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Reinforced concrete (RC) walls are extensively used in civil air defense engineering and are susceptible to low-speed impacts with high energy and massive weight during service. Therefore, it is crucial to consider the impact resistance of these walls and explore effective protection methods. The honeycomb structure, known for its energy-absorbing properties, has been widely utilized in aerospace, automotive, and maritime industries. However, there is a need for more research on applying honeycomb structures in energy-absorbing protection devices in civil engineering. This study proposes the use of honeycomb sandwich panels to protect civil air defense RC walls, creating a Honeycomb Sandwich Panel Composite RC wall (HSP-RC wall). Through pendulum impact experiments, we investigated the dynamic response of RC walls, both standard and HSP-RC walls with varying honeycomb parameters, under high-energy impacts. The goal was to evaluate the impact resistance of these RC walls, analyze the deformation differences among different HSP-RC walls, and examine the influence of honeycomb parameters on the impact protection effectiveness. The research results indicate that honeycomb sandwich panels can provide impact protection for RC walls by absorbing energy, and their protection effect is related to the parameters of the honeycomb core layer. This research result can be applied to RC structures that bear impact loads, achieving effective protection for RC structures.

The steel tube-reinforced concrete (STRC) shear wall plays an important role in the seismic design of high-rise building structures. Due to the synergistic collaboration between steel tubes and concrete, they effectively enhance the ductility and energy dissipation capacity of conventional shear walls. To identify vulnerable areas prone to brittle failure and optimize the design, it is essential to develop a rapid method for identifying the failure mode of STRC shear walls. In this study, a fast identification method of STCR shear wall failure modes based on a Blending fusion model with Generative Adversarial Network (GAN) augmented data is proposed. The GAN is employed to address the issue of inadequate experimental data by generating new samples. This method combines classification boosting (Catboost), Random Forest (RF), K-Nearest Neighbors (KNN), and Least Absolute Shrinkage and Selection Operator (LASSO) to establish the Blending-CRKL fusion model to improve the prediction accuracy of the failure mode of STRC shear walls. The results reveal a significant improvement in the prediction performance of KNN, Backpropagation Neural Network (BPNN), RF, Light Gradient Boosting Machine (LightGBM), Catboost, and Blending-CRKL models after augmenting the training set with GAN. On average, the accuracy increased by 13%, precision increased by 81%, recall increased by 48%, and F1 score increased by 67%. The proposed Blending-CRKL fusion model outperforms the tested KNN, BPNN, RF, LightGBM, and Catboost models, achieving an accuracy rate of 97% in predicting the failure mode of STRC shear walls. Additionally, the stability and robustness of the Blending-CRKL model were validated, while the important features and value ranges of different failure modes were analyzed. This study provides a reference for the rapid identification of the failure mode of STRC shear walls.

As an essential regional planning policy, poverty alleviation relocation has a significant impact on the regional economy, environment, and social well-being and is critical for sustainable development. Based on the development of minority areas in Yunnan, this study improves the traditional sustainable livelihood analysis framework and constructed a livelihood capital evaluation system including natural, physical, financial, social, human, and cultural capital. Furthermore, the measurement standard of sustainable livelihoods is proposed, which requires not only the enhancement of livelihood capital but also the coupling and coordinated development of all capital components. Based on the data of Menglai township from 2015 to 2021, this study estimates that farmers’ livelihood capital has increased after relocation, and the level of coupling and coordination has improved. Still, it has yet to reach extreme coordination. Hereafter, the theoretical framework of internal and external factors affecting livelihood capital is constructed, and the influencing factors of livelihood capital are obtained through regression analysis. This study provides a new tool for evaluating livelihood capital in minority areas, obtains new findings on the sustainable development of farmers’ livelihood capital after poverty alleviation relocation, and expands a new perspective for studying the influencing factors of livelihood capital.

The harmless disposal of spent cathode carbon blocks (SCCBs) has become an urgent issue in the primary aluminum industry, and the disposal of SCCBs by co-combustion in pulverized coal boilers is expected to be the most effective treatment method. A muffle furnace at 815 °C was used in this study to perform a co-combustion experiment of meager coal and SCCBs. The ash fusion characteristics (AFTs), microscopic morphology, and minerals composition of co-combustion ash were characterized. The interaction mechanism of different mineral components and the change in AFTs and viscosity-temperature characteristics were investigated using FactSage software. Results show that the change in the ash deformation temperature (DT) is correlated linearly with the SCCB addition ratio, whereas other characteristic temperatures exhibit a nonlinear relationship. The contents of SiO2, Al2O3, and Na2O collectively determine the DT in the ash, and the influence degree from high to low is in the order of SiO2, Na2O, and Al2O3. The phase diagram of Na2O–Al2O3–SiO2 is used to accurately predict the changing trend of the melting point of co-combustion ash. The ratio changes between refractory and fusible minerals in the ash, as well as the degree of low-temperature eutectic reaction between sodium- and calcium-containing minerals, are the main factors affecting the melting point of ash. When the blending amount of SCCBs is 5%, mostly complete combustion is achieved, and slagging does not occur easily. The optimal blending ratio of SCCBs is obtained using the co-combustion method from the aspect of AFTs and viscosity-temperature characteristics. This work lays a theoretical foundation for industrial application.

Steel tube confined concrete (STCC) stub columns have great strength and facilitate construction. In this study, the axial compressive strength of an aluminum alloy tube confined concrete column with (ATCC-CHS) and without (ATCC) a circular hollow section was tested in laboratory experiments. The influence of concrete strength, diameter–thickness ratio and the hollow rate on the failure mode, ultimate compressive strength, strain, stiffness, constraint effects and ductility was quantified. The experiments showed that local buckling failure could be effectively delayed when the outer aluminum tube did not directly bear axial load. Columns without a circular hollow section had bearing capacities approximately 20% higher than those with a circular hollow section, though their ductility was poorer. The ultimate strength tended to increase with decreases in the hollow rate and diameter–thickness ratio. It tended to increase with increasing concrete strength, though stronger concrete also reduced ductility. The bearing capacities of the columns were calculated according to several proposed formulas and compared with the experimental results, and the proposed Teng and Attard’s formula appeared to be satisfactory.

Dielectric properties of materials influence the interaction of electromagnetic fields with and are therefore important in designing effective dielectric heating processes. We investigated the dielectric properties (DPs) of pecan kernels between 10 and 3000 MHz using a Novocontrol broadband dielectric spectrometer in a temperature range of 5−65 °C and a moisture content range of 10−30% wet basis (wb) at three salt levels. The dielectric constant (ε′) and loss factor (ε″) of the pecan kernels decreased significantly with increasing frequency in the radio frequency (RF) band, but gradually in the measured microwave (MW) band. The moisture content and temperature increase greatly contributed to the increase in the ε′ and ε″ of samples, and ε″ increased sharply with increasing salt strength. Quadratic polynomial models were established to simulate DPs as functions of temperature and moisture content at four frequencies (27, 40, 915, and 2450 MHz), with R2 > 0.94. The average penetration depth of pecan kernels in the RF band was greater than that in the MW band (238.17 ± 21.78 cm vs. 15.23 ± 7.36 cm; p < 0.01). Based on the measured DP data, the simulated and experimental temperature-time histories of pecan kernels at five moisture contents were compared within the 5 min RF heating period.

There is a constant drive to improve the properties of recycled concrete owing to its inferior strength and fracture toughness compared to normal concrete and recent progress in graphene oxide (GO) nanomaterials impelling nanosized reinforcements to recycled concrete. Here, GO-modified natural sand (NS)- or recycled sand (RS)-based mortars (GONMs or GORMs) with six GO fractions (wGOs) were fabricated to explore their 28 d mechanical strengths (f28t, f28c), fracture toughness (KIC, δc), and microhardness (Hv), as well as their crystal phases (using X-ray powder diffraction) and microstructures (using scanning electronic microscopy). Results reveal, greater enhancements in mechanical strengths (4.50% and 10.61% in f28t, 4.76% and 13.87% in f28c), fracture toughness (16.49% and 38.17% in KIC, 160.14% and 286.59% in δc), and microhardness (21.02% and 52.70% in Hv) of GORM with just 0.025 wt‰ and 0.05 wt‰ GO, respectively, with respect to the control are achieved when comparing with those of GONM with the same wGO. More zigzag surfaces, more irregular weak interface slips, and the relatively lower strengths of RS bring the superiority of the template and reshaping effects of GO into full play in GORM rather than in GONM. These outcomes benefit a wide range of applications of recycled concrete products.