Hasil untuk "Plasma engineering. Applied plasma dynamics"

Muhammad Ishfaq Khan, Meraj Ali Khan, Mujahid Iqbal et al.

Abstract In this paper, we investigate exact analytical solutions of the (2+1)-dimensional complex modified Korteweg–de Vries (CmKdV) system using the truncated M-fractional derivative together with the Jacobi elliptic function expansion method. The CmKdV system plays a central role in modeling nonlinear wave propagation in optics, plasma physics, and fluid dynamics. By applying the truncated M-fractional derivative, the system is transformed into a more tractable form, enabling the effective use of the Jacobi elliptic function expansion method to construct exact soliton and periodic wave solutions. The results offer deeper insight into the system’s nonlinear dynamics and highlight the robustness of the proposed method. Graphical simulations generated in Mathematica illustrate the physical behavior of the obtained solutions across multiple dimensions, such as two-dimensional, three-dimensional, and contour, and the influence of time on the wave propagations. Overall, combining the Jacobi elliptic function expansion method and truncated M-fractional derivatives creates a strong framework for solving complex differential equations, leading to new possibilities. Opportunities for research and development exist. This research adds to our understanding of the (2+1)-dimensional complex modified Korteweg-de Vries (CmKdV) system and demonstrates how theoretical mathematics can be applied to real concerns. Mathematical modeling and computational visualization can significantly impact engineering and science, and our findings promote a multidisciplinary approach to research.

Gabriela Brunosi Medeiros, Paulo Augusto Marques Chagas, Gustavo Cardoso da Mata et al.

Although recycled poly(ethylene terephthalate) (rPET) is an attractive, sustainable feedstock for electrospinning, optimization of processing variables for filtration performance remains limited. This study quantifies how polymer concentration, flow rate, and applied voltage govern fiber morphology and key filtration metrics—collection efficiency (<i>η</i>), pressure drop (Δ<i>P</i>), quality factor (<i>Q_f</i>), and porosity—in rPET membranes. A fractional factorial design was employed to model interactions and identify trade-offs in filtration performance. The optimal condition was obtained at 16 wt.% PET, 1.2 mL·h⁻¹, and 22 kV, yielding uniform fibers with an average diameter of 328.6 nm and high filtration efficiencies (95.65–99.99%). The permeability constants were 1.07 × 10⁻¹² m² (20 wt.% PET) and 1.15 × 10⁻¹³ m² (8 wt.% PET), indicating an increase in permeability with increasing polymer concentration and fiber diameter. The 20 wt.% PET membrane delivered the highest <i>Q_f</i> of 0.0646 Pa⁻¹ with a low Δ<i>P</i> of 48.5 Pa at 4.8 cm·s⁻¹, reflecting a favorable balance between collection and airflow resistance. In summary, higher PET concentrations reduce flow resistance and improve <i>Q_f</i>, whereas lower concentrations yield finer fibers and high <i>η</i> at the expense of permeability. rPET nanofiber membranes, therefore, represent a sustainable and versatile route to high-efficiency, lower-pressure-drop air filters for residential, industrial, and commercial environments.

Naeema Jafar, Adil Jhangeer, H. U. Rehman et al.

Yanan Wang, Liyun Jin, Kehui Zhou et al.

The transient ignition process of Hall thrusters generates pulse current surges with amplitudes tens of times higher than the steady-state discharge current, posing significant challenges to power supply systems and electrode reliability. However, in conventional thrusters, direct observation of internal plasma dynamics is hindered by the obstruction of discharge channel walls, and existing particle-in-cell (PIC) simulation results lack experimental validation, leading to bottlenecks in elucidating the spatiotemporal evolution of plasma parameters and developing surge current suppression strategies. In this study, an open-structured external-discharge Hall thruster is employed to achieve direct visualization of plasma channel dynamics during ignition for the first time. By integrating high-speed ICCD imaging, PIC-Monte Carlo collision simulations, and transient circuit modeling, the regulatory mechanisms of anode voltage and propellant mass flow rate on plasma parameters and current surges are investigated. Experimental results demonstrate that increasing the anode voltage from 180 V to 240 V accelerates electron energy accumulation (up to 55 eV), elevates the pulse current peak from 1.49 A to 2.96 A, and reduces the ignition duration by 40%. When the propellant flow rate rises from 0.3 mg s−1 to 0.7 mg s−1, the neutral atom density increases to 1.8 × 1021 m−3, significantly enhancing ionization rates and driving the current peak to 3.68 A. Key phenomena, including dual-ionization-zone coordinated discharge and axial plume expansion, are experimentally validated. Furthermore, a dynamic plasma impedance model is established to propose staged voltage initiation and graded flow regulation strategies, which reduce the electrical stress factor from 10.84 to 2.27. These findings overcome the limitations of traditional diagnostic methods and model validation, providing theoretical insights and engineering guidelines for designing high-reliability Hall thrusters and optimizing power system redundancy.

Satish Dhoke

The rapid advancement of digital technology has transformed education, making e-learning a vital instructional method. However, its adoption in rural areas, particularly among commerce students in Bhokardan, presents significant challenges. This study explores the level of digital literacy among students and identifies the barriers to e-learning adoption, focusing on factors such as resource limitations, digital infrastructure, and student readiness. A sample of 100 students was analyzed using the Chi-square test to examine the relationship between digital literacy, resource availability, and e-learning adoption. The findings indicate that low digital literacy serves as a significant barrier. At the same time, limited access to devices and unreliable internet connectivity also hinder adoption, though their impact is statistically less significant. Despite these obstacles, the study highlights opportunities to enhance e-learning through targeted digital literacy training and improved access to technological resources. The results emphasize the need for strategic interventions to strengthen digital literacy and infrastructure, which could significantly improve educational outcomes in rural areas.

Richard Amorin, Cornelius B. Bavoh, Bayorbor Yasmeen et al.

Refining is vital in the oil and gas industry, converting crude oil into products like gasoline, diesel, and LPG. Since discovering oil in 2007, Ghana’s petroleum sector has experienced significant growth; however, the country still relies on imports to meet its domestic demand, importing nearly four million metric tonnes of petroleum products in 2022, with gas oil (diesel) being the most significant component. This study, therefore, explored the potential benefits of refining Ghana’s crude oil, with a focus on its economic feasibility and the implications thereof. Considering the construction of a new refinery, a cost-benefit analysis was conducted using the Jubilee field crude oil, evaluating Net Present Value (NPV), Return on Investment (ROI), and Payback Period with the aid of Aspen HYSYS and an Excel Spreadsheet. The cost-benefit analysis indicated a positive NPV, a payback period of 3.5 years and an ROI of 29%. The predicted cost savings for local refining, with 2022 as a case, were estimated to be $1.4 billion (GH₵16.3 billion). By refining petroleum locally, an estimated net gain of $8.66 (GHS 96.99) per barrel was computed. A 2013 – 2033 forecast analysis projected increasing consumption volumes, rising import costs, and escalating ex-pump prices, further supporting the need for enhanced local refining capacity. The Government of Ghana should therefore prioritize refining crude oil locally as part of its industrialization strategy. This will help create jobs, generate foreign exchange savings, and enhance energy security.

Mahfudz Ahnan Al Faruq, Mohammad Givi Efgivia

This study introduces a Voice Frequency Detector (VFD) framework to enhance biometric password authentication by addressing key challenges such as spoofing attacks, environmental noise, and natural variations in speaker voice due to health, emotion, or aging. The system leverages dynamic vocal features including fundamental frequency (F0), Mel-Frequency Cepstral Coefficients (MFCCs), and formant structures, integrated with a hybrid CNN-BiLSTM deep learning model and attention mechanisms for robust spectral-temporal analysis. An anti-spoofing subsystem employs spectral flatness and phase distortion features to detect synthetic and replayed voices. The methodology involves signal preprocessing (Wiener filtering, voice activity detection), feature extraction, and score fusion by combining deep learning outputs with anti-spoofing results. Experiments on a dataset of 100 speakers and 1,000 spoofed samples demonstrate strong performance, achieving an EER of 2.8% in controlled conditions and 5.0% in noisy environments, with over 91% accuracy against replay, synthetic, and voice conversion attacks. Statistical analysis confirms that MFCCs are the most discriminative feature, contributing to 62% of the variance. The VFD framework offers a secure, adaptive, and practical voice authentication solution suitable for finance, IoT, and access control applications. Future enhancements may explore multi-modal integration and transformer-based architectures for broader applicability.

A. Norouzi, Masoumeh Chapalaghi, A. Hosseinkhani et al.

T. Furukawa, D. Kuwahara, Shunjiro Shinohara

The rotating magnetic field (RMF) acceleration method is a newly proposed approach to enhance the performance of electrodeless radio frequency (RF) plasma thruster. In the previous study, electron current drive in the azimuthal direction was observed using the RMF method, which resulted in the electromagnetic force in the presence of a magnetic nozzle. To further optimize the acceleration effect with the RMF method, we investigated the dependence of spatial profiles of plasma parameters and the driven current density on the RMF field strength. We observed a higher azimuthal-current density in plasma compared to the previous campaign. According to spatial electrostatic probe measurements, the ion Mach number spatially increases with the increase in RMF strength. The ion acceleration on the z-axis can result from the presence of spatial convergence of electron pressure due to radial electron transport. Total thrust composed of a static pressure term and electromagnetic force increases with higher RMF strength under the full penetration condition of the RMF. We clarified the strengthening RMF field contributes to the enhancement of the azimuthal current and spatial ion acceleration effect, leading to the thrust increment. These findings, although the thrust performance is not yet at a practical level, hold significant potential for the future optimization of the RMF acceleration method applied to electrodeless RF plasma thrusters.

Seonghee Kim, Sungho Lee, O. Li

Herein, we applied plasma engineering to modify the Fe‐N complex directly on the graphene nanoplatelet (GNP) substrate as advanced ORR electrocatalysts. Plasma treatment activated and effectively anchored the Fe‐N4 structure on GNP without degradation. From XPS analysis, the binding energy of Fe 2p was shifted towards higher energy in FePc/GNP‐Plasma with enhanced charge delocalization of Fe–N complex. Electrochemical analyses showed FePc/GNP‐Plasma electrocatalyst achieved a half‐wave potential of 0.91 V vs. RHE and six times higher kinetic current density compared to commercial 20 wt.% Pt/C. The results highlight that forming the charge delocalization via plasma engineering promotes ORR activity, offering new insights for plasma surface modification of carbon‐based electrocatalysts for renewable energy applications, including fuel cell and metal‐air batteries.

Paloma E. S. Pellegrini, Silvia V. G. Nista, Stanislav Moshkalev

The demands for high resolution fabrication processes are ever-increasing, with new and optimized methodologies being highly relevant across several scientific fields. We systematically investigated thermal scanning probe lithography process and detailed how tuning temperature and probe contact time on the sample can optimize patterning and achieve 10 nm resolution. Additionally, we propose a novel fabrication methodology that integrates thermal scanning probe lithography and bilayer liftoff, achieving sub-20 nm resolution of the final metallized structures. Each step of the process, from sample preparation to the final liftoff, is described in detail. We also present a quantitative analysis comparing the accuracy of the lithography process to that of the bilayer liftoff. Finally, we show the feasibility of using thermal scanning probe lithography for the fabrication of photonic devices by validating our work with promising dipole geometries for this field.

G.Minni, Sayyed Nagulmeera, B Bhagya Lakshmi et al.

Generative artificial intelligence, enabled through sophisticated machine learning frameworks, such as Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs), is disrupting the creative landscape within many of the creative industries, opening a new set of tools for content creation. Therefore, this article investigates the disruptions generative models present across multiple aspects of creative production, focusing on the influences of art, music, literature, and design. In the visual arts, generative AI produces original artworks that blend aesthetics and styles that extend conventional notions of creativity; in music, AI-composition tools allow musicians to compose original musical works and experiment with entirely new genres. In literature and storytelling, the same generative processes offer AI systems the ability to propose narrative frameworks and other textual elements that may instigate human writers to take these concepts further with a narrative or may stand on their own as original content. In design, generative algorithms support product development all the way down to quickly prototyping new products. The paper includes specific case studies or outlines of the application of generative AI tools to proposed projects, a discussion of effectiveness with the respective generative model, and the potential limitations generative models present for each creative area. The paper will also reflect on the threats generative AI may pose, the potential to redefine human creativity, originality, and ownership, implications for the potential decision-making capabilities of these systems, and if there may be consequences for society. In all these considerations, there are opportunities for and more significant implications of the potential of generative AI to assist and expand human creative possibilities throughout the entire creative process.

Walia Binte Tarique, Md Habibur Rahaman, Shahriyar Safat Dipta et al.

Organic solar cells (OSCs) are becoming increasingly popular in the scientific community because of their many desirable properties. These features include solution processability, low weight, low cost, and the ability to process on a wide scale using roll-to-roll technology. Enhancing the efficiency of photovoltaic systems, particularly high-performance OSCs, requires study into not only material design but also interface engineering. This study demonstrated that two different types of OSCs based on the PTB7-Th:IEICO-4F and PM6:Y6 active layers use a ZnO bilayer electron transport layer (ETL). The ZnO bilayer ETL comprises a ZnO nanoparticle (ZnO NP) and a ZnO layer created from a sol-gel. The effect of incorporating ZnO NPs into the electron transport layer (ETL) was studied; in particular, the effects on the electrical, optical, and morphological properties of the initial ZnO ETL were analyzed. The ability of ZnO films to carry charges is improved by the addition of ZnO nanoparticles (NPs), which increase their conductivity. The bilayer structure had better crystallinity and a smoother film surface than the single-layer sol-gel ZnO ETL. This led to a consistent and strong interfacial connection between the photoactive layer and the electron transport layer (ETL). Therefore, inverted organic solar cells (OSCs) with PTB7-Th:IEICO-4F and PM6:Y6 as photoactive layers exhibit improved power conversion efficiency and other photovoltaic properties when using the bilayer technique.

Nikita Pathak, Alok Kumar Srivastav

Ayurveda, an ancient Indian medical system, emphasizes the use of natural elements to treat diseases and promote a balanced, healthy life. Polyherbalism—the practice of combining multiple herbs—enhances therapeutic efficacy and reduces toxicity. In this study, three medicinal plants, Moringa oleifera, Withania somnifera, and Acorus calamus, were examined for their antimicrobial and antioxidant properties. Phytochemical screening of these plants identified active compounds like alkaloids, tannins, saponins, and flavonoids. Solvent extractions using methanol, chloroform, petroleum ether, and water were conducted, and antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, B. cereus, and Pseudomonas aeruginosa using the disc diffusion method. Additionally, antioxidant properties were measured with the DPPH radical scavenging assay. This research highlights the potential of these plants to combat microbial infections and oxidative stress-related disorders.

K. Ilyenko, V.M. Gurdzhian, V.P. Dzyuba et al.

A study of operation of non-incandescent cathode of X-band magnetron is reported, which employs field electron emission thin foil sharp blade-type sources to instigate the primary emission of electrons. We discuss conditions and practical considerations necessary to provide stable operation of the cathode. The problem of engineering and manufacturing a reliable design of totally non-incandescent magnetron cathode turned out to be rather challenging: in the existing cathode-anode block configurations one needs to fulfil conditions for efficient FEE at a given operating level of applied A-K voltage (for non-relativistic magnetrons of the order of 10 kV for A-K gaps in the units of millimetres) and then ensure sufficient level of SEE to develop electron cloud capable of producing enough output magnetron microwave power. Moreover, introduction of thin foil sharp blade/knife-edge sources of FEE essentially into the A-K gap of a magnetron anode block should be done in a manner not disrupting electron cloud-anode slow-wave structure interaction resulting in production of microwave output power. Finding of appropriate engineering solutions to these goals is done on test A-K gaps at the design stage; however, in the manufactured packaged device, one can also trace evidence of described emission processes. Although there is no complete theory of a pre-oscillating dynamics of space-charge cloud in a magnetron, experimentally the leakage current provide a means of an insight into the development of electron cloud. The leakage current (as well as the back cathode bombardment) is a manifestation of a kind of nonlinear collective space-charge cloud oscillation in a non-neutral magnetically insulated electron plasma of the cloud. Accepting such a viewpoint, we can trace the onset of primary electron current as measurable anode leakage current in the pre-oscillating packaged magnetron. We can also experimentally observe the saturation of the FEE current as manifested by the saturation of the anode current before the start of microwave generation.

Sami T. Tuomivaara, Chin Fen Teo, Yuh Nung Jan et al.

Abstract To facilitate our understanding of proteome dynamics during signaling events, robust workflows affording fast time resolution without confounding factors are essential. We present Surface-exposed protein Labeling using PeroxidaSe, H 2 O 2, and Tyramide-derivative (SLAPSHOT) to label extracellularly exposed proteins in a rapid, specific, and sensitive manner. Simple and flexible SLAPSHOT utilizes recombinant soluble APEX2 protein applied to cells, thus circumventing the engineering of tools and cells, biological perturbations, and labeling biases. We applied SLAPSHOT and quantitative proteomics to examine the TMEM16F-dependent plasma membrane remodeling in WT and TMEM16F KO cells. Time-course data ranging from 1 to 30 min of calcium stimulation revealed co-regulation of known protein families, including the integrin and ICAM families, and identified proteins known to reside in intracellular organelles as occupants of the freshly deposited extracellularly exposed membrane. Our data provide the first accounts of the immediate consequences of calcium signaling on the extracellularly exposed proteome.

Haibin Tang, Thomas M. York

Haibin Tang, Thomas M. York

C. Neuroth, Z. Mujahid, B. Berger et al.

Dielectric barrier discharges (DBDs) are promising tools for air pollution removal and gas conversion based on excess renewable energy. Catalyst loading of dielectric pellets placed inside the plasma can improve such processes. The effects of such metallic and dielectric catalyst loading on the discharge are investigated experimentally. A patterned DBD is operated in different He/O2 mixtures and driven by a 10kHz pulsed rectangular voltage waveform. Hemispherical dielectric pellets coated by different catalyst materials at different positions on their surface are embedded into the bottom grounded electrode. Based on phase resolved optical emission spectroscopy the effects of different catalyst materials and locations on the streamer dynamics are investigated. The propagation of cathode directed positive volume streamers towards the apex of the hemispheres followed by surface streamers, that move across the structured dielectric, is observed for positive applied voltage pulses. Coating the apex with a conducting catalyst results in attraction of such streamers towards the apex due to charging of this surface, while they avoid the apex in the presence of a dielectric catalyst. Surface streamers, that propagate across the hemispheres, are stalled by conducting catalysts placed on the embedded pellets as rings of different diameters, but propagate more easily across dielectric coatings due to the presence of tangential electric fields. Reversing the polarity of the driving voltage results in the propagation of negative streamers across the patterned dielectric and attenuated effects of catalytic coatings on the streamer dynamics.

Carlos Echeverría-Arrondo, Agustin O. Alvarez, Sofia Masi et al.

Recently, several strategies have been adopted for the cesium lead halide, CsPbX₃ (X = Cl, Br, and/or I), crystal growth with a perovskite-type structure, paving the way for the further development of innovative optoelectronic and photovoltaic applications. The optoelectronic properties of advanced materials are controlled, in principle, by effects of morphology, particle size, structure, and composition, as well as imperfections in these parameters. Herein, we report a detailed investigation, using theoretical and experimental approaches to evaluate the structural, electronic, optical, and electrical properties of CsPbX₃ microcrystals. The microcrystals are synthesized successfully using the hydrothermal method without surfactants. This synthetic approach also offers an easy upscaling for perovskite-related material synthesis from low-cost precursors. Lastly, in this direction, we believe that deeper mechanistic studies, based on the synergy between theory and practice, can guide the discovery and development of new advanced materials with highly tailored properties for applications in optoelectronic devices, as well as other emergent technologies.