Search results for: EQUIVALENT ELECTRIC CIRCUIT METHOD
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Broken rotor bar impact on sensorless control of induction machine
PublicationThe aim of the research is analysis of the sensorless control system of induction machine with broken rotor for diagnostic purposes. Increasing popularity of sensorless controlled variable speed drives requires research in area of reliability, range of stable operation, fault symptoms and application of diagnosis methods. T transformation (Cunha et al.,2003) used for conversion of instantaneous rotor currents electrical circuit...
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Self-compacting grout to produce two-stage concrete
PublicationTraditional concrete (TC) is primarily composed...
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Multi-fidelity robust aerodynamic design optimization under mixed uncertainty
PublicationThe objective of this paper is to present a robust optimization algorithm for computationally efficient airfoil design under mixed (inherent and epistemic) uncertainty using a multi-fidelity approach. This algorithm exploits stochastic expansions derived from the Non-Intrusive Polynomial Chaos (NIPC) technique to create surrogate models utilized in the optimization process. A combined NIPC expansion approach is used, where both...
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TINKTEP: A fully self-consistent, mutually polarizable QM/MM approach based on the AMOEBA force field
PublicationWe present a novel quantum mechanical/molecular mechanics (QM/MM) approach in which a quantum subsystem is coupled to a classical subsystem described by the AMOEBA polarizable force field. Our approach permits mutual polarization between the QM and MM subsystems, effected through multipolar electrostatics. Self-consistency is achieved for both the QM and MM subsystems through a total energy minimization scheme. We provide an expression...
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Preparation and characterization of dummy-template molecularly imprinted polymers as potential sorbents for the recognition of selected polybrominated diphenyl ethers
PublicationThe main aim of this work was to conduct the preliminary/basic research concerning the preparation process of a new dummy molecularly imprinted polymer (DMIP) materials. Developed DMIPs were proposed as a sorption material in solid-phase extraction (SPE) technique for recognition of selected low mass polybrominated diphenyl ethers (PBDEs) e PBDE-47 and PBDE-99. Four new DMIPs were synthesized employing bulky polymerization technique...
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Air trapping problem during infiltration on the large areas
PublicationThe process of flow modeling in unsaturated porous medium is often found in many fields of sciences: geology, fluid mechanics, thermodynamics, microbiology or chemistry. Problem is relatively complicated due to complexity of the system which contains three phases: water, air and soil skeleton. The flow of water in such a medium can be described using two-phase (2PH) flow formulation, which accounts the inflow of air and water phases,...
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Lanthanide ions (Eu3+, Er3+, Pr3+) as luminescence and charge carrier centers in Sr2TiO4
PublicationA series of strontium orthotitanate (Sr2TiO4) samples doped with 2% of a mole of europium, praseodymium, and erbium were obtained using the solid-state synthesis method. The X-ray diffraction (XRD) technique confirms the phase purity of all samples and the lack of the influence of dopants at a given concentration on the structure of materials. The optical properties indicate, in the case of Sr2TiO4:Eu3+, two independent emission...
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Characterization and Filtration Efficiency of Sustainable PLA Fibers Obtained via a Hybrid 3D-Printed/Electrospinning Technique
PublicationThe enormous world demand for personal protective equipment to face the current SARS-CoV-2 epidemic has revealed two main weaknesses. On one hand, centralized production led to an initial shortage of respirators; on the other hand, the world demand for single-use equipment has had a direct and inevitable effect on the environment. Polylactide (PLA) is a biodegradable, biocompatible, and renewable thermoplastic polyester, mainly...
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Monomeric Triphosphinoboranes: Intramolecular Lewis Acid–Base Interactions between Boron and Phosphorus Atoms
PublicationHerein, we present the synthesis of the first fully characterized monomeric triphosphinoboranes. The simple reaction of boron tribromide with three equivalents of bulky lithium phosphide tBu2PLi yielded triphosphinoborane (tBu2P)3B. Triphosphinoboranes with diversified phosphanyl substituents were obtained via a two-step reaction, in which isolable bromodiphosphinoborane (tBu2P)2BBr is first formed and then reacts with one equivalent...
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The loop impedance measurement
Open Research DataThe loop impedance measurement
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Wavelet transform-based approach to defect identification in railway carbon contact strips.
PublicationPantographs of electric rail vehicles are fitted with carbon contact strips, which slide along the contact wire of catenary to provide constant electrical contact. Contact strips are exposed to wear and damages. Using damaged contact strips significantly increases the risk of catenary rupture. Therefore, their technical condition has to be inspected frequently. In previous work a 3D laser scanning system was proposed for recording...
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Electrochemical synthesis of 2D copper coordination-polymers: Layer-stacking deviation induced by the solvent and its effect on the adsorptive properties
PublicationA 2D Cu-based Metal-Organic Framework (MOF), namely copper-terephthalate (Cu(1,4-BDC)), was successfully synthesized by electrochemical method for effective methylene blue (MB) sorption from aqueous solutions. The composition, morphology, and the presence of functional groups in the obtained material were verified by Fourier Transform Infrared spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD), Thermal (TGA), and Elemental (EA)...
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Modeling of Electrified Transportation Systems Featuring Multiple Vehicles and Complex Power Supply Layout
PublicationThe paper proposes a novel approach to modeling electrified transportation systems. The proposed solution reflects the mechanical dynamics of vehicles as well as the distribution and losses of electric supply. Moreover, energy conversion losses between the mechanical and electrical subsystems and their bilateral influences are included. Such a complete model makes it possible to replicate, e.g., the impact of voltage drops on vehicle...
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Ce site dilution effects in the antiferromagnetic heavy fermion CeIn3
PublicationLa-doped intermetallic single crystals of Ce1−xLaxIn3 were synthesized via an In self-flux method throughout the entire range (x = 0–1). The prototypical heavy-fermion compound CeIn3 shows an antiferromagnetic phase transition at 10.1 K and becomes superconducting near a critical pressure where TN is completely suppressed. As the La concentration increases, Ce moments are diluted, and the lattice constant increases linearly, satisfying Vegard’s...
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Lighting conditions in Home Office and occupant’s perception: an international study
PublicationThe global pandemic and physical distancing restrictions are forcing us to rethink how residential buildings are used regarding the visual environment. This paper describes home office lighting conditions within different countries and continents. The aim is to define the current limitations of home offices in providing a resilient visual environment. The work was developed by a team of international experts working together on...
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Electronic States of Tris(bipyridine) Ruthenium(II) Complexes in Neat Solid Films Investigated by Electroabsorption Spectroscopy
PublicationWe present the electric field-induced absorption (electroabsorption, EA) spectra of the solid neat films of tris(bipyridine) Ru(II) complexes, which were recently functionalized in our group as photosensitizers in dye-sensitized solar cells, and we compare them with the results obtained for an archetypal [Ru(bpy)3]2+ ion (RBY). We argue that it is difficult to establish a unique set of molecular parameter values by discrete parametrization...
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Real-time hybrid model of a wind turbine with doubly fed induction generator
PublicationIn recent years renewable sources have been dominating power system. The share of wind power in energy production increases year by year, which meets the need to protect the environment. Possibility of conducting, not only computer simulation, but also laboratory studies of wind turbine operation and impact on the power system and other power devices in laboratory conditions would be very useful. This article presents a method...
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Innovative method of localization airplanes in VCS (VCS-MLAT) distributed system
PublicationThe article presents the concept and the structure of the localization module. The prototype module is the part of the VCS (VCS-MLAT) localization distributed system. The device receives the audio signal transmitted in airplanes band (118 MHz – 136 MHz). Received data with the timestamps are send to the main server. The data from multiple devices estimates the localization of the airplane. The main aim of the project is the analysis...
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Surrogate modeling of impedance matching transformers by means of variable‐fidelity electromagnetic simulations and nested cokriging
PublicationAccurate performance evaluation of microwave components can be carried out using full‐wave electromagnetic (EM) simulation tools, routinely employed for circuit verification but also in the design process itself. Unfortunately, the computational cost of EM‐driven design may be high. This is especially pertinent to tasks entailing considerable number of simulations (eg, parametric optimization, statistical analysis). A possible...
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Continuation classes for a two-patch vaccination model
Open Research DataThis dataset contains selected results of rigorous numerical computations described in Section 5 of the paper "Rich bifurcation structure in a two-patch vaccination model" by D.H. Knipl, P. Pilarczyk, G. Röst, published in SIAM Journal on Applied Dynamical Systems (SIADS), Vol. 14, No. 2 (2015), pp. 980–1017, doi: 10.1137/140993934.
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Subarachnoid Space: New Tricks by an Old Dog
PublicationPurpose: The purpose of the study was to: (1) evaluate the subarachnoid space (SAS) width and pial artery pulsation in both hemispheres, and (2) directly compare magnetic resonance imaging (MRI) to near-infrared transillumination/backscattering sounding (NIR-T/BSS) measurements of SAS width changes in healthy volunteers.Methods: The study was performed on three separate groups of volunteers, consisting in total of 62 subjects (33...
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Natural convection in symmetrically heated vertical channels
PublicationThe study describes natural convection through a vertical channel, open on four sides and bound by two isothermal walls. Both balancing and infrared experimental investigations were performed in air (Pr = 0.71) to estimate the impact of channel width s and wall-to-ambient temperature difference (tw - t∞) on natural convective heat transfer, the formation of air flow patterns and the rate of flow pattern formation. The study was...
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INFLUENCE OF TEST CONDITIONS ON TYRE/ROAD NOISE MEASURED BY THE DRUM METHOD
PublicationTyre/road noise is one of the most important environmental problems related to road traffic. Nowadays a few standard procedures of tyre/road noise measurements are in use. Unfortunately, measurement conditions specified within relevant standards are very different. For example, procedure described in ISO 11819-2 used for pavement investigations requires tyre load of 3200 N and capped inflation pressure of 200 kPa. At the same time...
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Material Design and Optimisation of Electrochemical Li-Ion Storage Properties of Ternary Silicon Oxycarbide/Graphite/Tin Nanocomposites
PublicationIn this work, we present the characterization and electrochemical performance of various ternary silicon oxycarbide/graphite/tin (SiOC/C/Sn) nanocomposites as anodes for lithium-ion batteries. In binary SiOC/Sn composites, tin nanoparticles may be produced in situ via carbothermal reduction of SnO2 to metallic Sn, which consumes free carbon from the SiOC ceramic phase, thereby limiting the carbon content in the final ceramic nanocomposite....
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Computationally efficient two-objective optimization of compact microwave couplers through corrected domain patching
PublicationFinding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective...
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Machine-Learning-Based Global Optimization of Microwave Passives with Variable-Fidelity EM Models and Response Features
PublicationMaximizing microwave passive component performance demands precise parameter tuning, particularly as modern circuits grow increasingly intricate. Yet, achieving this often requires a comprehensive approach due to their complex geometries and miniaturized structures. However, the computational burden of optimizing these components via full-wave electromagnetic (EM) simulations is substantial. EM analysis remains crucial for circuit...
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Low-Cost Yield-Driven Design of Antenna Structures Using Response-Variability Essential Directions and Parameter Space Reduction
PublicationQuantifying the effects of fabrication tolerances and uncertainties of other types is fundamental to improve antenna design immunity to limited accuracy of manufacturing procedures and technological spread of material parameters. This is of paramount importance especially for antenna design in the industrial context. Degradation of electrical and field properties due to geometry parameter deviations often manifests itself as, e.g.,...
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Justifying the prolongation of the service life of the bearing structure of a tank car when using Y25 bogies
PublicationThis paper substantiates the use of Y25 bogies under tank cars in order to prolong their service life. The reported study has been carried out for a tank car with rated parameters, as well as the actual ones, registered during full-scale research. Mathematical modeling was performed to determine the basic indicators of the tank car dynamics. The differential equations of motion were solved by a Runge-Kutta method using the Mathcad...
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Studies of the Modelling Accuracy of Steam Turbine Control Systems for Diagnostic Tests of Automatic Synchronizers
PublicationOne of the important factors that affect the reliable operation of the power system and the rapid restitution after disaster is a quick and effective combining synchronous electric power facilities to operate in parallel. Hence, diagnostics of automatic synchronizers at every stage of their life, from building a prototype, through the whole life, until removing such devices from the operation, is an extremely important and responsible...
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Wire Arc Additive Manufactured Mild Steel and Austenitic Stainless Steel Components: Microstructure, Mechanical Properties and Residual Stresses
PublicationWire arc additive manufacturing (WAAM) is an additive manufacturing process based on the arc welding process in which wire is melted by an electric arc and deposited layer by layer. Due to the cost and rate benefits over powder-based additive manufacturing technologies and other alternative heat sources such as laser and electron beams, the process is currently receiving much attention in the industrial production sector. The gas...
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Minimizing Greenhouse Gas Emissions From Ships Using a Pareto Multi-Objective Optimization Approach
PublicationTo confront climate change, decarbonization strategies must change the global economy. According to statements made as part of the European Green Deal, maritime transport should also become drastically less polluting. As a result, the price of transport must reflect the impact it has on the environment and on health. In such a framework, the purpose of this paper is to suggest a novel method for minimizing emissions...
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Modelowanie matematyczne górnej sieci trakcyjnej dla potrzeb diagnostyki odbieraków prądu
PublicationGórna sieć trakcyjna jest obecnie najbardziej skutecznym sposobem zasilania kolejowych pojazdów elektrycznych. Wzrost prędkości pojazdów zwiększa pobór mocy i wymaga zapewnienia właściwej współpracy odbieraków prądu pojazdów z siecią jezdną. Metody modelowania i projektowania wspomaganego komputerowo dla górnej sieci trakcyjnej są obecnie na całym świecie szeroko rozwijane. W artykule przedstawiono nowy model matematyczny elementów...
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Improved RSS-Based DoA Estimation Accuracy in Low-Profile ESPAR Antenna Using SVM Approach
PublicationIn this paper, we have shown how the overall performance of direction-of-arrival (DoA) estimation using lowprofile electronically steerable parasitic array radiator (ESPAR) antenna, which has been proposed for Internet of Things (IoT) applications, can significantly be improved when support vector machine (SVM) approach is applied. Because the SVM-based DoA estimation method used herein relies solely...
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On mechanics of piezocomposite shell structures
PublicationThis study presents an original and novel investigation into the mechanics of piezo-flexo-magneto-elastic nanocomposite doubly-curved shells (PFMDCSs) and the ability to detect the lower and higher levels of electro-magnetic fields. In this context, by utilizing the first-order shear deformation shell model, stresses and strains are acquired. By imposing Hamilton's principle and the von Kármán approach, the governing equations...
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Deep learning for ultra-fast and high precision screening of energy materials
PublicationSemiconductor materials for energy storage are the core and foundation of modern information society and play important roles in photovoltaic system, integrated circuit, spacecraft technology, lighting applications, and other fields. Unfortunately, due to the long experiment period and high calculation cost, the high-precision band gap (the basic characteristic parameter) of semiconductor is difficult to obtain, which hinders the...
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Solubility of Methane in Water: Some Useful Results for Hydrate Nucleation
PublicationIn this paper, the solubility of methane in water along the 400 bar isobar is determined by computer simulations using the TIP4P/Ice force field for water and a simple LJ model for methane. In particular, the solubility of methane in water when in contact with the gas phase and the solubility of methane in water when in contact with the hydrate has been determined. The solubility of methane in a gas–liquid system decreases as temperature...
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Strength analysis of a large-size supporting structure for an offshore wind turbine
PublicationThe offshore wind power industry is the branch of electric energy production from renewable sources which is most intensively developed in EU countries. At present, there is a tendency to install larger-power wind turbines at larger distances from the seashore, on relatively deep waters. Consequently, technological solutions for new supporting structures intended for deeper water regions are undergoing rapid development now. Various...
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Finite-difference time-domain analyses of active cloaking for electrically-large objects
PublicationInvisibility cloaking devices constitute a unique and potentially disruptive technology, but only if they can work over broad bandwidths for electrically-large objects. So far, the only known scheme that allows for broadband scattering cancellation from an electrically-large object is based on an active implementation where electric and magnetic sources are deployed over a surface surrounding the object, but whose ‘switching on’...
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Inception and Propagation of Electrical Trees in the Presence of Space Charge in HVAC Extruded Cables
PublicationThis paper presents the space charge impact on the inception and propagation of electrical trees in cross-linked polyethylene (XLPE) insulation via simulations and experimentation. A 3D finite element analysis (FEA)-based modeling is proposed to simulate electrical trees via a needle embedded on the XLPE insulation. The proposed FEA model demonstrates the influence of the space charge magnitude and polarity on the initiation of...
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Numerical simulation of cold flow and combustion in a swirl stabilized combustor
PublicationA numerical simulation model was developed to investigate the cold flow and combustion using Ansys FLUENT 2021R1. The governing equations were solved using the pressure-based method, and pressure–velocity coupling was performed using the SIMPLE method. To model the turbulent process, the RSM model was used. Non-premixed model is chosen to solve the chemical kinetics between fuel and oxigen. Radiation heat transfer was calculated...
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A review on analytical models of brushless permanent magnet machines
PublicationThis 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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Low-Cost Quasi-Global Optimization of Expensive Electromagnetic Simulation Models by Inverse Surrogates and Response Features
PublicationConceptual design of contemporary high-frequency structures is typically followed by a careful tuning of their parameters, predominantly the geometry ones. The process aims at improving the relevant performance figures, and may be quite expensive. The reason is that conventional design methods, e.g., based on analytical or equivalent network models, often only yield rough initial designs. This is especially the case for miniaturized...
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Continuation classes for a population model with harvesting. Case He-S1: Equal harvesting of juveniles and adults, survival rates of juveniles and adults add up to 1
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Continuation classes for a population model with harvesting. Case Ha-S1: Harvesting adults only, survival rates of juveniles and adults add up to 1
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Continuation classes for a population model with harvesting. Case He-Se: Equal harvesting and equal survival rates of juveniles and adults
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Continuation classes for a population model with harvesting. Case Hj-S1: Harvesting juveniles only, survival rates of juveniles and adults add up to 1
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Continuation classes for a population model with harvesting. Case Hj-Se: Harvesting juveniles only, equal survival rates of juveniles and adults
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Continuation classes for a population model with harvesting. Case Ha-Se: Harvesting adults only, equal survival rates of juveniles and adults
Open Research DataThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper "Global dynamics in a stage-structured discrete population model with harvesting" by E. Liz and P. Pilarczyk: Journal of Theoretical Biology, Vol. 297 (2012), pp. 148–165, doi: 10.1016/j.jtbi.2011.12.012.
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Nonlinear impedance of as-quenched Bi2VO5.5 glass-ceramic was measured with impedance spectroscopy method at low temperature region
Open Research DataThe nonlinear electrical properties of as-quenched Bi2VO5.5 glass-ceramic was measured by impedance spectroscopy method.
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Synteza bezczujnikowego sterowania maszyną indukcyjną klatkową zasilaną z falownika prądu
PublicationSynteza bezczujnikowego sterowania maszyną indukcyjną klatkową zasilaną z falownika prądu stanowi cel niniejszej monografii. Praca zawiera podstawowe informacje na temat modelowania układu napędowego z maszyną indukcyjną klatkową zasilaną z falownika prądu. Przedstawiono informacje na temat linearyzacji nieliniowych obiektów. Na pod-stawie metody syntezy strukturalnej opracowano nowe transformacje do postaci zmien-nych multiskalarnych,...