The accurate identification of vehicle weight and speed based on road embedded piezoelectric systems (REPS) is a hot topic in the field of dynamic weighing research. An analytical method incorporating loss impedance is proposed in this paper to enable accurate vehicle identification using a REPS. Complementing this framework, a multi-field coupled finite element model (FEM) of the traffic load-road-REPS is developed based on a dual-row sensor array configuration, fully accounting for the actual electromechanical structure of the REPS. A systematic investigation is conducted on how key factors-including vehicle weight, speed, tire contact area, and lateral and longitudinal loading deviations-affect the dynamic and piezoelectric response. Building on these insights, this paper introduces a voltage deviation coefficient and a vehicle load compensation coefficient to correct signal distortions caused by variable contact geometries and positional offsets. By incorporating these coefficients into a bias-corrected identification framework, the proposed method enables simultaneous estimation of vehicle speed and wheel load, reducing the wheel-load identification error to 5.54%, approximately 50% lower than that obtained using the uncompensated axle-load prediction. The research results provide a theoretical foundation for the further development and application of REPS-based weigh-in-motion system.

The pressure-resistant shell plays a critical role in determining the submerged depth of underwater vehicles. Traditional pressure-resistant shell designs are confronted with challenges such as high sensitivity to defects, poor space utilization, and limited load-carrying capacity. The proposed ring-stiffened sandwich cylindrical shell redistributes the load between inner and outer shell plates, significantly reducing the plate thickness and enhancing stealth potential. New strength and stability criteria are provided, and a parametric geometric model is developed. Additionally, a rapid optimization design method based on the MIGA surrogate model and the radial basis function neural network (RBFNN) surrogate model is utilized to improve effective design efficiency. Numerical analyses of underwater vibration and acoustic radiation demonstrate the superior acoustic stealth performance of the proposed structure, thereby contributing to addressing key challenges in the development of deep-diving underwater vehicles.

Traditional vacuum preloading, electroosmotic techniques face challenges such as poor removal efficiency, reinforcement and high energy consumption when treating contaminated sludge with high water content. This study investigates the reinforcement and remediation of nickel (Ni)-contaminated sludge with high water content using an approach combining grouting, vacuum preloading, and electroosmosis (GVE). Through laboratory model tests, the effects of grouting agents, vacuum preloading, and voltage loading modes on Ni removal efficiency, soil reinforcement, and energy consumption were evaluated. The results demonstrate that the grouting of sodium alginate can chelate Ni2+ in the soil, facilitating the removal of heavy metal ions during the electroosmosis process. The GVE combined with vacuum preloading significantly enhances Ni removal rates, achieving up to 94.52 % compared to 65.11 % with electroosmosis alone. Additionally, GVE reduced soil water content to 30.34 % and increased shear strength to 98 kPa, indicating improved soil reinforcement. The step loading further reduced energy consumption by over 35 % compared to constant voltage loading while enhancing both soil remediation and reinforcement. This study concludes that GVE, particularly with step loading and intermittent loading, is an effective and energy-efficient method for remediating and reinforcing heavy metal contaminated sludge.

Potassium (K) is known to enhance the catalytic performance of Fe-based catalysts in the reverse water-gas shift (rWGS) reaction, which is highly relevant during Fischer-Tropsch (FT) synthesis of CO2-H2 mixtures. To elucidate the mechanistic role of K promoter, we employed density functional theory (DFT) calculations in conjunction with microkinetic modelling for two representative surface terminations of H & auml;gg carbide (chi-Fe5C2), i.e., (010) and (510). K2O results in stronger adsorption of CO2 and H2 on H & auml;gg carbide and promotes C-O bond dissociation of adsorbed CO2 by increasing the electron density on Fe atoms close to the promoter oxide. The increased electron density of the surface Fe atoms results in an increased electron-electron repulsion with bonding orbitals of adsorbed CO2. Microkinetics simulations predict that K2O increases the CO2 conversion during CO2-FT synthesis. K2O also enhances CO adsorption and dissociation, facilitating the formation of methane, used here as a proxy for hydrocarbons formation during CO2-FT synthesis. CO dissociation and O removal via H2O compete as the rate-controlling steps in CO2-FT. Published by Elsevier B.V. All rights reserved.

Potassium (K) is widely used as a promoter in industrial Fe-based Fischer-Tropsch (FT) catalysts to enhance CO conversion and increase the chain-growth probability while decreasing CH4 selectivity. We deployed density functional theory calculations and microkinetics simulations to elucidate the mechanistic role of K promotion on chi-Fe5C2 (Hagg carbide). The preferred state of K under reaction conditions, K2O, on the reactive (010) surface strengthens the adsorption of CO, H, C, and CH. This results in faster C-O bond dissociation and slower hydrogenation reactions. The main FT reaction mechanism involves HCO dissociation, O removal as H2O, CH+CR (R = alkyl group) coupling reactions, and termination by alpha-CH hydrogenation to olefins. Microkinetics were determined to study the impact of K on the FT reaction catalyzed by the chi-Fe5C2(010) surface. Irrespective of the presence of K, the FT reaction operates at the interface of chain growth-limiting and oxygen removal-limiting regimes, with CCH2 hydrogenation and OH disproportionation controlling the overall CO conversion rate. On the unpromoted surface, CO hydrogenation and CHO dissociation control the chain-growth process and slightly inhibit the overall CO conversion rate. Simulations of the K-promoted surface demonstrate that K promotion removes the kinetic limitation of CHO dissociation in the chain-growth process. Overall, K2O increases the chaingrowth probability while decreasing the CH4 selectivity because the impact of the promoter is stronger for CH4 formation than the hydrogenation reactions of olefinic surface precursors. The main effect of K2O on the intrinsic FT chemistry is electronic, involving electron transfer to Fe surface atoms. The main kinetic consequences are a lower overall barrier of CHO dissociation and higher barriers for the hydrogenation of carbon-containing surface intermediates.

The removal of carbon deposits from carburized Fe-based Fischer-Tropsch catalysts is a critical aspect of their performance. In this study, a method is presented to remove carbon deposits from freshly prepared chi-Fe5C2. The method involves successive passivation and reduction steps, which do not affect the bulk structure of the chi-Fe5C2 catalyst. The passivation step transforms the carbonaceous deposits from a graphitic structure to a disordered oxygen-functionalized structure, facilitating its removal by a reduction step in hydrogen. This results in a higher initial activity of the catalyst and substantially shortens the induction period observed without such pretreatment. The findings underscore the possibility of improving catalytic performance of Fe-carbides by changing the structure and reactivity of carbonaceous deposits.

The dissociation of CO is a critical step in producing long-chain hydrocarbons in the Fischer-Tropsch (FT) synthesis reaction. Although potassium (K) is known to enhance CO conversion and the selectivity to olefins of Fe-carbide FT catalysts, its precise mechanistic role remains unclear. In this work, we used density functional theory to show that K2O facilitates C-O bond dissociation in CO, HCO, and COH by increasing the electron density of the Fe surface atoms of H & auml;gg carbide (chi-Fe5C2) that bind these surface intermediates. This leads to a higher electron density in anti-bonding orbitals and enhanced electron-electron repulsion between the bonding orbitals of the CO, COH, and HCO intermediates and the Fe atoms. Effective promotion of C-O bond dissociation requires K to be adjacent to the active site on the chi-Fe5C2 surface.

This paper explores the application of simply supported beam (SSB) piezoelectric transducer for capturing mechanical energy from road vibrations and converting it into electrical energy. A theoretical model incorporating loss impedance and material damping is established to predict the transducer’s piezoelectric performance, with its accuracy subsequently verified through test results. The research examines the relationship between output performance and various influencing factors, including piezoelectric material characteristics, load amplitude, frequency, and the number of transducers. The findings indicate that the SSB piezoelectric strain constant only affects the open-circuit voltage without influencing the piezoelectric impedance. Increasing damping and elasticity reduce the conversion efficiency of SSB transducer, whereas output power exhibits a positive correlation with both load amplitude and frequency. The number of transducers in parallel connection plays a crucial role in piezoelectric performance. An optimal SSB transducer configuration is suggested considering variations in load magnitude and frequency. These findings provide valuable insights for the design and optimization of piezoelectric energy harvesters in road vibration applications.

Conventional aerobic oxidation of biomass 5-hydroxymethylfurfural (HMF) encounters challenges due to the harsh conditions stemming from low solubility and high activation energy of O-2, which hinder the efficient production of 2,5-furandicarboxylic acid (FDCA). Here, we propose a tandem catalytic system that lowers the activation energy for O-2 to enable efficient and selective HMF oxidation to produce FDCA or 5-formyl-2-furoic acid (FFCA) under mild conditions. To overcome the high activation energy of O-2 in the thermocatalytic processes, an electrochemical O-2 activation process was employed to efficiently produce H2O2 as an oxidant to valorize HMF into either FDCA or FFCA. This tandem catalytic system achieved a cumulative FDCA yield of 2.21 mol g(Ru)(-1), full HMF conversion (100%), and complete product selectivity (100%), with an average productivity of 13.19 mmol g(Ru)(-1) h(-1) over an extended 170 h operation period. The FDCA productivity in this work exceeds that in most aerobic oxidations under mild conditions. Further investigation into the detailed reaction process demonstrated that OH from H2O dissociation directly interacted with the aldehyde group in HMF to form a carboxylic acid group, while H2O2 serves as an oxidant to extract electrons from HMF or reaction intermediates. Furthermore, the efficient oxidation of structurally diverse substrates from EtOH to glycerol demonstrates the broad applicability of this tandem catalytic system.

As a rapid construction method, the technology of prefabricated assembled bridge piers has become an important direction in the development of modern bridge engineering. To promote the application of prefabricated segmental assembled bridge piers in high seismic intensity areas, a hybrid connection method for prefabricated segmental assembly is proposed. This connection method involves using a socket connection between the bottom segment of the pier shaft and the cap, employing ultra-high performance concrete (UHPC) as the grouting material, and connecting each segment of the pier shaft, cap, and cap beam into an integrated unit using prestressed tendons. To investigate the feasibility of this connection method, prefabricated segmental assembled hybrid connected double-column bridge pier specimen SQ-1 and cast-in-place double-column bridge pier specimen SQ-2 were designed and fabricated. Quasistatic tests were conducted to compare the damage phenomena, hysteresis and skeleton curves, residual displacement, and energy dissipation (ED) capacity of the two specimens. The research results indicate that the concrete damage degree of the prefabricated segmental assembled hybrid connected double-column bridge piers is lower than that of the cast-in-place double-column bridge piers. The hybrid connection design effectively mitigates the propagation of concrete damage. Although the ED capacity of the prefabricated segmental assembled hybrid connected double-column bridge piers is not as good as that of the cast-in-place double-column bridge piers, they perform better in terms of deformation capacity and residual displacement. They also exhibit good self-centering characteristics, which is beneficial for postearthquake repair and maintenance.

The non-uniform dense soil column that forms around plastic drainage plates when using vacuum preloading to treat flowing mud exhibits varying clogging along the extension direction, which severely lowers both the consolidation effectiveness and rate of consolidation. A transient clogging model is established based on indoor tests conducted under varying vacuum pressure for analyzing the evolution and impact of soil column along the plastic drainage plate direction. The study reveals that the vacuum pressure attenuation alters soil water content, density, and permeability, resulting in the formation of a “carrot-shaped” clogging zone, which adversely affects the drainage rate and consolidation uniformity. Building on the transient clogging model, a vacuum consolidation analysis method is proposed taking into accounting for the nonlinear vacuum transfer and soil characteristics. The validity of the proposed method is confirmed through case studies, accompanied by a detailed parameter analysis and discussion.

In this paper, experimental data during the compression and stretching of ultra-thin-walled deployable composite lens rods are compared with the finite element analysis data to study the flattening and stretching. The advantages and disadvantages of the two compression methods in the process of compressing the lens rod are examined. The compression process of the lens rod can be considered a small strain process with nonlinear deformation. First, the composite lens rod model created by ABAQUS was established for a finite element simulation analysis of the compression and tension. Second, compression and tensile experiments were performed on the pod samples. Then, by comparing the measurement results and the corresponding finite element simulation results, we verified the accuracy of the finite element simulation method and experiment. In the compression flattening mode and the tensile flat mode, the maximum error between the simulated and experimental values is 8.3% and 8.7%. Finally, by comparing the maximum tension, displacement, and strain results of the two compression methods, the compression squash is smaller and more uniformly distributed than the tensile squash stress, and the squash method should be preferred in the design of the mechanism.

The development of high-performance catalysts for dry reforming of methane (DRM) remains a huge challenge. Herein, we developed a series of acidized attapulgite (ATP) supported NiCo bimetallic catalysts (NiCo/ATP-x) and explored the impact of acidification temperature (AT) of ATP on the fine structure and DRM performance of as-prepared catalysts. It was found that AT of ATP significantly affected the ATP microstructure and further optimized the spatial electronic states of metallic sites and the distributions of acid sites and surface oxygen species. NiCo/ATP-190 (ATP was acidized at 190 degrees C) with the unique active silicon stabilized Ni-Co alloy as intrinsic active center exhibited superior conversions of CH4 (93.0%) and CO2 (82.9%) at 700 degrees C and 60,000 mL center dot gcat-1 center dot h-1 of gas hourly space velocity (GHSV). The performance of the catalyst was close to the state-of-the-art in this area of research. A combination of kinetic analysis and in-situ DRIFTS highlighted that the obvious reduction of methane activation energy barrier was attributed to the multi-site synergistic effect of NiCo/ATP-190, which could accelerate the crack of more CH4 molecules into CHx* and H* and then further produce syngas via CHxO* intermediates. This work opens a simple method for synthesizing highly efficient nickel-based attapulgite catalysts in DRM reaction.

Laboratory tests and theoretical analyses were conducted to investigate the membrane-free horizontal-vacuum (MFHV) method for inducing seepage consolidation in dredged marine fills. First, six well-designed tests with dredged marine slurry were conducted to simulate the consolidation behaviour with a prefabricated horizontal drain (PHD). The dewatering features under MFHV conditions were studied with respect to the drainage rate, settlement, water content, and permeability. The dewatering rate saltation (DRS) problem was systematically investigated by observing the changes in the supernatant water. The results indicated that the DRS problem existed in the case of the thin slurry layer rather than the thick slurry layer. Furthermore, a modified consolidation model was proposed considering the vacuum boundary and critical gradient. An explicit solution was provided to calculate the average consolidation degree and settlement. The settlement and DRS points obtained from the model tests and analytical solutions were compared. The results showed that the proposed analytical method could reasonably predict the consolidation behaviour of the MFHV method. In addition, a parameter study was conducted to investigate the influence of the critical gradient, void ratio, and compression index on seepage consolidation. Finally, an equation to design the optimum drain space for the MFHV-treated slurry was presented for direct engineering practice.

Composite foundations improved by impermeable columns and vertical drains are widely applied in various actual projects. However, few existing studies have reported nonlinear consolidation solutions for such composite foundations. In this study, a nonlinear consolidation model is developed with a time-dependent permeability coefficient for vertical drains. Then, the equation governing the consolidation of the composite foundation is derived, and the corresponding analytical solution is obtained. An iterative approach is adopted to minimize the errors generated in the simplified solution process. Through extensive calculations, the effect of time-dependent well resistance of vertical drains on the consolidation of such composite foundations is analyzed. The results show that ignoring changes in well resistance over time leads to an overestimation of the stress concentration effect of impermeable columns, consolidation of the composite foundation, and settlement rates. Finally, the proposed analytical solution is applied to the settlement calculations for a section of the Huai-Yan Highway and a section of the Lin-Lian Highway. Compared with the consolidation model with constant well resistance, the one with variable well resistance provides results that are more consistent with the measured data.

Clogging near the prefabricated vertical drain filter during vacuum preloading reduces the efficiency of ground treatment, and existing research has yet to agree on the cause. This study conducted a small model test to comprehensively examine the soil's water content and particle size distribution at different distances from the filter and tailwater for different preloading durations. The results showed that the particle size distribution of the soil at different selected points exhibited a slightly irregular difference. This indicates that no measurable migration of particles occurs, which was further confirmed by the particle size distribution of the soil after the one-dimensional consolidation test. The application of vacuum pressure did not significantly change the soil particle composition and, thus, its compressibility and permeability properties. The particle size distribution of tailwater revealed that a small number of fine particles with a mean size of 3–4 μm rapidly discharged with tailwater during the initial stage of vacuum preloading, which was much less than the mean size of the slurry and pore size of the filter. The decrease in water content and permeability indicates non-uniform consolidation, and the increase in the permeability coefficient ratio suggests the formation and development of the clogging zone.

As an emerging ground treatment technique, the air-boosted vacuum preloading method accelerates the consolidation process of soils with vertical drains and enhances the bearing capacity and stability of grounds. This improvement is achieved by augmenting the horizontal pressure differential between the drainage body and the surrounding soils. In the realm of existing theories, consolidation models are primarily established under the assumption of linear characteristics of soils. Nonetheless, for marine sedimentary soft soils characterized by high compressibility, the application of nonlinear consolidation theory becomes more appropriate. The well resistance effect of the drainage body over time is also considered in this study, and a comprehensive consolidation model tailored to soft soils with air-booster pipes and vertical drains is proposed. Subsequently, the analytical and numerical solutions for this consolidation model are derived, respectively. Comparisons are made with existing conventional linear consolidation models to substantiate the validity of the proposed consolidation model. This investigation delves into the influence of nonlinear compressibility and permeability of soils, variable well resistance, and drain spacing ratio, on consolidation behaviors. Particular emphasis is placed on the determination of the startup time for the air-boosted system. Finally, the proposed consolidation model is applied to the actual field prediction, affirming the accuracy and applicability of the developed consolidation model in practical soft soil treatments.

For chlorinated volatile organic compounds (CVOCs), it is critical to design and fabricate applicable noble metal catalysts to exhibit superior catalytic performance in catalytic oxidation under both dry air and 5.0 vol% H2O conditions. In pursuit of this goal, a facile strategy was developed to prepare a series of Pt-supported catalysts for the elimination of o-dichlorobenzene (o-DCB). Among these catalysts, Pt/CeAlZrOx possessed excellent activity (T-90 = 285 degrees C) and Pt/LaAlOx showed outstanding selectivity within/without 5.0 vol% H2O, attributed to the strong interaction of multi-components, abundance of adsorbed oxygen, prominent redox properties, and suitable acidity. According to the analysis results of density functional theory (DFT), the introduction of Pt can significantly improve the adsorption and activation of o-DCB molecules on the catalysts. Specifically, the action of Marse-van Krevelen (MvK) combining with Langmuir-Hinshelwood (L-H) mechanism was proposed. In general, this work provides promising candidates and valuable insights into the comprehensive improvement of o-DCB catalytic degradation for industrial application.

With the developments of the geotextiles industry, some electro-kinetic geosynthetics are used for the indoor tests of treating soils with electro-osmosis. Electro-osmotic treatment of soft soils has promising applications as synthetic electrodes are environmentally benign and have good hydraulic conductivity. However, the consolidation theory for soils treated by electro-osmosis combined with vacuum and surcharge preloading in which electrodes are installed in a hexagonal array has been rarely reported in the existing literature. Therefore, a consolidation model for such technologies is established in this study and the corresponding analytical solution is obtained. Then, the correctness of the proposed model is verified by comparing the results calculated by it with those calculated by the existing solutions and measured data. Finally, extensive calculations are performed to investigate the consolidation behaviors of soils under such condition, and the results show that the DC power supply is suggested to be cut off in the late stage of consolidation to reduce the cost; the energy consumption per unit volume of water discharged increases as the effective voltage increases; high benefits can be obtained by using the electro-osmosis for the treatment of soils when the thickness of soils is thin or the influential zone of each cathode is large.