Search results for: DYNAMIC SYSTEMS
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Understanding homogenous nucleation: the recent phenomenological and molecular dynamic approaches
PublicationPraca przedstawia dwa podejścia do problemu homogenicznej nukleacji. Pierwsze jest podejściem fenomenologicznym. Nukleacja jest tu rozumiana jako wzrost kropel krytycznych, które po przejściu określonego wymiaru, warunku równowagi termodynamicznej, mają tendencje do wzrostu. W tym podejściu problem wzrostu kropel oraz problem populacji kropel jest określany poprzez parametry makroskopowe. Przedstawiono nowe rozwiązania uzyskane...
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Evaluation of pitting corrosion by means of dynamic electrochemical impedance spectroscopy.
PublicationPrzeprowadzono badania stali stopowej 304L metodą dynamicznej elektrochemicznej spektroskopii impedancyjnej w warunkach liniowo zmieniającego się potencjału. Określono ogólny schemat układu elektrycznego dla elektrody ulegającej korozji. Przeprowadzone badania pozwalają na jednoczesne badanie zachowania się stali stopowej w stanie pasywnym, podczas stanu przejściowego (metastabilne tworzenie się i repasywacja wżerów) oraz w stanie...
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On fatigue safety of metallic elements under static and dynamic loads.
PublicationGłównym celem monografii było wyznaczenie współczynników bezpieczeństwa i kryteriów projektowych z uwzględnieniem wpływu obciążeń statycznych oraz naprężeń średnich i resztowych na wytrzymałość zmęczeniową przy obciążeniach okresowych i/lub stochastycznych. Uzyskano to za pomocą wyznaczonych naprężeń równoważnych i równania Soderberga. Otrzymano kryteria w postaci zamkniętej i zgodnej z wzorem Milesa na trwałość zmęczeniową oraz...
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The dynamic analysisi of cracked Thimoshenko beam by the spectral element method.
PublicationW pracy przedstawiono model belli Timoshenko z pęknięciem poprzecznym oparty o metodę elementów spektralnych. Przedstawiono wyniki propagacji fali sprężystej i jej interakcję z pęknięciem.
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Optical excitation methods in active dynamic thermography in medical diagnostics.
PublicationArtykuł zawiera opis metod pobudzania cieplnego badanych obszarów ciała ludzkiego w technice aktywnej termografii dynamicznej. Jako źródła pobudzenia cieplnego mogą być stosowane lampy podczerwieni, lampy halogenowe dużej mocy, a także lasery. W artykule opisano również algorytmy obliczeń obrazów parametrycznych.
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Dynamic electrochemical impedance spectroscopy of the first order electrode reaction
PublicationCiągłe transformaty STFT sinusoidalnego sygnału pobudzenia i odpowiedzi prądowej zostały wyznaczone dla reakcji elektrodowej pierwszego rzędu. Wyznaczono impedancję elektrody w łącznej dziedzinie czasu i częstotliwości. Wykonano pomiary dla reakcji redukcji Cd(II) na rtęciowej elektrodzie kroplowej w funkcji potencjału. Przedstawiono możliwość wyznaczenia chwilowych widm impedancyjnych. Opisano zależność rezystancji przeniesienia...
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Ionic transport in silica xerogels investigated by dynamic current voltagecharacteristics.
PublicationPodano wstępne rezultaty badania transportu ujemnych jonów w kserożelach Si02 w warunkach wysokiego gradientu temperatury w próbce, wywołanego jej ekstremalnie niską przewodnością cieplną. Uzyskane charakterystyki pozostają w zgodzie z przewidywaniami teoretycznymi. Na ich podstawie określono znak jonów, ich ruchliwość i energię aktywacji.
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Export diversification and economic development: a dynamic spatial data analysis
PublicationThis paper contributes to the empirical literature on the relationship between ‘export variety’ (export diversification) and economic development by relaxing the assumption of cross-country independence and allowing for spatial diffusion of shocks in observed and unobserved factors. Export variety is measured for a balanced panel of 114 countries (1992-2012) using very detailed information on their exports (HS 6-digit product...
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Behavior Analysis and Dynamic Crowd Management in Video Surveillance System
PublicationA concept and practical implementation of a crowd management system which acquires input data by the set of monitoring cameras is presented. Two leading threads are considered. First concerns the crowd behavior analysis. Second thread focuses on detection of a hold-ups in the doorway. The optical flow combined with soft computing methods (neural network) is employed to evaluate the type of crowd behavior, and fuzzy logic aids detection...
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A Ubiquitous System Using Semantic Knowledge in Dynamic Service Integration
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...
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DYNAMIC POSITIONING CAPABILITY ASSESSMENT BASED ON OPTIMAL THRUST ALLOCATION
PublicationThe article presents an efficient method of optimal thrust allocation over the actuators in a dynamically positioned ship, according to the DNV-ST-0111 standard, Level 1. The optimisation task is approximated to a convex problem with linear constraints and mathematically formulated as quadratic programming. The case study is being used to illustrate the use of the proposed approach in assessing the DP capability of a rescue ship....
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Ship Dynamic Positioning Based on Nonlinear Model Predictive Control
PublicationThe presented work explores the simulation test results of using nonlinear model predictive control algorithm for ship dynamic positioning. In the optimization task, a goal function with a penalty was proposed with a variable prediction step. The results of the proposed control algorithm were compared with backstepping and PID. The effect of estimation accuracy on the control quality with the implemented algorithms was investigated....
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Validation of dynamic electrochemical impedance spectrograms using autocorrelation function
PublicationValidation of impedance data is essential for checking the reliability of experimental data. Kramers – Kronig transformation is used to verify data obtained from classical Electrochemical Impedance Spectroscopy (EIS) measurements. Data obtained from Dynamic Electrochemical Impedance Spectroscopy (DEIS) could be validated in the same way, but in this case, there is no information about internal consistency between every single spectrum...
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Dynamic tests of composite footbridge segment – experimental and numerical studies
PublicationExperimental dynamic tests and numerical simulations of a 3 meters long segment of a footbridge made of polymer composites are presented in the paper. The span-length is reduced, however dimensions of cross-section are the same as the target footbridge. The segment structure is made of sandwich panels, which consist of fibre reinforced polymer (GFRP) laminates (skins) and a PET foam (core). The first part of the paper contains...
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Local electrochemical impedance spectroscopy in dynamic mode of galvanic coupling
PublicationA novel method that combines local electrochemical impedance spectroscopy and mapping in dynamicmode is proposed. Method was validated over two galvanic couplings, namely zinc/copper and cad-mium/copper. Impedance spectrum response for all measuring points was obtained by means ofsimultaneous implementation of selected range of frequencies. Proposed method allows the measure-ment in a more time-efficient manner, at the same time...
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On Dynamic Extension of a Local Material Symmetry Group for Micropolar Media
PublicationFor micropolar media we present a new definition of the local material symmetry group considering invariant properties of the both kinetic energy and strain energy density under changes of a reference placement. Unlike simple (Cauchy) materials, micropolar media can be characterized through two kinematically independent fields, that are translation vector and orthogonal microrotation tensor. In other words, in micropolar continua...
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The dynamic signature verification using population-based vertical partitioning
PublicationThe dynamic signature is an attribute used in behavioral biometrics for verifying the identity of an individual. This attribute, apart from the shape of the signature, also contains information about the dynamics of the signing process described by the signals which tend to change over time. It is possible to process those signals in order to obtain descriptors of the signature characteristic of an individual user. One of the methods...
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Dynamic characteristics of the proton exchange membrane fuel cell module
PublicationThe paper describes a fuel cell based system and its performance. The system is based on two fuel cell units, DC/DC converter, DC/AC inverter, microprocessor control unit, load unit, bottled hydrogen supply system and a set of measurement instruments. In the study presented in the paper a dynamic response of the proton exchange membrane (PEM) fuel cell system to unit step change load as well as to periodical load changing cycles...
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Timber frame houses resistant to dynamic loads - seismic analysis
PublicationThe aim of the article is to present results of seismic analysis results of two real-sized timber frame buildings subjected to seismic excitations. The first model was insulated with mineral wool, the second one with polyurethane foam. Technology and specifications involved in both models construction is based on the previously conducted experimental research on timber frame houses, including wall panels tests, wall numerical models...
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Experimental study and numerical simulation of the dynamic penetration into dry clay
PublicationTests of dry clay were carried out in a uniaxial stress state using the experimental setup which implements the split Hopkinson pressure bar method. Based on the results of these experiments, the compressive strength of clay was determined as an important element of S.S. Grigoryan’s model of the soil medium. In addition, the parameters of this model are determined from the results of experiments using the modified Kolsky method...
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On time-dependent nonlinear dynamic response of micro-elastic solids
PublicationA new approach to the mechanical response of micro-mechanic problems is presented using the modified couple stress theory. This model captured micro-turns due to micro-particles' rotations which could be essential for microstructural materials and/or at small scales. In a micro media based on the small rotations, sub-particles can also turn except the whole domain rotation. However, this framework is competent for a static medium....
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Dynamic analysis of the railway bridge span under moving loads
PublicationThe first part of this paper provides a review of the state of knowledge of the dynamic behaviour of railway bridges under moving loads. Particular attention is paid to developments in modelling railway bridge loading and dynamic vehicle-span (structure) interaction. The most important aspects determining the advancements in this area of knowledge are identified. The contemporary techniques for defining bridge span finite element...
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Computational modelling of concrete behavior under static and dynamic conditions
PublicationW artykule zaproponowano wyniki obliczeń MES dla betonu podczas dynamicznego obciążenia. Przyjęto model sprężysto-plastyczno-lepki z nielokalnym osłabieniem. Obliczenia MES dla elementów betonowych pod obciążeniem dynamicznym o różnej prędkości obciążenia porównano bezpośrednio z doświadczeniami.
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Transport properties of aqueous ionic liquid microemulsions: influence of the anion type and presence of the cosurfactant
PublicationTransport properties, viz. specific conductivity, dynamic viscosity and apparent diffusion coefficients, were measured as a function of water content in aqueous ionic liquid microemulsions containing 1-butyl-3- methylimidazolium hexafluorophosphate, [BMIM][PF6] and bis(trifluoromethanesulphonyl)imide, [BMIM][Tf2N], stabilized by the nonionic surfactant TX-100, or its mixture with a cosurfactant, i.e. butanol. The investigation covered...
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Nonlinear viscoelasticity in Three Dimensional filler reinforced rubber composites and nanocomposites
PublicationThis chapter describes the influence of three-dimensional nanofillers used in elastomers on the nonlinear viscoelastic properties. In particular, this part focuses and investigates the most important three-dimensional nanoparticles, which are used to produce rubber nanocomposites. The rheological and the dynamic mechanical properties of elastomeric polymers, reinforced with spherical nanoparticles, like POSS, titanium dioxide and...
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Cooperative control in production and logistics
PublicationClassical applications of control engineering and information and communication technology (ICT) in production and logistics are often done in a rigid, centralized and hierarchical way. These inflexible approaches are typically not able to cope with the complexities of the manufacturing environment, such as the instabilities, uncertainties and abrupt changes caused by internal and external disturbances, or a large number and variety...
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CAVER 3.0: A Tool for the Analysis of Transport Pathways in Dynamic Protein Structures
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The process of developing dynamic capabilities: The conceptualization attempt and the results of empirical studies
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Application of dynamic time warping and cepstrograms to text-dependent speaker verification
PublicationThis work provides a description of an automatic speaker verification (ASV) system. In particular, it documents the evolution of all individual stages of the proposed ASV system design from the phase of preprocessing to an operational decision making system. The aim of this research was to achieve the system of the best safety and ease of use in view of users. The objective estimation of this target has been accomplished by assessing...
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Dynamic computation of acoustic field distribution in the city area employing a supercomputer
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Nonlinear modeling of traction transformer with coiled iron core for dynamic simulation
PublicationW referacie przedstawiono wyprowadzenie zastępczego modelu obwodowego transformatora trakcyjnego o rdzeniu zwijanym do analiz zachowania sie transformatora w układzie napedowym jednostki trakcyjnej. Model zakłada nieliniowa charakterystyke magnesowania B-H i anizotropowe właściwosci magnetyczne i elektryczne zwijanego rdzenia. Wyprowadzenie modelu oparto na metodzie energetycznej Lagrange'a. Uzwojenia zostały zamodelowanie jako...
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State equations in the mathematical model of dynamic behaviour of multihull floating unit
PublicationPrzedstawiony artykuł dotyczy dynamiki wielokadłubowej jednostki pływającej typu katamaran poddanej wymuszeniom pochodzącym od falowania nieregularnego. Analiza dynamiki jednostki wielokadłubowej została przeprowadzona przy założeniu, że model układu jest modelem liniowym na który działa fala nieregularna. Model matematyczny takiego układu dynamicznego jest reprezentowany poprzez równania stanu. Zapisane zostały równania uwzględniające...
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Dynamic Modeling of COVID-19 Disease with Impact of Lockdown in Pakistan and Malaysia
PublicationBeing researchers, it is an utmost responsibility to provide insight on social issues thus, this work addresses the dynamic modeling of first and most contagious disease named as COVID-19 caused by coronavirus. The first case of COVID-19 appeared in Pakistan was on 26th February 2020 and in Malaysia on 27th February 2020; both patients had foreign travel history. In the paper, the number of total affected cases and total deaths...
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Investigations of the passive layer cracking by means of Dynamic Electrochemical Impedance Spectroscopy
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Interline power flow controller - properties and control strategy in dynamic states
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Detection of stress corrosion cracking dynamics by dynamic electrochemical impedance spectroscopy
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Dynamic mechanical thermal analysis of polyamide 6/thermoplastic polyurethane blends
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Generating optimal paths in dynamic environments using RiverFormation Dynamics algorithm
PublicationThe paper presents a comparison of four optimisation algorithms implemented for the purpose of finding the shortest path in static and dynamic environments with obstacles. Two classical graph algorithms –the Dijkstra complete algorithm and A* heuristic algorithm – were compared with metaheuristic River Formation Dynamics swarm algorithm and its newly introduced modified version. Moreover, another swarm algorithm has been compared...
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Investigation of behaviour of metal structures with polymer dampers under dynamic loads
PublicationA large number of accidents concerning structures subjected to dynamic loads have been recently observed. One of the examples of such a structure is a temporary steel grandstand erected using scaffolding system. Dynamic load that is generated by crowd movement has a significant influence on the behaviour of the structure and may lead to excessive structural vibrations. The aim of the study is to consider the idea of using polymer...
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Dynamic Analysis of the Turnout Diverging Track for HSR with Variable Curvature Sections
PublicationThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are identified and evaluated in the paper. The presented method is a universal one, it enables to assume curvature values at the beginning and end point of the geometrical layout of the turnout. The results...
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Dynamic Headspace Sampling as an Initial Step for Sample Preparation in Chromatographic Analysis
PublicationThis work represents a brief summary of the use of dynamic headspace (DHS) as a technique for sample preparation in chromatographic analysis. Despite numerous developments in the area of analyte isolation and enrichment, DHS remains one of the fundamental methods used with GC. In our opinion, interest in this technique will not diminish significantly because it conforms to stipulations of green analytical chemistry. Moreover, DHS...
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Dynamic analysis of the first stage compressor bladed disc of an aircraft engine
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Creating Dynamic Maps of Noise Threat Using PL-Grid Infrastructure
PublicationThe paper presents functionality and operation results of a system for creating dynamic maps of acoustic noise employing the PL-Grid infrastructure extended with a distributed sensor network. The work presented provides a demonstration of the services being prepared within the PLGrid Plus project for measuring, modeling and rendering data related to noise level distribution in city agglomerations. Specific computational environments,...
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Active Dynamic Thermography imaging of wound healing processes in cardio surgery
PublicationThe surgery is a branch of medicine, that is integrally connected to wounds. Despite using sterile tools and compliance with aseptic rolls, some of the surgery wounds become infected. In clinical practice there is a lack of cheap, objective methods and tools for quantitative definition and estimation of the surgery wound healing progress. This paper presents preliminary results of Active Dynamic Thermography (ADT) parametric imaging...
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Quasi-Static and Dynamic Testing of Carbon Fiber Reinforced Magnesium Composites
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Supporting High-Tech Crime Investigation through Dynamic Service Integration
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The study on dynamic properties of monolithic ball end mills with various slenderness
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Recognition of two-phase flow patterns with the use of dynamic image analysis
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Two-phase flow structure assessment based on dynamic image analysis
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