bluuebunny/crossref_metadata_2025 huggingface dataset:
Exercise Types and the Risk of Developing Cognitive Decline in Older Women: A Prospective Study
Authors: Osuka Yosuke , Kojima Narumi , Sasai Hiroyuki , Ohara Yuki , Watanabe Yutaka , Hirano Hirohiko , Kim Hunkyung
Published: September 2020

Background: Participation in exercise may be useful for dementia prevention; however, the specific exercise types which may best to reduce the risk of developing cognitive decline have remained unidentified in the literature. Objective: To examine the relationships of specific exercise types with the risk of developing cognitive decline in older women. Methods: This 1- to 2-year population-based cohort study included 687 community-dwelling older Japanese women without disability, neurological disease, dementia, or cognitive impairment assessed as <24 points on the Mini-Mental State Examination (MMSE) at the baseline survey. Developing cognitive decline was defined as a decrease of ≥3 points in the participant’s MMSE score during the follow-up. We classified individuals into participation (≥3 months) and non-participation (<3 months) groups for 17 different exercise types. Log-binominal regression analyses were applied to compare risk ratios and confidence intervals of developing cognitive decline between the two groups. Results: Thirty-nine participants (5.7%) developed cognitive decline during the follow-up period. After adjusting for confounders (age, MMSE score, depressive symptoms, body mass index, heart disease, hypertension, diabetes, smoking, low educational level, and the follow-up period in the baseline survey), those who participated in calisthenics demonstrated a significantly lower risk of developing cognitive decline than those who did not participate in calisthenics. No significant relationships between other exercise types and the risk of developing cognitive decline were found. Conclusion: Participation in calisthenics significantly reduced the risk of cognitive decline in community-dwelling older Japanese women, indicating that calisthenics may be a useful type of exercise for promoting dementia prevention.
Optimal design of a surface-mounted permanent magnet motor with multi-grade ferrite magnets to reduce torque pulsations
Authors: Liu Yan , Zhao Wenliang , Fan Xue , Wang Xiuhe , Kwon Byung-il
Published: September 2020

This paper proposes an optimal design for a surface-mounted permanent magnet motor (SPMM) to reduce torque pulsations, including cogging torque and torque ripple, by using multi-grade ferrite magnets. Based on a conventional SPMM with single-grade ferrite magnets, the proposed SPMM is designed with four-grade ferrite magnets and then optimized to minimize torque pulsations by maintaining the required torque, utilizing the Kriging method and a genetic algorithm. The results obtained by the finite element analysis show that the optimized SPMM with multi-grade ferrite magnets exhibits improved airgap flux density distribution with highly reduced cogging torque and torque ripple by maintaining the same average torque, as compared to the conventional SPMM. Furthermore, the analysis of the working points for the multi-grade ferrite magnets reveals that the optimized SPMM has good durability against the irreversible demagnetization.
Comparative study of the reluctance machines with and without field winding for generator and starter applications
Authors: An Junhao , Shi Liwei , Han Zhen , Tan Di
Published: September 2020

The switched reluctance starter generator (SRSG) without field winding and the doubly salient electromagnetic starter generator (DSESG) with field winding are compared in this paper. The influences of two arrangements of each variable winding and spacing variable winding for the performance of the starter generator were studied. Mathematical models of start mode and power generation mode were established respectively, and the influencing factors of starting torque and power generation phase voltage were derived. Next, the finite element simulation software was used to simulate the electromagnetic characteristics of machine. Finally, prototype experiment was made. The finite element simulation and prototype experiment results proved that spacing excitation DSESG has a better prospect as automotive starter generator.
Experimental verification of improved probability of detection model considering the effect of sensor’s location on low frequency electromagnetic monitoring signals
Authors: Song Haicheng , Yusa Noritaka
Published: September 2020

Structural health monitoring (SHM) is a promising method for maintaining the integrity of structures. A reasonable approach is necessary to quantify its detection uncertainty by taking into account the effect of random sensor locations on inspection signals. Recent studies of the authors proposed a model that adopts Monte Carlo simulation to numerically obtain the distribution of inspection signals influenced by random sensor locations. This model can evaluate the effect not only of multiple defect dimensions but also of the placement of sensors on the detection uncertainty. However, its effectiveness has only been confirmed using pseudo-experimental signals generated by artificial pollution. This study aims to examine the effectiveness of the proposed model in quantifying the detection uncertainty of SHM methods using the experimental signals of low frequency electromagnetic monitoring for inspecting wall thinning in pipes. The results confirm the capability of the proposed model to correctly characterize the distribution of inspection signals affected by random sensor locations and to determine the reasonable probability of detection.
Simply supported FPEDs connected by springs for broadband energy harvesting
Authors: Tanaka Yoshikazu , Odake Satoru , Miyake Jun , Mutsuda Hidemi , Popov Atanas A. , Patel Rupesh , McWilliam Stewart
Published: September 2020

Energy harvesting methods that use functional materials have attracted interest because they can take advantage of an abundant but underutilized energy source. Most vibration energy harvester designs operate most effectively around their resonant frequency. However, in practice, the frequency band for ambient vibrational energy is typically broad. The development of technologies for broadband energy harvesting is therefore desirable. The authors previously proposed an energy harvester, called a flexible piezoelectric device (FPED), that consists of a piezoelectric film (polyvinylidene difluoride) and a soft material, such as silicon rubber or polyethylene terephthalate. The authors also proposed a system based on FPEDs for broadband energy harvesting. The system consisted of cantilevered FPEDs, with each FPED connected via a spring. Simply supported FPEDs also have potential for broadband energy harvesting, and here, a theoretical evaluation method is proposed for such a system. Experiments are conducted to validate the derived model.
Analysis of eddy current field for new type of thrust bearings based on single-objective genetic algorithm
Authors: Ling Xiao , Xiwu He , Wenjie Cheng
Published: September 2020

Based on the working condition of the magnetic thrust bearing (MTB), the single-objective optimization model (SOOM) is built. The optimum design of structure parameters for two types of magnetic bearings including traditional carbon bearing and soft magnetic composite (SMCs) bearing has been carried out using genetic algorithm. The analysis of eddy current field for two types of bearings are obtained by FEM. It is found that the maximum eddy current field of SMCs bearing is less than that of carbon steel one, and the air gap magnetic density is larger than that of carbon steel bearing at the same frequency. SMCs obtained by the compression of insulated soft magnetic powders have low eddy current. Thus, under the same magnetic force conditions, the input current of SMCs bearings is lower than that of carbon steel ones. The analysis shows that SMCs can replace carbon steel and has superiority in bearing application.
Non-resonant response of the novel airborne photoelectric quasi-zero stiffness platform with friction damping
Authors: Dong Guangxu , Ma Chicheng , Zhang Feng , Luo Yajun , Bi Chuanxing
Published: September 2020

To suppress the low frequency vibrations of airborne photoelectric system and improve measurement accuracy, a novel passive airborne photoelectric quasi-zero stiffness platform (APQZSP), which is composed of upper/bottom planes, anti-shaking structure and six quasi-zero stiffness (QZS) legs, is designed. The QZS leg is constructed by connecting the folded beam spring with magnetic negative stiffness spring (MNSS) in parallel. According to current model, the magnetic force and negative stiffness of MNSS are derived. As the friction damping is introduced with anti-shaking structure, the isolation performance of the platform under friction damping is investigated based on harmonic balance method. Then the effect of damping and excitation on the isolation performance is analyzed. The results indicate that with the QZS technology, the resonant frequency of the platform is reduced and the low frequency vibrations can be effectively isolated with APQZSP. Moreover, the friction damping can maintain the displacement transmissibility at unity as long as the excitation frequency is lower than the break-loose frequency, and then the resonance can be avoided.
Online identification of impact loads of multi-degree-of-freedom system based on Kalman filter
Authors: Jiang Jinhui , Luo Shuyi , Liang Zhongzai
Published: September 2020

Dynamic load identification is the second kind of inverse problem in structural dynamics. It is a process of reconstructing load applied to structure in case of structural dynamic model and information of structural response. Online identification is one of the frontier problems in dynamic load identification, which has high difficulty and broad application prospects. In this paper, an online identification of dynamic load of the multi-degree-of-freedom system based on Kalman filter in modal space is proposed. Since the Kalman filter has excellent real-time performance and robustness, it is possible to be used in dynamic load online identification. We start from the theoretical derivation in detail for the multi-degree-of-freedom system, then the feasibility and effectiveness of the method is verified by numerical simulation of three-degree-of-freedom system with the single impact load and continuous multiple impact load.
Investigation of a shape memory alloy releasable mechanism applied in space environment
Authors: Bian Kan , Zhou Chunhua , Zhao Fagang , Wu Yipeng , Xiong Ke
Published: September 2020

Though the conventional pyrotechnic fastener mechanisms are widely used in spacecraft for their reliable releasable-fastening function, they still have several unavoidable problems: physical shock, high maintenance cost, to name a few. This paper introduces a new type of smart releasable mechanism based on a Shape Memory Alloy (SMA) spring and its corresponding heating apparatus. To obtain the high heating efficiency and increase the response speed, the SMA spring is transitionally fit with the heating apparatus shell instead of directly heating by electric current. As soon as the heating apparatus begins to work, the SMA spring will provide an un-locking force to release the fastening device within the standard time, which also realizes the similar releasable-fastening function comparing with the conventional pyrotechnic fastener mechanisms. In order to ensure the reliability of space products, the heating apparatus is composed of two identical ceramic heating elements which can be controlled independently or synchronously. Finally, the experimental results clearly show that, under the satellite power supply at the constant value of 28 V, the SMA spring can reach the desired 30 N unlocking force within 93 s and 51 s by single or dual heating elements, respectively. The maximal output force can even be increased as large as 40 N under the limited volume of the releasable mechanism.
Nonlinear vibration control of nano-beam based on capacitive acoustic sensors
Authors: Wan Lei , Liu Canchang , Kong Weixu , Zhou Yingchao , Ma Chicheng
Published: September 2020

The nonlinear vibration control of the Euler–Bernoulli beam is studied based on capacitive micro-mechanical acoustic sensors The graphene film has the characteristics of high sensitivity and high accuracy which can be applied to sense the vibration signal. Capacitive micro-mechanical acoustic sensors can be used to detect the acoustic signal of the vibration of the nano-beam. The nonlinear vibration control equation of nano-beam can be established with the displacement and velocity voltage feedback controller based on capacitive micro-mechanical acoustic sensors. The amplitude-frequency response equation of the primary resonance of nano-beam can be gotten by using the multiple scales method. The relationship between the nonlinear vibration of nano-beam and system parameters is investigated. The influencing factors of how to weak system nonlinearity and enhance system stability are analyzed. The static bifurcation behavior of the system is discussed. The numerical results show that the nonlinearity of vibration can be reduced and the stability of the system can be improved by selecting the appropriate control gains and appropriately reducing the amplitude of DC and AC excitation voltages.
Analysis of magneto rheological elastomers for energy harvesting systems
Authors: Diguet Gildas , Sebald Gael , Nakano Masami , Lallart Mickaël , Cavaillé Jean-Yves
Published: September 2020

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.
Research on active vibration control of flexible wing based on MFC actuator
Authors: Luo Yajun , Yang Fengfan , Ji Linwei , Zhang Yahong , Xu Minglong , Zhang Xinong
Published: September 2020

An active vibration control scheme was proposed based on Macro Fiber Composite (MFC) actuators for the bending and torsional vibration control of large flexible lightweight wing structures. Firstly, a finite element modeling and modal analysis of a flexible wing are carried out. Further, the number, type, and location distribution of the MFC actuators bonded on the supported beam of the wing are designed. Then, the actuated characteristics of the two kinds of MFC actuators required for bending and torsional vibration controls was theoretically analyzed. The simulation model of the overall vibration control system was also finally obtained. Finally, through ANSYS simulation analysis, the vibration control effect of the current control system on the first two-order low-frequency modal response of the wing structure is given. The simulation results show that the proposed active vibration control scheme has specific feasibility and effectiveness.
A study on influence of strong magnetic field on fracture of interface crack considering magneto-elastic coupling effects
Authors: Xie Zheng , Zhao Yinsong , Li Qun , Chen Zhenmao , Uchimoto Tetsuya , Takagi Toshiyuki
Published: September 2020

The influence of strong magnetic field on stress intensity factor of an interface crack is studied in this paper. The nonlinear piezomagnetic property and magnetostriction effect have been taken into consideration in the theoretical analyses. This multi-field coupled problem is solved through a sequential coupling approach. The perturbed magnetization caused by the deformation around the crack is solved under magnetic boundary conditions. After modified by the perturbed magnetization, the initial loads are updated with magnetic forces for iterative calculation. With this strategy, the distributions of the stress and displacement at the crack region approach to the real solution gradually. Numerical results show that the influence of the external magnetic field on fracture behaviors is not ignorable. For structures with interface crack serving in a strong magnetic field, e.g., the multi-layer welded structures in the Tokamak device, the magneto-elastic coupling effects have to be considered to deal with its fracture problem.
Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element
Authors: Zhao Yingsong , Jomdecha Cherdpong , Xie Shejuan , Chen Zhenmao , Qi Pan , Liao Shusheng , Uchimoto Tetsuya , Takagi Toshiyuki
Published: September 2020

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.
Investigation on the traveling wave and three-dimensional trajectory of motion on the stator of rotational ultrasonic motors
Authors: Chen Hucheng , Han Wei , Qiu Jinhao
Published: September 2020

Better understanding of the characteristics of the traveling wave and three-dimensional trajectory related to motion on the surface of the stator is very important for the design and performance improvement of the ultrasonic motors. In this paper, an accurate finite element model of a single stator with a fully coupled piezoelectric layer was established at a moderate computational cost. The finite element model was verified by experimental test at the inverse resonance point. Based on this model, the traveling wave and three-dimensional trajectory of stator surface, including the influence of the input voltage on the phase and amplitude of the displacements in three directions, are investigated. The results show that the trajectory of particles on the stator surface is an ellipse in three-dimensional space due to the phase differences between the three components of displacement in the radial, circumferential and axial directions. The amplitude of radial displacement is about 39.5% of that in the circumferential displacement, which should not be neglected.
Ultrasonic testing of axial stress of high strength bolts for bridges
Authors: Feng Sheng , Tu Jun , Wei Shilin , Chi Yongbin , Zhang Xu , Song Xiaochun
Published: September 2020

The axial stress of high strength bolts for bridges affects the service life directly, it is necessary to measure it regularly. Based on the theory of acoustic elasticity and combination of longitudinal and shear waves, a new theoretical analysis method is proposed. The stressed and non-stressed areas of bolt are separated, and the derived formula only use the flight time and difference of acoustoelastic coefficients to get axial stress. Further, the preload experiments with high strength bolts of grade 8.8S and 10.9S is designed, the experimental results show that the proposed method is applicable to the axial stress of the bridge bolts with any specifications, material and different screwing depth used in this paper, the effect of elastic deformation on the flight time is eliminated, and the measuring error is within 5%.
Development of spoke-type IPM magnetic gear
Authors: Mizuana Yuma , Nakamura Kenji , Suzuki Yuma , Oishi Yuhei , Tachiya Yuichi , Kuritani Kingo
Published: September 2020

Magnetic gears can change output-torque and -speed without any mechanical contacts. Therefore, they have a low acoustic noise and vibration, and their maintainability and reliability are high. Especially, a flux-modulated type magnetic gear is expected to be put into practical use because its torque density is higher than that of other magnetic gears. For the practical use, further improvement of torque and losses is important, especially, reduction of eddy current loss in permanent magnets (PMs) due to asynchronous harmonic magnetic fluxes is necessary. This paper investigates an interior permanent magnet (IPM) structure to improve the efficiency by reducing the eddy current loss in PMs. In addition, this paper presents a method for increasing torque of the IPM magnetic gear by changing a position of magnetic-bridge.
Performance study on newly developed AC magnetic suspension system using magnetic resonance coupling
Authors: Rahman Arifur , Mizuno Takeshi , Ishino Yuji , Takasaki Masaya , Yamaguchi Daisuke
Published: September 2020

A newly developed AC magnetic suspension system is designed and fabricated to investigate the performances. A new concept of design is revealed for operating the apparatus differentially where the floator is kept at a constant position despite changing the parameters of the upper stator electromagnets. An extensive finite element analysis is conducted to estimate the basic characteristics of the system. A permanent magnet is incorporated in this system to reduce the required supply energy to the stator electromagnets. Magnetic suspension with a maximum gap of 2.0 mm without any control with the upper electromagnet in cumulative coupling mode and with a gap of 3.0 mm with indirect damping in the differentially operated mode is achieved. The indirect damping is achieved by applying PD control to the stator. The individual force, current and phase for variable frequency and gap between primary and secondary electromagnet are measured to examine the basic characteristics and performances.
Novel array ECT probe with three-phase excitation for steam generator tube inspection
Authors: Bai Yinghao , Zhang Na , Peng Lei , Li Xiaoguang , Kong Yuying , Tao Yu , Ye Chaofeng
Published: September 2020

Eddy current testing (ECT) is commonly used in steam generator tube inspection. Among multiple probes applied in this area, array probe shows the merit of the capability of obtaining a C-scan image in a simple linear scan. In this work, a novel array ECT probe with three-phase excitation is proposed. The probe consists of two rows of excitation coils and a row of pickup coils. The induced eddy current shifts electrically in the testing sample so that the necessity of multiplexer is eliminated, resulting in advantages of lower cost, less noise and faster inspection speed. Theoretical analysis indicates that the background signal of the array sensor would be small. A 3D finite element method (FEM) model is developed to study the operating principle and to predict the inspection performance of the probe. A prototype probe has been developed and tested, by which a steam generator tube sample with different kinds of defects was inspected. The experiment results validate the simulation model and further demonstrate the feasibility of the sensor.
Thermal conduction anisotropy of a magnetic functional fluids utilizing cluster formation of dispersed fine particles (in the case of micron-sized graphite particles)
Authors: Ido Yasushi , Iwamoto Yuhiro , Inden Takuya
Published: September 2020

The thermal conductivity of a magnetic fluid is expected to enhance by adding micron-sized particles with high thermal conductivity. The thermal conductivity of the magnetic fluid containing micron-sized graphite particles was investigated experimentally. The shapes of the graphite particles were sphere and flake-like. As the results of visualization experiments using the dark field microscope, the spherical graphite particles form chain-like clusters under applied magnetic field, while the fibrous structure is formed by the flake-like graphite particles, however, chain-like cluster formation cannot be clearly observed. The experiments using the transient hot-wire method showed that the thermal conductivity of magnetic fluid containing graphite particles is enhanced by applying magnetic field and by increasing the volume fraction of graphite particles.
Optimization design framework: Guiding the design of nonlinear structures with experimental data and machine learning
Authors: Zhou Jiaming , Dong Longlei , Yan Jian , Guan Wei
Published: September 2020

The optimization design of complex nonlinear structures mainly relies on expert experiences and trial and error. In this paper, we proposed an optimization design framework for nonlinear structures by combining experimental data and machine learning. The framework can search the entire design space and guide the next experiment by machine learning model until the optimization targets are met. To demonstrate the effectiveness and practicability of this framework, we have optimized the damping efficiency and principal resonance frequency (PRF) of an Electricity Distribution System (EDS) with eight rubber isolators. The results show that the design targets of the optimized structure are consistent with the experimental results after two iterations. This framework is able to guide and accelerate nonlinear structure design and has significant value for engineering applications.
Shear horizontal circumferential wave EMAT design for pipeline inspection based on FEM
Authors: Zhang Xu , Cheng Jiang , Qiu Gongzhe , Tu Jun , Song XiaoChun , Cai Chen
Published: September 2020

The electromagnetic acoustic transducer (EMAT) is widely used in In-Line Inspection of gas pipeline. However, the transduction efficiency of the EMAT transmitter is lower compared with the traditional piezoelectric transducer and needs improving. To enhance the amplitude of the received signal, an improved periodic-permanent-magnet EMAT is provided as well as its construction method to generate shear horizontal guided waves propagating in the circumferential direction. By designing a racetrack coil and magnetic array with the same radian of the annular pipeline, the EMAT is more suitable to generate the circumferential wave in the pipeline. The performance of the EMAT transmitter has been assessed with the validated finite element model.
Reliability analysis of helicopter emergency flotation system
Authors: Guo Xing , Sun Jian-Hong , Liu Ke , Zhang Tong , Li Ming-Qi , Ma Fang-Yun
Published: September 2020

The reliability of the emergency flotation system of helicopters is analysed by using fault tree analysis and the Monte Carlo method. We constructed a fault tree with the failure of system as the top event and obtained the minimal cut set, the ranking of the structural importance of the bottom events and the probability of the occurrence of the top event. Based on the system fault tree, a Monte Carlo simulation model of the emergency flotation system is established by using Matlab/Simulink. The results show that the Monte Carlo method is feasible and effective for the reliability analysis of the emergency flotation systems of helicopters. Furthermore, the comparison between the criticality importance and mode importance of each subsystem suggests that the control component is the weakest part of the emergency flotation systems, thereby providing a basis for system reliability design and fault diagnosis.
Heat transfer of temperature-sensitive magnetic fluids around single heating pipe
Authors: Iwamoto Yuhiro , Nakasumi Hayaki , Ido Yasushi , Niu Xiao-Dong
Published: September 2020

Temperature-sensitive magnetic fluid (TSMF) is a magnetic nanoparticle suspension with strong temperature-dependent magnetization even at room temperature. TSMF is a refrigerant that enables high heat transport capability and pumpless long-distance heat transport. To enhance the heat transport capacity of the magnetically-driven heat transport device using TSMF, it is effective to use a heating body with a very large heat exchange surface such as a heat sink or a porous medium. In the present study, the thermal flow of TSMF around a single heating pipe under a magnetic field was investigated. Visualization of the temperature field by infrared thermography showed that the application of the magnetic field dramatically developed the thermal boundary layer and improved heat transfer. It was clarified by numerical analysis that this dramatic variation in the thermal boundary layer was associated with several vortexes generated by magnetic force in the vicinity of the heating pipe.
Design and analysis of a PM-assisted brushless WRSM for improving torque characteristics
Authors: Sirewal Ghulam Jawad , Ayub Muhammad , Kwon Byung-il
Published: September 2020

This paper proposes a permanent magnet assisted brushless wound rotor synchronous machine (PMa–BL–WRSM) design. The proposed machine has the advantage of a high starting torque compared to existing BL–WRSM topologies. Additionally, the average torque increases and the torque ripple is reduced when the permanent magnet assisted machine structure is used. PMa–BL–WRSM operates on the principle of brushless excitation using zero-sequence, third-harmonic current generation in the stator windings. The third harmonic component is harnessed to induce a voltage in the harmonic winding which is mounted on the rotor. As there is no flux generated from filed winding in the starting, the starting torque of the machine is also zero. To overcome the problem, permanent magnets (PMs) are inserted in each field tooth to provide the initial source of flux on the rotor. Finite element analysis is performed with the PM–BL–WRSM, and the elicited results are compared with the basic machine structure. The proposed machine operation is verified using 2-D finite element analyses using the ANSYS Maxwell analysis tool.
A novel doubly salient electro-magnetic generator with symmetrical phase magnetic circuits: Basic topology, analysis, and experimental verification
Authors: Han Zhen , Shi Liwei , Yan Bing , Zhang Wenchao
Published: September 2020

The field winding of conventional multiphase doubly salient electro-magnetic generator is wound across multiple stator poles. There is a problem that the flux paths of the respective phases are not completely symmetrical. A novel E-core stator was proposed, the basic topology of the multi-phase E-core doubly salient electro-magnetic generator (E-core DSEG) with symmetrical phase magnetic circuits is derived by using the electrical formulas. This establishes a theoretical basis for the design of multiphase E-core DSEG. Based on the finite element simulation software, the static characteristics of multi-phase E-core DSEG were analyzed, including magnetic field distribution no-load electromotive force, flux linkage, self-inductance of field winding, cogging torque and so on. Finally, a prototype of three phases 18/20-pole generator was made and tested. The rationality of theoretical analysis and generator topology was verified by simulation and experiment.
Measurement system of swallowing motion by using a piezoelectric film sensor
Authors: Kurishima Yusuke , Hashimoto Hirokazu , Okuyama Takeshi , Tanaka Mami
Published: September 2020

In this paper, a measurement system of swallowing motion is developed. A piezoelectric film is used as sensitive material of the sensor to measure the body surface deformation due to swallowing. We focused on laryngeal prominence and digastric muscle which are active during swallowing and developed sensors to attach to skin above laryngeal prominence and digastric muscle. As a result of experiments, it was confirmed that output fluctuation occurred at the swallowing. Next, by comparing the frequency spectral density distribution of sensor outputs during swallowing and resting, it was found that the output waveform during swallowing is mainly composed of larger frequency components below 20 [Hz] than that during resting. From the results, it was suggested that the developed measurement system is available to detect the swallowing from skin deformation without obstructing the motion.
Modeling and simulation analysis of oil-free scroll compressor driven by magnetic force
Authors: Shi Ce , Sun Feng , Dou Rutong , Ren Huizhi , Li Qiang , Xu Fangchao , Zhang Xiaoyou
Published: September 2020

In order to solve the problems of wear, lubrication and complex structure of digital oil-free scroll compressor, an oil-free scroll compressor driven by magnetic force is proposed in this paper. The new scroll compressor is driven by electromagnetic force, without anti-rotation mechanism and motor, which reduces mechanical contact, so as to achieve the goal of low wear and oil-free. Back pressure device provides variable axial magnetic force to reduce the vibration of the compressor and ensure that the compressor works under the optimum force. The mathematical model of back pressure device and driving force is established and verified by finite element method. The results are in good agreement. The closed-loop step response of the new compressor is simulated. The gas force is decomposed and analyzed. The analysis, calculation and simulation results show that the back pressure device and the driving device meet the requirements of the compressor.
Propose of electromagnetic actuator for high efficiency EDM
Authors: Luan Boran , Sun Feng , Qi Shengfei , Xu Fangchao , Li Qiang , Zhang Xiaoyou , Yang Guang
Published: September 2020

In this paper, a kind of electromagnetic actuator is developed which can solve the problem of in time controlling inter-electrode gap in traditional EDM. An incoming current in the coil of an electromagnetic actuator generates Lorentz forces that cause the electrode to move axially. When the electromagnetic actuator is working, electrode is actuated positioned quickly, and electrode is produced a displacement of plus or minus 1 mm by control. The experiment shows that the response time of the electromagnetic actuator can meet the machining requirements. The discharge probability is increased and the machining efficiency is improved.
Electric characteristics of capacitors using a conductive transparent film for an application to wireless power transfer
Authors: Watanabe Tomoki , Kato Ryota , Murata Koki , Kiryu Shogo
Published: September 2020

Wireless power transfer technologies have been developing in various fields. One method of the wireless power transfer is one using electric field coupling. Capacitors are used in the method. If transparent conductive film as the electrodes are used, electric power can be transfer through a window glass. In this report, as an initial study for a wireless power feeding through a window glass, the electric characteristics of capacitors using a transparent conductive film were investigated. At first, the capacitances and the electric losses were measured. Next, a new capacitor structure was proposed in order to reduce the electric losses. The transparent conductive film was divided and connected in parallel. The total loss resistance was reduced from 22.4 Ω to 5.30 Ω by using the structure. The transmission efficiencies were measured of 53.7% for the load resistance was 9.74 Ω, 85.9% for 45.9 Ω, and 97.1% for 97.9 Ω.
Analysis of magnetic force and dynamic characteristic for non-contact permanent magnet linear drive device
Authors: Zhao Chuan , Sun Feng , Jin Junjie , Bo Mingwei , Xu Fangchao , Zhang Xiaoyou
Published: September 2020

This paper proposes a computation method using the equivalent magnetic circuit to analyze the driving force for the non-contact permanent magnet linear drive system. In this device, the magnetic driving force is related to the rotation angle of driving wheels. The relationship is verified by finite element analysis and measuring experiments. The result of finite element simulation is in good agreement with the model established by the equivalent magnetic circuit. Then experiments of displacement control are carried out to test the dynamic characteristic of this system. The controller of the system adopts the combination control of displacement and angle. The results indicate that the system has good performance in steady-state error and response speed, while the maximum overshoot needs to be reduced.
Investigation on spin relaxation of microfabricated vapor cells with buffer gas
Authors: Han Runqi , You Zheng , Shi Yue , Ruan Yong
Published: September 2020

MEMS vapor cells with buffer gas are the core components of chip scale atomic sensors due to the spin precession. We microfabricated rubidium vapor cells filled with neon based on MEMS technology and characterized the performance of MEMS vapor cells by measuring the longitudinal relaxation time. The dependence of spin relaxation time on buffer gas pressure and cell temperature was theoretically and experimentally investigated and the consistency was achieved. This provides a potential simpler approach to evaluate the performance of chip scale atomic sensors, such as atomic magnetometers, based on MEMS vapor cells.
Analysis of nonlinear vibration energy harvesters using a complex dynamic frequency method
Authors: Wang Zhixia , Wang Wei , Zhang Qichang , Gu Fengshou , David Ball Andrew
Published: September 2020

To understand the complicated dynamic behavior of a Nonlinear Piezoelectric Energy Harvester (NPEH), this paper develops an improved Complex Dynamic Frequency (CDF) method based on complex normal form. CDF introduces a dynamic frequency factor and establishes a set of algebraic equations in handling the effect of higher-order nonlinear terms in a wide frequency band to obtain periodic responses of NPEH. Numerical and experimental studies verify that the proposed CDF gives consistent and accurate predictions of the systems with both weak and strong nonlinearity. Furthermore, through an implicit relationship between magnet arrangement and output performance, one may effectively control the sweep frequency with softening and hardening characteristics. That is a major breakthrough toward the further nonlinear design for broad bandwidth harvesters. As the application, the experimental results reveal the high response profiles can be in a wide frequency range from 10.8 Hz to 24.5 Hz for the NPEH developed that allows an output power of 9 times higher than the conventional linear structure.
Minority Enrollment in Parkinson’s Disease Clinical Trials: Meta-Analysis and Systematic Review of Studies Evaluating Treatment of Neuropsychiatric Symptoms
Authors: Di Luca Daniel G. , Sambursky Jacob A. , Margolesky Jason , Cordeiro Joacir Graciolli , Diaz Anthony , Shpiner Danielle S. , Moore Henry P. , Singer Carlos , Luca Corneliu
Published: September 2020

Background: Randomized clinical trials (RCTs) in Parkinson’s disease (PD) have historically enrolled a low number of underrepresented minorities, lessening the generalizability of therapeutic developments. Although there are racial disparities in PD, little is known regarding neuropsychiatric symptoms and other nonmotor manifestations across all races/ethnicities. Objective: To assess minority participation in PD trials evaluating the treatment of neuropsychiatric symptoms and explore underlying reasons. Methods: We systematically searched PubMed and Embase for RCTs with a primary goal of treating neuropsychiatric symptoms in PD patients from 2000-2019. The pooled prevalence and 95% confidence interval (CI) of being white and enrolled in a clinical trial was calculated using the inverse variance method. I-square was calculated as a measure of heterogeneity and meta-regression was used to evaluate temporal trends. Results: We included 63 RCTs with a total of 7,973 patients. In pooled analysis, 11 (17.5%) RCTs reported race/ethnicity. Of studies reporting this data, 5 African American (0.2%), 16 Hispanics (0.64%), and 539 Asians (21.44%) were enrolled. The pooled prevalence of being white in clinical trials was 98% (CI 0.97–0.98, p < 0.001), with 1,908 patients (75.8%). NIH-funded studies were most likely to report racial data when compared to non-NIH trials (p = 0.032). Conclusion: This large pooled analysis found a small percentage of RCTs reporting race/ethnicity when evaluating treatment of neuropsychiatric symptoms in PD. There was a disproportionally high number of white patients when compared to African Americans and Hispanics. More studies are needed to investigate this discrepancy and improve rates of & minority enrollment in PD trials.
Fracture phenomena of float glass measured by the quasi-static method
Authors: Aratani Shin’ichi , Egawa Hiroyuki , Ohmi Toshihito , Yokobori A. Toshimitsu
Published: September 2020

Glass fracture and changes in bending load were investigated by the quasi-static loading method which is characterized by holding a fixed time at each displacement level and incrementally applying displacement. Holding time at each step was 60 s and the incremental displacement was 0.02 mm as the load condition. Ordinary soda-lime-silicate float glass of 50 × 10 × 4 mm was used as the specimen. The glass fracture occurred as the bending load decreased with time, which might be explained using the occurrence of time-dependent fracture and function as a viscoelastic property even at room temperature. Fracture properties of alumina ceramics have the possibility to be closer to float glass than silicon carbide which is called general ceramics.
The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from COVID-19: A living rapid evidence review with Bayesian meta-analyses (version 7)
Authors: Simons David , Shahab Lion , Brown Jamie , Perski Olga
Published: September 2020

Aims: To estimate the association of smoking status with rates of i) infection, ii) hospitalisation, iii) disease severity, and iv) mortality from SARS-CoV-2/COVID-19 disease.

Design: Living rapid review of observational and experimental studies with random-effects hierarchical Bayesian meta-analyses. Published articles and pre-prints were identified via MEDLINE and medRxiv.

Setting: Community or hospital. No restrictions on location.

Participants: Adults who received a SARS-CoV-2 test or a COVID-19 diagnosis.

Measurements: Outcomes were SARS-CoV-2 infection, hospitalisation, disease severity and mortality stratified by smoking status. Study quality was assessed (i.e. ‘good’, ‘fair’ and ‘poor’).

Findings: Version 7 (searches up to 25 August 2020) included 233 studies with 32 ‘good’ and ‘fair’ quality studies included in meta-analyses. Fifty-seven studies (24.5%) reported current, former and never smoking status. Recorded smoking prevalence among people with COVID-19 was generally lower than national prevalence. Current compared with never smokers were at reduced risk of SARS-CoV-2 infection (RR=0.74, 95% Credible Interval (CrI) = 0.58-0.93, τ = 0.41). Data for former smokers were inconclusive (RR=1.05, 95% CrI = 0.95-1.17, τ = 0.17) but favoured there being no important association (21% probability of RR ≥1.1). Former compared with never smokers were at somewhat increased risk of hospitalisation (RR=1.20, CrI = 1.03-1.44, τ = 0.17), greater disease severity (RR=1.52, CrI = 1.13-2.07, τ = 0.29), and mortality (RR=1.39, 95% CrI = 1.09-1.87, τ = 0.27). Data for current smokers were inconclusive (RR=1.06, CrI = 0.82-1.35, τ = 0.27; RR=1.25, CrI = 0.85-1.93, τ = 0.34; RR=1.22, 95% CrI = 0.78-1.94, τ = 0.49 respectively) but favoured there being no important associations with hospitalisation and mortality (35% and 70% probability of RR ≥1.1, respectively) and a small but important association with disease severity (79% probability of RR ≥1.1).

Conclusions: Due to incomplete recording of smoking status, there is uncertainty about the associations of smoking with COVID-19 outcomes. Current smokers were at reduced risk of SARS-CoV-2 infection. Former smokers were at increased risk of hospitalisation, disease severity and mortality from COVID-19, while data for current smokers inconclusively favoured no large associations with these outcomes.
PENERAPAN PEMBELAJARAN BAHASA INGGRIS BERBASIS KEARIFAN LOKAL DI MA MIFTAHUTTHOLIBIN KUNINGAN
Authors: Muhammad Iip , Gumiandari Septi , Huriyah Huriyah
Published: September 2020

Iip muhamad anwarul kholiq, Penerapan Pembelajaran Bahasa Inggris berbasis Kearifan Lokal di MA Miftahuttholibin Program Studi Manajemen Kuningan , Magister Fakultas Tarbiyah Dan Keguruan Pascasarjana IAIN Syech Nurjati 2020. Penelitian ini dilatarbelakangi observasi di MA Miftahuttholibin Kuningan. Menemukan kasus di MA Miftahuttholibin Kuningan adalah satu-satunya sekolah menengah kejuruan di Kota Kuningan yang mengusung sejarah budaya dan kesenian Kuningan sebagai program keahliannya. Sekolah Menengah SMK yang mengusung teknologi dan jurusan yang ramai peminat, sekolah ini berpegang teguh pada Norma dan nilai luhur budaya khusus budaya Kuningan.Tujuan penelitian adalah membangun pembelajaran bahasa Inggris berbasis Kearifan Lokal adalah menyediakan pelajar dan masyarakat untuk cara belajar Bahasa Inggris dengan baik, serta meningkatkan ketertarikan pelajar dan masyarakat tentang pembelajaran bahasa berbasis Kearifan Lokal. Metode penelitian ini adalah penelitian kualitatif deskriptif, dimana yang menjadi subjek penelitian ini adalah peserta didik kelas X, XI, XII, di MA Miftahuttholibin Kuningan, yang dilengkapi 120 Siswa.Penelitian Â ini Â dilaksanakan Â kurangÂ  lebih Â 3 Â bulan Â mulai Â dari Â bulan Â Juli sampai September 2018. Penelitian dimulai dari observasi, wawancara dengan kepala sekolah, guru, karyawan/staf, siswa dan orang tua anak. Pengumpulan data dalam Â penelitian Â iniÂ  menggunakan Â metode Â observasi, Â wawancaraÂ  dan dokumentasi. Adapun Teknik analisis data yang digunakan adalah reduksi data, display data dan verifikasi.Hasill Â penelitian Â Pertama, Â pembelajaran Â bahasa inggris berbasis Kearifan Lokal sangat penting diterapkan di MA MiftahuttholibinÂ  Kuningan, selain bahasa inggris yang sudah menjadi bahasa internasionalÂ  tetapi merupakan salah satu bahasa wajib di praktekan sehari-hari di sekolah smk ini sehingga memudahkan peserta didik menerima dan mengaplikasikan pembelajaran bahasa inggris berbasis Kearifan Lokal di sekolah. Kedua, cara implementasi pembelajaran bahasa inggris berbasis Kearifan Lokal dengan pendekatan tiga pola yaitu pola pembiasaan/pengulangan, Â polaÂ  contoh, Â dan Â pola Â implementasi Â dan Â evaluasi. Ketiga, Guru tidak mendukung hasil belajar Akan tetapi produksi proses belajar Lingkungan juga berkolaborasi mulai dari Lingkungan Keluarga, Sekolah dan masyarakat. penghambat dalam pembelajaran berbasis Kearifan Lokal dengan menggunakan bahasa inggris pada pelajaran bahasa inggris. kurang media konkret dan buku yang dijadikan sumber untuk belajar.Kata kunci: Pembelajaran Bahasa Inggris berbasis Kearifan Lokal
电气工程自动化技术在机械设备中的应用探究
Authors: 李 娟
Published: September 2020

随着机械制造行业的不断发展，电气工程自动化技术的水平也在日益提高，而将电气工程自动化技术融入到机械设备当中，又能极大地提高机械设备的综合性能，并使其生产效率得到有效提升，目前电气工程自动化技术已经在机械生产的各个领域中应用开来，本文就电气工程自动化技术在机械设备中的应用情况进行探究。
绿色建筑材料在土木工程施工中的有效应用分析
Authors: 万 海重
Published: September 2020

随着建筑行业的发展，建筑行业不断对绿色环保进行深入的优化，使工程朝着低碳环保、可持续发展的方向前进。在土木工程施工中使用绿色建筑材料是建筑行业转型的重要发展方向，其不仅能够满足人们对绿色环保生活环境的要求，而且能够推进建筑行业的前进。本文首先介绍了绿色建筑材料以及其在土木工程施工中应用的重要意义，并阐述了绿色建筑材料在土木工程中的具体应用，而且还提出了绿色建筑材料的发展建议，希望能够为建筑行业的绿色环保发展提供参考。
沧州县域特色产业外贸基地建设背景下跨境电商人才培养研究
Authors: 成 慧敏 , 常 聪敏 , 尹 玉
Published: September 2020

随着跨境电商的高速发展,越来越需要更多的专业人才来满足跨境电商发展的需要。通过对跨境电商的岗位设置以及职业素质的需求出发,深入探讨在沧州县域特色产业外贸基地建设背景下,如何培养新型的跨境电商人才,进而制定具体的培养目标和可实行的计划,同时加强师资队伍建设,将企业和学校紧密联系在一起,共同培养新型人才。基于此,本文深入研究分析了沧州县域特色产业外贸基地建设背景下跨境电商人才培养。
对加强水文水资源勘测合理开发利用水资源探究
Authors: 宋 婧 , 白 斌
Published: September 2020

水是人民群众生活中不可或缺的重要资源，同时水资源合理利用还可以为我国经济发展带来帮助，所以在近几年社会发展过程中有关部门就加大了对水利工程的关注度，同时也在水利工程建设中给与了一定帮助。提到水利工程建设就不得不说水文资源勘测，因为这一工作环节是水利工程建设的基础工作，并且有关部门在近几年发展中也在不断的提高水文水资源勘测质量，以保证在水利工程建设中能够将水资源合理应用，进而推动地区社会与经济发展。那么本文就针对如何利用水文水资源勘测来保证水资源合理利用进行论述。