Search Results (499)

Lost circulation in fractured formations remains challenging for oil-based drilling fluids because conventional rigid bridging materials can be sensitive to fracture geometry and form porous seals. In this study, an oil-absorbing swelling gel plugging agent (OSGP) was prepared by water-in-oil emulsion free-radical polymerization. Its oil-induced swelling, strain-dependent viscoelasticity, and bidirectional fracture-sealing behavior were evaluated together with morphology and thermal mass-loss behavior. After 12 h in white oil at 120 °C, the particle volume increased by 19.2%. At 25 °C, OSGP showed an elastic-dominant response with strain-induced softening. In independent fracture-sealing tests at 120 °C, OSGP formed pressure-bearing seals in both 3 mm parallel and 3 mm-to-1 mm wedge-shaped steel fractures, with a maximum forward breakthrough pressure of 8.06 MPa. Comparison of forward and reverse tests showed that fracture geometry and flow direction strongly affected pressure-bearing behavior. The combined results support a proposed sealing process involving particle bridging, oil-induced swelling, deformation, and compaction. OSGP therefore shows potential for further evaluation as a lost-circulation material in fully formulated oil-based drilling fluids and rock fractures. Full article

The escalating environmental burden of conventional plastic food packaging has intensified the search for sustainable, biodegradable alternatives. However, single-component polysaccharide edible films often exhibit suboptimal mechanical and barrier properties, which limits their practical applicability. In this study, pullulan (PUL), konjac glucomannan (KGM) and low-acyl gellan gum (LGG) were blended as film-forming substrates with glycerol as a plasticiser. Single-factor experiments combined with Box–Behnken response surface methodology (RSM) were employed to optimise the formulation of ternary edible composite films. The effects of PUL, KGM and LGG concentrations on mechanical properties and water vapour permeability (WVP) were systematically investigated. The optimised film was comprehensively characterised for microstructure, physical barrier performance, antioxidant activity, soil disintegration, bacteriostatic capacity and plum preservation efficiency. The optimal formulation comprised 1.43 g/100 mL PUL, 0.24 g/100 mL KGM and 0.48 g/100 mL LGG. Under these conditions, the composite film exhibited a transparent and smooth appearance, with a continuous and dense internal microstructure. The comprehensive performance score (K) reached 0.805 ± 0.013, with a WVP of 2.75 ± 0.17 g·μm/(m²·h·kPa), light transmittance of 89.93% ± 1.26%, tensile strength (TS) of 3.05 ± 0.14 N/cm², elongation at break (EB) of 64.57% ± 0.58% and DPPH radical scavenging activity of 34.12% ± 0.96%. Storage trials on two plum varieties demonstrated that the composite coating effectively mitigated fruit weight loss, retarded peel browning and pulp softening, and maintained superior sensory quality throughout storage. Overall, the PUL/KGM/LGG ternary edible composite film exhibited favourable mechanical strength, promising water vapour barrier properties and moderate antioxidant activity, suggesting its potential as a useful reference for the further development and industrial adoption of biodegradable edible films in fruit and vegetable preservation. Full article

Soft fruits are highly perishable due to their delicate surface barriers, rapid cell-wall disassembly, turgor loss, oxidative imbalance, and tightly coordinated ripening and senescence processes that collectively accelerate water loss, softening, and decay after harvest. This review examines how melatonin (MLT) interacts with these deterioration processes in blueberries, raspberries, strawberries, grapes, and sweet cherries. Current evidence identifies redox regulation as the most consistent mechanism of MLT action, including modulation of reactive oxygen species, enhancement of antioxidant enzymes and the ascorbate–glutathione cycle, and maintenance of phenolic and other non-enzymatic antioxidants. These responses are linked with lower lipid peroxidation, reduced membrane leakage, delayed cell-wall degradation, and improved firmness, water retention, and decay resistance. More limited and species-specific evidence suggests that MLT may influence cuticular wax metabolism, endogenous MLT biosynthesis, H₂S signaling, GABA and polyamine metabolism, phenylpropanoid pathways, and host-defense responses. However, direct evidence for effects on cuticular permeability, cellular compartmentation, and hormonal signaling remains limited. Overall, MLT should be regarded as a context-dependent regulator of redox homeostasis, tissue integrity, ripening, and defense rather than as a universal anti-senescence treatment, because its effects vary with species, cultivar, concentration, maturity stage, and storage conditions and still require validation under commercial conditions. Full article

The mechanical properties of moraine soil in cold regions are significantly influenced by freeze–thaw cycles (FTCs). However, current understanding of the quantitative characteristics of its shear behavior under the coupled effect of FTCs and confining pressure is still insufficient. To address this, a series of triaxial unconsolidated-undrained shear tests were conducted on saturated moraine soil, with different numbers of FTCs (N = 0, 1, 4, 8, 10, 12, 15, 20) and various confining pressures (σ₃ = 100, 200, 300, 400 kPa). The experimental results reveal that: (1) With an increase in the number of FTCs, the stress–strain curves gradually change from strain-softening to strain-hardening types. Correspondingly, the pore water pressure development shifts gradually from a peak-decay pattern to a growth-stabilization pattern. The peak pore water pressure rises linearly with increasing confining pressure, whereas it decays linearly with an increasing number of FTCs. (2) Both the secant modulus E₅₀ and the shear strength increase with higher confining pressure and decrease with more FTCs. Confining pressure exerts a significant inhibitory and compensatory effect on freeze–thaw-induced damage, markedly reducing the deterioration rate under high confining pressure. (3) Quantitative prediction models for E₅₀ and q_max were established, effectively capturing the coupled effect of confining pressure and FTCs. It can be inferred that confining pressure mitigates structural damage by compressing frost-induced cracks and enhancing interparticle contacts, while FTCs exacerbate the degradation of soil mechanical properties because of ice crystal expansion or contraction and weakening of cementation. This study quantifies the coupled effect of confining pressure and FTCs, and the proposed prediction model provides a useful reference or preliminary estimation for relevant geotechnical engineering designs. Full article

This study investigates the influence of biomass fly ash (BFA) produced from high-temperature combustion of woody biomass fuels typical of Lithuanian energy plants on the mechanical performance, microstructure, and reactivity of alkali-activated binders based on diatomite and iron dust. Diatomite was used as a reactive silica source, while iron dust served as a matrix-modifying component enhancing binder density and strength. The role of BFA (10–30%) was evaluated in terms of compressive strength, softening factor, water resistance, and structural development using XRD and FTIR analyses. The results show that the formation of a compact geopolymer gel is the key factor controlling strength development. The highest compressive strength (53 MPa) was obtained at 10% BFA; however, it decreased to 33 MPa after thermal treatment at 200 °C, indicating limited structural stability. Increasing the BFA content to 20% and 30% improved the softening factor and water resistance but significantly reduced compressive strength to below 20 MPa and 10 MPa, respectively, demonstrating a trade-off between strength and durability. XRD analysis confirmed similar mineralogical compositions in all samples, dominated by largely unreacted quartz and magnetite, while minor amounts of andradite formed after thermal treatment. FTIR results revealed increased polymerisation with higher BFA content, reflected by the shift of the Si–O–T band (~966–985 cm⁻¹ to ~988–995 cm⁻¹), although the presence of Ca-rich and partially unreacted phases led to a less efficient geopolymeric network. Overall, the performance of the studied systems is governed by the balance between gel formation, phase composition, and microstructural integrity, with optimal properties achieved at moderate BFA content rather than at extreme compositions. Full article

Slopes excavated in coal-measure strata are prone to rainfall-induced landslides because water-induced disturbances progressively degrade rock-mass shear strength. This study investigated six coal-measure lithologies from the unloading zone of the Fushun West Open-Pit Mine using triaxial compression tests after separate wetting–drying and continuous-immersion treatments. Condition-dependent cohesion, c, and internal friction angle, φ, were fitted with exponential functions and incorporated into the Mohr–Coulomb criterion. For scenario analysis, the retention ratios measured in the two separate treatment series were applied sequentially in a separable empirical parameterization. This no-interaction approximation was used to update coal-measure strength inputs in representative slope models. Cohesion and φ decreased exponentially within the tested ranges, with in-sample R² values greater than 0.85, and cohesion was generally more sensitive. Continuous immersion produced rapid early softening, whereas wetting–drying cycles produced cumulative deterioration. Limit-equilibrium and finite-element calculations showed lower safety factors and more concentrated deformation under more severe parameter-reduction scenarios. Model-specific cumulative-displacement reference values of 52.36–213.82 mm were paired with Fs levels of approximately 1.15, 1.05, and 1.00 and compared qualitatively with historical monitoring curves. The findings provide a reference for rainy-season slope-stability prediction and staged warning in open-pit coal mines. Full article

Water treatment systems based on sodium–cation exchange are widely used at thermal power plants. However, their operation is associated with high consumption of water and sodium chloride during regeneration and the generation of highly mineralized wastewater. This study proposes an integrated approach to improving the performance of sodium–cation exchange water treatment systems by combining regeneration wastewater recycling with optimization of filter operating conditions. Experimental investigations were carried out to evaluate regeneration wastewater composition, changes in chloride concentration and total hardness during filter washing, and the efficiency of soda-lime softening for subsequent reuse of the treated solution in a closed regeneration cycle. A mathematical method describing concentration-front propagation within the ion-exchange bed under non-equilibrium conditions was developed to determine the actual working capacity of the resin and predict filter cycle duration at different filtration rates. The model was verified against experimental data and implemented as software for automated calculation of operating parameters. The proposed closed-loop regeneration scheme enables reuse of treated regeneration solutions, reduces sodium chloride consumption, and decreases the discharge of highly mineralized wastewater. The developed calculation method provides a basis for selecting rational operating conditions, improving utilization of ion-exchange resin capacity, and reducing water and reagent consumption. The combined application of wastewater recycling technology and the proposed calculation approach improves the operational, economic, and environmental performance of water treatment systems at thermal power plants. In this paper, the presented calculations are combined with experimental characterization and treatment of regeneration wastewater with soda and lime, selective extraction of concentrated regeneration fractions, their return to the regeneration cycle, and the selection of operating conditions based on calculations within a unified resource-efficient water treatment scheme. The integrated assessment of filter performance with treatment and reuse of regeneration wastewater is the novelty of this study. Full article

Dispersive soils are widely distributed in the seasonally frozen regions of northeastern China, where hydrothermal dynamics driven by seasonal freeze–thaw (FT) cycles dominate the hydrological evolution and mechanical deterioration of soil masses, posing a serious threat to the long-term stability of hydraulic engineering in cold regions. However, the hydro–thermo–mechanical (HTM) coupled degradation mechanisms of dispersive clay from the South Nenjiang Main Canal remain poorly understood, particularly the linkage between FT-induced microstructural evolution and macroscopic mechanical behavior. In this study, low-plasticity dispersive clay specimens were subjected to 0–12 FT cycles. Unconsolidated undrained (UU) triaxial tests were conducted to evaluate mechanical behavior, while scanning electron microscopy (SEM) combined with the Pore and Crack Analysis System (PCAS) was used to quantify microstructural evolution. Results indicated that increasing FT cycles transformed the stress–strain response from mild strain-softening to strain-hardening, with the failure mode evolving toward bulging-type ductile failure. Cohesion exhibited a pronounced exponential decay, with the most significant degradation occurring within the first three FT cycles and stabilizing after approximately six FT cycles, whereas the internal friction angle showed only minor variation. At the microscale, porosity and total pore area increased continuously through micropore coalescence and macropore development, with a slight decrease in fractal dimension indicating reduced pore boundary complexity and smoothed pore interfaces due to frost heave-induced pore merging. The FT-induced hydrothermal disturbance promoted pore-water phase transition and redistribution, resulting in progressive pore enlargement and loss of structural integrity. Because the specimens were tested in sealed, closed-system conditions with a nearly constant total water content, this degradation chain is attributable specifically to in situ ice–water phase transitions and internal pore-water redistribution, i.e., water-phase-change-driven processes, rather than to external water supply. It is demonstrated that interparticle bond breakage and pore expansion–coalescence driven by ice–water phase transitions dominate strength degradation, promoting a transition from structure-dominated to friction-dominated strength behavior. A normalized cohesion reduction factor and a cohesion degradation index are further proposed to quantify the progressive loss of structural integrity and to provide a design-oriented tool for cold-region geotechnical practice. These findings provide a basis for stability assessment and hazard mitigation of dispersive soils in cold-region engineering. Full article

The compaction deformation and load-bearing behavior of crushed gangue in the caved zone of goafs directly affect overburden movement, fracture evolution, and stability evolution. To clarify the compaction deformation mechanism of crushed gangue under wetting conditions in goafs, confined compression tests coupled with synchronous acoustic emission (AE) monitoring were carried out. Sandstone and mudstone crushed gangue were selected as the research objects, and Talbot gradation indexes of $n$ = 0.2, 0.4, 0.6, and 0.8 were adopted. The effects of lithology, particle gradation, and moisture condition on compaction deformation, particle-structure adjustment, and AE response were systematically analyzed under dry and short-term wetting conditions. The results show that: (1) the confined compression process of crushed gangue exhibits pronounced nonlinear strain-hardening behavior and can be divided into rapid compaction, slow compaction, and stable compaction stages. Water dripping shifts the stress–strain curves toward the higher-strain side and significantly enhances the compression deformation of mudstone, indicating a stronger wetting response of mudstone than sandstone. Meanwhile, water dripping reduces the equivalent compressive stiffness of crushed gangue. (2) Particle gradation affects the compaction response by modifying the proportions of coarse and fine particles and the initial pore structure. With increasing Talbot gradation index $n$, the proportion of coarse particles increases, resulting in more pronounced skeleton collapse, localized particle breakage, and secondary filling by fine particles, and the final compression deformation generally increases. After wetting, the final strain of mudstone samples with different gradations concentrates within 0.32035–0.33439, indicating that the control of water-induced softening on mudstone compaction deformation is stronger than the gradation effect. (3) AE results indicate that the compaction process of broken rock can be divided into a flow sliding deformation stage, a fracture deformation filling stage, and a compaction elastic deformation stage, corresponding, respectively, to particle sliding and rearrangement, particle breakage and pore filling, and structural stabilization and consolidation. Water action affects damage evolution by modifying particle contact conditions, promoting fine-particle migration, and facilitating structural adjustment. Among them, mudstone exhibits a more pronounced wetting response, whereas sandstone maintains relatively higher structural stability. The findings provide a reference for analyzing overburden movement, predicting residual subsidence, and evaluating stability in water-influenced goafs. Full article

Konjac glucomannan (KGM), a natural hydrocolloid, is often recognized as an effective texturizing and stabilizing agent in flour-based products. This study systematically investigated the effects of KGM on wheat starch molecules and the gluten protein network. The results showed that different substitution levels (0–5%) of KGM influenced the gelatinization process of starch granules through a thickening effect and competitive hydration. This was specifically manifested as an increase in the pasting viscosity and gelatinization temperature of the system, along with a decrease in gelatinization enthalpy. For textural properties, the KGM addition reduced the hardness of wheat flour gels while enhancing their adhesiveness. Within the dough system, KGM significantly enhanced the gluten network stability, supported by increased water absorption and dough stability time, and decreased degree of softening. Meanwhile, the incorporation of KGM increased the tensile resistance of the dough but decreased the maximum elongation ratio. Furthermore, the storage modulus and loss modulus of the dough showed an increasing trend with higher KGM concentrations. In conclusion, KGM significantly influenced the physicochemical properties and final processing quality of the dough by binding with starch, cross-linking gluten networks, and altering water distribution. This study offered a theoretical foundation for KGM applications in optimizing flour-based product quality. Full article

An urgent necessity exists to create foods that cater to the requirements of patients with dysphagia. The softened surimi gel appropriate for dysphagia patients was produced through ultrasonic-assisted Protein-glutaminase (PG) deamidation treatment. In comparison to the control group, the hardness and gel strength of softened surimi gel with a 0.2% PG addition diminished from 607.40 g and 530.79 g mm to 244.60 g and 78.61 g mm, respectively, satisfying the IDDSI Level 5 classification criteria (p < 0.05). The incorporation of PG transformed free water in the fish paste gel into less mobile water, markedly improving the gel’s water holding capacity. The ultrasound-assisted enzymatic deamidation treatment made the surimi gel produce more small molecular peptides and free amino acids during digestion. This treatment diminished hydrophobic interactions in myofibrillar protein gel, augmented hydrogen bonding, elevated the α-helix structure to 46.27%, and decreased the β-sheet structure to 19.18%, with significant differences compared to the control group (p < 0.05). The polarity of the tryptophan residue microenvironment alters and impeding the further folding of unfolded protein structures during heat-induced gelation. This study offers a fundamental theoretical framework for the development of specialized foods that possess safe swallowing and nutritional attributes. Full article

Coal gangue (CG) backfill, utilizing magnesium slag as a cost-effective alternative to ordinary Portland cement, represents a critical technology for underground waste management in China. Crucially, the confined compressibility of this matrix governs its long-term deformation resistance. However, since CG is enriched with hydrophilic clay minerals that trigger intense water uptake, the compressibility of this weakly cemented backfill is highly susceptible to deterioration under the pervasive high-humidity conditions of underground coal mines, which remains poorly understood. To address this gap, this study investigated the multi-scale confined compression behavior of magnesium slag-based (MPB) and conventional cement-based (CPB) fine CG aggregate backfill cured under a high-humidity environment. One-dimensional confined compression tests using a triple-lever oedometer and scanning electron microscopy (SEM) observations were integrated across varied curing ages. The results indicate that the macroscopic confined compression response is governed by the coupling effects of the moisture-induced softening of fine CG aggregates and the progressive evolution of hydration minerals. With prolonged curing, increased moisture absorption elevates the void ratio variation and compression index (C_c), thereby increasing matrix compressibility. The post-yield C_c after the bond breaks increases with the higher binder content because abundant hydration products encapsulate aggregates, which undergo catastrophic shearing after the cement bond breaks. Conversely, the consolidation coefficient continuously decreases under advancing loads as matrices densify. Although CPB consistently maintains lower compressibility than MPB, both backfills exhibit a time-dependent decline in the yield stress of the cement bond under high-humidity curing. These macro-mechanical degradations are supported by SEM observations; the experimental accuracy was validated through benchmark tests on standard quartz sand. Full article

The shear behavior of loess is closely linked to its microstructural evolution, and understanding this relationship is essential for deciphering the mechanisms of loess hazards. In this study, consolidated-drained (CD) triaxial tests were conducted on intact Q₃ Malan loess from the Dongzhi tableland, China, under varying water contents and confining pressures. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) analyses were performed on specimens before and after shearing to quantitatively and qualitatively characterize the changes in pore and particle properties and their connection to shear deformation. The results reveal three failure modes, including shear, homogeneous, and plastic failure. They are governed by the combined effects of microstructural variation and microcrack development, depending on confining pressure and water content. Quantitatively, as water content increases from 9% to 20%, cohesion decreases by 86.8% and peak shear strength reduces by 68.4%, while the internal friction angle decreases only slightly. Water-induced strength deterioration is governed primarily by cohesion loss rather than friction angle reduction. Thus, 20% water content was identified as the critical threshold marking the transition from cohesion-dominated to friction-dominated strength degradation. A critical threshold at approximately 27% water content is identified, beyond which about 70% of mesopore and macropore volumes undergo collapse, after which the strength is almost entirely sustained by interparticle friction. Based on these findings, the water-induced strength decay mechanism is categorized into three stages: rapid cement degradation, friction-dominated transition, and slow attenuation. These macroscopic phenomena are closely linked to the continuous adjustment of the microstructure, manifested by the softening, dispersion, and disintegration of cementations, particle movement and rearrangement, and the reduction and mutual transformation of inter-aggregate pores under loading and wetting. The three-stage mechanism and threshold characteristics of loess strength degradation upon wetting revealed in this study can provide theoretical support for early slope-instability warning in loess irrigation and heavy rainfall regions, as well as engineering reinforcement prioritizing the recovery of cohesion. Full article

Nickel release from metallic items is the leading cause of allergic contact dermatitis, and preventive strategies require both reliable detection tools and materials capable of limiting skin exposure. In this work, we propose dual-function bioplastic coatings based on starch, glycerol, and cellulose derivatives incorporating dimethylglyoxime (DMG) and a pH-10 borate buffer to enable colorimetric nickel sensing directly in the solid state. The Ni–DMG assay was first optimized in solution through UV-Vis spectroscopy and a Central Composite Face-Centered Design, identifying reagent concentrations that maximize linearity while minimizing detection limits. These conditions were transferred to bioplastic films prepared using carboxymethyl cellulose (CMC) or quaternized hydroxyethyl cellulose ethoxylate (QHECE). The materials were characterized by FT-IR spectroscopy and Principal Component Analysis, while gravimetric tests assessed hydrophilicity. Both bioplastics showed clear and reproducible colorimetric responses upon nickel exposure, and multivariate models built from RGB values and UV-Vis spectra enabled quantitative prediction of Ni²⁺ content. However, the proof-of-concept experiment revealed insufficient resistance to prolonged moisture, with films softening and partially losing cohesion under conditions mimicking skin perspiration. These results demonstrate that the sensing mechanism is robust, but the current bioplastic formulation requires improved water resistance before practical deployment as protective coatings for jewelry. Full article

Fever-range hyperthermia (38–41 °C) is a typical physiological response to infection, inflammation, and systemic stress. Although increased temperatures are known to affect blood rheology and erythrocyte activity, their comprehensive impact on red blood cell (RBC) structure, mechanics, and lifespan remains incompletely understood. This review summarizes current understanding of how moderate hyperthermia affects RBC membrane structure, internal behavior, mechanical properties, and clearance cues. Evidence shows that brief exposure to febrile temperatures primarily induces reversible biophysical modifications, including heightened membrane fluidity, increased membrane fluctuations, changes in hemoglobin–water interactions, and short-term improvements in deformability. These changes reflect adaptive adjustments within the membrane–cytosol–cytoskeleton system, potentially temporarily boosting microcirculatory flow. On the other hand, prolonged or repeated heat stress causes oxidative damage, hemoglobin auto-oxidation, accumulation of membrane-bound hemoglobin, band 3 clustering, cytoskeletal restructuring, calcium imbalance, and disruption of membrane lipid asymmetry. These effects weaken membrane stability and lead to vesiculation, shape changes, increased cell fragility, altered aggregation, enhanced adhesion, and activation of clearance mechanisms. A primary focus is the transition from reversible membrane softening to permanent structural damage over time. The research supports a model in which temperature affects RBC mechanics and related membrane, cytosolic, and signaling processes that influence RBC viability. We propose interpreting febrile hyperthermia as a dynamic factor that shifts RBCs from an adaptive phase to accelerated aging and removal during prolonged heat exposure. This perspective enhances our understanding of RBC behavior during fever and systemic inflammation and underscores the role of temperature in shaping erythrocyte function and lifespan. Full article