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Effects of density turbulence on helicon wave propagation in the core plasmas
No full textRadio frequency wave propagation can be significantly affected by density irregularities, such as filaments in the scrape-off layer or instabilities in the core plasma. In this study, we examine the impact of edge turbulence on helicon wave propagation using the Petra-M simulation tool. To analyze the effect of edge turbulence, we utilize a realistic background plasma derived from XGC simulations, which includes spatial density fluctuations at the edge. This focus is particularly relevant for the DIII-D configuration, characterized by edge density turbulence of the core plasmas in a wide pedestal QH-mode. We focus on helicon wave propagation in the core plasma since the slow mode cannot propagate into the core plasma when the density is higher than the lower hybrid resonance, where a wide pedestal QH-mode occurs. The simulation results indicate that edge density fluctuations have a substantial impact on helicon wave coupling due to scattering in the core. We specifically demonstrate that the toroidal mode number and the level of density fluctuations are significant factors influencing scattering. While we have minimized the excitation of slow modes from the antenna, we still observe mode-converted slow modes resulting from the incoming helicon waves. The insights derived from these simulations will inform upcoming tokamak experiments regarding helicon antenna coupling in long pulse scenarios
Retraction Notice: A Review of Different Configurations and Control Techniques for DSTATCOM in the Distribution system
No full textWe take a zero tolerance to any situation where fraudulent research is published in our journals. As a result, this article has been retracted by the Publisher because it is suspected to be a nonsensical computer-generated publication with a number of tortured phrases and irrelevant references.
Additional measures have been implemented to prevent these issues from reoccurring.
EDP Sciences is extremely grateful to anonymous whistleblowers and the Problematic Paper Screene
Total Phenol and Tannins Test of Ethanol Extract of Keji Beling Leaves
No full textKeji beling (Strobilanthes crispa Bl.) is an herbal plant that contains bioactive compounds, including phenols, tannins, alkaloids, saponins, and polyphenols, which have the potential to exhibit antioxidant, antibacterial, and anticancer properties. This study aims to determine the total levels of phenols and tannins in the ethanol extract of Keji beling leaves using the UV-Vis spectrophotometry method as a scientific basis in the development of herbal products. The extraction process is carried out through maceration using 96% ethanol. The phenol content was determined by the Folin–Ciocalteu reagent at a wavelength of 798 nm, while the tannins were analyzed using the Folin-Denis reagent at a wavelength of 650 nm. Data analysis was carried out using one-way ANOVA. The results showed that the total phenol content was 102,350 μg GAE/g at 1000 ppm and 144,700 μg GAE/g at 500 ppm, and the tannin content was 24,382 mg TAE/g extract. The phenol and tannin composition detected in the extract demonstrates a significant contribution to the pharmacological potential of Strobilanthes crispa Bl. in the development of herbal medicines with antioxidant efficacy, making it a valuable resource for the development of phytopharmaceuticals and the sustainable use of local natural resources
Relationship Between Age at Menarche and Contraceptive Use with
No full textUterine leiomyoma is a benign tumor whose growth is strongly influenced by Estrogen, particularly through Estrogen Receptor Alpha (ERa). Risk factors such as age at menarche and contraceptive use are suspected to play a role in uterine leiomyoma; however, the direct relationship has not been widely studied. This study aimed to investigate the relationship between age at menarche and contraceptive use with ERa expression in uterine leiomyoma tissues of patients at RSI UNISMA. This study was an observational analytic study with a cross-sectional approach. The sample consisted of 21 uterine leiomyoma tissue specimens from patients who had undergone hysterectomy or myomectomy. Secondary data were obtained from medical records. ERa expression was analyzed using immunohistochemistry and manually quantified with ImageJ software. Data were analyzed using linear regression. A total of 66% of patients had a normal age at menarche (10-16 years), and 61% used hormonal contraceptives. The age at menarche and hormonal contraceptive use were not correlated with ERa expression (p > 0.05), although each factor contributed 1% and 6% to the variation in ERa expression. There is no correlation between age at menarche or contraceptive use and ERa expression in uterine leiomyoma tissues of patients at RSI UNISMA
Integrated Rice Husk Thermal Dampening Layer for Temperature Suppression and Efficiency Enhancement in Photovoltaic Modules
No full textThis study investigates the use of a rice husk-resin composite as a passive thermal dampening layer to reduce temperature rise in photovoltaic (PV) modules. High operating temperature remains a major performance barrier for PV systems, particularly in tropical regions where solar radiation is consistently high, leading to reduced voltage, efficiency, and long-term material degradation. To address this issue, a bio-insulating composite made from waste rice husk is proposed as a low-cost, environmentally friendly thermal suppressor. The composite layer was attached directly to the rear surface of the PV module and tested against a baseline module under natural outdoor conditions. Temperature, electrical parameters, and irradiance were recorded using thermocouples, a data logger, and standard PV instrumentation. The results show that the composite effectively reduces module temperature by approximately 2-3°C, increases open-circuit voltage, improves fill factor, and enhances overall electrical performance. The maximum power point (MPP) increased by up to 20.7% compared with the module without the thermal dampening layer. These findings demonstrate that rice husk-resin composite provides a practical passive cooling solution and offers a promising pathway for boosting PV performance in hot climates
Mechanical model of fatigue damage mechanism and development process of hydraulic support
No full textHydraulic support is a key supporting structure in coal mine engineering, bearing complex loads. Existing studies mostly focus on single factors, such as mechanical load, stress distribution, or temperature change, ignoring their interaction. To comprehensively analyze the fatigue damage of hydraulic support, this paper designs a mechanical model based on multi-physics coupling, combined with finite element analysis, and systematically studies the fatigue damage mechanism and development process of the support under complex working conditions. First, multi-physics coupling analysis is carried out to establish the geometric model of the support, and the interaction between the thermal field, mechanical field, and corrosion field is combined to simulate the working state of the support under complex working conditions. The thermal-structural coupling analysis module is used in combination with the corrosion model to evaluate the influence of temperature change and environmental factors on the fatigue damage of the support. After that, the Morrow fatigue model is selected to calculate the damage accumulation in the loading cycle, and the crack propagation process is simulated in combination with the Paris law. Numerical simulations are carried out. Firstly, static and dynamic load analysis is carried out, and then, the cyclic loading is applied. The stress distribution of the support is calculated, and the stress concentration area and the location of fatigue damage are identified. Finally, the response surface method is used to optimize the model parameters, and the Monte Carlo simulation is used to perform uncertainty analysis to verify the model’s accuracy and reliability. Experiments show that the remaining life of hydraulic supports with different damage degrees can be successfully predicted, and the safety factor of hydraulic supports with support strength ranging from 0.8 Mpa to 1.6 Mpa is kept above 0.5
Design optimization and experimental assessment of DC motor for robotic actuation using finite element analysis
No full textRobotic actuators need to be light weight, compact, and efficient for meeting the requirement of size and controllability. It's capability of achieving high power density is often restricted by limitations in torque output and efficiency. This paper presents a novel multi-module spliced direct-drive outer rotor BLDC motor tailored for robotic systems. This study focuses on a unique multi-module splicing structure that simplifies manufacturing and assembly while significantly enhancing torque density through improved magnetic symmetry and inherent structural modularity. Critical electromagnetic parameters—pole-arc coefficient, air gap, and permanent magnet thickness—are systematically refined using combined theoretical modeling and high-fidelity simulations in ANSYS Maxwell. A quasi-Newton multi-objective optimization algorithm accelerates convergence toward globally optimal configurations, effectively balancing multiple design objectives. Optimized results confirm a peak efficiency of 95.06%, core and copper losses reduced to 22.5 W and 12.8 W respectively, a 38.89% reduction in cogging torque, an 8.33% decrease in air-gap flux density, and torque ripple maintained at 24% in simulations, primarily attributed to the 12th harmonic. Prototype testing validate these improvements, with actual torque ripple slightly higher than the simulated value at 26%, while demonstrating agreement with simulation data in efficiency and losses. By integrating structural design, computational optimization, and experimental verification, this work delivers a robust solution to the persistent high torque density versus manufacturing feasibility trade-off, enabling more efficient, reliable, and scalable robotic actuations
Controllable Synthesis of Hydroxypropyl Starch and Its Application in Hollow Capsules
No full textHydroxypropyl starch (HPS) is widely used in various applications due to its unique functional properties, but optimizing its molecular characteristics for specific applications remains a challenge. This study aimed to optimize the process parameters for producing HPS capsules with desirable molecular and performance properties. The mass fraction of the etherification reagent, reaction pH, reaction temperature, and reaction duration were controlled to create HPS with varying degrees of substitution (DS). Acid solution degradation was used to prepare HPS of varying molecular weights (MW), and cold-gelation was employed to prepare hollow HPS capsules. A rigorous evaluation of performance indicators was conducted, and response surface methodology (RSM) was used to examine the effects of solid content, MW, and dipping temperature on capsule performance. Experimental results showed that these factors influenced performance in the following order: solid content > molecular weight > dipping temperature. Optimal parameters were identified as a solid content of 18%, an MW of 77 kDa, and a dipping temperature of 57 ℃, yielding capsules with a wall thickness of 0.086 mm, a disintegration time of 328 s, and moisture absorption of 8.594%. These findings provide valuable insights for the tailored design of HPS capsules, which could enhance their utility in industrial applications
The Existence of Solution to the Even Orlicz Chord Minkowski Problem
No full textChord measures are newly discovered translation-invariant geometric measures of convex bodies in Rn by Lutwak-Xi-Yang-Zhang (Communications on Pure and Applied Mathematics, 2024), which is an extension of the surface area measure. The Minkowski problems for chord measures was considered by Lutwak-Xi-Yang-Zhang. In this paper, we use variational method to solve the even Orlicz chord Minkowski problem. The obtained results are an extension of the even Orlicz Minkowski problem from Haberl-Lutwak-Yang-Zhang (Advances in Mathematics, 2010 )
Prediction of natural ventilation performance through a comparative study of interior void and courtyard void designs in two-storey urban row houses
No full textNatural ventilation is an important passive design strategy for improving indoor environmental quality while reducing dependence on energy-intensive mechanical cooling systems. However, in dense urban contexts, two-story row houses often face airflow limitations due to compact layouts, narrow facades, and limited openings. This study aims to predict and compare the performance of two natural ventilation strategies, namely interior void and courtyard void. The research methodology uses three analytical approaches: Convex Space and Computational Fluid Dynamics (CFD) simulations to evaluate airflow circulation patterns, velocity distribution, and indoor temperature. The study was conducted on a two-story row house prototype at Summarecon Residence, Bekasi, with a floor plan area of 6 × 14 m (84 m2 per floor). The position and dimensions of the inlet and outlet were made the same in each scenario, while external parameters such as average wind speed and outside temperature in 2024 were used in the simulation. The results show that the courtyard void produces better ventilation performance with an average wind speed of 2.17 m/s and a temperature of 33 °C, compared to the interior void, which only reaches 1.17 m/s with a temperature of 33.43 °C. In addition, the area near the courtyard had a maximum wind speed of 6–7 m/s, while the interior void had 5-6 m/s. These findings provide evidence-based recommendations on the importance of integrating passive ventilation strategies in row house design