Transmission System Devices Research Articles

From Lab to Life: Self-Powered Sweat Sensors and Their Future in Personal Health Monitoring.

The rapid development of wearable sweat sensors has demonstrated their potential for continuous, non-invasive disease diagnosis and health monitoring. Emerging energy harvesters capable of converting various environmental energy sources-biomechanical, thermal, biochemical, and solar-into electrical energy are revolutionizing power solutions for wearable devices. Based on self-powered technology, the integration of the energy harvesters with wearable sweat sensors can drive the device for biosensing, signal processing, and data transmission. As a result, self-powered sweat sensors are able to operate continuously without external power or charging, greatly facilitating the development of wearable electronics and personalized healthcare. This review focuses on the recent advances in self-powered sweat sensors for personalized healthcare, covering sweat sensors, energy harvesters, energy management, and applications. The review begins with the foundations of wearable sweat sensors, providing an overview of their detection methods, materials, and wearable devices. Then, the working mechanism, structure, and a characteristic of different types of energy harvesters are discussed. The features and challenges of different energy harvesters in energy supply and energy management of sweat sensors are emphasized. The review concludes with a look at the future prospects of self-powered sweat sensors, outlining the trajectory of the field and its potential to flourish.

Modulating nonreciprocal transmission in levitated magnomechanical systems

In this paper, we propose a model of a dual cavity magnomechanical system with two levitated yttrium iron garnet spheres to investigate nonreciprocal transmission of a microwave field. We use an external Coulomb force to bias the steady-state position of the sphere levitated in each microwave cavity, thereby establishing an independent and controllable effective couplings between the cavity modes and the magnon modes. This can break the symmetry of the system and serve as the basis for nonreciprocal transmission in this system. We demonstrated how to achieve the system nonreciprocity with an extremely high isolation ratio and flexible controllability by appropriately selecting the suspended positions of the levitated spheres, which are related to the external bias forces. We also analyze in detail the influence of the cavity detunings and the driving power on the bias-force-induced nonreciprocity. Our study provides an effective approach to manipulating flexibly nonreciprocal transmission of a microwave field and may have potential implications for the development of future nonreciprocal transmission devices.

Electromagnetic performance analysis of a novel radial compound differential field-modulated magnetic gears

Purpose The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation gearboxes. Design/methodology/approach A novel radial differential field-modulated two-stage magnetic gear is introduced, using a unique radial differential linkage to integrate two single-stage magnetic gears. This design incorporates a magnetic isolation ring to enhance transmission efficiency by minimizing magnetic interference and preventing power circulation. The two-stage modulating ring rotor operates synchronously via a connecting bridge, ensuring system stability and efficiency. This configuration not only boosts the gear ratio but also maintains a compact structure, improving power density and efficiency. Leveraging the magnetic field modulation and differential transmission, a finite element model of this gear is developed and its electromagnetic performance is analyzed. Findings The torque density of the new radial differential field-modulated two-stage magnetic gear has increased by 44.97% compared to the traditional tandem two-stage magnetic gear. It achieves a high transmission ratio of 64 and maintains comparable power density, indicating strong torque transfer capabilities suitable for low-speed, high-torque applications. During steady-state operation, the torque pulsation difference between the two stages is minimal, ensuring stable working torque. Social implications This research not only propels the forefront of magnetic gear technology through heightened efficiency and streamlined design but also bears profound societal significance in fostering sustainable energy paradigms. By facilitating superior energy conversion efficiencies in wind turbines and wave energy converters, it plays a pivotal role in mitigating carbon emissions and accelerating the global pivot towards cleaner, renewable energy landscapes. Originality/value A magnetic gear transmission device is proposed, which can achieve high power density and large transmission ratio at the same time, and this study provides a useful reference for the design optimization of new high-performance multistage magnetic gears.

Research progress on transmission performance of special vehicles based on power loss characteristics analysis

The vehicle transmission system is a power transmission device between the engine and the wheel load. As the connecting hub of the power system, the travel system and the braking system, it ensures the mobility and safety of special equipment in combat missions. From the four aspects of the transmission system structure composition characteristics, power transmission characteristics, energy flow characteristics and vehicle power characteristics, it is demonstrated that the transmission efficiency is an important technical indicator for evaluating the performance of the transmission system; based on the analysis of the relationship between power loss and transmission efficiency, a global model framework of the power loss of the transmission system is established from the perspective of the generation mechanism and structural characteristics, providing a theoretical basis for the performance characterization of the transmission system; from the three aspects of theoretical numerical research, simulation research and experimental demonstration research of transmission efficiency, the difficulties and key points of the research on the power loss of the vehicle transmission system are discussed, and it is pointed out that the multi-media and multi-parameter coupling simulation analysis and experimental research of large-scale mechanical equipment under complex operating conditions can provide guidance for the performance optimization and health management of vehicle transmission components, and the performance evaluation and matching design of the transmission system; it is expected that the comprehensive transmission efficiency analysis under multiple factors, as well as the coupling research of power loss characteristics, efficiency characteristics and performance degradation characteristics based on intelligent algorithms have practical engineering significance for the performance monitoring and evaluation of large-scale mechanical equipment.

Bifunctional terahertz metamaterial device with switchable properties between transmission and broadband absorption

A bifunctional terahertz metamaterial device with switchable properties between transmission and broadband absorption is proposed. The simulated results show that the switchable functional characteristics of the bifunctional terahertz metamaterial device can be achieved by taking advantage of the phase transition property of VO2. When VO2 is in the insulating state, there are transmission spectra with a maximum transmittance of 90 % and a minimum transmittance of 25 % in the frequency range from 1 THz to 10 THz. Meanwhile, transmission spectra be adjusted by controlling the Fermi level of graphene. When VO2 is in the fully metal state, the broadband absorptivity achieves over 90 % in the frequency range from 2.54 THz to 7.65 THz. Not only that, the absorption spectra can be continuously adjusted by controlling the conductivity of VO2 from 20 to 200000 S/m. Alternatively, the proposed bifunctional terahertz metamaterial device can work and show the same absorption spectra when the conductivity of VO2 is 200000 S/m under TM and TE polarized normal incidences. Our current research work has a potential to provide a valuable reference for the advancement of transmissive and broadband absorbent metamaterial devices in the terahertz range.

Eigenmode and eigenpropagation of the electromagnetic waves in Möbius and Klein networks

To explore the distribution of characteristic frequencies and the propagation properties of eigenmodes in topological networks at the zero-energy level, we design optical waveguide networks with two typical topologies: Möbius network and Klein network, inspired by the Möbius strip and Klein bottle, respectively. We investigate the degeneracy at characteristic frequencies and the propagation properties of the eigenmodes of these networks, both theoretically and experimentally. We discovered an intriguing eigenpropagation in the Möbius network and multiple degenerate eigenmodes in the Klein network, analyzing the propagation characteristics and distribution patterns of electromagnetic waves within them. In our experiments, we utilize coaxial cables as one-dimensional waveguides to construct transmission line networks for the two networks. We observe the distinct transmission paths of the Möbius network’s eigenmode and the two degenerate eigenmodes of the Klein network. Our findings provide a theoretical foundation for new optical modal transmission devices and novel nanoarrays, with potential implications for theoretical and experimental research in other quantum systems and topological networks.

Automobile Intelligent Vehicle-machine and Human-computer Interaction System based on Big Data

This paper measures the accelerator, brake pedal, clutch, transmission device and steering wheel under different driving conditions in real-time and accurately on the simulation experiment platform. The goal is to conduct human-machine-road system interaction in a virtual simulation of human-vehicle-road systems. Fitting test data establishes the mathematical model of traffic control parameters. In terms of hardware, the distributed architecture of upper and lower computers is utilized. The system communicates point-to-point with the host computer through the RS-232 serial port. The system adopts multi-thread technology and serial communication technology. The simulation system of driving operation is designed with the visual central controller. The system takes 89S52 as the core. The slave program is written in C language. Then, the system establishes a multi-target coordinated obstacle avoidance method based on a multi-sensor information vehicle cooperation collision avoidance method. The multi-vehicle cooperation obstacle avoidance problem is transformed into an optimal control problem under multiple constraints. Simulation analysis shows that the velocity and displacement obtained by the multi-robot collaborative collision avoidance method are in good agreement with the measured values. Compared with the time series algorithm, the output accuracy of the proposed collaborative collision avoidance algorithm is significantly reduced, and the changes in velocity and displacement in the time domain are more stable.

Application of model predictive control scheme for piezoelectric ceramic micro-displacement

Abstract Currently, in the domain of micro-control technology, many operations need to meet the standard of nanometer-level positioning. As a high-precision micro-displacement element, piezoelectric ceramics are widely used in the field of micro-control due to their characteristics such as no need for transmission devices, high resolution, large output force, small size, and fast response speed. However, the inherent hysteresis nonlinearity of piezoelectric ceramics can lead to decreased displacement accuracy, oscillation, and even system instability. Therefore, eliminating the influence of nonlinear characteristics and improving displacement accuracy possess significant practical importance. In this paper, a model predictive control scheme is designed, which achieves faster response speed and higher accuracy compared to traditional control methods such as Proportional Integral Derivative control. Relevant simulations and tests have been conducted. In this scheme, hysteresis nonlinearity is first modeled and then compensated through feedforward, thereby simplifying the displacement control of piezoelectric ceramics into a more manageable linear problem. Subsequently, a linear model predictive control method is adopted to control the entire system. Both simulation and experimental results have verified the effectiveness of this control method.

Multi-objective optimization of helical gear transmission geometric parameters using MOPSO

Abstract Helical gears are widely used in mechanical devices, but insufficient tooth strength can easily lead to premature failure, which is an urgent problem to be solved. To overcome this challenge, this paper introduces a multi-objective particle swarm optimization algorithm, which comprehensively considers the comprehensive effects of modification coefficient, number of teeth, and modulus on the performance of helical gears. By constructing a mathematical model with the geometric parameters of helical gears as the core design variables, aiming to minimize the difference between the maximum bending stress of helical gear roots and the contact stress on the tooth surface, we have achieved optimization of gear performance. Using MATLAB for algorithm programming, the established model was efficiently optimized and solved. After optimization, the bending strength difference and tooth surface bearing capacity of the gear pair have been significantly improved, ensuring the stability and reliability of the operation of the high-pressure sleeve disassembly transmission device.

Analysis of electrothermal shape memory alloy and disc-type magnetorheological fluid combined transmission

In this article, a disc-type magnetorheological fluid and electrothermal shape memory alloy spring-loaded slider friction combined transmission device is proposed. A heating model of the electrothermal shape memory alloy spring is used to calculate the relationship between current and spring temperature. Experiments are used to investigate the link between spring temperature and restoring force, as well as magnetorheological fluid temperature, magnetic flux density, and shear yield stress. The torque characteristics of the combined device were evaluated utilizing the coupled magnetic field and thermal field finite element method for the characteristics of the two materials. The results showed that the magnetorheological fluid showed an approximately linear decrease in shear yield stress at high temperatures, up to 37.94 %. The heating rate of the electrothermal shape memory alloy spring was influenced by the surrounding temperature, and the heating rate was too fast to easily cause the time lag of the martensite phase transformation, resulting in the spring restoring force becoming smaller, and its restoring force shows a non-linear increase when the temperature rises from 22 °C to 100 °C. By applying the two materials together, the torque of the combined transmission has been significantly increased, by 91.58 % compared to the same size magnetorheological transmission.

Backlash size identification for servomechanisms with gear transmission devices

Backlash refers to the spaces between the gear teeth in a transmission device for the purpose of lubrication and accommodating thermal expansion of the gears. This space gets wider with time due to wear on machine components, leading to tracking errors on the load side as well as vibration within the system. If the backlash size can be identified by known information, it can not only be used as an index of a maintenance strategy, but also used in a control scheme to compensate for the effects of the backlash. As a result, this paper proposes an approach for identifying the backlash size using actuator-side information only. In the proposed approach, the timing of a backlash event is determined by a Hilbert-Huang Transform-based method to find the instant in time wherein the actuator side and the load side disengage, while the inertia and friction are identified by a 2-step method. Backlash size can be estimated by integrating the velocity difference between the actuator side and the load side. Experimental results verify the effectiveness of the proposed backlash size estimation method.

Nonlinear damage dynamics modeling and characteristics simulation of bevel gear set

Abstract As a key core device for power transmission in the main reducer of a helicopter, the bevel gear set affects the flight performance of the helicopter directly. A nonlinear damage dynamic model of bevel gear set was constructed using the centralized parameter method. The inherent characteristics and nonlinear behavior characteristics of bevel gear sets were studied, and the time-frequency domain characteristics under different health states were simulated. The fault response transmission law and fault mechanism of the system were deeply revealed, which provides guidance and support for the optimization design of helicopter transmission system and the diagnosis algorithms development.

Design features of a high-pressure transmission devices for hydro-jet technologies

Introduction. Hydro-jet technology is an innovative approach to using high pressure water for a variety of purposes. The technology has found a wide application in various industries, including construction, industry, agriculture and surface cleaning. The basic idea of water jetting systems is to use water as a powerful tool to destroy, clean and cut various materials. The paper discusses the constructing of the high-pressure hydro-puller device for hydro-jet technologies.Materials and methods. An analysis of the methods by hydro-jet technologies classification was made. The general structure and the constituent elements of this scheme is shown. Generalizing elements are identified and a characteristic layout diagram for use in all technological methods of hydro-jet methods is described, and the structural elements that are the main components and units of these technologies are described.Results. The scheme of energy flow on the main nodes of the traditional layout scheme of units for hydro-jet technologies is developed. The energy losses formed in the process of operation are estimated, the element of the hydrojet plant with the largest losses is determined, the peculiarities of its functioning and operation are analysed. The design methodologies, taking into account the identified problems and features, for high-pressure transmitting devices are given.Discussion and conclusions. The most efficient operation of ultra-high pressure transmitting devices for hydro-jet technologies is possible only taking into account their thermal state, characterized by a description of their thermal balance, which can only be ensured through the development of a number of techniques proposed for use in the design of such devices.

Excellent Hole Mobility and Out-of-Plane Piezoelectricity in X-Penta-Graphene (X = Si or Ge) with Poisson's Ratio Inversion.

Recently, the application of two-dimensional (2D) piezoelectric materials has been seriously hindered because most of them possess only in-plane piezoelectricity but lack out-of-plane piezoelectricity. In this work, using first-principles calculation, by atomic substitution of penta-graphene (PG) with tiny out-of-plane piezoelectricity, we design and predict stable 2D X-PG (X = Si or Ge) semiconductors with excellent in-plane and out-of-plane piezoelectricity and extremely high in-plane hole mobility. Among them, Ge-PG exhibits better performance in all aspects with an in-plane strain piezoelectric coefficient d11 = 8.43 pm/V, an out-of-plane strain piezoelectric coefficient d33 = -3.63 pm/V, and in-plane hole mobility μh = 57.33 × 103 cm2 V-1 s-1. By doping Si and Ge atoms, the negative Poisson's ratio of PG approaches zero and reaches a positive value, which is due to the gradual weakening of the structure's mechanical strength. The bandgaps of Si-PG (0.78 eV) and Ge-PG (0.89 eV) are much smaller than that of PG (2.20 eV), by 2.82 and 2.47 times, respectively. This indicates that the substitution of X atoms can regulate the bandgap of PG. Importantly, the physical mechanism of the out-of-plane piezoelectricity of these monolayers is revealed. The super-dipole-moment effect proposed in the previous work is proved to exist in PG and X-PG, i.e., it is proved that their out-of-plane piezoelectric stress coefficient e33 increases with the super-dipole-moment. The e33-induced polarization direction is also consistent with the super-dipole-moment direction. X-PG is predicted to have prominent potential for nanodevices applied as electromechanical coupling systems: wearable, ultra-thin devices; high-speed electronic transmission devices; and so on.

Harnessing a WOx-based flexible transparent memristor synapse with a hafnium oxide layer for neuromorphic computing.

Transparent memristor-based neuromorphic synapses are expected to be specialised devices for high-speed information transmission and processing. The synaptic linearity and potentiation/depression cycles are imperative issues for the application of memristors. This work explores a memristor for improving switching uniformity by introducing a thin HfOx interfacial layer as a diffusion-limiting layer sandwiched between WOx and ITO bottom electrodes. An optimized HfOx thickness not only provides the best switching properties but also shows superior synaptic properties. The optimized 15 nm thin WOx layer can retain the memristor's excellence in P/D linearity, a cycling stability of 494 epochs and image recognition up to 3 mm bending, making it suitable for flexible devices. The artificial synapse is capable of reversible short-term and long-term learning behaviors confirmed by spike-timing-dependent-plasticity (STDP) results. X-ray photoelectron spectroscopy confirms the device composition and provides the oxygen vacancy concentration at the WOx/HfOx interface to realize the switching mechanism. The thicknesses of the different layers are estimated from the high-resolution transmission electron microscopy observations. The fabricated device exhibits 92.2% transparency, as confirmed by the UV-Vis spectrum.

A Review of Nonmultilayer Planar Crossovers: Device for Transmission and Isolation of Multiple Signals in a Planar Configuration

A Review of Nonmultilayer Planar Crossovers: Device for Transmission and Isolation of Multiple Signals in a Planar Configuration

Bioconvective variable viscosity flow of Carreau nanofluid with external heat source and nonlinear radiation: Analysis with convective heat and mass constraints

In this study, an unsteady model for Carreau nanofluid with microorganism decomposition is developed. The viscosity and thermal conductivity of the Carreau nanofluid are considered variable. Magnetic and porosity effects are included using a magneto-porosity parameter. An additional heat source is introduced to improve heat transfer. Nonlinear analysis is applied for radiative applications. The flow is modeled using an oscillatory stretching surface. Convective mass and heat constraints are used to analyze the problem. Analytical computations are performed on the developed model. The significance of various parameters for the thermal problem is discussed. The results may enhance the performance of transport problems, heat transmission, energy systems, and thermal devices.

Assessment of the social effectiveness of providing medical care to patients with a cardiological profile using the method of remote monitoring of blood pressure

BACKGROUND: Assessing social efficiency currently plays a key role in improving the organization of medical care to citizens. Satisfaction with medical care provided is an indicator of the availability of medical care and the effectiveness of healthcare in general. AIM: To assess the social effectiveness of medical care using the method of remote monitoring of blood pressure in cardiac patients based on the results of remote monitoring. MATERIALS AND METHODS: The study materials included data from an anonymous sociological survey of 200 patients who were under dispensary observation and had a history of periods of deterioration in the functional state of the cardiological profile. The questionnaire offered to patients contained six establishing questions, each of which was distributed on a scale balanced from extreme positive to extreme negative assessment. RESULTS AND DISCUSSION: Before conducting remote monitoring, the level of awareness of patients about their own health status, preventive measures, and the use of devices for remote transmission of blood pressure data from the patient to the doctor was investigated. Subsequently, to increase patient awareness, additional information materials on the procedure for interaction be-tween patients and medical workers, as well as about risk factors for the development of cardiovascular diseases and complications from them. The sociological survey was conducted to summarize the results of remote monitoring of patients’ blood pressure and was aimed at studying patients’ opinions on changes in the organization of medical care provided in outpatient settings. CONCLUSION: The data obtained showed that, in general, the degree of achievement of social results after remote blood pressure monitoring increased by 61.0%. Undoubtedly, such an increase in patient satisfaction was achieved as a result of the redistribution of responsibilities between doctors and nurses, as well as a result of well-established participatory interaction between medical workers and patients in terms of remote monitoring of dispensary groups of cardiac patients, instruction in the method of measuring blood pressure and monitoring it indicators in electronic form.

Field appraisal of entomopathogenic fungi horizontal transmission device for entomo-vectoring of Beauveria bassiana and Metarhizium anisopliae in bitter gourd field against Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)

BackgroundBactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) infestation poses a serious risk to bitter gourd cultivation. Traditionally, B. cucurbitae has been controlled using synthetic pesticides, which have drawbacks such as non-target toxicity and pest resistance. Entomopathogenic fungi (EPF) provide concentrated ecological alternatives, which support ongoing pest reduction and sustainable agriculture by adhering to Integrated Pest Management principles. Therefore, EPF provides a viable alternative for chemical control of B. cucurbitae, addressing its shortcomings and promoting environmentally friendly pest control technology. This study evaluated the effectiveness of entomo-vectored horizontal transmission devices (EV-HTD) against B. cucurbitae in bitter gourd fields, focusing on GF-120 and Butanone acetate. Assessment parameters include converting fruit infestation data into yield loss per plant, marketable fruit yield per plant, marketable yield per hectare, and yield loss per hectare.ResultsThe highest mean percentage of entomo-vectored B. cucurbitae (70.50%) was found in plots treated with Butanone acetate + B. bassiana-based EV-HTD. This was followed by GF-120 + B. bassiana-based EV-HTD (66.18%), Butanone acetate + M. anisopliae-based EV-HTD (58.95%), and GF-120 + M. anisopliae-based EV-HTD (54.78%). The Butanone acetate + B. bassiana-based EV-HTD produced the highest mean number of spores per B. cucurbitae (7.80 spores/cm2), while the other treatments produced low spore counts. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest percentage mortality of B. cucurbitae (81.20%). The percentage of fruit infestation varied between 9.00 and 34.00%, with the least amount of infestation seen in plots treated with B. bassiana + Butanone acetate. There were minimal yield losses in Butanone acetate. The Butanone acetate + B. bassiana-based EV-HTD showed the lowest yield losses (66.66 g/plant), while the other treatments showed high losses. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest marketable yield per plant (673.87 g/plant), while yields in control treatments were low. Plots treated with Butanone acetate + B. bassiana-based EV-HTD had the highest marketable yield (2217.85 kg/ha). Lastly, plots treated with Butanone acetate + B. bassiana-based EV-HTD (219.40 kg/ha) showed the lowest yield losses per hectare.ConclusionsAccording to the study’s findings, Butanone acetate-based EV-HTD was more successful than GF-120. Furthermore, B. bassiana was more effective at controlling B. cucurbitae than M. anisopliae. With a maximum cost–benefit ratio of 14.99, the treatment Butanone acetate + B. bassiana was shown to be the most advantageous economically, suggesting its potential for use in practical pest management techniques.

The Prediction of Stability in the Time-Delayed Milling Process of Spiral Bevel Gears Based on an Improved Full-Discretization Method

Spiral bevel gear drives are widely used in mechanical transmission devices due to their compact structure, smooth transmission, and cost-effectiveness. With the continuous improvement in mechanical product quality, higher and higher requirements are set for the precision, smoothness, and power density of gear transmission devices. Chatter can lead to poor workpiece surface finish on spiral bevel gears, excessive tool wear, and even damage to machine tools. Therefore, the effective prediction of milling chatter during the processing of spiral bevel gears is essential. Regenerative chatter is one of the most fundamental types of vibration in machining processes. This paper presents an improved fully discrete algorithm for predicting the stability of time-delayed cutting in the milling process of spiral bevel gears. The method is validated using single- and double-degree-of-freedom models, demonstrating its accuracy and computational efficiency. The results show that the proposed method improves computational efficiency while ensuring accuracy.