Search Results (1,324)

Auxiliary frequency modulation (FM) for coal-fired units has been recognized as a promising approach through multiple batteries, which is due to their rapid charging and discharging characteristics. However, long-period engineering application needs continuous optimization of operational strategies to resist the decay characteristics of the battery, which greatly increases the difficulty of promotion. Hence, two replacement strategies of the battery were first proposed in this work, and they are characterized by simple operation. To test their feasibility, a lead–acid battery was selected as one study example, and the corresponding relationship between the duration day and the replacement scheme was emphatically analyzed, according to the AGC instruction and the self-adjustment capacity of coal-fired units. Results showed that the replacement capacity of the battery is nearly linear in the duration day, while the difference from the discharge depth is negligible in this study. In addition, the capacity ratio of 1.3 to 5 is considered to have the best application potential because of the same duration days between old and new batteries. The commutative replacement can immortally extend the duration day, and obviously, the replacement process of old and new batteries always maintains that two battery groups work. Conclusively, the case analysis for two replacement strategies showed that they deeply lowered the initial capacity of the battery, which can reduce the investment costs. In a word, two replacement strategies for the battery proposed in this study provide a reference for the economic evaluation and optimization of battery use for auxiliary FM. Full article

Objectives: miR-21-5p, miR-145-5p and miR-382-5p have been associated with angiogenesis, which plays a central role in tumor growth and metastasis formation. The aim of the study was to determine whether expression of these three potentially angiogenic miRNAs is related to the lymphatic spread capability of gastric adenocarcinoma and patient survival. Methods: Pathoclinical data of 123 patients who underwent elective gastric resection for adenocarcinoma between 1 August 2006 and 31 December 2013 were retrospectively retrieved. The major concerns were the total number of lymph nodes retrieved, the number of positive nodes, depth of the tumor invasion to the stomach wall, pTNM stage of the disease, Lauren histological tumor type, presence of a mucinous component in the cancer tissue, tumor location in the stomach and survival outcome. The cancer tissues of patients were examined for the expression levels of miR-21-5p, miR-145-5p and miR-382-5p. Results: Elevated hsa-miR-21-5p expression levels and downregulated hsa-miR-145-5p levels were observed in patients with a higher pT stage, lymph node metastasis and advanced pTNM stage. Additionally, hsa-miR-145-5p expression was lower in patients with cardia involvement and a Lauren intestinal-type carcinoma. hsa-miR-382-5p levels were higher in patients with non-mucinous gastric carcinoma. Both hsa-miR-145-5p and hsa-miR-21-5p were predictors of the presence of node metastasis, even when adjusted for pT status. hsa-miR-145-5p was significantly associated with improved survival. hsa-miR-145-5p was significantly associated with an increased probability of surviving 3 years, while increased hsa-miR-21 expression was significantly associated with reduced 3-year survival. All these associations were confirmed in multivariate models, which also included pT and M staging. Conclusions: The upregulation of miR-21-5p and downregulation of miR-145-5p are independent prognostic factors for lymph node metastasis and could serve as specific biomarkers of the lymphatic spread of gastric adenocarcinoma. miR-145-5p downregulation is an independent prognostic factor for overall survival. Full article

This study investigates the primary frequency regulation dynamic characteristics of industrial steam extraction turbine units under deep peak regulation conditions. A high-fidelity integrated dynamic model was established, incorporating the governor system, steam turbine with extraction modules, and interconnected pipeline dynamics. Through comparative simulations and experimental validation, the model demonstrates high accuracy in replicating real-unit responses to frequency disturbances. For the power grid system in this study, the frequency disturbance mainly comes from three aspects: first, the power imbalance formed by the random mutation of the load side and the intermittence of new energy power generation; second, transformation of the energy structure directly reduces the available frequency modulation resources; third, the system-equivalent inertia collapse effect caused by the integration of high permeability new energy; the rotational inertia provided by the traditional synchronous unit is significantly reduced. In the cogeneration unit and its control system in Guangxi involved in this article, key findings reveal that increased peak regulation depth (30~50% rated power) exacerbates nonlinear fluctuations. This is due to boiler combustion stability thresholds and steam pressure variations. Key parameters—dead band, power limit, and droop coefficient—have coupled effects on performance. Specifically, too much dead band (>0.10 Hz) reduces sensitivity; likewise, too high a power limit (>4.44%) leads to overshoot and slow recovery. The robustness of parameter configurations is further validated under source-load random-intermittent coupling disturbances, highlighting enhanced anti-interference capability. By constructing a coordinated control model of primary frequency modulation, the regulation strategy of boiler and steam turbine linkage is studied, and the optimization interval of frequency modulation dead zone, adjustment coefficient, and frequency modulation limit parameters are quantified. Based on the sensitivity theory, the dynamic influence mechanism of the key control parameters in the main module is analyzed, and the degree of influence of each parameter on the frequency modulation performance is clarified. This research provides theoretical guidance for optimizing frequency regulation strategies in coal-fired units integrated with renewable energy systems. Full article

Reliable navigation for mobile robots in dynamic, human-populated environments remains a significant challenge, as moving objects often cause localization drift and map corruption. While Simultaneous Localization and Mapping (SLAM) techniques excel in static settings, issues like keyframe redundancy and optimization inefficiencies further hinder their practical deployment on robotic platforms. To address these challenges, we propose DKB-SLAM, a real-time RGB-D visual SLAM system specifically designed to enhance robotic autonomy in complex dynamic scenes. DKB-SLAM integrates optical flow with Gaussian-based depth distribution analysis within YOLO detection frames to efficiently filter dynamic points, crucial for maintaining accurate pose estimates for the robot. An adaptive keyframe selection strategy balances map density and information integrity using a sliding window, considering the robot’s motion dynamics through parallax, visibility, and matching quality. Furthermore, a heterogeneously weighted local bundle adjustment (BA) method leverages map point geometry, assigning higher weights to stable edge points to refine the robot’s trajectory. Evaluations on the TUM RGB-D benchmark and, crucially, on a mobile robot platform in real-world dynamic scenarios, demonstrate that DKB-SLAM outperforms state-of-the-art methods, providing a robust and efficient solution for high-precision robot localization and mapping in dynamic environments. Full article

Environmental protection tax is levied based on various types of emitted pollutants and has a significant impact on the green behaviors and ESG (environmental, social, and corporate governance) performance of enterprises. This article explores the green effect and the impact of environmental protection tax on the green behavior of listed companies with in-depth empirical analysis based on the data of industrial enterprises listed on the A-shares from 2018 to 2022 in China. Research has found that the implementation of environmental protection tax has played a significant driving role in improving the overall performance level of corporate ESG, and this tax system has formed a driving force mechanism for enterprises to increase investment in green innovation and effectively improve their comprehensive ESG performance. Green innovation plays a significant intermediary role between environmental protection tax and corporate ESG performance. It is suggested that regions should adjust the applicable amount of environmental protection tax, increase green innovation, and standardize pollution control and emission reduction regulations. Full article

Hybrid underwater gliders (HUGs) combine buoyancy-driven gliding with propeller-assisted propulsion, offering extended endurance and enhanced mobility for complex underwater missions. However, precise depth control remains challenging due to system uncertainties, environmental disturbances, and inadequate adaptability of conventional control methods. This study proposes a novel optimized line-of-sight active disturbance rejection control (OLOS-ADRC) strategy for HUG depth tracking in the vertical plane. First, an Optimized Line-of-Sight (OLOS) guidance dynamically adjusts the look-ahead distance based on real-time cross-track error and velocity, mitigating error accumulation during path following. Second, a Tangent Sigmoid-based Tracking Differentiator (TSTD) enhances the disturbance estimation capability of the Extended State Observer (ESO) within the Active Disturbance Rejection Control (ADRC) framework, improving robustness against unmodeled dynamics and ocean currents. As a critical step before costly sea trials, this study establishes a high-fidelity simulation environment to validate the proposed method. The comparative experiments under gliding and hybrid propulsion modes demonstrated that OLOS-ADRC has significant advantages: the root mean square error (RMSE) for depth tracking was reduced by 83% compared to traditional ADRC, the root mean square error for pitch angle was decreased by 32%, and the stabilization time was shortened by 14%. This method effectively handles ocean current interference through real-time disturbance compensation, providing a reliable solution for high-precision HUG motion control. The simulation results provide a convincing foundation for future field validation in oceanic environments. Despite these improvements, the study is limited to vertical plane control and simulations; future work will involve full ocean trials and 3D path tracking. Full article

This paper surveys the application of machine learning in fiber composite manufacturing, highlighting its role in adaptive process control, defect detection, and real-time quality assurance. First, the need for ML in composite processing is highlighted, followed by a review of data-driven approaches—including predictive modeling, sensor fusion, and adaptive control—that address material heterogeneity and process variability. An in-depth analysis examines six case studies, among which are XPBD-based surrogates for RL-driven robotic draping, hyperspectral imaging (HSI) with U-Net segmentation for adhesion prediction, and CNN-driven surrogate optimization for variable-geometry forming. Building on these insights, a hybrid AI model architecture is proposed for natural-fiber composites, integrating a physics-informed GNN surrogate, a 3D Spectral-UNet for defect segmentation, and a cross-attention controller for closed-loop parameter adjustment. Validation on synthetic data—including visualizations of HSI segmentation, graph topologies, and controller action weights—demonstrates end-to-end operability. The discussion addresses interpretability, domain randomization, and sim-to-real transfer and highlights emerging trends such as physics-informed neural networks and digital twins. This paper concludes by outlining future challenges in small-data regimes and industrial scalability, thereby providing a comprehensive roadmap for ML-enabled composite manufacturing. Full article

Water scarcity, soil salinization, and desertification threaten sustainable agricultural ecosystems of Hetao irrigation district, Yellow River Basin (YRB). Precise quantification of soil water dynamics and plant water consumption processes is essential for the agricultural sustainability of the irrigation district. Therefore, this study mainly focused on the crop coefficients and water consumption processes of three representative plant types in the Hetao irrigation district, each corresponding to a specific land system: Helianthus annuus (cultivated land), Tamarix chinensis (wasteland), and Phragmites australis (lake). The SIMDualKc model was calibrated and validated based on situ observation data (soil water content and yield) during 2018 (conventional conditions), 2023 and 2024 (deep water-saving conditions). Results show strong agreement between simulated and observed soil moisture and crop yields. The results indicate that the process curves of K_cb (basal crop coefficient) and K_cbadj (adjusted crop coefficient) nearly overlapped for the three plant types in 2018 and 2023. However, under the deep water-saving project implemented in 2024, the K_cbadj process curves for all three plant types exhibited a significant reduction (approximately 15%). Soil evaporation fractions (E/ET_cadj) were stable at 19–30% during the 2018, 2023, and 2024. The contribution of capillary rise to ET reached 38.61–43.18% in cultivated land (Helianthus annuus), 41.52–48.93% in wasteland (Tamarix chinensis), and 38.08–46.57% in lake boundary areas (Phragmites australis), which underscores the significant role of groundwater recharge in sustaining plant water consumption. Actual-to-potential transpiration ratios (T_a/T_p) during 2023–2024 decreased by 3–11% for Helianthus annuus, 5–12% for Tamarix chinensis, and 23% for Phragmites australis compared to T_a/T_p values in 2018. Capillary rise decreased approximately 10% during the whole system. Deep water-saving practices increased the groundwater depth and restricted groundwater recharge to plants via capillary rise, thereby impairing plant transpiration and growth. These findings provide scientific support for sustainable agriculture and ecological security in the Yellow River Basin. Full article

Background: Orthodontic auxiliaries can create plaque-retentive niches that inflame adjacent soft tissues. We compared bacterial colonization on molar bands, Nance buttons, and acrylic plates and assessed associated periodontal and palatal tissue responses in adolescents. Methods: In a cross-sectional study (n = 128; 10–17 years), clinical indices (Plaque Index, Gingival Index, bleeding on probing, probing depth) were recorded at device-influenced teeth. Palatal fibromucosa under palate-contacting devices was graded 0–3 (0 = none, 1 = mild/diffuse, 2 = moderate/confluent, 3 = marked with papillary hyperemia). Swabs from device surfaces, adjacent enamel, and palatal mucosa were cultured for total aerobic counts (log₁₀ CFU/cm²); Streptococcus mutans burden was quantified by qPCR (log₁₀ copies/mL). Group differences and adjusted associations were analyzed. Results: Palate-contacting devices harbored greater palatal biofilm and presented higher soft-tissue inflammation than bands. In adjusted models, device type (Nance, acrylic) remained associated with higher Gingival Index independent of measured behaviors and wear duration. Palatal colonization tracked closely with palatal erythema, supporting a local dose–response at the palatal interface. Conclusions: Appliance design is associated with distinct colonization patterns and soft-tissue responses; palate-covering acrylic components warrant device-specific hygiene and routine palatal inspection. Selecting designs with better cleansability and reinforcing plate-specific cleaning may mitigate palatal inflammation during treatment. Full article

Accurate detection of road surface information is crucial for enhancing vehicle driving safety and ride comfort. To overcome the limitation that traditional suspension systems struggle to respond to road excitations in real time due to time delays in signal acquisition and control, suspension preview control technology has attracted significant attention for its proactive adjustment capability, with efficient road surface information perception being a critical prerequisite for its implementation. This paper systematically reviews road surface information detection technologies for suspension preview, focusing on the identification of potholes and speed bumps. Firstly, it summarizes relevant publicly available datasets. Secondly, it sorts out mainstream detection methods, including traditional dynamic methods, 2D image processing, 3D point cloud analysis, machine/deep learning methods, and multi-sensor fusion methods, while comparing their applicable scenarios and evaluation metrics. Furthermore, it emphasizes the core role of elevation information (e.g., pothole depth, speed bump height) in suspension preview control and summarizes elevation reconstruction technologies based on LiDAR, stereo vision, and multi-modal fusion. Finally, it prospects future research directions such as optimizing robustness, improving real-time performance, and reducing labeling costs. This review provides technical references for enhancing the accuracy of road surface information detection and the control efficiency of suspension preview systems, and it is of great significance for promoting the development of intelligent chassis. Full article

We reconstructed the morphology of holes using silicone replication technology, and inverted the hole parameters to reveal the law of high-pressure water jet (HPWJ) hole formation under multi-field coupling. The results show that under the multi-field coupling effects, the evolution of the hole exhibits stage-wise characteristics; in the rapid expansion phase, the hole extends rapidly and deeply, forming a “wedge” pattern, and in the stabilization adjustment phase, the rate of hole expansion slows down, and the hole morphology shifts towards an “elliptical” or “teardrop-shaped” form. However, an increase in confining pressure inhibits the transformation of the hole morphology, and as a result, the “wedge-shaped” characteristics of the hole become more pronounced. With constant confining pressure, increased jet pressure significantly enhances both hole depth and volumetric average extension rate, exhibiting a positive correlation. Conversely, with constant jet pressure, increased confining pressure significantly decreases both hole depth and volumetric average extension rate, exhibiting a negative correlation. Based on silicone replication technology, we established a mapping relationship between ‘pore morphology-jet flow and environmental parameters’ which can be used to evaluate the pressure relief and permeability enhancement effects in deep low-permeability coal seams. By optimizing jet parameters, we can expand the scope of pressure relief and permeability improvement in coal seams, thereby enhancing gas drainage efficiency. Full article

A fully automated, buoy-based deployment sensor system is being developed to acquire high-quality water column data, and requires a controller to accurately position an array of sensors at various depths. The sensor system will be potentially deployed under rough ocean conditions. Depth is measured by a pressure sensor and adjusted through a rotating drum powered by a stepper motor. The proposed controller uses a model predictive control algorithm, a type of optimal control that predicts system response to optimize control actions used to track a desired variable-depth, setpoint profile. The profile is calculated to ensure smooth motion of the system, preventing motor malfunction. A simplified system model was created and used to simulate an open-loop test and system response. Constraints were applied to the control actions to match the practical limitations of the stepper motor. The simulated results show successful tracking of both a shallow and deep profile. At this stage of testing, the effects of ocean currents are considered by using a simple disturbance that provides the effect of ocean currents. A practical prototype that can implement the model predictive controller was tested on the physical buoy-based system with good control performance. Full article

The rehabilitation of coal mine sites in semi-arid environments is a step in combating desertification. A promising rehabilitation approach involves the development of anthropic soils that can support vegetation. However, reliable soil quality indicators are needed to evaluate long-term sustainability of rehabilitation strategies. In a coal mine area in northeastern Spain, two anthropic soils (0.5 m thick) were constructed by layering fine-textured coal residues at the bottom, topped with coarse overburden materials. Chemical fertility was enhanced using combinations of semi-liquid manure (25 or 60 mm) and straw (0 or 15 Mg ha⁻¹), resulting in four treatments randomly distributed across both soil surfaces. Two abiotic indicators were selected for sustainability assessment: soil organic carbon (SOC) fractions and microstructure. Seven years after rehabilitation activities were completed, SOC fractions were analyzed. In addition, two years later, soil porosity and specific pore perimeter were also assessed in soil thin section images. The results indicated that the lower manure rate promoted more efficient SOC stabilization, evidenced by a 4–5-fold increase in specific pore perimeter at 0–5 cm depth, and lower fulvic acid content at 5–20 cm depth, compared with the higher manure rate. Micromorphological analysis proved to be a sensitive method for detecting early improvements in the physical quality of anthropic soils, highlighting the importance of adjusting manure rates for sustainable coal mine rehabilitation. Full article

Compared to shallow geothermal systems, coaxial medium-deep and deep borehole heat exchangers (MDBHE and DBHE) offer higher temperatures and heat extraction rates while requiring less surface area, making them attractive options for sustainable heat supply in combination with ground-source heat pumps (GSHP). However, existing simulation tools for such systems are often limited in computational efficiency or open-source availability. To address this gap, we propose a rapid modeling approach using the open-source Python package “pygfunction” (v2.3.0). Its workflow was adjusted to accept the fluid inlet temperature as input. The effective undisturbed ground temperature and ground thermophysical properties were weight-averaged considering stratified ground layers. Validation of the approach was conducted by comparing simulation results with 12 references, including established models and experimental data. The proposed method enables fast estimation of fluid temperatures and heat extraction rates for single boreholes and small-scale bore fields in both homogeneous and heterogeneous geological conditions at depths of 700–3000 m, thus supporting rapid assessments of the coefficient of performance (COP) of GSHP. The approach systematically underestimates fluid outlet temperatures by up to 2–3 °C, resulting in a maximum underestimation of COP of 4%. Under significant groundwater flow or extreme geothermal gradients, these errors may increase to 4 °C and 6%, respectively. Based on the available data, these discrepancies may result in errors in GSHP electric power estimation of approximately ±10%. The method offers practical value for GSHP performance evaluation, geothermal potential mapping, and district heating network planning, supporting geologists, engineers, planners, and decision-makers. Full article

Paddy cultivation in the black soil region of northeast China is faced with the problems of low irrigation water use efficiency (IWUE) and low temperature stress during sowing. Therefore, the combinations of film mulching and water-saving irrigation methods were adopted to adjust the balance between water and yield under the condition of suitable soil water and heat environment, and to quantify the relationship between irrigation water and yield formation. This study investigated the mechanisms of two kinds of biodegradable film mulching combined with two water-saving irrigation on soil hydrothermal conditions in cold-region paddy fields. The results show that film mulching improved the water retention capacity of the soil at different depths, with black film exhibiting better moisture conservation than white film. Overall, controlled irrigation resulted in higher soil moisture than ridge irrigation before the heading–flowering stage, but lower values in heading–flower stage and the later stage. Film mulching also increased soil temperature across different layers, with black film showing a more warming effect in the 0–5 cm soil layer. All combinations of biodegradable film mulching and water-saving irrigation enhanced the IWUE, with the ridge irrigation combined with black film mulching showing the most significant improvement. This research provides technical references for water-efficient rice cultivation in cold regions. Full article