bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure scaling laws for partial discharges in wedge-shaped, dielectric-bounded gas gaps
Authors: Färber R , Šefl O , Franck C M 
Published: July 2024

Abstract
A pressure scaling law for the partial discharge inception voltage (PDIV) of wedge-shaped, dielectric-bounded gas gaps is derived and experimentally validated. The investigated prototypical electrode geometry is of relevance in a number of practical applications, such as contacting enameled wires in electric motors or transformers. The derived pressure scaling law is of particular interest for electric propulsion in aviation systems. The results show that the PDIV can be accurately parametrized from first principles as a function of the scaling parameter

p
⋅
s

/

ε
r

, where p is the gas pressure, s is the thickness of the insulating coating and ɛ
r its relative dielectric permittivity. Previously published empirical relationships between the PDIV and pressure are shown to be local approximations of the presented general scaling law. In particular, the often assumed linear relation of PDIV with pressure is shown to not be generally valid.
HTG transformation: an amplitude modulation method and its application in bearing fault diagnosis
Authors: Qiao Xi , Zhang Kun , Zhang Xiangfeng , Zhang Long , Xu Yonggang 
Published: July 2024

Abstract
Rolling bearings are critical components in modern mechanical equipment, and the health monitoring and predictive maintenance of bearings are crucial for the normal operation of machinery. Hence, there is a compelling need to delve into advanced methodologies for enhancing the detection of fault characteristics in bearings. Faulty bearings produce periodic impulses during constant-speed rotation, which can typically be detected through envelope analysis. However, in some complex conditions, the relevant fault frequencies may be hidden within interfering components. This paper presents an amplitude modulation technique called the hyperbolic tangent Gaussian (HTG) transformation, designed to extract weak fault components from signals. Firstly, a family of amplitude modulation functions, known as the HTG functions, is constructed. These functions modulate signals with normalized amplitudes to obtain a series of modulated signals. Simultaneously, a frequency domain amplitude ratio metric is used for the automatic selection of the optimal components. Finally, the HTGgram is introduced, a spectral decomposition method based on trend components, aiming to identify the best combination of filtering and modulation components. Simulations with multi-component bearing fault signals and experimental signals with composite bearing faults demonstrate that this method not only highlights fault features and suppresses noise interference but also adaptively selects frequency bands related to faults, enhancing fault information. This approach exhibits excellent adaptability and effectiveness in complex operating conditions with multiple interference components.
Ozone production by an He+O2 radio-frequency atmospheric pressure plasma jet driven by tailored voltage waveforms
Authors: Harris Benjamin , Dedrick James P , Niemi Kari , Wagenaars Erik 
Published: July 2024

Abstract
Atmospheric pressure plasma jets are efficient sources of reactive oxygen and nitrogen species with potential applications in medicine, materials processing, green industry and agriculture. However, selective control over the production of reactive species presents an ongoing challenge and a barrier to the widespread uptake of these devices in applications. This study therefore investigates the production of ozone by a radio-frequency plasma jet driven with tailored voltage waveforms composed of up to five consecutive harmonics, with a fundamental frequency of 13.56 MHz. The plasma is supplied with helium with small admixtures (0.1%–1.0%) of oxygen gas. The ozone density in the far effluent is measured with Fourier transform infrared spectroscopy and the gas temperature in the plasma channel is determined with optical emission spectroscopy. Voltage waveform tailoring is found to enhance the ozone density in the far effluent of the plasma jet in comparison to operation with single-frequency voltage waveforms. Increasing the number of applied harmonics in the driving voltage waveform for a fixed peak-to-peak voltage enhances the ozone density but significantly increases the gas temperature within the plasma channel. Meanwhile, increasing the number of applied harmonics while maintaining a constant RF power deposition allows the density of ozone in the effluent to be increased by up to a factor of 4 relative to single-frequency operation, up to a maximum density of 5.7

×

10

14

cm−3, without any significant change to the gas temperature. This work highlights that tailored voltage waveforms can be used to control the density of ozone delivered through the plasma effluent, marking an important step towards realising the potential of these plasmas for applications.
Gravitational wave signatures of a chiral fermion dark matter model
Authors: Abe Tomohiro , Babu K.S. , Kaladharan Ajay 
Published: July 2024

Abstract
Theories in which the dark matter (DM) candidate is a fermion transforming chirally under a gauge symmetry are attractive, as the gauge symmetry would protect the DM mass. In such theories, the universe would have undergone a phase transition at early times that generated the DM mass upon spontaneous breaking of the gauge symmetry. In this paper, we explore the gravitational wave signals of a simple such theory based on an SU(2)D dark sector with a dark isospin-3/2 fermion serving as the DM candidate. This is arguably the simplest chiral theory possible. The scalar sector consists of a dark isospin-3 multiple, which breaks the SU(2)D gauge symmetry and also generates the DM mass. We construct the full thermal potential of the model and identify regions of parameter space which lead to detectable gravitational wave signals, arising from a strong first-order SU(2)D phase transition, in various planned space-based interferometers, while also being consistent with dark matter relic abundance. The bulk of the parameter space exhibiting detectable gravitational wave signals in the model also has large WIMP-nucleon scattering cross sections, ℴSI, which could be probed in upcoming direct detection experiments.
A novel semiquantum key distribution protocol with Bell states
Authors: Sun Zhenying 
Published: July 2024

Abstract
In this paper, a novel semiquantum key distribution (SQKD) protocol is proposed using Bell states, where quantum Alice can share

N

secret bits with semiquantum Bob via a quantum channel. Semiquantum Bob is required to measure particles with the

Z

basis (i.e.

{

|
0
⟩

,

|
1
⟩

}

), produce fresh particles within the

Z

basis and send particles via a quantum channel. Security analysis turns out that this protocol is immune to various attacks launched by the outside eavesdropper. Compared with present SQKD protocols using Bell states without a third party (Sun et al 2011 arXiv:1106.2910v3; Wang et al 2011 Chin. Phys. Lett.
28 100301; Wu et al 2022 Front. Phys. 10 1029262), on the one hand, this protocol has the highest qubit efficiency; and, on the other hand, the reflecting operations of the semiquantum user in this protocol contribute to the generation of final shared keys.
Overview of research status and key technologies of bionic flapping wing aircraft
Authors: Yuan Li , Yubo Zhang 
Published: July 2024

Abstract
The design of bionic flapping-wing aircraft, drawing inspiration from birds and insects’ aerodynamic traits and flapping patterns, exhibits distinct advantages at low Reynolds numbers—a limitation of conventional fixed-wing and rotorcraft. Hummingbirds, renowned for their hovering, forward, and backward flight capabilities, inspire military and other applications seeking both performance and concealment. This paper summarizes research progress and key technologies in bionic flapping-wing aircraft, focusing on bird flight mechanisms and the design of hummingbird-mimicking aircraft. Key mechanisms like delayed stall, added mass effect, and wake capture are highlighted. The paper also outlines design considerations and identifies key bottlenecks and future trends in this exciting field.
Linked multidisciplinary optimisation of a twin-shaft turbine of a promising turboshaft engine
Authors: Popov G M , Zubanov V M , Baturin O V , Scherban A I 
Published: July 2024

Abstract
The paper presents the results of the linked multidisciplinary optimisation of a single-stage turbine of a compressor and a single-stage free turbine of a promising turboshaft engine. In the process of optimisation, gas dynamic, strength, design and technological constraints were taken into account. Calculation of gas dynamic parameters was performed using 3D CFD modelling. Calculation of strength parameters was performed using 3D CSM modelling. Analysis of geometrical parameters of blade profiles was performed using in-house developed programmes. The geometrical parameters of the blade profiles were used as varied parameters. The total number of varying parameters was 194. As a result of solving the optimisation task, a turbine variant was found with the compressor turbine efficiency 0.32 % higher than that of the original turbine, as well as with the efficiency of the free turbine 0.7 % higher than that of the original one. At the same time the fulfilment of all constraints is ensured.
LAVIT (LAVavatory system for Interplanetary Travels) for NASA’s Artemis Program
Authors: Karmakar Riya , Shastri Bhardwaj , Choomjinda Ubol , Mukundan Arvind , Wang Hsiang-Chen 
Published: July 2024

Abstract
NASA’s Artemis program aims to land on the Moon by 2024. Returning to the Moon will establish a base for future crewed Mars missions. Many efforts are underway to provide astronauts with equipment, housing, and other assistance as the prospect of returning to the Moon. Mass reduction, volume reduction, energy efficiency improvements, and operational optimization are the goals. Astronauts will urinate and defecate in microgravity and lunar gravity after eating and drinking. During their time inside the spacecraft and outside of their spacesuits, astronauts will require a toilet that possesses equivalent functionalities to that found on Earth. Therefore in this study, a complete lavavatory system for interplanetary travels have been developed and designed.
Image Matching-Based Visual-Inertial Integrated Navigation for UAV in GNSS-Denied Environments
Authors: Huang Tianqi , Zhou Yibiao , Zhang Bihui 
Published: July 2024

Abstract
For unmanned aerial vehicle (UAV) navigation in global satellite navigation system (GNSS)-denied environments, an image matching-based visual-inertial integrated navigation system is proposed. Deep learning-based methods are used for image matching to address the challenges of multi-modal image matching. A feature mismatch removal method using reference visual data and inertial navigation prior pose is proposed to improve the accuracy and robustness of image matching. Error-state Kalman filtering (ESKF) is applied to fuse the outputs of visual navigation and inertial navigation and calibrate the inertial navigation system. In addition, an image mismatch detection method based on Kalman innovation detection is applied to avoid severe errors caused by image mismatch. Finally, the proposed integrated navigation system is validated by Airsim simulation and a public dataset.
The stiffness of elastomeric diaphragm in pneumatic springs
Authors: Bai Yumei , Che Jixing , Wu Mingkai , Wu Jiulin , Jiang Wei 
Published: July 2024

Abstract
The design of pneumatic springs applied in precision vibration isolation platforms requires an accurate mathematical model. Many validation experiments have shown that neglecting the effect of the diaphragm on the response of a isolator can lead to a significant error between the observed and predicted behavior. This paper modifies the standard pneumatic spring model by considering the effects of the diaphragm on stiffness. A theoretical model for diaphragm stiffness is presented. The model equates the inner and outer rings of the diaphragm into two segments of composite material subjected to unidirectional stretching. The elastic modulus and stiffness of each part of anisotropic materials were obtained using the theory of composite mechanics, combined with the working conditions of the diaphragm. Finally, the dynamic stiffness experimental platform was built to verify theoretical model. The result indicates that considering the stiffness of elastomeric diaphragm, the error is reduced from 27.33% to 7.5%.
Development and Application of the Sliding Plane Method for Turbomachinery
Authors: Zhou Yeqi , Fu Jue , Ye Zhouteng , Sun Wei , Cui Jiahuan 
Published: July 2024

Abstract
This study focuses on the development and application of the sliding plane method for turbomachinery. The implementation of sliding plane consists of two parts: (1) grid manipulation in pre-processor and (2) sliding mesh interpolation in solver. In pre-processor phase, mesh extrusion, donor-receptor search pairing, and geometric array updates algorithms are implemented. Based on the updated grid information in pre-processor phase, flux interpolation between pairwise sliding planes is developed for unsteady Raynolds-averaged simulation (RANS). To validate the performance of our sliding plane method, the comparative simulation with the mixing plane method on Transonic Compressor Darmstadt (TCD) at Technical University of Darmstadt (TUDa) case is conducted using both sliding boundary and hybrid boundary methods. Special concern is placed on the stall phenomena near the leading edge of the compressor under near-stall conditions. Numerical results show superior agreement with experimental data compared to the mixing plane results, affirming its effectiveness in simulating unsteady conditions.
Development of Large-scale Bending and Torsional Test Rig Using Strong Floor Anchorage System for Structural Analysis
Authors: Abdul Hamid M F , Yob M S , Vishnu J S , Izahar M M 
Published: July 2024

Abstract
The common practice among researchers is to use scaled models for validation. However, using scaled models can lead to errors due to the scaled factor. To overcome this problem, this paper presents the development of a large-scale bending and torsional test rig for structural analysis which is involves testing the actual scaled model of the structure. In this research, a portal frame powered by a hydraulic system anchored to a strong floor is developed to evaluate specimens’ sizes up to 6 m x 2 m, such as planar frame and space frame structures. The design of the strong floor and the test rig will be analyzed for three-point bending, four-point bending and torsional tests. For stress analysis, it was found that the design of the test rig is capable of carrying out three-point bending test up to 37.6 kN, four-point bending test up to 75.2 kN, and torsional testing up to 4.1 kN.
Research Status and Development Trend of Precision Cutting Technology
Authors: Shan Li  , Calderon Aldrin D. 
Published: July 2024

Abstract
Precision cutting technology plays an important role in modern manufacturing, which providing key solutions for the production of high-precision, high-quality parts. Firstly, on the basis of reading a lot of relevant papers, the classification of precision cutting technology are summarized in this paper, and then the research status of cutting force control, tool wear, nano cutting, model simulation and optimization and green sustainable development are summarized and analyzed. On this basis, the problems existing in the current precision cutting technology are pointed out, and the future development trend is predicted.
Pneumatically Operated Tendril-based Soft Hyper-Redundant Robotic Gripper
Authors: Sanyal Shubhashis , Kumar Shukla Anuj , Sharad Pinjan Hrishi , Tailor Piyush , Pavan Kumar Pyla , Saurav Suman , Kumar Bhargav Surjeet 
Published: July 2024

Abstract
The present work aims to design a soft, hyper redundant robotic gripper inspired by natural tendrils. The development of automation also requires extensive study in the field of biomimetic robotics. Most robotic systems are generally built using traditional rigid materials, such as hard plastics and metals. Creating accurate robotic systems necessitates the assembly of firm components connected at specific joints. Nonetheless, crafting a robotic system modeled after natural systems, comprising continuous deformable materials, is anticipated to match or exceed the capabilities of rigid robotic systems. Soft and highly redundant robotic grippers offer nearly limitless degrees of freedom (DOF) and elevated levels of kinematic redundancy. In the present work, a soft robotic gripper is proposed, inspired by plant tendrils that deform helically to hold the object on actuation. The work describes the initial design, material selection, method, important design parameters, an actuation mechanism and the simulation and analysis of the soft gripper. Such studies will be useful to industries and researchers in automation and biomimetic robotic systems.
Explicit Calculation Method for Heat Exchanger Considering Variable Physical Property Treatment
Authors: Liu Z W , Liu Q H , Wen J , Dong B S 
Published: July 2024

AbstractThis work presents a heat exchanger calculation method characterized by the explicit temperature solution (ETS) for the working medium. This method is derived for both parallel-flow and counter-flow patterns based on the traditional LMTD method. As the temperature distribution is given in an explicit form related to the mixing temperature, the heat transfer performance of heat exchangers can be solved without iterations, improving the efficiency of heat exchanger design. Considering the practical engineering application, the influence of variable physical property is discussed. The temperature distributions of the reference temperature method and the integral method (whole length) are compared with the accurate distribution of the adaptive-grid method (segmented). Results indicate that the temperature distribution obtained by the integral method highly coincides with the accurate one, showing a relative error of only 0.36 %. The proposed ETS method with integral physical property treatment is an efficient and accurate way for heat exchanger design.
Industrial Air Purifiers: CFD Investigation for Optimized Duct Design for Noise Reduction and Performance Enhancement
Authors: Kumar Shukla Anuj , Babu Dinesh , Dubey Sameer 
Published: July 2024

Abstract
This research investigates into the critical intersection of fluid dynamics and noise generation within industrial air purifier ducts. As industrialization escalates, so does the concern for environmental challenges and air pollution. Industrial air purifiers, designed to combat airborne contaminants, play a pivotal role in fostering cleaner and healthier industrial environments. However, the accompanying noise from essential components poses challenges for worker well-being and operational efficiency. Utilizing Computational Fluid Dynamics (CFD) simulations, our investigation systematically explores the impact of duct geometry on fluid dynamics, turbulence, and noise generation. Validation against experimental data ensures the accuracy of our numerical model. The deliberate variations in duct design across five models, coupled with subsequent simulations for four additional designs, reveal Design 5 as a successful contender in achieving noise reduction objectives. Comparative analyses of outlet velocities, inlet pressures, and sound levels provide actionable insights for engineers and manufacturers. This research not only advances our understanding of duct geometry’s role in noise generation but also paves the way for quieter and more efficient industrial air purifiers. The optimized designs contribute to creating industrial environments that prioritize both workplace well-being and environmental sustainability.
Investigation of the weight effect on the oscillations of a magnetically-levitated body coupled to an energy harvester
Authors: Francis A C , Kandil A , ElSaid A , Zahra W K 
Published: July 2024

Abstract
Energy harvesting technology utilizes magnetic oscillations to produce electrical energy which in turn powers any small device. This paper discusses the numerical analysis of a non-ideal magnetic levitation system, with emphasis on the energy harvesting potential considering the weight of the oscillating middle block. The system being considered is a magnetic levitation system connected to an electrodynamic shaker that excites the base of the system to produce oscillations. The outcome of modelling the Maglev system is a coupled highly nonlinear equation that resembles the duffing oscillator. Runge-Kutta method is carried out to describe the temporal behavior of the oscillatory middle block and hence the harvested power. The results of findings presented through phase planes, Poincare map and parametric variations indicate that varying parameters such as Ω and E, directly impact power harvesting and system stability. This paper explores periodic and non-periodic motions in the temporal behavior of the Maglev system, contributing to the current trend in energy harvesting. The novel addition of the middle block’s weight offers crucial insights for enhancing energy harvesting devices, paving the way for future advancements in system design and application.
Heating opaque material sheets by a blue laser
Authors: Sibsiri Kwanruthai , Kijamnajsuk Puchong , Sutthiopad Malee , Luengviriya Chaiya 
Published: July 2024

Abstract
We present a study of heating small opaque substrates using a blue laser diode. It can be used as a method of temperature control for small sensors, e.g., atomic magnetometers. A blue laser from a low-cost engraving machine is used to illuminate an opaque material sheet (1×1×0.2 cm3) attached to a 1-cm glass cuvette whose size is similar to a typical vapor cell in compact atomic magnetometers. The input electric power of the laser diode (P) is supplied by a laser driver board and controlled via a computer by a pulse width modulation. We investigate the heating method using the electric power (P) between 2.67 and 4.67 W and 4 types of opaque materials: a silica bonded investment material, a gypsum bonded investment material, a silicone epoxy, and a mortar. The results show that in all cases, the temperature of the cuvette increases with time until it reaches a maximum value (Tmax) within 10 mins. For all tested materials, Tmax always increases with the power P. For a given power P, Tmax depends on the material type. At the maximum power of 4.67 W, Tmax are 52°C, 64°C, 81°C, and 88°C for the silica bonded investment material, the gypsum bonded investment material, the silicone epoxy, and the mortar, respectively. Therefore, among the tested materials, mortar is the most effective material for laser heating.
Multi-objective optimal design for the railway bogie frame system under stress and fatigue analysis
Authors: Lee Cheng-Kang , Liu Chien-Kuan , Cheng Yung-Chang 
Published: July 2024

Abstract
This work focuses on applying a novel and integrated multi-objective optimization approach to enhance the strength of the railway bogie frame system under both static loads and fatigue tests. The finite element modelling is conducted using ANSYS/Workbench software, and the von Mises stress and fatigue safety factor of the bogie frame are computed through conventional simulations for EN 13749 and EN 15663 testing. After employing the uniform design method, the fatigue safety factor is increased from 1.924 to 2.586, resulting in a 34.41% improvement rate for the bogie frame. Additionally, the von Mises stress is reduced from 56.96 MPa to 42.91 MPa, reflecting a 24.66% improvement rate compared to the original design. Following the implementation of the multi-objective optimum design process, the fatigue safety factor further improves from 1.924 to 2.742, resulting in a 42.51% enhancement for the bogie frame. Simultaneously, the von Mises stress decreases from 56.96 MPa to 40.48 MPa, yielding an improvement rate of 28.92%.