ENEIDE: An experiment of a spaceborne, L1/L2 integrated GPS/WAAS/EGNOS receiver

The ENEIDE mission consisted of 22 scientific experiments that were carried out on the Soyuz and on the International Space Station (ISS) during the flight of the Soyuz 10S to the ISS in April 2005. Among these experiments there was the ENEIDE instrument, which gave the name to the whole mission. ENEIDE is a space-qualified, dual-frequency, integrated GPS/WAASEGNOS receiver aimed to the verification of the tracking of GPS plus the augmentation systems from space. The receiver is built by Thales Alenia Space-Italia, Milan plant (formerly Laben), on the basis of the space-qualified dual-frequency receiver LAGRANGE, that will be a payload of several ESA and Italian Space Agency missions like ESA’s GOCE or the Italian COSMO SKYMED constellation to cite few examples. This paper addresses the first results of the ENEIDE flight data analysis.     

Transient Eddy Current NDE System Based on Fluxgate Sensor for the Detection of Defects in Multilayered Conducting Material

This paper describes a novel transient eddy current non destructive evaluation (NDE) system for the detection of defects in a multilayered conducting material by using fluxgate magnetometer as a sensor. In conventional eddy current NDE, the depth of defect detection is restricted due to the excitation frequency and its associated skin depth. Similarly, in conventional pulsed eddy current testing the time derivative of the secondary magnetic field, which decays much faster than the magnetic field itself, is measured by the induction coil. However, in this work we use fluxgate magnetometer which measures magnetic field directly and double “D” differential excitation coil in order to enhance the depth of investigation. In addition to this, the other instruments such as transmitter, transmitter controller and data acquisition system used for this work are the same one used for TEM based geophysical applications. The system has been used for the detection of an artificially engineered defect in an aluminum plate at a depth of 2 mm as well as 20 mm below the surface.     

Tilted toroidal coils for superconducting magnetic energy storage systems

Superconducting magnetic energy storage (SMES) systems can be used to improve power supply quality and reliability. In addition, large amounts of power can be drawn from a small stored energy supply. Nevertheless, the strong electromagnetic force caused by high magnetic fields and coil current is a serious problem for SMES. To cope with this problem, we propose a new coil design, the tilted toroidal coil (TTC). The TTC, obtained from the toroidal field coil (TFC) system by varying two pitching angles, allows the balancing of the electromagnetic force in the major radius direction, maintaining the same manufacturing simplicity of the TFC system. After determining balanced configurations through computer simulation, we built an experimental device to confirm the feasibility of the balancing effect.     

Two Dimension Finite Element Simulations on the Electromagnetic Containment in Twin-Roll Strip Casting

Distribution of magnetic field and electromagnetic force in twin-roll casting of steels was studied by the metod of numerical simulation in this paper,Two-dimension finite element model ,which includes the regions of melt ,stainless collar ,coil and magnetic core ,has been constructed,By solving magnetic vector potential formulations of quasi-static electromagnetic field,distribution of magnetic flux density and magnetic force at different molten heigh is determined,Calculated results showed that intensity of the distribution of magnetic flux density increased linearly with the increased coil current ;and the magnetic force in the melt increased as a quadratic cure with creased coil current ,More attention was given to the distribution of eddy current and magnetic force in the melt ,the confine effect at different molten height was also discussed.     

Spectral estimation for a magnetostrictive magnetic field sensor

Recently there has been increasing concern regarding the effects of low-frequency magnetic fields on humans and livestock. A portable magnetometer is essential for monitoring the field dose encountered. There are some devices currently available for this purpose which use the induced EMF technique. The field sensitivity for these devices depends on the number of turns of coil used. This limits the minimum size of devices with reasonable performance. The magnetometer considered in this paper overcomes this size limitation by using a highly magnetostrictive material, Terfenol-D, as the magnetic field sensor. The primary focus of this paper is to determine the magnetic field spectral characteristics using digital signal processing. A survey of spectral estimation techniques are presented, followed by their application to the Terfenol-D magnetic field signal. The estimators are compared using data obtained from a magnetometer hardware prototype. Using these methods it was possible to detect signal for a field strength of 20 milligauss     

管坯电磁成形时线圈受力的研究

成形线圈设计是电磁成形工艺的关键技术之一,为了有针对性地进行防破设计,提高线圈的使用寿命,采用数值模拟的方法研究了螺线管线圈和阶梯形线圈电磁胀形时的磁场,得到了成形瞬间的磁力线分布和线圈受到的磁压力分布.结果表明:线圈、工件的结构参数和相对安装位置对线圈的磁压力分布影响很大;将受力分布引入成形线圈设计,有效地提高了工艺实验中线圈的使用寿命.     

Structure and phase transition of BiFeO3 particles prepared by hydrothermal method and the verification of crystallization–dissolution–crystallization mechanism

The optimal synthesis temperature of BiFeO₃ is found. The cube BiFeO₃ powders have a hexagonal perovskite structure with a space group R3c, while the sphere-like BiFeO₃ powders have a rhombohedral structure with a space group R3m. The growth mechanism of crystallization–dissolution–crystallization has been summarized and verified. The effect of the reaction time on the particle size in hydrothermal synthetic experiment is studied. The magnetic properties of samples prepared under different alkali concentration have been measured by vibrating sample magnetometer. It is indicated that the samples with different morphologies exhibit different magnetic properties. A reasonable explanation for this phenomenon has been given in this paper.     

Electromagnetic Analysis of the ITER Upper VS Coil

In order to control the plasma vertical stability of ITER, a novel magnet is developed, that is the vertical stability coil. The coil is located in the vacuum vessel and its safe operation is very important for ITER’s reliable working. During the normal operation, the coil should bear the electromagnetic force caused by the external superconducting magnet and plasma current. The electromagnetic load is one of the important factors to affect the lifetime of the VS coil. Therefore, it is necessary to calculate the magnetic field and evaluate the structural reliability under the electromagnetic load. In this paper, the current at the time “end of burn” was selected to perform the electromagnetic calculation. Based on the Maxwell equation, the magnetic field on the cross section of the upper VS coil was computed and the maximum electromagnetic force corresponding to the magnetic field was also presented. In order to verify the current design model, the finite element model was created by use of ANSYS. The Tresca stress was extracted and classified based on analytical design. The peak stress was compared with the ASME criteria. The analysis has verified the physical model from the perspective of electromagnetic load, and it will offer a guidance for the future optimization.     

Principle and Performance of a Dual-Band Search Coil Magnetometer: A New Instrument to Investigate Fluctuating Magnetic Fields in Space

Search-coil magnetometers are of common use in space physics thanks to their simplicity, robustness and ability to measure weak magnetic fields: their sensitivity can reach a few tens of fT/?Hz in the range 10-100 kHz. The frequency band is grossly determined by the resonance of the coil. Simply adding a second coil does not efficiently extend the frequency band beyond the first resonance due to the mutual impedance of the two coils. We present a solution, called ?mutual reducer,? which allows us to take full benefit of the second coil and efficiently extends the frequency band. The physical principle is described first, followed by a detailed presentation of this ?dual-band search-coil? (DBSC) that will be part of the plasma wave instrument (PWI) onboard the Mercury magnetospheric orbiter (MMO) of the ESA-JAXA mission BepiColombo dedicated to the exploration of the plasma environment of planet Mercury.     

20G钢管的电磁校形

采用线圈轴向磁场力对压扁量为11mm的20G钢管进行了电磁校形,并以变形量为评价指标,研究了放电电压、放电次数和线圈电感对钢管校形精度的影响。结果表明：虽然线圈电感和放电次数对校形精度有一定的影响,但放电电压是影响校形精度的决定因素;试验还从各种参数对校形的影响关系得到了较优化的工艺参数,以达到提高校形效果的目的。     

Field trial of an electrically passive optical-fiber magnetometer

A field trial of an electrically passive optical-fiber magnetometer incorporated into the transient electromagnetic method of geomagnetic surveying is described. The transducer of the magnetometer consisted of metallic glass wire cocoated with a length of optical fiber. The magnetometer was capable of measuring the decay rate of the surface magnetic field produced by the surveying technique. The sensor's minimum detectable field was 2.5 × 10(-8) G/√Hz at 2 kHz.     

Biological dosimetry in the ENEIDE Mission on the International Space Station

Space radiation represents one of the major health hazards to crews of interplanetary missions. As the duration of space flight increases, according to International Space Station (ISS) and Mars mission programs, the risk associated with exposure to ionizing radiation also increases. Although physical dosimetry is routinely performed in manned space missions, it is generally accepted that direct measurement of biological endpoints (biological dosimetry) is necessary for a precise assessment of radiation risk in extraterrestrial activities. Chromosomal aberrations (CAs) in peripheral blood lymphocytes (PBLs) are particularly suitable to this purpose, as they can provide estimates of both equivalent radiation dose and risk. In this study, cytogenetic analysis was performed on PBL chromosomes of an Italian astronaut involved in two different 10-day missions on the ISS (Marco Polo, April 2002, and ENEIDE, May 2005). Blood samples were collected before and after flights. CAs were evaluated in either mitotic spreads or in prematurely condensed chromosomes (PCC) by Fluorescence in Situ Hybridization (FISH). In addition, blood samples were exposed to graded doses of X-rays in vitro before and after the flight and cytogenetic damage evaluated to investigate whether the space environment alters the sensitivity of human cells to ionizing radiation. The yield of baseline chromosomal aberrations was not modified following Marco Polo and ENEIDE mission. This is consistent with the low dose absorbed in these short-term space missions. Preliminary results from Marco Polo mission suggested a significant increase in intrinsic radiosensitivity of lymphocytes after landing compared to pre-flight and follow-up (6 months after landing) samples. However, this effect was not observed during the ENEIDE mission. The results suggest that intra-indi-vidual variations in radiosensitivity are significant, but they cannot be related to the space flight.     

Upgrade of the Alpha Magnetic Spectrometer (AMS-02) for long term operation on the International Space Station (ISS)

Following the decision to maintain the International Space Station (ISS) on orbit until at least 2020 (possibly until 2028) the AMS collaboration decided to correspondingly extend the lifetime of the experiment. Since the limited amount of helium used to cool the superconducting magnet allowed for only a limited run time of the experiment, a change from the superconducting magnet to the permanent magnet used in AMS-01 became necessary. Due to the lower magnetic field, to maintain the resolution the silicon tracker also had to be reconfigured with the installation of a silicon plane on the top of the experiment and a new plane above the electromagnetic calorimeter.     

Low magnetic field measurement with a reversed-fieldelectron-spin-resonance magnetometer

An effective method of measuring low magnetic fields is presented. In this method, the magnetic field direction is reversed periodically so that the effects of external magnetic fields, such as the earth's magnetism, are removed. The usefulness of the method is investigated by using a split coil magnetic field source and an electron-spin-resonance magnetometer. A magnetic field of 10 mT can be measured with an uncertainty of less than 0.2 μT, i.e., 20 ppm     

磁铁矿铁磁性能解析及应用

探讨磁铁矿物理化学特性,研究单线圈阻抗检测方法,用其实现铁矿选矿工艺过程中全铁品位指标的在线自动监测.采用X射线衍射分析方法和电感耦合等离子体质谱方法表征磁铁矿原矿及铁精粉矿样的物相组成及化学成分.利用振动样品磁强计测试矿样的磁化强度、矫顽力、比磁化系数等磁学性能指标,解析磁铁矿的强磁性能,应用其铁磁特性探讨交流激磁、矩型电感线圈、磁铁矿铁芯等条件下全铁品位指标的电磁感应测量方法及测试机理.设计信息采集装置、信号调理电路以及PIC单片机控制系统,给出温湿度测试方法及温度补偿方案.实验测试结果表明:应用磁铁矿铁磁特性进行全铁品位指标电磁效应在线监测具备可行性,铁精粉干粉实验测试误差低于±0.5%,测量标准差为0.19%.     

Numerical simulations of an electromagnetic acoustictransducer-receiver system for NDT applications

The development of a multistage numerical model of an electromagnetic acoustic transducer (EMAT), with particular emphasis on an EMAT receiver, is presented. The model includes five separate modeling states: static magnetic field simulation of an electromagnet; pulsed eddy current distribution of a generic meander-line coil suspended over a conducting specimen; Lorentz force distribution due to the interaction of the static magnetic field with the eddy current distributions; acoustic wave generation and propagation based on the dynamic Lorentz forces; and acoustic wave detection by an EMAT receiver. In particular, it is shown how the transient particle displacement fields are converted into an induced voltage response as part of the EMAT receiver system. Numerical simulations show that the voltage response is dependent on the wire spacing of the receiver coil     

一种高准确度的标准磁场装置

采用宽频比较仪的电流检测技术,设计了高稳定度和高准确度的电流源,与亥姆霍兹线圈组成了高准确度标准磁场装置,从而实现对磁强计的校准。标准磁场经标定后,上位机软件能自动显示磁通密度,作为标准磁场使用。     

Features of electromagnetic thermal protection of space capsule

The problem of using a magnetic field to reduce heat fluxes on the surface of a flying vehicle is discussed as a continuation of the previous investigations [1–3]. A classical electromagnetic thermal protection scheme that uses a magnetic dipole oriented opposite to the oncoming flow is considered for a space capsule of Stardust (NASA space probe) mission entering the Earth’s atmosphere. It is shown that, for fairly high magnetic fields, the distribution of heat flux on the capsule surface weakly depends on the field amplitude, while the shock-wave stand-off distance from the surface increases in proportional to the field amplitude.     

A magnetometer for the pioneer venus orbiter

A magnetic field experiment was designed to be placed in orbit around the planet Venus by the Pioneer Venus Orbiter spacecraft. The experiment system employs three fluxgate magnetometer circuits and a novel digital data processing section that extracts useful magnetic field data for both high and low data transmission rates.     

Analysis of a novel laminated coil using eddy currents for AC highmagnetic field

The analysis and performance of an eddy current type laminated coil for a high AC magnetic fields are described. It is usually difficult to obtain a high AC magnetic field using an air-gap coil because of eddy currents. The present coil circumvents this limitation by making use of the magnetic shielding effect of eddy currents. Two different realizations of the coil are proposed to provide design flexibility. The field distributions are analyzed by the two-dimensional finite-element method. The coils can also be applied to an induction electromagnetic pump