Electrodynamic separators based on linear inductors with diverging magnetic fields

The electromagnetic processes in linear induction machines with a short secondary component and a primary coil creating diverging magnetic fields are considered. Recommendations are made regarding the types of windings for such machines. It is expedient to use such machines in electrodynamic separators with bilateral product discharge.     

A new approach for motion capture using magnetic field : models,algorithms and first results

Indoor and outdoor applications such as sports and health monitoring as well as realistic 3D movie and game animations require ambulatory motion capture. Thus, creating a new low‐cost light‐weight wearable motion capture system that offers realistic motion estimates is of great interest. This paper presents a new approach for ambulatory human motion capture, featuring a body mounted magnetic field source and magnetic field sensors together with an estimation algorithm. A complete study of the model, the hardware, and the estimation algorithms is presented. Results obtained in the context of motion capture of human upper limbs illustrate the proposed approach.Copyright © 2014 John Wiley & Sons, Ltd.     

磁导仪极靴形状对软磁材料性能测量结果的影响

自动控制仪器与软磁材料性能之间存在着密切的关系,这就使得软磁测量的重要性日渐突出,特别是在智能化日益发展的今天。对于不被认为是传统意义上的软磁材料的铁素体不锈钢材料,情况尤其如此。实验表明,为减小测量误差,应尽量选择与样品接触面尽可能大的极靴。因为无论是在弱场、中场还是强场下,极靴形状对样品测量结果的影响都是不可忽视的,特别是当极靴形状与样品的接触面很小的情况下。对于?max所在的磁场值H(?max),即使使用同一幅极靴进行测量,在不同的磁场下,测量值间也存在较大的差异。但极靴形状对材料最大磁通密度,也就是最大磁极化强度的影响不大。这些结果对磁路设计也很有借鉴意义。     

P792: a rapid clearance blood pool agent for magnetic resonance imaging: preliminary results

An original MRI contrast agent, called P792, is described. P792 is a gadolinium macrocyclic compound based on a Gd-DOTA structure substituted by hydrophilic arms. The chemical structure of P792 has been optimized in order to provide (1) a high r₁ relaxivity in the clinical field for MRI: 29 mM⁻¹ x s⁻¹ at 60 MHz. (2) a high biocompatibility profile and (3) a high molecular volume: the apparent hydrodynamic volume of P792 is 125 times greater than that of Gd-DOTA. As a result of this high molecular volume, P792 presents an unusual pharmacokinetic profile, as it is a Rapid Clearance Blood Pool Agent (RCBPA) characterized by limited diffusion across the normal endothelium. The original pharmacokinetic properties of this RCBPA are expected to be well suited to MR coronary angiography, angiography, perfusion imaging (stress and rest), and permeability imaging (detection of ischemia and tumor grading). Further experimental imaging studies are ongoing to define the clinical value of this compound.     

A vibrational model using modal shapes and magnetic forces: experimental results for a permanent magnet machine

Contents The frequency inverter current spectrum generates a complex magnetic field in the airgap producing attracting forces having a wide spectrum and leads to audible noise. A mathematical model is presented, predicting vibrations of a permanent magnet machine, based on the modal analysis technique including mechanical damping. Modal forces produced by the magnetic field, are related to the supply currents using a finite element calculation. Experimental results are presented.

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Ein Schwingungsmodell mit Hilfe der Modalen Analyse und der magnetischen Kräfte: experimentelle Ergebnisse für eine Permanentmagnetmaschine

Übersicht Das Stromspektrum eines Frequenzumrichters generiert ein komplexes magnetisches Feld im Luftspalt, welches Anziehungskräfte mit einem breiten Frequenzgang hervorruft, die wiederum zu Geräuschen führen. Ein mathematisches Modell wird vorgestellt, welches es ermöglicht, die Schwingungen einer permanent erregten Maschine vorauszusagen. Es basiert auf der Modalen Analyse und enthält die mechanische Dämpfung. Vom Magnetfeld hervorgerufene modale Kräfte werden mit den eingespeisten Strömen mittels der Finite-Elemente-Methode in Verbindung gebracht. Experimentelle Ergebnisse werden dargestellt.

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The authors wish to thank the Council of the Belgian National Science Foundation for granting a project sponsoring the research.This paper presents results of the Belgian programme on Interuniversity Poles of Attraction initiated by the Belgian State, Prime Minister's Office, Science Policy Programming. The scientific responsibility is assumed by the authors.     

Identifying electrical safety needs, implementing improvement, andmeasuring results

The management of an operating and maintenance contractor for a large government-owned facility recognized that, despite having an overall good safety program, the number of electrical safety incidents at the facility was on the increase. The severity of these incidents had also been increasing, as indicated by a serious shock and burn injury to a young, but trained and qualified, employee. Management decided that a serious effort was needed to significantly reduce (and, ideally, eliminate) electrical safety-related incidents. This paper describes comprehensive management/employee involvement in identifying the real problem areas, implementing improvement, and continually measuring performance. Although this effort was undertaken at a large facility with many people involved, the paper provides ideas that can be considered on both a large and small scale for those companies where similar electrical safety concerns exist     

Superconducting magnetic resonance imaging: Supply,diagnostics, and protection

The parameters of prototypes of topological generators with resistive superconducting switches made of low-temperature superconductors (LTSCs) and high-temperature superconductors (HTSCs) are presented. The experimental results are presented. A technical evaluation of the use of topological generators for the precise supply of LTSC and HTSC windings of magnetic resonance imaging is given.     

Mining machine orientation control based on inertial,gravitational, and magnetic sensors

A computer-assisted mining machine requires subsystems for machine intelligence, navigation positioning, and computer control. One subsystem, an onboard, multisensor, computer-based heading system that would be responsible for determining and controlling machine heading is described. A directional gyroscope provides heading (yaw), fluxgate sensors provide compass data, and gravity-referenced clinometers give machine pitch and roll information. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, which are supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. The operating limitations and error sources of the system are presented, along with implementation of closed-loop control of machine yaw. Results from mine machine tests are used to exhibit the various sensor shortcomings and evaluate heading control during tests of machine pivots and turns     

The 3D nanometer device project nextnano: Concepts, methods, results

nextnano is a simulation tool that aims at providing global insight into the basic physical properties of realistic three-dimensional mesoscopic semiconductor structures. It focuses on quantum mechanical properties such as the global electronic structure, optical properties, and the effects of electric and magnetic fields for virtually any geometry and combination of semiconducting materials. For the calculation of carrier dynamics, two models are currently implemented that provide results for the limiting cases of highly diffusive or purely ballistic quantum-mechanical transport. In this paper, we present an overview of nextnano's present and future capabilities and discuss some key concepts in the areas of code structure, numerical techniques, and electronic structure principles.     

Fe:SmCo(Cr)薄膜的结构、磁性能与磁光克尔效应

利用脉冲激光沉积工艺,分别在单晶Si(100)衬底和玻璃(Si O2)衬底上制备Fe:Sm Co/Cu(Cr)薄膜,研究了Fe掺杂对Sm Co薄膜结构、磁性能与磁光效应的影响。实验发现,衬底对Fe掺杂Sm Co薄膜性能有很大影响,Si衬底薄膜的矫顽力和饱和磁化强度均优于玻璃衬底样品;同时退火温度也会影响Fe掺杂Sm Co薄膜形貌及磁性能,高温退火后,Sm Co衍射峰得到了增强,尤其是Sm Co5的(001)、(002)和(003)衍射峰最为明显,这是由于高温退火后Cu(111)衍射峰增强的缘故。同时发现,退火后的Si O2衬底与Si衬底样品的磁性和磁光效应均得到增强,但Si O2衬底的矫顽力Hc变化更明显,这是因为较高的表面应力会导致样品的矫顽力增强。因此可以通过调节Fe含量来控制样品的磁光性能,这就为优化Sm Co薄膜作为磁光存储介质的性能指出了一个研究方向。     

Recent results in color compositing of three-parameter magnetic resonance scans as a preoperative aid to the management of upper limb sarcomas

We report on improved image quality and some recent clinical results with volume-rendered, color composite, multiparameter, magnetic resonance (MR) datasets and their color histograms. In a previous article we demonstrated the major components of an interative visualization environment for multiparameterT ₁-,T ₂-, PD-weighted MR volume datasets. These are compositing of the three parametric volumes, color volume rendering of the resulting composite, interactive segmentation of the tissues based on color cluster statistics derived from display of the three-dimensional (3D) histogram, and head-tracking stereo diplay. We herein review the system design and describe improvements to the quality of the color volume rendering, in the display of the 3D color histogram data, and in the specification of the volume enderer’s opacity function. Finally, we report on some recent clinical results using our system.     

Voltage regulation with STATCOMs: modeling, control and results

This paper presents system modeling and control design for fast load voltage regulation using static compensators (STATCOMs). The modeling strategy gives a clear representation of load voltage magnitude and STATCOM reactive current on an instantaneous basis. The particular coordinate transformation employed here also facilitates extraction of linearized system dynamics in conjunction with circuit simulators. It is rigorously shown that the control problem of load voltage regulation using reactive current is nonminimum phase. Linear and nonlinear controllers for the regulation problem are designed and compared via simulation results. Internal dynamics of the STATCOM are modeled using the same strategy. Lyapunov based adaptive controllers are designed for controlling the STATCOM reactive current while maintaining its dc bus voltage. Simulation results of the controlled STATCOM integrated with the load bus voltage controller are presented to show efficacy of the modeling and control design.     

Issues,progress and new results in robust adaptive control

We overview recent progress in the field of robust adaptive control with special emphasis on methodologies that use multiple‐model architectures. We argue that the selection of the number of models, estimators and compensators in such architectures must be based on a precise definition of the robust performance requirements. We illustrate some of the concepts and outstanding issues by presenting a new methodology that blends robust non‐adaptive mixed µ‐synthesis designs and stochastic hypothesis‐testing concepts leading to the so‐called robust multiple model adaptive control (RMMAC) architecture. A numerical example is used to illustrate the RMMAC design methodology, as well as its strengths and potential shortcomings. The later motivated us to develop a variant architecture, denoted as RMMAC/XI, that can be effectively used in highly uncertain exogenous plant disturbance environments. Copyright © 2006 John Wiley & Sons, Ltd.     

Systematic study of elastic,electronic, and magnetic properties of lanthanum cobaltite oxide

The electronic structure, elastic constants, and magnetic properties of lanthanum cobaltite oxide \(\hbox {La}_{4}\hbox {Co}_{3}\hbox {O}_{9}\) compound, which crystallizes in orthorhombic space group Pnma, are investigated theoretically for the first time using the full potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory plus Hubbard correction term (DFT \(+\) U). The calculated equilibrium lattice constants and fractional atomic coordinates are in a good agreement with available experimental data. Our result for the formation energy and elastic constants confirms that the predicted \(\hbox {La}_{4}\hbox {Co}_{3}\hbox {O}_{9}\) is mechanically stable. This compound is found to be ductile in nature in accordance with Pugh’s criteria. The anisotropy factors (\({A}_{1})\), (\({A}_{2})\), and (\({A}_{3})\) of \(\hbox {La}_{4}\hbox {Co}_{3}\hbox {O}_{9}\) material are also predicted through the elastic constants. The electronic band structures show metallic behavior; the conductivity is mostly governed by Co-3d and O-2p states. The total magnetic moments of the tetrahedral (\(\hbox {CoO}_{4})\) and octahedral (\(\hbox {CoO}_{6})\) environments are, respectively, 2.502 \(\mu _{B}\) and 2.874 \(\mu _{B}\), which are consistent with the experimental measurements.     

Theoretical investigation of electronic performance,half-metallicity,and magnetic properties of Cr-substituted BaTe

We have investigated the structural, electronic, and ferromagnetic properties of chromium (Cr)-doped rocksalt BaTe (\(\hbox {Ba}_{1-x}\hbox {Cr}_{x}\hbox {Te}\)) compounds with compositions \(x = 0.25\), 0.5, and 0.75, based on density functional theory with generalized gradient approximation of Wu–Cohen (GGA-WC) and Tran–Blaha-modified Becke–Johnson (TB-mBJ) potential using the WIEN2k package. We found that the electronic structure showed half-metallic ferromagnetic character with spin polarization of 100 % around the Fermi level. In addition, the minority-spin bands depicted a half-metallic ferromagnetic (HMF) gap and half-metallic (HM) gap. The improved HMF and HM gaps found with the TB-mBJ potential are higher than with the GGA-WC approximation. These large HM gaps make \(\hbox {Ba}_{1-x} \hbox {Cr}_{x}\hbox {Te}\) compounds promising candidates for use in spintronics applications.     

Regularities of heat transfer in the gas layers of a steam boiler furnace flame. Part II. Gas layer radiation laws and the procedure for calculating heat transfer in furnaces,fire boxes,and combustion chambers developed on the basis of these laws

The article presents the results stemming from the scientific discovery of laws relating to radiation from the gas layers generated during flame combustion of fuel and when electric arc burns in electric-arc steel-melting furnaces. The procedure for calculating heat transfer in electric-arc and torch furnaces, fire-boxes, and combustion chambers elaborated on the basis of this discovery is described.