The study utilized litchi shells as precursors to synthesize N, S self-doped carbon quantum dots (LBCQDs) by a hydrothermal method for use as corrosion inhibitors. Electrochemical testing, weight loss tests, surface characterization, and density functional theory calculations were employed to investigate the corrosion inhibition performance of LBCQDs on 5052 aluminum alloy in the HCl solution. The results indicate that LBCQDs are a mixed-type corrosion inhibitor, predominantly inhibiting cathodic reactions. Their corrosion inhibition efficiency increases with concentration, reaching a maximum of 94.22% at a concentration of 300 mg·L-1. In addition, higher concentrations of LBCQDs result in a slower reduction in corrosion inhibition efficiency over a prolonged immersion time. The corrosion inhibition mechanism analysis indicates that LBCQDs can spontaneously form a protective film on the aluminum alloy surface based on the synergistic effects of physical adsorption, chemical adsorption, aggregation effect, and the chelation reaction. This increases the energy barrier of the corrosion reaction of the aluminum alloy, thereby inhibiting corrosion. This work not only provides a high-value utilization strategy for litchi shell biomass but also offers profound insights for designing eco-friendly corrosion inhibitors.

This research employed biomass orange peel as a precursor to synthesize N, S, P heteroatom self-doped carbon quantum dots (N, S, P-BCQDs) via hydrothermal treatment for use as corrosion inhibitors. The inhibitory effectiveness of N, S, P-BCQDs on 7A04 aluminum alloy in HCl solution was evaluated by electrochemical analysis, weight loss test, surface characterization, and density functional theory (DFT) simulations. The findings demonstrate that N, S, P-BCQDs act as mixed-type inhibitors, predominantly suppressing cathodic reactions. The corrosion inhibition efficiencies increase with concentration, reaching a maximum of 93.07% at 150 mg L-1. Furthermore, the higher the concentration of N, S, P-BCQDs, the slower the decrease in corrosion inhibition efficiency with the extension of immersion time. Analysis of the corrosion inhibition mechanism indicates that N, S, P-BCQDs can spontaneously form a thick and stable protective film on the surface of aluminum alloys through multiple interactions, including physical adsorption, chemical adsorption, aggregation effects and chelation reactions. This film elevates the energy barrier for corrosion reactions, effectively suppressing the corrosion process. This work reveals the significant potential of biomass-derived heteroatom self-doped carbon quantum dots for advanced anticorrosion applications.

The scarcity of road construction materials in arid desert areas necessitates the utilization of local resources to ensure sustainable infrastructure development. This study investigates the durability and damage evolution of a semi-rigid base material composed of Cement-Fly Ash Stabilized Gravel with 100% aeolian sand replacement for fine aggregates (CFSAG). The mechanical performance was evaluated under simulated desert environments, including high-temperature curing (30 °C, 40 °C, and 50 °C) and freeze–thaw cycles in both water and 2% Na₂SO₄ solution. Additionally, Digital Image Correlation (DIC) technology was employed to characterize the microscopic strain fields and crack propagation patterns. The results indicate that elevated curing temperatures significantly enhance compressive strength, with 40 °C identified as the optimal condition for strength formation due to accelerated hydration. Conversely, resistance to freeze–thaw cycles decreased with higher aeolian sand content, and sulfate erosion accelerated surface spalling, causing the specimen mass to exhibit an "increase-then-decrease" trend. A strength evolution model was established based on freeze–thaw frequency and mix proportions, achieving a fitting accuracy of over 98%. Furthermore, DIC revealed that the strain and displacement variations during crack propagation in specimens exhibited a three-stage evolutionary pattern, with strain localization bands becoming more pronounced as compaction decreases. The study concludes that CFSAG is a feasible, durable, and eco-friendly solution for semi-rigid pavement bases in desert regions.

The mechanistic link between heat treatment-induced microstructural modifications and the protectiveness of rust layers remains a critical knowledge gap in marine corrosion of low-alloy steels. This study systematically investigated the corrosion behavior of AISI 8630M steel under as-received and quenched-tempered (Q&T) conditions in simulated seawater. Electrochemical measurements and equivalent circuit modeling revealed that Q&T treatment enhanced charge transfer resistance by 4.46-fold and reduced corrosion current density by 41.94%, attributed to microstructural homogenization. Time-sequenced immersion experiments (21 and 35 days) combined with XRD, XPS, and KPFM characterization revealed that the Q&T processing significantly accelerated the phase transformation kinetics within the rust layer. It led to a consistently higher alpha-FeOOH/ gamma-FeOOH ratio (reaching 0.84 vs. 0.62 in the as-received steel) by promoting the rapid formation and dominance of the thermodynamically stable alpha-phase, which underpinned its superior barrier properties. Molecular dynamics simulations elucidated that alpha-FeOOH exhibits 11.5% lower Cl- binding energy compared to gamma-FeOOH, thereby inhibiting aggressive ion penetration. This work establishes a quantitative multi-scale framework linking heat treatment parameters to protective rust layer engineering, providing mechanistic insights for optimizing corrosion-resistant steel alloys for harsh marine environments.

The Cr-Co-Ni particle-reinforced AZ31 magnesium matrix composite (CrCoNi/AZ31) was manufactured by powder metallurgy. Through the use of microscopic analysis, the emergence of the new Al13Cr2 phase within the composite material was observed. The hot deformation characteristics of the CrCoNi/AZ31 magnesium matrix composites were examined with hot compression testing. The experimental parameters were established within the temperature range of 250-400 degrees C and the strain rate range of 0.001-1 s-1. The analysis focused on the flow stress and micro-deformation mechanisms of the CrCoNi/AZ31 magnesium matrix composites during the hot deformation. The constitutive equation model was developed for the CrCoNi/AZ31 magnesium matrix composites. The hot deformation activation energy Q was calculated to be 137.06 kJ/mol based on this model. The correlation coefficient between the constitutive model and the experimental data was determined to be R2 = 0.9608. The processing map for the CrCoNi/AZ31 magnesium matrix composites was created. The optimal deformation conditions for the CrCoNi/AZ31 magnesium matrix composites were identified as follows: the deformation temperature of 350-400 degrees C and strain rate of 0.001-0.01 s-1. During the hot compression process, continuous dynamic recrystallization (CDRX) is the primary recrystallization mechanism. The Al13Cr2 phase promotes dislocation accumulation, triggers the particle-stimulated nucleation (PSN) mechanism, and creates particle deformation zones (PDZs), accelerating the dynamic recrystallization process and thereby enhancing the microstructural uniformity of the composite material.

In this study, the effects of Cu and Zn addition on the microstructure, mechanical properties, and intergranular corrosion (IGC) resistance of Al-5.5Mg alloys are examined. With increasing Cu addition in as-cast alloy, the primary phases change from lamellar T-Al6Mg4Cu phase to blocky S-Al2CuMg and T-Al6Mg4Cu phases, which are reticulately distributed alongside grain boundaries. The lump T-Mg32(Al, Zn)49 phase is formed by introducing Zn. In Cu-containing alloys, the mechanical properties are optimal for the alloy with 1.5 wt

This study prepared N-doped carbon dots (N-CDs) as an inhibitor by employing citric acid and ethylenediamine as precursors via a hydrothermal method. The corrosion inhibition behavior of N-CDs on X65 steel and 7A04 aluminum alloy in HCl solution was systematically studied and compared using electrochemical measurements, weight loss test and surface analysis techniques. The results indicate that the synthesized N-CDs function as mixed-type inhibitors primarily inhibiting the anodic reaction, and they exhibit better corrosion inhibition performance on X65 steel compared to 7A04 aluminum alloy. The corrosion inhibition efficiencies of N-CDs increase and then decrease with concentration, and the extreme-value-phenomena of concentration appears at 100 mg/L, which is related to the stability and agglomeration degree of N-CDs in the solution. In addition, this study also compares and analyzes the corrosion inhibition mechanisms of N-CDs for both types of metals in HCl solution.

High-ground stress soft rock tunnels have experienced large deformations. Yielding and pressure relief fluid-filled lining support technology is an effective method for solving large soft rock tunnel deformation due to the deformation characteristics of high-ground stress soft rock tunnels. To give the surrounding rock a certain amount of deformation space, a layer of fluid filling is set up at the reserved deformation of the tunnel. By creating a force test model of the inflatable carcass and water-filled carcass, the straight section of the tunnel support structure is simulated. When supporting large deformation soft rock tunnels, inflatable and water-filled carcasses produce fluid homogenization load shedding and fluid drainage load shedding effects. Inflatable carcasses and water-filled carcasses without leakage reduce load by about 28% and 7%, respectively. The peak load reduction rate under liquid leakage can gradually reach 100 %. Inflatable carcasses can dissipate up to 90% of the work of external forces acting on the supporting structure. The load reduction rate of water-filled carcass is 1.2 times that of inflatable carcass. Fluid-filled materials can remove load from secondary lining support structures after yielding and pressure relief. Design and construction of high-ground stress soft rock tunnels can be influenced by research results.

Avalanche susceptibility assessment is a core aspect of regional avalanche early warning and risk analysis and is of great significance for disaster prevention and mitigation on proposed highways. Using sky–ground integration investigation, 83 avalanche points within the G219 Wen Quan to Horgos transportation corridor were identified, and the avalanche hazard susceptibility of the transportation corridor was partitioned using the certainty factor (CF) model and the coupled coefficient of the certainty factor–Geodetector (CF-GD) model. The CF model analysis presented nine elements of natural conditions which influence avalanche development; then, by applying the Geodetector for each of the factors, a weighting coefficient was given depending on its importance for avalanche occurrence. The results demonstrate the following: (1) According to the receiver operating characteristic (ROC) curve used to verify the accuracy, the area under the ROC curve (AUC) value for the CF-GD coupled model is 0.889, which is better than the value of 0.836 of the CF model’s evaluation accuracy, and the coupled model improves the accuracy by about 6.34% compared with the single model, indicating that the coupled model is more accurate. The results provide avalanche prevention and control recommendations for the G219 Wen Quan to Horgos transportation corridor. (2) The slope orientation, slope gradient, and mean winter temperature gradient are the main factors for avalanche development in the study area. (3) The results were validated based on the AUC values. The AUCs of the CF-GD coupled model and the CF model were 0.889 and 0.836, respectively. The accuracy of the coupled model was improved by about 6.34% compared to the single model, and the coupled CF-GD model was more accurate. The results provide avalanche control recommendations for the G219 Wen Quan to Horgos transportation corridor.

Functional groups of organic molecules play their respective advantages in the Zn deposition process, thus bringing significant improvements to the electrochemical performance even at trace additions. In this study, we introduced adenosine (ADS) bio-organic molecules into electrolyte to facilitate the uniform diffusion of Zn2+ and enable the in-situ construction of a zincophilic anode/electrolyte interface by preferential chemisorption of the ADS-amino group on the Zn anode. Automatically, the ADS-hydroxyl group towards the electrolyte bulk will coordinate free water molecules through hydrogen bonding, accelerating the process of Zn2+ extraction from the solvation structure. This interface not only has a strong affinity for promoting Zn2+ dynamic transport and uniform deposition but also acts as a suppressor for side reactions. Consequently, Zn||Zn symmetric cells with a trace amount of ADS additive (5 mM) exhibit an ultra-long lifespan of 3000 h at 2 mA cm−2 and 2 mAh cm−2 and 950 h at a harsh condition of 8.85 mA cm−2 and 8.85 mAh cm−2. A practical rechargeable Zn||NVO pouch cell is assembled, showing a capacity of 140 mAh g−1 and remarkable stability of 96 % retention for 300 cycles at 0.5 A g−1.

Auto-ignition triggering plays an important role in the study of knock, accurate and generalized calculation methods are of great significance. In this study, a brand new calculation method of end-mixture auto-ignition timing based on heat release rate (HRR) is proposed based on several sets of data with different knock intensities of a small turbocharged gasoline engine. The calculation method effectively eliminates the effect of fluctuations in the actual HRR data by setting the search range and the auto-ignition threshold, and also eliminates the calculation delay caused by the second-order derivatives of HRR in the regular calculation method. Under this calculation method, the auto-ignition and knock characteristics present a good fit. The effects of combustion parameters on auto-ignition are significantly different. The changes in engine coolant and inlet air temperature as well as the over-rich mixture significantly affected the auto-ignition trigger pressure, while the ignition timing and the over-lean mixture had no effect on it. The effects of methanol on auto-ignition trigger pressure were also significantly different under various injection timings. The calculation of auto-ignition timing provides a vital prerequisite for the study of auto-ignition triggering, which is of obvious significance for the study of knock.

Mild steel corrosion is a significant challenge in oil and gas exploitation. Inhibitors are frequently employed to minimize the corrosive impact on mild steel. Mixing corrosion inhibitors is an effective method in reducing the dosage of toxic compounds and expanding the potential applications of inhibitors in NaCl solutions. Herein, a mixed corrosion inhibitor composed of imidazoline (IM), sodium molybdate, and sodium dodecylbenzenesulfonate (SDBS) for mild steel in a 3.5 wt% NaCl solution are investigated by orthogonal experimental design and electrochemical measurement. The imidazoline compound was synthesized and identified using Fourier transform infrared (FTIR) spectroscopy. The inhibitory effect is improved by higher concentrations of sodium molybdate and is further enhanced with the addition of 10 mg/L of SDBS. The electrochemical impedance spectroscopy indicates that the combination of IM (100 mg/L), sodium molybdate (50 mg/L), and SDBS (100 mg/L) results in excellent performance with electrochemical impedance (1.8 kohm·cm2). The mild steel surfaces after electrochemical measurement were analyzed using scanning electron microscopy (SEM). The information can contribute to the development of corrosion inhibitors with high performance or to understand the influence of mixing inhibitors on corrosion processes of mild steels.

This work was carried out as the Pakistani, Uzbekistani, Tajikistani, and Kyrgyzstani contribution to the National-scale Geochemical Survey of South and Central Asia (NGSSCA) project, the objective of which was to document and study the amounts and distribution of chemical elements in stream sediment of South and Central Asia where such national-scale geochemical mapping is launched for the first time. In the framework of the NGSSCA project deployed in Pakistan, Uzbekistan, Tajikistan, and Kyrgyzstan, 9237 stream sediment samples (<2 mm grain-size fraction in alpine desert and mountainous area) were collected at an average density of 1 sample site/100 km2, on the basis of a common stream sediment sampling protocol. The resultant compositional data sets and cartographic products will vastly benefit future mineral exploration activity, surficial (and even solid Earth) geochemical processes studies (e.g., chemical weathering), and environmental evaluation. Eight elements of economic interests (e.g., Ag, Sb, W, Mo, Li, Be, Cu, and Co) are selected to demonstrate their distribution pattern in stream sediment and the main controlling factors. It's concluded that the anomalies for the selected elements in the NGSSCA project can thus be directly linked to different geogenic sources, e.g., underlying bedrock, soil type, mineralization or ore deposits, and large-scale fault systems. Based on the results and the integrated anomaly maps, some new target areas for the corresponding metallic mineralization are predicted, which will provide a basis for further mineral exploration.

This paper investigated the influence of ultraviolet (UV) illumination on the corrosion behavior of 7A04 aluminum alloy in 3.5% NaCl solutions with various pH values (pH=5.0, 7.0, and 10.0) using weight loss measurement, electrochemical methods, and surface analysis techniques. The research results indicated that the corrosion products of 7A04 alloy in salt solutions with different pH values all exhibited n-type semiconductor properties and could trigger the photovoltaic effect under UV illumination. Simultaneously, UV illumination reduced the compactness of the corrosion products, inhibited the enrichment of copper compounds (Cu2O), and promoted the generation of hydroxyl radicals in the solution. Therefore, UV illumination significantly accelerated the corrosion process of 7A04 alloy, with the overall acceleration effect ranking as follows: alkaline > neutral > acidic. In addition, the corrosion mechanism of 7A04 alloy in the test solutions with and without UV illumination was also discussed in this paper.

The waterline corrosion behaviors of carbon steel covered by organic coating with artificial defects at and under the waterline simultaneously in simulated artificial seawater were studied by the wire beam electrode (WBE) and electrochemical impedance spectroscopy (EIS) technologies. It was first proposed that the corrosion process of the metal substrate covered by organic coating under the waterline was mainly divided into three stages: no significant corrosion reactions of the metal substrate occurred; the cathodic reaction occurred with relatively slight corrosion on the metal substrate; cathodic delamination of the coating occurred, and the metal substrate was further corroded. Due to the different concentrations of dissolved oxygen, the corrosion reactions of the two exposed electrodes at the waterline and under the waterline were dominated by cathodic and anodic reactions, respectively. For the electrodes under the waterline, on account of the anodic dissolution reaction of the metal substrate, the cathode to anode polarity reversal occurred. In addition, for the yellow corrosion products, the main components were alpha - Fe2O3, beta - FeOOH and gamma - FeOOH, while alpha - Fe2O3 and Fe3O4 were the main components of the black corrosion products. gamma - FeOOH participated in the cathodic reaction to form Fe3O4, which resulted in the reduction of the anodic current density at the electrode surface.

This investigation delves into the thermal deformation behavior of TC9 titanium alloy. Compression tests at isothermal conditions were performed on a Gleeble thermal simulator under conditions spanning 700-1200 degrees C and strain rates of 0.001-1 s- 1. The true stress-true strain curves indicated that stress increases with rising strain rate and decreasing temperatures. The softening mechanisms in the biphasic and monophasic regions were discussed. By correcting errors caused by friction, the strain-compensated Arrhenius-type constitutive equation, which accurately describes the flow behavior of TC9 titanium alloy, has been established. A processing map at a strain of 0.7 was constructed based on the power dissipation factor, revealing an unstable region at 700-800 degrees C/ 0.01-1 s-1 and 800-900 degrees C/0.1-1 s-1, where microcrack defects were observed, suggesting that processing should be avoided in this region. Efficiency values as high as 60-70 % indicate superplasticity deformation, with corresponding m values within this efficiency range of approximately 0.4-0.5, reaching the strain rate sensitivity index range of superplasticity titanium alloys. Tensile tests conducted at 900 degrees C and a deformation rate of 0.001 s-1 showed elongation exceeding 100 %. The sample compressed at 900 degrees C and 0.001 s-1 exhibits small grain size, uniform orientation, the lowest dislocation density, and a uniform two-phase mixture. These microstructural features indicate the material's good machinability.

In this study, five kinds of 1-alkyl-3-methylimidazolium bromide ([CXami]Br) ionic liquids with different alkyl chain lengths (8, 10, 12, 14, and 16) were selected as inhibitors. Then, their corrosion inhibition performances for Q235 steel in 1.0 mol L-1 HCl solution were investigated via a weight loss test, polarization curve method, and surface analysis techniques. The results show that these five imidazolium-based ionic liquids are all mixed-type inhibitors, and they can be spontaneously adsorbed onto the Q235 steel surface. The adsorption process follows the Langmuir model and involves mixed physical-chemical adsorption. Theoretical calculations confirm that the increase in alkyl chain length is conducive to the imidazolium-based ionic liquids exhibiting stronger chemical bonding abilities and forming denser adsorption films. The inhibition efficiency significantly increases below the critical micelle concentration (CMC) with an increase in alkyl chain length, and the highest inhibition efficiency is 95.17% for the [C16ami]Br inhibitor at the concentration of 0.005 mM. However, above the CMC, the inhibition efficiency is minimally affected by the alkyl chain length since all ionic liquid inhibitors have reached adsorption saturation on the steel surface.

Aluminum alloy structural materials are widely subjected to the interactive effect of atmospheric corrosion under thin liquid film and elastic stress during the actual service. This study utilized the real marine atmospheric environment as the corrosion environment of thin liquid film for 7A04 aluminum alloy, and the specially designed outdoor device was used to apply varying levels of static elastic tensile stress at the same time, and then the corrosion damage behavior of 7A04 alloy under the interactive effect was studied. The research indicates that the 7A04 alloy suffers from pitting and exfoliation corrosion under the test conditions. The applied elastic tensile stress can accelerate the corrosion damage process of 7A04 alloy, and the degree of acceleration increases with increasing stress levels and exposure time. Moreover, the applied stress can also significantly accelerate the deterioration of the mechanical properties of 7A04 alloy, which has a more prominent effect on the elongation after fracture. Additionally, the corrosion mechanism of 7A04 alloy under the interactive effect was also discussed in this paper.

This study examined 2-phenyl imidazoline (2-PI) as an eco-friendly corrosion inhibitor for Q235 and X65 steels with various microstructures in CO2-saturated solution. The inhibition performances of the 2-PI inhibitor for both steels were comparatively studied through electrochemical tests, weight-loss method, wire beam electrode (WBE) technique as well as surface analysis. The results demonstrate that the 2-PI compound acts as a mixed-type inhibitor and exhibits effective and durable inhibition performance against general and localized corrosion. The adsorption of 2-PI molecules on steel surfaces is exothermic, spontaneous and follows the Langmuir isotherm model. Furthermore, the steel microstructure strongly influences the adsorption behavior of 2-PI inhibitor, the Q235 steel with a higher pearlite/ferrite ratio promotes the physical adsorption of the protonated 2-PI molecules at lower concentrations, and the X65 steel with a lower pearlite/ferrite ratio enhances the chemical adsorption of the unprotonated 2-PI molecules at higher concentrations. Additionally, the adsorption mechanism was also discussed based on the evaluated thermodynamic data and the results of X-ray photoelectron spectroscopy (XPS) analysis.

At present, the common protection technology of power-transmission and transformation equipment is mainly coating protection and hot-dip zinc protection. However, due to the low adhesion of epoxy zinc-rich coating, and the poor compatibility with top paint, environmental pollution, complex processing, high energy consumption and other defects of the hot-dip zinc process, its development is limited. In view of the above deficiencies, new anti-corrosion coating materials and processes were investigated in this study. Zinc coatings and Al-Zn coatings were prepared on the C45 steel matrix by hot-spraying and cold-spraying processes. The macro appearance, micromorphology and phase composition analysis of the coatings were evaluated. The adhesion of the coating to the substrate after the salt-spray test was tested. The results showed that the hot dip zinc coating and hot spray zinc coating had obvious cracking after the salt-spray test. The surface structure of cold-sprayed Al-Zn coating was relatively dense after the salt-spray test. The critical load of the cold-sprayed Al-Zn coating after the salt-spray test was higher than that of the other two coatings. The corrosion resistance to salt spray of cold-sprayed Al-Zn coating was demonstrated to be better than the hot-dip zinc coating, and thus has great application prospects.