Search Results (10,720)

Against the backdrop of increasing penetration of renewable energy sources such as wind and solar power, coupled with intermittent regional power restrictions, ensuring the quality of power transmission has become increasingly critical. The volatility and uncertainty of wind and photovoltaic output exacerbate dynamic fluctuations in net load on the grid side, necessitating hydroelectric units to undertake more frequent Automatic Generation Control (AGC) regulation tasks in complementary hydro–wind–solar operations. However, frequent regulation processes significantly intensify the operational stress on actuating mechanisms within the governor system, thereby accelerating wear and degradation of equipment such as hydraulic turbine servomotors. This study employs modeling and simulation to investigate the influence and mechanistic role of key control parameters in the AGC process on the wear of hydraulic turbine servomotors. Utilizing pulse count and pulse width metrics, a reasonable quantification of this impact is established. A multi-objective optimization framework for AGC parameters is constructed, and frontier solutions are selected based on quantified equipment wear values. Simulation results indicate that the optimized parameters achieve a balanced performance in terms of settling time, steady-state performance, and comprehensive dynamic metrics during power closed-loop transition processes. This approach effectively mitigates the actuation intensity of servomotors while satisfying regulation quality requirements, thereby enhancing the overall performance of the power closed-loop adjustment process. Full article

Synchronous transfer has been widely studied in public transport scheduling, with most research focusing on coordination among conventional bus lines. However, with the rapid expansion of urban rail transit systems, metro–bus transfers have become increasingly important for enhancing overall urban public transport network performance. This study investigates the maximum synchronous transfer problem between metro and conventional bus services under passenger flow constraints. Considering the large transfer demand and the pulse-arrival characteristics of metro trains, a passenger waiting constraint at bus stops is incorporated to reflect capacity limitations and crowding effects. A passenger-flow-constrained maximum synchronization model is formulated to optimize bus departure times without increasing service frequency. Dongjiekou Metro Station and three surrounding pairs of bus stops are selected as a case study. Model parameters are determined through field surveys and operational data. The Grey Wolf Optimizer (GWO) and a simulated annealing–improved Grey Wolf Optimizer (SA-IGWO) are employed to solve the proposed model. The results show that both algorithms significantly improve synchronized transfer volumes by adjusting departure times without increasing service frequency. Compared with the original schedule, the SA-GWO achieves an improvement in synchronization performance ranging from 45% to 50%, outperforming the standard GWO. Full article

This study investigated the effects of fermented Chinese chive (FCC) juice supplementation on growth performance, blood parameters, meat quality, and fresh meat volatile compounds in Small-Tailed Han sheep. Sixty sheep were randomly assigned to a control group (CG; basal diet) or an FCC juice treatment group (TG; basal diet supplemented with 1.0 mL/kg feed offered on an as-fed basis), with three pens per treatment and 10 sheep per pen. FCC juice significantly increased average weight gain (AWG) and average daily gain (ADG) (p < 0.05), whereas carcass traits were not significantly affected (p > 0.05). Most meat quality traits, antioxidant indices, and serum biochemical parameters were unchanged, although serum glucose (GLU) and cholesterol (CHO) decreased in the FCC juice treatment group (p < 0.05). GC × GC-TOF/MS analysis showed that FCC juice altered the volatile profile of fresh sheep meat. Compared with the control group, the FCC juice treatment group showed higher relative contents of aldehydes, ketones, and heterocyclic compounds, but lower contents of hydrocarbons and acids. Seventeen differential volatile compounds were identified using VIP > 1 and FDR-adjusted p < 0.05, with esters representing the major upregulated class. Based on the published odor descriptors of the identified volatile compounds, the FCC juice treatment group showed stronger green and apple-like aroma-associated characteristics. Overall, FCC juice showed a modest positive effect on growth performance and altered the volatile compound profile of fresh sheep meat; however, flavor-related findings should be regarded as preliminary because of the limited slaughter sample size and the absence of direct sensory validation. Full article

Non-diffracting beams play crucial roles in the field of free-space optical communication due to their robust resistance to distortion in atmospheric turbulence. As a non-diffracting beam characterized by multiple parameters, the Tricomi beam exhibits great versatility and adjustability, attracting considerable interest recently. In this paper, we study the propagation properties of Tricomi beam in atmospheric turbulence based on the theory of random phase screen. It is found that the performance of Tricomi beam in atmospheric turbulence shows strong dependence on its asymmetric constants, topological charge, and half-cone angle. Meanwhile, the Tricomi beam manifests superior resistance to distortion and spatial mode stability in contrast to the conventional non-diffracting Bessel beam. Our work provides a valuable theoretical foundation for the design and performance optimization of next-generation free-space optical communication systems, potentially enabling enhanced data transmission fidelity over long atmospheric paths. Full article

Background/Objectives: The autologous arteriovenous fistula (AVF) is the primary vascular access (VA) method for hemodialysis (HD), with superior patency and a lower complication rate than arteriovenous graft (AVG) or central venous catheter (CVC). The primary objective of this study is to analyze the impact of dialysis on the CVC at the time of AVF creation on its long-term primary patency. Methods: This retrospective, single-center, observational study included 248 patients admitted for AVF creation. Demographic characteristics, comorbid conditions, and laboratory parameters were retrieved from the hospital’s electronic medical records. The primary outcome of the study was long-term AVF failure, defined as the inability to perform hemodialysis through the newly created AVF. Results: A total of 132 (53.2%) were receiving dialysis via a CVC at the time of AVF creation. During a mean follow-up of 2.21 ± 1.54 years, 47 patients (18.95%) failed to achieve functional maturation at 6 weeks, and 81 patients (32.66%) developed long-term AVF failure. Demographic characteristics were similar between patients with and without CVC at AVF creation, with no significant differences in age (p = 0.358) or sex (p = 0.574). Comorbidities and risk factors were also similarly distributed, showing no significant variation. The types of AVF varied by CVC status, with fewer RC-AVF (p = 0.038) and more BC-AVF (p = 0.032) in patients with a CVC. Failure was significantly more frequent in patients with CVC use at the time of AVF creation than in those without CVC (p < 0.001). Kaplan–Meier analysis demonstrated lower long-term patency in patients dialyzed via CVC (p < 0.001). In Cox regression analysis, dialysis via CVC at AVF creation was associated with AVF failure (HR: 2.53, p < 0.001), and the association remained significant after full adjustment (HR: 3.13, p < 0.001). Female sex, active smoking, smaller arterial and venous diameters, and RC-AVF were additional risk factors associated with failure. Conclusions: Dialysis via a CVC at the time of AVF creation was associated with an increased risk of long-term AVF failure, even after full adjustment models. Full article

Background: Thyroid nodules are common, yet only a small proportion are malignant. The independent role of nodule size in malignancy risk remains debated, particularly after adjustment for clinical, biochemical, and sonographic features. Methods: A retrospective cohort study was conducted on adult patients with thyroid nodules evaluated between 2018 and 2025 at a tertiary care center. Clinical, laboratory, ultrasound, cytology, and histopathology data were extracted. Thyroid-stimulating hormone (TSH), free thyroxine (free T4), and sonographic characteristics were analyzed. Univariable and multivariable logistic regression were performed. Missing ultrasound data were addressed using multiple imputation (m = 20), with pooled estimates derived using Rubin’s rules. The final multivariable model included 446 patients. Results: A total of 446 patients were included, of whom 91 (20.4%) had thyroid malignancy. Malignant nodules were significantly larger than benign nodules (2.30 [1.80] cm vs. 1.80 [1.13] cm; p = 0.015). In univariable analysis, TSH, free T4, and multiple ultrasound features were associated with malignancy. In multivariable analysis, nodule size remained the strongest independent predictor of malignancy (adjusted odds ratio [aOR] 1.51; p < 0.001). Hypoechogenicity (aOR 2.07; p = 0.020) and microcalcifications (aOR 1.86; p = 0.047) also remained independently significant, whereas thyroid function parameters were not associated with malignancy after adjustment. Conclusions: Thyroid nodule size is the strongest independent predictor of malignancy, with select ultrasound features retaining additional predictive value. These findings support incorporating nodule size more prominently into thyroid cancer risk stratification while maintaining key sonographic features. Full article

Composite hat-stiffened panels are widely used in civil aircraft structural design as typical closed-section stiffened components with high load-carrying efficiency. To accurately predict the post-buckling bearing capacity and optimize the tapered termination design of such panels, this paper investigates the failure process of composite hat-stiffened panels with tapered ends through physical modeling and numerical analysis. A nonlinear failure analysis model is established by introducing the failure mechanisms of adhesive interfaces and composite laminates. The modeling method is verified against experimental results, showing discrepancies of 2.7% for buckling load and 3.5% for post-buckling failure load, respectively. Based on the validated numerical approach, parametric studies are carried out to analyze the effects of termination taper parameters on buckling and post-buckling mechanical behaviors. The results indicate that the termination taper design effectively adjusts the stiffness matching between stiffeners and skin and relieves local stress concentration. The optimal taper angle of 120° is recommended, where the failure load increases by 22% to 141.8 kN compared to the baseline configuration, significantly improving its post-buckling load-carrying capacity. The findings of this study can provide technical references for the design of stiffened composite panels with tapered stringer terminations in aerospace engineering. Full article

The deposition of volcanic ash in areas affected by erupting volcanoes can contaminate the soil with heavy metals, thereby jeopardizing food security and public health. This study focused on the use of compost for the bioremediation of this type of contaminated soil and on evaluating the effectiveness of this remediation technique in a horticultural crop. To this end, composts made from organic waste generated in the areas with volcanic-ash-affected soil, such as crop residues, cow manure, and cheese whey, were used. The design and optimization of the composting process for these wastes were described using three piles with the same proportion of crop residues and cow manure but different doses of whey (pile 1: without whey, pile 2: whey diluted with water (1:2 (v:v)); and pile 3: with undiluted whey) and by monitoring the evolution of physicochemical and biological parameters throughout the compositing process. The effectiveness of the composts obtained for soil remediation was evaluated by assessing the physiological response of a lettuce crop in pots. Five treatments were used: control soil without fertilization, inorganic fertilization, and the three composts obtained. The main agronomic properties of the soil and heavy metal availability were measured, along with the physiological and chemical parameters of the lettuce, including growth and macronutrient and heavy metal content. The results obtained in the composting experiment showed that the addition of cheese whey only affected the rate of organic matter degradation and the salt content of the final composts, without negatively affecting the stability and humification of their organic matter or their plant nutrient content. In the pot experiment, all composts improved soil fertility and reduced the availability of Ni, As, Cd, and Pb, but this did not consistently reduce uptake into lettuce, except in the case of Pb. Therefore, it is advisable to adjust the compost application rate and optimize crop selection to minimize the impact of heavy metals on the food chain, thereby ensuring safe production. Full article

The tectonic setting of Taiwan and its surrounding regions is characterized by the complex interaction between the northwest-oriented Ryukyu subduction zone and the east-oriented Manila subduction zone. Within this subduction framework, the elastic thickness of the lithosphere (Te) serves as a critical parameter for elucidating the mechanical behavior of the area. In this study, we employed the admittance–correlation method to estimate Te values across Taiwan and adjacent territories. The findings indicate that sedimentary loading results in an overestimation of the maximum Te by approximately 50 km; after adjustment, the Te values range from 0 to 60 km throughout the study area. On Taiwan, Te values predominantly lie between 20 and 30 km, decreasing to 10–20 km near the margins adjacent to the Ryukyu and Manila subduction fronts. The Philippine Sea Plate exhibits comparatively higher Te values, ranging from 40 to 65 km. The spatial distribution of Te broadly corresponds with major tectonic subdivisions. Statistical analyses reveal a weak negative correlation between Te and surface heat flow (r = −0.44) and a weak positive correlation with shear-wave velocity anomalies at a depth of 100 km (r = 0.22), suggesting that the thermal structure exerts only a moderate influence on lithospheric strength in this region. Nonetheless, within oceanic crustal domains, the relationship between Te and oceanic crustal age largely adheres to models of crustal cooling and lithospheric thickening, consistent with isotherm depths of approximately 200–400 °C. Additionally, dynamic topography associated with slab subduction may locally diminish Te by up to 25 km. Cross-sectional profiles through northern Taiwan and the Philippine Sea block reveal pronounced coupling between subduction geometry and Te distribution. The observed spatial patterns of Te reflect the mechanical imprint of prolonged tectonic evolution, with the orientation of Te gradients generally aligned with the direction of maximum principal compressive stress. Collectively, these results suggest that subduction geometry and tectonic processes are important factors influencing the spatial variability and evolutionary trajectory of lithospheric strength in Taiwan and its environs. Full article

Small-object detection in urban remote sensing imagery is essential for smart city applications, yet remains challenging due to limited target size, large scale variations, complex urban backgrounds, as well as the trade-off dilemma between detection accuracy and deployment-oriented efficiency. To address these issues, this paper proposes LMGANet, a parameter-efficient and real-time YOLOv11-based detector for urban remote sensing object detection. A C3K2-GDF module is introduced to enhance small-object representation through adaptive receptive-field adjustment and dynamic feature refinement. An Adaptive Multi-scale Feature Aggregation Network (AMFAN) is designed to strengthen cross-scale feature interaction and improve the fusion of spatial details and semantic information. In addition, a Lightweight Enhanced Shared (LES) detection head is developed to reduce parameter redundancy while preserving localization accuracy for small targets. Experiments on the VisDrone2019 and AI-TOD datasets show that LMGANet improves mAP50 by 4.8% and 3.2% over YOLOv11S, respectively, with only 3.63 M parameters and real-time inference capability. These results demonstrate that LMGANet achieves an effective balance among detection accuracy, parameter efficiency, and real-time inference performance for urban remote sensing applications. Full article

This study investigates the relationship between energy indicators and human development in South Africa over the period 1980–2023, employing a quantitative research design. Using secondary annual time-series data, the study examines the effects of electricity generation, per capita energy consumption, Oil-related fiscal revenue share as a share of total government revenue, and total energy consumption on the Human Development Index. The Autoregressive Distributed Lag (ARDL) bounds testing approach is employed to assess long-run and short-run relationships, complemented by Error Correction Models (ECM) to capture dynamic adjustments. Unit root and stability tests, including CUSUM and CUSUMSQ, ensure the robustness of the estimations, while Granger causality tests explore predictive linkages among variables. The findings reveal a positive long-run relationship between electricity generation and total energy consumption with human development, highlighting the importance of reliable and broad-based energy utilisation for enhancing welfare outcomes. In contrast, per capita energy consumption and Oil-related fiscal revenue share exhibit negative long-run effects, suggesting inefficiencies in energy use and the fiscal risks associated with reliance on oil-related government revenue. Short-run dynamics indicate that temporary adjustments, such as infrastructure expansion and transitional fiscal spending, can produce immediate but contrasting effects on human development. Granger causality analysis identifies unidirectional predictive relationships from electricity generation and Oil-related fiscal revenue share to human development, while total energy consumption exhibits weak bidirectional causality. Diagnostic tests confirm the model’s reliability and parameter stability over the study period. The results imply that energy policies in South Africa should prioritise efficient and inclusive energy use, ensure effective allocation of energy-related fiscal resources, and complement energy system improvements with broader socio-economic interventions. This study contributes to the understanding of the energy–development nexus in emerging economies, offering evidence-based insights for policymakers seeking sustainable human development. Future research could extend the analysis to provincial or sectoral levels, consider emerging energy technologies, and explore alternative development proxies to capture more nuanced socio-economic dynamics. Full article

Terahertz (THz) fingerprint detection is central to identifying characteristic absorption fingerprints of biomolecules derived from their intrinsic rotational and vibrational modes. The development of guided-mode resonance (GMR) technology together with pixelated design offers a new approach to enhance the recognition capability of such fingerprint spectra. Here, a novel secondary grating metasurface based on cycloolefin polymer (COP) is proposed, which adopts an ultra-minimalist dual-pixel complementary architecture to excite high-quality (Q)-factor GMR. Its spectral resolution does not exceed 50 GHz, enabling precise capture of target molecular characteristic information and meeting the requirements of broadband fingerprint sensing. More importantly, the design regulates the dual-pixel grating units through parameter gradient optimization and incorporates a dual regulation mode of static pixel-targeted coverage and dynamic angle fine tuning. By adjusting geometric parameters and incident angles, broadband coverage from 1.15 THz to 2.20 THz is achieved, which can accurately match the multi-fingerprint detection requirements of glutamic acid (Glu) and glutamine (Gln). This metasurface sensor, integrating the advantages of pixelation and high-Q-factor GMR characteristics, provides an effective strategy for enhanced broadband THz fingerprint sensing and shows broad application potential in the field of biochemical trace detection. Full article

Background: Tooth extraction (TE) after chemoradiotherapy is common in locally advanced nasopharyngeal carcinoma (LA-NPC), yet its determinants remain unclear. We evaluated the association between the Comprehensive Repair–Inflammation Index (CRII), reflecting systemic inflammation and host repair capacity, and TE risk after concurrent chemoradiotherapy (CCRT). Methods: We conducted a retrospective analysis of 354 patients with LA-NPC treated with definitive CCRT. The primary endpoint was post-treatment TE (none vs. ≥1). CRII was calculated from pre-treatment laboratory parameters and analyzed continuously, with a breakpoint identified via segmented regression. Logistic regression and restricted cubic splines were used. Multivariable models adjusted for clinical variables and mandibular dosimetric parameters (mean dose, V50, V60). Results: TE occurred in 70.1% of patients. CRII was significantly higher in those with TE (147.5 vs. 122.0; p < 0.001). CRII was strongly associated with TE (per 10-unit increase: OR 1.49, 95% CI 1.34–1.66; p < 0.001). A nonlinear relationship was observed, with a breakpoint at 145.7, above which TE rates increased markedly (90.5% vs. 58.8%; p < 0.001). CRII remained independently predictive after adjustment (adjusted OR 1.46; ≥145.7: OR 5.1; both p < 0.001). Mandibular dose parameters were not significantly associated with tooth extraction in this analysis. Conclusions: CRII independently predicts post-CCRT TE with a nonlinear risk pattern, highlighting the potential contribution of systemic host-related factors alongside conventional dosimetric parameters. Full article

The deterioration of mirror coatings in aggressive environments is one of the main causes of staining, which is a manifestation of corrosion. Electrochemical Impedance Spectroscopy (EIS) allows the electrochemical behavior of these coatings to be evaluated. However, an issue with ANNs is that to perform predictions with high accuracy, it is necessary to adjust their parameters using a large amount of samples. Depending on the ANN architecture, the requirement can range from hundreds to thousands of data points. This is a problem in many real cases, since measurements are expensive in terms of time and resources. In this study, we use a Transfer Learning approach. First, we generate and use synthetic data to train a neural network; then, real data are used to fine-tune the model. The results show that the ANN can identify patterns of coating deterioration with high accuracy and provides an effective mechanism for early performance evaluation. A high accuracy of 0.98 is achieved in the advanced stage, which means that the ANN detects severely damaged protective coatings. For the initial stage, an accuracy of 0.71 and a recall of 0.56 are obtained, indicating that the model has significant difficulty detecting initial damage due to very subtle changes, in the low signal versus noise ratio and the behavior of the protective coatings’ properties when they are close to their intact state. Full article

Wind-storage coordinated frequency regulation enhances the frequency stability of large-scale wind power systems. However, existing methods often rely on fixed parameters, limiting adaptability and accelerating energy storage depletion. To address these limitations, a coordinated control strategy based on dynamic weighting coefficients and model predictive control (MPC) is proposed. First, a dynamic weighting mechanism is designed to adaptively adjust the contributions of virtual inertia and droop control based on the system frequency state and the energy storage system’s (ESS) state of charge (SOC), thereby avoiding abrupt power variations and maintaining the SOC within safe limits. Second, an MPC-based rolling optimization model is established to continuously allocate the active power outputs between the doubly fed induction generator (DFIG) and the ESS, aiming to minimize both frequency deviations and regulation costs. Simulation results demonstrate the superiority of the proposed strategy. Under a step load disturbance, the maximum frequency deviation is reduced by 11.3%, and the peak time is shortened by 13% compared to conventional droop control. Furthermore, under continuous load fluctuations, the proposed approach significantly mitigates SOC depletion and minimizes system frequency fluctuations, proving its effectiveness in enhancing the frequency resilience of wind-storage combined systems. Full article