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Three dimensional simulations of FRC beams and panels with explicit definition of fibres-concrete interaction
PublikacjaHigh performance concrete (HPC) is a quite novel material which has been rapidly developed in the last few decades. It exhibits superior mechanical properties and durability comparing to normal concrete. HPC can achieve also superior tensile performance if strong fibres (steel or carbon) are implemented in the matrix. Thus, there exist the unabated interest in studying how the addition of different types of fibres modifies the...
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The influence of feed rate and shear forces on the devulcanization process of ground tire rubber (GTR) conducted in a co-rotating twin screw extruder
PublikacjaThe search for new ways to recycling of rubber waste has been the aim of many studies conducted by research centers and companiesworldwide. The results of our investigations on the process of continuous thermomechanical devulcanization of ground tire rubber using a twin screw extruder are presented.We used a co-rotating twin screw extruder with a special configuration of plasticizing unit, enabling generation of considerable shear...
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Synthesis and characterisation of polyurethane elastomers with semi-products obtained from polyurethane recycling
PublikacjaIn this work polyurethane elastomers were synthesised by using different mixtures of a petrochemical and glycerolysate polyols and 4,4-diphenylmethane diisocyanate (MDI). Glycerolysate polyol was produced from polyurethane foam decomposition using crude glycerine as a decomposition agent. The structure and thermal properties of obtained semi-product were similar to the polyol used in the synthesis of original foam. Glycerolysate...
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Clay-filled starch films. Part I: Effect of clay kind and glycerol concentration on functional properties of composites
PublikacjaThe aim of this work was to improve the mechanical and water barrier properties of composite filmsprepared from starch and clays, plasticized with glycerol at different concentrations. The effects ofhydrophilic Closite Naþand Nanomer PGV were compared with that exerted by organicallymodifiedmorehydrophobicNanofil2 and NanoBent ZR-1. The antimicrobial activity of compositescontaining hydrophobic clays was also investigated. The hydrophilic...
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Weldability of pipe grade polyethylenes as realized from thermal and mechanical properties assessments
PublikacjaSince polyethylene (PE) has been widely accepted for the production of high-pressure fluid conveying pipelines, studies devoted to weldability of PE connections were always of major importance. In this study, two industrial PE grades designed for pipe production, namely PE80 and PE100, were injection molded, cut, and then welded as PE100-PE100, PE100-PE80, and PE80-PE80. The heat-welded joints were assessed by differential scanning...
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Use of response surface methodology in characterization of properties of recycled high density polyethylene/ground tire rubber compositions
PublikacjaSearching for newways to utilize rubber and polymerwaste has been the focus of many studies conducted by research centers and companies worldwide. In this study, the influence of extrusion conditions on the properties of thermoplastic compositions containing post-production recycled high density polyethylene (PE-HD) and ground tire rubber (GTR) at 50:50 mass ratiowas examined. Response Surface Methodology (RSM) was used to determine...
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The influence of screw configuration and screw speed of co-rotating twin screw extruder on the properties of products obtained by thermomechanical reclaiming of ground tire rubber
PublikacjaThe results of our investigations on the process of continuous thermomechanical reclaiming of ground tire rubber (GTR) carried out using a twin screw extruder are presented.We used a co-rotating twin screw extruder with a special configuration of plasticizing unit, enabling generation of considerable shear forces. The influence of screw configuration and screw speed on breaking of chemical crosslink bonds contained in ground tire...
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Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle
PublikacjaDue to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different...
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Effect of Tool Positioning Factors on the Strength of Dissimilar Friction Stir Welded Joints of AA7075-T6 and AA6061-T6
PublikacjaFriction Stir Welding (FSW) is a solid-state bonding technique. There are many direct and indirect factors affecting the mechanical and microstructural properties of the FSW joints. Tool offset, tilt angle, and plunge depth are determinative tool positioning in the FSW process. Investigating the effect of these factors simultaneously with other parameters such as process speeds (rotational speed and translational speed) and tool...
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Experimental and numerical investigations of ultimate strength of degradated structures
PublikacjaThe presented work investigates the corrosion influence on the structural behaviour of structural elements. Nine welded large-scale stiffened plates, and 30 standard small specimens have been subjected to the accelerated marine immersed conditions. After corrosion testing, the specimens have been accurately measured in terms of surface characteristics. The coupon specimens were furtherly subjected to tensile loading to develop...
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An attempt to mechanistically explain the viscoelastic behavior of transparent epoxy/starch-modified ZnO nanocomposite coatings
PublikacjaThe effects of bare and starch-modified ZnO (ZnO-St) nanoparticles on viscoelastic and mechanical properties are studied by dynamic mechanical and tensile analyses. Transparent epoxy-based nanocomposite films are prepared by incorporating bare or starch-modified ZnO particles into the epoxy matrix. The results demonstrated that ZnO particles hindered the curing reactions and hence the final properties of the cured epoxy. As a result,...
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Experimental investigations on the mechanical properties and damage detection of carbon nanotubes modified crumb rubber concrete
PublikacjaThis study presents a modified crumb rubber (MCR) concrete design mix reinforced with multi-walled carbon nanotubes (MWCNTs), mechanical characterization, and cracking monitoring using the acoustic emission (AE) technique. The results showed that the bridging effect of MWCNTs and MCR in the concrete mix mitigated the shortcomings of MWCNT-MCR concrete and improved the flexural and compressive strengths by 18.3% and 26.5%, respectively,...
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublikacjaMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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Mechanical and physical assessment of epoxy, mineral, solvent-based, and water-soluble coating materials
PublikacjaThis paper assesses the behavior of mineral, epoxy (EP), solvent, and water-soluble coatings when exposed to salt and regular water for 28 days. Also, it evaluates the pull-off adhesion strength of the same coating materials applied to concrete slabs saturated with oil and water and dried with two different processes: air-dried for 28 days and air-dried for 14 days plus 14 days in the oven at 70 °C. Properties such as carbonation,...
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Nonlinear dynamic analysis of the pure “buckling” mechanism during blow-out trauma of the human orbit
PublikacjaConsidering the interplay between orbital bones and intraorbital soft tissues, commonly accepted patterns of the blow-out type of trauma within the human orbit require more thorough investigation to assess the minimal health-threatening impact value. Two different three-dimensional finite element method (FEM) models of the human orbital region were developed to simulate the pure “buckling” mechanism of orbital wall fracture in...
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Ground Tire Rubber Filled Flexible Polyurethane Foam—Effect of Waste Rubber Treatment on Composite Performance
PublikacjaThe application range of flexible polyurethane (PU) foams is comprehensive because of their versatility and flexibility in adjusting structure and performance. In addition to the investigations associated with further broadening of their potential properties, researchers are looking for new raw materials, beneficially originated from renewable resources or recycling. A great example of such a material is ground tire rubber (GTR)—the...
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Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
PublikacjaThis study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol...
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Electrochemical approach to evaluate the interlayer adhesion of organic coatings
PublikacjaZastosowano elektrochemiczną spektroskopię impedancyjną do wyznaczania międzywarstwowej adhezji w powłokach organicznych. Zbadano różne zestawy powłok do ochrony samochodów. Zastosowano dwie elektrody wykonane z prądoprzewodzącego tuszu umieszczone pomiędzy warstwami powłokowymi. Stwierdzono, że utrata adhezji międzywarstwowej następuje podobnie jak zmiany energii aktywacji przewodnictwa jonowego w obszarze międzywarstwowym. Uzyskane...
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Interactive Information Search in Text Data Collections
PublikacjaThis article presents a new idea for retrieving in text repositories, as well as it describes general infrastructure of a system created to implement and test those ideas. The implemented system differs from today’s standard search engine by introducing process of interactive search with users and data clustering. We present the basic algorithms behind our system and measures we used for results evaluation. The achieved results...
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THE INFLUENCE OF MANUFACTURING OVERSIZING ON POSTWELDING DISTORTIONS OF THE FILLET WELDED JOINT
PublikacjaWelding proces is basic joining technique in shipbuilding. Such method generated welding distortions which cause a lot of problems during the manufacturing process. In the literature it is proposed wide spectrum of suggestions for a correct estimation of welding deformation in particular angular deformation in the fillet welded T joint. In the work influence of oversizing of weld on angular distortions of joint is presented basing...
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Numerical and experimental investigation of thermal convection near electric devices with vertical channels
PublikacjaThis paper presents the results of numerical and experimental investigation of thermal convection near heat emitting surfaces of an electric device. For the intensification of thermal convection, special vertical channels were formed near the heat emitting surfaces of the device. An experimental test has proved that there is an optimal length of the channels – thermal convection is the most intensive then. Air velocity vectors...
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Similarity Measures for Face Images: An Experimental Study
PublikacjaThis work describes experiments aimed at finding a straightforward but effective way of comparing face images.We discuss properties of the basic concepts, such as the Euclidean, cosine and correlation metrics, test the simplest version of elastic templates, and compare these solutions with distances based on texture descriptors (Local Ternary Patterns). The influence of selected image processing methods (e.g. bilateral ltering)...
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New Tool for Examining QoS in the VToIP Service
PublikacjaThis paper is dedicated to the subject of measuring QoS in the Video Telephony over IP (VToIP) service. QoS measurement models in general and then models designed specifically for measuring QoS in the VToIP service are presented. A new numerical tool for examining the quality of VToIP video streams VToIP is described. The tool’s functionality is then put to the test in a number of analysis scenarios. The results and insights gained...
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Conducted EMI Propagation Paths in DC-AC Hard Switching Converter
PublikacjaIn order to limit the electromagnetic interference (EMI) in power electronics devices, knowledge about the phenomena connected with EMI generation and propagation is necessary. This papers describes the propagation paths in the 3 phase voltage source inverter using wide-band simulation and laboratory test with the signal processing method Wiener filtering, where the transfer functions between voltage across switches and the perturbation...
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Very high altitude micro air vehicle deployment method
PublikacjaThe paper presents the original work and method for high altitude micro air vehicle deployment. The method is based on the scientific ballooning, and adapted for stratospheric flight of commercial off-the-shelf micro air vehicle in flying wing configuration. The High Altitude Micro Air Vehicle, built for this research, was deployed during a test experiment at the lower level of the stratosphere. The results of the experiment and...
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Niekonwencjonalne koła pojazdów
PublikacjaPrzedstawiono sposoby zapobiegania skutkom utraty ciśnienia w oponach pneumatycznych. Zaprezentowano koła niepneumatyczne, zastosowane w pojeździe księżycowym. Omówiono wyniki badań kół kompozytowych. Przedstawiono najnowsze rozwiązania konstrukcyjne koł niepneumatycznych przeznaczonych do pojazdów mechanicznych.
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Numerical modelling of different airbag folding patterns and their influence on occupant responses in frontal vehicle impact
PublikacjaThis paper presented a procedure for airbag folding for the application in occupant safety studies and analysed the influence of different airbag folding patterns on the occupant severity in frontal impact. Airbags were folded in two patterns: zig-zag and top-roll, using two folding techniques: Initial Metric Method and Explicit Folding. The explicit folding was found to be more expensive in terms of preparation time. However,...
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From Bioink to Tissue: Exploring Chitosan-Agarose Composite in the Context of Printability and Cellular Behaviour
PublikacjaThis study presents an innovative method for producing thermosensitive bioink from chitosan hydrogels saturated with carbon dioxide and agarose. It focuses on a detailed characterisation of their physicochemical properties and potential applications in biomedicine and tissue engineering. The ORO test approved the rapid regeneration of the three-dimensional structure of chitosan–agarose composites in a unidirectional bench press...
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Changes in evaporation patterns and their impact on Climatic Water Balance and river discharges in central Poland, 1961–2020
PublikacjaThis study investigates the changes in precipitation and evaporation patterns and their impact on Climatic Water Balance and river discharges in central Poland from 1961 to 2020. The analysis focuses on two “normal” periods, 1961–1990 and 1991–2020 (according to the World Meteorological Organization). Bartlett’s test and the Kruskal–Wallis rank sum test were used to assess the homogeneity of variances and compare distributions...
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Numerical Method for Stability Testing of Fractional Exponential Delay Systems
PublikacjaA numerical method for stability testing of fractional exponential systems including delays is presented in this contribution. We propose the numerical test of stability for a very general class of systems with a transfer function, which includes polynomials and exponentials of fractional powers of the Laplace variable s combined with delay terms. Such a system is unstable if any root of its characteristic equation, which usually...
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Inflation Forecast or Forecast(s) Targeting?
PublikacjaThe paper refers to L.E.O. Svensson’s concept of inflation forecast targeting (IFT) and its implementation by central banks of Sweden, Norway and the Czech Republic. The study focuses on (1) inflation forecasts published by selected central banks, i.e.headline inflation and core or monetary policy-relevant (MPR) inflation, which are made on the assumption of endogenous instrument rate, (2) one-year consumer...
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Tripping of F-type RCDs for High-Frequency Residual Currents
PublikacjaResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs...
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Juices from non-typical edible fruits as health-promoting acidity regulators for food industry
PublikacjaThe study verifies the possibility of application of juices from selected fruits characterized by the high antioxidant potential as natural acidity regulators with improved nutritional properties. The tested non-typical fruits included mirabelle plum, sea buckthorn and blue-berried honeysuckle. Beetroot juice whose pH is about 6.0 served as a model food product. Potentiometric titration was used to compare the efficacy of tested...
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublikacjaThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...
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Analysis of antibiotic resistance in Escherichia coli isolated from the Reda River and the Oliwski Stream using basic statistical methods = Zastosowanie metod ststystycznych do analizy antybiotykoodporności bakterii wskaźnikowych pochodzących z rzeki Redy i Potoku Oliwskiego
PublikacjaIn this study distribution of antimicrobial resistance patterns among fecal indicator bacteria (Escherichia coli and Enterococcus spp.) was examined in two watercourses. The susceptibility analyses were carried out against the antimicrobial agents, important in treating human E. coli and enterococcal infection. Water samples were obtained from the Oliwski Stream and from the Reda River. On each watercourse the five representative...
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HILS for the Design of Three-Wheeled Mobile Platform Motion Surveillance System with a Use of Energy Performance Index
PublikacjaCurrent tendency in mechatronic design requires the use of comprehensive development of an environment, which gives the possibility to prototype, design, simulate and integrate with dedicated hardware. The paper discusses the Hardware-In-the-Loop Simulations (HILS) mechatronic technique, used during the design of the surveillance system based on energy performance index. The presented test configuration (physical controller – emulated...
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Effects of deviations from thermo-rheologically simple behavior of asphalt mixes in creep on developing of master curves of their stiffness modulus
PublikacjaThe paper presents the deviations from the thermo-rheologically simple behavior of asphalt mixes and their effects on the developing of master curves of stiffness modulus. Eleven different mixes were tested in three point bending test under constant load at temperatures –20°C, –10 °C and 0 °C, and in some cases at +10 °C. The test method was developed at the Gdansk University of Technology, Poland. The applied stress level was...
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3D X-ray Micro-CT Analysis of Rebar Corrosion in Reinforced Concrete Subjected to a Chloride-Induced Environment
PublikacjaThe paper presents experimental investigations of the concrete cover protective ability to coun-teract rebar corrosion in reinforced concrete cubes. To study and quantify the consequences of corrosion a reinforced concrete sample was subjected to chloride-induced environment in order to get corroded and combined with un-corroded sample. Chloride-accelerated technique can in-duce a high degree of corrosion within at a controlled...
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Tripping of F-type RCDs for high-frequency residual currents
PublikacjaResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs are...
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Laboratory fatigue assessment of large geocomposite-reinforced double-layered asphalt concrete beams
PublikacjaGeosynthetic reinforcement of asphalt layers has been used for several decades. Evaluation of the influence of these materials on pavement fatigue life is still ongoing, especially for new types of geocomposites. This paper presents the evaluation of fatigue performance of large asphalt concrete beams reinforced with a new type of composite in which square or hexagonal polypropylene stiff monolithic paving grid with integral junctions...
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Three-dimensional geographically weighted inverse regression (3GWR) model for satellite derived bathymetry using Sentinel-2 observations
PublikacjaCurrent trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favourable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment...
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Filter-Hilbert Method for Automatic Correction of Non-Anechoic Antenna Measurements with Embedded Self-Calibration Mechanism
PublikacjaOne of the most important steps in the process of antenna development involves measurements of its prototype. Far-field performance of radiators is normally characterized in strictly controlled environments such as anechoic chambers which can ensure certification-grade accuracy. Unfortunately, they are also characterized by high construction costs which might not be justified for low-budget research and/or teaching-related activities....
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Laboratory fatigue assessment of large geocomposite-reinforced double-layered asphalt concrete beams
PublikacjaGeosynthetic reinforcement of asphalt layers has been used for several decades. Evaluation of the influence of these materials on pavement fatigue life is still ongoing, especially for new types of geocomposites. This paper presents the evaluation of fatigue performance of large asphalt concrete beams reinforced with a new type of composite in which square or hexagonal polypropylene stiff monolithic paving grid with integral junctions...
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Ranking of ecotoxisity tests for underground water assessment using the Hasse diagram technique
PublikacjaThe present study deals with the novel application of the Hasse diagram technique (HDT) for the specific ranking of ecotoxicity tests capable of assessment of underground water quality. The area studied is a multi-municipal landfill in the northern Poland. The monitoring network of the landfill constitutes of 27 piezometers for underground water monitoring and two observation points at surface water courses. After sampling, chemical...
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Mikrofiltrowany koncentrat soku brzozowego jako innowacyjny, trwały środek spożywczy o wysokiej wartości odżywczej
PublikacjaIntroduction. The forest environment becomes an increasingly popular place of obtaining raw materials, and one of the most promising product is birch sap. The market for bottled birch sap in Poland is monotonous, relying exclusively on pasteurized, acidified and sweetened drinks. A chance to change this situation is to develop a birch sap concentrate obtained by reverse osmosis. It has a sweet taste desired by consumers and particularly...
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Synchronization system for underwater acoustic communications using in shallow waters
PublikacjaA reliable synchronization system of the transmitted data frame has a significant impact on the efficiency of the underwater communication system. This applies in particular to communication systems dedicated to work in shallow waters, where the phenomenon of multipath permanently occurs. To overcome these difficulties, the concept of a synchronization system consisting of two broadband signals of opposite monotonicity was presented....
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Ship Dynamic Positioning Based on Nonlinear Model Predictive Control
PublikacjaThe 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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Causes of damage and methods of repairing floor made on polystyrene concrete
PublikacjaThe paper describes damages, tests and repair of the floor made on existing ceiling and expanded polystyrene concrete underlay. The floor was built on a reinforced concrete ceiling with an area of about 1050 m2. Significant damage in the form of cracks, detachments and unevenness was found in the floor. In order to determine the causes of damage, in situ tests and laboratory tests were carried out. It was found that the damage...
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THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THIN-WALLED BEARING SHELL’S DESIGN PARAMETERS AND ASSEMBLY CONDITIONS ON THE HOLDING TORQUE INSIDE A HOUSING BORE OF A CONNECTING ROD
PublikacjaThe aim of the work was the experimental and theoretical evaluation of the influence of the most important parameters determining the holding torque of a thin-walled bearing shell inside a housing bore of a connecting rod. The main investigated parameters were defned by authors experience in this feld. In the frst stage of research, a special test stand was designed in order to allow measuring the real values of the friction torque...
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Reliable testbed for indoor positioning systems
PublikacjaThis paper proposes a test environment for indoor localization system, based on radio wave propagation prosperities. The following sections presents variety of problems from the assessment of the existing localization system to the analysis of inconveniences which occur when comparison of different localization systems is implemented. The problem is associated with different testing environments presented in published papers is...