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Search results for: slow magnetic relaxations
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FAILURE OF MAGNETIC FLUID SEALS OPERATING IN WATER: PRELIMINARY CONCLUSIONS
PublicationThe article analyses properties of magnetic fluid seals installed in rotary sealing no des which operate in the utility water environment. Seals of this type have been examined as a possible solution to the problem with ship manoeuvring propulsion sealing. The present analysis bases on laboratory durability tests of magnetic fluid seals expo sed to long - term utility water loads, at different water pressures and shaft revolutions....
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Reduction of the Velocity Impact on the Magnetic Flux Leakage Signal
PublicationThe velocity effect on the magnetic flux leakage (MFL) signal was investigated in this paper. Experiments were performed for velocity of the MFL tool within the range of 0–2 m/s. The velocity was not constant during each measurement to imitate real operational conditions of the MFL tool. Two components of the leakage were measured, i.e. the tangential to the motion direction (x) and the normal to the investigated surface (z). In...
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TiO2-based magnetic nanocomposites with core-shell structure
PublicationThe main aim of the doctoral dissertation was preparation and characterization of photocatalysts, with particular emphasis on modified titanium (IV) oxide photocatalysts, which can be applied for the degradation of organic pollutants not susceptible to biodegradation. A particularly important aspect of the work was the development of preparation method of nanocomposites with the magnetic core-shell and photocatalyst shell (TiO2)...
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Relativistic two-dimensional hydrogen-like atom in a weak magnetic field
PublicationA two-dimensional (2D) hydrogen-like atom with a relativistic Dirac electron, placed in a weak, static, uniform magnetic field perpendicular to the atomic plane, is considered. Closed forms of the first- and second-order Zeeman corrections to energy levels are calculated analytically, within the framework of the Rayleigh–Schrödinger perturbation theory, for an arbitrary electronic bound state. The second-order calculations are...
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Magnetic Field Generated by Short Circuit Current in the 110 kV Power System
PublicationElectric fields within tissues induced by magnetic fields including transients or short-term peaks should not be time averaged and be regarded as instantaneous values as established in the ICNIRP (International Commission on Non - Ionizing Radiation Protection) guidelines. Measurements of power lines magnetic fields with regard to human beings exposure are carried out typically with maximum current load at current balance condition...
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Efficient long-term conservation of Taraxacum pieninicum synthetic seeds in slow growth conditions
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Stripe order and magnetic anisotropy in the S=1 antiferromagnet BaMoP2O8
PublicationMagnetic behavior of yavapaiite-type BaMoP2O8 with the spatially anisotropic triangular arrangement of the S=1Mo4+ ions is explored using thermodynamic measurements, neutron diffraction, and density-functional band-structure calculations. A broad maximum in the magnetic susceptibility around 46 K is followed by the stripe antiferromagnetic order with the propagation vector k=(12,12,12) formed below TN≃21 K. This stripe phase is...
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Effect of rotating magnetic field on ferromagnetic structures used in hyperthermia
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Magnetic penetration depth and correlation length in the superconductor with local pairing
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NEW DESIGNS OF CENTRIFUGAL MAGNETIC FLUID SEALS FOR ROTATING SHAFTS IN MARINE TECHNOLOGY
PublicationThe centrifugal magnetic fluid seals have important advantage over the conventional centrifugal seals. They maintain very good sealing capacity at static, medium and high speeds of shaft rotation, with the increased seal lifetime, and minimum torque and static friction. These seals are particularly useful in cases when the angular shaft velocity varies and sometimes decreases to nearly or exactly zero, such as in flywheel applications,...
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Dynamics of Field Line Mappings in Magnetic Flux Tubes
PublicationWe study the topological constraints on the dynamics of magnetic field lines in flux tubes. Our approach is based on the application of the topological invariant: fixed point index. We consider periodic flux tubes and find various restrictions on the field lines that come from the sequence of fixed point indices of iterations. We also analyze the case of a tube with a cylindrical obstacle, deducing some special dynamical properties...
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The study on possibilities of recovery non-magnetic fraction by utilisation the magnetic separation technology in conditions of KGHM Polska Miedz S.A. division of concentrators = Próby odzysku frakcji niemagnetycznej metodą separacji magnetycznej w warunkach KGHM Polska Miedź S.A. Oddział Zakłady Wzbogacania Rud
PublicationW referacie przybliżono wyniki badań prowadzonych w kierunku określenia możliwości odzysku frakcji niemagnetycznej i słabomagnetycznej ze strumieni materiałowych O/ZWR, poprzez wykorzystanie metody separacji magnetycznej. Przeprowadzony cykl badawczy obejmował analizę występowania frakcji magnetycznej i związanej z nią frakcji niemagnetycznej w obiegach technologicznych w Rejonie ZWR Lubin, oraz możliwości ich odzysku. Uzyskane...
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Site-selective magnetic order of neptunium inNp2Ni17
PublicationWe present the results obtained by superconducting quantum interference device (SQUID) magnetometry, specific heat, and Mossbauer spectroscopy measurements carried out on Np2Ni17 polycrystalline samples. We show that long-range magnetic order, with a moment mu((2b)) similar to 2.25 mu(B), occurs below T-N = 17.5 K on the Np (2b) sites. A nontrivial situation is observed in that the other Np sites (2d) do not take part to the order...
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Determination of Mechanical Properties of P91 Steel by Means of Magnetic Barkhausen Emission
PublicationIn this work, an attempt at determination of mechanical properties by means of a method based on magnetic Barkhausen emission measurements was proposed. The specimens made of P91 steel were subjected to creep or plastic flow which were interrupted after a range of selected time periods in order to achieve specimens with an increasing level of strain. Subsequently, measurements of magnetic Barkhausen emission were carried out, and...
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Nanodiamonds Doped with Manganese for Applications in Magnetic Resonance Imaging
PublicationNanodiamonds (NDs) are emerging with great potential in biomedical applications like biomarking through fluorescence and magnetic resonance imaging (MRI), targeted drug delivery, and cancer therapy. The magnetic and optical properties of NDs could be tuned by selective doping. Therefore, we report multifunctional manganese-incorporated NDs (Mn-NDs) fabricated by Mn ion implantation. The fluorescent properties of Mn-NDs were tuned...
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Growth, Crystal Structure and Magnetic Characterization of Zn-Stabilized CePtIn4
PublicationThe growth and characterization of CePtIn4, stabilized by 10% Zn substitution for In, is reported. The new material is orthorhombic, space group Cmcm (No. 63), with lattice parameters a = 4.51751(4) Å, b = 16.7570(2) Å, and c = 7.36682(8) Å, and the refined crystal composition has 10% of Zn substituted for In, i.e., the crystals are CePt(In0.9Zn0.1)4. Crystals were grown using a self-flux method: only growths containing Zn yielded...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results. Part II Results of life tests of multi-stage magnetic - fluid seal operating in water
PublicationThe edge criteria for magnetic-fluid seals durability research were described in previous article [24] and now the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are:...
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Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface
PublicationCore-interlayer-shell Fe3O4/SiO2/TiO2, CoFe2O4/SiO2/TiO2 and BaFe12O19/SiO2/TiO2 magnetic photocatalysts were obtained. A water-in-oil microemulsion system with suitable surfactants was used for functionalization of the magnetic core with silica interlayer and TiO2-based photocatalyst. Uncoated and coated particles were characterized by electrophoretic meaurements, X-ray diffractometry (XRD), scanning electron microscopy (SEM),...
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Discussion of Derivability of Local Residual Stress Level from Magnetic Stray Field Measurement
PublicationThe NDT procedure dubbed ‘metal magnetic memory’ method and the related ISO 24497 standard has found wide industrial acceptance in some countries, mainly in Russia and China. The method has been claimed by some researchers (Roskosz and Bieniek in NDT&E Int 45:55–62, 2012; Wilson et al. in Sens Actuators A 135:381–387, 2007) as having potential for quantitative determination of local residual stress state in engineering structures,...
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Electric and magnetic properties of Lanthanum Barium Cobaltite
PublicationThe cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3)...
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Multi-functional sensor based on photonic crystal fiber using plasmonic material and magnetic fluid
PublicationA unique highly sensitive photonic crystal fiber is investigated based on plasmonic material and magnetic fluid (MF) for the simultaneous measurement of temperature and magnetic field sensor. The designed sensor is explored by tracing the different parameters such as birefringence, coupling length, power spectrum, and the peak wavelength of the transmission intensity. The magnetic field and temperature computation are attained...
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Perforated alumina templates as a tool for engineering of CoPd film magnetic properties
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On the correlation between magnetoacoustic emission and magnetostriction dependence on the applied magnetic field
PublicationThe correlation between magnetoacoustic emission signal envelopes and magnetostriction curves is investigated. Two sets of samples are being considered: tempered martensitic steel and plastically deformed ferritic steel. It is shown that even though some general relations may be observed, as was demonstrated in the literature, the correlation is not always present. One may not expect to change both quantities in the same way if...
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New trifunctional acrylic water-based paint with self-cleaning, biocidal and magnetic properties
PublicationIn the present study, we report the synthesis and application of ZnFe2O4/SiO2-TiO2 nanocomposites with nonstoichiometric content of Fe to Zn used for the first time for the preparation of new generation trifunctional paints with self-cleaning, biocidal and magnetic properties. Currently, there are no compositions on the market for obtaining protective coatings in the form of paint, which simultaneously exhibit biocidal, magnetic...
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Electronic conductivity in the SiO2-PbO-Fe2O3 glass containing magnetic nanostructures
PublicationThe linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show...
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Polaronic and Mott insulating phase of layered magnetic vanadium trihalide VCl3
PublicationTwo-dimensional (2D) van der Waals (vdW) magnetic 3d-transition metal trihalides are a new class of functional materials showing exotic physical properties useful for spintronic and memory storage applications. In this article, we report the synthesis and electromagnetic characterization of single-crystalline vanadium trichloride, VCl 3 , a novel 2D layered vdW Mott insulator, which has a rhombohedral structure (R3, No. 148) at...
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A Case Study on the Desired Selectivity in Solid‐State Mechano‐ and Slow‐Chemistry, Melt, and Solution Methodologies
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Immobilization on magnetic nanoparticles of therecombinant trehalose synthase from Deinococcusgeothermalis
PublicationtIn our study the gene encoding trehalose synthase from Deinococcus geothermalis was cloned and overexpressed inEscherichia coli Rosetta (DE3)pLysS. Wild-type trehalose synthase has been purified from host protein after cell dis-ruption and precipitation at 20% ammonium sulphate saturation. Recombinant trehalose synthase was immobilizedonto glutaraldehyde activated silanized magnetic ferrous-ferric oxide by using covalent binding...
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Static electric and magnetic multipole susceptibilities for Dirac one-electron atoms in the ground state
PublicationWe present tabulated data for several families of static electric and magnetic multipole susceptibilities for hydrogenic atoms with nuclear charge numbers from the range $1\leq Z\leq137$. Atomic nuclei are assumed to be point-like and spinless. The susceptibilities considered include the multipole electric polarizabilities $\alpha_{\mathrm{E}L\to\mathrm{E}L}$ and magnetizabilities (magnetic susceptibilities) $\chi_{\mathrm{M}L\to\mathrm{M}L}$...
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Measurement Campaign and Mathematical Model Construction for the Ship Zodiak Magnetic Signature Reproduction
PublicationThe paper presents the partial work done within the framework of the EDA Siramis II project focused on magnetic signature reproduction of ships. Reproduction is understood here as the ability to determine the magnetic anomaly of the local Earth magnetic field in any direction and at any measurement depth due to the presence of the analysed object. The B-91 type hydrographic ship Zodiak was selected as the real case study. The work...
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Analysis of magnetic field distribution inside ferromagnetic thin shells during degaussing process
PublicationAnalysis of the demagnetization of a large ferromagnetic object like a ship, was conducted. The approximate mathematical model in the form of a long cylindrical shell of constant magnetic permeability was applied. The discrete degaussing winding was assumed and the current density and magnetic flux density distribution in the ferromagnetic shell wall were determined. Based on the frequential and temporal analysis the recommended...
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The Magnetic Fluid Seals Research Results vs. Kelvin-Helmholtz (K-H) instability and Preliminary Conclusions
PublicationIn the article a magnetic-fluid seals durability research and the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are: critical pressure, critical motion velocity and...
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Magnetic field gradient as the most useful signal for detection of flaws using MFL technique
PublicationThe magnetic flux leakage (MFL) technique is extensively used for detection of flaws as well as for evaluation of their dimensions in ferromagnetic materials. However, proper analysis of the MFL signal is hindered by the MFL sensor velocity causing distortions of this signal. Traditionally measured components of the MFL signal are particularly sensitive to the scanning velocity. In this paper, an another signal – the gradient of...
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First-order magnetic transition in single-crystallineCaFe2As2detected byA75snuclear magnetic resonance
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Magnetic Silica Nanotubes: Synthesis, Drug Release, and Feasibility for Magnetic Hyperthermia
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Zero phase shift digital filtering for assessment of exposure to non-sinusoidal magnetic fields
PublicationAccuracy of assessment of human body exposure to magnetic fields is affected by several uncertainty sources. One of them is estimation of the total exposure to non-sinusoidal fields. Standard methods can be implemented using analogue or digital filters that introduce a phase shift that affect the result of total exposure level estimation. The paper presents a new method that allows performing more precise assessment of exposure...
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Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands
PublicationCoordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work...
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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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Chapter 2: Modelling and analysis of rotor with magnetic bearing system
PublicationThe paper is concerned with rotor magnetic bearing system modelling. Such system is a relatively complex electromechanical system and can be considered as typical mechatronic one. The port-based modelling of physical systems has been used to obtain discrete-continuous model of considered system. Proposed approach enables to obtain reduced low-order lumped parameter representation of the system including gyroscopic interactions....
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Independent dynamics of slow, intermediate, and fast intracranial EEG spectral activities during human memory formation
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Flow structure, heat transfer and scaling analysis in the case of thermo-magnetic convection in a differentially heated cylindrical enclosure
PublicationThe experimental, numerical and scaling analysis in the case of thermo-magnetic convection in a thermosyphon-like enclosure filled with a paramagnetic fluid is presented. Visualization of temperature field together with the numerical simulation gave an information about the flow structure, which indicated “finger-like” structures of hot and cold streams advecting each other. Their number depended on the Rayleigh number and also...
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Evaluation of the impact of geometry and plastic deformation on the stray magnetic field around the bone shaped sample
PublicationInfluence of two factors: the variable cross-section and the localized plastic deformation, which affect the stray magnetic field profile of a ferromagnetic sample have been studied. Evaluation of an effect size is based on the analysis of the stray magnetic field component which is tangential to the longest dimension of a sample. However, in order to describe the nature of the stray magnetic field, the normal component (perpendicular...
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The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence
PublicationWe address the question of the role of quantum correlations beyond entanglement in the context of quantum magnetometry. We study the evolution of the rescaled variant of the geometric quantum discord of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results
PublicationThe edge criteria for magnetic-fluid seals durability research are critical for the seal'stechnological usefulness. The magnetic fluid seal technology in water is much moredifficult technological problem in comparison to gas or vacuum environment. There isalways problem with immediate contact between magnetic fluid and the environmentaluninspected liquids. In the paper are presented ways of experiments definitions carried outwith...
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The application of magnetic fluids in sealing nodes designed for operation in difficult conditions and in machines used in sea environment
PublicationPresented in article MF seals are being researched for sea technology purposes due to their excellent tightness and low resistance of motion. These features are most valuable for ring propellers and ship's main propeller shaft. There are more reasons why technologists payf significant attention for various MFseals applications in their difficult operating conditions. For instance, an advanced pumping systems are designed with contactless...
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The application of magnetic fluids in sealing nodes designed for operation in difficult conditions and in machines used in sea environment
PublicationPresented in article MF seals are being researched for sea technology purposes due to their excellenttightness and low resistance of motion. These features are most valuable for ring propellers and ship'smain propeller shaft. There are more reasons why technologists payf significant attention for various MFseals applications in their difficult operating conditions. For instance, an advanced pumping systemsare designed with contactless...
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Quasi-one-dimensional exchange interactions and short-range magnetic correlations in CuTeO4
PublicationCuTeO4 has been proposed as a crystallographically distinct, yet electronic structure analog, of the superconducting cuprates. Here, we present a detailed characterization of the physical properties of CuTeO4 to address this proposal. Fitting of magnetic susceptibility data indicates unexpected quasi-one-dimensional, antiferromagnetic correlations at high temperature, with a nearest-neighbor Heisenberg exchange of 1=164(5) K....
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Synthesis of CoFe2O4 Nanoparticles: The Effect of Ionic Strength, Concentration, and Precursor Type on Morphology and Magnetic Properties
PublicationThe present study highlights the effect of metal precursor types (SO4 2¯, Cl¯, and NO3¯), their concentration, and the influence of ionic strength of reaction environment on the morphology, surface, and magnetic properties of CoFe2O4 particles. The magnetic nanoparticles were obtained by chemical coprecipitation in alkaline medium at increasing metal concentration in the range of 0.0425 mol·dm-3 to 0.17 mol·dm-3 and calcination...
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Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture
PublicationThe charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and...
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Magnetic signature reproduction of ferromagnetic ships at arbitrary geographical position, direction and depth using a multi-dipole model
PublicationThe reproduction of magnetic signatures is an important issue concerning the safety of ship traffic, as well as the identification and classification of vessels. Moreover, military applications of magnetic signatures and their reproduction refer to the activation or protection against activation of magnetic naval mines. Previous works on this subject focused on recording and replicating the signatures under the same conditions...