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Dynamic mechanical properties and flexing fatigue resistance of tire sidewall rubber as function of waste tire rubber reclaiming degree
PublikacjaA stepwise downsizing method of gel particles in reclaimed rubber to a micro-nano scale and its excellent dynamic performance in tire sidewall were introduced by this work. The results showed that the size of gel particles decreased from several micrometers to micro-nanometers with the increase of reclaiming degree, accompanied by reduced molecular weight and widened molecular weight distribution of sol fraction. The addition of...
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A comparative performance assessment of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
PublikacjaThis work presents the investigation results of a journal bearing lubricated with magnetorheological fluid that is activated by a local constant magnetic field to vary both the local flow resistance and pressure. The bearing performance is assessed via Finite Element Modelling (FEM) and results are corroborated by experiments. The FEM model uses the Bingham model to describe the fluid film. A dedicated test rig is used to assess...
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A pin-on-disc study of airborne wear particle emissions from studded tyre on concrete road contacts
PublikacjaStudded tyres wear surfaces of winter roads, generating inhalable airborne particles. In this study, four concrete road materials and two stud geometries were investigated in terms of wear, road material hardness and airborne particle concentration. The sliding contact between studded tyres and road materials was studied using a pin-on-disc machine in a clean chamber. The results show that the normal load and the stud size have...
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Reliability Analysis of Sea Cliff Slope Stability by Point Estimate Method
PublikacjaThe paper presents a reliability analysis of a sea cliff slope. The cliff, located in Jastrzębia Góra, is characterised by a complicated geological structure. Although currently stable, it is in fact close to the limit state. The objective of this paper is to present the point estimate method (PEM) of determining the mean value and standard deviation of the safety factor of the slope. Assuming its normal distribution, these statistical...
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Synergistic effect of multi walled carbon nanotubes and reduced graphene oxides in natural rubber for sensing application
PublikacjaUtilizing the electrical properties of polymer nanocomposites is an important strategy to develop high performance solvent sensors. Here we report the synergistic effect of multi walled carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) in regulating the sensitivity of the naturally occurring elastomer, natural rubber (NR). Composites were fabricated by dispersing CNTs alone and together with exfoliated RGO sheets (thermally...
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Effect of microstructure on mechanical properties of BA1055 bronze castings
PublikacjaThe article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1032) castings used for marine propellers. Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich phase precipitates in bronze microstructure significantly affect its mechanical...
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Performance Analysis of the "Intelligent" Kirchhoff- Law - Johnson-Noise Secure Key Exchange
PublikacjaThe Kirchhoff-law - Johnson-noise (KLJN) secure key distribution system provides a way of exchanging theoretically secure keys by measuring random voltage and current through the wire connecting two different resistors at Alice’s and Bob’s ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper, we analyze the KLJN system and compare with the „intelligent” KLJN (iKLJN)...
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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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Nonlinear viscoelasticity in Three Dimensional filler reinforced rubber composites and nanocomposites
PublikacjaThis 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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Treatment Wetland for Overflow Stormwater Treatment: The Impact of Pollutant Particles Size
PublikacjaThe problem of stormwater treatment in urban areas has become increas- ingly crucial. It has been widely recognized that both mechanical and biological treatment of stormwater is necessary to protect surface water against pollution. Moreover, technology must be applied to ensure effective treatment in changing hydraulic conditions and to serve, to the extent possible, as a retention volume. Treatment wetland (TW) could be...
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Multiple access in ad-hoc wireless LANs with noncooperative stations
PublikacjaA class of contention-type MAC protocols (e.g., CSMA/CA) relies on random deferment of packet transmission, and subsumes a deferment selection strategy and a scheduling policy that determines the winner of each contention cycle. This paper examines contention-type protocols in a noncooperative an ad-hoc wireless LAN setting, where a number of stations self-optimise their strategies to obtain a more-than-fair bandwidth share. Two...
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FE analysis of a coupled energetic-statistical size effect in plain concrete beams with varying material properties.
PublikacjaThe numerical FE investigations of a coupled energetic-statistical size effect in unnotched concrete beams of similar geometry under quasi-static three point bending were performed within elasto-plasticity with non-local softening. The stochastic FE analyses were carried out with three different beam sizes. Deterministic calculations were performed with the uniform distribution of a uniaxial tensile strength. In statistical calculations...
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Spatio-Temporal Validation of GNSS-Derived Global Ionosphere Maps Using 16 Years of Jason Satellites Observations
PublikacjaExisting ionospheric models perform very well in mapping the calm state of the ionosphere. However, the problem is accurately determining the total electron content (TEC) for disturbed days. Knowledge of the exact electron density is essential for single−frequency receivers, which cannot eliminate the ionospheric delay. This study aims to investigate temporal and spatial variability in the distribution of TEC based on differences...
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SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NIOBIUM-DOPED HYDROXYAPATITE CERAMICS
PublikacjaHydroxyapatite (HAp) ceramic materials are considered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important...
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Pile Model Tests Using Strain Gauge Technology
PublikacjaOrdinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine...
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Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation
PublikacjaOne of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW...
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Rozdział mocy w układzie napędowym robota podwodnego - porównanie algorytmów alokacji naporów
PublikacjaPraca dotyczy syntezy systemu automatycznego sterowania robotem podwodnym w zakresie problemu rozdziału mocy w wielopędnikowym układzie napędowym. Do alokacji naporów zastosowano metody optymalizacji z ograniczeniami, pozwalające na wyznaczanie wektora naporów na podstawie wektora sił uogólnionych. Rozważono i porównano dwie metody rozdziału mocy dla robota realizującego ruch poziomy płaski o trzech stopniach swobody, rozpatrując...
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Surface Science - 2023/2024
Kursy OnlineThe course is not a full time lecture but on the consultation/handouts. The consulations are held every two weeks. The course is based on the Springer textbook: Surface Science An Introduction Downloadable at: https://link.springer.com/book/10.1007/978-3-662-05179-5 (PG network or vpn access) The goal of the subject is the presentation of basic problems resulting from he existence of interfacebetween material objects...
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A material model of asphalt mixtures based on Monte Carlo simulations
PublikacjaThe paper aims to numerically reflect mineral-asphalt mixture structure by a standard FEM software. Laboratory test results are presented due to bending tests of circular notched elements. The result scatter is relatively high. An attempt was made to form a random aggregate distribution in order to obtain various results corresponding to laboratory tests. The material structure calibration, its homogenization and finite element...
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Depolarisation Model for a BAN Indoor Scenario
PublikacjaIn this paper, an analysis of depolarisation in Body Area Networks for Body-to-Infrastructure communications based on a measurement campaign in the 5.8 GHz band in an indoor environment is performed. Measurements were made with an offbody antenna transmitting linearly polarised signals and dualpolarised receiving antennas carried by the user on the body. A Normal Distribution with a mean of 2.0 dB and a standard deviation of 4.3...
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An influence of the ship's block coefficient implementation on the evaluation of it's hull girder bending
PublikacjaAn influence of the three different ways of implementation ship's block coefficient δ (three geometrical models) on the stresses due to wave bending moment have been investigated. Two models have been applied and compared: beam one (description of the shape usingparameters) and FEM shell model (direct representation of the shape). The outcomes have been compared to Polish Register of Shipping (PRS) rules. The results show that...
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MODEL OF MULTILEVEL STOCHASTIC ANALYSIS OF ROAD SAFETY ON REGIONAL LEVEL
PublikacjaIn this paper multilevel approach to the issue of road safety level on the road network of European regions, classified as NUTS 2 in statistical databases of the European Union, has been presented. Following the pattern of many publications on road safety it has been assumed that the risk calculated as the number of death casualties in road accidents per 100,000 inhabitants of a given region has Poisson distribution. Therefore,...
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Rain Water: Atmospheric Deposition
PublikacjaWater is transferred from the atmosphere to the land surface mainly via various forms of atmospheric precipitation; however, the contribution of surface condensation/deposition (e.g., dew, hoar frost, occult precipitation) should not be neglected. Rainwater and liquid deposits (dew, hoar frost, rime) are components of the physical and geographical environment that are easily assimilated and transported. Thus, they are generally...
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Shell model of multiple-row moment I-section end-plate joint
PublikacjaThe paper deals with a problem of application of shell elements in the models of multiple-row moment end-plate connections. The extended connection of I-section with a cross-section W760x265x220 made of steel S355 was analyzed. Comparison analysis of FEM, complex volume and shell models has been done. Three cases with different end-plate thickness: 14, 18 and 36 mm were analyzed and compared with the reference results. Comparison...
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Optimization of chip removing system operation in circular sawing machine
PublikacjaThe paper presents the optimization of the wood chips removing system in the sliding table saw. Chips are generated during the cutting of the material. The attention was focused on the upper casing of mentioned system. The methodical experimental studies of the pressure distribution inside the casing during the wood chip removing operation for the selected rotational speed of saw blade with a diameter of 300 mm and 450 mm were...
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Influence of drying mode and feed per tooth rate on the fine dust creation in pine and beech sawing on a mini sash gang saw
PublikacjaThe experimental results of the study focused on the effect of drying processes of modified air drying and warm air steam mixture drying of pine and beech wood on the size of sawdust particles created in cutting using PRW-15M sash gang saw, are presented in the paper. Particle size analysis of dry sawdust was performed using two methods—sieving method and laser diffraction analysis. The results showed that the drying process did...
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NUMERICAL MODELLING AND EXPERIMENTATION OF HISTORICAL CARPENTRY CORNER LOG JOINTS
PublikacjaThe main purpose of this research is to determine the stress distributions on the contact surfaces between the logs of the historical carpentry corner joints. The additional purpose is to compare the stress distribution for four different boundary conditions in the case of dry and wet pine wood. The paper presents the results of numerical analysis of the shortcorner dovetail connection and the saddle notch corner joint, which are...
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E-textbook technologies for academics in medical education
PublikacjaPublic universities in Poland receive fairly limited financial support for creating e-textbooks and lack the appropriate ICT competences among teaching staff, especially in the case of non-technical universities. The authors propose a pedagogical and technological paradigm for e-textbooks in medical education using open source software with minimal IT skills required. Technologies used to develop e-textbooks are connected with:...
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Calculations of labyrinth seals with and without diagnostic extraction in fluid-flow machines
PublikacjaLabyrinth seals are essential components of steam turbine unit constructions. Two types of labyrinth seals can be named, the first of which is the seal without diagnostic steam extraction, and the second – with extraction. The distribution of flow parameters along the packing is affected remarkably by the average seal clearance. The presence of diagnostic extraction leads to the equation system which is determinable and can be...
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Sound Field Intensity Measurements and Visualization around the Human Head Model . Rozkłąd natężenia pola akustycznego w komorze bezechowej obecności sztucznej głowy i w przypadku braku jej obecności
PublikacjaThe main goal of this research study was to measure and visualize sound field intensity distribution in and without presence of the human head model. Measurements were performed in the anechoic chamber with the 5 cm grid. Experimental setup consisted of a multitone generator, two loudspeakers, human head model, intensimetric probe, the Cartesian robot applied for precise positioning of the acoustic sensor, and an analyzer. Based...
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The use of Markov chains in the social convergence analysis
PublikacjaThe main goal of this article is to analyze the social convergence process using Markov chains. In this research, term social convergence refers to the reduction of dispersion in the standard of living among countries. The use of Markov chains in the social convergence analysis allowed describing movements of observational units within the distribution and providing more details about the mechanism of the convergence process. A...
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On the correlation between magnetoacoustic emission and magnetostriction dependence on the applied magnetic field
PublikacjaThe correlation between magnetoacoustic emission signal envelopes and magnetostriction curves is investigated. Two sets of samples are being considered: tempered martensitic steel and plastically deformed ferritic steel. It is shown that even though some general relations may be observed, as was demonstrated in the literature, the correlation is not always present. One may not expect to change both quantities in the same way if...
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Mesoscopic simulations of crack propagation in concrete using cohesive elements
PublikacjaThe paper presents results of two-and three-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 3-phase material composed of aggregate grains placed in the cement matrix with Interfacial Transitional Zones (ITZs) between then. In 2D simulations macro-voids were also taken into account. The particle distribution was taken from real concrete beams...
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Analiza doświadczalna wpływu długości zakotwienia pręta na zachowanie przyczepności w teście pull-out
PublikacjaArtykuł prezentuje badania przyczepności przeprowadzone przy użyciu testu pull-out. Eksperymenty miały na celu ocenę wpływu długości zakotwienia na przyczepność w tym teście. Z przeprowadzonej analizy wynika, że długość styku pręt-beton znacząco wpływa na zachowanie przyczepności. Określa ona typ zniszczenia połączenia, wpływa na rozkład i wartość naprężeń w pręcie oraz rzutuje na przebieg krzywej przyczepność-poślizg, która jest...
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Natural ventilation performance of family building in cold climate during windy days
PublikacjaAdequately designed natural ventilation is the cheapest and easiest way to effectively remove indoor pollutants and keep the fresh air inside a building. A prediction of performance and effectiveness of ventilation in order to determine the design of a ventilation system can provide real and long term cost savings. The paper presents results of performance (air change rate ACH) and effectiveness (CO2 concentration in the breathing...
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Assessment of Alterations in Settlement Patterns of Agricultural Landscape in the Example of Kashubia in Poland
PublikacjaTraditional agricultural landscapes are heavily exposed to change due to their relatively low agricultural productivity. However, they represent cultural values of great importance in maintaining the resilience of the environment and society. Although their cultural potential is important for sustainable development, it is still insufficiently recognized. The article fills this gap by examining old farmstead buildings as a distinguishing...
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Global value chains, wages, employment and labour production in China: A regional approach
PublikacjaIn this study we analyse the relationship of trade and global value chains (GVCs) to the labour market in 31 Chinese provinces for 25 sectors, by means of a system of structural equations. We firstly distinguish between provincial value chains (PVCs) and interprovincial value chains (PRVCs) in order to outline their distribution and evolution over time. Then, we investigate to what extent participation in GVCs, PVCs and PRVCs –...
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Stability Investigation of the PCM Nanocomposites
PublikacjaEnsuring the stability is a key issue to be solved for the technical application of nanocomposites. In this work, fatty acid P1801 served as base phase change material (PCM)P1801, and its main ingredients are palmitic acid (58%) and stearic acid (38%). Titania (TiO2) and alumina (Al2O3) with mass concentrations of 1% and 5% were selected as nanoparticles, while polyvinylpyrrolidone (PVP) or oleic acid (OA) with mass concentrations...
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Corrosion degradation monitoring of ship stiffened plates using guided wave phase velocity and constrained convex optimization method
PublikacjaThe study presents an experimental investigation on the corrosion degradation level assessment using nondestructive wave-based methods. The degradation level of ship structural elements has been assessed in two different ways. The first one is based on the spectral decomposition and zero-crossing incorporated reconstruction of the dispersion curve approach of the antisymmetric Lamb wave mode and the best matching of the theoretical...
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Computational Fluid Dynamics Simulation of Gas–Liquid Multiphase Flow in T-junction for CO2 Separation
PublikacjaThe article presents the results of a computational fluid dynamics (CFD) analysis of gas-liquid multiphase flow. The simulation was conducted using CFD code and the Euler–Euler approach. The presented study relates to the non–reactive, steady-state, turbulent flow of water and carbon dioxide mixture in a 3D pipe. Separation phenomenon between phases is observed. The solution was obtained using a mixture model. Different values...
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Technical fabrics in costruction of large scale roofs - numerical and experimental aspects
PublikacjaDesigning and construction of textile hanging roofs is the challenging subject for engineers. This type of structure needs geometrically and very often also physically non-linear calculations. Due to different behaviour of two families of threads (warp and weft), which during deformation can change the angle between their directions, they require special constitutive modelling. Also the loading of hanging roofs is very special....
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Optimising approach to designing kernel PCA model for diagnosis purposes with and without a priori known data reflecting faulty states
PublikacjaFault detection plays an important role in advanced control of complex dynamic systems since precise information about system condition enables efficient control. Data driven methods of fault detection give the chance to monitor the plant state purely based on gathered measurements. However, they especially nonlinear, still suffer from a lack of efficient and effective learning methods. In this paper we propose the two stages learning...
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Influence of a Radio Frequency on RF Fingerprinting Accuracy Based on Ray Tracing Simulation
PublikacjaIn this paper the influence of a radio signal frequency on performance of Indoor Positioning System based on fingerprinting has been examined using ray-tracing simulations. It has been simulated how spatial distribution of an RF signal strength change with the signal’s frequency. The results were used to show its’ impact on the behavior of localization algorithms that are employing RSS measurements to determine node’s position...
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HYDROACOUSTIC NOISE MEASUREMENTS
PublikacjaThe paper deals mainly with investigation of underwater noise that propagation is in shallow water. In this paper has been presented the experimental investigation results concerning the distribution of the sound field pressure generated by moving ships in the shallow water at the small distance from the ship. The main acoustical characteristics describing features of the field are spectrograms in pseudo 3D system – distance and frequency...
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Influence of pitting corrosion on fatigue and corrosion fatigue of ship and offshore structures. Part II: Load - pit crack interaction
PublikacjaIn the paper has been discussed influence of stresses on general corrosion rate and corrosion pit nucleation and growth rate, whose presence has been questioned by some authors but accepted by most of them. Influence of pit walls roughness on fatigue life of a plate suffering pit corrosion and presence of so called "non damaging" pits which never lead to initiation of fatigue crack, has been presented. Possibility of prediction...
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Central-force decomposition of spline-based modified embedded atom method potential
PublikacjaCentral-force decompositions are fundamental to the calculation of stress fields in atomic systems by means of Hardy stress. We derive expressions for a central-force decomposition of the spline-based modified embedded atom method (s-MEAM) potential. The expressions are subsequently simplified to a form that can be readily used in molecular-dynamics simulations, enabling the calculation of the spatial distribution of stress in...
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Ultrasonic-assisted Electrodeposition of Cu-Sn-TiO2 Nanocomposite Coatings with Enhanced Antibacterial Activity
PublikacjaCopper-based coatings are known for their high antibacterial activity. In this study, nanocomposite Cu–Sn–TiO2 coatings were obtained by electrodeposition from an oxalic acid bath additionally containing 4 g/dm3 TiO2 with mechanical and ultrasonic agitation. Ultrasound treatment was performed at 26 kHz frequency and 32 W/dm3 power. The influence of agitation mode and the current load on the inclusion and distribution of the TiO2...
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Assessment of User Mobility’s Influence on System Loss in Several Body-to-Body Scenarios
PublikacjaIn this paper, Body-to-Body communications in indoor and outdoor environments for different on-body antenna configurations and different mobility scenarios were studied, based on system loss measurements at 2.45 GHz. The main objective is to properly characterise the influence of the Transmitter-Receiver configuration on system loss and fast fading behaviour, the latter being modelled by the Rice Distribution. Globally, it is observed...
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Effect of heat treatment on the diffusion intermixing and structure of the Cu thin film on Si (111) substrate: a molecular dynamics simulation study
PublikacjaThis work is devoted to the study of the diffusion process at the interface between copper films with a thickness of 2, 3, 4, 7 and 10 atomic monolayers and silicon substrate by molecular dynamics simulation method. For this purpose, the variation of the concentration of copper and silicon along the perpendicular direction to the interface was investigated. An analysis of the density profile along this direction made it possible...
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Spatial Evolution of the European Container Ports’ System in Perspective of the Location Theory
PublikacjaThe maritime container terminal is nowadays a spatially incoherent object. From the functional point of view it ends, where their most external components are located. The process of location splitting of container terminals is a new phase of their discrete growth. The external container facilities are being built to improve effectivness of the logistic chain in the hinterland. The new components of container terminals have very...