This study investigated the durability of CFRP-to-steel bonded joints. First, durability tests were conducted on adhesive, CFRP sheets, and CFRP-to-steel double-lap joints in a neutral salt spray environment. Three types of influencing factors were considered in the joints, including steel surface treatment methods, number of CFRP layers, and types of CFRP sheets. The salt spray exposure durations were set at 500 h, 1000 h, 1500 h, and 2000 h. Subsequently, tensile tests were conducted on adhesive, CFRP sheets, and CFRP-to-steel joints. The effects of neutral salt spray on appearance, failure modes, and mechanical properties of adhesive and CFRP sheets were discussed. The influence of the steel plate surface treatment methods, the number of CFRP layers, and the types of CFRP sheets on shear strength, stiffness, and fracture energy of CFRP-to-steel joints, as well as their degradation mechanisms, were analyzed. Finally, aging duration-dependent equations were proposed by regression analysis to calculate the normalized mechanical performance of the adhesive, CFRP sheets, and CFRP-to-steel joints. The results indicate that the degradation of the adhesive's mechanical properties was much greater than that of the CFRP sheets over the same aging duration. The deterioration in the bonding performance of CFRP-to-steel joints was related to the degradation in the mechanical properties of adhesive-steel interface and adhesive. The surface treatment of the steel plate was crucial to the mechanical performance and durability of the joints. A rough steel plate surface, dense CFRP sheets, and multiple layers of CFRP could enhance the durability of CFRP-to-steel joints.

Fatigue strength of tubular structures made of cast steel nodes is generally governed by the fatigue strength of girth butt-weld between stubs in the cast steel node and hot rolled tubes. Previous experiments found that fatigue cracks initiated at the weld root of the girth butt-weld and propagated in the weld metal or heat affected zone of the weld. The present paper investigated the fatigue strength of the weld root crack of the girth butt-welds by using linear elastic fracture mechanics (LEFM) method. Different initial crack sizes, initial crack shapes and materials properties relating to crack propagation were studied based on literature review. Comparisons between the predicted results and Puthli's experimental results indicated that the LFEM model was valid. Size effect including thickness effect and eccentricity effect of unequal thickness was discussed based on this LFEM model. The fatigue strength of the girth butt-weld decreases as the plate thickness increases. But the increase of the eccentricity of the thickness may not always reduce the fatigue strength of the girth butt-weld.

The wave impeding board (WIB) is frequently integrated beneath dynamic machinery, tracks, and subgrades to counteract vibrations emanating from artificial sources. However, conventional WIBs have exhibited a limited isolation frequency band due to their dependence on the soil cut-off frequency of soil. Furthermore, the vibration sources typically encompass intricate frequency components spanning low, medium, and high frequencies. To overcome the technical limitations of WIBs relying on the cut-off frequency of soil, a new periodic structural wave impeding board (PSWIB) is proposed based on the principles of phononic crystals. Theoretical and numerical analyses demonstrate that PSWIB exhibits bandgap characteristics, with the attenuation range achieved by finite periodic structures aligning with the bandgap of an infinite PSWIB. Maximum amplitude reductions of 47 dB and 65 dB are achieved within the vibration attenuation range. Compared to traditional WIB, PSWIB surpasses the constraints imposed by the cut-off frequency of soil and allow for the design of constituent parameters based on the characteristics of the vibration source, enabling effective isolation of the target frequency vibrations.

Metal corrosion not only causes huge economic losses, but sometimes even endangers personal safety. Therefore, the requirements for the corrosion resistance of metals are becoming a significant problem. The use of inhibitor is still one of the most common and effective methods to prevent metal corrosion. An environmentally friendly water-based nano-inhibitor containing nano TiO2 was prepared in this work. The open-circuit potential-time curve revealed that the volt-age stability value of the steel coated with the proposed inhibitor is-0.51 V, which is higher than-0.54 V of the blank steel plate and commercial inhibitor (-0.52 V), indicating that the proposed nano-inhibitor can improve the stability of the entire system. According to the Tafel polarization curve, the inhibitor coating can significantly increase the corrosion potential, and at the same time reduces the corrosion current density. The EIS plots show that the proposed inhibitor can increase the charge transfer resistance.(c) 2023 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

This study delves into the multifaceted effects of multi-walled carbon nanotubes (MWCNT) incorporation on phosphogypsum's properties. We investigated the phase composition and morphology of phosphogypsum and observed the influence of MWCNT on the setting time, flexural strength, compressive strength, water resistance, and hydration process. The results demonstrated that MWCNT significantly abbreviates the setting time of phosphogypsum, enhances its absolute dry flexural strength and compressive strength, and improves water resistance, with optimal effects occurring at a MWCNT content of around 1.00%. Nonetheless, these benefits diminish and can even be counterproductive if MWCNT content is excessively high. The enhanced properties of phosphogypsum upon MWCNT addition can be ascribed to the filling effect and mechanical interlocking facilitated by MWCNT. Additionally, MWCNT promoted the hydration of phosphogypsum, as evidenced by calorimetric measurements.

Noble metal-nitrogen co-doped asphalt-based carbon nanocomposites were prepared by introducing noble metal salts using nitrogen-rich asphalt as a precursor and sodium chloride as a template. The effects of noble metal type and doping amount on the catalytic activity of the electrochemical CO 2 reduction reaction of asphalt-based carbon materials were investigated. The electrochemical performance tests showed that the 1% doped nanocomposite catalyst had the best results in 0.5 M of KHCO 3 solution containing saturated CO 2 . In addition, the results compared with those of the N 2 solution (starting voltage: -1.75 V, reduction current: -0.5 mA) also indicated that the catalyst effectively inhibits the hydrogen precipitation reaction during CO 2 reduction. Electrochemical impedance tests further validated the results of cyclic voltammetry tests. The results showed that the catalyst had the fastest surface charge migration rate with the highest electrocatalytic activity. CO 2- intermediate plays a key role in CO 2 reduction. HCO 3- is involved in the reaction and has a specific promotion effect on the reaction, and its concentration and reaction rate are positively correlated.