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Search results for: BOUNDARY LAYER REGENERATION
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Reconstruction of thin films polyazomethine based on microscopic images
PublicationPurpose: The aim of this paper was to investigate changes in surface morphology of thin films ofpolyazomethine PPI. Thin films were prepared using low-temperature chemical vapor deposition (CVD)method.Design/methodology/approach: The changes in surface topography was observed by the atomicforce microscope AFM and scanning electron microscope SEM. The results of roughness have beenprepared in the software WSxM NanoTec Spanish...
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Characteristics of silver-dopped carbon nanotube coating destined for medical applications
PublicationCarbon nanotubes are materials demonstrating outstanding mechanical, chemical, and physical properties and are considered coatings of titanium implants. The present research is aimed to characterize the microstructure and properties of the multi-wall carbon nanotubes (MWCNTs) layer decorated with silver nanoparticles (Ag NPs) on the Ti13Nb13Zr alloy destined for long-term implants. The electrophoretic deposition of coatings...
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Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions
PublicationAg-based plasmonic nanostructures were manufactured by thermal annealing of thin metallic films. Structure and morphology were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). SEM images show that the formation of nanostructures is influenced by the initial layer thickness as well as the...
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A simple route of providing a soft interface for PEDOT: PSS film metallic electrodes without loss of their electrical interface parameters
PublicationThe work presents the development of a soft interface at PEDOT:PSS film without changing its electrical interface parameters. In the first step, PEDOT:PSS is electrodeposited on the commercial platinum electrode under the state-of-the-art conditions desirable for different electrochemical electrodes. Secondly, a pure hydrogel layer is deposited on the top of the electrodeposited PEDOT:PSS film under conditions that provide desirable...
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Seeding enhancement for microcrystaline diamond layers growth on non-diamond substrates
PublicationThe present paper gives an overview on the possible methods of seeding substrates for diamond layers growth. Diamond in reason of his properties is very desirable material in microelectronic, biomedical and waste treatment sensors. Microcrystalline diamond for these applications must be grown on silicon substrate in microwave plasma assisted chemical vapor deposition (MPACVD). To grow diamond on non-diamond surface pre-growth...
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4-Point beam tensile test on a soft adhesive
PublicationAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
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Optical investigations of electrochemical processes using a long-period fiber grating functionalized by indium tin oxide
Publicationhe growing needs for fast and reliable sensing devices stimulate development of new technological solutions. In this work a new multi-domain sensing method is demonstrated where optical sensing device has been applied to enhance amount of data received during electrochemical analysis. Thin, optically transparent, high-refractive-index, and electrically conductive indium tin oxide (ITO) film was deposited using magnetron sputtering...
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INVESTIGATION OF ACIDIC SOLUTIONS BY POTENTIOMETRIC TASTE SENSOR WITH ALL SOLID STATE ELECTRODES
PublicationPotentiometric taste sensors with electrodes containing lipophilic compound / polymer membranes were already used to distinguish commercial liquid products. In this paper a new potentiometric taste sensor consisting of six All Solid State Electrodes (ASSEs) has been presented. Each of the membrane contains a selected lipophilic compound. The set-up consists of a reference electrode and six ASSEs. The inner layer made of a conducting...
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The best porous asphalt pavement in Sweden so far
PublicationIn 2010 a double-layer porous asphalt concrete (DPAC) pavement was constructed in various versions on the E4 motorway through the Swedish city Huskvarna. As a result of a court decision the Swedish Transport Administration had to reduce noise emission by applying a low noise road surface that would reduce A-weighted noise levels by 5 dB, as an average. Earlier experience in Sweden indicated that it was possible to obtain a high...
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Flexible dye-sensitized solar cells based on Ti/TiO2 nanotubes photoanode and Pt-free and TCO-free counter electrode system
PublicationFlexible dye-sensitized solar cells (DSSCs) are getting more attention compared to standard glass covered DSSCs due to their unique commercial applications (e.g. tents or sail surfaces) and the possibility of rolling up into a small, portable device. In this work, titania nanotubes (TiO2 NT) modified with titania nanoparticles (TiO2 NP) were photoelectrochemically characterized as an anode for flexible dye-sensitized solar cells....
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Study on Combined Optical and Electrochemical Analysis Using Indium-tin-oxide-coated Optical Fiber Sensor
PublicationThe growing needs for fast and reliable sensing devices stimulate development of new technological solutions. In this work a new multi-domain sensing method is demonstrated where optical sensing device has been applied to enhance amount of data received during electrochemical analysis. Thin, optically transparent, high-refractive-index, and electrically conductive indium tin oxide (ITO) film was deposited using magnetron sputtering...
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Towards Carbon Neutral Settlements. The Importance of Early-Stage Urban and Energetic Optimizations
PublicationThe aim of the research was to verify the essence of interdisciplinary energy optimizations in earlystage urban design process. A further aim was to the find most optimal design variant and scenario in terms of urban energy efficiency for the future development in Nowy Port, located in Gdansk, Poland - a place requiring complex revitalization. The research combined qualitative and quantitative approaches; an urban design layer...
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Optical Sensor Based Gestures Inference Using Recurrent Neural Network in Mobile Conditions
PublicationIn this paper the implementation of recurrent neural network models for hand gesture recognition on edge devices was performed. The models were trained with 27 hand gestures recorded with the use of a linear optical sensor consisting of 8 photodiodes and 4 LEDs. Different models, trained off-line, were tested in terms of different network topologies (different number of neurons and layers) and different effective sampling frequency...
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Mechanical Properties and Wear Susceptibility Determined by Nanoindentation Technique of Ti13Nb13Zr Titanium Alloy after “Direct Laser Writing”
PublicationLaser treatment has often been applied to rebuild the surface layer of titanium and its alloys destined for long-term implants. Such treatment has always been associated with forming melted and re-solidified thin surface layers. The process parameters of such laser treatment can be different, including the patterning of a surface by so-called direct writing. In this research, pulse laser treatment was performed on the Ti13Nb13Zr...
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Introduction to the ONDM 2022 special issue
PublicationThis JOCN special issue contains extended versions of selected papers presented at the 26th International Conference on Optical Network Design and Modeling (ONDM 2022), which took place 16–19 May 2022 at Warsaw University of Technology, Warsaw, Poland. The topics covered by the papers represent trends in optical networking research: application of machine learning to network management, cross-layer network performance optimization,...
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Billiard in a rotating half-plane
PublicationThe main objective of this research is to study the properties of a billiard system in an unbounded domain with moving boundary. We consider a system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points and experiences elastic collisions with the ball. We define a mathematical model for the dynamics of such a system and write down asymptotic...
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On thermal stability of piezo-flexomagnetic microbeams considering different temperature distributions
PublicationBy relying on the Euler–Bernoulli beam model and energy variational formula, we indicate critical temperature causes in the buckling of piezo-flexomagnetic microscale beams. The corresponding size-dependent approach is underlying as a second strain gradient theory. Small deformations of elastic solids are assessed, and the mathematical discussion is linear. Regardless of the pyromagnetic effects, the thermal loading of the thermal...
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Effects of subfilter velocity modelling on dispersed phase in LES of heated channel flow
PublicationA non-isothermal turbulent flow with the dispersed phase is modelled using the Large Eddy Simulation (LES) approach for fluid, one-way coupled with the equations of point-particle evolution. The channel is heated at both walls and isoflux boundary conditions are applied for fluid. Particle velocity and thermal statistics are computed. Of particular interest are the r.m.s. profiles and the probability density function of particle...
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Influence of anisotropic stiffness in numerical analyses of tunneling and excavation problems in stiff soils
PublicationIn the stiff overconsolidated soil deposits anisotropy influences small and intermediate strain stiffness and hence it has important impact on the results of discplacement preditcions in soil-structure modelling. The authors developed a cross-anisotropic soil model which combines both stress dependent and micro-structural anisotropy. The model is based on the anisotropic hyperelastic kernel for small strain stiffness. Reference...
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Comparative analysis of different numerical models of a steel radial gate
PublicationHydrotechnical structures are important components in water management system and general flooding safety. Their reliability should be ensured since potential damage might lead to catastrophic consequences. Weir gates are considered to be highly vulnerable elements of each hydro power plant, with regard to its dynamic resistance. The aim of the paper is to compare different numerical models and their influence on the results of...
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Numerical assessment of ultimate strength of severe corroded stiffened plates
PublicationThe objective of this work is to investigate numerically (using the non-linear FEM and the approach stipulated by the Common Structural Rules) the severe nonuniform corrosion degradation effect on the ultimate strength of stiffened plates and compare the results to the already published experimental works. Different factors governing structural behavior of corroded stiffened plates are investigated, such as corrosion degradation level,...
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Minimal parameter implicit solvent model for ab initioelectronic-structure calculations
PublicationAbstract - We present an implicit solvent model for ab initio electronic-structure calculations which is fully self-consistent and is based on direct solution of the nonhomogeneous Poisson equation. The solute cavity is naturally defined in terms of an isosurface of the electronic density according to the formula of Fattebert and Gygi (J. Comput. Chem., 23 (2002) 662). While this model depends on only two parameters, we demonstrate...
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Mathematical model of pennate muscle
PublicationThe purpose of this study is to create a new mathematical model of pennate striated skeletal muscle. This new model describes behaviour of isolated flat pennate muscle in two dimensions (2D) by taking into account that rheological properties of muscle fibres depend on their planar arrangement. A new mathematical model is implemented in two types: 1) numerical model of unipennate muscle (unipennate model); 2) numerical model of...
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Dynamic soil improvement by hybrid technologies
PublicationHybrid method of subsoil improvement for road embankment foundation is described. This method is composed of two wellknown methods: dynamic replacement (DR) and microblasting (DDC) one (Deep Dynamic Compaction). The method was used for both the strengthening of the fully saturated organic subsoil as well as for acceleration of the consolidation of the organic layers. The practice ensures the expected results. A proper example on...
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IDENTIFICATION OF THE INTERFECE OF LATERAL SLIDE BEARINGS
PublicationIn the paper, the model of slide bearings of motor engine, the metodology of research on this type of bearings and its results are presented measurement standpoint consisting of main elements of Briggs & Stratton 550 serie 10 T 802 model piston motor engine driven by three phase elektric engine is introduced . On the measurement standpoint are measurements were done, needed for specification...
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Rotor Blade Geometry Optimisation in Kaplan Turbine
PublicationThe paper presents the description of method and results of rotor blade shape optimisation. The rotor blading constitutes a part ofturbine flow path. Optimisation consists in selection of the shape that minimises ratio of polytrophic loss. Shape of the blade isdefined by the mean camber line and thickness of the airfoil. Thickness is distributed around the camber line based on the ratio ofdistribution. Global optimisation was done...
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On a comparison principle and the uniqueness of spectral flow
PublicationThe spectral flow is a well-known quantity in spectral theory that measures the variation of spectra about 0 along paths of selfadjoint Fredholm operators. The aim of this work is twofold. Firstly, we consider homotopy invariance properties of the spectral flow and establish a simple formula which comprises its classical homotopy invariance and yields a comparison theorem for the spectral flow under compact perturbations. We apply...
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Under the Fire of Disinformation. Attitudes Towards Fake News in the Ukrainian Frozen War
PublicationIn this article, we examine individual attitudes towards fake news in the extreme conditions of a propaganda war, taking into account the complex regional social and historical conditions. For this purpose, within the mobile boundary zone during frozen war in Ukraine, we conducted qualitative research among representatives of generations X and Z (high school teachers and students). Being accustomed to fake news turned out to be...
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Bending and buckling formulation of graphene sheets based on nonlocal simple first-order shear deformation theory
PublicationThis paper presents a formulation based on simple first-order shear deformation theory (S-FSDT) for large deflection and buckling of orthotropic single-layered graphene sheets (SLGSs). The S-FSDT has many advantages compared to the classical plate theory (CPT) and conventional FSDT such as needless of shear correction factor, containing less number of unknowns than the existing FSDT and strong similarities with the CPT. Governing...
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On the plastic buckling of curved carbon nanotubes
PublicationThis research, for the first time, predicts theoretically static stability response of a curved carbon nanotube (CCNT) under an elastoplastic behavior with several boundary conditions. The CCNT is exposed to axial compressive loads. The equilibrium equations are extracted regarding the Euler–Bernoulli displacement field by means of the principle of minimizing total potential energy. The elastoplastic stress-strain is concerned...
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Review of the Application of Graphene-Based Coatings as Anticorrosion Layers
PublicationDue to the excellent properties of graphene, including flexibility that allows it to adjust to the curvature of the substrate surface, chemical inertness, and impermeability, graphene is used as an anticorrosion layer. In this review, we present the current state-of-the-art in the application of graphene in the field of protective coatings. This review provides detailed discussions about the protective properties of graphene coatings...
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Hybrid biobateryy based on arylated carbon nanotubes and laccase
PublicationSingle-walled carbon nanotubes (SWCNT) were covalently modified with antracene and antraquinone and used for the construction of cathodes for biocatalytic reduction od dioxygen. The nanotubes with aromatic groups casted onto the electrode increased the working surface of the electrode and enabled efficient direct electron tarnsfer (DET) between the enzyme and the electrode. the aryl groups enter the hydrophobic pocket of the T1...
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Large Hydrodynamic Thrust Bearings and Their Application in Hydrogenerators
PublicationLarge hydrodynamic thrust bearings are the bearings which, due to hydrodynamic lubrication, allow large axial load to be transferred from a moving part (shaft) to the stationary part via a thin layer of the lubricant (usually oil), thus providing extremely low friction and practically no wear. Hydrogenerators with vertical shafts are the most important application of large thrust bearings. Main design and scientific problems of...
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Path Loss Modelling for Location Service Applications
PublicationThe aim of this paper is the path loss modeling for the radiolocation services in radiocommunication networks, particularly in cellular networks. The main results of the measurements obtained in the physical layer of the UMTS are introduced. A new method for the utilization of the multipath propagation phenomenon to improve the estimation of the distance between the mobile station (MS) and the base station (BS) is outlined. This...
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Comparative study of neural networks used in modeling and control of dynamic systems
PublicationIn this paper, a diagonal recurrent neural network that contains two recurrent weights in the hidden layer is proposed for the designing of a synchronous generator control system. To demonstrate the superiority of the proposed neural network, a comparative study of performances, with two other neural network (1_DRNN) and the proposed second-order diagonal recurrent neural network (2_DRNN). Moreover, to confirm the superiority...
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The properties of reduced Ge-Sb-O glasses for thermoelectric devices
PublicationThe structural and electrical properties of germanium-antimonate glasses after heat treatment in hydrogen have been determined. In the case of 50GeO2-50Sb2O3 glass reduced at 340°C even for less than 1 hour a continuous layer of antimony granules is formed and its electrical properties determine the surface conductivity of the reduced sample. The bulk electrical conductivity at 100°C of this sample was determined as 1000 Scm-1...
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Synthesis and Testing of BCZY/LNZ Mixed Proton–electron Conducting Composites for Fuel Cell Applications
PublicationA composite of BaCe0.6Zr0.2Y0.2O3–δ and Li2O:NiO:ZnO was investigated for fuel cell applications. The composite was successfully synthesized and its phase stability was confirmed at temperatures up to 900 °C. The influence of sintering and pressing aids on density was also investigated. Electrical properties were measured. DC electrical conductivity was about 8•10-4 S/m at 845 K. Open circuit voltage measurements in wet hydrogen...
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Harmony Search to Self-Configuration of Fault-Tolerant Grids for Big Data
PublicationIn this paper, harmony search algorithms have been proposed to self-configuration of fault-tolerant grids for big data processing. Some tasks related to big data processing have been considered. Moreover, two criteria have been applied to evaluate quality of grids. The first criterion is a probability that all tasks meet their deadlines and the second one is grid reliability. Furthermore, some intelligent agents based on harmony...
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Topology Discovery of Hierarchical Ethernet LANs without SNMP support
PublicationThis paper presents an algorithm that allows for discovery of layer-2 hierarchical Ethernet network topology using agents running on selected end nodes. No SNMP, MIB, hardware, firmware, or operating system-level software modification is required. The method is based on transmission of customized Ethernet frames among installed software agents. It can be used to discover the topology of LAN or one VLAN segment as long as no MAC...
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Failure analysis of the exhaust valve face in diesel marine engine
PublicationThe exhaust valve from marine diesel engine which was damaged after 2000 hours of service was investigated. In order to prolong the service time the valve face was cladded with cobalt base alloy using laser technique. After failure microstructural and chemical analyses reviled that cladding process was conducted improperly. The chemical composition of the clad layer was far from the designed one and what more completely inhomogeneous....
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Development of beltless respiration and heartbeat sensor based on flexible piezoelectric film
PublicationThe main goal of this work is to report initial development on a respiration and heartbeat measurement sensor that can be used in continuous monitoring conditions at a minimal impact on the patient. General description of the sensor, consisting of a PVDF film and the bonding layer, is given. Open-circuit voltage generated by the sensor is estimated by analytical and numerical calculations. Analog and digital interface used to extract...
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The Quantum Efficiency Roll-Off Effect in Near-Infrared Organic Electroluminescent Devices with Iridium Complexes Emitters
PublicationThe electroluminescence quantum efficiency roll-off in iridium(III)-based complexes, namely Ir(iqbt)2(dpm) and Ir(iqbt)3(iqbt=1 (benzo[b]thiophen-2-yl)-isoquinolinate, dpm=2,2,6,6-tetramethyl-3,5-heptanedionate) utilized as near-infrared emitters in organic light emitting diodes with remarkable external quantum efficiencies, up to circa 3%, 1.5% and 1%, are measured and analyzed. With a 5–6 weight % of emitters embedded...
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X-Ray Computer Tomography Study of Degradation of the Zircaloy-2 Tubes Oxidized at High Temperatures
PublicationThe investigations of high-temperature oxidation of zirconium alloys, applied for fuel pellets in nuclear power plants, are usually limited to oxidation kinetics, phase transformations and microstructural characterization. The purpose of this research was to characterize the degradation phenomena occurring within oxide layer and at the interface oxide/metal, on internal and external Zircaloy-2 tube...
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Evaluation of citric acid corrosion inhibition efficiency and passivation kinetics for aluminium alloys in alkaline media by means of dynamic impedance monitoring
PublicationA novel approach is proposed for constructing the adsorption isotherm in corrosion studies, based on a well-known interaction between citric acid and aluminium in alkaline electrolytes. Our approach utilizes the instantaneous impedance measurements via Dynamic Electrochemical Impedance Spectroscopy in galvanostatic mode (g-DEIS). Unlike other common tools, g-DEIS delivers exact information about the concentration required for full...
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Zirconia-based mixed potential sensor with Pt electrode prepared by spin-coating of polymeric precursor
PublicationMany types of yttria-stabilized zirconia (YSZ) based gas sensors have been explored extensively in recent years. Great attention have been directed to mixed-potential-type gas sensors. It is due to growing concerns with environmental issues. Not without a significance is the fact of very attractive performance of this type of sensor allowing to detect low concentration of pollutant gases. In this paper two types of YSZ based mixed-potential...
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Nested Space Mapping Technique for Design and Optimization of Complex Microwave Structures with Enhanced Functionality
PublicationIn this work, we discuss a robust simulation-driven methodology for rapid and reliable design of complex microwave/RF circuits with enhanced functionality. Our approach exploits nested space mapping (NSM) technology, which is dedicated to expedite simulation-driven design optimization of computationally demanding microwave structures with complex topologies. The enhanced func-tionality of the developed circuits is achieved by means...
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The analysis of the influence of the corrosion protection method of selected steel elements on the steel structure life cycle costs
PublicationSteel products are widely used in the construction for the performance of essential and additional elements of engineering structures. They are characterized by high tensile strength, compression and bending, the structure homogeneity, the possibility of assembly regardless of the season and climatic conditions, ease of processing and the possibility of almost any shape. The main disadvantage of steel structures is their high susceptibility...
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Comparison of Properties of the Hybrid and Bilayer MWCNTs—Hydroxyapatite Coatings on Ti Alloy
PublicationCarbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different...
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High-performance NdSrCo2O5+δ–Ce0.8Gd0.2O2-δ composite cathodes for electrolyte-supported microtubular solid oxide fuel cells
PublicationNdSrCo2O5+δ (NSCO) is a perovskite with an electrical conductivity of 1551.3 S cm−1 at 500 °C and 921.7 S cm−1 at 800 °C and has a metal-like temperature dependence. This perovskite is used as the cathode material for Ce0.8Gd0.2O2-δ (GDC)-supported microtubular solid oxide fuel cells (MT-SOFCs). The MT-SOFCs fabricated in this study consist of a bilayer anode, comprising a NiO–GDC composite layer and a NiO layer, and a NSCO–GDC...
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Effect of Nanohydroxyapatite on Silk Fibroin–Chitosan Interactions—Molecular Dynamics Study
PublicationFibroin–chitosan composites, especially those containing nanohydroxyapatite, show potential for bone tissue regeneration. The physicochemical properties of these biocomposites depend on the compatibility between their components. In this study, the intermolecular interactions of fibroin and chitosan were analyzed using a molecular dynamics approach. Two types of systems were investigated: one containing acetic acid and the other...