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Search results for: MARINE PROPULSION SHAFTING, BEARING LUBRICATION, FLUID-STRUCTURE INTERACTION, FINITE-ELEMENT METHOD, OPTIMIZATION
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On some properties of 2d spectral finite elements in problems of wave propagation
PublicationW pracy przedstawiono sformułowanie dwuwymiarowych elementów spektralnych stosowanych w symulacji propagacji fal prowadzonych. Zbadano własności tych elementów pod kątem występowania form pasożytniczych, odporności na dystorsję siatki oraz zbadano wpływ kształtu elementu na krzywe dyspersji
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On the convergence of a finite-difference discretization à la Mickens of the generalized Burgers–Huxley equation
PublicationIn this note, we establish the property of convergence for a finite-difference discretization of a diffusive partial differential equation with generalized Burgers convective law and generalized Hodgkin–Huxley reaction. The numerical method was previously investigated in the literature and, amongst other features of interest, it is a fast and nonlinear technique that is capable of preserving positivity, boundedness and monotonicity....
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Robot Eye Perspective in Perceiving Facial Expressions in Interaction with Children with Autism
PublicationThe paper concerns automatic facial expression analysis applied in a study of natural “in the wild” interaction between children with autism and a social robot. The paper reports a study that analyzed the recordings captured via a camera located in the eye of a robot. Children with autism exhibit a diverse level of deficits, including ones in social interaction and emotional expression. The aim of the study was to explore the possibility...
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Predicting the seismic collapse capacity of adjacent SMRFs retrofitted with fluid viscous dampers in pounding condition
PublicationSevere damages of adjacent structures due to structural pounding during earthquakes have emphasized the need to use some seismic retrofit strategy to enhance the structural performance. The purpose of this paper is to study the influence of using linear and nonlinear Fluid Viscous Dampers (FVDs) on the seismic collapse capacities of adjacent structures prone to pounding and proposing modification factors to modify the median...
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Structure and electrical properties of Y, Fe-based perovskite mixed conducting composites fabricated by a modified polymer precursor method
PublicationIn this work, samples of Y0.07Sr0.93Ti1-xFexO3-d with 20, 40, 60 and 80 mol% of iron amount were prepared by a low-temperature polymer precursor method. The SEM-EDS analysis proved that analyzed Y0.07Sr0.93Ti1-xFexO3-d samples were composites of two Ti- and Fe-rich perovskite samples. This kind of composite consists of two phases in which one has a good ionic and the other electronic conductivity, which makes such a composite a...
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MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
PublicationNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous...
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Synthesis, structure, DNA binding and anticancer activity of mixed ligand ruthenium(II) complex
PublicationIn order to obtain a potential chemotherapeutic which is not affected on the normal BALB/3T3 cell line, a new arene ruthenium(II) complex {[RuCl(L1)(η6-p-cymene)]PF6}2 · H2O has been synthesized by a direct reaction of precursor, [{(η6-p-cymene)Ru(μ-Cl)}2Cl2], with N,N-chelating ligand (L1 - 2,2′-bis(4,5-dimethylimidazole). The compound has been fully characterized by elemental analysis, X-ray diffraction, IR, UV–Vis and 1H, 13C...
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Evaluation of working spaces' technical condition of marine diesel engine on the basis of operation research
PublicationThe paper presents the method of evaluation of the technical state of working spaces of a marine diesel engine at the reduced control susceptibility. The method foresees making diagnosis on the basis of the measurements of exhaust gas pressure in the channels connecting engine cylinders with turbocharger's turbine. In the beginning of the article the research objects are characterized i.e. ZVIEZDA main engine of M401 type and the...
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HEALTH MONITORING OF A COMPRESSION IGNITION ENGINE FED WITH DIFFERENT LOW-SULPHUR MARINE FUELS BY ENDOSCOPIC IMAGE PROCESSING AND ANALYSIS
PublicationThis article characterises the methodology for the endoscopic testing of a laboratory diesel engine used for testing marine fuels. The ‘Shadow’ measurement method used in the XLG3 type EVEREST digital endoscope, for quantitative and qualitative identification of detected surface defects, was approximated. Representative endoscopic images of the elements limiting the working space of the research engine are demonstrated, having...
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Thermal efficiency investigations on the self-ignition test engine fed with marine low sulfur diesel fuels
PublicationWithin the article an issues of implementing the new kinds of marine diesel fuels into ships’ operation was described taking into ac-count restrictions on the permissible sulphur content introduced by the International Maritime Organization. This is a new situation for ship owners and fuel producers, which forces the necessity to carry out laboratory research tests on especially adapted engine stands. How to elaborate the method...
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Technical evaluation of marine auxiliary diesel engine on the basis of parameters synchronous generator
PublicationThe article presents a method for evaluating the technical condition of selected structural elements of the reciprocating internal combustion engine driving a synchronous generator. Th results of measurements of the electric generator parameters are the diagnostic information source. On this basis it is possible to determine the instantaneous angular speed marine engine crankshaft which, in turn, is the basis for reasoning about...
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ENERGY AND EMISSION QUALITY RANKING OF NEWLY PRODUCED LOW-SULPHUR MARINE FUEL
PublicationThe article describes the methodology of engine tests on new types of low-sulphur marine fuels in laboratory conditions in order to conduct a comprehensive assessment of their suitability for powering full-size marine engines. The innovativeness of the proposed solution consists of adapting the laboratory Diesel Engine Test Bed to carry out experimental tests using residual and alternative fuels so that it is possible to imitate...
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Multi-objective optimization of microextraction procedures
PublicationOptimization of extraction process requiresfinding acceptable conditions for many analytes and goodperformance in terms of process time or solvent consumption. These optimization criteria are oftencontradictory to each other, the performance of the system in given conditions is good for some criteriabut poor for others. Therefore, such problems require special assessment tools that allow to combinethese contradictory criteria into...
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Multi-objective optimization of compact UWB impedance matching transformers using Pareto front exploration and adjoint sensitivities
PublicationIn this paper, a technique for fast multi-objective optimization of impedance matching transformers has been presented. In our approach, a set of alternative designs that represent the best possible trade-offs between conflicting objectives (here, the maximum reflection level within a frequency band of interest and the circuit size) is identified by directly exploring the Pareto front. More specifically, the subsequent Pareto-optimal...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results. Part II Results of life tests of multi-stage magnetic - fluid seal operating in water
PublicationThe edge criteria for magnetic-fluid seals durability research were described in previous article [24] and now the tests results are presented. The tests were made with three magnetic fluids using various magnets quantity in magnetic assemblies. If values obtained in the repeated test deviated by more than 10 % from results of the first test an additional control test was made for final characteristics. The characteristics are:...
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Experimental research on helical coil biomass boiler with oil as a heating fluid
PublicationThis paper presents an experimental research of helical coil biomass boiler with thermal oil heating agent. Heat exchanger consists of two coaxial helical coils swept by the flue gases. The burner is a single vertical retort connected to the fuel tank (wooden pellets). The boiler is a part of micro-power plant in which the heat from the boiler is exchanged with low-boiling HFE7100 to produce steam for a custom steam turbine. The...
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A new seismic control framework of optimal PIλDµ controller series with fuzzy PD controller including soil-structure interaction
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Text Categorization Improvement via User Interaction
PublicationIn this paper, we propose an approach to improvement of text categorization using interaction with the user. The quality of categorization has been defined in terms of a distribution of objects related to the classes and projected on the self-organizing maps. For the experiments, we use the articles and categories from the subset of Simple Wikipedia. We test three different approaches for text representation. As a baseline we use...
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Paraffin-Embedded Tissue as a Novel Matrix in Metabolomics Study: Optimization of Metabolite Extraction Method
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Performance and Emission Modelling and Simulation of Marine Diesel Engines using Publicly Available Engine Data
PublicationTo analyse the behaviour of marine diesel engines in unsteady states for different purposes, for example to determine the fuel consumption or emissions level, to adjust the control strategy, to manage the maintenance, etc., a goal-based mathematical model that can be easily implemented for simulation is necessary. Such a model usually requires a wide range of operating data, measured on a test stand. This is a time-consuming process...
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The finite-difference simulation of x-rays propagation through a system of lenses
PublicationThe propagation of X-ray waves through an optical system consisting of 33 aluminum X-ray refractive lenses is considered. For solving the problem, a finite-difference method is suggested and investigated. It is shown that very small steps of the difference grid are necessary for reliable computation of propagation of X-ray waves through the system of lenses. It is shown that the wave phase is a function very quickly increasing...
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The sources of contamination and reasons of damage of the flow part of the marine turbine engine in operation
PublicationThe aim of this paperis to show particular sensitivity of the flow part of the marine turbine engine to the presence of contaminations in the intake air. The contaminations form hard-to-remove deposits in the intervene channels that result in a reduced efficiency and performance of the engine. The paper classifies the contaminants according the source of their formation and their destructive force. The performed analyses and syntheses...
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Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
PublicationIn the paper, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is reexamined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the paper is to show an advantage of the proposed topology in limiting high frequency common mode voltage and bearing currents. In the laboratory setup, an induction...
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Marine Fuel Sulphur Limit Impact on Air Pollution
PublicationThe article presents calculation of Sulphur oxides percentage drop rate in marine industry recorded after 01.01.2020 when new limits, provided by International Maritime Organizations legislation, became effective. Ships’ SOx global emission was estimated and compared between 4th quarter 2019 and 1st quarter 2020. For more accurate estimation 3 seaside cities with big harbors were selected for statistical analysis. Noticeable...
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Sounding of Layered Marine Bottom - Model Investigations
PublicationThe necessary actions connected with interpretations of examining of physical properties of sea bottom structure is developing of proper procedure of modeling of the layered structure. The implementation of the acoustic waves for the determination of seabed stratification requires a precise diagnosis of the topic from both the theoretical and practical side. Little differences between the parameters of sediments, as well as irregular...
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Effect of manufacturing errors of the pad sliding surface on the performance of the hydrodynamic thrust bearing
PublicationIn the present study, investigation of the effect of manufacturing errors on the performance of large tilting pad thrust bearings has been performed, following a CFD-based Thermohydrodynamic analysis of a single pad. A 3D model has been generated, including the pad, the lubricant film and the corresponding part of the collar. The pad has been assumed to be deformed about the pivot point, due to thrust loading. Manufacturing errors...
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Hybrid finite-difference/mode-matching method for analysis of scattering from arbitrary configuration of rotationally-symmetrical posts
PublicationW artykule przedstawiona została metoda hybrydowa pozwalająca na analizę zjawiska rozpraszania od dowolnej konfiguracji obiektów o osiowej symetrii. Proponowana metoda oparta jest na reprezentacji obiektu lub dowolnej konfiguracji obiektów poprzez zastępczy obiekt kulisty ze znanymi warunkami brzegowymi. W analizie pojedynczego obiektu wykorzystana została metoda hybrydowa stanowiąca połączenie metody różnic skończonych z metodą...
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Application of a hybrid finite difference-mode matching method to the analysis of circular cavities loaded with cylindrical metallic objects
PublicationW artykule przedstawiono badania rezonatorów cylindrycznych zawierających obiekty cylindryczne o dowolnym przekroju poprzecznym z wykorzystaniem metody hybrydowej stanowiącej połączenie metody różnic skończonych z metodą dopasowania rodzajów. W ramach badań określono częstotliwości rezonansowe dla wybranych struktur rezonatorów. Wyniki numeryczne zostały zweryfikowane eksperymentalnie.
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Analysis of scattering from arbitrary configuration of cylindrical objects using hybrid finite-difference mode-matching method
PublicationW artykule przedstawiono nową metodę hybrydową stanowiącą połączenie metody różnic skończonych z metodą dopasowania rodzajów, pozwalającą na analizę obiektów cylindrycznych o dowolnym przekroju poprzecznym. W prezentowanej metodzie poszczególne obiekty reprezentowane są poprzez wielorodzajową macierz impednacyjną zdefiniowaną na powierzchni bocznej zastępczego cylindra zawierającego badany obiekt. Celem określenia parametrów rozproszenia...
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Multi-objective optimization of expensive electromagnetic simulation models
PublicationVast majority of practical engineering design problems require simultaneous handling of several criteria. For the sake of simplicity and through a priori preference articulation one can turn many design tasks into single-objective problems that can be handled using conventional numerical optimization routines. However, in some situations, acquiring comprehensive knowledge about the system at hand, in particular, about possible...
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Chapter 2: Modelling and analysis of rotor with magnetic bearing system
PublicationThe paper is concerned with rotor magnetic bearing system modelling. Such system is a relatively complex electromechanical system and can be considered as typical mechatronic one. The port-based modelling of physical systems has been used to obtain discrete-continuous model of considered system. Proposed approach enables to obtain reduced low-order lumped parameter representation of the system including gyroscopic interactions....
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Periodic and impulsive lubrication of hip joint with stochastic rough surface.
PublicationNiniejsza praca przedstawia porównanie wartości nośności uzyskanych numerycznie dla niestacjonarnego smarowania impulsywnego oraz niestacjonarnego smarowania periodycznego sferycznego stawu biodrowego człowieka. W obu przypadkach przyjęto, że smarująca ciecz synowialna ma własności lepkosprężyste a występy chropowatych powierzchni chrząstki stawowej zmieniają się losowo. Charakterystyki zmiennych w czasie rozkładów wartości ciśnienia...
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Impulsive lubrication of hip joint for hypo-elastic cartilage model
PublicationPraca rozwiązuje problem smarowania stawu biodrowego człowieka w warunkach niestacjonarnych z uwzględnieniem hypo-sprężystych (pod-sprężystych) właściwości odkształcalnej szkieletu chrząstki stawowej. Prezentowane są rozkłady wartości ciśnienia hydrodynamicznego oraz zmienne w czasie rozkłady wartości sił nośnych.
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Stochastic approach to the dynamics of marine floating object
PublicationAnalizowany jest ruch jednostki pływającej z uwzględnieniem w równaniach stochastycznych nieliniowości, występującej w wymuszeniach zewnętrznych działających na obiekt. Stochastyczne równania różniczkowe są zapisane dla sprzężonych ruchów symetrycznych.
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On the convergence of a nonlinear finite-difference discretization of the generalized Burgers–Fisher equation
PublicationIn this note, we establish analytically the convergence of a nonlinear finite-difference discretization of the generalized Burgers-Fisher equation. The existence and uniqueness of positive, bounded and monotone solutions for this scheme was recently established in [J. Diff. Eq. Appl. 19, 1907{1920 (2014)]. In the present work, we prove additionally that the method is convergent of order one in time, and of order two in space. Some...
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Modelling, Simulation and Optimization of the Wavemaker in a Towing Tank
PublicationThe paper analyses the problem of experimental identification (frequency response), modelling and optimization of the towing tank wavemaker in the Scilab/Xcos environment. The experimental identification of the objects (the towing tank wavemaker placed in the hydrodynamic laboratory of the CTO S.A. Ship Design and Research Centre (CTO)) and the implementation of the models in the simulation environment, enable to perform: 1. tuning...
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Application analysis of a hybrid solid oxide fuel cell-gas turbine system for marine power plants
PublicationThe results of theoretical studies of the possibilities of using hybrid solid oxide fuel cell–gas turbine (SOFC-GT) systems for marine power plants are presented. A 500 kW auxiliary marine power plant scheme using stacks of SOFCs in combination with a regenerative gas turbine operating with over-expansion based on our recent patent application is proposed. The results of mathematical modelling showed the opportunity to obtain a...
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The use of GFRP tubes as load-bearing jackets in concrete-composite columns
PublicationThe paper presents the fields of applications of polymer composites in building structures. The use of composite glass fibre tubes is discussed in more detail. The laboratory methods used to test the mechanical properties of these pipes are presented. An original research program is presented, including six concrete-filled glass fibre tubes. The cylinders and columns made in this way were tested for their axial load capacity. Conclusions...
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Herbarium of Division of Marine Biology and Ecology as the Primary Basis for Conservation Status Assessments in the Gulf of Gdańsk
PublicationThe dataset titled Herbarium of Division of Marine Biology and Ecology University of Gdańsk (DMBE) is a research herbarium encompassing specimens of vascular plants and algae hosted by the Laboratory of Marine Plant Ecology at the University of Gdańsk, Poland. The aim of Herbarium is to preserve marine plant and algae collections mostly from the Gulf of Gdańsk, but the herbarium also holds specimens from other parts of the world.
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Small Antenna Design Using Surrogate-Based Optimization
PublicationIn this work, design of small antennas using efficient numerical optimization is investigated. We exploit variable-fidelity electromagnetic (EM) simulations and the adaptively adjusted design specifications (AADS) technique. Combination of these methods allows us to simultaneously adjust multiple geometry parameters of the antenna structure of interest in a computationally feasible manner, leading to substantial reduction of the...
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Metoda energetyczno-czasowa oceny działania poprzecznych łożysk ślizgowych. Energy-time method of the estimation of work of slide bearing
PublicationZaproponowano interpretację wartościującą działania, które (podobnie jak przedstawione w mechanice klasycznej działania Hamiltona i Maupertiusa oraz działanie wynikające ze zmiany pędu ciała) jest rozpatrywane jako wielkość fizyczna o jednostce miary zwanej dżulosekundą [dżulxsekunda]. Przedstawiono oryginalną metodę analizy i oceny działania łożyska ślizgowego z uwzględnieniem jego niezawodności i bezpieczeństwa funkcjonowania....
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The OptD-multi method in LiDAR processing
PublicationNew and constantly developing technology for acquiring spatial data, such as LiDAR (light detection and ranging), is a source for large volume of data. However, such amount of data is not always needed for developing the most popular LiDAR products: digital terrain model (DTM) or digital surface model. Therefore, in many cases, the number of contained points are reduced in the pre-processing stage. The degree of reduction is determined...
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Trophic Transfer of Mercury in a Temperate Marine Food Web, Southern Baltic Sea
PublicationMercury (Hg) is considered to be one of the most dangerous global environmental pollutants. The toxicity and bioavailabilityof Hg depend on its chemical form, and the greatest hazard is posed by the organomercurial compounds. Hg is introduced into the human body primarily through the consumption of fish and seafood. Despite numerous studies on Hg in marine organisms, there is still a gap in the knowledge on Hg uptake and...
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Air journal bearing utilizing near-field acoustic levitation: stationary shaft case
PublicationResults of a study to examine a unique idea of self-levitating journal bearing are presented in this paper. the idea represents a radical departure from the current bearing technology. it utilisesacoustic levitation, which relies on the sound energy radiated by an object supporting a load. acoustic levitation has been demonstrated to support loads of up to 10 kg. in order to support a load theacoustic wave emitted by the radiating...
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TIME-AND-SPACE STRUCTURE OF FORCE-DRIVEN RIGID SPHEREWAVEFIELD
PublicationThis paper introduces a time-domain, causality-inspired description of a vector-source acoustic wavefield of arbitrary time evolution, where a sphere is a practical realisation of quasi-point contact surface without which a point force would not be able to exert an impact onto non-viscous fluid. At every space location, the resulting acoustic field is described by a pair of physical variables characterising the time evolution of...
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Defining a novel domain that provides an essential contribution to site-specific interaction of Rep protein with DNA
PublicationAn essential feature of replication initiation proteins is their ability to bind to DNA. In this work, we describe a new domain that contributes to a replication initiator sequence-specific interaction with DNA. Applying biochemical assays and structure prediction methods coupled with DNA–protein crosslinking, mass spectrometry, and construction and analysis of mutant proteins, we identified that the replication initiator of the...
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Novel structure and design of compact UWB slot antenna
PublicationIn this paper, a novel structure of a compact UWB slot antenna is presented along with a simulation-driven design optimization algorithm for adjusting geometry parameters of the device. Our primary objective is to obtain small footprint of the structure while maintaining its acceptable electrical performance. It is achieved by introducing sufficiently large number of geometry degrees of freedom, including increased number of parameterized...
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Chromogenic azomacrocycles with imidazole residue: Structure vs. properties
PublicationNew diazo macrocycles linked by hydrocarbon chain bearing imidazole or 4-methylimidazole residue have been synthetized with satisfactory yield (24–55%). The structure of macrocycles was confirmed by X-ray analysis and spectroscopic methods (1H NMR, MS, FTIR). Metal cation complexation studies were carried out in acetonitrile and acetonitrile-water system. It was found that azomacrocyles form triple-decker complexes with lead(II)....
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Point cloud unification with optimization algorithm
PublicationTerrestrial laser scanning is a technology that enables to obtain three-dimensional data – an accurate representation of reality. During scanning not only desired objects are measured, but also a lot of additional elements. Therefore, unnecessary data is being removed, what has an impact on efficiency of point cloud processing. It can happen while single point clouds are displayed – user decides what he wants...
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Subsoil degradation effect in reliability analysis of the jack-up platform structure
PublicationStructural reliability analysis is considered, by FORM and SORM applied to a certain idealized soil-platform structure interaction problem due to cyclic water wave and wind loads. Wave and wind loads are random variables, whereas dead load is deterministic. Load parameters are typical for storm conditions in the Baltic Sea. The soil-structure interaction is idealized as a set of linear translational and rotational springs. Due...