual-interfaces by carbonized binder to enable conductive-additive-free durable silicon anode

The substantial volume expansion and poor electrical conductivity tremendously hinder the utilization of high silicon (Si) content anode with compelling capacity. Herein, we propose an efficient strategy to stabilize Si-based anodes by carbonization of the slurry-casting Si electrode with a conductive polyoxadiazole (POD) binder. Such POD-derived materials can form a nitrogen/sulfur-rich carbon network, not only serving as a resilient scaffold to buffer the volume swelling and firmly adhere the Si to the current collector by robust dual-interfaces bonding but also evolving into a conductive matrix to facilitate the electron/ion transport. The conductive-additive-free Si electrode possesses a high Si content of up to 84 %. It exhibits a high initial Coulombic efficiency (86.34 %), competitive gravimetric capacity (3340 mAh g−1), stable cycling performance (the capacity retention rate reaches 79 % after 1000 cycles), commercial-level areal capacity (5.32 mAh cm−2), and outstanding rate capability (1673 mAh g−1 at 5.0 A g−1). This work offers a scalable modification idea and forward-looking perspective for high-performance Si-based anodes in next-generation lithium-ion batteries.

DUMB CANE (DIEFFENBACHIA SEGUINE (JACQ.) SCHOTT) EXTRACT NANOEMULSION: PREPARATION, CHARACTERIZATION AND ITS ACTIVITY AS AN INFLAMMATION-INDUCING AGENT IN RATS

Objective: This study aimed to characterize Dumb cane extract nanoemulsion for injection preparation and test its activity as an inflammation-inducing agent in rat intraplantar with IL-6 and TNF-alpha parameters in blood serum as well as the swelling response in paw. Methods: Nanoemulsion was made from an emulsion base of olive oil, coconut oil, tween 80 propylene glycol, and water for injection, as well as varying concentrations of Dumb cane extract (1%, 2%, and 4%) using vortex mixing and sonication methods. The characterization included particle size, zeta potential, and polydispersity index using the Zetasizer tool. Induction was carried out intraplantar in male rats. The parameters observed were the volume of swelling in paw and IL-6 and TNF-alpha in blood serum. Results: Dumb cane extract nanoemulsion concentrations of 1%, 2%, and 4% have particle size characteristics in the range of 20.3±0.17–30.1±0.68 nm, and zeta potential -31.4±1.59–33.1±1.33 mV. Dumb cane nanoemulsion can induce intraplantar inflammation with high IL-6 and TNF-alpha levels, significantly different from normal controls. Volume swelling occurred 4 h after intraplantar induction at a nanoemulsion concentration of 4%. Conclusion: Dumb cane extract nanoemulsion can be an alternative agent for inducing intraplantar inflammation in rat models.

Gadung (Dioscorea hispida) tuber starch modified by freeze moisture treatment and heat moisture treatment: a study of functional, pasting, and physicochemical properties

ABSTRACT Gadung starch has limitations in several functional properties and thermal stability. Modifying starch through temperature treatments such as Freeze Moisture Treatment (FMT) and Heat Moisture Treatment (HMT) potentially improves these weaknesses. This research aimed to determine the effects of FMT and HMT on the functional, pasting, and physicochemical properties of gadung starch. This study consisted of a variety of treatments, namely native starch, FMT, HMT 100°C, HMT 110°C, FMT + HMT 100°C, and FMT + HMT 110°C. The results showed that FMT and HMT treatments significantly affected the functional, pasting, and physicochemical properties of gadung starch. The combination modification treatment of FMT + HMT 110°C increased swelling volume by 1.44 times, and water absorption capacity increased by 1.37 times. This was confirmed by the formation of porous and amorphous starch granules. Modified starch also had the best heat stability, as indicated by a low breakdown viscosity of 31.00 ± 9.90 cP. FMT+HMT110°C modified treatment was the best treatment because it had more pores, cracks, and higher swelling volume. The starch crystallinity index of modified starch decreased from 35.75 to 31.58 and changed the crystallinity type from B-type to A-type. The starch modification did not cause changes in functional groups but reduced crystallinity as indicated by the smaller ratio of the bands at 1045/1022 and the higher ratio at 1022/995 from FTIR spectra. Thus, FMT and HMT could effectively improve the characteristics of gadung starch by forming heat-stable amorphous starch.

Molecular Insights into Soaking in Hybrid N2-CO2 Huff-n-Puff: A Case Study of a Single Quartz Nanopore-Hydrocarbon System.

Hybrid N2-CO2 huff-n-puff (HnP) has been experimentally demonstrated to be a promising approach for improving oil recovery from tight/ultratight shale oil reservoirs. Despite this, the detailed soaking process and interaction mechanisms remain unclear. Adopting molecular dynamic simulations, the soaking behavior of hybrid N2-CO2 HnP was investigated at the molecular and atomic levels. Initially, the soaking process of fluid pressure equilibrium after injection pressure decays in a single matrix nanopore connected to a shale oil reservoir is studied. The study revealed that counter-current and cocurrent displacement processes exist during the CO2 and hybrid N2-CO2 soaking, but cocurrent displacement occurs much later than counter-current displacement. Although the total displacement efficiency of the hybrid N2-CO2 soaking system is lower than that of the CO2 soaking system, the cocurrent displacement initiates earlier in the hybrid N2-CO2 soaking system than in the CO2 soaking system. Moreover, the N2 soaking process is characterized by only counter-current displacement. Next, the soaking process of fluid pressure nonequilibrium before the injection pressure decays is investigated. It was discovered that counter-current and cocurrent displacement processes initiate simultaneously during the CO2, N2, and hybrid N2-CO2 soaking process, but cocurrent displacement exerts a dominant influence. During the CO2 soaking process, many hydrocarbon molecules in the nanopore are dissolved in CO2 while simultaneously exhibiting a substantial retention effect in the nanopore. After pure N2 injection, there is a tendency to form a favorable path of N2 through the oil phase. The injection of hybrid CO2-N2 facilitates the most significant cocurrent displacement effect and the reduction in residual oil retained in the nanopore during the soaking process, thus resulting in the best oil recovery. However, the increase rate in total displacement efficiencies of the different soaking systems over time (especially the hybrid N2-CO2 soaking system) was significantly larger before than after injection pressure decays. Additionally, the displacement effect induced by oil volume swelling is significantly restricted before the injection pressure decays compared to the soaking process after the injection pressure decays. This study explains the role of CO2-induced oil swelling and N2-induced elastic energy played by hybrid N2 and CO2 at different stages of the hybrid N2-CO2 soaking process before and after pressure decays and provides theoretical insights for hybrid gas HnP-enhanced recovery. These pore-scale results highlight the importance of injection pressure and medium composition during the soaking process in unconventional oil reservoirs.

Structure-activity relationships of natural and synthetic lathyrane-based diterpenoids for suppression of NLRP3-driven inflammation and gouty arthritis

Lathyrane-based diterpenoid is one of the critical bioactive elements of Euphorbia lathyris L., a widely used traditional Chinese medicine for the treatment of inflammation and infection. In this study, we introduced and evaluated seven synthetic or natural lathyrane-based diterpenoids with the same core structure but notable structural variations at specific positions, for their anti-inflammatory and gout-alleviating properties. There was no significant cytotoxicity below 10 μM among the initial test of the cell counting kit 8 of the seven candidate derivatives (compounds 13 to 19) in this work. Furthermore, maintaining the acyloxy group at 15-C position and the strongly hydrophobic aryl structure at 3-C and 5-C positions, compounds 15 (Euphorbia factor L3, EFL3) and 17 strikingly inhibited the production of IL-1β related to the actuation of the inflammasome in our study. The ELISA assay indicated that the anti-inflammatory effects of EFL3 were better associated with MSU stimulation than other second-line pathways triggered by inflammasome. Further examinations on the acute paw gout model in C57BL/6 mice showed that EFL3 had a significantly inflammatory retarding effect by intraperitoneal injection. It decreased swelling volume as well as the cleavage and activation of local IL-1β and casepas-1 in the paw. To conclude, our findings reveal several potential key structure–activity relationships that govern the anti-inflammatory effects of lathyrane-type diterpenoids, the dispensable acyl group at the 15-C position, the importance of maintaining the spatial structure of the B-ring, and the potential importance of hydrophobic substituents at the 3-C position. These insights may provide guidance for the structural design of lathyrane-type agents in the future; furthermore, we found that the lathyrane-based diterpenoid EFL3 is a potential agent for gout that is expected to provide a novel therapeutic strategy for inflammation intervention.

Refinability of mercerized softwood kraft pulp

In this study, the impact of mercerization and PFI refining on the properties of softwood kraft pulp was investigated. Never-dried softwood kraft pulp was treated with 15 wt% NaOH to generate highly hydrated fibers, followed by PFI refining to increase pulp fibrillation and porosity. The original and modified pulp properties were assessed for morphological and chemical composition. Differential scanning calorimetry (DSC) tests and water retention value (WRV) measurements were conducted to evaluate pulp swelling behavior and porosity. Fiber bonding potential and strength properties were evaluated from handsheets of mercerized and unmercerized pulp. Mercerization with 15 wt% NaOH successfully converted cellulose I to cellulose II, leading to slightly increased pulp swelling and micropore volume. However, the mercerization reduced handsheet strength properties. Furthermore, PFI refining resulted in a negligible enhancement of bonding in mercerized pulp, in stark contrast to its significant effect on unmercerized kraft pulp.

Hydrogen isotope population near dislocations in zirconium from molecular dynamics

Performance of zirconium tritides used for hydrogen isotope storage is significantly changed under reactor environments. This can be attributed to the formation of various radiation-induced dislocations. To help gain insight, molecular dynamics simulations have been employed to investigate hydrogen isotope population in zirconium containing different types of edge dislocations. Our studies reveal that hydrogen isotope concentration is highest near the tensile side of dislocation cores and varies based on dislocation type. This increase in hydrogen isotope concentration can be explained by the Boltzmann equation based on calculations using swelling volume and pressure field, with significantly reduced computational cost. Strikingly, because hydrogen isotope in the compressive regions of dislocations is depleted, the overall hydrogen isotope content is found to be unchanged by dislocation formation. These results counter the previous view that the dislocation trapping effect increases hydrogen isotope solubility and provide an understanding of changes in hydrogen isotope pressure under reactor conditions. By elucidating the impact of dislocations on hydrogen isotope storage performance, this research offers insights for optimizing zirconium tritides in nuclear applications. and contributes to the advancement of hydrogen isotope storage materials.

Volume changes and consolidation of expansive subgrades under short- and long-term effects of freeze–thaw cycles

ABSTRACT Pavements and light structures constructed on expansive subgrade layers have experienced severe damage due to volume changes. These layers have been exposed to climatic changes such as freeze–thaw (FT) cycles. Accurate estimation of design parameters regarding heave/settlement is essential for sustainable performance. This work study the instantaneous and long-term effects of successive FT-cycles on the volume stability, swelling, and compressibility characteristics of natural and lime-treated expansive subgrades. Volume changes were traced during successive 15FT cycles. Swelling and consolidation characteristics were studied immediately after FT-cycles. The long-term effect of FT was tested at different recovery periods around year. FT-cycles significantly affects volume changes and compressibility, this effect is proportional to soil type and limited up to a certain number of FT-cycles. During the long-term recovery, a considerable part of underwent deformation is a permanent and not recovered, even after year the soil still memorizes this effect. Due to the propagated cracks, the plastic deformation increased with increase in FT-cycles.

Polymers of intrinsic microporosity with alkaline pyrrolidine and piperidine functional groups for high-temperature proton exchange membranes

Recently, the polymers of intrinsic microporosity (PIMs) exhibit good potential in high-temperature proton exchange membrane fuel cells (HT-PEMFCs) due to their tunable microporosity and functionality. In this paper, alkaline pyrrolidine and piperidine functional groups were introduced onto PIM-1 via the classical Mannich reaction obtaining PIM-1/PIM-Py-50 and PIM-1/PIM-MePi-50. It was found that, compared with commercial Meta-polybenzimidazole (m-PBI) membrane, PIMs membranes showed superior retention of phosphoric acid (PA) and conductivity due to their grafting alkaline groups and rich micropores. After equilibration under 80 °C/40 % relative humidity (RH) for 150 h, the PA retention of PA doped PIM-1/PIM-Py-50 (PIM-1/PIM-Py-50/PA) and PA doped PIM-1/PIM-MePi-50 (PIM-1/PIM-MePi-50/PA) membranes were 74.13 % and 68.52 %, respectively, much higher than PA doped m-PBI (m-PBI/PA) (45.73 %). PIMs membranes maintain excellent dimensional and conductivity stability at 160 °C operating conditions, e.g. PIM-1/PIM-Py-50/PA membrane showed area swelling retention and volume swelling retention of 84.69 % and 82.19 % after 230 h at 160 °C. In addition, with the similar PA uptake, PIMs membranes displayed higher conductivity and peak power density (PPD) at 160 °C. In the accelerated stress test (AST) the PPD of the fuel cell (FC) with the PIM-1/PIM-Py-50/PA membrane remained 81.25 % after 200 aggressive start-up/shut-down cycles at 80 °C. Therefore, PIM-based membranes alkaline groups exhibit a wider temperature operating window, providing theoretical guidance for the design and study of the next generation of high-temperature proton exchange membranes (HT-PEMs).

Menaquinone-4 Alleviates Neurological Deficits Associated with Intracerebral Hemorrhage by Preserving Corticospinal Tract in Mice.

Menaquinone-4 (MK-4) is an isoform of vitamin K2 that has been shown to exert various biological actions besides its functions in blood coagulation and bone metabolism. Here we examined the effect of MK-4 on a mouse model of intracerebral hemorrhage (ICH). Daily oral administration of 200mg/kg MK-4 starting from 3h after induction of ICH by intrastriatal collagenase injection significantly ameliorated neurological deficits. Unexpectedly, MK-4 produced no significant effects on various histopathological parameters, including the decrease of remaining neurons and the increase of infiltrating neutrophils within the hematoma, the increased accumulation of activated microglia/macrophages and astrocytes around the hematoma, as well as the injury volume and brain swelling by hematoma formation. In addition, ICH-induced increases in nitrosative/oxidative stress reflected by changes in the immunoreactivities against nitrotyrosine and heme oxygenase-1 as well as the contents of malondialdehyde and glutathione were not significantly affected by MK-4. In contrast, MK-4 alleviated axon tract injury in the internal capsule as revealed by neurofilament-H immunofluorescence. Enhanced preservation of the corticospinal tract by MK-4 was also confirmed by retrograde labeling of neurons in the primary motor cortex innervating the spinal cord. These results suggest that MK-4 produces therapeutic effect on ICH by protecting structural integrity of the corticospinal tract.

Grain boundary effects on chemical disorders and amorphization-induced swelling in 3C-SiC under high-temperature irradiation: From atomic simulation insight

High-temperature irradiation-induced amorphization in SiC is a crucial factor leading to swelling. This study employs atomistic simulations to clarify the effects of experimental irradiation damage (1.0 dpa) in polycrystalline 3C-SiC at 1000 K. The findings reveal amorphization and swelling thresholds at 0.45 dpa and 7.45 %, respectively. Interestingly, dose threshold for amorphization does not align with chemical bonding, volume swelling, or enthalpy thresholds. Instead, a competitive mechanism emerges between grain boundaries and the grain core in the evolution of chemical disorder and clusters. Moreover, as amorphization saturates and grain boundaries annihilate, the degradation of tensile strength and Young's modulus stabilizes at 21.1 GPa and 124.2 GPa, respectively. Notably, grain boundaries exert a significant influence on defect cluster formation during amorphous evolution and dominate the initial deterioration of mechanical properties at low damage doses. This study enhances our understanding of how grain boundaries and chemical disorder mechanisms impact amorphization SiC.

The strategy of micropore confinement via organic macrocyclic cavities for designing novel high-performance proton exchange membranes

The high-temperature hydrogen proton exchange membrane fuel cell is considered a disruptive technology for future energy applications. However, the weak binding strength between the proton carriers (phosphoric acid molecules) with polymer chains reduces the operational stability and proton transfer efficiency at conditions of high temperature and low humidity. In this work, a strategy of micropore confinement via organic macrocyclic cavities (sulfonic calix[4]arenes, sulfonic calix[8]arenes, sulfonated β-cyclodextrin) was developed for designing novel mixed matrix membranes functioning as high-temperature hydrogen proton exchange membranes. Benefitting from the confined micropores constructed by supramolecular cavities, the obtained mixed matrix membranes showed a higher uptake and retention capability of phosphoric acid as well as lower membrane swelling, yielding an enhanced proton conductivity. The proton conductivity of the mixed matrix membranes was 2–3 times higher while the conductivity attenuation was only 58.6% comparing with neat PBI membrane, (140℃, relative humidity = 0). In addition, due to the good compatibility caused by hydrogen bonding between fillers and polymer chains, the volume swelling was only 14% and the mechanical strength of the obtained mixed matrix membranes increased. We believe the strategy of micropore confinement via organic macrocyclic cavities for designing the novel mixed matrix membranes is thought to be of great significance for the research on high-temperature proton exchange membrane.

Properties and microstructure evolution of Pisha sandstone after water/alkali leaching

Alkali-activated aluminosilicate minerals for the production of geopolymer building materials provide low-carbon and low-energy advantages compared to OPC. Pisha sandstone (PS) is a mudstone/sandstone rich in silica and aluminium, but it cannot be used directly as an engineering material due to the expansion of soggy clay minerals. In this study, the PS was modified via water and alkali leaching pretreatments, and the modified PS was used to investigate the feasibility of eliminating or attenuating the swelling of montmorillonite, and the alkali activation behavior of the PS system, respectively. The stirring frequency, dosage and types of leaching agent, and leaching time were considered as the variables. The ion concentration of the leachate was characterized using an inductively coupled plasma mass spectrometer (ICP-MS). The modified and untreated PS were characterized using a range of analytical techniques, including particle size analysis, powder XRD, SEM/EDX, TGA, and its free swelling volume in water, as well as the mechanical properties of the specimens prepared as cylinders. The results show that water leaching reduces the particle size of PS, diminishes the span of its particle size distribution, and decreases the relative amount of montmorillonite in PS. Montmorillonite undergoes dissolution/ion exchange under alkali leaching. With increasing alkali concentration and leaching time, the phase changes from Ca-montmorillonite to Na-montmorillonite to glassy phase silica-aluminate. The amorphous N-A-S-H and C-A-S-H coexist in the system, N-A-S-H is the major hydration product. PS is still classified as a material with low pozzolanic activity, as the amount of geopolymer produced in the system is very low. The degree of water-absorption swelling and cracks on the specimen surface induced by the ASR gel deepened with increasing alkali concentration. The involvement of reactive Al and reactive Ca converted the ASR gels into (N,C)-A-S-H gels or C-(A)-S-H gels, which depended on the atomic ratios of these reactive ions, and significantly improved the strength and water resistance of the specimens.

Prediction of Physical and Mechanical Properties of Heat-Treated Wood Based on the Improved Beluga Whale Optimisation Back Propagation (IBWO-BP) Neural Network

The physical and mechanical properties of heat-treated wood are essential factors in assessing its appropriateness for different applications. While back-propagation (BP) neural networks are widely used for predicting wood properties, their accuracy often falls short of expectations. This paper introduces an improved Beluga Whale Optimisation (IBWO)-BP model as a solution to this challenge. We improved the standard Beluga Whale Optimisation (BWO) algorithm in three ways: (1) use Bernoulli chaos mapping to explore the entire search space during population initialization; (2) incorporate the position update formula of the Firefly Algorithm (FA) to improve the position update strategy and convergence speed; (3) apply the opposition-based learning based on the lens imaging (lensOBL) mechanism to the optimal individual, which prevents the algorithm from getting stuck in local optima during each iteration. Subsequently, we adjusted the weights and thresholds of the BP model, deploying the IBWO approach. Ultimately, we employ the IBWO-BP model to predict the swelling and shrinkage ratio of air-dry volume, as well as the modulus of elasticity (MOE) and bending strength (MOR) of heat-treated wood. The benefit of IBWO is demonstrated through comparison with other meta-heuristic algorithms (MHAs). When compared to earlier prediction models, the results revealed that the mean square error (MSE) decreased by 39.7%, the root mean square error (RMSE) by 22.4%, the mean absolute percentage error (MAPE) by 9.8%, the mean absolute error (MAE) by 31.5%, and the standard deviation (STD) by 18.9%. Therefore, this model has excellent generalisation ability and relatively good prediction accuracy.

TUDY OF THE INFLUENCE OF THE ACCUMULATED DOSE OF DAMAGE IN THE NEAR-SURFACE LAYER ON RESISTANCE TO EXTERNAL INFLUENCES ASSOCIATED WITH CORROSION PROCESSES DURING HIGH-TEMPERATURE ANNEALING

Abstract. Investigating the challenges associated with the structural and strength degradation of ceramic fuel cells, which hold significant potential for hydrogen production through electrolysis methods, is a current focus ofresearch. Understanding the degradation processes and their occurrence rate is crucial in the assessment of the efficacy of these ceramics for applications in alternative energy production, specifically in the realm of hydrogen energy. The aim of this study is to ascertain the impact of doping ceramics with aluminum nitride NiAl2O4, irradiated with protons with a dose of approximately 50 dpa, on resistance to high-temperature degradation, and associated corrosive processes of oxidation and swelling, as well as migration processes of implanted hydrogen. Three types of ceramics were selected as objects for study: NiAl2O4ceramics, NiAl2O4ceramics stabilized with 0.05 M AlN, NiAl2O4ceramics stabilized with 0.15 M AlN, that are distinguished by the formation of impurity phases in Al7O3N8, with an orthorhombic type of crystal lattice. As a result of high-temperature tests, it was observed that NiAl2O4ceramics, when stabilized, exhibit reduced susceptibility to destructive alterations in strength characteristics, primarily attributed to the deformation distortion of the crystal structure caused by its swelling. These processes are associated with an augmentation in the thermal expansion of the crystal structure, manifested in the deformation swelling of the crystal lattice volume.