Magnetic Levitation Research Articles

Efficient loading of cesium atoms in a magnetic levitated dimple trap

We report a detailed study of magnetically levitated loading of ultracold 133Cs atoms in a dimple trap. The atomic sample was produced in a combined red-detuned optical dipole trap and dimple trap formed by two small waist beams crossing a horizontal plane. The magnetic levitation for the 133Cs atoms forms an effective potential for a large number of atoms in a high spatial density. Dependence of the number of atoms loaded and trapped in the dimple trap on the magnetic field gradient and bias field is in good agreement with the theoretical analysis. This method has been widely used to obtain the Bose–Einstein condensation atoms for many atomic species.

Ground testing of Al-polyurethane shape memory polymer sail material under pulsed light exposure

This article presents a study on design and testing of space sails using Al-polyurethane Shape memory polymer. The properties of the polymer are simulated and tested in the design phase, and the results are compared with the fabricated sail, which is considered nominal. The efficiency of the polyurethane sail is found to be approximately 86.5%. The controllability of the sail is enhanced using a heating system that uses light rays to heat the polymer at specific control spots. The relative deflection at these spots causes a deviation in solar momentum, resulting in a controlled displacement of the sail. This control system is found to be 42% more efficient than conventional vane-type deflection systems. The paper also presents the fabrication of a ground testing apparatus designed to test the sail specimen in laboratory conditions. The apparatus is capable of producing a vacuum chamber pressure up to −400 mm/Hg and includes a magnetic levitation platform with strong permanent magnets to neglect local gravitational effects. The platform provides support for fixing the solar sail frame made from carbon fiber composite material. The testing apparatus consists of a 1000-W halogen light source with intensity ranges of approximately 200,000 lux. Sail material with a reflective surface is exposed to controlled luminance under vacuum conditions to measure the deflection of the sail. Deflection values are recorded by means of a resistance type strain gauge and strain indicator arrangement. Plotting deflections with time period gives the acceleration of the sail inside the test apparatus. A coolant chamber with a ceramic base is also provided to reduce temperature effects inside the vacuum chamber. In conclusion, this study presents a promising approach for the design and testing of solar sails using shape memory polymer and a ground testing apparatus. The results of this research can contribute to the development of more efficient and versatile solar sail technology for fuel-free aerospace propulsion.

Numerical and experimental performance study of magnetic levitation energy harvester with magnetic liquid for low-power-device’s energy storage

Energy harvesting is an emerging technology that uses ambient vibrations to generate electricity. The harvesting energy from vibrating environments can be stored by batteries to supply low-power devices. This paper presents a new structure of magnetic levitation energy harvester (MLEH) for low-power-device’s energy storage, which uses magnetic liquid to improve energy conversion efficiency and broaden bandwidth. Its working principle, structure and analysis model are introduced in detail. Specifically, the mathematical model of the energy harvester system is established by harmonic balance method. The nonlinear stiffness of the magnetic spring and damping characteristics of the system are analyzed by experiments. In addition, four prototype energy harvesters are designed for different magnet distances and magnet numbers. Finally, the experimental results are compared with the numerical results of dynamic simulation to verify the accuracy of the proposed model. Performance improvements of the energy harvester with magnetic liquid are evaluated by defining bandwidth growth rate and normalized power density. The experimental results show that when the wire diameter in the coil is 0.44 mm, the peak power of the energy harvester with magnetic liquid is 1.64 times greater than that of the energy harvester without magnetic liquid, the normalized power density can reach 183.39 μW⋅cm−3⋅g−2, and the bandwidth is widened by 65%.

The Society of Thoracic Surgeons Intermacs 2023 Annual Report: Focus on Magnetically Levitated Devices

The 14th Annual Report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) describes outcomes of 27,493 patients with a continuous-flow left ventricular assist device (LVAD) from the past decade (2013-2022). In 2022, 2517 primary LVADs were implanted, of which 2512 (99.8%) were fully magnetically levitated (Mag-Lev) devices. This shift to nearly exclusive use of a Mag-Lev device led us to examine its outcomes compared with contemporary (2018-2022) and historical (2013-2017) non-Mag-Lev cohorts. Patients supported by a Mag-Lev device (n= 10,920) had a higher 1- and 5-year survival of 86% (vs 79% and 81%, P < .0001) and 64% (vs 44% and 44%, P < .0001), respectively, than those receiving non-Mag-Lev devices during the contemporary and historical eras. Over 5 years, freedom from gastrointestinal bleeding (72% vs 60%, P < .0001), stroke (87% vs 67%, P < .0001), and device malfunction/pump thrombus (83% vs 54%, P < .0001), but not device-related infection (61% vs 64%, P= .93), was higher with Mag-Lev devices compared with non-Mag-Lev support during the contemporary era. In this large primacy cohort of real-world patients with advanced heart failure, this report underscores markedimprovements in short- and intermediate-term survival and reduction of adverse events with a contemporary Mag-Lev LVAD.

Abstract 16713: Pre-Clinical 30-day Survival Results of the BiVACOR TAH

Introduction: The BiVACOR Total Artificial Heart (TAH) replaces the failing heart with a durable and physiologically adaptive pump, which combines magnetic levitation and rotary blood pump technology. The pump has large clearances to minimize shear stress, generates pulse pressure via cyclic changes in pump speed, and modulates total outflow based on physiological conditions. A single rotor design enables a small pump size. Aim: Primary endpoint was survival at 30 days with normal end-organ function and absence of device related thromboembolism at necropsy. Methods: Five calves (82 - 108 kg) were implanted with the BiVACOR TAH and underwent continuous hemodynamic monitoring for 30 days. The pumps ability to generate a pulse pressure, balance outflow to the systemic and pulmonary circulations and to increase outflow in response to increased physical activity was assessed. Hemocompatibility and end-organ function were routinely monitored. Necropsy was performed on day 30 to evaluate for evidence of thromboembolism and end organ damage. Explanted pumps were examined. Results: All five calves survived to 30 days with normal end-organ function. Stable hemodynamics were achieved with normal pressures in the aorta and left and right atrium (MAP 111 ± 6 mmHg, CVP 12 ± 5 mmHg, LAP of 20 +/- 5 mmHg). Average estimated pump output was 12 ± 2 L/min with average pulse pressure of 30 mmHg. Pump output increased during changes in daily physiological condition (10 to 14 L/min). No device-related thromboembolism or other end organ pathologies were detected at necropsy. All explanted pumps were free of internal pump thrombus. Hemocompatibility was demonstrated (pfHb 4.34 ± 0.74 mg/dL). Bypass time decreased by 34 minutes over the entire study cohort. Conclusion: The BiVACOR TAH demonstrates normal hemodynamics including left/right balance. Pump design allows for a normal pulse pressure, increased pump output in response to exercise, and excellent hemocompatibility without device-related thromboembolism. Operative time markedly improves with surgeon experience. The small pump size may expand the use of TAH to smaller patients. This device may address the need for select patients with advanced heart failure who require biventricular support.

Domain structure ordering and magnetic property enhancement of containerlessly processed quaternary Fe-Mo-Ni-Cr alloy

Quaternary Fe-20 %Mo-12 %Ni-6 %Cr alloy with various composite magnetic structures was fabricated through electromagnetic levitation (EML) coupled with multi-mode quenching techniques. The magnetic domain distributions were characterized and related to the macro/micro-magnetic properties of this containerlessly processed alloy. Under EML condition, nano-scale lamellar (αFe) + Fe2Mo eutectoid structures with completely disordered magnetic domains were formed at small undercoolings. But the eutectoid morphology became anomalous and a ferromagnetic (αFe) single-phase zone with clear stripe domains appeared as undercooling increased, resulting in the obvious improvement of saturation magnetization, coercivity and residual magnetization. The (αFe) + Fe2Mo eutectoid structures were entirely suppressed by multiple quenching processes to secure (αFe) single-phase microstructures with ordered domain distributions including the stripe domains with grain boundary contrast, the maze domains with developed branches and their coexistent mixtures. These magnetic structures displayed much higher saturation magnetization, much lower coercivity and almost unchanged residual magnetization as compared with the highly undercooled alloy at EML state, indicating that the soft magnetic property of this alloy was significantly enhanced after rapid quenching. Moreover, the spin distributions and atomic magnetic moments of two constituent phases were analyzed by first-principle calculations, which were in good accordance with the experimental results.

Stabilization With Prescribed Instant for High-Order Integrator Systems.

This article develops a new controller design approach to stabilize system states onto the equilibrium at an arbitrarily selected time instant irrespective of the initial system states and parameters. By the stabilization approach, the actual convergence time (not the bound of actual convergence time) is independent of the initial value of system states. This feature differentiates our proposed prescribed-instant stability from conventional fixed, predefined, and prescribed time stability. In this work, we propose the controller design method for the prescribed-instant stability of n-order integrator systems. The proposed control is bounded and can gradually go to zero at an arbitrarily selected time instant, at which the system states reach zero simultaneously. This special stability of the controlled system is analyzed by reduction to absurdity. In simulations, an example of comparison with frequently used prescribed-time control is presented to show the difference. Moreover, the proposed stabilization method is validated by a magnetic suspension system with matched disturbances.

Synchronous Vibration Force Suppression of Magnetically Suspended CMG Based on Modified Double SOGI-FLL

The mass imbalance of the rotor will produce the synchronous vibration force that is transmitted to the magnetically suspended control moment gyroscope (MSCMG) through the magnetic levitation stator, which affects the imaging performance of the satellite. The suppression of the synchronous vibration force needs the speed signal. In order to solve the synchronous vibration force of the MSCMG when the speed measurement sensor fails, this paper proposed an modified double second-order generalized integral frequency-locked loop (SOGI-FLL) method, which uses the frequency of the disturbance signal generated through the mass imbalance of the rotor to adaptively estimate the rotor speed and suppress the synchronous vibration force generated by the active magnetic bearing system. The phase compensation is introduced to ensure the stability of the system in full frequency band. The electromagnetic force is directly used as the input signal of the control algorithm to achieve zero magnetic force control. Simulation and experimental are carried out, and the results are given to prove that the algorithm proposed in this paper can accurately estimate the rotation speed and achieve the vibration force suppression in the full rotation speed range. It is of great significance for the high-precision control of the active magnetic bearing rotor system.

Variable speed sliding mode control of magnetic suspension linear synchronous motor based on feedback linearization

Variable speed sliding mode control of magnetic suspension linear synchronous motor based on feedback linearization

Design and Optimization of a New Type of Magnetic Suspension Vibration Absorber for Marine Engineering

The magnetic suspension damper, which is based on magnetic suspension technology, is receiving more and more attention from academics as active–passive hybrid damping technology develops. A new symmetric magnetic suspension structure is constructed in this study, and the accuracy of the simulation findings is confirmed by contrasting the output from finite element simulation with the theoretical formulations. On the basis of this, how the structure, size, and material of the electromagnet and armature affect the magnetic flux density, electromagnetic force, and suspension force is investigated. The structure optimization of the electromagnet and armature was performed in accordance with the simulation results, and a new symmetric magnetic suspension structure was produced. The results of the simulation demonstrate that DT4(electrical pure iron) is the ideal material for armatures and electromagnets. The reinforcing ring construction can be built up by the armature to increase suspension force. The suspension force output by the armature will be greatly increased when the size and placement of the reinforcing ring structure are right. The system stiffness adjustment range will expand at this point, enhancing the magnetic suspension damper’s functionality. This study offers novel perspectives for designing structures that reduce vibration and noise in various projects and serves as a guide to constructing magnetic suspension dampers.

Yawing stability and manipulative approach design for maglev car based on active disturbance rejection control

AbstractIn the present work, to realize the stable static suspension of a new type of electrodynamic wheel (EDW) magnetic levitation (maglev) car without track constraints on the conductor plate. Design and analysis of the active disturbance rejection control and explicit complementary filter (ADRC‐ECF) have been presented to solve the maglev car's yaw angle disturbance rejection under low lateral damping characteristics. Simple and efficient ECF helps to filter the high and low frequency noise generated by EDWs when rotating at high speed, to obtain accurate data in real‐time. Design and build the hardware control system for maglev car, and conduct experimental comparisons with PID controller to verify the effectiveness of suppressing yaw angle disturbances. Based on simulation and experimental results, it is shown that both PID and ADRC‐ECF can improve the stable yaw angle convergence of maglev car under external disturbances. However, ADRC performs better in resisting disturbances than PID and can achieve more accurate fixed angle steering. This paper is the first attempt to control maglev car on a trackless conductor plate for precise steering and anti‐disturbance, which is anticipated to have some reference significance in this field.

Unary Adsorption Equilibria of Hydrogen, Nitrogen, and Carbon Dioxide on Y-Type Zeolites at Temperatures from 298 to 393 K and at Pressures up to 3 MPa.

The equilibrium adsorption of CO2, N2, and H2 on commercially available Zeolite H-Y, Na-Y, and cation-exchanged NaTMA-Y was measured up to 3 MPa at 298.15, 313.15, 333.15, 353.15, and 393.15 K gravimetrically using a magnetic suspension balance. The chemical and textural characterization of the materials was carried out by thermogravimetric analysis, helium gravimetry, and N2 (77 K) physisorption. We report the excess and net isotherms as measured and estimates of the absolute adsorption isotherms. The latter are modeled using the simplified statistical isotherm (SSI) model to evaluate adsorbate-adsorbent interactions and parametrize the data for process modeling. When reported per unit volume of zeolite supercage, the SSI model indicates that the saturation capacity for a given gas takes the same value for the three adsorbents. The Henry's constants predicted by the model show a strong effect of the cation on the affinity of each adsorbate.

Magnetorheological characterization of oil-in-oil magnetic Pickering emulsions

A magnetic Pickering emulsion is a type of emulsion stabilized by magnetic nanoparticles that accumulate at the droplet interface. This makes the emulsion easy to control using an external magnetic field, which, in turn, makes it useful in many applications. Research and development in this field are ongoing, but regardless of the application, control of the formation process is necessary. Rheological measurements are one of techniques used for evaluating the internal structure and stability of emulsions. The main focus of the current research is to investigate the magnetorheological effect of the rarely tested oil-in-oil (O/O) magnetic Pickering emulsions and compare them with better-characterized oil-based magnetic fluids.The magnetoviscous effect typically occurs when magnetic nanoparticles or magnetic Pickering emulsions align with the magnetic field, and this effect depends mainly on the internal structure, such as the size and shape of the particles and droplets. The experimental results indicate that the magnetic emulsion fabricated utilizing ultrasound and an additional electric field exhibits higher dynamic yield stress as a function of the magnetic field compared with the partially covered droplets. This suggests that the stable emulsion becomes a more rigid system and is more resistant to deformation when a magnetic field is applied. Besides that, the magnetoviscous effect of the magnetic emulsions was lower compared with that of magnetic suspensions with the same mass fraction of magnetic nanoparticles.

Parametric Reconstruction and State Observation in a Maglev System Via I&amp;I

In this work, the principle of Immersion and Invariance (I&amp;I) is used in the design of an observer/estimator for a closed-loop magnetic levitation system in order to reconstruct the magnetic levitator speed, the internal resistance of the coil and the mass of the levitating ball. By relying on Lyapunov function theory and analysis around a neighborhood of the operation point of the closed-loop dynamics, the stability and convergence of the observed states and estimated parameters to actual ones are guaranteed. Experimental results are shown to demonstrate the effectiveness of the proposed method.

Observation and control of hybrid spin-wave-Meissner-current transport modes.

Superconductors are materials with zero electrical resistivity and the ability to expel magnetic fields, which is known as the Meissner effect. Their dissipationless diamagnetic response is central to magnetic levitation and circuits such as quantum interference devices. In this work, we used superconducting diamagnetism to shape the magnetic environment governing the transport of spin waves-collective spin excitations in magnets that are promising on-chip signal carriers-in a thin-film magnet. Using diamond-based magnetic imaging, we observed hybridized spin-wave-Meissner-current transport modes with strongly altered, temperature-tunable wavelengths and then demonstrated local control of spin-wave refraction using a focused laser. Our results demonstrate the versatility of superconductor-manipulated spin-wave transport and have potential applications in spin-wave gratings, filters, crystals, and cavities.

Permanent Magnet Motors in Energy Storage Flywheels

Flywheel energy storage system stores energy in the form of mechanical energy and can convert mechanical energy into electrical energy. Flywheel energy storage is a mechanical energy storage system. Due to its high energy storage density, high power, high efficiency, long life, no pollution and other characteristics, it has a broad application prospect in the field of aerospace, power peaking, UPS, electric vehicles, high-power electromagnetic guns and so on. With the continuous development of magnetic levitation, composite materials, vacuum and other technologies, the current flywheel energy storage technology is mainly through the increase in the speed of the flywheel rotor to achieve energy storage, the continuous development of various technologies, so that the research of flywheel energy storage technology has stepped into the "high-speed" development period, and has been widely used in many fields. Application, and gradually become the focus of research in various countries.

Force and Torque Model of Magnetically Levitated System with 2D Halbach Array and Printed Circuit Board Coils

Precision machining fields often require worktables with different stroke sizes. To address the need for scalability and facilitate manufacturing, this study proposes a novel infinite expansion magnetically levitated planar motor (MLPM) based on PCB stator coils. Different from existing magnetic levitation systems that use PCB coils, the design presented in this paper utilizes smaller coil units, with each coil being independent of one another. The coils are structured in a spiral pattern on a 16-layer PCB, comprising 15 layers of coils, while the last layer is dedicated to wiring and other circuits. Magnetic field modeling is conducted for both the stator coil and the 2D Halbach array structure employed in the system. A simple table lookup method is employed to accurately account for the prevalent end effects observed during system motion. Additionally, the decoupling effect of magnetic force and torque is evaluated by solving for the current vector at different points along a specific trajectory. To verify the accuracy of the proposed system’s modeling, a prototype is developed and tested. Experimental results demonstrate that compared to traditional harmonic model methods, the proposed approach improves the calculation accuracy of magnetic force by 50.31% and torque by 70.65%. This study presents a new MLPM system with vast potential applications in precision manufacturing and robotics. The innovative design and improved performance characteristics make it a promising technology for enhancing the capabilities of worktables in precision machining fields.

Innovation and Research for Space Elevators

Progress continues on suitable materials for constructing the tether of a space elevator. Graphene super laminate is the most promising, and manufacturers are already producing significant quantities of graphene. Work is also continuing on a multi-stage space elevator, supported dynamically using magnetic levitation; the advantage is that it can be built with weaker materials, or even with materials that are already available today. The far end of a space elevator offers exciting opportunities to launch interplanetary spacecraft frequently with little or no fuel and with gentle rides at low cost. The node at geosynchronous altitude can accommodate unlimited mass and offers many commercial and scientific opportunities such as astronomy, communications and space-based solar power. Keywords: Little Fuel, Gentle Rides, Available Materials, Interplanetary

Asymmetric magnetic levitation for density-based measurement and analysis

BackgroundMagnetic levitation (MagLev) based on negative magnetophoresis represents a promising technology for density-based analysis and manipulation of nonmagnetic objects. This approach has garnered considerable interest across multiple fields, such as chemistry, materials science, and biochemistry, primarily due to its inherent simplicity, precision, and cost-effectiveness. However, it is essential to recognize that frequently used MagLev configurations, including standard MagLev and axial MagLev, are not without their limitations. These configurations often struggle to strike a balance between levitation performance, ease of operation, and visibility. Therefore, it is necessary to develop a new MagLev configuration to address the aforementioned issue. ResultsThis work describes the development of an innovative MagLev, termed “asymmetric MagLev”, achieved by combining a ring magnet and a cylinder magnet as up-down asymmetric magnetic field sources. The asymmetric design overcomes the physical obstacles along the centerline of the standard MagLev, offering unique open-structure advantages, including easy handling of samples, the ability to observe samples from the top or bottom, and no restrictions on the container height. Meanwhile, comparative analysis reveals a considerable enhancement in the working distance of the asymmetric MagLev without significantly sacrificing the measurement range compared to the axial MagLev. Notably, the asymmetric MagLev achieves a remarkable sensitivity of up to about 1.8 × 104 mm (g cm−3)−1, surpassing the axial MagLev by approximately 30 times. Furthermore, experimental results validate the successful application of the asymmetric MagLev in density measurement and quality detection of small-sized objects. SignificanceThis pioneering configuration represents the first utilization of up-down asymmetric magnets in the field of MagLev. Through the integration of an axially magnetized ring magnet and a cylinder magnet, the asymmetric MagLev design overcomes the limitations associated with conventional MagLev configurations. This innovative design exhibits outstanding operational capabilities and levitation performance, making it suitable for a wide range of applications in density-based measurement and analysis.

Protection method of traction power supply system for low and medium speed Maglev traffic based on fault traveling wave features

AbstractLow and medium speed magnetic levitation traffic with short power supply distance and complex grounding network structure, prone to power supply rail grounding faults. However, the existing fault location methods do not accurately locate the fault point, making it difficult for the protective device to act to cut off the fault. To address the above problems, this paper builds a dynamic simulation model of the low and medium speed magnetic levitation power supply rails to study the distribution characteristics of the fault traveling waves after a ground fault occurs in the power supply rails, and analyses the generation mechanism of the traveling wave spectrum through formula calculation. First, the difference in current between the positive and negative bus bars is analyzed to determine whether a ground fault has occurred. Second, the direction of the current difference between stations is compared to locate the faulty section. Finally, the fault distance is calculated from the frequency difference of the fault voltage at the double‐ended station. Through simulation, the method is validated to be unaffected by fault location, fault transition resistance, noise interference, and is applicable to short circuit faults caused by lightning strikes, and the ranging error always remains within 20 m. The method has strong robustness, can effectively solve the problem of protection misoperation and accurately locate the fault point. It is suitable for low and medium speed magnetic levitation transportation power supply rail ground fault.