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The micro crawling robot exhibits significant potential applications in various fields such as fault detection, disaster relief, and environmental monitoring. This article introduces a high‐performance millimeter scale crawling robot driven by a miniature electromagnetic linear actuator (MELA) with a body length of 5–6 mm and a mass of 80 mg. In this article, the working principle of the micro robot is analyzed and validated, and the influence of current, frequency, and angle α between the direction of actuator's force and the crawling surface on the crawling speed are analyzed through experiments. Results show that the optimal α ranges from 50° to 55°, and a specific current and frequency are identified to achieve maximum crawling speed for robot with particular α. When α is 50°, with a current of 300 mA and a frequency of 200 Hz, the robot reached the maximum speed of 20.2 Body Length s−1(BL s−1). The proposed robot can crawl at 12 BL s−1 with a load of 110 mg, and support a maximum load of 400 mg. Additionally, the robot demonstrated diverse capabilities such as climbing on a 10° slope with a load of 110 mg, jumping on a 1 mm obstacle, and crawling on surfaces of various materials. [ABSTRACT FROM AUTHOR]

In recent years, the post‐harvest commercialization of fresh jujube sorting technology is backward, the efficiency of manual grading is low, and the application of machine vision technology in fruit grading has been a research hotspot. To improve the grading accuracy and speed of the fresh jujube machine vision grading machine, this study designs a method of fresh jujube machine vision grading using an electromagnetic synchronous actuator. The grading machine consists of an automatic distribution and arrangement system, an image acquisition and processing system, and a synchronous actuator assembly, which uses a sensitive electromagnet to adsorb a silicon steel switching buckling plate to execute the action. The image processing process includes an image color component, Sobel operator filtering, Otsu method binarization, and ellipse fitting to extract the color and size eigenvalues. The experimental results show that the date images can be acquired quickly and processed accurately with a processing speed of 50 ms per frame. In addition, the proposed actuator can be sensitively triggered with a response time of 40 ms. The grader successfully classified jujube into five size classes and one color class. The grading accuracy and non‐destructive rate reached 93.7% and 100%, respectively. The grading efficiency is 20 jujubes per second, with a maximum production rate of 1400 kilograms per hour. This grading machine realizes the requirements of high accuracy, high speed, and non‐destructive grading of fresh jujube and provides an important technical and theoretical basis for the development of machine vision jujube rapid grading technology. Practical applications: In recent years, sorting technology in the post‐harvest commercialization of fruits has been outdated, and manual grading has been inefficient. The application of machine vision technology in fruit grading has been a research hotspot in recent years. This study designs a machine vision grading of fresh dates with an electromagnetic synchronous actuator. The grader was composed of a roller conveyor, synchronous actuator assembly, image main processor, and actuator controlling co‐processor. Experimental results indicated that jujube images could be acquired rapidly and processed accurately, with a processing speed of 50 ms per frame. In addition, the proposed actuator could be sensitively triggered with a response time of 40 ms. Finally, the grader successfully sorted jujubes into five size classes and one color class. The grading accuracy rate and non‐destructive rate reached 93.7% and 100%, respectively. The grading efficiency was 20 jujubes per second, and the maximum productivity was 1400 kg/h. [ABSTRACT FROM AUTHOR]

The rapid advancements in artificial intelligence, particularly in the domains of robotics, prosthetics, and virtual and augmented reality (VR/AR), have driven an escalating demand for intuitive and effective human-machine interactions. Consequently, haptic devices, being electronic displays for the sense of touch, have drawn increasing attention. More efforts are in demand to develop stretchable and lightweight haptic devices that can trigger multiple mechanical cutaneous receptors using a single device. This work presents a new 3-modal 5-DOF stretchable haptic interface that is enabled by electromagnetic actuators and high-fidelity multi-layer metal printing. The haptic device renders rich haptic sensations (i.e., normal force, vibration, angular force, skin dragging) in one device, allowing for the comprehensive delivery of tactile information through the excitation of multiple cutaneous receptors. Additionally, haptic devices are designed to be compact, lightweight, and skin-compatible. The skin-like softness and stretchability enable intimate skin contact, which is crucial for efficient haptic information delivery. This feature prevents the impediment to natural movements of the skin and ensures the functional integrity of the device during daily deformations of the skin. Finally, three proof-of-concept demonstrations illustrate the potential of the reported multimodal haptic devices for advanced haptic interactions across various domains. [ABSTRACT FROM AUTHOR]

Metasurface with programmable configurations has attracted tremendous attention due to their exotic abilities to manipulate electromagnetic waves. Herein, an electrically reconfigurable metasurface for frequency selective transmission is developed based on ionic polymer–metal composite (IPMC) kirigami. First, low‐voltage driven IPMC actuators with stable actuation performance are realized, and then a thermomechanical equivalent model and a numerical electromagnetic analysis model are proposed for evaluating the deformation of the IPMC actuators and predicting the electromagnetic tunable properties of the IPMC kirigami metasurfaces, respectively. Subsequently, large‐area IPMC kirigami metasurfaces are proposed and produced by using programmable nanosecond laser micro‐processing technique that endows the uniformity of the kirigami units. Finally, the electromagnetic functionalities of these IPMC kirigami metasurfaces are researched and validated by experiments and numerical simulations. Both theoretical and experimental results demonstrate that the electromagnetic transmission frequency of the fabricated IPMC kirigami metasurface with 10 × 10 units can be tuned from 19.3 to 20.8 GHz by the application of a low voltage of 3 V. Compared with the existing reconfigurable metasurfaces, the proposed IPMC kirigami metasurface demonstrates clear advantages in its compact structure, lower driving‐voltage, low‐acoustic noise, and wide working frequency range. [ABSTRACT FROM AUTHOR]

In order to solve the problems of complex structure and the difficulty of neutral adjustment of the existing 2D valve electro‐mechanical converter, a kind of claw pole magnetic levitation torque motor (CPMLTM) was proposed, which automatically suspended the rotor in an axially and circumferentially neutral position by using the cogging torque and axial recovery forces between the stator claw pole and the rotor permanent magnet (PM). Compared with the conventional moving iron torque motor, it has positive magnetic stiffness, 1.54 times higher PM utilisation and 33.6% lower mass. A qualitative mathematical model of output torque is derived based on equivalent magnetic circuit model. Then, the response surface method was used to build the second‐order response surface model, and NSGA‐2 was used to optimise the design of five key structural parameters, and the non‐inferior solution sets satisfying the maximisation of the cogging torque, output torque and axial recovery force were obtained. The experimental prototype was developed, and static experiments were carried out on the experimental rigs. The results show that the relationship between the input current and the output angular displacement of the CPMLTM is linearly proportional when the magnetomotive force generated by the coil winding is from −50 to 50 A. [ABSTRACT FROM AUTHOR]

As robots more frequently fraternize with humans in everyday life, aspects such as safety, flexibility of tasks, and appearance become increasingly important. Soft robotics is attractive for new human‐close applications, but soft actuators constitute a major challenge both in terms of actuation force and speed, and in terms of control and accuracy of the deformable soft actuator body. Herein, several of these challenges are addressed by developing versatile ultrasoft electromagnetic actuators that operate in absence of external magnetic fields, while simultaneously monitoring their states by internal strain sensors. The versatile actuators can compress to less than 50% of their initial length with strain‐independent contraction force and operate in both contraction and expansion modes up to 200 Hz frequency while conforming to curved surfaces. The soft multilayer conductive cellulose‐based foams are lightweight (3 mg cm−3) and provide internal strain‐sensing capability and structural support, thereby improving the monitoring and controllability of the actuators while maintaining an axial softness of 0.6 kPa. It is believed that the concept of soft versatile electromagnetic actuators with integrated lightweight strain‐sensing foams is promising for a wide range of applications within soft robotics. [ABSTRACT FROM AUTHOR]

To reduce structural responses under earthquake excitations effectively and improve their resilience, a smart structure with a semiactive tuned mass damper (STMD) on the top story and a semiactive adjustable stiffness device (SASD) on the first story which contributes to the structural adaptive stiffness property is developed in this study. The SASD consists of a diamond spring device composed of four linear springs and an electromagnetic actuator, which can change the angle of the diamond device and therefore retune the stiffness. Two typical STMDs developed previously are reviewed first, which are diamond device‐based STMD with variable stiffness and damping and pendulum‐type STMD with variable frequency and eddy current damping, respectively. Numerical results show that the proposed STMD has a better control performance than passive‐tuned mass damper and STMD with variable stiffness or damping acting independently. To enhance the seismic protection of the structure with an STMD on the top story further, based on the principle of base isolation, a diamond device‐based SASD is applied to the first story. The linear quadratic Gaussian‐based variable stiffness algorithm for SASD is proposed. A 10‐story building is presented as a case study. The variable stiffness range of SASD is discussed in detail, while it is found that a ±50% variable stiffness range achieves the best earthquake mitigation. Control effects of different numbers of SASD implemented along the height of the building are compared as well. Numerical results show that with the increase in the number of SASDs, the earthquake mitigation effect is better; however, the magnitude of the increase is decreasing. The smart structure with the combined SASD and STMD has an excellent seismic protection performance and is better than with SASD or STMD acting independently. Meanwhile, it is found that the proposed combination has a similar control effect to four SASDs installed from the first story to the fourth story, respectively, while it can reduce the number of additional electromechanical systems and the influence on the use function of the building. [ABSTRACT FROM AUTHOR]

Multilayer flexible electronics have broad applications in the fields of sensors, biomedicine, flexible displays, etc. The existing multilayer flexible electronic manufacturing methods are complicated and usually require multiprocess and multiequipment combinations for processing; especially, it is difficult to achieve integrated manufacturing. The increase in the overall thickness of multilayer flexible electronics also limits its flexibility, stretchability, and spatial density. Herein, a method for integrated multinozzle 3D printing of multilayer flexible electronics with thin structures is proposed and a new strategy for interlayer interconnection is presented. Printing high‐viscosity stretchable silver paste on the edge of the multilayer dielectric material and avoiding microholes and vertically printed conductive micropillar structures in traditional interlayer interconnection wires are discussed. The influences of process parameters on the fabrication of multilayer and thin flexible electronics are explored, and the minimum layer thickness for the fabrication of multilayer circuits is determined. A five‐layer flexible pressure sensor and two flexible electromagnetic actuators with different coils are fabricated, and the related performance tests of the two devices are carried out. The test results demonstrate that the proposed fabrication method of flexible electronics provides a high‐efficiency, low‐cost, and simple manufacture solution for the fabrication of multilayer and thin flexible electronics. [ABSTRACT FROM AUTHOR]

Boundary coordination is necessary for a shaking‐table substructure test (STST), which includes transferring forces and displacements between the tested and numerical substructures. Unlike other real‐time hybrid tests (RTHTs), the physical substructure is mounted on a shaking table and excited by the inertial force, which naturally requires a force control for boundary coordination. However, the natural velocity feedback in hydraulic actuators and high‐frequency noise in the force feedback signals makes it difficult to achieve force control. To solve these difficulties, in this study, a multi‐degree‐of‐freedom (MDOF) boundary‐coordinating device (BCD) is developed to simultaneously implement the boundary shear force and bending moment by the inertial force generated from shaking masses that are uniaxially driven by electromagnetic actuators. An STST framework was developed based on the BCD. The bottom two stories of a four‐story steel moment frame were selected as the physical substructure. A hydraulic shaking table was employed for ground excitation, and the BCD was used as the boundary coordinator for the numerical substructure, that is, the top two stories of the frame. To trace high‐frequency force signals, an enhanced three‐variable control (ETVC) method is proposed. Furthermore, an error‐response negative‐feedback compensation (ENC) method was developed to reduce the adverse effects of loading errors. Several rounds of STST tests demonstrated that the boundary commands were effectively traced by the BCD, so that the STST framework could consistently reproduce the seismic behavior of engineering structures. [ABSTRACT FROM AUTHOR]

Fast clearing of a short‐circuit fault is vital to increase the transmission capacity of power grid transmission lines and improve the transient stability of a power system. A fast vacuum circuit breaker (FVCB) is a good candidate to realize quick elimination of a short‐circuit fault. The original contribution of this paper is to present the design of a 72.5 kV single‐break FVCB and its verification of short‐circuit breaking performance. A specially designed 72.5 kV vacuum interrupter, with floating shields and reduced mass of moving components, was developed. An electromagnetic repulsion actuator was used to provide a high initial opening speed, V1, of 5 m/s over half of the full‐contact gap and a relatively low average opening speed, V2, of 1.59 m/s in the full contact gap of 30 mm. The high‐designed V1 and low‐designed V2 were achieved with the aid of a deliberately designed oil buffer. The opening and closing time of the designed 72.5 kV FVCB was 1.2 ± 0.04 ms and 18 ± 0.20 ms respectively. The terminal fault test duty of T100s(b), carried out on the 72.5 kV FVCB, demonstrated both the 40 kArms and 80 kArms short‐circuit current breaking performance. The short‐circuit current breaking arcing time windows of FVCB, including the minimum arcing time, the maximum arcing time, and the middle arcing time, was verified to fulfill the requirement of the international standard, IEC 62271‐100 2017, and the Chinese standard, GB/T 1984–2014, both for the 40 kArms and 80 kArms switching cases, respectively. Further development of the 72.5 kV single‐break FVCB would benefit the development of ultra‐ or extra‐high voltage FVCBs by reducing essential numbers of series‐connected breaking units. [ABSTRACT FROM AUTHOR]

The Riga surface is composed of an electromagnetic actuator that comprises a span‐wise associated array of discontinuous electrodes and an everlasting magnet mounted over a planer surface. The electro‐magneto‐hydrodynamic has an attractive role in thermal reactors, fluidics network flow, liquid chromatography, and micro coolers. Inspired by these applications, a laminar, two‐dimensional nanofluid flow with uniform heat sink‐source, thermophoretic depositions of the particles, and the Newtonian heating effect are investigated. The equations that describe the fluid motion are reduced into a system of ordinary differential equations with the help of spatial similarity variables. Numeric solutions of ordinary differential equations are executed through the Runge–Kutta–Felhberg 45 order technique via a shooting scheme. The role of various nondimensional factors on physically interesting quantities is elaborated graphically. The velocity profile rises for modified Hartmann number and decreases for porosity parameter. Thermal enhancement is high in the common wall temperature condition comparative to the case of the Newtonian heating conditions. The concentration profile is enhanced with Schmidt number, but the reverse trend is observed for the thermophoretic parameter. The rate of mass transfer is increased with Schmidt number. [ABSTRACT FROM AUTHOR]

Hydrogel actuators are ultrasoft and pliable but achieving high driving speeds with large deformation and fine local controllability is difficult because the driving force originates from the external air pressure or heat, and the base material is fragile. Herein, hydrogel actuators that allow high‐speed driving and large deformation with high‐frequency local controllability while maintaining softness are fabricated based on liquid metal gel fibers as electrodes by using microfluidic technology. The Lorentz force produced by an electric current and a magnet is used for actuation control. An ultrafast response of 260.5 mm s−1 with high‐frequency controllability (6 Hz) and a large deformation of 172% with hydrogel actuation are observed. As proof of concept, moving stages, micromixers, and grippers exhibiting high speeds with high mechanical deformability while maintaining the inherent characteristics of hydrogel phases are demonstrated. Different hydrogels can be used with the proposed actuator architecture and fabrication scheme, enabling different functionalities. [ABSTRACT FROM AUTHOR]

The importance of including an electromagnetic actuator as a moving boundary on the dissipative flows of weakly conducting fluids had led to many published facts. But, nothing is known on the generalized differential quadrature analysis of magnetohydrodynamics over a Riga plate with emphasis on the case of viscous dissipation and space‐dependent heat source. After deriving the simplified boundary layer equation that models the transport phenomenon, appropriate variables were used to non‐dimensionalize and parameterize the partial differential equations. Thereafter, the resulting set of ordinary differential equations was solved numerically by applying a powerful differential quadrature algorithm. Based on the outcome of the simulation, it can be concluded that the viscous frictional effect can be minimized at the Riga plate either by weakening the suction process or by heightening the magnetic parameter. Moreover, the Lorentz forces have a hastening effect on the fluid motion, in the case when those magnetic causes are directed in the same sense of the developed flow. [ABSTRACT FROM AUTHOR]

Small insect‐scale robots have demonstrated considerable promise in fields such as equipment fault diagnosis, environmental monitoring, scientific investigation, and disaster relief. However, realizing beneficial traits such as high‐speed motion, high load capacity, an internal driving source, and environmental suitability in one small robot is still challenging. Inspired by kangaroo hopping, a small robot is designed with a two‐mass soft structure and driven by electromagnetic force. With the synergistic effect of the hopping motion, the soft robot displays two unique properties: 1) the loaded speed is larger than the unloaded one (0–10 times its body weight) and 2) by changing the driving frequency, the moving direction of the robot, i.e., forward or backward, can be controlled. In addition, the robot displays multiple leading properties, including a high‐motion speed (≈21.5 body lengths s−1) and large load capacity (≈32.5 times its body weight), compared to other robots on the same scale. Furthermore, the robot displays exceptional adaptive capabilities under different circumstances: it traverses slopes, rough and soft surfaces, and even maneuvers underwater. The design strategy and dynamic model adopted in this research provide a reference for future designs and lay a solid foundation for the practical application of high‐performing small robots. [ABSTRACT FROM AUTHOR]

Our goal is to design, test and verify an electromagnetic actuator for brain magnetic resonance elastography (MRE). We proposed a grappler‐shaped design that can transmit stable vibrations into the brain. To validate its performance, simulations were carried out to ensure the electromagnetic field generated by the actuator did not interfere with the B0 field. The actuation vibration spectrum was analyzed to verify the actuation accuracy. Phantom and volunteer experiments were carried out to evaluate the performance of the actuator. Simulation of the magnetic field showed that the proposed actuator has a fringe field of less than 3 G in the imaging region. The phantom experiments showed that the proposed actuator did not interfere with the routine imaging sequences. The measured vibration spectra demonstrated that the frequency offset was about one third that of a pneumatic device and the transmission efficiency was three times higher. The shear moduli estimated from brain MRE were consistent with those from the literature. The actuation frequency of the proposed actuator has less frequency offset and off‐center frequency components compared with the pneumatic counterpart. The whole actuator weighted only 980 g. The actuator can carry out multifrequency MRE on the brain with high accuracy. It is easy to use, comfortable for the patient and portable. [ABSTRACT FROM AUTHOR]

A permanent magnet synchronous motor (PMSM) is introduced with 120° phase belts toroidal windings (PBTWs) (120°PBTWPMSM), in which its armature reaction field principle is elaborated. Then, the experiment concerning the 120°PBTWPMSM is conducted to verify the validity of the related analysis and the feasibility of the 120°PBTWPMSM. In addition, a method of shifting the magnetic poles (SMP) is adopted to suppress the cogging torque and the torque ripple. After this, the 120°PBTWPMSM after SMP is further optimised by the Taguchi method to obtain the structural parameters of the motor with optimal comprehensive performance. Finally, the performance of the original motor, the 120°PBTWPMSM after SMP and the optimal motor are compared, which verify the effectiveness of the optimization methods. [ABSTRACT FROM AUTHOR]

As stretchable devices become well established for applications in soft robotics and wearable devices, the compliant conductors that make these applications possible must also be reliable and survive for the entire device lifetime. Liquid metals such as Galinstan are a potential solution as non‐toxic, stretchable, and low‐resistance conductors. Rigorous investigations of liquid metal lifetimes, however, are limited. This work presents the median lifetime of liquid metal‐filled silicone tubes under current density on the order of 1 kAcm−2, which is necessary for applications such as electromagnetic actuators. In these conductors, the median lifetime increases by a factor of over 4700 as current decreases from 2 to 1 kAcm−2. By cooling the sample, median failure time increases from 112 s to 9.4 h, which suggests straightforward solutions to maximize liquid metal wire lifetime by increasing thermal conductivity or by duty cycling the applied current. [ABSTRACT FROM AUTHOR]

Minimally invasive medical procedures under magnetic resonance imaging (MRI) guidance have significant clinical promise. However, this potential has not been fully realized yet due to challenges regarding MRI compatibility and miniaturization of active and precise positioning systems inside MRI scanners, i.e., restrictions on ferromagnetic materials and long conductive cables and limited space around the patient for additional instrumentation. Lorentz force‐based electromagnetic actuators can overcome these challenges with the help of very high, axial, and uniform magnetic fields (3–7 Tesla) of the scanners. Here, a miniature, MRI‐compatible, and optically powered wireless Lorentz force actuator module consisting of a solar cell and a coil with a small volume of 2.5 × 2.5 × 3.0 mm3 is proposed. Many of such actuator modules can be used to create various wireless active structures for future interventional MRI applications, such as positioning needles, markers, or other medical tools on the skin of a patient. As proof‐of‐concept prototypes toward such applications, a single actuator module that bends a flexible beam, four modules that rotate around an axis, and six modules that roll as a sphere are demonstrated inside a 7 Tesla preclinical MRI scanner. [ABSTRACT FROM AUTHOR]

The usage of electromagnetic actuators in the continuous steel‐casting process is on a steady rise, due to its possibilities for a sophisticated, contactless flow control. The complexity of the casting process and the ever‐increasing quality demands require a well‐founded knowledge of the interaction between the electromagnetic actuators and the liquid steel flow. Numeric modeling provides a detailed view and is therefore crucial for understanding the interaction between the electromagnetic fields and the liquid steel flow. Only a deep insight into the coupling between the liquid steel flow and the electromagnetic forces makes it possible to improve/optimize the continuous casting process. The work presented here is part of an ongoing research to bridge the gap between the liquid steel flow and the grain structure of the end product. The article's focus lies on the liquid steel flow modified by a traveling magnetic field—relying mainly on numerical simulations. Different modeling approaches are used to simulate linear electromagnetic stirring in the secondary cooling zone of a slab caster. An appropriate model is chosen to investigate the influence of various stirring parameters, stirring modes, and stirring positions. From the results, conclusions for the real casting process can be drawn. [ABSTRACT FROM AUTHOR]

Wireless capsule endoscope (WCE) is a new diagnostic device that can be utilised for evaluating the whole digestive tract if effectively actuated. In this research, a new one degree of freedom (1DOF) actuation system based on a magnetic levitation concept is proposed for the capsule endoscope navigation system. The proposed system is used to move a permanent magnet inserted in WCE body by an arrangement of the current controlled electromagnetic actuator placed on a 3DOF movable frame. The aim of this study is to design a proportional–integral–derivative (PID) controller to suspend the capsule and keep it at a demand test region. DC and AC magnetic field‐based positioning systems using the Hall effect sensor and the coil sensor, respectively are used to provide the controller by capsule position feedback. Improvement of the position feedback accuracy based on AC magnetic field using discrete Fourier transform is presented. Realistic simulation design of the system is implemented using Matlab/Simulink environment to validate the PID controller. The navigation scheme is implemented practically utilszing digital signal processor to verify the effectiveness of the controller. Finally, simulation and experimental results of the capsule navigation system are presented to show the performance of the proposed controller. [ABSTRACT FROM AUTHOR]

Congestive heart failure is a pathology of global incidence that affects millions of people worldwide. When the heart weakens and fails to pump blood at physiological rates commensurate with the requirements of tissues, two main alternatives are cardiac transplant and ventricular assist devices (VADs). This article presents the design strategy for development of a customized VAD electromagnetic actuator. Electromagnetic actuator is a brushless direct current motor customized to drive the pump impeller by permanent magnets located in rotor–stator coupling. In this case, ceramic pivot bearings support the VAD impeller. Electronic circuitry controls rotation switching current in stator coils. The proposed methodology consisted of analytical numerical design, tridimensional computational modeling, numerical simulations using Maxwell software, actuator prototyping, and validation in the dynamometer. The axial flow actuator was chosen by its size and high power density compared to the radial flow type. First step consisted of estimating the required torque to drive the pump. Torque was estimated at 2100 rpm and mean current of 0.5 A. Numerical analysis using finite element method mapped vectors and fields to build stator coils and actuator assemblage. After tests in the dynamometer, experimental results were compared with numerical simulation and validated the proposed model. In conclusion, the proposed methodology for designing of VAD electromechanical actuator was considered satisfactory in terms of data consistency, feasibility, and reliability. [ABSTRACT FROM AUTHOR]

This article presents a design of a high thrust density moving magnet linear actuator for linear refrigerator compressor. The shape of permanent magnet (PM) shows great effect on cost, fabrication and magnetic flux density generation in the actuator. Axially magnetised disk shaped PMs are low cost and convenient for fabrication. Moreover, axially magnetised PMs generate high flux density in a specific direction compared to radial magnets. This paper investigates the design of axially magnetised moving magnet linear oscillating actuator (LOA) which operates on single phase alternating supply. Additionally, an alternative path is proposed for the return of magnetic flux from mover to the stator. Using finite element method (FEM) tools, all the parameters of LOA are optimised. Moreover, with the help of a specially designed experimental setup, FEM simulation results are validated. This actuator demonstrates great advancement in thrust force density, motor constant and output power compared to the size of proposed LOA. [ABSTRACT FROM AUTHOR]

The present study aims to investigate Marangoni‐forced convective nanofluid flow over an electromagnetic actuator (Riga plate). A first‐order homogeneous chemical reaction is considered. The thermocapillary and solutocapillary Marangoni effect developed by the surface tension is considered as a driving force for the nanofluid. In addition, Grinberg‐term is accounted to involve the impact of Lorentz force impinged by the actuator in the model. A set of nonlinear ordinary differential equations is obtained via suitable transformations for a nonsimilar analysis. Series solutions are achieved through homotopy to discuss the behavior of the velocity field, thermal distribution, and concentration of the nanoparticles graphically. The variation in Nusselt and Sherwood numbers is discussed. The outcomes declared that the flow parallel to the surface of the plate is assisted by the Lorentz forces generated by electromagnetic bars of the actuator resulting in an enhancement in the fluid motion. Furthermore, the stronger Marangoni effect resulted in the declining trend of the temperature profile. The concentration of nanoparticles near the surface reduced intensive chemical reaction inside the nanofluid. [ABSTRACT FROM AUTHOR]

This article addresses transient electromagnetohydrodynamic radiative squeezing flow due to convectively heated electromagnetic actuator. The transport analysis of heat and mass is explored considering the heat generation/absorption and destructive species homogeneous reaction. Suitable transformations are applied on the mathematical model developed to convert governing partial differential equations to ordinary differential equations (ODEs). Spectral local linearization method (SLLM) is employed on the resultant nonlinear coupled ODEs to compute the numerical results. Influence of sundry physical quantities on heat mass transfer of squeezing flow characteristics are determined using graphs and tabular results. SLLM results exhibit that momentum and temperature improved with rise in squeezing and heat source parameters correspondingly. Momentum enhances at lower plate and detracts with rise in modified Hartmann number. For improved heat source parameter, the rate of heat transfer diminishes and is more significant for higher Prandtl number values. This investigation has relevance in disk style magnetic clutches, rolling elements, food processing, bearings, squeezing film pressure sensors, and flow rheostats. [ABSTRACT FROM AUTHOR]

The need for faster power switches leads to the following question: Which technical actuation principle has the highest acceleration potential? This study describes the investigation of electrodynamic moving coil (voice coil) actuators. This principle promises no delay for the excitation field because of permanent magnets and a very small electrical time constant of the moving coil. The aim is to find out the limits of the switching time under practicable conditions. In the study, technical limitations of the actuation principle concerning the dynamic behaviour are shown by an analytical approach. It contains the major parameters like stroke or material of the iron poles, the coil, and the permanent magnets. Furthermore, the study discusses thermal aspects and approaches for the mechanical force multiplying by cascaded arrangements. A magnetically optimised elementary unit can be combined parallel or in series. The mechanical load inertial can be divided into a sufficient number of cascaded actuation units. Consequently, only the inherent moving mass determines the acceleration capability. This optimisation was done analytically with the Lorentz force formula and with finite element method simulations. This article describes both approaches, their results, and the experimental verification. The experimental actuator reaches a switching time of 2.7 ms. [ABSTRACT FROM AUTHOR]

The fast mechanical switch is one of the key devices for high-voltage direct-current circuit breakers (DCCB), and the mechanical contacts separation time determines the operating time of hybrid mechanical circuit breakers. With the increasing of the voltage and power levels of DC system, numerous technical challenges begin to emerge. For high-voltage system, the new research and the series arrangements of very fast mechanical switches include designing new drive unit to satisfy larger load mass and longer travel stroke. Aimed to reducing the peak value of electric force, a novel drive unit by using modular double capacitors has been proposed here. Based on the equivalent circuit method (ECM), the mathematical model of Thomson coil (TC) actuator which is the drive unit in fast mechanical switch is established. First, the time sequence of capacitance discharge is studied. Then, the electromagnetic force can be divided into five types in different time sequences, and the characteristics of the electromagnetic force are analysed. Finally, it is concluded that using a combination electromagnetic force with three approximate peaks can reduce the impact of the metal plate, which improve the reliability of the fast switch. [ABSTRACT FROM AUTHOR]

This paper uses FEA simulations to investigate the behaviour of a high-speed, high-power Thomson coil (TC) actuator suitable for HVDC protection applications, when excited by a double discharge. The influence of the resulting pulse train on the amplitude of observed armature vibration is investigated. The significance of the pulse train on the device electrical to mechanical energy conversion efficiency is assessed and compared with the efficiency obtained using the conventional single discharge approach. [ABSTRACT FROM AUTHOR]

The iron loss of inner yoke accounts for the majority of iron loss of an electromagnetic linear actuator (ELA). Therefore, the reduction of iron loss of inner yoke is of great importance to the reduction of iron loss of the whole ELA. This study investigates the formation mechanism and distribution law of ELA iron loss and proposes a reduction scheme by arranging groove structures in the inner yoke. The direction of groove arranged in inner yoke was determined based on the formation mechanism of inner yoke iron loss. Through simulation and calculation based on finite‐element model of electromagnetic field, the authors investigated the effects of the number of grooves as well as groove width on the iron loss and performance of ELA. The optimal grooving scheme of ELA was determined by comprehensive analysis and analytic hierarchy process. Finally, block and static force tests were carried out based on ELA prototype. It was found that the simulation results were consistent with test results, indicating the accuracy of the simulation model. [ABSTRACT FROM AUTHOR]

Here, a DC vacuum arc interruption test based on the hybrid high-speed actuator and the method of commutation is carried out in the synthetic loop system. The safe stroke is one of the basic breaking parameters. The minimum safe stroke directly determines the commutation time and breaking property of the mechanical DC vacuum circuit breaker. The main circuit breaker is a high-speed vacuum switch driven by electromagnetic repulsion actuator. In order to simplify its control system, the commutation switch also adopts high-speed vacuum switch. The main current source for verification test of this DC breaker system is provided by a LC oscillator circuit with lower frequency. Simulations with some experiments were completed on breaking process of this system by PSCAD. The breaking current is 4 kA by the DC breaker system proposed here, the opening speed is about 2.417 m/s in this experimental system; From the results, the simulation and experimental waveforms are compared and analysed, and some effects on safe stroke of the DC vacuum circuit breaker is studied. The shortest arcing time is about 0.89 ms and the minimum safe stroke is about 2.15 mm under the lower voltages. [ABSTRACT FROM AUTHOR]

In the 500 kV hybrid high-voltage direct current (HVDC) circuit breaker, there are five 110 kV fast mechanical switches (FMSs) in the nominal current path. When the detection system detects the failure of the hybrid circuit breaker, in order to protect the disconnectors or semiconductors, the FMSs are required to close quickly. The closing drive technology can be divided into two categories, based on the closing speed of the Thomson-coil actuator. One is based on the conventional closing drive, the open−close operating time of which is 20.0 ms. The other type is based on the fast closing drive, which is used under fault conditions and the total time is ∼7.5 ms. A 110 kV/3 kA prototype FMS employing an interrupter with a 30 mm maximum open gap and 4 kg total moving mass has been modelled based on the equivalent circuit method. Through the simulation, the effect of discharging time sequence on open−close operation has been studied, and the general timing control design principle has been provided. [ABSTRACT FROM AUTHOR]

Electromagnetic design of a moving magnet frictionless linear actuator with self‐holding functionality for mechanical gear shifting in a transmission application is presented. The actuator consists of a tubular magnetic circuit with stationary armature and axially moving rotating permanent magnet assembly with radial magnetisation in the air gap. The armature contains a two‐piece magnetic core with a space for a winding. The effects of armature slot opening and magnetic circuit materials on the self‐holding force and the acting force are studied in the whole moving range. The designed moving magnet linear actuator improves the performance of the vehicle by enabling shift times below 50 ms with no energy consumption between the shifts. [ABSTRACT FROM AUTHOR]

This study considers the design of surface‐mounted permanent magnet electrical machines for high‐speed applications and proposes a methodology to determine the maximum achievable power density. Power density is usually improved by increasing rotational speed. At high speed, a mechanical retaining system for the rotor magnets must be considered. As the speed increases, the thickness of the retaining sleeve becomes larger, reducing torque capability. There will be an optimal speed at which the output power will be maximised. Both structural and electromagnetic design must be considered simultaneously to properly address this design problem. To simplify the design procedure, static finite‐element simulations are used for the electromagnetic analysis and analytical formulae are employed for retaining sleeve sizing. The procedure is aided by multi‐objective optimisation algorithms. A case study based on the specification of an aeronautical actuator is presented. The performances that can be obtained using different iron cores, high‐grade silicon steel, and cobalt iron steel are compared. Finally, results obtained from transient finite‐element electromagnetic and structural analysis are presented to validate the feasibility of the proposed procedure. [ABSTRACT FROM AUTHOR]

Abstract: Response time is a central characteristic of sensors measuring solute concentrations. Knowing the response time of the sensor under realistic conditions is critically important when measuring rapid changes, e.g., oxygen concentration fluctuations for aquatic eddy covariance flux calculations. Response times therefore should be determined under conditions that are similar to those the sensor is exposed to when deployed for the actual measurements. This study introduces a new method for quantifying the response time of mini‐ or microsensors measuring solute concentrations in liquids and gases. The method is based on the rapid switching of the supply of two fluids with different oxygen concentration to the sensor without removing the sensor from the fluid flow. The device uses a jet nozzle moved by electromagnetic actuators, and the switching of the calibration fluids is monitored by a reference sensor with a response time < 0.001 s. The functionality of the device is demonstrated for a fast oxygen optode system that consisted of a fiber minioptode connected to an oxygen meter that was read by a data logger. With the setup described here, the method permits reproducible response time measurements with a resolution of 0.01 s ± 0.001 s (SD, n = 60). With this technique, the response time characterization of aquatic sensors can be standardized. [ABSTRACT FROM AUTHOR]

Abstract: Electromagnetic actuators (EMAs) serve the majority of motion control needs in fields ranging from industrial robotics to automotive systems and biomedical devices, due to their unmatched combination of speed, precision, force, and scalability. This paper describes the design and fabrication of miniature soft EMAs that operate based on the Lorentz force principle. The actuators are fabricated from silicone polymer, liquid metal (LM) alloy (eutectic gallium indium, EGaIn), and magnetic (NdFeB) powder. They are small, intrinsically deformable, and can be fabricated using simple techniques. The central elements of the actuators are fine, 3D helical coil conductors, which are used as electromagnetic inductors. The coils are formed from stretchable filaments that are filled with a LM alloy. To achieve high power densities, the filaments themselves may be fabricated from colloids of EGaIn microdroplets in a silicone polymer matrix, allowing them to dissipate heat and accommodate high currents, and thus high forces. Millimeter‐scale cylindrical actuators are demonstrated for linear high frequency motion and articulated devices for bending motion. These actuators are applied in a vibrotactile feedback display and in a miniature soft robotic gripper. [ABSTRACT FROM AUTHOR]

SUMMARY We have designed and developed a tri-stable rotary solenoid actuator, which has a simple structure and simple operation. The plunger has two stabilities at the extreme positions along an angular stroke and the third stability at the center of it. The third has been successively achieved by using the electromagnetic restoring torque, which is designed to be larger than the inertia torque. The dynamic characteristics were determined by utilizing an optimal design program that is specially constructed based on the response surface method in order to design the coil winding and the power supply for the coil excitation. A prototype solenoid was constructed and used to verify the tri-stable motions and accuracy of the previously constructed design program. [ABSTRACT FROM AUTHOR]

SUMMARY A closed-loop control system is commonly used in electromagnetic actuators to ensure operating performance. However, this system frequently leads to high costs. We developed a swing electromagnetic actuator with an integrated eddy current brake to reduce the operating time and improve the stopping accuracy. The developed actuator is a three-position cylindrical actuator moving within a ±120º angle without closed-loop control. The rotor is composed of a bulk and thin metal laminations and the stator has three sets of pairs of coils. The rotor is stopped at an intermediate position by magnetic force generated by the coils. This paper describes the electromagnetic design and its evaluation by using an FEM simulation to predict its operating characteristics and measure its performance on a test bench. The superiority of our actuator design is verified by comparing these measurements. The operating time is reduced to one-sixth of that of a laminated rotor and the over travel is compressed to zero. In addition, this actuator has the advantage that it is electrically robust against variations in the power supply. [ABSTRACT FROM AUTHOR]

SUMMARY A new mechanical CBM (condition-based maintenance) system for an electromagnetically actuated vacuum circuit breaker (VCB) has been developed. This CBM function has a new monitoring method using analysis of the coil current profile of the actuator operation. The VCB has three sets of vacuum interrupters, insulating rods, contact pressure springs, and electromagnetic actuators. The electromagnetic actuators control each phase independently. We have clarified the variation in the actuator's current profile by the developed analytical method when the valve of friction, contact erosion, and driving capacitance change. We have established a diagnostic method for the mechanical condition using this current profile analysis. With this method, a new remote monitoring system of the mechanical condition using current monitors on the actuator's controller has been developed and mounted on VCB for cubicle-type gas insulated switchgears rating from 7.2 kV to 84 kV. The maintenance for mechanical parts of VCB changes to the CBM system from the conventional TBM (time-based maintenance) system using this monitoring system. The developed mechanical CBM system significantly reduces the life cycle cost including the labor cost of maintenance. [ABSTRACT FROM AUTHOR]

ABSTRACT Electromagnetic analysis for transmission line structures plays an important role in the design of high-speed digital integrated circuits. Because different transmission line parameters have different influence on the integrity of the integrated circuit signal. In this article, method of moment combined with the Rao-Wilton-Glisson basis function and the dual basis function is established to solve the integral equations. Transforming the integral equations into matrix equations and achieve the analysis of the input impedance of transmission line structures. Numerical results have been demonstrated with two examples. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:219-223, 2017 [ABSTRACT FROM AUTHOR]

The diode is used as the detection unit to receive the millimetre-wave signal directly. A circuit is made with an operational amplifier OP27 to amplify the signal. The magnification of the OP27 circuit is stable at 100 <100 kHz. The performances of the detection terminal and the low-pass filter amplifying circuit are compared in different distance between the source and the diode with a polarisation angle of 70°. The result shows good sensitivity of the detection terminal in active millimetre-wave imaging. A one-dimensional imaging test on the detection terminal is performed. [ABSTRACT FROM AUTHOR]

Recently, remote‐controllable actuators for circuit breaker (CB) have attracted attention for the smart grid electric power system. In this study, diverse kinds of remote‐controllable electromagnetic actuator for CB are precisely investigated to give a guideline for the selection of the effective actuator according to numerous voltage level of CB. In case of a low‐voltage level of CB, the separated permanent‐magnet actuator (SPMA) is verified in this research as the most suitable actuator through the comparison with diverse electromagnetic actuators. The SPMA is designed for the 225AF moulded case CB by using the proposed optimisation method, which the authors termed as a multi‐step optimisation strategy. [ABSTRACT FROM AUTHOR]

The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. After an integrated luminosity of a few [ABSTRACT FROM AUTHOR]

In this overview presentation I report on selected Standard Model (SM) physics highlights obtained by the ATLAS and CMS experiments in the first three years of data taking (Run I) at the new Large Hadron Collider (LHC) at CERN. By far the most important and exciting result of LHC Run I has been the observation of a new boson with a mass of 125 GeV, consistent with the properties of the SM Higgs boson. The discovery of the Higgs boson has brought the last missing piece of the Standard Model but the talk has given also an overview of the main results on di-boson production, heavy flavour physics (b-quark rare decays and CP violation; top-quark mass and properties) and QCD. Finally a brief discussion on LHC future program. LHC is just now restarting operation at higher energy. New data will certainly give more detailed informations on the Higgs boson and by the end of this decade LHC experiments will have collected ten times more proton-proton (pp) collisions. The Standard Model processes have been holding up to scrutiny over several orders of magnitude in production cross section but we are just at the beginning of the TeV scale exploration. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The Large Hadron Collider (LHC) at CERN has allowed the ATLAS and CMS experiments to collect a large amount of proton-proton collision data at 7 TeV and 8 TeV centre-of-mass energies. This dataset was used to discover a Higgs boson with Standard Model-like properties at a mass of about 125 GeV. In parallel, an impressive number of searches for deviations from the Standard Model expectations have been carried out in various physics areas (BSM Higgs, Supersymmetry, and Exotics). Representative searches in all of these domains will be presented and their impact on theoretical models beyond the SM assessed. To date, there is no evidence in the LHC data of a signal for New Physics beyond the SM. However, a few legacy 2-3δ deviations remain from both experiments. After an 18-month shutdown, the LHC is about to deliver collision data at an increased centre-of-mass energy of 13 TeV. The large increase in collision energy will provide much improved sensitivity for various searches, in particular for high mass particles. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The forward acceptance of the LHCb detector allows it to probe proton-ion collisions in a unique kinematic range, complementary to the other LHC experiments. The production of J/Ψ and Υ-mesons decaying into two muons is studied at the LHCb experiment in proton-lead collisions at a proton-nucleon centre-of-mass energy √ sNN = 5 TeV. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb-1. The nuclear modification factor and the forward-backward production ratio are determined for J/Ψ and Υ(1S) mesons. Clear suppression of prompt J/Ψ production is observed with respect to the production in proton-proton collisions at large rapidity, while the suppression of J/Ψ from b-hadron decays is less pronounced. The nuclear modification factor for Υ(1S) mesons in the forward region is found to be similar to those for J/Ψ from b-hadron decays. Furthermore, a first observation of Z bosons at large rapidities in proton-lead collisions is reported. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The Pierre Auger Observatory addresses the most fundamental questions about the nature and origin of the highest-energy cosmic rays. The results obtained by the Auger Observatory have already led to a number of major breakthroughs in the field contributing to the advance of our understanding of these extremely energetic particles. The spectrum and the arrival direction distribution are key observables to search for sources or source regions of ultra-high energy cosmic rays, and to understand the transition from Galactic to extragalactic cosmic rays. We present the latest results on the energy spectrum, and on the studies of anisotropies performed on the ten-year dataset of arrival directions of cosmic rays at large and small angular scales. We also address the plans and motivations for the future upgrade of the Pierre Auger Observatory. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The Pierre Auger Observatory is the largest ultra-high energy cosmic ray experiment built so far. It is a hybrid detector, since it measures both the fluorescence light emitted while the air showers develop in the atmosphere and the particles reaching the ground. We present the results related to the mass composition of ultra-high energy cosmic rays as obtained from both types of measurements. The depth at which the maximum of the electromagnetic development takes place and its fluctuations are the most sensitive parameters to infer the nature of the cosmic rays. In addition, we present the latest muon measurements that can be used to test and constrain models of hadronic interactions at energies larger than those reached at LHC. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

BACKGROUND Microbioreactors have emerged as novel tools for early bioprocess development. Mixing lies at the heart of bioreactor operation (at all scales). The successful implementation of micro-stirring methods is thus central to the further advancement of microbioreactor technology. The aim of this study was to develop a micro-stirring method that aids robust microbioreactor operation and facilitates cost-effective parallelization. RESULTS A microbioreactor was developed with a novel micro-stirring method involving the movement of a magnetic bead by sequenced activation of a ring of electromagnets. The micro-stirring method offers flexibility in chamber designs, and mixing is demonstrated in cylindrical, diamond and triangular shaped reactor chambers. Mixing was analyzed for different electromagnet on/off sequences; mixing times of 4.5 s, 2.9 s, and 2.5 s were achieved for cylindrical, diamond and triangular shaped chambers, respectively. Ease of micro-bubble free priming, a typical challenge of cylindrical shaped microbioreactor chambers, was obtained with a diamond-shaped chamber. Consistent mixing behavior was observed between the constituent reactors in a duplex system. CONCLUSION A novel stirring method using electromagnetic actuation offering rapid mixing and easy integration with microbioreactors was characterized. The design flexibility gained enables fabrication of chambers suitable for microfluidic operation, and a duplex demonstrator highlights potential for cost-effective parallelization. Combined with a previously published cassette-like fabrication of microbioreactors, these advances will facilitate the development of robust and parallelized microbioreactors. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Two identical unprinted dielectric slabs are placed above a dual-polarised (DP) stacked-patch feed antenna to transform its less-directive radiation into almost equal and high-gain DP beams in two frequency bands. The dual-band operation is achieved by engineering the reflection characteristics of a classical all-dielectric superstructure such that cavity resonance condition is satisfied in two frequency bands. A prototype of this dual-polarised electromagnetic band gap resonator antenna with a frequency ratio of 1.245 has been fabricated and measured peak gains of 17 and 16.6 dBi at 10.6 and 13.15 GHz, respectively, and cross-polarisation levels of less than -18 dB, have been achieved. The proposed antenna has a simple configuration and is easy to manufacture, making it a good candidate for DP point-topoint wireless links. [ABSTRACT FROM AUTHOR]

Linear switched reluctance actuator (LSRA) is of great potential using in kind of high‐force linear applications such as automotive suspension system. In this study, an electrical controlled active suspension system is built. Bi‐directional power amplifier is used to supply power to and absorb generated energy from linear actuator based on the movement requirement. The linear motions are accomplished by retracting and extending the LSRA. With regard to the established electromagnetic suspension system, a real‐time control algorithm is developed. Sliding model technique with adaptive mechanism is studied to compensate the system non‐linearities and external road profile. Experiments are conducted at the laboratory to present the high performance of proposed active suspension system. [ABSTRACT FROM AUTHOR]