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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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Advanced Hysteretic Model of a Prototype Seismic Isolation System Made of Polymeric Bearings
PublikacjaThe present paper reports the results of acomprehensive study designed to verify the effectiveness of an advanced mathematical model in simulating the complex mechanical behaviour of a prototype seismic isolation system made of polymeric bearings (PBs). Firstly, in order to construct the seismic bearings considered in this research, a specially prepared flexible polymeric material with increased damping properties was employed....
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Barkhausen Noise Calculation by Hysteresis Model Parameters
PublikacjaPętla histerezy natężenia efektu Barkhausena wyliczono wykorzystując model histerezowy. Założono, iż straty energii na efekt Barkhausena zależą od szybkości granicy domenowej oraz od częstości występowania skoków Barkhausena. Pokazano wyliczenia wykonane dla stali Fe-Si (ziarna zorientowane w kierunku [100] względem kierunku walcowania)
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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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Hysteresis curves for some periodic and aperiodic perturbations in gases
PublikacjaEvolution of sound in a medium whose properties irreversibly vary in the course of wave propagation, is studied. For example, a gas that is a particular case of a Newtonian fluid is considered. Hysteresis curves, pictorial representations of irreversible attenuation of the sound energy, in the plane of thermodynamic states are plotted. The irreversible losses in internal energy are proportional to the total attenuation and depend...
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Hysteresis modelling of a medium frequency single-phase transformer
PublikacjaThe article describes a feedback Preisach hysteresis model equivalent circuit implementation of a medium frequency single-phase transformer being a part of a high power and high efficiency DC-DC converter. The macroscopic models of magnetic hysteresis are introduced and the feedback Preisach model is selected for further analysis. The hysteresis model is developed for a prototype transformer and the hysteresis loops are compared...
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Acoustic Hysteresis in Flows with Different Kinds of Relaxation and Attenuation
PublikacjaGraphs in the thermodynamic plane acoustic pressure versus excess acoustic density representing acoustic hysteresis, are considered as indicators of relaxation processes, equilibrium parameters of a flow, and kinds of wave exciters. Some flows with deviation from adiabaticity are examined: the Newtonian flow of a thermocon- ducting gas, the flow of a gas with vibrational relaxation, the flow of liquid electrolyte with a chemical...
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On the time behaviour of Okazaki fragments
PublikacjaW pracy wyprowadzono wzory na prawdopodobieństwo, że podczas procesu replikacji DNA w chwili t pojawi się n fragmentów Okazaki.
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Dynamics of Systems with a Discontinuous Hysteresis Operator and Interval Translation Maps
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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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Reprezentation of mechanic hysteresis in a railway track using the Preisach model
PublikacjaThis paper presents an implementation of the classic scalar Preisach model to describe the hysteresis phenomenon created in a railway track subjected to lateral (in the horizontal plane) displacements. The principles of the Preisach theory and the scalar mathematical model of the mechanical hysteresis that is based on statistically distributed modified hysteresis operators are briefly presented. This article presents the characteristic...
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Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublikacjaA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
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On Kinetic Nature of Hysteresis Phenomena in Stress-Induced Phase Transformations
PublikacjaA simplest model is developed which demonstrates that hysteresis phenomena in stress-induced phase transformations may have a kinetic nature and follow from the discrepancy between strain rate and characteristic rate of the new phase growth.
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Artificjal environment for simulation of emergent behaviour
PublikacjaPrzedstawiono opracowane środowisko dla modelowania zjawisk, w których współdziałanie wielu prostych jednostek prowadzi do powstawania złozonych struktur. Sposób oddziaływania jednostki zawarty jest w jej strukturze, która interpretowana jest poprzez specjalnie zdefiniowany język podobny do Prologu.
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Patterns of Ethical Behaviour and Decision Making.
PublikacjaW pracy przedstawiono propozycję wykorzystania wzorców programowych do opracowania wzorców etycznych, mających na celu wspomaganie prowadzącego projekt informatyczny w podejmowaniu decyzji. Ideę zilustrowano dwoma przykładami.
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Post-peak behaviour of CFST columns
PublikacjaArtykuł dotyczy zachowania pokrytycznego słupów CFST. Parametrami zmiennymi w badaniach są: wysokość słupów, grubość stalowego płaszcza, wytrzymałość betonu i stali, przyczepność między stalowym płaszczem a betonowym rdzeniem oraz sposób przykładania obciążenia. W artykule dokonano analizy wpływu tych parametrów na zachowanie pokrytyczne badanych słupów.
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Unusual behaviour of (Np,Pu)B2C
PublikacjaTwo transuranium metal boron carbides, NpB2C and PuB2C have been synthesized by argon arc melting. The crystal structures of the {Np,Pu}B2C compounds were determined from single-crystal X-ray data to be isotypic with the ThB2C-type (space group R3m, a = 0.6532(2) nm; c = 1.0769(3) nm for NpB2C and a = 0.6509(2) nm; c = 1.0818(3) nm for PuB2C; Z = 9). Physical properties have been derived from polycrystalline bulk material in the...
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Behaviour of steel columns under impact
PublikacjaOne of import issues related to the idea of sustainable society is the safety of civil engineering structures. The safety and reliability of steel structures under impact loading is among a number of different aims during the design state. The aim of this paper is to present the results of investigation focused on dynamic behaviour of steel columns under impact loading. Modal and transient dynamic analyses using Finite Element...
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A Study of Transport Behaviour of Academic Communities
PublikacjaAn important challenge to achieving sustainable university campuses is ensuring that the academic community makes sustainable transport choices. The objective of this study was to investigate the daily commuting patterns, identify the potential for change, and determine the factors and criteria affecting the transport decisions of academic communities of two universities located in Gdansk, Poland. This paper summarizes the results...
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Pseudo-superparamagnetic behaviour of bariumhexaferrite particles
PublikacjaThe effect of hexadecyltrimethylammonium bromide (CTAB) addition on the crystal structure, morphology,and magnetic properties of co-precipitated hexagonal barium ferrite was investigated. For afixed amount ofsurfactant, different Fe3+concentrations and Fe3+/Ba2+ratios were used to optimize the formation ofsingle-phase barium ferrite particles. The results indicated that the obtained ferrite particles exhibitedcoercivity changes...
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Boundary effects on behaviour of granular material
PublikacjaW artykule przedstawiono wyniki symulacji lokalizacji odkształceń w materiałach granulowanych podczas ściskania dwuosiowego. Obliczenia wykonano przy zastosowaniu metody elementów skończonych i mikropolarnego modelu hipoplastycznego. W pracy pokazano wpływ warunków brzegowych na globalne i loklane zachowanie sie materiału.
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Flock behavior and control
PublikacjaIn this paper we present the results of the Flock Behaviour and Control workshop cluster during “Shapes of Logic Conference 2015”. During the event, students got familiar with the techniques of both visual and sound real-time data processing. The second topic presented for students was behaviourbased approach of design process, mainly based on the mathematical rules set up by Craig Raynolds on the swarm behaviour. The aim of the...
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Representation of magnetic hysteresis in tape wound core using Preisach's theory
PublikacjaW referacie przedstawiono model matematyczny histerezy magnetycznej w ujęciu klasycznej teorii Preisacha. Dokonano implementacji skalarnego modelu Preisacha w odniesieniu do rdzenia zwijanego z taśmy typu ET114-27. Do symulacji różnych stanów magnetycznych rdzenia wykorzystano jedynie dane z pomiarów głównej pętli histerezy. Wyznaczono funkcję Everetta i funkcję dystrybucji Preisacha badanego rdzenia. Uzyskano ogólnie dobrą zgodność...
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Fatigue Behaviour of Sintered Duplex Stainless Steel
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Effect of ZrO2 on corrosion behaviour of chromium coatings
PublikacjaW celu zbadania wpływu cząstek ZrO2 na zachowania korozyjne powłok chromowych pokryto stal chromem z elektrolitów Cr(VI) z dodatkiem i bez ZrO2. Właściwości korozyjne osadzonych warstw zbadano w elektrolicie 0,01 mol L(-1) kwasu siarkowego plus 0,5 mol L(-1) siarczanu sodu za pomocą metody spektroskopii impedancyjnej i woltamperometrii cyklicznej. Zaproponowano elektryczny obwód zastępczy dla procesu korozji i wyznaczono pęd korozji....
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Effect of SiC on the corrosion behaviour of chromium coatings
PublikacjaWarstwy kompozytowe Cr-SiC osadzono z kąpieli zawierającej Cr(VI) oraz zielony proszek SiC. Zawartość SiC w warstwie chromowej wynosiła od 0,1-0,9% wag. Badania XPS wykazały iż SiC pokrywała warstwa SiO2, która powstała w wyniku utleniania SiC za pomocą Cr(VI). Przeprowadzono badania potencjodynamiczne i badania za pomocą spektroskopii impedancyjnej w celu określenia właściwości korozyjnych warstw Cr-SiC w środowisku kwaśnym....
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Tribological Behaviour of Copper-Graphene Composite Materials
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Identification of inertia and activity in the market behaviour of enterprises
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Experimental observations on the creep behaviour of frozen soil
PublikacjaConstitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side...
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Behaviour of water in different types of goats' cheese
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Investigation on the behaviour of imidazolium ionic liquids in the environment
PublikacjaCiecze jonowe są solami o niskiej temperaturze topnienia, które mogą zrewolucjonizować przemysł chemiczny ponieważ w wielu przypadkach oferują zarówno ekonomiczny jak i ekologiczny zysk w porównaniu z dotychczas stosowanymi technologiami. Imidazoliowe cieczejonowe należą do najczęściej stosowanych co sprawia, że mogą stanowić źródło zanieczyszczenia środowiska glebowego i wodnego. Niektóre parametry środowiskowe (np. biodegradowalność,...
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The Low Frequency Noise Behaviour of SiC MESFETs
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Modelling the time-dependent behaviour of soft soils
PublikacjaTime-dependence of soft soils has already been thoroughly investigated. The knowledge on creep and relaxation phenomena is generally available in the literature. However, it is still rarely applied in practice. Regarding the organic soils, geotechnical engineers mostly base their calculations on the simple assumptions. Yet, as presented within this paper, the rate-dependent behaviour of soft soils is a very special and important...
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Multiaxial Fatigue Behaviour of SLM 18Ni300 Steel
PublikacjaFatigue behaviour of SLM 18Ni300 steel under proportional bending-torsion loading is studied. The fatigue tests are conducted under pulsating loading conditions using tubular specimens with a transversal circular hole. Three ratios of the normal stress to shear stress are considered, namely σ/τ=4,σ/τ=2 and σ/τ = 4/3. Crack initiation sites were found for two diametrically opposite points around the hole, whose locations are governed...
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Representation of magnetic hysteresis in tape wound core using feedback Preisach model
PublikacjaThis paper presents a mathematical model for the hysteresis phenomenon in ferromagnetic tape wound core. The feedback scalar Preisach model of hysteresis is used to simulate magnetic behavior of the grain oriented silicon strip of ET114-27 type. Determination of B-H hysteretic curve is based on measurement of the initial magnetization curve and the main hysteresis loop. The Preisach distribution function (PDF) of ET114-27 material...
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Hysteresis curves and loops for harmonic and impulse perturbations in some non-equilibrium gases
PublikacjaEvolution of sound in a relaxing gas whose properties vary in the course of wave propagation, is studied. A relaxing medium may reveal normal acoustic properties or be acoustically active. In the first case, losses in acoustic energy lead to an increase in internal energy of a gas similarly as it happens in Newtonian fluids. In the second case, acoustic energy increases in the course of sound propagation, and the internal energy...
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On a flexomagnetic behavior of composite structures
PublikacjaThe popularity of the studies is getting further on the flexomagnetic (FM) response of nano-electro-magneto machines. In spite of this, there are a few incompatibilities with the available FM model. This study indicates that the accessible FM model is inappropriate when considering the converse magnetization effect that demonstrates the necessity and importance of deriving a new FM relation. Additionally, the literature has neglected...
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BEHAVIOUR OF TiO2/CHITOSAN DISPERSION AS A FUNCTION OF SOLUTION pH
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Effect of WC on electroposition and corossion behaviour of chromium coatings
PublikacjaWłaściwości warstw chromowych zawierających różne ilości drobin WC zbadano metodą XPS, EPS oraz XRD. Metody te pozwoliły określić morfologię i skład chemiczny powłok. Właściwości antykorozyjne określono dla różnych czasów ekspozycji próbek w elektrolicie zawierającym 0,01 mol L-1 za pomocą metody woltamperometrycznej oraz spektroskopii impedancyjnej. Badania wykazały, że obecność WC w warstwach chromowych otrzymanych z kąpieli...
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Shortening and non linear load settlement behaviour of piles.
PublikacjaPrzedstawiono praktyczne wartości współczynnika B do obliczeń skrócenia trzonu pali. W analizie zastosowano metodę funkcji transformacyjnych t-z oraz q-z. Wykorzystano wyniki próbnych obciążeń statycznych pali, w sumie 184 pali próbnych.
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Digital measurements of the feedback signals for observing behaviour of a drive.
PublikacjaW pracy omówiono sposoby badań przebiegu ruchu realizowanego przez napęd, w tym poprzez pomiar sygnałów sprzężeń zwrotnych. Przedstawiono różne typy błędów pomiaru sygnałów sprzężeń zwrotnych i ich oddziaływanie na wyniki.
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Thermal imaging in automatic rodent’s social behaviour analysis
PublikacjaLaboratory rodent social behaviour analysis is an extremely important task for biological, medical and pharmacological researches. In this work thermal images features that facilitate analysis are presented. Methods to distinguish objects on the basis of thermal distribution are tested. Actions of grooming or biting one rodent by another - important social behaviour incidents - are clearly visible...
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Influence of grain shape on the mechanical behaviour of granular materials
PublikacjaWe performed series of numerical vertical compression tests on assemblies of 2D granular material using a Discrete Element code and studied the results in regard to the grain shape. The samples consist of 5000 grains made either of 3 overlapping discs (clump - grain with concavities) or of six-edged polygons (convex grain). These two types of grains have a similar external envelope, ruled with a geometrical parameter α. In the...
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Agent-based social network as a simulation of a market behaviour
PublikacjaRecent years and the outbreak of world's economic crisis in 2008 proved the crucial importance of reliable analysis of market dynamics. However, werarely apply models of proper detail level (the global prosperity forecast of 2007 can be seen as a grim proof). The behaviour of individuals and companies is far from being ideal and rational. Many claims that the economic paradigm of rational expectations (coming from J. Muth and R....
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Studying the Behaviour of Pedestrians and Drivers Within Pedestrian Crossings
PublikacjaEvery third road accident in Poland involves a pedestrian as a participant or, most of the time, a casualty. Pedestrian accidents are usually the result of complex situations and the outcome of a number of factors related to driver and pedestrian behaviour and road infrastructure. Safety depends largely on how well the traffic condition is perceived and on visibility in traffic. The re-lations between pedestrians and motorists...
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A two dimensional approach for modelling of pennate muscle behaviour
PublikacjaThe purpose of this study was to elaborate a two-dimensional approach for unipennate and bipennate striated skeletal muscle modelling. Behavior of chosen flat pennate muscle is modelled as a rheological system composed of serially linked passive and active fragments having different mechanical properties. Each fragment is composed of three elements: mass element, elastic element and viscous element. Each active fragment furthermore...
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Behaviour of Fascia-Implant Structure under the Impulse Pressure
PublikacjaW pracy przedstawiono badania eksperymentalne wykonane dla modeli zaoperowanych przepuklin brzusznych poddanych impulsowemu działaniu ciśnienia, analogicznego do kaszlu pooperacyjnego. Zbudowano 57 modeli zgodnie ze sztuką oparacji laparoskopowej, z użyciem powiezi świńskiej, pięciu typów implantów i pięciu rodzajów łączników. Opisano otrzymane wyniki wskazując na mocniejsze i słabsze rozwiązania operacyjne.
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Asymptotic behaviour in the set of nonhomogeneous chains of stochastic operators
PublikacjaWe study different types of asymptotic behaviour in the set of (infinite dimensional) nonhomogeneous chains of stochastic operators acting on L1(μ) spaces. In order to examine its structure we consider different norm and strong operator topologies. To describe the nature of the set of nonhomogeneous chains of Markov operators with a particular limit behaviour we use the category theorem of Baire. We show that the geometric structure...
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Investigating lubricants behaviour in microgravity for vibration damping purposes
PublikacjaVibration is one of the harshest environments an object is exposed to during and after launch into space on a launch vehicle. Such vibrations should be damped to avoid destruction of the spacecraft or its elements. Currently, active and material damping is used. A possibility of using lubrication as the damping factor is suggested by some research. MoS2 is a typical solid lubricant used in space applications. Its properties vary...
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On the broadband behaviour of planar elliptical dipole-modal approach
PublikacjaBroadband behavior of planar elliptical dipole structure is analyzed using Illuminatin Modes (IM) approach. The current on patch has been expanded in series of eigenfunctions in form of Mathieu radial and angular functions. The frequency behavior of current distributions and related powers have been discussed to explain the mechanism of broadband operation of the dipole. Different behavior of radiations patterns in wide frequency...