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Wyniki wyszukiwania dla: magnetic flux leakge
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Improved methods for stator end winding leakage inductance calculation
PublikacjaCalculating the stator end-winding leakage inductance, taking into account the rotor, is difficult due to the irregular shape of the end-winding. The end-winding leakage may distribute at the end of the active part and the fringing flux of the air gap. The fringing flux belongs to the main flux but goes into the end-winding region. Then, not all the magnetic flux occurring in the end region is the end-winding leakage flux. The...
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Magnetic properties of ferromagnetic Pu2Pt3Si5
PublikacjaThe structural, magnetic, and thermodynamic properties of a new plutonium based compound, Pu2Pt3Si5, are reported. Single crystals produced by a Sn-flux technique have been analyzed showing a ferromagnetic behavior at 58 K. Pu2Pt3Si5 crystallizes in the U2Co3Si5-type orthorhombic Iabm structure (s.g. 72) with atomic parameters a = 9.9226(2) Å, b = 11.4436(2) Å and c = 6.0148(1) Å. The effective (leff 0.74 lB/Pu) and saturated (rsat...
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Simplified saturation modelling in three-leg power transformer for the system stability analisys
PublikacjaThe paper presents a simplified method for modelling non-linearity of the magnetic circuit of the power transformer. The saturation effect is implemented by describing the self and mutual inductances as a function of the magnetic flux. The most important element of this function is the saturation coefficient which is calculated based on transient state during the unloaded transformer switch on. The transformer model is described...
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Stress anisotropy characterisation with the help of Barkhausen effect detector with adjustable magnetic field direction
PublikacjaIn the paper we describe a novel apparatus for the measurement of the Barkhausen noise (BN) angular dependence, which in turn may be indicative of the stress induced anisotropy of magnetic properties. Such dependence can be further used for the stress distribution evaluation. The change of magnetization direction in the material is obtained by varying the magnetic flux density in two perpendicular yokes of the apparatus. We present...
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Growth, Crystal Structure and Magnetic Characterization of Zn-Stabilized CePtIn4
PublikacjaThe 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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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublikacjaThe 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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The influence of the geographic positioning system error on the quality of ship magnetic signature reproduction based on measurements in sea conditions
PublikacjaIn previous studies, the authors performed the magnetic signature reconstruction of the marine ship Zodiak as part of the measurement campaign focused on recording magnetic data and the relative position of a ship during its passage over a magnetometer immersed on the testing ground. A high degree of representation of the magnetic signature was obtained. However, the recorded measurement data revealed new patterns of the multidipole model...
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Determination of leakage inductances of multi-winding and single-phase transformer
PublikacjaThis paper presents the method for determination of leakage inductances of single-phase and multi-winding transformer. The matrix of leakage inductances takes into account leakage self and also leakage mutual magnetic couplings. It is assumed that there is a flux common to all windings and several leakage fluxes referred to a particular winding. The flux linkages of each coil needed fo calculation of leakage inductances was computed...
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Lagrangian model of an isolated dc-dc converter with a 3-phase medium frequency transformer accounting magnetic cross saturation
PublikacjaThis article presents a nonlinear equivalent circuit model of an isolated dc-dc converter with a 3-phase medium frequency transformer. The model takes into account the magnetic cross saturation of the 3-phase core-type magnetic circuit. The model is suitable in detailed electromagnetic transient simulations of power systems involving isolated dc-dc converters. The model is developed using the Lagrange energy method. It involves...
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BADANIE WPŁYWU INDUKCJI REMANENCJI NA STAN PRZEJŚCIOWY JEDNOFAZOWEGO UKŁADU TRANSFORMATOROWEGO
PublikacjaW referacie przedstawiono wyniki badań eksperymentalnych i symulacyjnych wpływu indukcji remanencji w rdzeniu transformatora jednofazowego na jego stan przejściowy przy jego pracy jałowej. Badany obiekt jest układem transformatorowym o dwóch uzwojeniach nawiniętych na zwijanym z blachy anizotropowej rdzeniu w kształcie toroidu. Doświadczenia eksperymentalne polegały na rozładowywaniu kondensatora przez uzwojenie strony pierwotnej...
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Measurement Campaign and Mathematical Model Construction for the Ship Zodiak Magnetic Signature Reproduction
PublikacjaThe 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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Simulation of the Remanence Influence on the Transient States of the Single-Phase Transformer Including Feedback Preisach Model
PublikacjaThis paper presents the results of the experimental and simulation investigation concerning the influence of remanence in the core of a single-phase transformer at the no-load transient state. Experimental studies consisted of the discharge of the capacitor through the primary winding at several different values of the residual magnetic flux. The paper presents a model of the transformer test system, taking into account the magnetic...
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Separation of the effects of notch and macro residual stress on the MFL signal characteristics
PublikacjaMagnetic flux leakage (MFL) distribution for three configurations of samples has been investigated in order to study the influence of notch and plastic deformation separately as well as together. Samples have been made of S355 steel. The MFL signal measurements were carried out along the longest dimension of the sample over a length of 120 mm. Two components of magnetic field were measured: 1) tangential to the main axis and 2)...
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Finite Element Method Applied in Electromagnetic NDTE: - A Review
PublikacjaThe paper contains an original comprehensive review of finite element analysis (FEA) applied by researchers to calibrate and improve existing and developing electromagnetic non-destructive testing and evaluation techniques, including but not limited to magnetic flux leakage (MFL), eddy current testing, electromagnetic-acoustic transducers (EMATs). Premium is put on the detection and modelling of magnetic field, as the vast majority...
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Evolution of Physical Properties of RE 3 Ni 5 Al 19 Family (RE = Y, Nd, Sm, Gd, Tb, Dy, Ho, and Er)
PublikacjaSingle crystals of RE3Ni5Al19 series (RE = Y, Nd, Sm, Gd, Tb, Dy, Ho, and Er) are grown using the Al self-flux method. The crystal structure is examined by both single crystal and powder X-ray diffraction. Physical properties are studied for the first time for RE3Ni5Al19 (RE = Y, Nd, Gd, Tb, Dy, Ho, and Er) by means of magnetic susceptibility, electrical resistivity, and heat capacity measurements. Complex magnetic behaviors, with...
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A finite element analysis of thermal energy inclination based on ternary hybrid nanoparticles influenced by induced magnetic field
PublikacjaThe use of hybrid nanoparticles to improve thermal processes is a key method that has implications for a variety of interventions utilized in many sectors. This paper aimed to look into the impacts of ternary nanoparticles on hyperbolic tangent materials to establish their thermal characteristics. Flow describing equations have been explored in the presence of heat production, non-Fourier heat flux, and an induced magnetic field....
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Crystal structure and low-energy Einstein mode in ErV2Al20 intermetallic cage compound
PublikacjaSingle crystals of a new ternary aluminide ErV2Al20 were grown using a self-flux method. The crystal structure was determined by powder X-ray diffraction measurements and Rietveld refinement, and physical properties were studied by means of electrical resistivity, magnetic susceptibility and specific heat measurements. These measurements reveal that ErV2Al20 is a Curie-Weiss paramagnet down to 1.95 K with an effective magnetic...
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Selected dynamic properties of adaptive proportional observer of induction motor state variables
PublikacjaThis paper presents problems related to the design and the stability of adaptive proportional observer which is used for estimation of magnetic flux and motor speed in sensorless control systems of induction motor. The gain matrix of the observer was chosen by genetic algorithm and alternatively by pole placement method. It has been shown that adaptive proportional observer is stable if the...
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Crystal growth and properties of a binary intermetallic ZrBi2 compound
PublikacjaSingle crystals of ZrBi2 were grown by a self-flux method. The material adopts TiAs2 structure type with lattice parameters: a = 10.233(4) Å, b = 15.581(2) Å, c = 3.994(5) Å. Crystals of ZrBi2 were studied by means of magnetic susceptiblity, specific heat and resistivity measurements. The compound reveals a metallic-like behavior (RRR = 30). The Sommerfeld coefficient equals γ = 1.59(16) mJ mol-1 K-2 and Debye temperature ΘD =...
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Nonlinear Interaction of Magnetoacoustic Modes in a Quasi-Isentropic Plasma Flow
PublikacjaThe nonlinear interaction of magnetoacoustic waves in a plasma is analytically studied. A plasma is an open system. It is affected by the straight constant equilibrium magnetic flux density forming constant angle with the wave vector which varies from 0 till . The nonlinear instantaneous equation which describes excitation of secondary wave modes in the field of intense magnetoacoustic perturbations is derived by use of projecting....
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Chemical Pressure Tuning Magnetism from Pyrochlore to Triangular Lattices
PublikacjaGeometrically frustrated lattices combined with magnetism usually host quantum fluctuations that suppress magnetic orders and generate highly entangled ground states. Three-dimensionally (3D) frustrated magnets generally exist in the diamond and pyrochlore lattices, while two-dimensionally (2D) frustrated geometries contain Kagomé, triangular, and honeycomb lattices. In this work, we reported using chemical pressure to tune the magnetism...
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Models of Brushless Synchronous Generator for Studying Autonomous Electrical Power System
PublikacjaThis is a PhD dissertation. The work presented in this monograph was carried out at the Department of Power Electronics and Electrical Machines, Faculty of Electrical and Control Engineering at the Gdansk University of Technology. Developed during the research models of brushless synchronous generator ware verified using FEM based simulations and measurements conducted on the prototype generator. The main focus of the research...
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A review on analytical models of brushless permanent magnet machines
PublikacjaThis study provides an in-depth investigation of the use of analytical and numerical methods in analyzing electrical machines. Although numerical models such as the finite-element method (FEM) can handle complex geometries and saturation effects, they have significant computational burdens, are time-consuming, and are inflexible when it comes to changing machine geometries or input values. Analytical models based on magnetic equivalent...
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Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublikacjaSpatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H2/Ar/CH4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along...
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Structure redetermination, transport and thermal properties of the YNi3Al9 compound
PublikacjaSingle crystals of completely ordered variant of the YNi3Al9 compound were grown by self-flux method with excess of aluminum. The crystal structure of the title compound was redetermined from single crystal X-ray diffraction data. The structure adopts ErNi3Al9 type, space group R32, parameters of the unit cell a = 7.2838(2) Å, c = 27.4004(8) Å. The growth of relatively large single crystals of the YNi3Al9 compound, having completely...
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Flux
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Superconductivity in CaBi2
PublikacjaSuperconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is DC/gTc = 1.41, confirming bulk superconductivity;...
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Crystal structure and physical properties of AePd1-xP1+x (Ae = Ca, Sr)
PublikacjaWe report the discovery of two new compounds AePd1-xP1+x (Ae = Ca, Sr) crystallized in different hexagonal structures. Single crystals of AePd1-xP1+x (Ae = Ca, Sr) are obtained using the Bi-flux method. Crystallographic analysis by both powder and single crystal X-ray diffraction shows that CaPd1-xP1+x crystallizes in a non-centrosymmetric hexagonal structure with the space group P-6m2 (No.187) and lattice parameters a = b = 4.0391(9)...
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Superconducting SrSnP with Strong Sn–P Antibonding Interaction: Is the Sn Atom Single or Mixed Valent?
PublikacjaThe large single crystals of SrSnP were prepared using Sn self-flux method. The superconductivity in the tetragonal SrSnP is observed with the critical temperature of ∼2.3 K. The results of a crystallographic analysis, superconducting characterization, and theoretical assessment of tetragonal SrSnP are presented. The SrSnP crystallizes in the CaGaN structure type with space group P4/nmm (S.G. 129, Pearson symbol tP6) according...
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Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
PublikacjaThe seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice...
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FURTHER REMARKS ON THE NEO-CLASSICAL NAVIER-STOKES EQUATIONS
PublikacjaThe seminal Navier-Stokes equations have been stated yet before creation of principles of thermodynamics and the first and second laws. In the literature there is the common opinion that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of “working fluid” which is able to describe transformation of “ heat” into “work” and vice versa. Therefore, in the paper, a new exposition of thermodynamically...
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Modelling and analysis of medium frequency transformers for power converters
PublikacjaThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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The home-made in situ passive flux sampler for the measurement of monoterpene emission flux: preliminary studies
PublikacjaThe paper presents the construction and metrological characteristics of the home-made in situ passive flux sampler, an analytical tool representing small-scale emission chambers working in situ and passively sampling analytes from the gaseous phase. The sorption element was a cylindrical container made of stainless steel net, packed with a carbon sorbent bed-graphitized charcoal, Carbograph 4 (35/50mesh). The recommended working/exposure...
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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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Analysis of leakage flux in deenergized transformer
PublikacjaThe article presents the numerical analysis of the magnetic field that occurs around the transformer after it has been switched off. The purpose of this analysis was to determine if it is possible to define the residual fluxes in the legs of transformer based on the measurements of this field. These studies have allowed us to determine the quantity and location of the sensors. The influence of the Earth's magnetic field has also...
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MAGNETIC RESONANCE IN CHEMISTRY
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Magnetic disturbances caused by magnetic contamination of plastics
PublikacjaIn the study of low magnetic fields precision magnetometers working in a differential system are used. Two optically pumped magnetometers working in a differential system allow for precise measuring of disturbances in the magnetic field. In order to attain high accuracy of magnetic field measurement, it is necessary to use appropriate materials for the construction of a magnetometric system, particularly of those located closely...
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A device for measuring heat flux on a rocket skin surface
PublikacjaA novel method for measuring heat flux on a surface is presented. It is an extensive upgrade of currently known heat flux sensors used mostly in civil engineering. As the thermal environment of launchers, especially sounding rocket can have an enormous negative effect on payload, careful considerations have to be taken in the process of preparing insulation. Usually, thermal data provided by the launch vehicle manufacturer is limited...
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Controlling the europium oxidation state in diopside through flux concentration
PublikacjaThis paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting...
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Assessment of absorbability of seamless flux cored wires stored in extreme conditions
PublikacjaWater absorption tests by gravimetric method of three specimens of seamless rutile flux cored wires for flux cored arc welding were carried out. Examined wires are characterized by varied absorbability (Wg is ranged from 0.03 to 0.11% after 200 h of moisturizing).
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Novel adaptive flux observer for wide speed range sensorless control of induction motor
PublikacjaA new adaptive flux observer of induction motor is presented in the paper. The Lyapunov theory is utilized for derivation of the adaptation law of rotor flux angular speed, which acts as unknown parameter in an augmented induction motor model. In the field weakening region, where stray fluxes are comparable with rotor flux magnitude, the air-gap flux stabilization is proposed. An air-gap flux multiscalar model is derived for stator...
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Nonlinear control of five phase induction motor with synchronized third harmonic flux injection
PublikacjaThe paper deals with the novel control system for five phase induction motor (IM) that enables the injection of the rotor flux 3rd harmonic component. Two multiscalar models are transformed from the 1-1 and 2-2 vector models developed in the 1st and 3rd harmonic planes. Based on the obtained multiscalar models the synthesis of dual multiscalar control is established. The obtained two multiscalar control systems can independently...
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Effects of Storing Flux-Cored Wires under Various Conditions
PublikacjaWelding processes involving the use of flux-cored wires are becoming increasingly popular, particularly in shipbuilding as well as in off-shore and civil engineering. The article presents characteristics of the welding process, its areas of application as well as advantages and disadvantages (e.g. necessity of ensuring appropriate conditions for the storage of filler metal wires). The satisfaction of quality-related requirements...
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Rotor-Flux Vector based Observer of Interior Permanent Synchronous Machine
PublikacjaThe sensorless control system of the interior permanent magnet machine is considered in this paper. The control system is based on classical linear controllers. In the machine, there occurs non-sinusoidal distribution of rotor flux together with the slot harmonics, which are treated as the control system disturbances. In this case, the classical observer structure in the (d-q) is unstable for the low range of rotor speed resulting...
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Preliminary studies of seamless flux cored wires stored in extreme conditions
PublikacjaIn the paper preliminary experimental studies of flux cored wires moisturized under controlled conditions are described. Three seamless wires of different grades have been placed in environmental chamber and moisturized in extremely adverse conditions (temperature T = 60° C, relative humidity H = 90%) for 240 hours. During this time measurements of weight gain and observations of surface of wires have been carried out. Also diffusible...
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Exploring the trends in flux-cored arc welding: scientometric analysis approach
PublikacjaFlux-cored arc welding (FCAW) is a universal group of welding methods in terms of the scope of application and automation possibilities, the share of which in various industries in many countries is still increasing. The paper presents the results of bibliographic analyses (scientometric analysis with the use of VOSviewer, Bibliometrix and CitNetExplorer tools) of a data set of 993 publications indexed in the Web of Science database...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublikacjaThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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Spectroscopic and magnetic studies of highly dispersible superparamagnetic silica coated magnetite nanoparticles
PublikacjaSuperparamagnetic behavior in aqueously well dispersible magnetite core-shell Fe3O4@SiO2 nanoparticles is presented. The magnetic properties of core-shell nanoparticles were measured with use of the DC, AC magnetometry and EPR spectroscopy. Particles were characterized by HR-TEM and Raman spectroscopy, showing a crystalline magnetic core of 11.5 ± 0.12 nm and an amorphous silica shell of 22 ± 1.5 nm in thickness. The DC, AC magnetic...
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Model of ship's magnetic signature
PublikacjaShips made of ferromagnetic metals interfere with Earth's magnetic field in their surrounding. The disturbance of the magnetic field makes possible localization and even identification of the ship, which could determine a threat to the ship. The measurement of the magnetic field around the ship enables to determine its magnetic signature. The paper presents a multidipoles model of the ship magnetic field, which allows to determine...
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Investigation of magnetic order in a new intermetallic compound Nd2PtGe3
PublikacjaIn the present study we report a successful synthesis of the new intermetallic compound Nd2PtGe3 by an arc-melting method. The powder X-ray diffraction analysis indicates that this compound crystallizes in an disordered variant of the AlB2-type structure (space group P6/mmm, no. 191) with lattice parameters a = 4.2455 Å and c = 4. 1933 Å. The compound exhibits a cluster-glass transition below Tf = 2.9 K, characterized through ac...
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Insight into (Electro)magnetic Interactions within Facet-Engineered BaFe12O19/TiO2 Magnetic Photocatalysts
PublikacjaA series of facet-engineered TiO2/BaFe12O19 composites were synthesized through hydrothermal growth of both phases and subsequent deposition of the different, faceted TiO2 nanoparticles onto BaFe12O19 microplates. The well-defined geometry of the composite and uniaxial magnetic anisotropy of the ferrite allowed alternate interfaces between both phases and fixed the orientation between the TiO2 crystal structure and the remanent...
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Magnetic photocatalysts for water treatment
PublikacjaThe concept of magnetic photocatalysts with separation function requires ferromagnetic material with high magnetic susceptibility to an external magnetic field to enable recycling of composite nanoparticles. Currently, much attention is devoted to functionalization of photocatalyst using MFe2O3, where M =Fe, Zn, Co, Mn. However direct contact between photocatalyst and magnetic iron oxide particles leads to photodissolution of iron...
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Analysis of aircraft magnetic interference
PublikacjaThe magnetometric method is used among other things on mobile platforms (planes, helicopters) in military systems and in geological research. Optically-pumped and SQUID magnetometers are used in magnetic systems on airplanes. To be able to attain the sensitivity of modern magnetometers in flight, it is important that maneuver-related magnetic interference effects be minimized. The mathematical model of an aircraft as a source of...
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Analysis of aircraft magnetic interference
PublikacjaThe magnetometric method is used among other things on mobile platforms (planes, helicopters) in military systems and in geological research. Optically-pumped and SQUID magnetometers are used in magnetic systems on airplanes. To be able to attain the sensitivity of modern magnetometers in flight, it is important that maneuver-related magnetic interference effects be minimized. The mathematical model of an aircraft as a source of...
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Magnetic signatures of land vehicles
PublikacjaThe results of numerical simulations of the magnetic field surrounding of land vehicles' models have been presented in this paper. Vehicle containing of ferromagnetic elements distorts the Earth's magnetic field. This distortion can be measured by magnetometers. It is possible to detect and identify an object on the basis of its magnetic signature.
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Multidipoles model of ship's magnetic field
PublikacjaShips made of ferromagnetic metals interfere with Earth's magnetic field in their surrounding. The disturbance of the magnetic field makes possible localization and even identification of the ship, which could determine a threat to the ship. The measurement of the magnetic field around the ship enables to determine its magnetic signature. The paper presents a multidipoles model of the ship magnetic field, which allows to determine...
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Multidipoles model of ship's magnetic field
PublikacjaShips made of ferromagnetic metals interfere with Earth's magnetic field in their surrounding. The disturbance of the magnetic field makes possible localization and even identification of the ship, which could determine a threat to the ship. The measurement of the magnetic field around the ship enables to determine its magnetic signature. The paper presents a multidipoles model of the ship magnetic field, which allows to determine...
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Augmented speed control scheme of dual induction motors with mutual flux angle control loop
PublikacjaThis paper proposes an augmented speed control scheme of dual induction motors fed by a five-leg voltage source inverter (VSI) with a common/shared-leg. An additional control loop is proposed here and based on the mutual flux angle – the difference between flux angular positions of the IMs. The main purpose of this research is to minimize the energy losses in the common inverter leg by controlling the mutual flux angle, at equal...
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Modelling of the Heat Flux Density Distribution for Laser Beam Welding
PublikacjaGreat interest of the laser beam welding in industry is a new theoretical task, making planning the welding procedure specification and the quality control of welded joints easier. Estimating and calculating the dimensions of a weld pool and temperature distribution near weld mainly concern heat source modelling. In the presented work calculations of welding pool shape and thermal field for cylindrical-powered-normally model of...
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Enhancement of the Magnetic Coupling in Exfoliated CrCl 3 Crystals Observed by Low‐Temperature Magnetic Force Microscopy and X‐ray Magnetic Circular Dichroism
PublikacjaMagnetic crystals formed by 2D layers interacting by weak van der Waals forces are currently a hot research topic. When these crystals are thinned to nanometric size, they can manifest strikingly different magnetic behavior compared to the bulk form. This can be the result of, for example, quantum electronic confinement effects, the presence of defects, or pinning of the crystallographic structure in metastable phases induced by...
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Diffusible Hydrogen Control in Flux Cored Arc Welding Process
PublikacjaOne of the types of hydrogen degradation of steel welded joints is cold cracking. The direct cause of the formation of cold cracks is simultaneous presence of hydrogen, residual stresses and brittle structure. The way of preventing the occurring of degradation is to eliminate at least one of these factors. Practice has shown that the best solution is to control the amount of hydrogen in deposited metal. In this paper an experimental...
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Magnetic properties of α-KCoPO4 compound with a chiral polar crystal structure
PublikacjaWe have obtained polycrystalline samples of a metastable α variant of KCoPO4 by low temperature (350–400 °C) solid state metathesis reaction of potassium oxalate and ammonium cobalt orthophosphate. The material crystallizes in a polar chiral structure (sg. P63, no. 173). Measurements of magnetic properties reveal antiferromagnetic interactions and no ordering observed down to T = 1.9 K, well below the Weiss temperature |Θcw| =...
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The Dynamic Model of Magnetic Hysteresis
PublikacjaThis paper presents the scalar dynamic magnetic hysteresis model based on the Preisach theory. The important role in this theory played hysteresis operator states. The changes of these operators` states are not immediate in the dynamic model but they are a function of time and parameter k representing the magnetic properties of the material. In this paper the transient state of the hysteresis operator is defined by the nonlinear...
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Anna Zielińska-Jurek dr hab. inż.
OsobyResearch work on photocatalysis by Prof. Anna Zielinska-Jurek started in 2006 at Gdansk University of Technology (Poland), including 3-month research stay at Hokkaido University, Training School “Environmental Applications of TiO2 Photocatalysis” at the University of Oulu in Finland granted by COST Program and Training School “NanoBiophotonics” at the Beckmann Institute, Urbana-Champaign in the USA granted by University of Illinois....
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Magnetic Resonance
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Application of magnetic nanoparticles for magnetic solid-phase extraction in preparing biological, environmental and food samples
PublikacjaThe need to obtain meaningful results as the basis for determining the content of trace amounts of analytes has become the driving force behind the development of modern analytical techniques, including sample-preparation techniques, such as solid-phase extraction (SPE). Recently, great interest was aroused in the use of magnetic nanoparticles (MNPs) in SPE. These materials exhibit high selectivity, and, in small amounts, can provide...
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Magnetic nanocomposites for biomedical applications
PublikacjaTissue engineering and regenerative medicine have solved numerous problems related to the repair and regeneration of damaged organs and tissues arising from aging, illnesses, and injuries. Nanotechnology has further aided tissue regeneration science and has provided outstanding opportunities to help disease diagnosis as well as treat damaged tissues. Based on the most recent findings, magnetic nanostructures (MNSs), in particular,...
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Analysis of magnetic field of Helmholtz's coils
PublikacjaThe 3-axis fluxgate magnetometer requires conducting a precise calibration in the magnetic field whose value is determined and which is characterized by the high uniformity of the distribution of the field, especially along the axis of the sensors. The generation of the magnetostatic field characterized by the high uniformity, can be achieved by using the Helmholtz's coils. The requirements of the uniformity of distribution of...
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AUGMENTATION OF THE CRITICAL HEAT FLUX IN WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublikacjaThe main aim of the proposed study is therefore recognition of the phenomena accompanying nucleate boiling crisis of selected nanofluids during boiling on horizontal tubes of various outside diameters. Of particular interest is impact of contact angle and tube diameter on the value of critical heat flux. The results obtained should give more light on the nature of nucleate boiling crisis and will serve as a basis for future theoretical...
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Effect of Storage Conditions of Rutile Flux Cored Welding Wires on Properties of Welds
PublikacjaThe influence of storage locations of two grades of rutile flux cored welding wires on their surface condition and the strength of the welds made with them were studied. Wires were stored in real urban conditions (Gdańsk and Katowice) for 1 month, simultaneously recording changes in conditions: temperature and relative humidity of the environment. Visual tests of wires in the delivered and stored condition as well as visual and...
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Disturbances of magnetic field in surrounding of mobile, metalic plate
PublikacjaThe uniform magnetic field of the Earth in the surrounding of a mobile, metalic object undergoes deformation by eddy currents. The influence of the moving conducting object on total magnetic field of the Earth depends on the object's shape, position and speed of the changes relative to the magnetic field's vector of the Earth as well as the electric conductivity and the relative magnetic permeability of the material. The disturbances...
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Characterization of glucoamylase immobilized on magnetic nanoparticles
PublikacjaMagnetic support was prepared by precipitation from an alkaline solution of divalent and trivalent iron ions and subsequently was modified with 3-aminopropyltriethoxysilane. FTIR analysis showed existence of a new Si-O-Fe bond in obtained particles. Scanning electronic microscopy images shows that the nanoparticles of all samples have particle size below 30 nm. Glucoamylase AMG 300L was immobilized onto the modified magnetic support...
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Mathemathical model of radial passive magnetic bearing
PublikacjaIn the article mathematical radial model of passive magnetic bearings to ocean engineering units has been presented. The units application in underwater thrusters should increase propulsion systems durability and gives lower maintenance costs. The rotor of electric motor is hanging in magnetic field taken from radial passive magnetic bearings. However axial direction maintenance must be controlled with electromagnets and their...
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The Influence of Permanent Magnet Length and Magnet Type on Flux-control of Axial Flux Hybrid Excited Electrical Machine
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MAKING OF FERROMAGNETIC ELLIPTICAL SHELL IN TRANSVERSE MAGNETIC
PublikacjaA ferromagnetic object, located in the Earth’s magnetic field, changes its distribution. Through measuring such disturbances, one can locate the object and destroy it. To conceal the object, a special winding is placed inside its ferromagnetic shell, and its task is to eliminate the disturbances in the distribution of the Earth’s magnetic field.
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NEW DESIGNS OF MAGNETIC FLUID SEALS FOR RECIPROCATING MOTION
PublikacjaT he operating conditions of magnetic fluid seals during reciprocating motion are so different from those observed in rotating motion that the use of their conventional structures for reciprocating motion seals yields no good results. The analysis of the sealing mechanism of magnetic fluid seals in reciprocating motion shows that the operation of these seals is affected by the carry-over phenomenon and magnetic fluid...
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Diffusible hydrogen management in underwater wet self-shielded flux cored arc welding
PublikacjaThis article reports the effect of underwater wet welding parameters and conditions on the diffusible hydrogen content in deposited metal for welding with a self-shielded flux cored wire. The diffusible hydrogen content in deposited metal was determined using the glycerin method according to the Plackett-Burman design determining the significance of the effect of the stick out length, welding current, arc voltage, travel speed...
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Low-Dimensional Magnetic Semimetal Cr0.65Al1.35Se3
PublikacjaWhile exploring novel magnetic semiconductors, the new phase Cr0.65Al1.35Se3 was discovered and characterized by both structural and physical properties. Cr0.65Al1.35Se3 was found to crystallize into orthorhombic CrGeTe3-type structure with space group Pnma (no. 62). Vacancies and mixed occupancies were tested, and the results show that one of the 4c sites accommodates a mixture of Cr and Al atoms, while the other 4c site is fully...
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Small-scale passive emission chamber for screening studies on monoterpene emission flux from the surface of wood-based indoor elements
PublikacjaAnalysis of literature data published in the last fewyears leads to the conclusion that in the process of assessment of emission flux of organic compounds emitted from different types of equipment and finishing materials, new types of devices, among which small-scale passive emission chambers for the performance of in-situ research are designed and applied on a larger scale. These devices can be successfully used for the assessment...
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Disturbances of Earth magnetic field caused by eddy currents of airplane
PublikacjaThe uniform magnetic field of the Earth in the surrounding of a mobile, metallic object undergoes deformation by eddy currents. The influence of the moving, conducting object on the Earth's total magnetic field depends on the object's shape, position and speed of the changes relative to the magnetic field vector of the Earth, as well as the electric conductivity and the relative magnetic permeability of the material. Disturbances...
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Detection of ferromagnetic objects in local magnetic anomaly of the Baltic Sea
PublikacjaIn geological researches several kinds of methods are applied to discovering the natural resources. Planes, helicopters and UAVs (UnmAnned Vehicle) are used in researches in large areas. The gravity, electromagnetic and magnetic methods, which are used in geological researches, are presented in this paper. The special attention was paid to magnetic systems installed on mobile platforms. The magnetic field of the Earth obtained...
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Magnetic study of nanocrystalline 0.95MnO/0.05ZnO
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Disturbances of magnetic field of plane caused by eddy currents
PublikacjaResults of the numerical analysis of the magnetic disturbances of a plane caused by eddy currents induced in conducting elements of the plane were presented in this paper. Magnetic disturbances of the object's model were carried out in Opera 3D.
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Performance of lubricated sliding contact in magnetic field
PublikacjaResults of experimental studies concerning theinfluence of permanent magnetic field on wear of lubricatedsliding contact operating at short stroke and highfrequency are presented. It was found that horizontalmagnetic is affecting performance of the contact. Thejagged delamination regions produced in the presence of amagnetic field can be regarded as easily undergoing oxidisationbecause oxygen is readily adsorbed there. Magneticfield...
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The influence of compensate coils on own ship magnetic field
PublikacjaA ferromagnetic object placed in the earth magnetic field causes a local disturbance in this field distribution. The field distribution disturbance is a function of many arguments like the dimensoins and shape of the object, its ferromagnetic properties ande its positon in relation to the earth magnetic field. in order to minimize the influence of this disturbance one places compensate coils on the ship. Some chosen results of...
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System of wireless magnetic sensors for detection and identification of ferromagnetic vehicles
PublikacjaThe paper presents the results of deformation of the Earth's magnetic field by land vehicles. Basing on the analysis of the shape of the magnetic field deformation, it is possible to detect and identify a vehicle. In order to eliminate the interference of the Earth's magnetic field by the environment, the measurements were performed in a differential configuration. Under a development project a wireless system of magnetic sensors...
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Eu2Mg3Bi4: Competing Magnetic Orders on a Buckled Honeycomb Lattice
PublikacjaThe honeycomb lattice and its derived variants provide information on modeling and designing quantum magnets. A novel magnetic material, Eu2Mg3Bi4, which stabilizes in a previously unknown buckled honeycomb lattice, was discovered by high-pressure and high-temperature methods. We report here on the synthesis exploration of pure single crystals, structural determination of the buckled honeycomb lattice of europium moments, and experimental observation...
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Edge effects for heat flux in fibrous composites
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Research of IPM electrical machine with flux barriers
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Modeling of Axial Flux Permanent Magnet Generators
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Magnetic instrumentation and other applications of magnets in NOTES
PublikacjaModern surgery is developing towards a minimally invasive approach. To minimize the trauma the number of ports is either limited as in single incision laparoscopic procedures or ports are introduced through natural orifices as in nat- ural orifice translumenal endoscopic surgery (NOTES). To provide surgeons with appropriate instrumentation novel technologies are employed involving magnets. This article summarizes the theoretical...
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Magnetic deep eutectic solvents – Fundamentals and applications
PublikacjaMagnetic deep eutectic solvents (MDES), a relatively new subclass of conventional deep eutectic solvents (DES) containing additional paramagnetic components in their structure. MDES exhibit a strong response toward external magnetic fields, thus they can improve many industrial and analytical applications. In addition, this new group of solvents present unique physicochemical properties that can be easily tuned by selecting the...
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Analysis of magnetic disturbances of air platform caused by induced magnetisation
PublikacjaMagnetometric systems installed on air platforms like airplanes or helicopters are equipped in compensators of magnetic disturbances. Time changes of the platform's position caused generation of magnetic disturbances. The permanent and induced magnetization of ferromagnetic elements and eddy currents induced in conducting parts of the platform are sources of these disturbances. The linear model of magnetic disturbances of platforms...
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Influence of magnetic field on wear in high frequency reciprocatingsliding contacts
PublikacjaResults of experimental studies concerning the influence of permanent magnetic field on wear of dry sliding contact operating at short stroke and high frequency are presented. It was found that horizontal magnetic field with different orientations relative to the sliding direction is affecting performance of the contact. The increase in frequency of sliding reduces accumulated mass loss and lowers the surface roughness of the wear...
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Analysis of magnetic field of Hemholtz's coils and ferromagnetic objects
PublikacjaThe 3-axis fluxgate magnetometer requires conducting a precise calibration in the magnetic field whose value is determined and which is characterized by the high uniformity of the distribution of the field, especially along the axis of the sensors. The generation of the magnetostatic field characterized by the high uniformity, can be achieved by using the Helmholtz's coils. The requirements of the uniformity of distribution of...
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Electron magnetic resonance study of the Ni47Co3Mn35.5In14.5 ribbons
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Magnetic and structural phase transition in Ni50Mn35.5In14.5 ribbon
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Magnetic field effects in dye-sensitized and organic solar cells
PublikacjaThe charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. The aim of this thesis is to understand the electronic processes limiting the operation of efficient solar cells with particular emphasis on the role of electronic states endowed with magnetic dipole moment. The research work is divided into two parts. The first part deals...
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Axial-Flux Permanent-Magnet Dual-Rotor Generator for a Counter-Rotating Wind Turbine
PublikacjaCoaxial counter-rotating propellers have been widely applied in ships and helicopters for improving the propulsion efficiency and offsetting system reactive torques. Lately, the counter-rotating concept has been introduced into the wind turbine design. Distributed wind power generation systems often require a novel approach in generator design. In this paper, prototype development of axial-flux generator with a counter-rotating...