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【Objective】 The cavity chamber is a crucial component in double-suction pumps, and its design directly impacts pump performance. This study investigates the influence of key design parameters of the chamber on the efficiency of double-suction centrifugal pumps, aiming to optimize its design to enhance hydraulic performance of the pumps. 【Method】 Based on the principle of minimizing hydraulic loss, we designed the shapes of the chamber and the internal flow passages in the volute. We then examined the evolution of the cross-sectional area of the flow passages. Computational fluid dynamics (CFD) was used to compare the flow and performance characteristics of the pump before and after the optimization. The improved performance of the optimized design was evaluated against experimental results obtained from physical models. 【Result】 Compared to the original design without optimization, the optimized design increased efficiency of the pump at rated operating conditions by 3.36%. Within the range of 0.7 QBEP (design condition) to 1.2 QBEP, the optimized design improved overall pump efficiency compared to that without optimization. The optimization reduced the hydraulic losses across the volute significantly, with the reduction exceeding 20% under most operating conditions. At 1.3 QBEP, the reduction was 6.18%. For the chamber, the hydraulic losses in the optimized model were lower than those in the original model without optimization when flow rate exceeded 0.98 QBEP. 【Conclusion】 The optimized design of the suction chamber and the internal flow passages in the volute significantly improves flow stability in the suction chamber, eliminates vortices near the impeller outlet, reduces hydraulic losses, and enhances the hydraulic efficiency of the double-suction pumps.

The current cultivated land quality (CLQ) evaluation method fails to consider the determination of soil nutrients, resulting in the low efficiency of soil nutrient message extraction. In an effort to effectively solve the above problems, combined with the spatial variation of soil nutrients (SVSN) at the field scale, a CLQ evaluation method is proposed. The soil nutrients were determined according to the soil spatial variation analysis, and the soil color was standardized. The characteristic bands were determined by soil fertility and nutrients such as nitrogen, phosphorus, and potassium, and the soil nutrient message was preprocessed. On this basis, the soil nutrient message extraction model was constructed. According to the damage principle of subsoiling shovel, the limit value of the membership function of the CLQ exponent is determined, and the weighted sum method is used to calculate the CLQ exponent, so as to realize the SVSN and the evaluation of CLQ at the field scale. The experimental results show that the dimensional autocorrelation of soil bulk density and soil water content in different soil layers is high and that of capillary porosity, non-capillary porosity, and total porosity in different soil layers is strong.

【Objective】 Changes in density and hydraulic conductivity of soil not only modulate subsurface hydrological processes but also affect root growth and root uptake of water and nutrients from soil. Understanding the mechanisms underlying their changes is thus critical to mitigating flooding and improving bioavailability of soil water. In this paper we studied how wetting-drying cycles often seen in the field change bulk density and saturated hydraulic conductivity of the soil. 【Method】 Intact (mimicking zero-tillage) and disturbed (mimicking tillage) soil samples were taken from a cropped field. They were then subject to wetting-drying at different frequencies. During and at the end of the wetting-drying cycle experiment, we measured bulk density and saturated hydraulic conductivity of each soil sample. 【Result】 Bulk density of the intact and disturbed soil samples varied in the range of 1.41~1.89 g/cm3 and 1.47~1.85 g/cm3 respectively. The bulk density of intact soils after the first wetting-drying cycle increased significantly followed by slight fluctuations in other wetting-drying cycles, with an average coefficient of variation 8%. In contrast, bulk density of the disturbed soils increased with the increase in wetting-drying cycles, with an average coefficient of variation 5%. Overall, the wetting-drying cycles affected the bulk density of intact soils more significantly than the disturbed soils (P

Fully biodegradable mulch film enhances temperature and moisture retention during the early stages of maize growth while naturally degrading in the later stages, providing an environmentally friendly alternative to conventional plastic mulch films. However, there is no consensus on its impact on maize growth and yield. The present study utilized field test data from spring maize covered with fully biodegradable mulch film in the Xiliaohe Plain, aiming to improve the Decision Support System for Agrotechnology Transfer (DSSAT) model while focusing on soil temperature, irrigation, rainfall, and evapotranspiration. The parameters of the DSSAT model were calibrated and validated using field test data from 2016 to 2018. The improved DSSAT model accurately simulated the maize growth process under various induction periods of fully biodegradable mulch film. The simulation accuracy of this model was as follows: MRE < 10%, nRMSE < 12%, and R2 ≥ 0.80. Moreover, the yield of spring corn covered with fully biodegradable mulch film was predicted using meteorological data from 2019 to 2023. This study suggests that regions such as the Xiliaohe Plain, which share climatic conditions, should opt for fully biodegradable mulch film with an induction period of approximately 80 days to ensure high yields across different hydrological years. [ABSTRACT FROM AUTHOR]

Water stress (drought and waterlogging) is one highly important factor affecting food security in China. Investigating the effects of soil moisture stress on the morphological and physiological characteristics of maize seedlings is crucial for ensuring food production. The use of spectral monitoring to observe crop phenotypic traits and assess crop health has become a focal point in field crop research. However, studies exploring the contribution of crop phenotypic and physiological data to the Normalized Difference Vegetation Index (NDVI) are still limited. In this study, a 35-day pot experiment was conducted with seven soil moisture gradients: 50%, 60%, 70%, 80% (control group, CK), 90%, 100%, and 110% treatment. In order to investigate the effects of soil moisture stress on seedling phenotypes, antioxidant enzyme activities, and NDVI, an ASD FieldSpec 4 Hi-Res NG portable spectrometer was used to collect spectral data from maize (Zea mays L. B73) leaves. The contributions of maize phenotypic and physiological traits to NDVI were also examined. The results indicated that (1) the 50% and 110% treatments significantly affected maize seedling phenotypes compared to the CK group; (2) the activities of superoxide dismutase (SOD) and peroxidase (POD) in the leaves increased under water stress, while the activities of glutathione peroxidase (GSH-PX) and ascorbate peroxidase (APX) decreased; (3) soil moisture stress (drought and waterlogging) reduced photosynthetic pigments, chlorophyll content (SPAD), and NDVI, with inhibitory effects intensifying as the stress level increased; (4) Redundancy analysis showed that antioxidant enzymes explained 69.87% of the variation in seedling height, leaf area, and NDVI. Soil moisture stress, chlorophyll, and SPAD explained 58.14% of the variation in these parameters. The results demonstrated that maize seedlings were highly sensitive to soil moisture changes, and the SPAD value contributed significantly to NDVI (p < 0.01). This study provides valuable insights for future research in precision agriculture management [ABSTRACT FROM AUTHOR]

【Background】 The project of transforming drylands to paddy fields in Sanjiang Plain in the northeast China has increased its rice cultivation areas from 266 700 hm2 prior to the project to 1 733 300 hm2 after implementing the project. As a result, its demand for water also increased. Baoshan Farm is in the upper reach of Sanjiang plain on a piedmont, and its agricultural production had relied on groundwater since its establishment. Since 1992, it has gradually converted drylands to paddy field, and such a land conversion has resulted in a conflict between increased demand for water and limited water availability. 【Objective】 The purpose of this paper is to analyze how to optimize the use of surface water and groundwater to resolve the conflict between limited water supply and the increased demand for water due to the land use change, so as to avoid waterlogging while in the meantime alleviating continued groundwater table dropping. 【Method】 The calculation was based on groundwater flow with the groundwater dynamics under different managements simulated using the software Modflow-2000. The aquifer parameters, model validation and sensitivity analysis of the parameters were carried out using long-term hydrogeological data measured from the area. We then compared groundwater dynamics under irrigations using different combinations of surface water and groundwater. 【Result】 The calibrated groundwater dynamics model correctly reproduced the measured changes in groundwater level in the studied area; sensitivity analysis revealed that the initial groundwater level did not have a noticeable influence on long-term groundwater variation. Using the river water to irrigate areas 10 km in the proximity of the river while irrigating other areas using the groundwater can keep groundwater resource balance while in the meantime alleviating waterlogging. In contrast, irrigating too many areas using transferred river water could raise the groundwater table and result in waterlogging in a wide range of areas. 【Conclusion】 Rational use of groundwater and surface water in irrigation can maintain groundwater balance and avoid waterlogging in the farmlands of Baoshai; a monitoring system should be in place to timely measure the change in groundwater table.

Hair follicle (HF) regeneration during wound healing continues to present a significant clinical challenge. Dermal papilla cell-derived exosomes (DPC-Exos) hold immense potential for inducing HF neogenesis. However, the accurate role and underlying mechanisms of DPC-Exos in HF regeneration in wound healing remain to be fully explained. This study, represents the first analysis into the effects of DPC-Exos on fibroblasts during wound healing. Our findings demonstrated that DPC-Exos could stimulate the proliferation and migration of fibroblasts, more importantly, enhance the hair-inducing capacity of fibroblasts. Fibroblasts treated with DPC-Exos were capable of inducing HF neogenesis in nude mice when combined with neonatal mice epidermal cells. In addition, DPC-Exos accelerated wound re-epithelialization and promoted HF regeneration during the healing process. Treatment with DPC-Exos led to increased expression levels of the Wnt pathway transcription factors β-catenin and Lef1 in both fibroblasts and the dermis of skin wounds. Specifically, the application of a Wnt pathway inhibitor reduced the effects of DPC-Exos on fibroblasts and wound healing. Accordingly, these results offer evidence that DPC-Exos promote HF regeneration during wound healing by enhancing the hair-inducing capacity of fibroblasts and activating the Wnt/β-catenin signaling pathway. This suggests that DPC-Exos may represent a promising therapeutic strategy for achieving regenerative wound healing. [ABSTRACT FROM AUTHOR]