Search Results (29,497)

The capacity of biological self-healing concrete (BSHC) to repair cracks relies on the sustained viability and metabolic function of bacteria embedded within the concrete. BSHC structures face significant risk in cold climates due to low temperatures and freeze–thaw (FT) cycles, during which freezing water can generate internal pressure that damages bacterial cells and diminishes their activity. A special feature of this study is the incorporation of bacterial spores within expanded clay aggregates, tested under varying environmental conditions. The viability of bacterial spores was measured under cold and freeze–thaw cycles by counting colony-forming units, and a specific methodology was developed to assess the efficiency of self-healing under rain-simulated conditions. It was demonstrated that bacteria embedded in concrete could endure fluctuations in low temperatures and freeze–thaw cycles, compromising approximately 50% of viable spores. Also, it was found that water immersion during concrete curing can trigger early germination, decreasing viable spore counts by nearly tenfold. Ultimately, it was demonstrated that the healing of cracks in BSHC components is influenced by the conditions under which the specimens are incubated. The results suggest that BSHC can be employed in cold climate areas, given that suitable curing conditions and adequate bacterial protection within the concrete are ensured. Full article

Ladle furnace slag (LFS), a by-product of steel refining, shows a promising reuse pathway as an alternative additive or substitute for Portland cement due to its high alkalinity and similar chemical composition to clinkers. However, LFS is often stored in large, open surface areas, leading to many environmental issues. To tackle waste management challenges, LFS can be recycled as supplementary cementitious material (SCM) in many cementitious composites. However, LFS contains some mineral phases that hinder its reactivity (dicalcium silicate (γ-C₂S)) and pose long-term durability issues in the cured cemented final product (free lime (f-CaO) and free magnesia (f-MgO)). Therefore, LFS needs to be adequately treated to enhance its reactivity and ensure long-term durability in the structures of the cementitious materials. This literature review assesses possible LFS treatments to enhance its suitability for valorization. Traditional reviews are often multidisciplinary and explore all types of iron and steel slags, sometimes including the recycling of LFS in the steel industry. As the reuse of industrial by-products requires a knowledge of their characteristics, this paper focuses first on LFS characterization, then on the obstacles to its use, and finally compiles an exhaustive inventory of previously investigated treatments. The main parameters for treatment evaluation are the mineralogical composition of treated LFS and the unconfined compressive strength (UCS) of the final geo-composite in the short and long term. This review indicates that the treatment of LFS using rapid air/water quenching at the end-of-refining process is most appropriate, allowing a nearly amorphous slag to be obtained, which is therefore suitable for use as a SCM. Moreover, the open-air watering treatment leads to an optimal content of treated LFS. Recycling LFS in this manner can reduce OPC consumption, solve the problem of limited availability of blast furnace slag (GGBFS) by partially replacing this material, conserve natural resources, and reduce the carbon footprint of cementitious material operations. Full article

The article defines the morphometric, hydrochemical, and hydrobiological parameters of the Ust-Kamenogorsk reservoir, located on the territory of Ablaketka and the Bukhtarma reservoir, formed in the zone of narrowing of the mountain valley (1960), 12 km below the confluence of the Bukhtarma River with the Irtysh River. When determining deviations in indicators of the reservoirs, data from gauging stations have been taken into account. The purpose of the article is to conduct a comprehensive assessment of the current state of two large reservoirs in the East Kazakhstan region during the specified time period. The novelty of this topic lies in its comprehensive approach to assessing various aspects of the reservoirs’ condition in a specific region over a defined period. This approach enables the identification of current trends and issues and facilitates the proposal of practical measures to address them and enhance water resource management. As a result of this research work, after analyzing changes in indicators, the condition of the reservoirs was determined. During the research work, according to the results of hydrochemical studies, the Bukhtarma reservoir is favorable for the habitat of aquatic organisms, and in the Ust-Kamenogorsk reservoir, a positive change in hydrochemical parameters has been noted compared with 2020. In addition, after analyzing the research indicators, it was proposed to form specially protected areas in the Bukhtarma reservoir, suitable for use in connection with the distribution of valuable fish listed in the Red Book of the Republic of Kazakhstan. When demonstrating the location of gauging stations, methods of remote sensing of the earth and the method of geoinformation mapping were used. Full article

This study investigates the performance of sludge-added pervious concrete (SPC) at different curing temperatures by replacing some of the cement with activated sludge (AS). The results reveal that the incorporation of AS into pervious concrete had a favorable impact. At a curing temperature of 30 °C, the 28-day compressive strength and specific surface area reached 20.8 MPa and 9.14 m²/g, respectively, representing a 60% and 98.7% increase, in comparison to conventional concrete. Furthermore, the addition of AS to the concrete results in a notable reduction in the concentration of chemical oxygen demand (COD) in surface runoff water. The maximum rate of COD removal observed was 55.6%. A mechanism study revealed that the strength of concrete increased due to the reaction between reactive SiO₂ in AS and CaO in the aggregate. At a temperature of 30 °C, the microorganisms in the activated sludge fermentation process exhibit a higher production rate of fermentation gas, resulting in a greater escape of gas and an increase in the number of micropores in the permeable concrete. This leads to an enhanced specific surface area, which in turn exhibits a superior adsorption effect on COD. Full article

As an important ideal social practice in world history, the people’s commune system and its organized architectural activities took the first step in promoting rural modernization in modern China and had a significant impact on the built environment of urban and rural areas. This study aims to discuss how to view the legacy of rural people’s communes in service of contemporary society. Taking the Weixing Commune, which was the earliest established commune in China in 1958, as an example, through a comparative study of relevant planning and construction archives and the literature, combined with onsite investigations and through the perspective of the cultural landscape, this study delves into the history of local rural construction and sorts out the types, specific compositions, and value elements of the commune’s remains from four dimensions: environment, industry, architecture, and memory. The heritage of the people’s commune is unique. It was a comprehensive transformation of land to farmland, water conservancy, and other natural environmental patterns carried out by residents and related professionals to realize the ideal life of socialism and ultimately resulted in the shaping of a unique type of cultural landscape, presenting the coexistence of political landscapes that hold ideals and vernacular landscapes that carry life. Full article

This study presents an innovative approach to predicting the water level in the San Juan River, Chocó, Colombia, by implementing two hybrid models: nonlinear auto-regressive with exogenous inputs (NARX) and long short-term memory (LSTM). These models combine artificial neural networks with smoothing techniques, including the exponential, Savitzky–Golay, and Rauch–Tung–Striebel (RTS) smoothing filters, with the aim of improving the accuracy of hydrological predictions. Given the high rainfall in the region, the San Juan River experiences significant fluctuations in its water levels, which presents a challenge for accurate prediction. The models were trained using historical data, and various smoothing techniques were applied to optimize data quality and reduce noise. The effectiveness of the models was evaluated using standard regression metrics, such as Nash–Sutcliffe efficiency (NSE), mean square error (MSE), and mean absolute error (MAE), in addition to Kling–Gupta efficiency (KGE). The results show that the combination of neural networks with smoothing filters, especially the RTS filter and smoothed Kalman filter, provided the most accurate predictions, outperforming traditional methods. This research has important implications for water resource management and flood prevention in vulnerable areas such as Chocó. The implementation of these hybrid models will allow local authorities to anticipate changes in water levels and plan preventive measures more effectively, thus reducing the risk of damage from extreme events. In summary, this study establishes a solid foundation for future research in water level prediction, highlighting the importance of integrating advanced technologies in water resources management. Full article

The natural gas industry has developed rapidly in recent years, with gas storage playing an important role in regulating winter and summer gas consumption and ensuring energy security. The Ke7010 sand body is a typical edge water condensate gas reservoir with an oil ring, and the construction of gas storage has been started. In order to clarify the feasibility of synergistic storage building for gas injection and production, the fluid characteristics during the synergistic reservoir building process were investigated through several rounds of drive-by experiments. The results show that the oil-phase flow capacity is improved by increasing the number of oil–water interdrives, and the injection and recovery capacity is improved by increasing the number of oil–gas interdrives; the reservoir capacities of the high-permeability and low-permeability rock samples increase by about 4.84% and 7.26%, respectively, after multiple rounds of driving. Meanwhile, a numerical model of the study area was established to simulate the synergistic storage construction scheme of gas injection and extraction, and the reservoir capacity was increased by 7.02% at the end of the simulation period, which was in line with the experimental results. This study may provide a reference for gas storage construction in the study area. Full article

The release of polycyclic aromatic hydrocarbons (PAHs) by human energy exploitation and excessive environmental use has caused substantial environmental contamination. These compounds bioaccumulate in aquatic environments and translocate through the food chain, posing risks to health and environmental safety. To better understand the risks of PAHs in surface water and food chains, this review summarizes their distribution, concentration levels, sources, and toxicity in various surface water environments. It also examines how PAH bioaccumulation affects aquatic organisms and human health. Globally, PAHs have been detected in both aquatic environments and organisms with an increasing trend. Human activity is the main cause of PAH contamination. The results revealed a distinct geographical distribution of PAH risk influenced by population density, industrial development, climate, and seasonal variations. PAHs are found in remote areas, indicating their medium- and long-range transport by atmospheric dispersion. PAHs bioaccumulate in aquatic organisms and cause direct and indirect toxic effects via biomagnification. PAH bioaccumulation is directly correlated with aquatic pollution. This study also emphasizes the carcinogenicity of compounds such as benzo[a]pyrene, identifying occupational and environmental exposure frequencies as key risk factors. This study enhances our understanding of the dynamics of multiple PAHs in aquatic ecosystems and their health effects, thereby contributing to environmental sustainability. Full article

Small urban parks and green spaces, serving as essential recreational venues for city residents, also play a vital and irreplaceable role in maintaining urban biodiversity. It is of great importance to design and plan these areas in a way that integrates multiple habitats for various species while accommodating residents’ usage. This study, carried out at the Futian Mangrove Ecological Park located in Shenzhen, Guangdong Province, China, chose birds as indicator species to assess biodiversity within the park. Site inventory was undertaken from May to September 2022 and from October 2022 to April 2023. We quantitatively described the park’s habitats by examining primary environmental factors, along with 3 primary environmental factors and 11 secondary factors. A correlation analysis was then performed between these factors and bird diversity to gain insights into birds’ habitat preferences across different habitat types and at a finer scale of plant communities. Furthermore, bird clusters in the study case were categorized by foraging guilds and foraging patterns, and their distributions were studied at both the habitat patch scale and the plant community scale. Our findings reveal that, at the habitat patch scale, water surface area and grass coverage significantly positively impact bird diversity. At the plant community scale, plant communities with different structural characteristics vary in their importance to bird clusters with distinct characteristics. In areas with high human disturbance, shrub coverage is crucial for bird habitat protection. Additionally, we discovered that the impact of anthropogenic sound differs among bird species, highlighting the complexity of human disturbance factors on bird habitat preferences. Accordingly, we proposed several design recommendations aimed at enhancing bird diversity in parks, including increasing water body areas, reducing the distance between habitats and water surfaces, enhancing herbaceous plant coverage, and controlling anthropogenic sound. Full article

The highly hazardous chemical ammonia has been proven to be absorbed by nanoparticles, thereby exerting highly toxic effects on aquatic organisms. As a ubiquitous pollutant in aquatic environments, polystyrene nanomicroplastics (PSNPs) have shown strong adsorption capacity due to their large surface area. Therefore, the potential joint effects of ammonia and PSNPs need to be clarified. In this study, zebrafish embryos were exposed to a water solution with ammonia concentrations (0, 0.1, 1, and 10 mg/L) with or without PSNP (100 μg/L) treatment up to 120 hpf. The results showed that combined exposure increased the accumulation of ammonia and obviously reduced the locomotor speed of zebrafish larvae compared with exposure to ammonia alone. Further studies indicated that PSNPs can aggravate ammonia-induced neurotoxicity by altering the cholinergic system, dopaminergic neurons, and the retinal structure in zebrafish larvae. In addition, our results revealed that ammonia caused significant alterations in the expression of genes related to neurodevelopment and retinal development, and PSNPs exacerbated this adverse effect. In conclusion, PSNPs can aggravate ammonia-induced neurotoxicity in the early stage of zebrafish and their associated health risk to aquatic animals should not be underestimated. The main contribution of this article lies in revealing the synergistic neurotoxicity of ammonia and PSNPs in the early stage of zebrafish. Moreover; it emphasizes that the associated health risks to aquatic animals should not be underestimated. Full article

Native ectomycorrhizal fungi (ECMF) are generally more effective than non-native ECMF in facilitating the phytoremediation of heavy metal (HM) ions from contaminated soils. This study aimed to investigate the contributions of four ECMF species—Suillus luteus, Suillus flavidus, Suillus variegatus, and Gomphidius glutinosus—that were isolated from mining areas to the growth, water status, photosynthesis, and metallothionein gene expression of Populus alba exposed to varying concentrations of lead (Pb). The experiment lasted two months and involved P. alba cuttings subjected to Pb concentrations of 0, 200, and 400 mg kg⁻¹, representing no Pb stress, moderate Pb stress, and severe Pb stress, respectively. Results indicated that S. flavidus significantly enhanced the growth, water status, photosynthesis parameters, and metallothionein gene expression of P. alba under Pb stress, whereas S. luteus only exhibited positive effects under severe Pb stress. S. variegatus negatively affected the growth, water status, photosynthesis, and metallothionein gene expression of P. alba under Pb stress, while no significant difference was observed between the control treatment and G. glutinosus symbiosis. Therefore, S. flavidus and S. luteus are promising ECMF species for ecological restoration in mining areas, especially in P. alba woodlands. Full article

The consumption of contaminated water contributes to the global burden of diarrhea and other water-borne diseases, especially among young children. While decentralized solar water disinfection treatment systems (hereafter SODIS) remain a viable option to have safe drinking water, our understanding of the effects of household water treatment before use on willingness to accept and adopt a SODIS is limited. In this study, a complementary log-log regression analysis of the compositional and contextual factors that systematically vary with willingness to accept and adopt a SODIS in the Sawla-Tuna-Kalba (STK) district of Ghana was carried out. Based on our findings, a greater proportion of households (97%) are willing to accept and adopt a SODIS. Compositional and contextual factors such as age, marital status, education, religion, and geographical location significantly contribute to households’ willingness to accept and adopt a SODIS in the STK district of Ghana. Households that treat their water before use (66%, p < 0.05) are more likely to accept and adopt a SODIS compared to those that do not treat their water before use. The findings, therefore, suggest that scaling up SODIS in the STK district is sacrosanct and highlight the necessity to analyse compositional and contextual factors influencing willingness to accept and adopt SODIS. Our findings will inform policies and programs aimed at implementing SODIS in the study area to improve the health of communities that rely on poor-quality drinking water sources. Full article

By the end of the decade, the world population is expected to increase by nearly one billion people, posing challenges to meeting global food demand. In this scenario, soybean production is projected to increase by 18% within this decade. Despite being the largest soybean producer, responsible for over 40% of soybeans produced worldwide, drought events often impair Brazilian production. The goals of the present research were to quantify soybean yield losses related to drought in Brazil from 1973 to 2023 at national, state, and municipal levels and to assess the spatial distribution of losses across the production areas. The hypothesis investigated is that year-to-year variations in soybean yield are closely related to water availability, considering that crop management practices are constant from year to year, while increments in soybean yield across time (more than five years) relate tightly to better crop management practices and breeding improvements. Thus, quantifying year-to-year yield losses might demonstrate the effects of water availability on soybean yield. Yield data from the 1976/1977 to 2022/2023 crop seasons from the 26 states and the Federal District came from the National Supply Company, while the Brazilian Institute of Geography and Statistics supplied yield data for the 1973/1974 to 2020/2021 crop seasons from 1998 municipalities with more than 14 crop seasons. Soybean drought yield losses were calculated for each cropping season individually at the municipal, state, and national levels, based on the deviation in the observed yield to the corresponding maximum yield in the five-year window, considering that crop management practices and genetics represent a regular increment in soybean yield, which means that production practices improved over time and deviations from year to year are mainly related to drought occurrence. Annual soybean yield loss (expressed in tons, USD, and percentage), frequency of yield loss, and severity of yield loss were calculated at national, state, and municipal levels for each cropping season. The Standardized Precipitation Index (SPI), acquired from the Brazilian Weather Forecast and Climate Studies Center at the National Space Research Institute, was used as a qualitative indicator to corroborate the assessed soybean yield losses related to drought. The results demonstrate yield losses in more than 50% of crop seasons at the national level, with a similar frequency across the five decades, albeit with lower severities in the last 30 years. The Central–West region was more stable than the South region, with yield losses of up to 74%. In five decades, yield losses related to drought events stand at 11.65%, corresponding to 280 million tons or USD 152 billion (considering the average soybean price in 2022 at the Chicago Board of Trade). At the municipal level, analogous behavior was observed across time and space. The outcomes from the present research might subsidize public and corporative policies related to agricultural zoning, farm loan programs, crop insurance contracts, and food security, contributing to higher agricultural, environmental, economic, and social sustainability. Full article

Rainwater pumping stations located near urban centers or agricultural areas help prevent flooding by activating an appropriate number of pumps with varying capacities based on real-time rainwater inflow. However, relying solely on rule-based pump operations that monitor only basin water levels is often insufficient for effective control. In addition to maintaining a low maximum water level to prevent flooding, pump operation at rainwater stations also requires minimizing the number of pump on/off switches. Reducing pump switch frequency lowers the likelihood of mechanical failure and thus decreases maintenance costs. This paper proposes a real-time pump operation method for rainwater pumping stations using Deep Reinforcement Learning (DRL) to meet these operational requirements simultaneously, based only on currently observable information such as rainfall, inflow, storage volume, basin water level, and outflow. Simulated rainfall data with various return periods and durations were generated using the Huff method to train the model. The Storm Water Management Model (SWMM), configured to simulate the Gasan rainwater pumping station located in Geumcheon-gu, Seoul, South Korea, was used to conduct experiments. The performance of the proposed DRL model was then compared with that of the rule-based pump operation currently used at the station. Full article

Concrete production has increasingly used seawater to overcome the challenge of freshwater scarcity. Although the use of seawater in concrete still has a controversial reputation, it is a promising application, particularly when combined with mineral admixtures such as natural zeolitic tuffs (ZT). This paper aims to investigate the effect of using locally quarried ZT on the strength of unreinforced concrete mixed and/or cured using seawater. The mix proportions of the concrete were selected to obtain the optimum combination for the M20 grade of concrete with a water-to-cement ratio of 0.69. Moreover, 150mm-cubes and cylinders of 100 mm diameter by 200mm height were cast from the concrete mixtures, which contain 0%, 5%, 7.5%, 10%, and 25% of ZT as a partial replacement of silica sand. Splitting tensile tests and compressive strength tests were conducted on these specimens at 7, 28, and 90 days. The results show the harmful effect of seawater on the strength of plain concrete (without ZT) at 7, 28, and 90 days of curing, especially when seawater is used in both mixing and curing of the concrete. However, adding ZT in seawater-based concrete improved its strength apparently, especially at early curing ages. For example, using 10% of ZT as a partial replacement of silica sand increased the compressive strength of seawater based-concrete by 105.4%, 28.3%, and 34.6% after 7, 28, and 90 days of curing, compared with concrete without ZT and produced using seawater. These results contribute to the enhancement of the sustainability of both freshwater and concrete material through the use of ZT in producing concrete, particularly in areas where freshwater is scarce or expensive. Full article