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Studies of various lower hybrid wave launch scenarios for non-inductive start-up on TST-2
No full textEfficient non-inductive start-up of a spherical tokamak may be achieved by using lower hybrid waves that have high current drive efficiency. On the TST-2 spherical tokamak, three lower hybrid launchers are installed at the outer-midplane, top and outer-off-midplane to explore efficient start-up scenarios. The previously installed outer-midplane and top launchers were both found to drive current far off-axis where confinement of fast electrons were expected to be low. The outer-off-midplane launcher was newly developed to increase current drive by improving absorption closer to the magnetic axis. The outer-off-midplane launcher driven plasma was confirmed to have higher core electron temperature than those of the previous two launchers, and reduced fast electron losses compared to the top launcher
Comparative analysis of vibration, flexural, and Impact properties of PLA-ABS composites for structural applications
No full textThis work investigates the flexural and vibration characteristics of several PLA-ABS composites. Modal analysis was used to determine the intrinsic frequencies and mode forms of different composite constructions, providing information about their dynamic performance. According to the current vibration research, PLA40/ABS60 displayed the highest mode 1 and mode 2 frequencies, indicating higher resistance to secondary vibrations, while PLA60/ABS40 produced an extraordinarily high mode 3 frequency of 928.75 Hz, showing enhanced rigidity. The results show that the resonance peaks shift to higher frequencies when ABS is added, indicating improved damping and stiffness properties. PLA100 and ABS/PLA/ABS composites had the highest maximum stress, indicating greater strength, according to tests of flexural modulus and impact strength. The greatest deflection was displayed by PLA40/ABS60, indicating increased flexibility but decreased strength. In impact tests, PLA50/ABS50 had the best energy absorption and durability with the maximum impact strength of 9757.47 J/m, closely followed by PLA100. Therefore, sandwich configurations like ABS/PLA/ABS enhance vibrational behavior and dynamic performance, whereas PLA/ABS composites with ideal blending ratios strike a balance between strength and flexibility
Validation of ERMES 20.0 finite element code for JET A2 antennas coupling studies
No full textThis study presents the validation of the finite element code ERMES 20.0, benchmarked against the well-established method-of-moments code TOPICA. The simulations focus on Ion Cyclotron Resonance Heating (ICRH) coupling for the JET A2 antennas. Validation is performed by comparing two key metrics: the scattering parameter matrix (S-matrix) and the electric field distribution in front of the antenna. These parameters are critical for assessing ICRH antenna-plasma coupling efficiency and understanding interactions with plasma-facing components. The results show a strong agreement between ERMES 20.0 and TOPICA, confirming the accuracy and reliability of the finite element approach. This comparative analysis highlights the capability of ERMES 20.0 to support advanced modeling of sheath rectification and wave–edge plasma interactions, which are central phenomena in ICRH system design and optimization
Spectroscopic, biological activity and scanning electron microscope studies of Pd (ii) with Tetrazole-thione and Phosphines complexes
No full textFive mixed-ligand phenyl Palladium (II) complexes containing 5-henzylthion-lH-tetrazole (LH) and phosphines (1-5) were synthesized. These complexes are classified into one groups: [PdL2(dppm)], [PdL2(dppe)], [PdL2(dppp)], [PdL2(dpph)], [PdL2(dppf)], (1,5). The complexes were prepared with moderate to high yields and characterized by various techniques. The characterization data indicated that the L-ligand acts a monodentate ligand through the nitrogen atom in the tetrazole ring in complexes (1-5), adopting a square planar geometry around the Pd(II) center. The crystal structure of the complexes was examined using scanning electron microscopy (SEM), and the results revealed the presence of normal nanostructures
Finite element analysis of wind-induced response in tapered steel floodlight poles with varied luminaire configurations
No full textStadium floodlight poles are tall, slender structures that are especially sensitive to wind loads, which often shape their design and construction. This study uses finite element analysis in STAAD. Pro to examine a 30-meter tapered steel floodlight pole. Wind loads are calculated as per IS 875 (Part 3): 2015. The analysis primarily focuses on a comparative study of four regular luminaire headframe configurations with flexibility and structural performance in mind. The result of the numerical calculations indicated that the adjustable brackets could increase the lateral deflection of the structure by as much as 7.7%. Due to the introduction of brackets, the peak stress value increased by 34% due to stress concentration. This was compared against the baseline case of the most critical wind zone having a wind speed of 61 m/s. The base pole can deflect as much as 530.795 mm due to wind loads. This is 12.5 times higher than the IS 800 serviceability limit of 100 mm. Thus, performance penalties of actual headframe designs must be measured. Also, such structures must be checked for serviceability early on since meeting strength requirements does not guarantee safety and usability of wind-sensitive structures
Onset of High-Harmonic Fast Wave Propagation in Annulus Geometry
No full textPrevious experiments on NSTX have reported high-harmonic fast wave (HHFW) power losses in the scrape-off layer (SOL), with dependencies on the wave parallel wavenumber, plasma density, and magnetic field. This study presents an analysis of HHFW propagation in the SOL plasma, focusing on parasitic coupling to the waveguide mode bounded by the steep gradient pedestal and the outer wall boundary. The analytic and finite element wave models are discussed using a 2D annulus geometry, which serves as a simplified representation of the NSTX-U plasma. The model shows that a minimum radial gap width is required to support wave propagation, analogous to the higher-order modes in coaxial geometries. The impact of several factors, including gap width, wave parallel phasing, and magnetic field strength, on parasitic wave coupling is examined, highlighting the role of the geometric dimension in relation to the wave perpendicular wavelength. The findings suggest that controlling the edge/SOL density profile (gap control) is crucial for mitigating parasitic coupling when the density in front of the antenna exceeds the density cutoff
Enhancing wear and erosion resistance of partially oxidized NiCrBSiFeC coating by plasma spray on MDN431 substrate
No full textThis study investigates the enhancement of wear and erosion resistance through partial oxidization of NiCrBSiFeC alloy powders applied as coatings on MDN431 steel. Using a flame spray process, alloy powders were sprayed into water under controlled parameters to produce partially oxidized powders with approximately 50% oxide layer and 50% metallic core, balancing hardness and ductility. These powders were deposited onto MDN431 steel via plasma spray to form coatings, which were characterized for microstructure, hardness, and phase composition. Wear and erosion tests, conducted from room temperature to 600°C, revealed superior performance of the coatings. At 600°C, 2 m/s, and 30 N load, the NiCrBSiFeC coating exhibited six times higher wear resistance than the MDN431 substrate. However, erosion tests at 600°C showed higher weight loss in coatings compared to the substrate, attributed to alumina particle embedment. The formation of oxide phases in the coating significantly enhanced its high- temperature wear and erosion resistance
Construction of generalized quasilinear diffusion coefficient using neural networks with physical restrictions
No full textThe quasilinear diffusion coefficient (DQL) derived from our machine learning framework shows comparable trends with the ground truth DQL obtained from GENRAY-CQL3D simulations. Additionally, for the strong absorption cases, the radial current drive profiles generated using the DQL from our model exhibit consistent behavior with those obtained from the original simulation. These findings indicate the potential of our surrogate modeling approach with physical restrictions to replicate key wave–plasma interaction characteristics while reducing computational costs. Traditionally, calculating DQL for wave–particle interactions relies on computationally intensive wave simulations coupled with Fokker–Planck solvers. To address this challenge, we developed a machine learning-based surrogate model with physical restrictions derived from cold plasma theory and bounce-averaged damping effects. First, we establish the propagation domain of Lower Hybrid Waves in the (N∥, ρ) space by identifying the accessibility limit and determining the upper and lower bounds of N∥ using the Potential Power Deposition (PPD) method. Subsequently, leveraging a database constructed using Latin hypercube sampling alongside the underlying physical restrictions (e.g. PPD), machine learning methods including U-Net and Recurrent Neural Networks are employed to design a physics-restricted machine learning framework capable of reconstructing DQL
Retraction Notice: A Survey on a Nonlinear Regression Application to Machine Learning Techniques for Geomagnetic Data Recons-truction Processing
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