bluuebunny/crossref_metadata_2025_split huggingface dataset:
Swing limb detection using a convolutional neural network and a sequential hypothesis test based on foot pressure data during gait initialization in individuals with Parkinson’s disease
Authors: Chan Hsiao-Lung , Chang Ya-Ju , Chien Shih-Hsun , Fang Gia-Hao , Kuo Cheng-Chung , Chen Yi-Tao , Chen Rou-Shayn 
Published: December 2024

Abstract

Objective. Start hesitation is a key issue for individuals with Parkinson’s disease (PD) during gait initiation. Visual cues have proven effective in enhancing gait initiation. When applied to laser-light shoes, swing-limb detection efficiently activates the laser on the side of the stance limb, prompting the opposite swing limb to initiate stepping. Approach. This paper presents the development of two models for this purpose: a convolutional neural network that predicts the swing limb’s side using center of pressure data, and a swing onset detection model based on sequential hypothesis test using foot pressure data. Main results. Our findings demonstrate an accuracy rate of 85.4% in predicting the swing limb’s side, with 82.4% of swing onsets correctly detected within 0.05 s. Significance. This study demonstrates the efficiency of swing-limb detection based on foot pressures. Future research aims to comprehensively assess the impact of this method on improving gait initiation in individuals with PD.
Helicon normal modes in radially non-uniform plasma column
Authors: Guittienne Ph , Karimov R , Jacquier R , Furno I 
Published: December 2024

Abstract
Helicon discharges are often considered somewhat mysterious, exhibiting experimental behaviors that are challenging to explain, such as abrupt plasma density jumps, hysteresis, and ‘blue core’ formation, among others. A significant part of the difficulty in modeling helicon plasmas stems from the limitations of simple analytical approaches that rely on approximations, such as constant plasma density or collisionless plasma, which fail to accurately describe helicon wave physics. We developed a semi-analytical approach to determine helicon normal modes in a collisional plasma column with an arbitrary radial plasma density profile. The influence of radial density profiles on modes propagation, and particularly on their energy deposition patterns, is then investigated. Notably, the study shows that sharp density drops at the plasma column edge lead to edge-localized power deposition, whereas gently varying radial plasma profiles (bell shapes) result in axially peaked power deposition. In the former case, the rapid damping of the Trivelpiece-Gould (TG) component of the wave at the plasma edge is clearly responsible for the observed energy deposition profile. As the profile sharpness decreases, as in bell-shaped plasmas, the TG component of the modes becomes less dominant, and the radial power deposition profile is mainly determined by the Helicon (H) component. Overall, this study of normal modes also demonstrates that dominant H modes are expected to experience much less axial damping than predicted when considering constant densities. Finally, it is also shown that smooth radial density profiles allow a new family of modes to propagate, characterized by long axial wavelengths and slightly off-axis energy deposition patterns.
Resonant-cavity-enhanced Ge/Ge1−
xSnx metal-semiconductor-metal photodetector for 2 μm-band applications
Authors: Kumar Harshvardhan , Sharma Apoorv , Chen Shean-Jen 
Published: December 2024

Abstract
In this work, we propose high-speed and efficient resonant-cavity-enhanced (RCE) Ge/Ge1−x
Sn
x
metal-semiconductor-metal (MSM) photodetectors (PDs) integrated with p-Si interlayer that operate in the 2 um band. Additionally, the p-Si interlayer is employed in the proposed device structure to increase the Schottky barrier height and hence decrease the dark current. With the introduction of a bottom mirror, the Si/SiO2 Distributed-Bragg reflector (DBR) significantly improves the poor absorption of the conventional GeSn MSM PD. Furthermore, in the optical cavity formed by the bottom mirror and SiO2 top mirror, we incorporate an ultrathin i- Ge1−x
Sn
x
active layer. As a result, the proposed RCE PD exhibits exceptionally strong optical fields within the optical cavity as a result of the light resonance. Moreover, this work presents techniques to balance the trade-off between responsivity and the 3 dB bandwidth. Hence, the proposed RCE MSM PD with Ge1−x
Sn
x
(x = 9%) thickness of 25 nm demonstrates outstanding performance at λ = 2 μm, attaining a responsivity of 0.76 A W−1 and a 3 dB bandwidth of 58.1 GHz, all achieved with only two pairs of DBR. These values are significantly higher than the majority of the theoretical values that are currently available. This efficient and fast PD opens up new possibilities for silicon-integrated photonic circuits and their potential applications at 2 um bands.
Deep neural network-based method for designing tunable band gaps metamaterials based on shape memory alloy embedded perforated elastic metamaterials
Authors: Mao Zhuxin , Liu Shutian 
Published: December 2024

Abstract
This paper proposes deep neural networks (DNNs)-based optimization strategy for elastic metamaterials. It aims to attain excellent tunable elastic wave attenuation performance of shape memory alloy (SMA) embedded perforated plates by optimizing the shapes of the SMA inclusions. Firstly, the design of the SMA-embedded perforated plate is presented. By utilizing the property of SMA to phase change between martensite and austenite, a new design for achieving tunable bandgaps is introduced. The finite element method based on the Bloch–Floquet theorem is used to solve the tunable energy band structure, and the effects of geometrical variations of the SMA on the width and position of the tunable bandgap are explored. Next, DNNs is employed to establish the relationship between the geometrical parameters of the SMA and the tunable bandgap. The accuracy of the agent model is verified by performance evaluation. Finally, a strategy combining genetic algorithms and DNNs is proposed for inverse design optimization to obtain metamaterials with superior tunable bandgap performance. The results of five optimization cases demonstrate that the proposed strategy performs well in terms of computational efficiency and real-time design of multiple sets of targets. This study provides an important reference for the development and application of advanced elastic metamaterials with tunable functions.
Origin of the strong anharmonic-induced abnormal thermal conductivity in semiconductors
Authors: Yang Kaike , Liao Fang-Xiu , Zhou Xiao , Zhou Benliang , Zhai Yaxin , He Meng-Dong , Zhou Guanghui , D’Agosta Roberto 
Published: December 2024

Abstract
Semiconducting materials are the foundations of electronics and optoelectronics, and their heat management guides the design of highly efficient devices. For most semiconductors, the thermal conductivity of materials composed of light chemical species is higher than that of the iso-structured materials with heavy elements. For example, bulk Si shows a thermal conductivity higher than Ge. However, for many copper-based compounds, e.g. Cu halides, the thermal conductivity increases monotonously as the atomic number of halogens increases. On the other hand, for lead chalcogenides, the thermal conductivity of PbSe is lower than PbS and PbTe. In this work, we reveal that the combined effect of electronic states coupling and phonon collisions, giving rise to strong anharmonicity, is responsible for the abnormal trend of thermal conductivity of Cu halides and Pb chalcogenides. From CuCl to CuBr and CuI, the increasing thermal conductivity is due to the decreasing electronic coupling strength between Cu-occupied 3d and unoccupied 4s states when crystal symmetry is reduced, which leads to the increase of atomic vibrational potential energy and reduction of lattice anharmonicity. In Pb chalcogenides, the unusually lower thermal conductivity of PbSe than PbTe and PbS is mainly due to the intensive scattering between phonons caused by the localized transverse acoustic modes and soft optical modes, which outweigh the contribution of the crystal anharmonicity due to the anharmonic potential energy surface.
Spin-orbit coupling mediated photon-like resonance for a single atom trapped in a symmetric double well
Authors: Fan Changwei , Hu Xiaoxiao , Yan Xin , Wu Hongzheng , Li Zhiqiang , Xiao Jinpeng , Chen Yajiang , Luo Xiaobing 
Published: December 2024

Abstract
We employ a method involving coherent periodic modulation of Raman laser intensity to induce resonance transitions between energy levels of a spin-orbit coupled atom in a symmetric double-well trap. By integrating photon-assisted tunneling technique with spin–orbit coupling (SOC), we achieve resonance transitions between the predefined energy levels of the atom, thereby enabling further precise control of the atom’s dynamics. We observe that such photon-like resonance can induce a transition from a localized state to atomic Rabi oscillation between two wells, or effectively reduce tunneling as manifested by a quantum beating phenomenon. Moreover, such resonance transitions have the potential to induce spin flipping in a spin-orbit coupled atom. Additionally, the SOC-mediated transition from multiphoton resonance to fundamental resonance and the SOC-induced resonance suppression are also discovered. In these cases, the analytical results of the effective coupling coefficients of the resonance transition derived from a four-level model can account for the entire dynamics, demonstrating surprisingly good agreement with the numerically exact results based on the realistic continuous model.
Reconstruction of electron velocity distribution function and Gibbs entropy from electron cyclotron emission in magnetized plasmas
Authors: Eiichirou Kawamori 
Published: December 2024

Abstract
We propose a method for reconstructing the fluctuation components of the electron velocity distribution function (EVDF), and the electron entropy, which is a functional of the fluctuation components of the EVDF, using the harmonic spectrum from pure X-mode electron cyclotron emission (ECE) in optically thin plasmas. This formulation employs the maximum entropy method in velocity space using the Hankel transform, which converts from v
⊥ space to p space (where, v
⊥ and p are the electron velocity perpendicular to the background magnetic field and the index of the wavenumber in velocity space). Numerical tests validated the effectiveness of the proposed method, which is applicable across a wide range of magnetized plasma conditions, including conditions with both non-relativistic and relativistic electrons, except in cases of harmonic overlap or under optically thick conditions. Notably, this method does not require radiometer calibration for ECE measurements. This method facilitates the experimental evaluation of electron entropy transport in fusion plasma experiments. Moreover, when combined with measurements in k-space (spatial distribution), this approach enables entropy distribution acquisition in phase space (k-p space).
Positive and negative sequence impedance measurement method based on inductance switching for converters
Authors: Wang Jiajia 
Published: December 2024

Abstract
Nowadays, the impedance-based method is a common method to study the small-signal stability of converters. Impedance measurement is the key to using this method. Common impedance measurement methods usually inject disturbances on the primary side and calculate the converter’s impedance by measuring the response excited by the disturbance. The high price and troublesome operation are the drawbacks of this method. In this paper, an impedance measurement method of the grid-tied converters by switching the grid-side inductance is proposed. By changing the grid-side inductance and injecting the same disturbance into the control system before and after the alteration, the positive and negative sequence impedance of the converters can be measured. This paper explains the measurement principle and elaborates the measurement steps. In the end, the effectiveness of the method is verified by simulations.
Neutral-point voltage balancing method for three-phase four-leg three-level ANPC inverter based on modulation waveform splitting
Authors: Zhang Hengkang , Wang Fusheng , Liu Guorui , Wu Wei , Zuo Qingfeng 
Published: December 2024

Abstract
A neutral-point (NP) voltage balancing method based on modulation wave splitting is proposed for a three-phase four-leg (3P4L) three-level (3L) active NP clamped (ANPC) inverter. According to the principle of changing the NP current by adjusting the o-state duty cycle, the NP current injected by each carrier period is made zero by splitting the modulation waveforms of the mid-phase and N-phase. This approach eliminates low-frequency fluctuation in NP voltage under various load conditions. On this basis, according to the inverter operating state and limiting conditions, the output o-state duty cycle of the modulation wave for the intermediate phase and N-phase is adjusted to suppress the NP voltage deviation caused by various non-ideal factors. Finally, the effectiveness of the method is verified through simulation.
Corrosion analysis of switchgear moving contacts in a 66 kV substation of shenyang
Authors: Wang Tianpeng , Xia Yongfeng , Wang Zhongyu , Xiao Shaoyang 
Published: December 2024

Abstract
A serious burn accident occurred in the 10 kV secondary switchgear of a 66 kV substation in Shenyang. The moving contacts of other switchgear that were replaced at the same time showed corrosion and blackening. In order to analyze the causes of the corrosion of the switchgear moving contacts, macroscopic morphology observation, chemical composition analysis, metallographic structure observation, and scanning electron microscopy were utilized. The results indicated that the thickness of the silver plating layer on the contact parts of the switchgear met the standard requirements, and the chemical composition of the spring used for fixing the contacts met the requirements of non-magnetic stainless steel chemical composition. A uniform and continuous corrosion product layer was observed on the outer side, with the presence of sulfur elements detected. The main reason for corrosion was attributed to the presence of a large number of microorganisms and sulfides in the sewage entering the cable tunnel. These elements generated hydrogen sulfide gas under the influence of alienation, which entered the substation along the cable tunnel and reacted with the silver plating layer on the switchgear contacts, resulting in the production of corrosion products such as silver sulfide. This process led to an increase in contact resistance and overheating of the contacts, ultimately causing the burnout of the switchgear.
Research and design of high gain DC-DC converter based on coupled inductor
Authors: Du Fengchen , Xu Song 
Published: December 2024

Abstract
A high-gain DC-DC converter with soft-switching characteristics is proposed to meet the application requirements of new energy transportation and power systems. By using a coupled inductor boost structure and adding a voltage doubling unit, the boost capability of the converter is further enhanced. By constructing a resonant cavity, the switching transistor can operate in ZVS (Zero Voltage Switching), and all diodes can operate in ZCS (Zero Current Switching), significantly reducing device losses. The coupled inductor boost structure can achieve a higher voltage output at a lower switching transistor voltage stress and only requires control by a single switching transistor. The article analyzes a 300W experimental prototype of the converter, which can achieve an efficiency of 90% at a 10-fold voltage gain, verifying the feasibility and superiority of the converter.
32nd IAHR Symposium on Hydraulic Machinery and Systems
Authors: Kumar Arun , Gandhi Bhupendra K 
Published: December 2024

Hydropower is a reliable, versatile, and low-cost source of clean electricity generation and responsible for water management. Hydraulic machinery is an essential component of a hydropower plant to generate electricity. It is always vital to share current knowledge on research and development, including numerical analysis, design, operation, and monitoring of hydraulic machinery and systems. Research and development from academia and industry have constantly been improving the hydraulic turbine and its components design. The IAHR symposium on hydraulic machinery and systems provides unique opportunity to the academic and industrial research teams to exchange the state-of-the-art knowledge and ideas on the development of the next generation of hydropower technology. The 32nd Symposium on Hydraulic Machinery and Systems was jointly organized by the Department of Hydro and Renewable Energy and the Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, India, during September 11 – 14, 2024. This preface describes the overall summary of the symposium, including the plenary & technical sessions, cultural events, and technical tour. The scientific papers reviewed by the expert reviewers, accepted and presented during the symposium are published in a proceeding at IOP Science EES conference series.
List of Introduction, Themes of the symposium, Highlights of the symposium, Keynote Speech, Organizing Committee, Executive Committee, Scientific Committee and Acknowledgement are available in this Pdf.
Chain-reaction collapse of cavitation clouds in Francis turbine runner during start-up
Authors: Mukai T , Nakazono M , Hashidate T , Uchida T , Tezuka K , Matsui J 
Published: December 2024

Abstract
This paper elucidates the hydrodynamic generation mechanism of the extraordinary stress in Francis turbine runner that occurs during start-up, which is called “Hydro Drum”, by unsteady CFD analysis with a cavitation model and model test. The analysis results revealed the pressure wave generated by the collapse of one cavitation cloud caused the collapse of other cavitation clouds. In addition, the magnitude of the pressure wave generated by collapse of the cavitation cloud resulting from the chain-reaction was much larger than that of the cavitation cloud that triggered the chain-reaction, resulting in an impulsive pressure rise. Model tests were conducted to measure the relationship between the extraordinary stress and the pressure on blades, and the mechanism was verified. In conclusion, it is elucidated that the extraordinary stress on runner blades during start-up of a Francis turbines is caused by impulsive pressure rises accompanied by the chain-reaction of collapse of cavitation clouds.
Mitigation of vibrations caused by inter-blade vortices using pumping cap for natural aeration
Authors: Afara S , Nennemann B , Disciullo J 
Published: December 2024

Abstract
In 2014, Andritz received a contract to refurbish six Francis turbines with a total capacity of 840 MW. During the commissioning of the first unit, unexpected vibrations occurred within a power range of 25 to 65 MW, and Andritz was requested to find a solution. Unsteady computational fluid dynamics CFD simulations, revealed that the vibrations originated from intermittently cavitating inter-blade vortices. Conventional solutions involving compressed air injection were rejected, leaving natural aeration as the only viable option. Andritz explored various options for natural aeration by CFD and later, by means of homologous model tests. The solution was able to accommodate suction heads of approximately 10 meters and consisted of a specialized runner cap, referred to as pumping cap, which allowed for natural aeration through the hollow turbine shaft. The cap was optimized using two-phase CFD, and once installed on the prototype, it demonstrated a reduction of aproximately 50% in the peak level of vibration and noise. This achievement fully satisfied the customer, leading to the acceptance of the machine.
Investigation On Various Hard Coating Technologies
Authors: Mack Reiner , Kratzsch Axel 
Published: December 2024

Abstract
For high head hydropower applications, the predominant coating material is 86% tungsten carbide embedded in a cobalt chromium matrix. This material is applied using a high velocity spraying application, which can be powered by either gas or liquid fuels.
This paper outlines the application and wear characteristics for three different scenarios: HVOF (high velocity oxygen fuel) with gas or liquid fuel, and HVAF (high velocity air fuel) with propane as the fuel source. After providing an overview of the distinct technologies and their corresponding application equipment, the discussion delves into the observed coating efficiency during standardized applications with varying coating angles.
To assess the wear resistance of the coatings applied by the different systems, a water jet test rig was developed, that allows the variation of the impingement angle and velocity of the sediment. In the test rig laboratory samples were analyzed against standard sediment with different grain size impacting at predefined angles on the probe. The results clearly demonstrate the superiority of HVAF technology over both HVOF systems. Even at lower coating angles, enhanced wear resistance is evident when utilizing HVAF. Further laboratory investigations on porosity and hardness in the coating support the analysis and the test rig findings.
However, it is worth noting that the deposition rate of HVAF with coating angles smaller than 90° is significant lower compared to the HVOF systems as confirmed by measurements during the application. Consequently, the economic feasibility of the HVAF system is limited to geometries where the coating alignment can be maintained close to perpendicular. Given that the coating system necessitates robotic manipulation, only hydraulic components with sufficient space for the access are suitable for HVAF, while others are more suited to HVOF systems.
Numerical study of flow phenomena and erosion in three guide vane cascade rig
Authors: Shrestha Kushal , Lal Bijukchhe Pawan , Thapa Bhola , Chitrakar Sailesh , Guo Zhiwei , Qian Zhongdong 
Published: December 2024

Abstract
The rivers in certain geological regions like South Asia have sediment particles in them. These particles cause erosion in turbine components which is a major cause of deterioration of turbine and hampers efficient energy production. Out of different modes of erosion in Francis turbines, past studies have shown that erosion is prominent in its guide vanes. Its criticality stems from the ability of eroded guide vane can disturb the flow that reaches the runner and cause erosion in the runner inlet. Numerical study is widely used to study erosion. However, their inability to evolve the geometry with the advent of erosion limits their use. The study uses a three-guide vane cascade geometry, modeled after Jhimruk HPP, to conduct the flow analysis and erosion study. In this study, a RANS-based SST turbulence model has been applied for the flow along with sediments modelled as particles carried by the fluid. The erosion study used the Finnie erosion model to visualize how the erosion occurs in the guide vane. A new framework has been developed that interprets the mathematical values of erosion into the corresponding geometrical changes. Additionally, the study has observed the flow-patterns disruption due to the erosion of the guide vane. This offers a comprehensive overview of the flow in guide vanes cascade and erosion in the guide vanes.