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Mathematical Models in Design Process of Ship Bow Thrusters
PublikacjaThe presentation is about an application of simulation models for computer-aided design of ship bow thrusters. Generation of simulation models of ship bow thruster requires development and verifying of mathematical models of system component elements. Using the results of simulation the expert system is able to determine, that the rules of classification societies are met. Design procedures and mathematical models are part of an...
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Catena-Poly[[(tetrahydrofuran-[kappa]O)lithium(I)]-bis([mu]-trimethylsilanolato-[kappa]2O:O)-gallium(III)-bis([mu]-trimethylsilanolato-[kappa]2O:O)-[(tetrahydrofuran-[kappa]O)lithium(I)]-[mu]-bromido]
PublikacjaThe title chain polymer compound, [GaLi2Br(C3H9OSi)4(C4H8O)2]n, was obtained in the reaction of GaBr3 with Me3SiOLi in toluene/tetrahydrofuran. The GaIII atom, located on a twofold rotation axis, is coordinated by four trimethylsilanolate ligands and has a distorted tetrahedral geometry. The LiI atom is four coordinated by one bridging Br atom located on an inversion centre, two trimethylsilanolate ligands and one tetrahydrofurane...
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Rotational Design Space Reduction for Cost-Efficient Multi-Objective Antenna Optimization
PublikacjaCost-efficient multi-objective design of antenna structures is presented. Our approach is based on design space reduction algorithm using auxiliary single-objective optimization runs and coordinate system rotation. The initial set of Pareto-optimal solutions is obtained by optimizing a response surface approximation model established in the reduced space using coarse-discretization EM simulation data. The optimization engine is...
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Design and modeling of the piezoelectric motor based on three resonance actuators
PublikacjaThis paper describes a piezoelectric motor which combines advantages from two existing piezoelectric motors topologies. The research work presents the design, simulations and measurements of the piezoelectric motor with three rotation-mode actuators. The aim of the project was to obtain the high speed piezoelectric motor. Other advantages of this conception are blocking torque, short response times, the ability to work in a hostile...
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CORROSION TESTING OF SAMPLES ACCORDING TO ASTM G36
PublikacjaAt the end of the study, samples were found to have structures characteristic for intercrystalline corrosion. This indicates that the samples provided (fragments of the whole) were sensitized before starting the study in boiling MgCl2.On cross sections, fine cracks are observed on all samples tested.
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Evaluation of Path Based Methods for Conceptual Representation of the Text
PublikacjaTypical text clustering methods use the bag of words (BoW) representation to describe content of documents. However, this method is known to have several limitations. Employing Wikipedia as the lexical knowledge base has shown an improvement of the text representation for data-mining purposes. Promising extensions of that trend employ hierarchical organization of Wikipedia category system. In this paper we propose three path-based...
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Transition curve with smoothed curvature at its ends for railway roads
PublikacjaIn the paper, in view of a railway ballasted track, a new concept of transition curve of linear form of curvature along its length and smoothed extreme regions is presented. For this purpose use has been made of an original, universal method for identifying transition curves by means of differential equations. Some general curvature equations for three regions investigated have been determined to be followed by appropriate parametric...
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Surface active fatty acid ILs: Influence of the hydrophobic tail and/or theimidazolium hydroxyl functionalization on aggregates formation
PublikacjaNine structurally-related fatty acid ionic liquids have been prepared and their thermal behavior as well as their ability to self-assemble in water has been investigated. The thermal properties were studied by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), while the aggregation behavior was analyzed by tensiometry, isothermal titration calorimetry (ITC), conductometry, dynamic light scattering (DLS),...
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Application of lightweight cement composite with foamed glass aggregate in shell structures
PublikacjaThe purpose of the paper is to investigate the abilities of applying Granulated Expanded Glass Aggregate (GEGA) as a natural volume substitute of aggregate as a component of lightweight concrete. The GEGA aggregates used in the experiments were made of confused glass waste. In order to achieve satisfactory strength of concrete Granulated Ash Aggregate (GAA) was added as well. To produce specimens three grain sizes of aggregates...
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CHARACTERIZATION STUDY ON MECHANICAL PROPERTIES OF POLYESTER COATED FABRIC
PublikacjaThe scope of the paper is to determine the mechanical properties of the Precontraint 1302 polyester coated fabric under uniaxial and biaxial tensile tests. The results are compared for Precontraint 1302 fabric and other types of coated fabrics. The author applied an orthotropic model and a dense net model to reflect the polyester coated fabric performance under uniaxial and biaxial tensile tests. Material parameters are specified...
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Ocena systemów uziemień z wykorzystaniem pomiarów metodą udarową
PublikacjaW artykule zostały omówione procedury i wymagania stawiane systemom uziemień przez przepisy normalizacyjne z punktu widzenia ich skuteczności w systemie ochrony odgromowej. Podstawą tak sformułowanej oceny są pomiary z zastosowaniem metody udarowej. Metoda taka okazuje się bardzo przydatna zwłaszcza w przypadku uziemień rozległych, jakie pojawiają się we współczesnych obiektach wskutek połączenia różnych elementów uziemiających...
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Analiza numeryczna wpływu długości zakotwienia pręta na zachowanie przyczepności w teście pull-out
PublikacjaW artykule przedstawiono symulacje numeryczne testu pull-out w programie ABAQUS. Symulacje miały na celu ocenienie wpływu długości zakotwienia pręta żebrowanego na przyczepność w tym teście, opierając się na wynikach przeprowadzonych eksperymentów. Interakcję pręta z betonem odwzorowano za pomocą kohezyjnej powierzchni kontaktu, wykorzystując skalibrowane krzywe przyczepność-poślizg, otrzymane z doświadczeń wykonanych w ramach...
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Unusual streaming in chemically reacting gases
PublikacjaNonlinear stimulation of the vorticity mode caused by losses in the momentum of sound in the chemically reacting gas, is considered. The instantaneous dynamic equation which describes the nonlinear generation of the vorticity mode, is derived. It includes a quadratic nonlinear acoustic source. Both periodic and aperiodic sound may be considered as the origin of the vorticity flow. In the non-equilibrium regime of the chemical reaction,...
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Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
PublikacjaA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of...
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Nonlinear Model of Synchronous Generator for Autonomous Electrical Power Systems Analysis
PublikacjaThis paper presents the nonlinear lookup table model for synchronous generator (SG) analysis. The saturation effects of the SG magnetic circuit have been considered. The saturated characteristic of the SG magnetic circuit are based on the open circuit saturation curve for magnetizing inductances. The model has been implemented into the Synopsys/Saber software using the MAST modelling language. To implement the no-load voltage characteristic...
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Rapid design closure of linear microstrip antenna array apertures using response features
PublikacjaA simple yet reliable approach to a rapid design closure of linear antenna array apertures at the electromagnetic (EM)-simulation level is proposed. Our methodology exploits an underlying array factor (AF) model suitably corrected by means of characteristic points (angles and levels) of the radiation pattern of the EM model of the antenna array aperture. This conveniently allows for controlling both the side lobe levels...
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Some kind of joints in composite polymer bridges
PublikacjaContemporary, polymer composites bridge structures are of two types: truss or arch structures(with many joints along the length) and beam structures with limited number of joints. Both of them have special types of composite polymer decks. An ideal solution is to join advantages of two types of structuresdescribed below and create long span FRP beam bridge structure system using joints along the length. Theproblem is to find the...
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Guided wave propagation for assessment of adhesive bonding between steel and concrete
PublikacjaAdhesive bonding is becoming more increasingly important in joining of structural elements. In civil engineering, there is a growing interest in connection by adhesive bonding in steel-concrete flexural members. This study concerns the guided wave propagation technique applied to condition assessment of an adhesive connection between a steel member and a concrete beam. Various states of degradation were considered by producing...
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Electrohydrodynamic Flow Patterns in a Narrow Electrostatic Precipitator with Longitudinal Wire Electrode for Various Electrode Geometries
PublikacjaRecently narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application in diesel engines. In this paper results of 2-dimensional (2D) Particle Image Velocimetry (PIV) measurements of the flow patterns in a narrow ESP for a various electrode geometries are presented. The PIV measurements were carried out in the observation plane that is perpendicular to the ESP duct. The ESP was...
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Conversion of waste biomass to designed and tailored activated chars with valuable properties for adsorption and electrochemical applications
PublikacjaWaste biomass, a renewable energy source, is inexpensive material that has great potential in sorp-tion and electrochemical application. The selected waste materials (corncobs, coconut shells, wal-nuts, and pistachio husks) allow to close the production cycle and enable material recycling, which are important aspects in the hierarchy of waste management. The proposed methodology for pro-duction and activation of biochars can be...
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Facial features extraction for color, frontal images
PublikacjaThe problem of facial characteristic features extraction is discussed. Several methods of features extraction for color en--face photographs are discussed. The methods are based mainly on the colors features related to the specific regions of the human face. The usefulness of presented methods was tested on a database of en--face photographs consisting of 100 photographs.
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Process zone in the Single Cantilever Beam under transverse loading. - Part I: Theoretical analysis
PublikacjaSingle Cantilever Beam (SCB) specimen loaded with a transverse force parallel to the crack front is proposed for the analysis of crack propagation phenomena under mixed mode conditions. The stress redistribution in the adhesive layer in the vicinity of the crack front so as the beam deformation are estimated using a Timoshenko beam on elastic foundation model. This model emphasizes the Mode II contribution due to flexural beam...
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Effects of Micro-Arc Oxidation Process Parameters on Characteristics of Calcium-Phosphate Containing Oxide Layers on the Selective Laser Melted Ti13Zr13Nb Alloy
PublikacjaTitania-based films on selective laser melted Ti13Zr13Nb have been formed by micro-arc oxidation (MAO) at different process parameters (voltage, current, processing time) in order to evaluate the impact of MAO process parameters in calcium and phosphate (Ca + P) containing electrolyte on surface characteristic, early-stage bioactivity, nanomechanical properties, and adhesion between the oxide coatings and substrate. The surface...
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Application of electrochemical impedance spectroscopy to monitoring discharging process of nickel/metal hydride battery.
PublikacjaThis paper presents the possibility of applying impedance analysis to cell diagnostics. In order to obtain characteristic curves of both electrodes of a NiMH battery simultaneously, a reference electrode was added into the circuit. The authors analysed the cell under three cases, i.e. when its properties are determined only by the state of the positive electrode, only by the state of the negative electrode, or when both electrodes...
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Stability analysis of interconnected discrete-time fractional-order LTI state-space systems
PublikacjaIn this paper, a stability analysis of interconnected discrete-time fractional-order (FO) linear time-invariant (LTI) state-space systems is presented. A new system is formed by interconnecting given FO systems using cascade, feedback, parallel interconnections. The stability requirement for such a system is that all zeros of a non-polynomial characteristic equation must be within the unit circle on the complex z-plane. The obtained...
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Ground anchors diagnostic process based on elastic wave propagation method
PublikacjaThe paper is focused on analysis of elastic wave propagation in the context of diagnostics of ground anchors. Numerical simulations were performed to assess the possibility of evaluation of the anchorage quality. It was assumed that the quality and the load capacity of the anchor system directly depend on the length, on which mortar and steel cooperate.
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Analysis of a caustic formed by a spherical reflector: Impact of a caustic on architectural acoustics
PublikacjaFocusing sound in rooms intended for listening to music or speech is an acoustic defect. Design recommendations provide remedial steps to effectively prevent this. However, there is a category of objects of high historical or architectural value in which the sound focus correction is limited or even abandoned. This also applies to indoor or outdoor concert shells, installations for teaching and acoustic presentations, etc. The...
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Multipath Complex Root Tracing
PublikacjaThe problem of multipath root tracing is being addressed in this communication. The self-adaptive complex root tracing algorithm, which was previously utilized for the investigation of various propagation and radiation problems, is analyzed here for the cases when the traced characteristic bifurcates. A procedure of multiroute detection is proposed and demonstrated on the coaxially loaded cylindrical waveguide example.
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Unusual behavior of secondary amine group as a leaving group
PublikacjaIn our recent project we focused on reactivity of2,2-dimethyl-4,6-dioxane-1,3-dione carbamoilo- and thiocarbamoylo- derivatives as a ketenesource. Meldrum`s acid derivatives after thermal decomposition gives substituted keteneswith stoichiometric yield, that can be trapped with various spectrum of nucleophiles likealcohols, thiols, amine, imines etc. In case of5-[3-(dimethylamino)-sulfanyl-propyliden]-2,2-dimethyl-1,3-dioxane-4,6-dione...
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Verification of punching shear outside the shear cap by the direct method
PublikacjaThe proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear...
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Accelerated large scale test set-up design in natural corrosion marine environment
PublikacjaThe standards for conducting small-scale specimen tests are well developed, but there is a lack of direct guidelines for conducting corrosion tests for large-scale specimens. The objective here is to develop a methodology which may be used in designing an accelerated corrosion test of large-scale structural components subjected to a natural corrosion marine environment. Different factors influencing corrosion degradation of steel...
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Zastosowanie nowatorskich materiałów geosyntetycznych w konstrukcjach oporowych z gruntu zbrojonego
PublikacjaArtykuł prezentuje metodę projektowania stromych skarp wznoszonych z gruntów słabo przepuszczalnych, zbrojonych geosiatkami drenującymi. Z analiz przeprowadzonych dla różnej wodoprzepuszczalności gruntu i różnej geometrii skarpy wynika, że pionowy rozstaw i długość zbrojenia mają istotne znaczenie dla stateczności skarpy. Dla gruntów słabo przepuszczalnych, o typowych wartościach współczynników ściśliwości objętościowej oraz konsolidacji,...
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On the Limiting Distribution of Lempel-Ziv’78 Redundancy for Memoryless Sources
PublikacjaWe study the Lempel-Ziv'78 algorithm and show that its (normalized) redundancy rate tends to a Gaussian distribution for memoryless sources. We accomplish it by extending findings from our 1995 paper, in particular, by presenting a new simplified proof of the central limit theorem (CLT) for the number of phrases in the LZ'78 algorithm. We first analyze the asymptotic behavior of the total path length in the associated digital search...
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Evaluation of Gas Chromatography Stationary Phases Based on Morpholinium Ionic Liquids by McReynolds Constants and Activity Coefficients at Infinite Dilution
PublikacjaIn this work, four ionic liquids (ILs) based on the N-alkyl-N-methylmorpholinium cation ([Mor1,R], in which R = 2, 4, 8, or 10) and bis (trifluoromethanesulfonyl)imide anion were synthesized. Using GLC, a number of parameters describing the sorption properties of the investigated ILs were determined. The values of Kovats indices, McReynolds constants, and activity coefficients at infinite dilution were the basis for the evaluation...
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THE INTERACTION BETWEEN STEEL COLUMN CHORD AND CLOSELY SPACED REINFORCEMENT.
PublikacjaNowadays, more often than before, civil engineering designers are willing to use steel build-up members composed of single or doubled cold-formed chords interconnected using different mechanical connectors. This paper subject is an analysis of cooperation of a closely spaced built-up cold-formed chord interconnected with series of bolts that are located along the length of the member in a specific spacing. This distance along the...
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Analysis of turnouts with non-linear curvature of diverging track for different train running speeds
PublikacjaThe paper deals with the issue of shaping a variable curvature in the diverging track of the railway turnout. Solution without a circular arc in the central zone, comprising two zones of non-linear curvature, of the same length, having zero curvature values at the end points, was adopted as a model, on the basis of the previously conducted dynamic tests. Optimum type of curvature was selected from the point of view of the kinematic...
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Negative Poisson’s ratio from pentagons: A new auxetic structure combining three different auxetic mechanisms
PublikacjaA novel class of two-dimensional auxetic structures based on the pentagon motif is proposed. Their mechanical properties are investigated by combining molecular mechanics simulations with a simple three-parameter mechanical model which assumes perfectly elastic behavior. It is predicted that the proposed structures – termed as double re-entrant honeycomb – may possess unique mechanical characteristics, which include complete and...
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Organic pollutants photodegradation increment with use of TiO2 nanotubes decorated with transition metals after pulsed laser treatment
PublikacjaAmong various titanium(IV) oxide (TiO2, titania) structures, 1D nanotubes (TiO2 NTs) produced during the two-electrode anodization process, are extensively utilized in sensors or supercapacitors as well as in photo(electro)catalytic water splitting. However, due to wide bandgap and fast electron-hole recombination additional modifications, mostly concerned on materials surface, are required. According to the recent research, TiO2...
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Usage of Memi-Markov Process in Operation Evaluation of Diesel Engine
PublikacjaIn paper, the proposition of quantitative evaluation of operation using semi-Markov processes theories has been presented. Basic assumptions, essential for creating mathematical model on example of diesel engine were shown. Special attention was given to practical aspects of using established mathematical model. Example of characteristic of analysed process - temporary distribution of probability was assigned.
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A remark on singular sets of vector bundle morphisms
PublikacjaIf characteristic classes for two vector bundles over the same base space do not coincide, then the bundles are not isomorphic. We give under rather common assumptions a lower bound on the topological dimension of the set of all points in the base over which a morphism between such bundles is not bijective. Moreover, we show that this set is topologically non-trivial.
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Chitosan and polyvinyl alcohol nanocomposites with cellulose nanofibers from ginger rhizomes and its antimicrobial activities
PublikacjaThe inhibitory effect of 5% GNF bionanocomposites against Bacillus cereus, Escherichia coli, Staphylococcus aureus and Salmonella typhimurium indicated good antibacterial activity of the nanocomposites due to the addition of GNF in the biopolymer matrices. The use of GNF will help to increase the economic values of agricultural waste and the characteristic properties of GNF derived bionanocomposites could be possibly used in medical...
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Parametry mechaniczne platformy roboczej na podstawie badań DMT
PublikacjaNośność platformy roboczej określana jest w sposób analogiczny do nośności podłoża uwarstwionego, w którym warstwa wierzchnia zbudowana z gruntu niespoistego spoczywa na słabonośnym podłożu z gruntu spoistego. Badanie DMT wykorzystano do wyznaczenia parametrów wytrzymałościowych podłoża (kąta tarcia wewnętrznego warstwy górnej i wytrzymałości na ścinanie bez odpływu podłoża słabonośnego) oraz do wyznaczenia modułu odkształcenia...
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Foucault's pendulum. Uncomplicated tool in the study of geodesy and cartography
PublikacjaModern education methods often refer to the sophisticated and technologically advanced methods. In the process of education the latest technologies and inventions should be presented. Modern research achievements becomes an indispensable part of the technical studies. However the learning process of an engineer should refer to the standard methods of measurement and well known fundamental instruments. One of the simplest devices...
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Digital Fingerprinting based on Quaternion Encryption for Image Transmission
PublikacjaIn this paper a new digital fingerprinting scheme for images is proposed. A proposed method is based on quaternion encryption with Cipher Block Chaining (CBC) mode of operation. Quaternions are hyper-complex numbers of rank 4 and thus often applied to mechanics in three-dimensional space. The encryption algorithm is designed for grey-tone images. For purpose of encryption, the algorithm uses the rotation of data vectors presented...
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Rotating rod and ball
PublikacjaWe consider a mechanical system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points. The ball is reflected elastically when colliding with the rod and moves freely between consecutive hits. A sliding motion along the rod is also allowed. We prove the existence and uniqueness of the motion with a given position and velocity at a certain time...
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CFD Simulations and Tests of a Prototype Flow Control Valve
PublikacjaIn this paper a prototype of a flow control valve is described and numerically simulated. The flow control valve is used in hydraulic systems to maintain constant fluid flow despite changing loads of a receiver. The standard construction of this type of valves is modified mainly by eliminating the spring. The prototype consists the hydrostatically unloaded throttle valve and pressure ratio valve substituting pressure difference...
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Modelling of Mechanical Behaviour of High-Frequency Piezoelectric Actuators Using Bouc-Wen Model
PublikacjaThe paper presents the application of a modified, symmetrical Bouc-Wen model to simulate a mechanical behaviour of high-frequency piezoelectric actuators (PAs). In order to identify parameters of the model, a two-step algorithm was utilized. In the first stage, the mechanical parameters were identified by taking into account their bilinear variability and using a square input voltage waveform. In the second step, the hysteresis...
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The study on the appearance of deformation defects in the yacht lamination process using an AI algorithm and expert knowledge
PublikacjaThis article describes the application of the A-priori algorithm for defining the rule-based relationships between individual defects caused during the lamination process, affecting the deformation defect of the yacht shell. The data from 542 yachts were collected and evaluated. For the proper development of the algorithm, a technological process of the yacht lamination supported by expert decisions was described. The laminating...
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Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers
PublikacjaIn this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28) segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD). Measurements were performed with the interferometer illuminated by two broadband sources operating...
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Effect of adhesive compliance in the assessment of soft adhesives with the wedge test
PublikacjaWedge tests are usually analysed assuming that the free, unbonded members may be treated as encastré cantilever beams. However, if the adhesive layer is sufficiently flexible (e.g., due to low elastic modulus), then significant strain in the bonded region may occur and lead to modification of the behaviour outside this region. Using in conjunction a sensitive strain gauge method on asymmetric wedge tests and a mathematical analysis...