Environmental Sensitivity and Safety Assessment of Materials

To predict the corrosion failure of carbon steel oil and gas pipelines more accurately, a new corrosion failure prediction model for submarine oil and gas transport pipelines was constructed. A corrosion failure prediction management system was also developed based on the constructed model. To construct the model, corrosion experiments were carried out to analyze the influences of temperature, partial pressure of CO₂, pH value, and flow rate acting on the corrosion rate. Based on the analysis results and the corrosion experiment data, a new corrosion failure prediction model containing the time and flow rate for oil and gas pipelines was constructed. The model is based on the existing corrosion prediction model and has a determination coefficient, R², of 0.9573, which indicates good prediction accuracy. A machine learning prediction model was also used to predict, and the prediction results are compared with that of the proposed model, which further verifies the accuracy and feasibility of the proposed model. A corrosion failure prediction management system for carbon steel oil and gas pipelines was developed based on the constructed model, which makes corrosion failure prediction more convenient and faster and provides a reference for the accurate prediction and efficient control of oil and gas pipeline corrosion failure. Full article

To ensure that Al alloys are being served as the high-temperature structural components for applications in aerospace and transportation, it is necessary to investigate their high-temperature mechanical behavior and failure mechanism. In this paper, the mechanical behavior of the as-extruded Al-5Zn-2Mg-0.3Cu (in wt.%) alloy was studied and compared under different high-temperature tensile-testing conditions. It was found that the yield strength and the ultimate tensile strength of the alloy gradually decreased with the increase in temperature, but its elongation ratio showed a slightly increasing trend. Failure analysis demonstrated that there were a lot of ductile dimples on the fracture surfaces and that obvious necking occurred for the samples being tensile-tested at different temperatures. Surface observation revealed that the initiation of micro-cracks was mainly attributed to the self-cracking of the brittle phase particles. Moreover, when the testing temperature was between 450 °C and 550 °C, micro-cracks could also occur at the interface between phase particles and the Al matrix. Full article

Sodium lauryl ether sulphate (SLEnS) is an anionic surfactant that is widely used in many fields, such as cosmetics and detergents, among others. This study evaluated the influence of the number of ethylene oxide (EO) units, present in the head group of SLEnS, on its cytotoxicity to the A6 cell line of Xenopus laevis using MTT and resazurin assays. The A6 cell line was exposed for 48 h to six SLE_nS variants: SLE₀S, SLE₁S, SLE₄S, SLE₁₁S, SLE₃₀S, and SLE₅₀S (subscript values correspond to the number of EO units). Overall, the six variants impaired the A6 cells’ viability at low concentrations for the MTT assay, with the median lethal concentrations (LC_50,48h) ranging between 0.398 and 0.554 mg/L and for the resazurin assay between 0.557 and 0.969 mg/L. Further, the obtained results indicate SLE_nS variants with fewer EO units to be the most cytotoxic in the resazurin assay; although a similar cytotoxicity pattern was observed with the MTT assay, a significant association between the number of EO units and the values of LC₅₀ was not found. This result highlights the usefulness of in vitro assays with A6 cell lines as a first screening tool for assessing the structure–toxicity relationship of this type of surfactant, also providing a baseline for the development of environmentally friendlier chemical compounds while still maintaining their efficiency. Full article

X80 steel is extensively used in hydrogen environments and is susceptible to hydrogen embrittlement (HE). This paper studied the hydrogen-induced cracking (HIC) behavior in the coarse-grained heat-affected zone (CGHAZ) of X80 steel welds, through applying in situ hydrogen-charging tensile experiments, hydrogen permeation experiments, and various surface analysis techniques. It is shown that a few hydrogen atoms can significantly decrease a material’s elongation and reduction of area. When the heat input (HI) was 29.2 kJ/cm, the material had minor sensitivity to hydrogen embrittlement. The tensile fractures were ductile without hydrogen. However, the fracture surface exhibited brittle fracture with hydrogen. With increased HI, the HE fracture showed a transition of intergranular fracture→intergranular and transgranular mixed fracture→transgranular fracture. In the presence of hydrogen, the grain boundaries of elongated strips were prone to the formation of intergranular cracks under a tension load, and the hydrogen embrittlement resistance of the bulk lath bainite (LB) was weak. The hydrogen embrittlement susceptibility of pure granular bainite (GB) was lower. Fine LB and GB composite structures could remarkably inhibit intergranular cracks, giving the steel a superior resistance to hydrogen embrittlement. Full article

Much of the equipment that is used in the chemical and process industry and for handling or treating hazardous substances is subject to deterioration. To manage the risk of major accidents due to this deterioration, the current legislation requires periodic controls that must be carried out to verify the health conditions (ageing). To support the inspectors performing this task, a virtual sensor has been designed and developed. It is a system composed of hardware and software that uses mathematical models and augmented reality to assist in on-field inspections for monitoring and predicting equipment ageing. Currently, there are no AR devices to perform inspections aimed at verifying the integrity of equipment. The virtual sensor collects ageing-related information and returns the corrosion rate, the probability of the critical pit, the corrosion evolution through iso-contour corrosion maps, and the RUL; finally, it allows visualising the equipment condition through augmented reality, (e.g., by means of thickness maps and tables that overlay the equipment). The aim of this paper is to present the graphical interface of the software application, which has been improved to minimise errors due to human–machine interaction. A large diesel storage tank has been used to show how the virtual sensor works. Full article

Conjugated poly(3,4-ethylenedioxythiophene) (PEDOT) film was electrochemically synthesized on stainless steel (SS). Redox interactions between the PEDOT film and the SS substrate were examined in 3.5 wt.% NaCl aqueous solution with the aid of electrochemical and spectroscopic analyses. The results show that the PEDOT film exhibited a barrier effect and mediated the oxygen reduction reaction, thus hindering ion diffusion to the steel substrate. Localized electrochemical impedance spectroscopy (LEIS) of the scratched area on the polymer film shows that PEDOT healed the defect by coupling with redox reactions on the steel surface to prevent charge localization and concentration. The electroactivity of the polymer film declined when PEDOT was polarized at potentials >−0.7 V. Prolonged exposure of the PEDOT film to dissolved oxygen in NaCl solution resulted in the polymer’s over-oxidation (degradation), evidenced by the formation of a carbonyl group in the spectroscopic result. The degradation of PEDOT was attributed to chain scissoring due to hydroxide ion attacks on the polymer chain. Full article

Sb-doped SnO₂ (SnO₂-Sb) coatings show superiority in degrading toxic and refractory organic pollutants. SnO₂-Sb coatings can be prepared by oxidizing electrodeposited Sn-Sb coatings through an annealing process. The properties and structure of SnO₂-Sb coatings can be tailored by adjusting the preparation parameters. This study examines the effects of crucial preparation parameters on the performance of SnO₂-Sb coatings, with the aim of enhancing their properties.Determining the coatings’ cross-sectional and surface characteristics was accomplished using various characterization techniques. A thorough investigation of the prepared samples’ phase and element components was also carried out. Based on the findings, the surface roughness of the prepared Sn-Sb precoating changed with increasing current density, yet the primary surface features of the SnO₂-Sb coatings were hardly altered by the annealing process. Without lowering the coating thickness, the appropriate current density of 30 mA/cm² produced a rough and active coating surface. Our study’s proper annealing temperature of 600 °C transformed Sn-Sb precoating into SnO₂-Sb coating and achieved excellent coating quality.While changes in the Sb content affected the morphology of the prepared SnO₂-Sb coatings, the mixed oxide coatings’ cassiterite SnO₂ phase was unaffected. These results may provide insights into the optimized use of SnO₂-Sb coatings in various applications. Full article

Flood-controlled ancient dikes play a significant role in flood control and have received widespread attention as historical and cultural symbols. Flood-controlled ancient dikes often undergo disasters, and research on their repair is receiving increasing attention from experts and scholars. This article studies the control of seepage and bank slope instability in flood-controlled ancient dikes. Starting from the repair of ancient dike materials, three types of work are carried out: a test of soil’s mechanical properties, finite element numerical simulation, and repair technology research. The research results show that the soil of the ancient dike site has hardened after being contaminated with waste oil from catering. The strength index of the ancient dike soil decreases and shows brittleness when the water content is 15% and the oil content exceeds 6%. The strength index and permeability coefficient of oil-contaminated soil improved using modified lime mortar (MLM), which was achieved using the method of MLM to repair oil contaminated soil. When the MLM content was 10% and the oil content was 6%, the friction angle of the soil sample reached its maximum value. When the MLM content was the same, the higher the density of the soil sample, the greater the friction angle and cohesion and the smaller the permeability coefficient. Establishing a finite element numerical model, through comparative analysis, it was found that after MLM remediation of oil-contaminated soil, the extreme hydraulic gradient of the ancient dike decreased by 31.3%, and the extreme safety factor of the bank slope stability increased by 31.2%. MLM pressure grouting technology was used to improve the soil during the remediation of contaminated soil at the ancient dike site. Through on-site drilling inspection, the effective diffusion radius of MLM grouting was obtained, and the plane layout and grouting depth of MLM pressure grouting were determined. The on-site water injection permeability test showed that using MLM pressure grouting technology can effectively repair oil-contaminated soil in the ancient dike while reducing the permeability coefficient by 8–15%. Full article

In this study, the effect of electrochemical hydrogen charging on the corrosion behavior of an as-cast Mg–8%Li alloy was investigated. It was revealed that after being cathodically hydrogen charged in a 0.1 M NaCl solution at a constant current density of 50 mA/cm² for 3 h, a product film with an average thickness of 20 μm was formed in the α-Mg phase, whilst the average thickness of the product film being formed in the β-Li phase was 6 μm. When the charging time was prolonged to 18 h, the thicknesses of the product films being formed on the α-Mg and β-Li phases were increased to 75 and 20 μm, respectively. The results of the grazing incidence X-ray diffraction (GIXRD) testing showed that the product films of the differently charged samples mainly consisted of Mg(OH)₂, LiOH and Li₂CO₃. The formed product films on the two matrix phases were dense and could hinder the erosion of Cl⁻ in a solution, and hence improved the corrosion resistance of the alloy. After being hydrogen charged for 3 h, the charge-transfer resistance (R_ct) value of the alloy was increased from 527 to 1219 Ω·cm². However, when the hydrogen charging time was prolonged to 18 h, the R_ct was slightly reduced to 1039 Ω·cm² due to the cracking of the surface product films and the interfacial cracking of the film/substrate matrix. Full article

This investigation proposes the use of sol-enhanced electrodeposition to create a range of Co−Ni−TiO₂ films. The addition of TiO₂ sol controls the nucleation process and the properties of the composite films by generating TiO₂ nanoparticles in situ in the electrodeposition process. The transmission electron microscopy (TEM) and zeta potential analyses revealed a relatively homogenous distribution with particle size in the range below 100 nm for the TiO₂ nanoparticles produced. Microstructure, phase composition, hardness, friction, and corrosion resistance of Co−Ni−TiO₂ films were thoroughly investigated in relation to TiO₂ sol concentration. The results show that the addition of a limited content of TiO₂ sol upgraded Co−Ni films by producing a Co−Ni−TiO₂ film with a high dispersion of TiO₂ nanoparticles. On the other hand, too much TiO₂ sol could cause agglomeration and hinder the metal deposition process, resulting in surface pores and the deterioration of film performance. Full article

This study introduces a methodology for detecting the location of signal sources within a metal plate using machine learning. In particular, the Back Propagation (BP) neural network is used. This uses the time of arrival of the first wave packets in the signal captured by the sensor to locate their source. Specifically, we divide the aluminum plate into several areas, design eight receiving points for receiving the excitation signal, and determine the location of each sound source. In order to train and test the machine learning network, the aluminum plate model was established using the COMSOL numerical simulation platform and the propagation of five peak waves was simulated. Correspondingly, experimental verification was carried out and a scanning laser Doppler vibrometer (SLDV) was used to build an experimental platform to collect the corresponding wave field information to obtain a data set for machine learning. The results show that the trained BP neural network can classify the sound source region in both environments. Full article

The quantity of waste from end-of-life vehicles is increasing with an increase in the number of scrapped internal combustion engine vehicles owing to international trends such as carbon neutrality and particulate matter reduction. The recycling rate must be ≥95%; however, the average recycling rate remains at approximately 89%. Therefore, the improvement of the recycling of automobile shredder residues (ASR) is gaining attention. In this study, four types of products (interlocking, clay, and lightweight swelled ceramic (LSC) bricks, and asphalt paving aggregate (APA)) were manufactured using ASR melting slag (ASRMS). Environmental performance, quality standards, and technology were evaluated to assess the recyclability of the manufactured bricks. The interlocking brick substituted melting slag for sand and stone powder as an aggregate. As melting slag content increased, absorption decreased and bending strength increased. Clay brick was manufactured by replacing kaolin and feldspar with melting slag that substituted for 20%. The quality of clay bricks mixed with over 15% melting slag was not better than standard. Asphalt paving aggregate was used to investigate the optimum condition of slag content in mixed asphalt; the mixture ratio showed that 61% broken stone of 13 mm, 6% screenings, 10% melting slag, 15% sand and 8% filler was most effective. A lightweight swelled ceramic brick was manufactured by using melting slag, front glass, and so on. Specific gravity and compressive strength ranged from 0.38 to 0.51 and from 339.7 to 373.6 N/cm². ASRMS exhibited an environmental performance suitable for recycling and the manufactured bricks satisfied the quality standards. The recyclability of ASR was also assessed in terms of waste usage, conformance to quality standards, market size, and demand prediction. APA showed the best results followed by interlocking, clay, and LSC bricks. Full article

When constructing tunnels in mountainous areas, the drilling and blasting method is the most commonly used because of its economy. Ordinary reinforced concrete itself has defects such as poor crack resistance and brittleness. Therefore, when using the drilling and blasting method for ordinary reinforced concrete double-line tunnels, vibration phenomena will occur and cause cracks in the first-line tunnels, which will have adverse effects on the durability and safety of the tunnel. As a response, scholars have proposed the use of steel fiber-reinforced concrete as tunnel lining. In this paper, the LS-DYNA software is used to establish three models of plain concrete, ordinary concrete, and steel fiber-reinforced concrete, and numerical analysis is conducted with different amounts of explosives. The results show that the steel fiber-reinforced concrete tunnel lining has better performance than the other two concretes in tunnel construction. Full article

Investigating the failure mechanism of solder joints under different temperature conditions is significant to ensure the service life of a printed circuit board (PCB). In this research, the stress and strain distribution of a PCB solder joint was evaluated by high- and low-temperature thermal shock tests. The cross-section of the solder joint after thermal shock testing was measured using a 3D stereoscopic microscope and SEM equipped with EDS. The microstructure of the lead-free solder joint and the phase of the intermetallic compound (IMC) layer were studied by XRD. The working state of the PCB solder joint under thermal shock was simulated and analyzed by the finite element method. The results show that thermal shock has a great effect on the reliability of solder joints. The location of the actual crack is consistent with the maximum stress–strain concentration area of the simulated solder joint. The brittle Cu₆Sn₅ and Cu₃Sn phases at the interface accelerate the failure of solder joints. Limiting the growth of Cu₆Sn₅ and Cu₃Sn phases can improve the reliability of solder joints to a certain extent. Full article

The shock initiation randomness problem of energetic materials (SIREM) is an important problem in the research field of energetic material safety. With the purposes of solving SIREM on a macroscopic scale and obtaining the statistics, such as the initiation probabilities of energetic materials and the statistical characteristics of the detonation pressure, this paper considers the effect of the randomness of the parameters of the Lee–Tarver equation of reaction rate and the JWL equation of state of energetic materials and the randomness of load intensity parameters—such as fragment shock velocity—on the randomness of the shock initiations of energetic materials. It then decomposes SIREM into an initiation probability problem (IP) and a detonation pressure randomness problem (DPR). Further, with the Back Propagation Neural Networks optimized by the Genetic Algorithm (GABPNN) as the surrogate models of the numerical models of two-phase reactive flow, this paper proposes the approach of solving IP and DPR in turn, adopting Monte Carlo Simulations, which use the calculations of GABPNNs as repeated sampling tests (GABP-MCSs). Finally, by taking the shock initiation randomness problem of Composition B as an applied example, this paper adopts GABP-MCS under the randomness conditions that the means of fragment shock velocities are 1050 m/s and 1000 m/s and that the coefficients of variation (CVs) of BRVs are 0.005, 0.01, 0.015, and 0.02 in order to obtain the initiation probabilities of Composition B and the statistical characteristics, such as the means and CVs of the detonation pressure. It further observes the variation tendencies that these statistics show under various randomness conditions, so as to prove the effectiveness of GABP-MCS in solving SIREM. Therefore, this paper investigates SIREM on a macroscopic scale and proposes a universal technique for solving SIREM by GABP-MCS, in the hope of shedding some light on the SIREM study. Full article

In this study, we investigated the microstructure, mechanical properties, and thermal performance of Sn-xBi-1Ag (x = 35, 37, 45, and 47 wt.%) solders, with a particular focus on the effect of adding trace Si atoms. The impact of different Ag concentrations on the properties of Sn-xBi-Ag-0.5Si solders was also studied. The results indicated that as the amount of Bi added to Sn-xBi-1Ag solder alloys increased, the tensile strength, microhardness, melting temperature, and melting range decreased somewhat, but the wettability improved. The Cu₆Sn₅ layer between the soldering alloy and the Cu substrate became thinner upon increasing the Bi content. Adding microcrystalline Si atoms to the Sn-Bi-1Ag alloy improved the tensile strength and microhardness, but the melting point and melting range were not significantly changed. The wettability was optimized, and the diffusion layer formed with the Cu matrix was significantly thinner. By increasing the Ag content in the Sn-Bi-(1,3)Ag-0.5Si alloy, the tensile strength of the alloy was continuously strengthened, while the hardness decreased slightly and the melting point and melting range increased slightly. The wettability was greatly improved, and the Cu₆Sn₅ layer became thinner. Full article

In this study, an electrochemical hydrogen permeation experiment was used to determine the diffusion parameters, and a hydrogen microprint test was used to visualize the distribution of hydrogen in X65 pipeline steel with different levels of cold deformation. The hydrogen permeation curves show that both hydrogen permeation current density and effective hydrogen diffusion coefficient decrease with increasing cold deformation. The density of reversible and irreversible hydrogen traps is calculated from the permeation parameters, and it is found that the amount of both traps increases with increasing deformation, especially a significant increase in reversible hydrogen traps, which is in agreement with the results measured by thermal desorption spectroscopy. Hydrogen microprint test results indicate that the degree of hydrogen aggregation on the specimen surface increases with increasing cold deformation, especially at phase and grain boundaries. In addition, the dislocation configuration after cold deformation was further investigated by transmission electron microscopy. Full article

Urea can solve the problem of concrete cracking due to temperature stress. However, its effect is affected by temperature. The influencing mechanism of temperature on urea-doped cement pastes is still unclear. This paper explores the effect of different temperatures on the hydration kinetics of urea-doped cement pastes. The isothermal calorimeter (TAM Air) was used to test hydration at three constant temperatures (20 °C, 40 °C, and 60 °C). The effects of the urea admixture and temperature on the hydration process and hydration kinetics parameters were investigated. The hydration mechanism was analyzed, and the changes in macroscopic mechanical compressive strength and porosity were tested. The results show that, as the urea content (UC) increases, the rate of hydration gradually decreases, and the increase in temperature promotes the inhibitory effect of urea. At 60 °C, UC of 8% can be reduced by 23.5% compared with the pure cement (PC) group’s hydration rate. As the temperature increases from 20 °C to 60 °C, the Krstulovic–Dabic model changes from the NG-I-D process to the NG-D process. The effect of urea on the compressive strength of the cement is mainly shown in the early stage, and its effect on later strength is not obvious. In addition, urea will increase its early porosity. The porosity will gradually decrease in the later stage. The results of the study clarify the effect of temperature on urea-doped cement pastes. The optimal content of urea in cement is about 8%, which will provide theoretical guidance for solving the cracking problem of large-volume concrete due to temperature stress. Full article

Amorphous materials have shown great potential in removing azo dyes in wastewaters. In this study, the performance of FeSiB amorphous materials, including FeSiB amorphous ribbons (FeSiB^AR), and FeSiB amorphous powders prepared by argon gas atomization (FeSiB^AP) and ball-milling (FeSiB^BP), in removing toxic Pb(II) from aqueous solution was compared with the widely used zero valent iron (ZVI) powders (Fe^CP). The results showed that the removal efficiency of all the amorphous materials in removing Pb(II) from aqueous solution are much better than Fe^CP. Pb(II) was removed from aqueous solution by amorphous materials through the combined effect of absorption, (co)precipitation and reduction. Furthermore, FeSiB^AP and FeSiB^BP have relatively higher removal efficiencies than FeSiB^AR due to a high specific surface area. Although the FeSiB^BP has the highest removal efficiency up to the first 20 min, the removal process then nearly stopped due to aggregation. Full article

This paper presents research upon the impact of ecological measures on the water content of new and used oil. Water and microorganisms are major factors of contamination for engine oils and fuels, and they lead to a significant reduction in the lifetime and performance of engines. The microorganisms occur naturally in the environment, from which they enter into the oil and fuel. Despite various preventive measures, it is not possible to completely remove water from petrochemical products. That is why the protection against and prevention of the various types of contamination of petroleum products, especially microbiological contamination, is very important. Biocides are one example of the agents used for the prevention of contamination; biocides belong to a group of pesticides that are used to eliminate microbial contamination. Due to the fact that currently available methods are ineffective and often have a detrimental effect on the natural environment, research is underway to discover modern and ecological measures to combat the phenomenon of the microbiological contamination of petroleum products. This paper shows the effects of environmentally friendly additives on the water content in lubricating oil, i.e., whether these additives cause the release of water bound in the oil, and whether their composition increases the water content of the oil. Samples of new and used oil were utilized for the tests. Effective microorganisms (EM), in both liquid form and within ceramic tubes, were added to the new and used oil samples. In addition, silver solution and silver compounds were added in the same amounts as the liquid effective microorganisms. In order to confirm and compare the obtained test results, the dynamic viscosity, flash point, acid number, base number, and water content were measured, and these are presented in this study. These measurements were followed by the analysis of the influence of the additives on the water content. It was found that the adding of effective microorganisms to fresh oil in liquid form caused a significant increase in the water content of the oil; in the case of a smaller amount (2.5 mL), the water content more than doubled, and in the case of a larger amount, the water content exceeded the measuring range of the device. Next, an evaluation of the impact of these environmental measures on the water content was carried out. It was found that the adding of liquid effective microorganisms to new oil caused a significant increase in the water content of the oil; the water content more than doubled for the addition of 2.5 mL, while for a larger addition (5 mL), the water content exceeded the measuring range of the device. The same was true for the addition of silver compounds, regardless of their type and amount. The best results were obtained with ceramic effective microorganisms, but the results for silver cannot be presented due to the over-titration of the device (the amount of water exceeded the measuring range). For used oil, the liquid effective microorganism was found to give the best result. Full article

In order to study the bond-slip constitutive model between prestressed tendons and concrete, the pull-out tests of single-strand and multi-strands specimens are carried out. The effect of the number of prestressed tendons on the failure mode, slip characteristics and concrete strain of the pull-out specimens are analyzed, and the constitutive models of bond-slip between for single- strand and multi-strand tendons are also proposed. The results show that the bond mechanism between steel strand and concrete is basically similar to that of deformed steel bar, but the slip process of steel strand along the axis direction is accompanied by rotation phenomenon because it is twisted. Moreover, compared with the single-strand prestressed tendon, the average ultimate bond stress of each tendon of the three-strand prestressed tendons decreases by 13.2%. In addition, the calculated result of the pull-out limit load for the single-strand prestressed tendon is only 2% higher than the experimental value, while the corresponding value of three-strand prestressed tendon is only 3.74% lower than the experimental value. This means that the proposed bond-slip models for single- strand and multi-strand tendons have high reliability. Full article

Calcium phosphate chemical conversion coatings with the additions of sodium lauryl sulfate (SLS) and dodecanesulfonic acid sodium (DSS), respectively, were prepared on the surface of the Mg-8Li alloy. The surface and cross-sectional corrosion morphologies, compositions, and corrosion behavior of the coated surfaces in 3.5 wt.% NaCl solution were respectively investigated by using a scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electrochemical workstation, hydrogen evolution apparatus, and optical microscope (OM). The results demonstrated that Ca-P coatings had a petal-like structure being composed of leaf-like particles. After being respectively performed for 30 min in conversion solutions containing SLS and DSS, the corresponding average film thicknesses of surface coatings were 27 μm and 7 μm. In addition, the corrosion current densities of coated surfaces by using the conversion solutions containing SLS and DSS were 1.438 × 10⁻⁵ A·cm⁻² and 4.719 × 10⁻⁵ A·cm⁻², respectively. The effect of surfactants on phosphate chemical conversion coating was discussed in detail. Full article

In view of the increasingly serious problem of marine ecological environmental pollution, the traditional marine environmental corrosive pollution monitoring technology has poor monitoring accuracy and poor monitoring timeliness, and the improvement of the marine environmental corrosive pollution monitoring technology under the cloud computing platform is proposed. The research significance and corrosion influence factors of steel corrosion in the marine environment are described, and the research progress of corrosion mechanism in five different zones of the marine environment is reviewed. Cloud computing parallelizes the processing of corrosive pollution data in the marine environment through virtualization and distributed technology, which greatly improves the efficiency of the algorithm. This paper studies the existing cloud computing platform and ocean monitoring system architecture, uses the distributed architecture to design a cloud computing-oriented ocean monitoring system and meets the design requirements in data collection and data processing. The experimental results show that the precision of marine environmental corrosion pollution monitoring technology proposed in this paper is 96% on average, and the completion rate of monitoring images is 82% on average, which can effectively realize marine environmental corrosion pollution monitoring. Full article

Herein, composite extrusion deformation and heat treatment process at various temperatures were studied on a new type of Al-Zn-Mg-Cu alloy billet. The influence of pre-deformation and the final forming of extrusion and heat treatment of annular channel corner extrusion on the microstructure evolution and mechanical properties were explored. The results show that the extrusion process could further refine the structure and break the coarse θ phase. The grains can be refined again after the deformed sample was treated by solution-aging treatment. At the same time, a fine, dispersed second phase is precipitated around the fine recrystallized grains. This is the main reason for the increase in alloy elongation and tensile strength. The best heat treatment process parameters for the formed cup-shaped structure are 480 °C × 1 h solid solution and 120 °C × 24 h aging. The strengthening of the alloy mainly includes three mechanisms: fine grain strengthening, precipitation strengthening, and dispersion strengthening. Full article

As reinforcement material, geocells are widely used in various types of embankment reinforcement. A lot of practical experience shows that geocell reinforced embankment has good reinforcement effect, but the theoretical research lags behind the engineering practice, and the reinforcement mechanism under cyclic loading under various reinforcement conditions needs to be further studied. In this paper, the reasonable reinforcement condition of geocell reinforced embankment under static and cyclic loading is proposed by using a physical model and numerical simulation comparative analysis method. The research findings include: under cyclic loading, the inhibition effect of the number of reinforced layers on the vertical cumulative settlement is better than that under static loading, but the effect of two-layer reinforcement and three-layer reinforcement is relatively close, and both can reduce the vertical settlement by more than 40%. The inhibition effect of the increase of geocell height on the horizontal deformation of slope surface is better than that of the decrease of welding spacing under cyclic loading, and the reinforcement effect of the middle and upper part of embankment is better. Increasing the height of geocell and reducing the welding spacing can improve the limit bearing capacity of embankment, and the former is better. The optimal reinforcement condition of sandy soil embankment under cyclic loading obtained from the comparative analysis is case 3, that is, the reinforced layers is 2, the geocell height is 10 mm, and the welding distance is 50 mm. Full article