Search Results (629)

As freshwater resources become increasingly scarce, seawater and brackish water represent alternative sources for crop irrigation, particularly in systems such as saltwater aquaponics. Red orache (Atriplex hortensis var. rubra) is a halophyte with high antioxidant content but also accumulates antinutrients like nitrate (NO₃⁻) and oxalate. Oxalate helps plants cope with salinity stress but can cause health issues in humans. This study examined the growth of red orache baby greens in saline and nitrogen-limited hydroponic solutions to assess its adaptability and nutritional quality, focusing on the impact of salinity and reduced nitrogen on antinutrient levels. Four nutrient solutions differing in NaCl (0 or 428 mM) and NO₃⁻ (10 or 1 mM) were tested. Salinity significantly reduced red orache yield (by 75.5%), pigment levels, antioxidants, and nutrient uptake, while increasing leaf Na and oxalate concentration, ethylene production, and succulence. Salinity decreased NO₃⁻ concentration and oxalate oxidase (OxO) activity but boosted total ascorbic acid and oxalate accumulation. Low NO₃⁻ mildly reduced yield (by 25.7%), leaf area, and NO₃⁻ concentration in leaves, but had no effect on leaf moisture content, succulence, antioxidant capacity, and the concentration of antioxidants, pigments, and total oxalate. In addition, low NO₃⁻ increased OxO activity, only under non-saline conditions. The high salinity typical of aquaculture effluents strongly reduced red orache baby greens yield and quality to a greater extent than low NO₃⁻ levels. Both salinity and low NO₃⁻ reduced NO₃⁻ concentration in leaves, while salinity increased oxalate concentration, probably due to the reduced activity of OxO. Full article

As climate conditions and agricultural technologies change, the soil seed bank may increase or decrease, which may affect the species composition and abundance of weeds in crops. The research was carried out in order to evaluate the influence of hillside parts on the number of viable seeds during different seasons (spring and autumn) in agrophytocenoses, which differ in the duration of the land’s covering with plants. Soil samples have been taken out in spring and autumn at the summit, midslope, and footslope of the hill. The time of the soil sample collection and covering of agrophytocenoses had a significant effect on soil seed numbers. In autumn, the average seed amount in the soil was higher by 6.38% than in spring. The largest seed number (in spring and autumn) was evaluated in the soil of cereal–grass crop rotation with a 2.0- and 6.9-times higher seed amount compared to the rotation with a row crop and permanent grassland. During the years, hill parts had a significant effect on the seed bank in autumn. In spring, the viable seeds comprised 67.10%, and in autumn, they comprised 65.33% of the total seed number. Significantly, the highest percentage of viable seeds was estimated in the footslope of the hill. This can be related to more favorable microclimatic conditions and higher soil moisture at the footslope, where more fertile soil and organic matter naturally accumulate, creating better conditions for seed viability preservation. Full article

The design of fiber-reinforced composite (FRC)-based components for marine energy applications necessitates a fundamental understanding of material properties and the resulting geometry to predict long-term performance. In this work, we present a modeling workflow to predict linear elastic and diffusive bulk properties at the mesoscale for an idealized geometry based on knowledge of fiber and resin properties. A parametric study was performed to identify the key model input parameters that influence bulk properties. Furthermore, we demonstrate how bulk properties can be leveraged in high-fidelity image-based simulations, where imperfections in tow geometry and voids captured during X-ray computed tomography imaging are explicitly represented within the simulation. Bulk properties of interest include moduli, Poisson’s ratios, hygroscopic swelling, diffusivity, and moisture uptake, which are key parameters for characterizing FRC performance within marine environments. Modeling predictions agreed well with experimental data, except for estimating swelling coefficients, likely due to crack accumulation as a function of moisture uptake. The mesoscale modeling workflow ultimately highlights a versatile framework for understanding the influence of material and geometric properties, which can be leveraged to rapidly assess new FRC-based components. Full article

In the Huang-Huai-Hai region, a high kernel moisture content remains a primary constraint for the mechanical harvesting of maize kernels. Recent studies have largely focused on the relationships among ear traits, meteorological factors, and kernel dehydration. However, the regulatory mechanisms underlying the influence of kernel microstructure and starch granule size distribution on dehydration characteristics remain unclear. In this study, the fast-dehydrating variety Jingnongke 728 (JNK728) and the slow-dehydrating variety Zhengdan 958 (ZD958) were selected as experimental materials to compare the varietal differences in kernel microstructure and starch granule size distribution, and to investigate their roles in regulating kernel dehydration characteristics. The results showed that JNK728 had a significantly higher kernel dehydration rate (KDR). Compared with ZD958, JNK728 exhibited average increases of 15.22% in the pre-physiological maturity dehydration rate (pre-KDR) and 97.72% in the post-physiological maturity dehydration rate (post-KDR). The higher accumulations of kernel total starch content and amylopectin content were also observed in JNK728. Kernels of JNK728 were characterized by thinner pericarp at 35 days after pollination (DAP), lower vitreousness and a higher proportion of floury endosperm. Additionally, JNK728 displayed more uniformly sized starch granules with smooth surfaces, wider intergranular spaces, and looser starch packing. Moreover, the volume, number, and surface area of large starch granules (≥10 μm) in JNK728, increased by 2.91%, 10.94%, and 4.95%, respectively. These findings enhance the understanding of the regulatory role of kernel microstructure and starch granule size distribution in dehydration characteristics, offering theoretical guidance for the development of mechanical maize kernel harvesting technologies in the Huang-Huai-Hai region. Full article

The sustainable management of urban grasslands is crucial for resilient city ecosystems. With increasing urbanization, improving soil quality to support turfgrass growth has become a priority. This study evaluates biochar produced from Paulownia leaves (PLB), a low-cost byproduct of Paulownia cultivation, as a growing medium amendment. Raw leaves (PL) and PLB were characterized by SEM, FTIR, and elemental analysis to assess physicochemical changes. A three-month pot experiment under outdoor conditions was conducted with turfgrass plots exposed to different irrigation and fertilization regimes. Growing medium pH, moisture, electrical conductivity, cation exchange capacity, nutrient availability, grass chlorophyll content, and uptake were monitored. The application of PLB improved the growing medium structure, raised the pH by up to one unit, and enhanced pigment accumulation in turfgrass samples. When combined with nitrogen fertilizer, PLB significantly increased turfgrass visual quality, whereas under limited irrigation, PLB alone improved seedling establishment compared to controls. Statistical analysis confirmed significant treatment effects by ANOVA, and PCA provided a precise classification of treatment groups. These findings indicate that PLB can improve nutrient efficiency, turfgrass resilience, and organic waste management. Full article

Lime-based repair mortars, plasters, and renders are widely utilized in the conservation of traditional buildings. Historically, considerable emphasis has been placed on ensuring that new repair mortars are aesthetically compatible with existing historic materials. However, comparatively less focus has been placed on ensuring hygric compatibility, which is critical to maintaining the moisture equilibrium of traditional masonry walls and preventing moisture accumulation caused by repair interventions. The FabTrads project examined the hygrothermal properties of newly fabricated quicklime mortars, prepared with binder-to-aggregate ratios of 1:2 and 1:4, alongside a range of historic lime-based mortars, plasters, and renders, sourced from buildings across Ireland. This paper presents a comparative analysis of their hygric behaviour. Experimental results indicate that the capillary absorption of the fabricated mortars correlates well with their historic counterparts. Both fabricated mortars exhibited vapour diffusion resistance factors within the range of the historic samples, albeit towards the higher end. Hygrothermal simulations of vapour and liquid water transport revealed that the moisture behaviour of the fabricated mortars is largely within the range of performance of their historic counterparts. Relative humidity was slightly elevated for the fabricated mortars in the models concerning vapour transfer. Notwithstanding this, the findings provide a reassuring indication that the hygric performance of fabricated quicklime mortars is comparable with that of traditional lime-based materials, supporting their appropriate use in conservation practices without adversely affecting the moisture dynamics of the building fabric. Full article

Compaction quality control in earthworks and pavements still relies mainly on density-based acceptance referenced to laboratory Proctor tests, which are costly, time-consuming, and spatially sparse. Lightweight dynamic cone penetrometer (LDCP) provides rapid indices, such as $q_{d0}$ and $q_{d1}$, yet acceptance thresholds commonly depend on ad hoc, site-specific calibrations. This study develops and validates a supervised machine learning framework that estimates $q_{d0}$, $q_{d1}$, and $Z_c$ directly from readily available soil descriptors (gradation, plasticity/activity, moisture/state variables, and GTR class) using a multi-campaign dataset of $n=360$ observations. While the framework does not remove the need for the standard soil characterization performed during design (e.g., W, ${\gamma }_{d,\mathrm{field}}$, and $R{C}_{\mathrm{SPC}}$), it reduces reliance on additional LDCP calibration campaigns to obtain device-specific reference curves. Models compared under a unified pipeline include regularized linear baselines, support vector regression, Random Forest, XGBoost, and a compact multilayer perceptron (MLP). The evaluation used a fixed 80/20 train–test split with 5-fold cross-validation on the training set and multiple error metrics ($R^2$, RMSE, MAE, and MAPE). Interpretability combined SHAP with permutation importance, 1D partial dependence (PDP), and accumulated local effects (ALE); calibration diagnostics and split-conformal prediction intervals connected the predictions to QA/QC decisions. A naïve GTR-average baseline was added for reference. Computation was lightweight. On the test set, the MLP attained the best accuracy for $q_{d1}$ ($R^2=0.794$, RMSE $=5.866$), with XGBoost close behind ($R^2=0.773$, RMSE $=6.155$). Paired bootstrap contrasts with Holm correction indicated that the MLP–XGBoost difference was not statistically significant. Explanations consistently highlighted density- and moisture-related variables (${\gamma }_{d,\mathrm{field}}$, $R{C}_{\mathrm{SPC}}$, and W) as dominant, with gradation/plasticity contributing second-order adjustments; these attributions are model-based and associational rather than causal. The results support interpretable, computationally efficient surrogates of LDCP indices that can complement density-based acceptance and enable risk-aware QA/QC via conformal prediction intervals. Full article

The processing of fine and technogenic chromite-bearing raw materials accumulated in tailings and sludge storage facilities is a key challenge for sustainable metallurgical development. This paper presents the results of laboratory and pilot-scale studies on the application of vibro-briquetting technology for flotation concentrates and waste materials from JSC “TNC Kazchrome” (ERG). For the first time in Kazakhstan, a pilot-scale validation of vibro-briquetting of flotation chromite concentrates was carried out, resulting in pilot confirmation of the vibro-briquetting technology. The optimal technological parameters of the process were established, and the effectiveness of various types of binders was evaluated. Pilot-scale trials demonstrated that the use of organic and mineral binders ensures the production of durable briquettes with a low yield of fines (around 2%). Comparison with conventional agglomeration technologies (pelletizing, sintering, roller-press briquetting, extrusion briquettes) highlighted the advantages of vibro-briquettes in terms of energy efficiency, environmental performance, and suitability for fine raw materials. It was shown that composite binders (lignosulfonate + cement) provide enhanced strength and water resistance in briquettes, as well as optimal conditions for strength development during thermal–moisture treatment. The findings confirm the high potential of vibro-briquetting technology in Kazakhstan as an energy-efficient and environmentally friendly solution for the integrated utilization of local chromite resources. The proposed vibro-briquetting technology makes it possible to process previously unused gravity and flotation tailings of chromite ores from the Kempirsai Massif, thereby improving the comprehensive utilization of mineral resources and reducing environmental impact. This development is of great importance for Kazakhstan’s industry, as it represents the first pilot-scale testing of cold vibro-briquetting technology for flotation concentrates. Full article

Reliable modeling and prediction of the long-term strength of materials are relevant, as they allow for accurate determination of the service life of structures and components made from these materials. The aim of this work is to develop models of the long-term strength of rheonomic materials under constant stress and step loading using the principle of damage accumulation, as well as a model for predicting their long-term strength under constant stress based on short-term test data. Using the developed models, the long-term strength of optical fiber with a moisture of 30% and 85% under constant stress from 1600 to 2100 MPa and aluminum alloy under a step change of stress at a temperature of 180 °C were predicted with high accuracy; the long-term strength of pearlitic steel was predicted based on short-term tests under constant stress at temperatures from 98 °C to 293 °C. The developed models have important practical significance, as they can be used for modeling and predicting the long-term strength of rheonomic materials in practice, particularly in cases where the conditions of their operation and loading history are known. Full article

Drought poses a severe challenge to ornamental tree growth under climate change. This study employed a 2 × 4 factorial design—with two soil moisture levels (80–85% vs. 50–55% field capacity) and four nitrogen treatments (NN: no nitrogen; NO: nitrate nitrogen; NH: ammonium nitrogen; MN: mixed nitrate-ammonium nitrogen)—to examine the efficacy of nitrogen addition in enhancing drought resistance in Machilus yunnanensis seedlings. Results revealed that (1) drought stress leads to the acidification of rhizosphere soil, resulting in a decrease of 7.67%, 29.51%, 14.07%, and 44.09% in the content of soil organic matter (SOM), available phosphorus (AP), available potassium (AK), and dissolved organic nitrogen (DON), respectively. This adverse change directly impacts plant growth; it is manifested by a significant reduction of 45% in total chlorophyll (T Chl), a 67.18% decrease in photosynthetic rate (Pn), as well as reductions of 10.61%, 27.59%, 14.81%, and 12.35% in plant height, leaf, stem, and total biomass, respectively. (2) The application of all three forms of nitrogen helps alleviate drought stress, as evidenced by the recovery of photosynthetic levels and the reduction in malondialdehyde (MDA) content, with ammonium-N exhibiting superior efficacy over nitrate-N across most metrics. (3) Strikingly, the mixed nitrogen form outperformed singular applications by demonstrating multifaceted advantages: It maintains soil pH levels and rhizosphere nutrient availability under drought conditions, particularly with a 10.99% and 33.44% increase in dissolved organic nitrogen and available phosphorus content, respectively. More importantly, under drought stress, it increased leaf water content by 20.31%, nitrogen use efficiency by 15.67%, and photosynthetic nitrogen use efficiency by 439.44%, promoted the accumulation of osmolytes, while upregulating antioxidant enzyme activity to counteract osmotic imbalance and alleviate oxidative damage. These findings highlight that nitrogen supplementation, particularly mixed nitrogen application, enhances drought resistance in M. yunnanensis, offering a viable management strategy to sustain urban tree landscapes in water-limited environments. Full article

This study analyzes winds over the Red Sea (17 N, 39.5 E) and consequences for the northeast African climate in early summer (May–July). As the Indian SW monsoon commences, NNW winds > 6 m/s are channeled over the Red Sea between 2000 m highlands, forming a low-level jet. Although sea surface temperatures of 30C instill evaporation of 8 mm/day and surface humidity of 20 g/kg, the air mass above the marine layer is dry and dusty (6 g/kg, 100 µg/m³). Land–sea temperature gradients drive afternoon sea breezes and orographic rainfall (~4 mm/day) that accumulate soil moisture in support of short-cycle crops such as teff. Statistical analyses of satellite and reanalysis datasets are employed to reveal the mesoscale structure and temporal response of NE African climate to marine winds via air chemistry data alongside the meteorological elements. The annual cycle of dewpoint temperature often declines from 12C to 4C during the Indian SW monsoon onset, followed by dusty NNW winds over the Red Sea. Consequences of a 14 m/s wind surge in June 2015 are documented via analysis of satellite and meteorological products. Moist convection was stunted, according to Cloudsat reflectivity, creating a dry-east/moist-west gradient over NE Africa (13–14.5 N, 38.5–40 E). Diurnal cycles are studied via hourly data and reveal little change for advected dust and moisture but large amplitude for local heat fluxes. Inter-annual fluctuations of early summer rainfall depend on airflows from the Red Sea in response to regional gradients in air pressure and temperature and the SW monsoon over the Arabian Sea. Lag correlation suggests that stronger NNW winds herald the onset of Pacific El Nino. Full article

This study investigated the mechanisms of soil water–salt and nitrogen transport and optimal strategies under freeze–thaw (F-T) cycles in the salinized farmlands of the Hetao Irrigation District. A combined approach of field monitoring and laboratory simulation, utilizing both undisturbed and repacked soil columns subjected to 0–15 F-T cycles and five irrigation treatments, was employed to analyze the spatiotemporal dynamics in Gleyic Solonchaks. The results demonstrated that freeze–thaw processes play an important role in salt migration in surface soil layers, driving salt redistribution through phase changes of soil moisture. Increased freeze–thaw cycles reduced surface soil moisture content while promoting upward salt accumulation, salt dynamics exhibited pronounced spatial heterogeneity and irrigation source dependency, and the surface layer exhibited lower salinity levels after irrigation compared to pre-irrigation levels. These cycles also enhanced short-term soil nitrogen transformation and facilitated inorganic nitrogen accumulation. Different irrigation regimes exhibited a significant impact on the dynamics of water–salt and nitrogen in soil, with low-salinity treatment (S2) and moderate-nitrogen irrigation (N2) effectively reducing surface salt accumulation while improving nitrogen utilization efficiency (moderate-nitrogen irrigation exhibited higher mineralization rates, which facilitated the release of inorganic nitrogen from soil). This study reveals the synergistic transport mechanisms of water–salt and nitrogen under freeze–thaw driving forces and provides a scientific basis and practical pathway for sustainable agricultural management in cold arid irrigation districts. Full article

This study presents a theoretical analysis of the effectiveness of the use of variatropic concretes in multi-layer panel structures of buildings in terms of heat transfer. Theoretical analysis was performed with the aid of the modern numerical modeling software package ELCUT 6.6 and the computer algebra system Maple, which helped improve the reliability of the calculations. The results of this study of the thermophysical parameters of multi-layer panels using variatropic concrete showed that an increase in the degree of variatropy contributes to a rise in the temperature on the inner surface of the panel from 17.94 °C (traditional panel) to 18.87 °C (the most variatropic panel, Scheme 4), which improves indoor comfort conditions and reduces the risk of condensation. Additionally, it is possible to reduce the thickness of the insulation layer without compromising thermal efficiency. The high thermal inertia (D > 7) of variatropic panels ensures the accumulation and retention of heat, which has a positive effect on energy consumption during the heating season. The moisture regime of the studied structures meets regulatory criteria for preventing moisture accumulation, thereby increasing panel durability and eliminating conditions for mold formation or structural degradation. The air permeability performance of the panels also complies with the standards, while the dense outer concrete layers provide additional protection against air infiltration, stabilizing both thermal and moisture balance. The calculated thermal resistance of variatropic panels (Schemes 3 and 4) exceeded the standard requirement (3.20 m²·°C/W) by 1.2 and 1.74 times, respectively. Thus, it was established that the application of the variatropic principle in panel design ensures a more rational distribution of temperature fields, which results in reduced heat losses and improved thermal stability of exterior enclosures. This approach develops new design solutions focused on improving the energy efficiency of buildings and reducing material costs, which is consistent with current trends in Functionally Graded Design (FGD). Full article

To investigate differences in water and salt transport during irrigation, freezing, and thawing periods in typical saline-affected paddy fields and saline-affected upland fields, field-based automated in situ monitoring was conducted in both types of saline-affected farmland (May 2023 to May 2024). Correlation analysis identified seasonal drivers of water–salt migration, while the HYDRUS-3D model simulated transport and equilibrium processes. The HYDRUS-3D model, equipped with a freeze–thaw module, accurately simulated complex water–salt transport in cold arid regions. Key findings include: (1) During freeze–thaw periods, soil moisture content and electrical conductivity (Ec) increased with the retreating frost front in both upland and paddy soils. During the irrigation period, maximum soil moisture content and Ec values occurred at 80 cm depth in dryland soils and 60 cm depth in paddy soils, primarily influenced by irrigation and capillary rise. (2) Groundwater salt ions significantly affected soil salinization in both farmland types. During the freeze–thaw period, Ec positively correlated with soil temperature. During the irrigation period, Ec positively correlated with evapotranspiration and negatively correlated with precipitation. (3) Salt changes during the irrigation, freezing, and thawing periods were −565.4, 326.85, and 376.55 kg/ha for upland fields, respectively; corresponding changes for paddy fields were −1217.0, 280.07, and 299.35 kg/ha. (4) Both land types exhibited reduced salinity during the irrigation period, with paddy fields showing a reduction 3.36 times greater than dryland fields. During the freezing and thawing periods, both land types experienced salinity accumulation, with dryland fields accumulating higher salinity levels than paddy fields. These results indicate that paddy field irrigation and drainage systems help mitigate salinization, while dryland fields are more prone to springtime salt accumulation. These findings provide a basis for developing targeted management strategies for saline–alkali soils. Full article

In the global agricultural production system, maintaining and improving soil quality are core elements for ensuring food security and sustainable agricultural development. As a key indicator of soil quality, the content and dynamic change in soil organic carbon have a profound impact on the physical, chemical and biological properties of soil, and play a decisive role in soil fertility, structural stability, water and fertilizer conservation capacity and microbial activity. However, its decomposition is slow, and a large number of straws returning to the field will impact crop growth; its combination with irrigation is a more reasonable solution, as it can significantly improve the soil environment, increase soil moisture and promote straw decomposition. Therefore, in order to further study the effects of different irrigation methods and straw-returning combinations on soil active-carbon content, an experiment was carried out in long-term arid and semi-arid areas under in-field corn cultivation during 2019–2020. Three irrigation modes were designed—flood irrigation (BI), shallow drip irrigation (SD) and drip irrigation under film (DP)—and straw returning (CS) and no straw returning (CK) were set up, with irrigation applied at critical corn growth stages (internode elongation, heading, bell mouth stage) to support plant growth. The results are as follows: (1) The content of soil organic carbon in different treatments had a gradual upward trend with the advance of growth period; the content of soil organic carbon in DP treatment was significantly higher than that in SD and BI treatment under the same straw returning mode, indicating that drip irrigation under film and straw-returning mode can synergistically improve soil fertility and organic carbon content. (2) Different irrigation methods and straw-returning methods have significant effects on the content of soil active organic carbon components. Different drip irrigation modes can significantly improve the content of soil POC and MBC compared with flood irrigation. The Kos of SD treatment is significantly higher than that of other irrigation treatments, and the CPMI is lower than that of the other two irrigation methods, indicating that the soil organic carbon of SD treatment is more stable. Therefore, under straw-returning conditions, drip irrigation can significantly improve the carbon content of soil components and the management index of soil carbon pool, thus significantly increasing the accumulation of soil organic matter. This study discussed the effects of straw returning on soil organic carbon composition and soil carbon pool index under different irrigation methods to provide theoretical and practical bases for the selection and promotion of straw-returning methods and rational irrigation methods in semi-arid areas. Full article