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We present a modified complex-valued Shimizu–Morioka system with a uniformly hyperbolic attractor. We show that the numerically observed attractor in the Poincaré cross section expands three times in the angular direction and strongly contracts in the transversal directions, similar in structure to the Smale–Williams solenoid. This is the first example of a modification of a system with a genuine Lorenz attractor, but manifesting a uniformly hyperbolic attractor instead. We perform numerical tests to show the transversality of tangent subspaces, a pivotal property of uniformly hyperbolic attractors, for both the flow system and its Poincaré map. We also observe that no genuine Lorenz-like attractors appear in the modified system. [ABSTRACT FROM AUTHOR]

In this paper, a comparative investigation of a C-band long-pulse high-efficiency klystron-like relativistic cavity oscillator is carried out by using numerical simulation and practical experiments. It is indicated that owing to the improper configuration of the solenoid, some returning electrons originating from the cathode supporting rod would hit the entrance of the diode and shunt the input electric power. As a result, the startup process of the device is delayed and the saturated output power is decreased as well. In the initial experiment, the output power and the pulse duration are only about 3.2 GW and 78 ns, respectively. To eliminate the influence of the returning electrons, by increasing the turn number of the winding at both ends of the solenoid, the magnetic field at the diode region is enhanced so that the returning electrons could be guided to the shielding bowl in front of the insulator. As the shielding bowl is under the same potential as the cathode, the returning electrons would not shunt the input power. In contrast, after solenoid compensation, the output power of the device is increased to 4.4 GW at a diode voltage of 700 kV and a current of 14 kA, whereas the pulse duration is extended to 96 ns. Also, the corresponding conversion efficiency achieves about 45%. [ABSTRACT FROM AUTHOR]

Copyright of Light Industry Machinery is the property of Light Industry Machinery Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study offers a mechanism to control low-speed orientation using semi-active control. The semi-active system consists of a variable mass system and a torsional spring. The torque generated by a variable mass system controls the platform’s orientation. An evaluation of the control system’s effectiveness is tested on a solar panel. The variable mass was represented by moving the water from one reservoir to another located at the left and right sides of the panel using an electrical pump. A solenoid valve controls the flow. The test results indicate that the energy consumption of electrical pump as actuators is reduced. Based on several references, the actuator energy consumption for controlling the orientation of solar panels was generally 2% - 3%, while in this study 0.79%. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Practicum tools are learning media that can increase students' interest and motivation to learn. The practicum tool itself is very effective and efficient in supporting physics learning. The magnetic field is related to electricity and magnetism because the magnetic field is generated by an electric current, there is a transfer of charge because the magnet creates a magnetic field around the magnetic charge. Hall effect sensors are used to measure magnetic fields. The purpose of this research is to assist students in understanding magnetism material and also to fulfill the availability of practicum tools in schools, especially SMA/MA. This research uses a type of quantitative descriptive research. The measurement results in the experiment are whether there is a magnet or not, that is, if the solenoid is brought closer, the LED light will turn on, which means there is a magnet and vice versa, if the solenoid is kept away, the LED light turns off, which means there is no magnetic field. In the experiment, the effect of the number of turns shows that the more the number of turns, the greater the magnetic field. The third experiment is the effect of current with 3 trials with different current values and the same number of turns, the result is that the greater the current, the greater the magnetic field value. This shows that the results are appropriate and valid and can be used as a physics practicum tool. [ABSTRACT FROM AUTHOR]

In this paper, we investigate properties concerning some recently introduced finite coarse shape invariants—the k-th finite coarse shape group of a pointed topological space and the k-th relative finite coarse shape group of a pointed topological pair. We define the notion of finite coarse shape group sequence of a pointed topological pair X , X 0 , x 0 as an analogue of homotopy and (coarse) shape group sequences and show that for any pointed topological pair, the corresponding finite coarse shape group sequence is a chain. On the other hand, we construct an example of a pointed pair of metric continua whose finite coarse shape group sequence fails to be exact. Finally, using the aforementioned pair of metric continua together with a pointed dyadic solenoid, we show that finite coarse-shape groups, in general, differ from both shape and coarse-shape groups. [ABSTRACT FROM AUTHOR]

Presented here is a theory model based on the beam-envelope approach to determine the global behavior of a charged beam propagating through a high intensity linac with a solenoid channel, namely, the orbital evolution of the root-mean-square beam size in the transverse and longitudinal direction. The model is applied to the Gaussian particle distribution, where the motion of an individual particle is governed by linear focusing/defocusing forces in the solenoid channel and RF fields, except for space-charge forces. In this model, highly nonlinear effects that originated from space-charge forces disappear by averaging over the harmonic motions such as the betatron motion and phase motion in the moving direction and the Gaussian distribution. All particles making up a 3D Gaussian bunch obey the same linear equations of motion where all information of nonlinearity in the space-charge forces and the particle distribution are carried in. The theory is validated using Gaussian macro-particle simulation and one of the widely used photonic integrated circuit codes, TraceWin. As an example, the model is applied to the case of an international fusion materials irradiation facility superconducting linac with solenoid guiding and half wave RF acceleration. The results are compared with results obtained by this model and other two approaches. [ABSTRACT FROM AUTHOR]

Solenoid is the most preferred geometry for MJ class–based HTS-based SMES; however, current carrying capacity is limited by the radial component of magnetic field. Optimization of dimensions is required for reducing the refrigeration cost, cost of 2 G HTS tape, structural support, and cryostat dimensions. A new optimized shape, which looks like a solenoid from the outside but has a different inner radius for each double pancake (DP) coil, is obtained using teaching learning-based optimization (TLBO) for minimum length and 1 MJ stored energy. The structural integrity and the operating current of SMES coil degrade due to high Lorentz force; therefore, stress is also included in optimization process as a constraint. COMSOL along with MATLAB is used for shape optimization. The operating current is increased by reducing the perpendicular component in these novel shapes thereby, reducing the total HTS tape length. These shapes are compared with the optimized perfect solenoid in terms of HTS tape length, stress, and inductance. [ABSTRACT FROM AUTHOR]

The resistance and inductance of an inductor working at high frequencies depend on frequency because of eddy currents caused by the skin and proximity effects. In addition, the stray capacitance among winding coils would give significant influence. This paper proposes an equivalent circuit model which can consider the displacement and eddy currents simultaneously in frequency and time domain. In the proposed circuit model, the capacitance and complex inductance are determined by solving electrostatic and magnetostatic equations with finite element method (FEM). It is shown that the input impedance of an air-core coil is consistent with that computed by FEM at low frequencies. Moreover, the former is shown to be consistent with the measured result. [ABSTRACT FROM AUTHOR]

Solenoid operated valves (SOVs) are critical components in many industrial applications. There has been a continuing interest in the industry to have robust condition monitoring, prognostics and health management tools to support the condition based maintenance and predictive maintenance program for such valves. For critical assets like SOVs, it is of paramount interest to understand why a component might be declared as defective. In such a situation, a first principle-model based approach will always be preferred to a purely data-driven approach, because of its inherent interpretability. Furthermore, first principle-models typically have less free parameters than their data driven counterparts and will require less data to identify their parameters. In this paper, we present the improvement of a first-principle model of alternating current (AC) powered SOVs taking into account two important degradation effects. Using this model, we show that the state of degradation can be estimated from current and input voltage measurement signals on the solenoids. Our method is validated using data from an accelerated life test campaign on 48 identical AC-powered SOVs. [Display omitted] • An electro-mechanical model of AC-powered SOVs is improved. • Methodology to extract three CIs using the improved model and test data is proposed. • Accelerated life test data of 48 valves demonstrate the effectiveness of the CIs. • One CI shows a monotonically increasing trend which is good for prognostics. • Other two CIs are good for shading ring degradation diagnostics. [ABSTRACT FROM AUTHOR]

This paper discusses issues of using superconductors in modern accelerators, such as free-electron laser type, in a radioactive environment. It shows how irradiation damages the subtle structure of superconducting materials, especially 1D and 2D high-temperature superconductors, in which it leads to the creation of nano-sized columnar-type defects. The influence of the radiation-induced structural defects on the current-carrying properties of the superconducting materials is investigated according to a developed energetic description of the capturing process on these defects, acting as pinning centres of magnetic pancake vortices. Various initial positions of the captured vortices are analysed. The influence of the irradiationinduced defects on the current-voltage characteristics is investigated, and the maximum current density is determined as a function of irradiation intensity and such physical parameters as magnetic field, temperature, and nano-defect size. This analysis is therefore of scientific interest and should also be helpful in determining the proper operating conditions of solenoids and other superconducting elements in free-electron laser facilities. [ABSTRACT FROM AUTHOR]

This paper presents a system which consists of a door that unlocks with the help of face recognition and face detection with an attendance manager. The system has two sides of working for better clarification of attendance issue in institutes or workspaces, the two sides of system consist of: outside the door esp32 camera is programmed with face detection and face recognition that helps in unlocking the door and then we have the inside camera which refers to the pre-registered data of person to log the attendance in presence of authority. In this system, a camera captures an image of a person's face and compares it to the registered image in the system's database. If there is a match, the person is identified, and their attendance is recorded. The system can be integrated with a door access control system, allowing the person to enter or exit a room or building based on their identification. To unlock a door using face recognition technology, the system is connected to an electronic solenoid lock that can be activated on meeting certain conditions. When a person's face is recognized, the system sends a signal to the electronic lock to unlock the door. This technology provides a convenient and secure way of managing access to restricted areas, reducing the risk of unauthorized access and ensuring accurate attendance records. [ABSTRACT FROM AUTHOR]

Electrode-pair towed antennas are widely utilized for marine electromagnetic detection, underwater communication, and other purposes. However, the motion-induced noise created by antenna vibrations due to environmental turbulence affects extremely low frequency and super low frequency (ELF/SLF) communications. In this article, we presented a method for detecting the motion-induced noise of electrode-pair towed antennas using helix coil sensors. The equivalent resistance, inductance, capacitance, and conductance (RLCG) transmission model and parameters were derived based on the mirror method of the twisted structure with a shielding layer inside. A water-flow cycling experimental platform was constructed to evaluate two types of antenna sections. Electrode-pair, accelerators, and helix coils sensors signals were sampled and analyzed in time and frequency domain. The comparison results demonstrated that the helix coil sensors achieved a high correlation with the electrode-pair towed antenna in various vibration speeds ranging from 0.7 to 0.9. [ABSTRACT FROM AUTHOR]

The magnetic valve plays a key role in the air-flow weft insertion and injection system of the loom. In order to improve the weaving efficiency of the loom and solve the problem of solenoid valve response lag, an optimization method based on BP neural network prediction of electromagnetic force combined with multi-objective optimization genetic algorithm was proposed. Firstly, in view of the complex change of the magnetic resistance in the magnetic field caused by the change of the armature structure and position of the solenoid valve, which made it difficult to calculate the accurate electromagnetic force through the theoretical model, the BP neural network was used to predict the electromagnetic force of the solenoid valve. Secondly, NSGA-II was used to optimize the preserved BP neural network prediction model and the obtained mathematical model of the armature mass, and the Pareto frontier solution of the electromagnetic force and the armature mass of the solenoid valve was obtained; Finally, the optimal parameter combination was selected according to the standard closest to the original armature quality, and compared with the electromagnetic force of the original structure. The results show that the optimized electromagnetic force increases by 11.5%, but the armature mass decreases by 1%. The simulation experiment also verifies the effectiveness of the optimization method. [ABSTRACT FROM AUTHOR]

The investigation of a pilot operated proportional pressure relief valve is described in this article. Different measurements are performed with a hydraulic test bench under laboratory conditions. A VTVSPA1- 1 amplifier module is used to control the current of the valve's solenoid. The characteristics of the valve are determined as a function of the pressure -- command value of the amplifier -- volume flow rate. The results of the measurements can provide input data for the refinement of the mathematical model of the unit, which will be set up in the future. [ABSTRACT FROM AUTHOR]

Safety and comfort are the two major requirements for the successful implementation of self-driving cars, which are anticipated to constitute the future generation of transportation. To create safe and effective self-driving car trajectories, a novel behavioral decision model is developed. First, a risk field model for driving activities based on vehicle kinematics and Eulerian solenoids is constructed. From there, the principle of least action is applied to produce the best trajectory points. Finally, nine typical unit scenarios are simulated by matlab's driving scenario designer to verify the feasibility of the decision-making algorithm. This study illustrates how an unified operational risk field can efficiently increase intersection passing efficiency while ensuring safety, utilizing the principle of least action. The experimental results show that in the scenario of unprotected left turn and more than 5 vehicles in the intersection, the decision-making model improves the pass rate by 23% compared with the TTI (Time To Intersection) threshold method. [ABSTRACT FROM AUTHOR]

We study the algorithmic content of Pontryagin - van Kampen duality. We prove that the process of dualization is computable in the important cases of compact and locally compact totally disconnected Polish abelian groups. The applications of our main results include solutions to questions of Kihara and Ng about presentations of connected Polish spaces, and an unexpected arithmetical characterisation of direct products of solenoid groups among all Polish groups. [ABSTRACT FROM AUTHOR]

The propellant flow control valves, also referred to as latchable series redundant valves (LSRV's) are essentially used in satellite control systems. Main component of these valves are solenoid bobbins, which composed of four parts, three of which are made of AISI 446 ferritic stainless steel and one part is made of AISI 304L austenitic stainless steel. These parts are joined by electron beam (EB) welding after shrink fitting to form an important component for propellant flow control systems. During dye penetrant (DP) testing of these components after annealing heat treatment, discontinuous cracks were noticed in AISI 446 steel at the inner side of the bobbin. Detailed metallographic and fractographic analysis on the failed component showed a discontinuous crack path circumferentially near the HAZ region of AISI 446 steel. The fracture morphology revealed a complete transgranular cleavage fracture which indicated a brittle mode of failure. Further, AISI 446 raw material was also analyzed along with heat treatment cycle followed in the valve component. [ABSTRACT FROM AUTHOR]

When a recloser detects fault currents in electric power distribution lines, it breaks the line and then restores the line after several fault tests. To check whether fault remains, the recloser performs CO operations (opening the contacts after reclosing them for a while). In this operation, the fault currents flow into the line, potentially causing damage to equipment connected to the line. Therefore, reducing the current-carrying time during the fault test is desirable, but this reduction is difficult because of the slow actuation mechanism of reclosers. In this article, a novel actuation mechanism combining a permanent magnetic actuator (PMA) and a solenoid actuator (SA) is proposed. During the CO operations for the fault tests, the proposed mechanism can rapidly break the closed contacts by hitting the moving contact with the SA. To increase the energy efficiency of the actuation mechanism, a distinctive PMA driving method is also proposed; it weakens the strong holding force of the PMA using assistive magneto-motive force (MMF). The structure and configuration of the proposed mechanism are explained. The performance of the mechanism and the effectiveness of the driving method are studied through cosimulations. Finally, a prototype is developed, and its practicality is verified through experiments. [ABSTRACT FROM AUTHOR]

In this article, a 2.5m five-stage inductive power transfer (IPT) system based on domino cylindrical solenoid coupler (CSC) compensated, respectively, in layers is proposed. The system is considered to be used as 220 kV post insulators application, transferring power for sensors and measuring instruments of smart grids. The distributed series compensation method is applied to double-layer CSC. Compared with the two types of parallel schemes, this method can significantly reduce the current of the main circuit. Compared with the concentrated series compensation method, this method can effectively reduce the resistance caused by the stray capacitance. The interaction between the post insulator and the magnetic coupling structure is analyzed. The circuit model of the system with constant voltage output characteristics is analyzed. A prototype with a maximum efficiency of 66.7% is built. When the power is transferred to a larger value of 77.8W, the efficiency can still reach 62%. Comparing with previous works, the wireless distance is extended while the efficiency is improved. [ABSTRACT FROM AUTHOR]

The aim of this study was to design operation methods for three-stage coil gun experiments and to fabricate and compare prototypes of control systems using these methods. Two methods are proposed: (1) recognizing the position of a projectile using a photointerrupter and (2) operating a control circuit to supply power to a silicon-controlled rectifier when the projectile reaches an intended position by registering the delay time between coil gun operations. The distance between the projectile and the solenoid coil during a coil gun operation is a key design factor. For the multi-stage coil gun manufactured in this study, the discharge time must be determined according to the position of the projectile, which moves at high velocity. Therefore, the selected method should have minimal operation error and allow the circuit to be easily used according to the coil gun stage and configuration. This study compares the prototypes of coil gun discharge circuits that were fabricated based on the proposed methods by applying them to three-stage coil guns and measuring their velocities. The findings of this study could be used to suggest design methods for experimental models for coil guns with fewer stages according to the final velocity and coil gun stage to be manufactured. [ABSTRACT FROM AUTHOR]

To improve the dynamic response speed of high-speed solenoid valves in electric fuel injection systems of marine diesel engines, a numerical simulation model of the solenoid valve is described in this paper. The accuracy of the simulation model was verified on the test bed of the solenoid valve. The effect of the punch position and the size of the dynamic response of the solenoid valve were investigated by using the distribution law of the electromagnetic force in the armature. The results of the test showed that armature drilling in the inter-yoke zone can optimize the solenoid closing response time, but it has little impact on the solenoid opening response time. From this rule, two groove schemes were further designed. Through comparison and calculation, it can be concluded that the fan groove scheme is better than the trapezoidal groove scheme, and that the opening and closing response times of the solenoid valve should be targeted in order to multi-target optimize the fan groove geometric parameters and the armature thickness. The results show that after optimization, the weight of the motion part is reduced by 21.6%, the opening response time of the solenoid valve is reduced by 11.1%, and the closing response time is reduced by 30.0%. While reducing the oil film damping of the armature motion, the overall dynamic response characteristics of the solenoid valve are improved. [ABSTRACT FROM AUTHOR]

The practical implementation and parameterization of a model for estimating the magnetic force of valve solenoids involving a hysteresis model are evaluated. In a first step, popular approaches for modeling the force hysteresis of valve actuators are compared, followed by a description of the test bench used and the valve investigated. Next, the experimental procedure as well as the recorded data are described and discussed. Finally, a phenomenological modeling approach of force hysteresis is presented. The advantages and limitations are demonstrated and discussed using measured data. [ABSTRACT FROM AUTHOR]

In the field of eddy‐current testing (ECT), most studies on detection probes are primarily based on circular solenoid coils; related research on rectangular spiral coils is rare. In this study, an analytical model of the mutual inductance (MI) between two coplanar rectangular spiral coils was developed in which the two coplanar rectangular spiral coils were placed above a conductive plate. The MI calculation does not need to consider the thickness of the coils, which is consistent with the actual situation of the printed circuit boards (PCB)‐based spiral coils, and simplifies the multi‐turn rectangular spiral coil into a set of concentric single‐turn coils. Two experimental setups were constructed to verify the analytical model and they were used to detect defects in the aluminium plate. The experimental results indicate that the analytical model can be used to evaluate the performance of ECT probes using PCB‐based spiral coils, through the geometrical dimensions of the coils, centre distance and lift‐off, and so forth. Compared with traditional methods, this method can still obtain satisfactory calculation accuracy after ignoring thickness parameters. The analytical model is also an effective tool to aid in the design of detection probes and optimisation of related parameters. [ABSTRACT FROM AUTHOR]

A homoclinic class is the closure of the transverse intersection points of the stable and unstable manifolds of a hyperbolic periodic orbit. In this paper, we prove, using the techniques presented in [1], that the Plykin and the Solenoid attractors are a homoclinic class. [ABSTRACT FROM AUTHOR]

The acoustic pulse emitted from the Bragg peak of a laser-accelerated proton bunch focused into water has recently enabled the reconstruction of the bunch energy distribution. By adding three ultrasonic transducers and implementing a fast data analysis of the filtered raw signals, I-BEAT (Ion-Bunch Energy Acoustic Tracing) 3D now provides the mean bunch energy and absolute lateral bunch position in real-time and for individual bunches. Relative changes in energy spread and lateral bunch size can also be monitored. Our experiments at DRACO with proton bunch energies between 10 and 30 MeV reveal sub-MeV and sub-mm resolution. In addition to this 3D bunch information, the signal strength correlates also with the absolute bunch particle number. [ABSTRACT FROM AUTHOR]

Numerous studies are conducted to improve the flow in the boundary layer to ensure laminar flow and in particular to increase flight safety. A new solution used to improve the laminar flow is the plasma actuator. The classic configuration of DBD plasma actuators is commonly used with the asymmetric electrode system. The manuscript describes the results of tests with a plasma actuator. Experimental tests were carried out on the built model of the wing with the SD 7003 profile, a plasma actuator was mounted on the upper surface. In contrast to the commonly used solution with solid tape copper electrodes, the novelty in the described research in the manuscript is the use of a large GND electrode (covering 70% of the upper surface of the wing) and a HV mesh electrode. The use of a plasma actuator on the upper surface of the wing affects the air flow in the boundary layer as a result of air ionization. The tests were carried out for a supply voltage from V = 7.0 kV to 12 kV and Reynolds number, Re = 87500 to 240000, flow velocity during the tests in the tunnel was in the range of U = 5-15 m/s and the angle of attack α = 5-15 degrees. On the basis of the results experimental tests, the percentage change in the lift coefficient was calculated for the switched on and off DBD system. The obtained results indicate a maximum 17% increase in the lift coefficient for the plasma actuator activated for air flow U = 5 m/s and angle of attack α = 5 degrees. In the remaining configurations, changes in the lift coefficient amounted to 4%. [ABSTRACT FROM AUTHOR]

Let G be a torsion-free abelian group of rank two and let φ be an endomorphism of G, called a rank-two solenoidal endomorphism. Then it is represented by a 2 × 2-matrix Mφ with rational entries. The purpose of this article is to prove the following: The group, coker(φ), of the cokernut of φ is finite if and only if Mφ is nonsingular, and if it is so, then we give an explicit formula for the order of coker(φ), [G : im(φ)], in terms of p-adic absolute values of the determinant of Mφ. Since G is abelian, the Reidemeister number of φ is equal to the order of the cokernut of id − φ and, when it is finite, it is equal to the number of fixed points of the Pontryagin dual φ of φ. Thereby, we solve completely the problem raised in [16] of finding the possible sequences of periodic point counts for all endomorphisms of the rank-two solenoids. [ABSTRACT FROM AUTHOR]

Solenoid coils with grounded ends positioned on the dielectric window were proposed and numerically studied to reduce the capacitive coupling in conventional inductively coupled plasma (ICP) sources. The capacitive coupling between the plasma and the coils was subsequently suppressed, leading to a significant reduction of the window erosion. To understand the plasma characteristics and the advantages of this configuration, the discharges by the solenoid coil were modeled and compared with a conventional planar coil ICP discharge. The solenoid coil could generate a plasma with higher density than the planar coil under the same absorbed power. The ratio of inductive to capacitive heating power of the solenoid coil was more than one magnitude higher than that of the planar ICP source. The voltage drop on the dielectric window under the solenoid coil was significantly reduced, which was attributed to a potential shielding effect of the grounded end of the radio frequency coil. [ABSTRACT FROM AUTHOR]

This article presents a novel constant air-gap solenoid (CAS) actuator design that can perform accurate and wide-bandwidth closed-loop position control with two fused self-sensed plunger measurements. The recently patented CAS actuator is experimentally validated to be the first electromagnetic actuator with the ability to simultaneously produce two plunger position measurements with complementary bandwidth characteristics. First, a variable reluctance differential solenoid transducer (VRDST) is converted into a stacked CAS actuator through minor geometry modifications. Next, two complementary self-sensing methods that are based on inductance and back electromotive force (BEMF) are selected. Then, a complementary filter design is proposed to fuse the inductance- and BEMF-based self-sensing methods. Afterward, the design and fabrication of the prototype CAS actuator and the experimental setup are discussed. The experimental setup is then used to characterize the prototype CAS actuator and observe the performance of the individual self-sensing methods. Finally, the fused measurement is used for feedback in closed-loop position control. The closed-loop position control experiments show that the self-sensed feedback performs comparably with a dedicated high-end laser vibrometer. Furthermore, the results show that the sensor fusion output performs better than the individual self-sensing methods. [ABSTRACT FROM AUTHOR]

In phase-contrast magnetic resonance imaging (PC-MRI), spin velocity contributes to the phase measured at each voxel. Therefore, estimating velocity from potentially wrapped phase measurements is the task of solving a system of noisy congruence equations. We propose Phase Recovery from Multiple Wrapped Measurements (PRoM) as a fast, approximate maximum likelihood estimator of velocity from multi-coil data with possible amplitude attenuation due to dephasing. The estimator can recover the fullest possible extent of unambiguous velocities, which can greatly exceed twice the highest venc. The estimator uses all pairwise phase differences and the inherent correlations among them to minimize the estimation error. Correlations are directly estimated from multi-coil data without requiring knowledge of coil sensitivity maps, dephasing factors, or the actual per-voxel signal-to-noise ratio. Derivation of the estimator yields explicit probabilities of unwrapping errors and the probability distribution for the velocity estimate; this, in turn, allows for optimized design of the phase-encoded acquisition. These probabilities are also incorporated into spatial post-processing to further mitigate wrapping errors. Simulation, phantom, and in vivo results for three-point PC-MRI acquisitions validate the benefits of reduced estimation error, increased recovered velocity range, optimized acquisition, and fast computation. A phantom study at 1.5T demonstrates 48.5% decrease in root mean squared error using PRoM with post-processing versus a conventional “dual-venc” technique. Simulation and 3T in vivo results likewise demonstrate the proposed benefits. [ABSTRACT FROM AUTHOR]

A solenoid lens has been developed for ultrafast electron diffraction experiments using electron beams with an energy of several MeV. A method for determining the mismatch between the positions of the geometric and magnetic centers of the lens has been elaborated. This method is based on measuring the radial dependence of the longitudinal magnetic field. [ABSTRACT FROM AUTHOR]

The engineering part of the GLOBSYS code is presented, and the parameters of the Globus-3 facility, which is a development of the Globus program, are analyzed. The facility is primarily designed to provide a long pulse, a large toroidal magnetic field and strong heating. The concepts of searching for Globus-3 parameters under physical and engineering limitations are described. Obviously that reliable confinement and a large part of noninductive current are necessary to ensure existence of a plasma for a long time. Engineering constraints are involved in the choice of parameters in a more complex way: in some cases, it is overheating of the coils, in other cases, it is the total power supply, or the limit on the flux provided by the ohmic solenoid, or the strength of the constructions. The parameters of the Globus-3 spherical tokamak were preliminarily selected for the cases of a "warm" copper EMS (Electromagnetic system) and the EMS precooled to liquid nitrogen temperature. The exceeding of the duration of the plasma current plateau Δtplateau over the characteristic settling time of the plasma profiles τL/R was chosen as the key condition. At values of the toroidal magnetic field Bt0 = 3 T, the condition Δtplateau > τL/R cannot be attained even for precooled EMS. At Bt0 = 2 T, only options with precooled EMS can be considered acceptable, but the facility dimensions are fairly large. For the field Bt0 = 1.5 T, the options with "warm" EMS correspond to the duration of the plasma current plateau ~3 s (Δtplateau/τL/R ~ 1–1.5). In the case of precooled EMS, the duration of the plateau can increase to 12–13 s (Δtplateau/τL/R ~ 5). In the latter case, as a basis for further development of the Globus-3 facility, options with the following geometric dimensions are reasonable: R0 ~ 0.6–0.7 m, a ~ 0.35–0.4 m, А ≤ 1.7–1.8, k95 ~ 1.7–1.8. The minimum allowable value of the plasma current under the condition of effective absorption of the input power of neutral injection has been calculated. In the Globus-3 facility, Ip ≈ 0.8 MA was chosen as the base value. [ABSTRACT FROM AUTHOR]

Inductive power transmission has been applied in industries, such as electric vehicles, consumer electronics and biomedical fields. However, there is a long-term key problem in this field that has not been solved. This is the adverse effect of the parasitic capacitance of the coil, which will cause the change of the coil inductance, the reduction of the quality factor and the reduction of efficiency. Especially in the field of long-distance wireless power transmission. The existing technologies all adopt the scheme of sacrificing volume in exchange for the quality factor of the coil. As a result, the volume of the system is very large, and the quality factor of the coil is still not high enough because the influence of parasitic capacitance has not been completely eliminated. Here, we found the solution. Connect compensation capacitors in series to the coil sections to short-circuit the parasitic capacitance and reduce its loss. The designed system has a diameter of 502 mm and a thickness of 22 mm, which can transmit 115.2 W of power within a distance of two meters with an efficiency of 29%. [ABSTRACT FROM AUTHOR]

The detection of surface cracks at or close to sample edges is a challenging problem because the interaction of the eddy current with the sample edge can make it difficult to distinguish changes in the eddy current signal due to a defect. Samples with poor electrical conductivity such as titanium alloys used extensively in aerospace applications can be more difficult to inspect due to the low amplitude eddy currents induced in them and increased electromagnetic skin depths due to lower electrical conductivity. As fatigue surface cracks or manufacturing surface defects can often occur close to edges, the challenges of detecting small defects close to sample edges is an important research area to address. High-frequency eddy currents of over 10 MHz are used in a transmit-receive configuration using two solenoid type coils adjacent to each other. While conventional eddy current sensors are commonly designed for operating at frequencies into the low MHz region, the supporting electronics here will be positioned immediately behind the coils to improve electrical stability and reduce induced noise. The magnitude and phase of the voltage on transmit and receiver coils are measured, and finite element modelling is used to validate the experimental measurements and gain insight into the system behaviour. Small defects of down to 1 mm are easily detected, on the edge and at the corner of a titanium alloy sample with excellent signal-to-noise. [ABSTRACT FROM AUTHOR]

In gapped inductors, the fringing field of the air gaps causes additional eddy current losses in the windings and an increase of the inductance. Since this impact of the fringing field is very significant, calculating the additional eddy current losses and the inductance increase is important in the design of inductors. This article proposes analytical formulas to accurately calculate the inductance and the additional eddy current losses in gapped inductors with solid round wire and Litz wire windings. The analytical formulas are verified by measurements, showing that the proposed models are accurate over a wide-frequency range. [ABSTRACT FROM AUTHOR]

The development of radio-frequency integrated circuits (RF-IC) necessitates higher requirements for the size of microtransformers. This paper describes millimeter-scale 3D transformers in millimeter-scale, solenoidal, and toroidal transformers manufactured using Micro-electromechanical Systems (MEMS). Two through-silicon via (TSV) copper coils with a high aspect ratio are precisely interleaved on a reserved air core (magnet core cavity) with a vertical height of over 1 mm because of the thickness of the substrate, which increases the performance while reducing the footprint. The effects of the wire width, coil turns, magnetic core, and substrate on the performance of the two transformers are discussed through numerical simulations. When an air core is present, solenoidal transformers are better than toroidal transformers in terms of performance and footprint; however, the gap decreases when the size is reduced. Additionally, the magnetic core significantly improves the performance of the toroidal transformer compared to that of the solenoid. Thus, the toroidal transformer has a higher potential for further size reduction. The two types of transformers were then manufactured completely using MEMS and electroplating. This paper discusses the influence of various parameters on millimeter-scale 3D transformers and realizes processing in silicon, which provides the foundation for integrating transformers in a chip. [ABSTRACT FROM AUTHOR]

Objective: The current distribution of the matrix gradient coil can be optimized via matrix gradient coil modeling to reduce the Lorentz force on individual coil elements. Two different modeling approaches are adopted, and their respective characteristics are summarized. Methods: The magnetic field at each coil element is calculated. Then, the Lorentz force, torque, and deformation of the energized coil element in the magnetic field are derived. Two modeling approaches for matrix gradient coil, namely, optimizing coil element current (OCEC) modeling and optimizing coil element Lorentz force (OCEF) modeling, are proposed to reduce the Lorentz force on individual coil elements. The characteristics of different modeling approaches are compared by analyzing the influence of the weighting factor on the performance of the coil system. The current, Lorentz force, torque, and deformation results calculated via different modeling approaches are also compared. Results: Coil element magnetic fields are much weaker than the main magnetic field, and their effect can be ignored. Matrix gradient coil modeling with different regularization terms can help to decrease the current and Lorentz force of coil elements. The performance of the coil system calculated via different modeling approaches is similar when suitable weighting factors are adopted. The two modeling approaches, OCEC and OCEF, can better reduce the maximum current and Lorentz force on individual coil elements compared with the traditional modeling approach. Conclusions: Different modeling approaches can help to optimize the current distribution of coil elements and satisfy various requirements while maintaining the performance of the coil system. [ABSTRACT FROM AUTHOR]

The paper presents an overview of the economic efficiency for linear drive with solenoid coupling. Moreover, the linear drive with solenoid coupling is also a pneumatic device. Thereby in this article, we are studying two pneumatic and one electro-pneumatic installation, which contains the linear drive with solenoid coupling. The first pneumatic circuit contains the following devices: compressed air supply, start-up valve with filter control valve, 4/2-way valve with spring, throttle valves, linear drive with solenoid coupling (LD 1-1). The second pneumatic circuit contains the following components: linear drives, throttle valves, 5/2-way valve, air service unit, compressed air supply. The last circuit which is actually an electro-hydraulic circuit contains the following components: compressed air supply, 5/2-way solenoid valve with spring, linear drive with solenoid coupling (LD 3-1), relays, valves solenoid and magnetic proximity switch. [ABSTRACT FROM AUTHOR]

It is important to analytically and accurately calculate the self-inductance of the primary and secondary coils and the mutual inductance between them, in order for the optimization algorithm of the Inductive Power Transmission (IPT) system. In this paper, the inductance calculation methods used in the IPT designs at different power levels are examined. The performances of these methods have been evaluated according to the experimental results of these IPTs using rectangular coil pairs. Inductance results were obtained with Finite Element Analysis (FEA) for IPTs without experimental results. Accordingly, a 120 W IPT has been designed to be used for wireless charging of the Electric bicycle (e-bike). Rectangular spiral coil pair with 75 mm distance between them was fabricated according to the design result. Analytical and experimental inductance values are compatible with each other for the optimal IPT design. The efficiency between the DC power supply to the load has been achieved as 92.1672% in approximate load conditions. [ABSTRACT FROM AUTHOR]

Examples of Fell algebras with compact spectrum and trivial Dixmier-Douady invariant are constructed to illustrate differences with the case of continuous-trace C^*-algebras. At the level of the spectrum, this translates to only assuming the spectrum is locally Hausdorff (rather than Hausdorff). The existence of (full) projections is the fundamental question considered. The class of Fell algebras studied here arises naturally in the study of Wieler solenoids and applications to dynamical systems will be discussed in a separate paper. [ABSTRACT FROM AUTHOR]

The presented experimental method enables the study of the dynamics of a domain wall (DW) moving in bistable microwire in a region of rapidly changing magnetic field. DW velocity versus DW position dependence is obtained in this experiment. Measurements were carried out on Fe77.5Si15B7.5 microwire with strong unidirectional effect in DW propagation. The propagating DW is forced to change its parameters in a very short time, which results in the velocity increasing above its equilibrium value after the DW passes the region of rapid increase in magnetic field. In order to interpret the observed experimental behavior, a simple theoretical model was proposed. Comparison of experimental and model dependences produced a high value of DW inertial mass, indicating that the DW area was much larger than the cross-sectional area of the microwire. Another interesting conclusion was that a DW with stronger damping (shorter wall) does not have a lower value of inertial mass. [ABSTRACT FROM AUTHOR]

A variety of needle-motion profiles are used in diesel injectors. However, it is unclear what the underlying mechanism is to determine the needle-motion profiles and how they affect the spray dynamics. It has been of significant interest to examine how the spray dynamics will change if only altering the needle valve opening speed or closing speed while all other parameters are kept the same. The different needle-motion profiles were obtained using a piezo nozzle (Nozzle #P) and a solenoid nozzle (Nozzle #S), which have identical nozzle geometry. By utilizing the X-ray imaging technique, it was observed that the average needle valve speed of Nozzle #P was 51% higher at the opening stage but 17% lower at the closing stage than Nozzle #S. When the needle valve lift is low (approximately 200 μ m ), the needle valve opening speed has a crucial effect on spray dynamics. The faster needle valve opening of Nozzle #P results in a 42% larger spray spreading angle and 34% lower spray velocity at the downstream field. The spray dynamics may be controllable by properly designing the needle-motion profiles in the scenarios of the low needle lifts. However, when the needle valve is sufficiently open (approximately over 200 μ m ), almost identical spray characteristics were observed regardless of the needle-motion profiles. [ABSTRACT FROM AUTHOR]