Levitation Research Articles

Levitation by thin viscous layers

Levitation by thin viscous layers

Tuned Parameters of PID for Optimization of Losses in Magnetic Levitation System

Tuned Parameters of PID for Optimization of Losses in Magnetic Levitation System

Investigation of standing wave acoustic levitation with Bernoulli principle and bolt-clamped Langevin type ultrasonic transducer

Investigation of standing wave acoustic levitation with Bernoulli principle and bolt-clamped Langevin type ultrasonic transducer

Levitating in a Fluid

Levitating in a Fluid

Employing coupled cavities to increase the cooling rate of a levitated nanosphere in the resolved sideband regime: publisher’s note

This publisher’s note amends the spelling of the second author’s name in J. Opt. Soc. Am. B35, 1563 (2018)JOBPDE0740-322410.1364/JOSAB.35.001563.

Enhanced IMC synthesis for tracking control of magnetic levitation system

This paper presents an enhanced internal model control (EIMC) scheme for a time-delayed second order unstable process, which is subjected to exogenous disturbance and model variations. Even though the conventional internal model control (IMC) can provide an asymptotic tracking response with desired stability margins, the major limitation of conventional IMC is that it cannot be applied for an unstable system because a small exogenous disturbance can trigger the control signal to grow unbounded. Hence, modifying the conventional IMC structure to guarantee the internal stability, we present an EIMC scheme which can offer better trade-off between setpoint tracking and disturbance rejection characteristics. To improve the load disturbance rejection characteristics and attenuate the effect of sensor noise, we solve the selection of controller gains as an H∞ optimization problem. One of the key aspects of the EIMC scheme is that the robustness of the closed loop system can be tuned via a single tuning parameter. The performance of the EIMC scheme is experimentally assessed on a magnetic levitation plant for reference tracking application. Experimental results substantiate that the EIMC scheme can effectively counteract the inherent time delay in the model and offer precise tracking, even in the presence of exogenous disturbance. Moreover, by comparing the trajectory tracking performance of EIMC with that of the proportional integral velocity (PIV) controller through cumulative power spectral density (CPSD) of the tracking error, we show that the EIMC can offer better low frequency servo response with minimal vibrations.

Forces and dynamics of optically levitated polystyrene particles in air using electrostatic modulation

Forces and dynamics of optically levitated polystyrene particles in air using electrostatic modulation

Sorting cells through levitation

Sorting cells through levitation

Lab Levitation, How Bubbly Is Bubbly?

Lab Levitation, How Bubbly Is Bubbly?

On the Desire to Levitate: Poems by Alison Powell (review)

On the Desire to Levitate: Poems by Alison Powell (review)

Investigation the Properties of Y-Ba-Cu-Oxide Superconductors Prepared by Hydraulic Pressing and Molding

Levitation applications of superconductors require the fabrication of bulk ceramic superconductors with special shapes. The conventional hydraulic pressing is not suitable for the production of superconductors with complicated forms, so we have applied slip casting to shape bulk superconductors. Superconducting powders with different YBa2Cu3Oy (123) and Y2BaCuO5 (211) phase content and different (Pt, Pb, Ce) additives were prepared by solid-state reactions. The nonsuperconducting (211) particles can be considered as flux pinning centres; thus the magnetic properties can be influenced by their amount and particle sizes. The addition of a few weight percent of dopant in the nominal composition can modify the particle size and distribution of the (211) grains. We have investigated and compared the phase compositions, morphologies and magnetic levitation forces of bulk superconductors formed by hydraulic pressing and moulding. The shielding abilities of a moulded superconductor were simulated with the COMSOL Multiphysics 4.4 software.

Model of overlapping effect of levitation lunar dust

Model of overlapping effect of levitation lunar dust

Maximizing the Magnetic Force Generated by an Actuator with Non-Magnetic Body in a Ferrofluid Pre-Magnetized by Permanent Magnets

The purpose of this paper is to investigate possibilities and means that lead to the increase of the magnetic force generated by an actuator with a non-magnetic body levitated in a ferrofluid pre-magnetized by permanent magnets. The numerical simulations outline the components of the structure, dimensions and magnetic constants of materials that render a maximum magnetic force. The experimental measurements effectuated on an experimental model of the actuator are in acceptable agreement with theoretical and simulation results

Glued intraocular lens scaffold

Purpose To explain the procedure and technicalities of Glued intraocular lens (IOL) scaffold. Setting Dr Agarwal’s Eye Hospital and Eye Research Centre, Chennai. Methods Following a posterior capsule rupture, the remnant nuclear fragments are manipulated and levitated into the anterior chamber. Glued IOL technique is performed initially followed by IOL scaffold technique. Result Glued IOL scaffold is very effective in compartmentalization of the anterior and posterior chamber and effectively allows nucleus emulsification. Conclusion Glued IOL scaffold prevents the chances of nucleus drop following posterior capsule rupture in eyes with insufficient iris and capsule support.

Posterior assisted levitation for subluxated lens extraction

Objective To evaluate the clinical effect of subluxated lens extraction with posterior assisted levitation. Methods The data in 7 cases (7 eyes) of subluxation of lens (over two quadrant) were analysed retrospectively. An assistant instrument had taped into vitreous cavity through pars plana for levation of the subhtxated lens. The lens was elevated into anterior chamber and was extracted. Preoperative and postoperative visual acuity, intraocular pressure and retinal complications were observed. Results Subluxated lens of all the 7 cases were extracted smoothly without posterior vitrectomy. Conclusions Posterior levitation assisted lens is effective and safe for subluxated lens of over two quadrant. Key words: subluxation of lens; operative method

Simultaneous Co-deposition of Zn-Mg Alloy Layers on Steel Strip by PVD Process

This is the first release of an interim report on the development of coating technology of Zn-Mg alloy layers on steel strip by EML-PVD (electromagnetic levitation - physical vapor deposition) process in an air-to-air type continuous PVD pilot plant. It intends to introduce a basic principle of the EML-PVD process together with the high speed PVD pilot plant built in Posco. Due to the agitation effect provided by the high frequency induction coil, simultaneous evaporation of Zn and Mg from a droplet could produce alloy coating layers with Mg content of 6% to 12% depending on the composition of the droplet inside the coil. For its superior corrosion resistance, Zn-Mg alloy coated steel would be a very promising material for automotive, electrical appliances, and construction applications.

Hierarchical motion synthesis of magnetically levitated trains

The technique of hierarchic construction of magnetic levitated train motion is offered. Its advantages and expediency of three-leveled system regulator were grounded. The global algorithm of its work is constructed.

Design and Characteristic Analysis of Hybrid-Type Levitation and Propulsion Device for High-Speed Maglev Vehicle

This paper deals with the design and characteristic analysis of electro-magnet/permanent-magnet (EM-PM) hybrid levitation and propulsion device for high-speed magnetically levitated (maglev) vehicle. The machine requires PMs with high coercive force in order to levitate the vehicle by only PMs, and propulsion force is supplied by long-stator linear synchronous motor (LSM). The advantages of this configuration are an increasing levitation airgap length and decreasing total weight of the vehicle, because of the zero-power levitation control. Several design considerations such as machine structure, manufacturing, and control strategy are described. Moreover, the levitation and propulsion device for high-speed maglev vehicle has been designed and analyzed usign the electromagnetic circuit and FE analysis. In order to verify the design scheme and feasibility of maglev application, 3-DOF static force test set is implemented and tested. The obtained experimental data using the static tester shows the validity of the design and analysis approaches.

Simulation and Experimental Analysis of Magnetic Levitation Relative Stability for the Flywheel Energy Storage

Abstract - In this paper , the relative stability of magnetic bearing system for the flywheel energy storage is evaluated using both simulation and experimental analysis. We make the simulation model for the magnetic bearing flywheel system using the rigid body shaft model. According to international standard ISO 14839-3, We experimentally analyzed the relative stability of magnetic bearing system . Additionally using both the simulation model and experimental tests , Phase margin and Gain margin is acquired through Nyquist plot.Key Words : Flywheel, Relative stability, Magnetic levitation† 교신저자, 정회원 : 한전 전력연구원 선임연구원E-mail : bcpark@kepri.re.kr*비 회 원 : 한전 전력연구원 선임연구원** 비 회 원 : 한전 전력연구원 책임연구원․공박***정 회 원 : 한전 전력연구원 연구원․공박§ 정 회 원 : 한전 전력연구원 책임연구원․공박§§ 비 회 원 : 한전 전력연구원 연구원 접수일자 : 2010년 6월 24일 최종완료 : 2010년 7월 28일 1. 서 론 플라이휠의 에너지 저장용량은 회전속도의 제곱에 비례하기 때문에 에너지 저장밀도를 향상시키기 위해서는 회전속도를 높이는 것이 필요하며, 이때 회전축을 지지해주는 베어링의 성능은 최대회전속도의 향상에 직접적인 관계를 가지고 있다. 비접촉식 자기부상베어링은 회전속도가 볼베어링에 비해 높으며, 수명이 길고 진공환경에서 적용하기에 적절한 장점을 가지고 있어 터보진공펌프, 공작기계, 터보압축기, 플라이휠 에너지 저장 장치 등에 상업화가 이루어졌거나 적용 연구가 진행되고 있다.[4][5][6][7]자기부상베어링은 feedback 제어가 없으면 기본적으로 불안정한 특성을 가지므로 제어기, 증폭기, 전자석 구동기, 위치센서로 구성되어 있는 것이 일반적이다. 이때 제어기는 자기베어링시스템의 불안정한 pole을 안정한 영역으로 이동시키는 역할을 한다. 본 논문에서 자기베어링에 사용한 제어기는 PD제어기로써, 적절한 P 게인, D 게인을 tunning 함으로써 자기베어링이 안정영역에서 동작하도록 제어기를 설계하였다. 본 논문에서 실험에 사용한 플라이휠 에너지 저장장치의 사진은 그림 1 의 5kWh급 플라이휠 에너지 저장장치 시스템이다. 이 시스템에서 실험하고 있는 회전축은 두 가지이며 첫 번째는 회전에너지를 주로 저장하는 부위가 회전축의 복합재 부위로써, 정격속도(18,000rpm)에서 사용가능한 저장 에너지가 5kWh인 회전축 이며, 두 번째는 고속회전 및 전동/발전기 검증용으로 사용하는 스틸로터형(steel rotor) 회전축으로써 회전에너지를 주로 저장하는 부위가 STS304로 제작된 형태이며, 본 논문에서는 스틸로터형 회전축에 대해 시뮬레이션 및 실험을 하였다. 그림 1 5kWh급 플라이휠 에너지 저장장치Fig. 1 5kWh flywheel energy storage그림 2는 본 논문에서 사용한 플라이휠 에너지저장장치의 주요구성품들의 개략도를 보여준다. 본 플라이휠 에너지저장장치는 스틸로터 휠, 전동/발전기, 자기베어링, 회전축으로 구성되어 있다. 회전축은 비자성체이며 가공성이 양호한 STS304를 사용하였다. 전동/발전기는 slotless형 동기 영구자석 전동/발전기로써 정격출력 10kW, 정격속도 22,000rpm, 최대토크는 4.53 Nm의 성능을 가진다. 본 전동/발전기는 회전손실을 최소화 하기위해 slotless형으로 설계/제작 하였다.

Physicists have 'solved' mystery of levitation

Physicists have 'solved' mystery of levitation