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Strong and ductile materials that have high resistance to corrosion and hydrogen embrittlement are rare and yet essential for realizing safety-critical energy infrastructures, hydrogen-based industries, and transportation solutions. Here we report how we reconcile these constraints in the form of a strong and ductile CoNiV medium-entropy alloy with face-centered cubic structure. It shows high resistance to hydrogen embrittlement at ambient temperature at a strain rate of 10 −4  s −1 , due to its low hydrogen diffusivity and the deformation twinning that impedes crack propagation. Moreover, a dense oxide film formed on the alloy’s surface reduces the hydrogen uptake rate, and provides high corrosion resistance in dilute sulfuric acid with a corrosion current density below 7 μA cm −2 . The combination of load carrying capacity and resistance to harsh environmental conditions may qualify this multi-component alloy as a potential candidate material for sustainable and safe infrastructures and devices. Strong and ductile materials with resistance to both corrosion and hydrogen embrittlement remain rare and yet are essential for hydrogen-propelled industries. Here, the authors show that a CoNiV medium-entropy alloy with face-centered cubic structure fulfils all the above criteria.

Aims An in-depth understanding of the relationship between the theoretical carrying capacity of grasslands and the forage-livestock balance is crucial for maintaining ecological equilibrium in grasslands and guiding ecological engineering. However, the spatiotemporal patterns of these two parameters in the arid mountainous region of the Qilian Mountains (QLMs) in China remain unclear. Methods The Carnegie-Ames-Stanford approach (CASA) model was employed to estimate the theoretical carrying capacity. The grazing pressure index, which represents the ratio of the actual to theoretical carrying capacity, was used to assess the forage-livestock balance. Results From 2000 to 2018, the theoretical carrying capacity of grasslands in the QLMs showed a significant ( p  < 0.01) increasing trend (0.011 ± 0.002 standard sheep unit (SU)·ha −1 ·yr −1 ), with an average value of 0.73 ± 0.7 SU·ha −1 . Its spatial distribution was high in the southeast and low in the northwest of the QLMs. The total annual precipitation of 72.1% in the grasslands was significantly and positively correlated with the theoretical carrying capacity ( R  = 0.45; p  < 0.05). The average grazing pressure index of natural grasslands in the QLMs was 2.08 ± 0.14, indicating that the grasslands were generally overloaded. The value increased significantly ( p  < 0.05) from 2000 to 2010 but has been decreasing significantly since 2011. Spatially, overloading was more severe in the southeastern counties. Conclusion Precipitation was the main factor responsible for the increase in the theoretical carrying capacity of the grasslands. In future grassland management, the red early-warning zones exhibiting continuously increasing overloading should be prioritized.

In many regions and at the planetary scale, human pressures on the environment exceed levels that natural systems can sustain. These pressures are caused by networks of human activities, which often extend across countries and continents due to global trade. This has led to an increasing requirement for methods that enable absolute environmental sustainability assessment (AESA) of anthropogenic systems and which have a basis in life cycle assessment (LCA). Such methods enable the comparison of environmental impacts of products, companies, nations, etc, with an assigned share of environmental carrying capacity for various impact categories. This study is the first systematic review of LCA-based AESA methods and their applications. After developing a framework for LCA-based AESA methods, we identified 45 relevant studies through an initial survey, database searches and citation analysis. We characterized these studies according to their intended application, impact categories, basis of carrying capacity estimates, spatial differentiation of environmental model and principles for assigning carrying capacity. We then characterized all method applications and synthesized their results. Based on this assessment, we present recommendations to practitioners on the selection and use of existing LCA-based AESA methods, as well as ways to perform assessments and communicate results to decision-makers. Furthermore, we identify future research priorities intended to extend coverage of all components of the proposed method framework, improve modeling and increase the applicability of methods.

Rockbolts are widely used in the tunnels and underground mining industry for support and reinforcement of the rock mass around the perimeter of the excavation. Better understanding of the load transfer mechanisms of rockbolts could improve rockbolt technology. Current rockbolt testing generally focuses on axial loading of the rockbolt, with shear loading of rockbolts only becoming more prevalent in the last 10–15 years. This research experimentally investigated the load-carrying capacity of five new rockbolts under axial and shear loadings, of which three were friction bolts and two were yielding bolts. Testing was undertaken using high strength concrete blocks to simulate a homogenous rock mass. The yielding style rockbolts provided considerably more tensile load capacity and deformation compared to the inflatable rockbolts; however, the inflatable rockbolts have the ability to deform significantly more in shear than in tension and have similar shear deformation as the yielding-style rockbolts. This research contributes to the understanding of the performance of the new inflatable and yielding rockbolts in different loading conditions and hence provided a benchmark for comparison with other existing friction and yielding bolts. Ultimately, the addition of these new rockbolts in the ground support community would give the site engineers more options to properly select the most suitable rockbolt under varying geotechnical conditions.HighlightsThe inflatable rockbolts (Hydrabolt) performed similarly and could hold peak loads of up to 82-107 kNIn shear loading situations the inflatable rockbolt can achieve peak shear loads up to 91-121 kN.The MP1 Bolt could achieve a maximum tensile load of 273-308 kN while deforming up to 132-135 mm.PAR1 Resin Bolt achieved maximum tensile load of 232-238 kN while deforming up to 148-176 mm.The shear load capacity of the inflatable bolts is greater than the tensile load capacity.

This study inspects the viability of engaging the discarded paper wastes in concrete by varying the volume proportions from 0%–20% with each 5% increment in replacement of the weight of cement. A physiomechanical study was conducted, and the results were presented. A glass fiber reinforced rectangular slab with a longer span (ly) to shorter span (lx) ratio of (ly: lx) 1.16 was cast with optimum replacement of waste-paper mass and compared the force-deformation characteristics with the conventional concrete slab without waste paper. The optimum percentage of discarded papers for the replacement of cement is 5%. Also, the results imply that the compressive strength at the age of 28 days is 30% improved for the optimum replacement. Based on the outcomes of the investigation, it can be inferred that the compressive strength gets progressively reduced if the volume of the discarded paper gets increases. The incorporation of glass fibers improves the split and flexural strength of the concrete specimens considerably. The ultimate load-carrying capacity of the glass fiber reinforced waste paper incorporated concrete slab measured 42% lower than that of the conventional slab. However, development of the new type of concrete incorporating waste papers is the new trend in ensuring the sustainability of construction materials.

To quantitatively evaluate and diagnose the carrying capacity of regional water resources under uncertain conditions, an index system and corresponding grade criteria were constructed from the perspective of carrying subsystem. Meanwhile, an improved entropy weight method was used to determine the objective weight of the index. Then, an evaluation model was built by applying set pair analysis, and a set pair potential based on subtraction was proposed to identify the carrying vulnerability factors. Finally, an empirical study was carried out in Anhui Province. The results showed that the consistency among objective weights of each index was considered, and the uncertainty between the index and grade criterion was reasonably dealt with. Furthermore, although the carrying situation in Anhui was severe, the development tended to be improved. The status in Southern Anhui was superior to that in the middle area, and that in the northern part was relatively grim. In addition, for Northern Anhui, the fewer water resources chiefly caused its long-term overloaded status. The improvement of capacity in the middle area was mainly hindered by its deficient ecological water consumption and limited water-saving irrigation area. Moreover, the long-term loadable condition in the southern part was due largely to its relatively abundant water resources and small population size. This evaluation and diagnosis method can be widely applied to carrying issues in other resources and environment fields.

Estimating the ecotourism carrying capacity (ETCC) in protected areas (PAs) is essential for minimizing the negative impacts of ecotourism and sustainable environmental management. PAs are one of the prominent ecotourism locations and many of these areas have been created to protect biodiversity and improve human wellbeing. This study has identified and prioritized negative impacts of ecotourism in Lar national park, the Jajrud protected area with the sustainable use of natural resources, and Tangeh Vashi national natural monument. For this purpose, physical carrying capacity (PCC), real carrying capacity (RCC), and effective carrying capacity (ECC) were estimated using the ETCC model. The results indicated that due to these areas’ ecological sensitivity, the most negative impacts of ecotourism are related to the environmental-physical dimensions. In contrast, the lowest impacts have been observed in the economic-institutional dimensions. Moreover, the results revealed that the highest PCC is related to Lar national park, and the lowest PCC is associated with Tangeh Vashi natural monument. There are more tourists in the Jajrud protected area with the sustainable use of natural resources than other areas in RCC and ECC due to low levels of restrictions and legal instructions. In contrast, in Lar national park and Tangeh Vashi natural monument, due to the short duration of ecotourism in these areas (from June to October), high level of restrictions, and ecological sensitivity, the number of tourists is less than the RCC and ECC. As these areas have a limited ability to attract visitors and ecotourism, the protection of these areas requires the implementation of sustainable management to control the negative impacts of ecotourism and estimate the number of visitors.

This paper presents a non-linear finite element model (FEM) to predict the load-carrying capacity of three different configurations of elliptical concrete-filled steel tubular (CFST) short columns: double steel tubes with sandwich concrete (CFDST), double steel tubes with sandwich concrete and concrete inside the inner steel tube, and a single outer steel tube with sandwich concrete. Then, a parametric and analytical study was performed to explore the influence of geometric and material parameters on the load-carrying capacity of elliptical CFST short columns. Furthermore, the current study investigates the effectiveness of machine learning (ML) techniques in predicting the load-carrying capacity of elliptical CFST short columns. These techniques include Support Vector Regressor (SVR), Random Forest Regressor (RFR), Gradient Boosting Regressor (GBR), XGBoost Regressor (XGBR), MLP Regressor (MLPR), K-nearest Neighbours Regressor (KNNR), and Naive Bayes Regressor (NBR). ML models accuracy is assessed by comparing their predictions with FE results. Among the models, GBR and XGBR exhibited outstanding results with high test R 2 scores of 0.9888 and 0.9885, respectively. The study provided insights into the contributions of individual features to predictions using the SHapley Additive exPlanations (SHAP) approach. The results from SHAP indicate that the eccentric loading ratio (e/2a) has the most significant effect on the load-carrying capacity of elliptical CFST short columns, followed by the yield strength of the outer steel tube ( ) and the inner width of the inner steel tube ( ). Additionally, a user interface platform has been developed to streamline the practical application of the proposed ML.

Resources and land carrying capacity are vital to the survival and development of human society and form the foundation for ensuring food security. However, evaluating land carrying capacity solely based on grain production is overly simplistic. A comprehensive assessment from the perspective of dietary nutrition is needed to more accurately reflect the actual carrying capacity of land. This study evaluates the land carrying capacity of Fujian Province from the perspectives of three major nutrients: calories, protein, and fat, using statistical data from 2007 to 2022. It employs models such as the nutrient supply model, land carrying capacity model, center of gravity model, and grey prediction model to evaluate the land carrying capacity situation in Fujian Province during 2007–2022 and to predict the trends in land carrying capacity from 2023 to 2032. The results indicate that, during the study period, the following were observed: (1) Total food production in Fujian Province significantly increased, primarily dominated by plant-based foods, though there has also been a proportional increase in animal-based foods, demonstrating distinct regional production characteristics. (2) The overall supply of food nutrients in Fujian Province rose, with the greatest increase observed in fat supply. The main sources of nutrients are grains, meat, and aquatic products. (3) The land carrying capacity of Fujian Province, viewed through different nutrient perspectives, has increased, with the southeastern region exhibiting a higher carrying capacity compared to the northwest. Over time, the spatial imbalance in land carrying capacity has decreased, with the centroid shifting from south to north. (4) The degree of nutrient restriction in Fujian Province has decreased, leading to an improvement in of land carrying capacity, with fewer constraints observed in inland cities. Xiamen and Quanzhou face triple nutrient restrictions, Fuzhou and other areas face dual restrictions, Zhangzhou faces single restrictions, while the remaining cities have sufficient nutrient availability. The comprehensive land carrying capacity index of Fujian Province has improved, transitioning from a “critical overload” to an “excess of balance” state. (5) From 2023 to 2032, both the land carrying capacity and the resident population of Fujian Province are predicted to increase. While the constraint on protein will weaken, constraints on fat and calories will remain significant. The land carrying capacity is expected to remain in a state of “critical overload”, with the conflict between people and land continuing to be severe.

Channel-forming discharge ( D cf ) is an important parameter in river management and reservoir flood regulation. Applying the methods for calculating D cf to reaches downstream reservoirs characterized by drastic changes in water and sediment conditions and long-term scouring status is difficult. Based on the riverbed-shaping principle of sediment-laden water flow, while simultaneously considering the active action of water flow and response of the riverbed, this study proposes a new method for calculating D cf by identifying the extreme value of the suspended sediment-carrying capacity index. The application of this method to the middle and lower reaches of the Yangtze River showed that after the impoundment of the Three Gorges Reservoir, D cf in this section was reduced by an amplitude between 2500 and 4700 m 3 /s. The results can be used to guide the operation of the Three Gorges Reservoir and the management of the middle and lower reaches of the Yangtze River, thus providing reference for other river channels downstream of the reservoir.