Search Results (177)

To address the problems of short-circuit flow and dead zones, complicated operation and control caused by intermittent influent, and the mismatch between aeration rate and oxygen demand in the Cyclic Activated Sludge System (CASS), a novel Multi-Compartment Fixed-Biofilm Cyclic Activated Sludge System (MCFCASS) was developed. This system operated in continuous-flow mode, and the aeration rate of each compartment was redistributed using a mathematical model. The results show that the plug flow ratio of the MCFCASS reactor increased from 18.75% to 31.25% compared with the CASS reactor. After aeration rate redistribution, the average total nitrogen (TN) removal efficiency of the MCFCASS reactor rose from 83.34% to 86.80%, and the effluent TN concentration consistently met the Grade I-A limit (15 mg/L) specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). The average removal efficiencies of chemical oxygen demand (COD) and ammonium nitrogen (NH₄⁺-N) increased from 91.58% and 93.39% to 92.98% and 94.57%, respectively. Microbial community analysis revealed that after aeration rate redistribution, the relative abundances of Pseudomonadota, Bacteroidota, and Bacillota in the pre-reaction zone of MCFCASS were 39.17%, 17.78%, and 10.33%, respectively. In addition, the abundances of some functional bacterial groups in the first and fourth compartments of the main reaction zone shifted adaptively in response to the aeration rate redistribution, consistent with the trends in pollutant removal contributions in these compartments. Hierarchical clustering and principal coordinate analysis (PCoA) further indicated that aeration rate redistribution influenced the microbial community structure. The above laboratory-scale optimization results may provide a preliminary reference for aeration control and improvement of denitrification performance in similar processes. Full article

Currently, the escalating global problem of soil salinization severely limits the yield and quality of processing tomatoes. However, the differential responses and salt-tolerance strategies among processing tomato genotypes with different salt tolerances under salt stress remain largely elusive. Therefore, this study used salt-tolerant genotype ‘S39’ and salt-sensitive genotype ‘S37’ as materials. Seeds were sown in plug trays, and seedlings at the two-leaf-one-heart stage were transplanted into hydroponic containers filled with Hoagland nutrient solution. When seedlings reached the four-leaf-one-heart stage, they were exposed to NaCl treatments of 0 mM (control), 120 mM (Na120), and 180 mM (Na180). Plant samples were collected at 3, 6, and 9 days after treatment to determine growth parameters, physiological indices, and gene expression levels, aiming to reveal the dynamic differential responses to salt stress between the two processing tomato genotypes. The results demonstrated that the inhibitory effect of NaCl on the growth of processing tomatoes was aggravated with increasing NaCl concentration and treatment duration. The most significant difference in salt tolerance between the two genotypes was observed at 9 days under 180 mM NaCl treatment. At this sampling point, the relative salt-stress indices of superoxide dismutase (SOD) activity, peroxidase (POD) activity, soluble sugar content, proline content, chlorophyll a, chlorophyll b, and total chlorophyll (a + b) in ‘S39’ were significantly higher than those in ‘S37’ by 31.55%, 53.40%, 66.70%, 65.07%, 20.80%, 15.74%, and 19.44%, respectively. In addition, Na contents in roots and stems, as well as K contents in stems and leaves, were significantly higher in ‘S39’ than in ‘S37’ by 43.40%, 8.67%, 22.08%, and 21.99%, respectively. In contrast, relative electrolyte leakage and malondialdehyde (MDA) content in ‘S37’ were 15.54% and 12.44% higher than those in ‘S39’. In addition, photosynthetic parameters, including net photosynthetic rate (A_net), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), transpiration rate (E), and chlorophyll fluorescence parameters, were more stable in ‘S39’ than in ‘S37’. In conclusion, ‘S39’ possesses stronger salt tolerance via a multi-level regulatory strategy involving an enhanced antioxidant enzyme system, elevated accumulation of osmoregulatory substances, improved mineral ion balance, and increased stability of the photosynthetic apparatus. This study provides a comprehensive multi-level analysis of the differential salt tolerance mechanisms in processing tomato genotypes with contrasting salt tolerances and lays a theoretical basis for the screening and identification of salt-tolerant germplasm in processing tomatoes. Full article

Plant extracts are widely used as natural pesticides, cosmetic ingredients, and in pharmaceutical applications. However, their poor water solubility and stability limit their usability. Lipid nanoparticles (LNPs) offer an effective encapsulation strategy to overcome these challenges. This study demonstrates the encapsulation of three representative substances from these industries: quercetin as a pesticide, irones as a cosmetic ingredient, and nucleic acids for pharmaceutical use. Ultrasonic treatment was used for the encapsulation of quercetin and irones, and a concept for continuous encapsulation in a plug flow reactor was proposed for process intensification. Inline multi-angle light scattering and dynamic light scattering measurements proved effective for real-time monitoring and enabled the replacement of traditional batch measurements. In the pharmaceutical area, mRNA-based therapies require LNP encapsulation to prevent nucleic acid degradation. Plant-based β-sitosterol was used as an alternative helper lipid to cholesterol, resulting in an average particle diameter of 72 nm and an encapsulation efficiency of 91%, comparable to commercial formulations such as the Comirnaty vaccine. Furthermore, a novel process model based on population balances was developed to simulate the entire manufacturing process, from rapid mixing in a T-mixer to particle stabilization via buffer exchange during diafiltration. By applying a quantitative and distinctive model validation workflow, the model was shown to be as accurate and precise as the experimental data, enabling its use as a digital twin for autonomous continuous operation. In summary, this study contributes to reducing the facility footprint and cost of goods through the implementation of continuous processing and model-based control. This approach improves productivity by 20% and reduces process time by a factor of two. Full article

The steam generator is a core component of nuclear power plants that facilitates heat exchange between the primary and secondary circuits, directly impacting the overall operation of the plant in terms of safety and reliability. During prolonged operation, the heat transfer tubes of the steam generator are subjected to erosion, corrosion, and cracking due to high-temperature, high-pressure fluid impact and vibration. Existing in-service inspection strategies for heat transfer tubes generally employ fixed intervals and coverage, failing to effectively differentiate the actual risk of tubes in various regions, leading to wasted inspection resources or safety hazards. This paper proposes a dynamic inspection and plugging management strategy based on flow-induced vibration (FIV) analysis, specifically utilizing the flow stability ratio (FSR). By calculating the FSR of heat transfer tubes, the strategy categorizes them into high-risk, medium-risk, and low-risk regions, and dynamically adjusts inspection frequency and coverage based on these risk levels. Theoretical analysis and validation with actual data demonstrate that this strategy can improve inspection efficiency and ensure the safety of the steam generator. Full article

Automated fruit harvesting is crucial for alleviating labor shortages and enhancing agricultural productivity. In this context, it is crucial to obtain information on fruit poses before picking in order to avoid damaging the fruit and/or the plant. However, the complex and unstructured orchard environment poses significant challenges regarding the pose estimation task. In this study, a dragon fruit pose estimation (DFPE) framework using a single RGB image is proposed for dragon fruit automated harvesting, which includes three key components: dataset annotation processing, keypoint detection, and geometric pose estimation. First, a multi-source dataset consisting of 8467 images is constructed to enhance the estimation model’s generalizability. A pseudo four-keypoint annotation strategy is designed to fit the annotation rules of mainstream single-class keypoint detection models and mitigate the inherent limitations of multi-target keypoint detection in agricultural scenarios. This strategy implicitly encodes the fruit’s orientation using bounding box group IDs, while preserving geometric information for pose inference. Then, the fruit body and its two core keypoints (navel and stem) are detected via a real-time keypoint detection model. Notably, the proposed DFPE framework is detector-agnostic: other mainstream keypoint detection models can also be plugged into the subsequent geometric pose inference stage, which guarantees the generality and scalability of the framework. Finally, a dragon fruit pose estimation algorithm based on customized geometric constraints is designed, which takes the detected pose information as the input and outputs the posture of dragon fruit. The results of experiments conducted in natural orchard and laboratory environments demonstrate that the ellipses fitted using the proposed DFPE framework closely aligned with fruit contours, even under foliage occlusion conditions. In the laboratory environment, roll errors reached a maximum of 14.8°, whereas yaw errors peaked at 13.4°. Crucially, all roll and yaw errors remained consistently below 15°, which is well within the tolerance threshold required for non-destructive picking operations using a harvesting robot. In summary, this work presents a low-cost solution for dragon fruit pose estimation from a single RGB image, which can potentially be extended to other ellipsoid crops and is suitable for implementation in harvesting robots operating in orchards. Full article

This study presents a fully integrated process for the flexible conversion of biogenic waste into synthetic natural gas (bio-SNG) and electricity centred on a 100 kWth dual concentric bubbling fluidised bed steam gasifier. The raw syngas is processed in a high-temperature gas cleaning section, and the resulting clean, H₂-rich syngas is directed to three alternative downstream configurations: (i) conventional methanation, (ii) enhanced methanation with external H₂ supplied by a reversible solid oxide cell (rSOC), and (iii) electricity generation via the same rSOC operating in fuel cell mode. The overall process is modelled in Aspen Plus, in which the gasification section is constrained by experimentally derived syngas data, while downstream units are described through thermodynamic and kinetics-based models. Methanation is simulated using a plug-flow reactor model based on validated kinetic expressions, while the rSOC operating in electrolysis and fuel cell mode is modelled using performance parameters of commercial stacks. A plant-wide heat integration strategy based on composite curve analysis is implemented to maximise internal heat recovery and minimise external utilities. The enhanced methanation configuration enables the production of bio-SNG with high methane content (up to 93.3 vol.% dry, N₂-free), with a yield 0.72 kg/kg_Biomass and a fuel efficiency of 70.1%. In electricity production mode, the system reaches an electrical efficiency of 43.1% with complete elimination of auxiliary fuel through thermal integration. These results demonstrate the capability of a single integrated plant to flexibly switch between fuel synthesis and power generation, enhancing adaptability to fluctuating electricity and methane market conditions while maintaining high efficiency. Full article

Sechium edule (Cucurbitaceae), commonly known as chayote, which is a cucurbit of economic relevance, has experienced higher incidence of wilting from Phytophthora capsici in Mexican commercial fields during heavy rainfall. The infection process of this oomycete on chayote stems at the anatomical level had not been documented. This study characterized histological changes in chayote stems infected with P. capsici. Plants were inoculated at the stem base with P. capsici mycelial plugs, while controls received sterile plugs. Stem samples collected at 8, 12, 16, 22, and 30 days post-inoculation were processed and stained using safranin O–fast green. Microscopic observations showed progressive anatomical alterations. At 8 dpi, hyphae appeared in cortical parenchyma and epidermis, with phenolic compound accumulation. By 12 dpi, stromata and sporangia were visible in vascular and cortical tissues, with tyloses formation. At 16 dpi, cell wall collapse and xylem colonization became evident. These effects intensified at 22 and 30 dpi, with tissue degradation and an abundance of hyphae. Control stems maintained intact structures. Macroscopically, plants remained asymptomatic until 12 dpi, when brown lesions appeared. By 22 dpi, leaf yellowing and stem necrosis were observed, leading to plant death by 30 dpi. The results demonstrate the rapid colonization of chayote tissues by P. capsici, and its impact on vascular integrity. This study provides knowledge for future research on host resistance and disease management in chayote crops. Full article

Water availability represents a major limiting factor for crop production, particularly in Mediterranean agroecosystems. In parallel, water-stressed plants are often more susceptible to diseases, including Grapevine Trunk Diseases (GTDs), such as Botryosphaeria Dieback caused by Botryosphaeriaceae species. In Italy, the increasing prevalence of GTDs in young table grape plants and nursery material highlights the need to better understand the interaction between abiotic stress and pathogen dissemination in woody tissues. This study investigated the relationship between different water regimes (WRs) and infections by Neofusicoccum parvum. Grapevine cuttings (Vitis vinifera ‘Italia’ vines grafted onto the rootstock ‘140 Ruggeri’) were subjected to three WRs (20%, 50%, and 100% of crop evapotranspiration, ET_c) under controlled environmental conditions and, subsequently, inoculated with mycelial plugs of N. parvum at both the scion and rootstock levels. Plant responses were monitored non-destructively using low-cost proximal sensing tools, including leaf temperature (T_leaf) and the Normalized Difference Vegetation Index (NDVI). Disease development was assessed by measuring internal necrotic lesion extension. Reduced irrigation was associated with increased disease severity, while proximal sensing detected differences in plant physiological responses among water regimes. Overall, the results highlight the interplay between water availability, plant physiological status, and disease severity under controlled conditions. Full article

Strawberry (Fragaria × ananassa Duch.) propagation has evolved significantly over the past 20 years, transitioning from traditional field nursery systems to advanced, controlled, environment production. This review synthesizes recent advances in propagation methods, environmental regulation, and disease management strategies. Traditional field systems face mounting challenges from soilborne pathogens (Neopestalotiopsis species, Phytophthora cactorum, Verticillium dahliae) and regulatory restrictions on methyl bromide fumigation. Plug plant technology offers 80–95% disease reduction and 3–7-week production cycles versus 12–16-weeks traditional cycles, although at higher unit costs. Advanced tray plant systems developed in the Netherlands enable 10–11 months cold storage and programmed year-round production schedules. Elevated bench propagation systems have emerged as dominant commercial technology in East Asian regions, particularly Korea and Japan, where disease pressure necessitated alternatives to conventional nurseries. Micropropagation via temporary immersion bioreactors achieves 50–100% higher multiplication rates, while ensuring virus-free status. Environmental control research reveals complex photoperiod–temperature-chilling interactions regulating dormancy and flowering. Emerging technologies include F₁ hybrid seed propagation and AI-driven automation, achieving 15–25% energy efficiency gains. Despite progress, challenges remain in cost optimization, climate adaptation, and region-specific protocols. This review provides a comparative framework for nursery system selection under evolving climatic and regulatory constraints, identifying critical knowledge gaps and future research priorities for sustainable strawberry propagation. Full article

To address the issues of a low single-seed qualification index and a high missed-seeding index in the process of leafy vegetable plug seedling sowing, this study proposes a lightweight seeding performance detection model named VS-YOLO based on YOLO11n. The model is then deployed on the edge device, the NVIDIA Jetson Xavier NX. A concise and intuitive graphical user interface (GUI) was developed and an automated detection system for vegetable seeding performance was constructed. Based on the empty cells identified by the system, a real-time data transmission mechanism between the Jetson device and a PLC-based control unit is established, enabling the intelligent reseeding device to perform precise reseeding at the designated cell location, achieving row-wise and cell-specific intelligent planting. VS-YOLO incorporates several innovative improvements, including the introduction of a Context Anchor Attention (CAA) module to form the C2PSA_CAA module, the adoption of the Wise Intersection over Union version 3 (WIoU v3) loss function, and the addition of an extra-small object detection head. These enhancements significantly improve the classification and recognition capability for small-sized vegetable seeds while notably reducing the number of model parameters. Experimental results show that VS-YOLO achieves a mAP@0.5 of 96.5% and an F1 Score of 93.45% in detecting the seeding performance of three types of vegetable seeds, outperforming YOLO11n’s 91.5% and 85.19% by 5.0% and 8.26%. The parameter count of VS-YOLO is only 1.61 M, which is 37.6% lower than YOLO11n’s 2.58 M, making it lightweight. Operating at a productivity rate of 120 trays per hour, the system achieved an accuracy of 99.03%, 89.83%, and 92.26% for single-seed prediction, multiple-seeding prediction, and missed-seeding prediction. The single-seed qualification index and missed-seeding index were 93.43% and 4.68%. After reseeding, these indices improved to 97.61% and 0.32%, representing an increase of 4.18% in the single-seed qualification index and a decrease of 4.36% in the missed-seeding index. The significant enhancement offers new ideas and technical approaches for the advancement of seeding performance detection and reseeding systems for vegetable plug seedling production. Full article

Cornus officinalis is a valuable traditional Chinese medicinal (TCM) plant species with both therapeutic and ornamental attributes. It is widely used in TCM prescriptions to nourish the liver and kidneys and constitutes a critical component of numerous classical formulas. In recent years, the large-scale cultivation of this medicinal plant has been expanded in Xixia County, Henan Province, China. Field investigations have revealed widespread brown leaf spot, accompanied by reductions in yield and quality. In this study, symptomatic leaves were collected for pathogen isolation. Tissue isolations consistently yielded a Colletotrichum fungus, and morphology combined with multi-locus phylogenetic analyses (the internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase, chitin synthase, actin, and β-tubulin) identified the pathogen as Colletotrichum siamense. Pathogenicity assays (conducted by either wounding and inoculating detached leaves with a mycelium plug or spraying a conidium suspension on healthy potted plants) reproduced field symptoms, and the pathogen was re-isolated, thereby fulfilling Koch’s postulates. In vitro fungicide assays showed that carbendazim, tebuconazole, and prochloraz were highly effective against the pathogen, providing preliminary information for chemical management. This is the first documentation of C. siamense causing leaf anthracnose on C. officinalis and provides a basis for developing targeted control strategies to mitigate disease impacts and preserve yield and quality. Full article

Chlorine contact tanks are crucial for wastewater disinfection, with performance strongly influenced by internal hydraulic characteristics. This study applies Computational Fluid Dynamics (CFD) to analyze and improve the hydraulics of the chlorination contact tank in a Wastewater Treatment Plant in the Southern Italy. A three-dimensional transient CFD model was developed using the Reynolds-Averaged Navier–Stokes (RANS) equations with the Renormalized Group (RNG) turbulence closure. The model simulated flow patterns, tracer transport, and chlorine decay kinetics under the existing configuration and two alternative configurations. Conservative tracer pulse simulations enabled the calculation of Residence Time Distributions (RTDs) and hydraulic efficiency indicators, including the Baffling Factor (θ₁₀), Morrill index (Mo), and Aral–Demirel index (AD). A typical contact tanks geometry exhibits specific hydraulic characteristics, including recirculation behind baffles and stagnant zones in sharp corners, which inevitably affects the contact time. The first alternative, namely featuring rounded corners, moderately reduced dead zones, but did not substantially mitigate recirculation. The second alternative, herein called combining rounded corners with perforated baffle walls, substantially improved hydraulic performance, yielding flow patterns closer to plug-flow. RTD peaks were higher and narrower for the modified designs, and hydraulic indices improved, with Mo decreasing by approximately 5%. These hydraulic enhancements are expected to increase disinfection efficiency by providing more uniform chlorine exposure. The results demonstrate that geometric modifications effectively optimize contact tank hydraulics and highlight the role of CFD as a design and retrofit tool for water and wastewater disinfection systems. Full article

To improve the mechanized transplanting efficiency for large-scale broccoli production in Ningxia, this study aims to identify key morphological traits of seedlings suitable for mechanized transplanting. A Box–Behnken design was used to set three experimental factors, broccoli variety, seedling age, and plug tray specification, to evaluate their effects on seedling plant type (plant height, stem diameter, canopy diameter, stem inclination angle, and plant type cone angle) and root system characteristics (substrate loss rate). The results showed that plug tray specification was the primary factor affecting substrate loss rate, followed by variety and seedling age. Seedling age was the dominant factor affecting plant height, stem diameter, and canopy diameter, while plug tray specification primarily influenced stem inclination angle. Optimization via response surface methodology (RSM) indicated that the best transplanting performance was achieved with the “Hannai Youxiu” variety (excellent cold tolerance), 30-day-old seedlings, and 72-cell or 98-cell plug trays. Field validation confirmed that under these optimal parameters the mechanized transplanting feeding rate reached 100%, the seedling missing rate was 2.5%, and the transplanting qualification rate was 97.5%, with all RMSE values being less than 7.5%. These findings provide a scientific basis for the mechanized transplanting of broccoli in Ningxia, recommending the “Hannai Youxiu” variety and 98-cell plug trays with 30-day-old seedlings to enhance transplanting quality and production efficiency. Full article

New intensified flotation technologies have emerged to enhance fine and ultrafine particle recovery. However, their modelling remains challenging, as it requires defining the effective collection volume, residence time, and internal recirculation, factors not included in conventional models, while also facing operational complexity and the limited availability of key hydrodynamic and kinetic data. This study presents the development of a flotation model for the Concorde Cell technology, which separates the flotation process into three stages: collection zone, separation tank, and froth transport. The collection zone was represented as a plug-flow reactor with a rectangular rate of constant distribution; the separation zone as a perfect mixer with a detachment efficiency factor; and the froth recovery as a function of froth stability, residence time, and transport distance. Water recovery and gangue entrainment were also modelled to estimate concentrate grades. The model was tested and calibrated using experimental results from tests conducted in a Concorde Cell Lab Unit. A case example is presented for a semi-batch exhausting test performed with minerals from a copper concentrator plant. Good agreement between simulated and experimental results demonstrated the robustness and flexibility of the model. Additionally, the results showed collection rate constants significantly higher than those typically reported for conventional flotation cells (more than 100 times higher for Cu), due to the smaller collection volume and shorter residence time in the Concorde Cell. The calibrated model was then applied to simulate an industrial operation, where sensitivity analyses showed consistent responses to variations in operating conditions. Overall, the proposed model provides a practical tool for predicting the metallurgical performance of intensified flotation cells, supporting the integration of this new technology into modern concentrator flowsheets for the development of hybrid circuits. Full article

Labor shortages and reliance on manual seedling transplanting constrain pepper production from meeting market demand. To address this mechanization gap, the development of new agricultural machinery is an urgent priority. This study presented kinematic modeling and field validation of an automatic link-driven hopper planting unit for a 3.4 kW walking-type pepper transplanter under development. Kinematic behavior of the hopper was analyzed through mathematical modeling and dynamic simulation and validated under actual transplanting conditions under ridge-patterned field. The optimal design (crank length: 75 mm; 60 rpm) achieved a stable elliptical trajectory that enabled synchronized seedling pickup, tray release, and soil deposition while maintaining vertical alignment. Under this setup, the hopper followed a stable elliptical trajectory (166.88 mm × 318.81 mm), with supply and deposition coordinates of approximately (321 mm, −322 mm) and (293 mm, −617 mm), and peak velocities and accelerations within 0.47 m/s and 1.68 m/s², respectively. Field results showed that the proposed mechanism enabled reliable transplanting performance, achieving a mean planting depth of 27.06 ± 8.18 mm and an uprightness angle of 80.03 ± 7.56°, which fall within agronomic requirements for early pepper establishment. The overall defect rate was low (7.17 ± 3.73%), leading to a 92.83 ± 3.73% success rate at a throughput of 24 seedlings min⁻¹. Variety-dependent responses were observed: Kaltan seedlings exhibited lower defect rates and greater stability than Shinhung seedlings, highlighting the importance of plug strength and stem rigidity in automated systems. These results demonstrate that the mechanism supports fully automated transplanting with acceptable agronomic quality and provides practical design guidance for advancing mechanized pepper production. Full article