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Nonlinear impedance of 50Bi2VO5.5-50SrB4O7 fully crystallized glass at 813 K measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrcial properties of 50Bi2VO5.5-50SrB4O7 fully crystallized glass was measured by impedance spectroscopy method.
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Nonlinear impedance of 40Bi2VO5.5-60SrB4O7 annealed glass at 593 K measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrical properties of 40Bi2VO5.5-60SrB4O7 glass annealed at 593 K was measured by impedance spectroscopy method.
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Nonlinear impedance of 50Bi2VO5.5-50SrB4O7 partially crystallized glass at 613 K measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrcial properties of 50Bi2VO5.5-50SrB4O7 partially crystallized glass was measured by impedance spectroscopy method.
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Nonlinear impedance as a function of A.C. voltage for fully crystallized 45Bi2VO5.5-55SrB4O7 glass measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrcial properties as a function of A.C. voltage for fully crystallized 45Bi2VO5.5-55SrB4O7 glass was measured by impedance spectroscopy method.
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Nonlinear impedance of 30Bi2VO5.5-70SrB4O7 fully crystallized glass measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrcial properties of 30Bi2VO5.5-70SrB4O7 fully crystallized glass was measured by impedance spectroscopy method.
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Nonlinear impedance of glass 40Bi2VO5.5-60SrB4O7 annealed at 593 K and next fully crystallized was measured with impedance spectroscopy method at high temperature region
Dane BadawczeThe nonlinear electrcial properties of glass 40Bi2VO5.5-60SrB4O7 annealed at 593 K and next fully crystallized was measured by impedance spectroscopy method.
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Rheological and compressive strength (ultrasonic pulse method) properties of cement pastes containing iron oxide (Fe3O4) nanoparticles
Dane BadawczeRheological data of cement pastes containing different replacement levels of cement with iron oxide nanoparticles deterimined using MCR 301 (Anton Paar) stress-imposed rheometer, equipped with calibrated helicoidal geometry
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Compressible gas density measurement by means of Fourier analysis of interferograms
PublikacjaThis paper describes a method for nonintrusive compressible gas density measurement by means of automated analysis of interferograms using FFT (Fast Fourier Transform), and its implementation using DFT (Discrete Fourier Transform), that does make this measurement technique a fairly valuable and accessible experimental method. The presented approach makes it possible to use the finite fringe setting of the interferometer, thus reducing...
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On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
PublikacjaWe discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present...
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A high-accuracy method of computation of x-ray waves propagation through an optical system consisting of many lenses
PublikacjaThe propagation of X-ray waves through an optical system consisting of many X-ray refractive lenses is considered. Two differential equations are contemplated for solving the problem for electromagnetic wave propagation: first – an equation for the electric field, second – an equation derived for a complex phase of an electric field. Both equations are solved by the use of a finite-difference method. The simulation error is estimated...
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Modeling of free vibrations and resonant frequencies of simply-supported submerged horizontal plate
PublikacjaA theoretical approach was applied to study the vibration of simple-supported submerged horizontal plate. The derived analytical solution was used to determine natural frequencies for a horizontal plate vibrating in fluid. The investigations were conducted for a very wide range of material density and elasticity modulus covering all materials used in engineering practice. Analysis shows that plate vibration frequency decreases...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublikacjaIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...
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RECSYS CHALLENGE 2015: a BUY EVENT PREDICTION IN THE E-COMMERCE DOMAIN
PublikacjaIn this paper we present our approach to RecSys Challenge 2015. Given a set of e-commerce events, the task is to predict whether a user will buy something in the current session and, if yes, which of the item will be bought. We show that the data preparation and enrichment are very important in finding the solution for the challenge and that simple ideas and intuitions could lead to satisfactory results. We also show that simple...
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Estimators of covariance matrices in Msplit(q) estimation
PublikacjaThis paper proposes methods for the determination of covariance matrices of Msplit(q) estimators. The solutions presented here allow Msplit(q) estimation to be supplemented by the operations from the domain of accuracy analysis (especially that concerning estimators of parameters). Theoretical forms of covariance matrices of Msplit(q) estimators were established using the empirical influence functions and the equivalent covariance...
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The correlation of fractal dimension to fracture surface slope for fatigue crack initiation analysis under bending-torsion loading in high-strength steels
PublikacjaIn this study, the fractal dimension of fatigue fracture surfaces is investigated in order to find an alternative failure loading indicator. Some of many metrological factors are generalized by reducing the fracture surface structure to one factor and develop an entire fracture surface procedure by analyzing the impact of surface slope and calculation resolution. Three notched geometries are studied under cyclic bending-torsion:...
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Quantum mechanical which-way experiment with an internal degree of freedom
PublikacjaFor a particle travelling through an interferometer, the trade-off between the available which-way information and the interference visibility provides a lucid manifestation of the quantum mechanical wave-particle duality. Here we analyse this relation for a particle possessing an internal degree of freedom such as spin. We quantify the trade-off with a general inequality that paints an unexpectedly intricate picture of wave-particle...
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Signal propagation in electromagnetic media described by fractional-order models
PublikacjaIn this paper, signal propagation is analysed in electromagnetic media described by fractional-order (FO) models (FOMs). Maxwell’s equations with FO constitutive relations are introduced in the time domain. Then, their phasor representation is derived for one-dimensional case of the plane wave propagation. With the use of the Fourier transformation, the algorithm for simulation of the non-monochromatic wave propagation is introduced....
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Studies of Nonlinear Sound Dynamics in Fluids Based on the Caloric Equation of State
PublikacjaThe sound speed and parameters of nonlinearity B/A, C/A in a fluid are expressed in terms of coefficients in the Taylor series expansion of an excess internal energy, in powers of excess pressure and density. That allows to conclude about features of the sound propagation in fluids, the internal energy of which is known as a function of pressure and density. The sound speed and parameters of nonlinearity in the mixture consisting...
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Source-related Wavefields in Fluids and Dielectrics: A new way of Thinking about Medium Dynamics
PublikacjaAcoustic and electromagnetic wave phenomena may seem to have a proper formal representation in field theory dating from the 19th century, founded on the mathematics of complex functions. This paper shows, however, that when replacing the classical spectrum-domain approach related to the assumption of harmonic timeform of signals, with a time-domain approach imposingnorestrictionastotheclassoftimeevolutionofsourceandfieldsignals,...
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Relations between magnetosonic perturbations as an indicator of a magnetosonic exciter and equilibrium parameters of a plasma
PublikacjaThe thermodynamic relations between perturbation of pressure and pertur- bation of mass density and between components of velocity which specify a magnetosonic wave are theoretically studied. A planar flow with the wave vec- tor forming a constant angle with the equilibrium magnetic field is investigated. The theory considers deviation from the adiabaticity of a flow due to some kind of heating–cooling function and thermal conduction...
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Enhanced Mobility and Large Linear Nonsaturating Magnetoresistance in the Magnetically Ordered States of TmNiC2
PublikacjaWe have studied the magnetic, magnetotransport, and galvanomagnetic properties of TmNiC2. We find that the antiferromagnetic and field induced metamagnetic and ferromagnetic orderings do not suppress the charge density wave. The persistence of Fermi surface pockets, open as a result of imperfect nesting accompanying the Peierls transition, results in an electronic carriers mobility of the order of 4 × 103 cm2 V−1 s−1 in ferromagnetic...
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Optical monitoring of electrochemical processes with ITO-based lossy-mode resonance optical fiber sensor applied as an electrode
PublikacjaIn this work we discuss the application of optical fiber sensors based on lossy-mode resonance (LMR) phenomenon for real-time optical monitoring of electrochemical processes. The sensors were obtained by a reactive high power impulse magnetron sputtering of indium tin oxide (ITO) on a 2.5 cm-long core of polymer-clad silica fibers. The LMR effect made monitoring of changes in optical properties of both ITO and its surrounding medium...
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Features extraction from the electrocatalytic gas sensor responses
PublikacjaOne of the types of gas sensors used for detection and identification of toxic-air pollutant is an electrocatalytic gas sensor. The electrocatalytic sensors are working in cyclic voltammetry mode, enable detection of various gases. Their response are in the form of I-V curves which contain information about the type and the concentration of measured volatile compound. However,...
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Chemical composition of tellurium oxides thin films deposited by magnetron sputtering method
Dane BadawczeThin films were prepared by radio frequency reactive magnetron sputtering technique. Metallic Te target was sputtered for about 45 min in argon-oxygen atmosphere what resulted in 300 nm film thickness deposition. The pressure in the chamber was below 0.2 Pa and substrate was heated at 200 °C. The distance between sputtered target and the Corning 1737...
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XPS analysis of TBBO glass
Dane BadawczeGlasses and glass-ceramics with nominal composition 73 TeO2– 4BaO– 3Bi2O3–18SrF2-2RE2O3 (where RE = Eu, Dy) have been synthesized by conventional melt-quenching technique and subsequent heat treatment at 370 °C for 24 h in air atmosphere. Various Eu3+ to Dy3+ molar ratio have been applied to investigate luminescence properties in both glass and glass-ceramic...
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Data Compression in Ultrasonic Network Communication via Sparse Signal Processing
PublikacjaThis document presents the approach of using compressed sensing in signal encoding and information transferring within a guided wave sensor network, comprised of specially designed frequency steerable acoustic transducers (FSATs). Wave propagation in a damaged plate was simulated using commercial FEM-based software COMSOL. Guided waves were excited by means of FSATs, characterized by the special shape of its electrodes, and modeled...
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GPR investigation of the strengthening system of a historic masonry tower
PublikacjaIn this paper the condition assessment of the strengthening system of a masonry tower was carried out by the GPR method. The study provided unique experimental data acquired during measurements of the reinforced concrete frame embedded in masonry walls. Conducted numerical and experimental investigations were focused on the phenomenon of the diffraction-refraction scattering of the electromagnetic energy. A hyperbola resulting...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublikacjaA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Redukcja obciążeń odmorskich ścian falochronów pionowościennych przy zastosowaniu ścian ażurowych i komór wygaszających
PublikacjaPoszukiwanie optymalnych rozwiązań w projektowaniu falochronów portowo-morskich stanowi ciągłe wyzwanie dla projektantów w dziedzinie hydrotechniki portowo-morskiej. W przypadku falochronów morskich jednym z decydujących czynników mających wpływ na wybór rodzaju konstrukcji jest uzyskanie maksymalnej możliwej redukcji obciążeń od falowania morskiego. Niniejsza praca poświęcona jest rozwiązaniom konstrukcyjnym skrzyń żelbetowych,...
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NARAŻENIA NAPIĘCIOWE SILNIKÓW INDUKCYJNYCH ZASILANYCH Z FALOWNIKÓW NAPIĘCIA
PublikacjaW artykule przedstawiono zagadnienia związane z narażeniami izolacji silników pracujących w układach napędowych z falownikami napięcia. Znaczne stromości napięć oraz zjawiska falowe w przewodach zasilających powodują przyspieszoną degradacje izolacji maszyn. Rozwiązaniem jest stosowanie filtrów biernych na wyjściu falownika.
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Diagnostics of pillars in St. Mary’s Church (Gdańsk, Poland) using the GPR method
PublikacjaThe main goal of this study was non-destructive evaluation of pillars in the St. Mary’s Church (Gdańsk, Poland) using the ground penetrating radar (GPR) technique. The GPR inspection was conducted on four brick masonry pillars and five pillars strengthened by reinforced concrete jacketing. Data were acquired with a 2 GHz antenna along longitudinal and transverse profiles. The study involved the estimation of the electromagnetic...
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Instantaneous Heating and Cooling Caused by Periodic or Aperiodic Sound of Any Characteristic Duration in a Gas with Vibrational Relaxation
PublikacjaThermodynamic relaxation of internal degrees of a molecule's freedom in a gas occurs with some characteristic time. This makes wave processes in a gas behave differently depending on the ratio of characteristic duration of perturbations and the relaxation time. In particular, generation of the secondary non-wave modes by intense sound in a nonlinear flow dependens on frequency. These kinds of interaction are considered in this...
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Ultrasonic spectroscopy of silicon single crystal
PublikacjaSpecimens of Si single crystals with different crystal orientation [100] and [110] were studied by the electro-ultrasonic spectroscopy (EUS) and Resonant Ultrasonic Spectroscopy (RUS). A silicon single crystal is an anisotropic crystal, so its properties are different in different directions in the material relative to the crystal orientation. EUS is based on interaction of two signals: electric AC signal and ultrasonic signal,...
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Damage detection in plates based on Lamb wavefront shape reconstruction
PublikacjaMany of the current studies in the area of damage detection using elastic wave propagation are based on deploying sensor networks with a large number of piezoelectric transducers to detect small-size cracks. A major limitation of these studies is that cracks are usually larger and have different shapes in real cases. Moreover, using a large number of sensing nodes for damage detection is both costly and computationally intensive....
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Application of the Boundary Element Method for the Simulation of Two-dimensional Viscous Incompressible Flow
PublikacjaThe paper presents the application of an indirect variant of the boundary element method (BEM) to solve the two-dimensional steady flow of a Stokes liquid. In the BEM, a system of differential equations is transformed into integral equations. Thi smakes it possible to limit discretization to the border of the solution. Numerical discretization of the computational domain was performed with linear boundary elements, for which a...
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System Loss Model for Body-to-Body Networks in Indoor and Outdoor Environments
PublikacjaA system loss model for body-to-body networks in indoor and outdoor environments is proposed in this paper, based on measurements taken at 2.45 GHz. The influence of the type of environment, antenna visibility and user mobility on model parameters has been investigated. A significant impact of mutual antennas’ placement and their visibility is shown. The proposed model fits well to empirical data, with the average root mean square...
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Comparative analysis of numerical with optical soliton solutions of stochastic Gross–Pitaevskii equation in dispersive media
PublikacjaThis article deals with the stochastic Gross–Pitaevskii equation (SGPE) perturbed with multiplicative time noise. The numerical solutions of the governing model are carried out with the proposed stochastic non-standard finite difference (SNSFD) scheme. The stability of the scheme is proved by using the Von-Neumann criteria and the consistency is shown in the mean square sense. To seek exact solutions, we applied the Sardar subequation...
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On the Existence of Homoclinic Type Solutions of a Class of Inhomogenous Second Order Hamiltonian Systems
PublikacjaWe show the existence of homoclinic type solutions of a class of inhomogenous second order Hamiltonian systems, where a C1-smooth potential satisfies a relaxed superquadratic growth condition, its gradient is bounded in the time variable, and a forcing term is sufficiently small in the space of square integrable functions. The idea of our proof is to approximate the original system by time-periodic ones, with larger and larger...
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Nowy wewnątrzbudynkowy algorytm wyznaczania położenia obiektów
PublikacjaW referacie zaprezentowano nowy wewnątrzbudynkowy algorytm wyznaczania położenia obiektów WAP. W algorytmie tym uwzględnia się właściwości środowiska propagacyjnego, dzięki czemu dokładność estymat położenia obiektów wyznaczonych algorytmem WAP jest większa niż wyznaczonych znanymi algorytmami Chana oraz Foy’a. W referacie przedstawiono wyniki analizy porównawczej tych trzech algorytmów z użyciem rzeczywistych pomiarów odległości...
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Multipoint Ultrasonic Diagnostics System of Prestressed T-Beams
PublikacjaThis paper is devoted to the application of ultrasonic wave propagation phenomena for the diagnostics of prestressed, concrete, bridge T-beams. A multi-point damage detection system is studied with use of numerically obtained data. The system is designed to detect the presence of the material discontinuities as well as their location.
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Alternative convolution approach to friction in unsteady pipe flow
PublikacjaIn the paper some aspects of the unsteady friction in pipe flow expressed by the convolution are analyzed. This additional term introduced into the motion equation involves the accelerations of fluid occurring in the past and a weighting function. The essence of such approach is to assume the appropriate form of weighting function. However, until now no fully reliable formula for this function has been found. To avoid some inconveniences...
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TaRh 2 B 2 and NbRh 2 B 2 : Superconductors with a chiral noncentrosymmetric crystal structure
PublikacjaIt is a fundamental truth in solid compounds that the physical properties follow the symmetry of the crystal structure. Nowhere is the effect of symmetry more pronounced than in the electronic and magnetic properties of materials—even the projection of the bulk crystal symmetry onto different crystal faces is known to have a substantial impact on the surface electronic states. The effect of bulk crystal symmetry on the properties...
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Corrosion damage identification based on the symmetry of propagating wavefield measured by a circular array of piezoelectric transducers: Theoretical, experimental and numerical studies
PublikacjaThe article investigates the results obtained from numerical simulations and experimental tests concerning the propagation of guided waves in corroded steel plates. Developing innovative methodologies for assessing corrosion-induced degradation is crucial for accurately diagnosing offshore and ship structures exposed to harsh environmental conditions. The main aim of the research is to analyze how surface irregularities affect...
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DETERMINATION OF SEAKEEPING PERFORMANCE FOR A CASE STUDY VESSEL BY THE STRIP THEORY METHOD
PublikacjaThe increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the...
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Evaluation of propagation parameters of open guiding structures with the use of complex root finding algorithms
PublikacjaAn efficient complex root tracing algorithm is utilized for the investigation of electromagnetic wave propagation in open guiding structures. The dispersion characteristics of propagated and leaky waves are calculated for a couple of chosen waveguides. The efficiency of the root tracing algorithm is discuses and compared to a global root finding algorithm.
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Estimation of blood pressure parameters using ex-Gaussian model
PublikacjaThe paper presents an example of model-based estimation of blood pressure parameters (onset, systolic and diastolic pressure) from continuous measurements. First, the signal was low pass filtered and its quality was estimated. Good quality periods were divided into beats using an electrocardiogram. Next, the beginning of each beat of the blood pressure signal was approximated basing on the function created from the sum of two independent...
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Synthesis and characterization of mononuclear Zn(II), Co(II) and Ni(II) complexes containing a sterically demanding silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol
PublikacjaFour heteroleptic complexes of zinc(II), cobalt(II) and nickel(II) containing a monodentate silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol (TDST), were prepared and characterized. The geometries of ligands in the complexes are typical: distorted tetrahedral in zinc and cobalt(II) complexes and square planar in nickel(II) compound. Magnetic studies performed for Ni(II) and Co(II) compounds confirm the...
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Self-Testing of Analog Parts Terminated by ADCs Based on Multiple Sampling of Time Responses
PublikacjaA new approach for self-testing of analog parts terminated by analog-to-digital converters in mixed-signal electronic microsystems controlled by microcontrollers is presented. It is based upon a new fault diagnosis method using a transformation of the set of voltage samples of the time response of a tested analog part to a square impulse into localization curves placed in a multidimensional measurement space. The method can be used...
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On the Possibility of Increasing Ship Energy Efficiency Through Improved Propulsion Control System
PublikacjaThis paper summarizes the analyses conducted to assess the impact of the ship's propulsion control system on energy efficiency in calm, manoeuvre, and sea wave conditions, where the goal of the investigation is to develop new strategies for controlling the ship's motion while considering the interactions between the hull, engine, and propeller.
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Design and Experiments of a Piezoelectric Motor Using Three Rotating Mode Actuators
PublikacjaThis paper represents a numerical and experimental investigation of the multicell piezoelectric motor. The proposed design consists of three individual cells that are integrated into the stator, double rotor, and a preload system combined into a symmetrical structure of the motor. Each of the cells is characterized by a traveling wave and rotating mode motor. A finite element numerical analysis is carried out to obtain optimal...