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Wyniki wyszukiwania dla: DIFFERENTIAL SCANNING CALORIMETRY
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Spray deposited carbon nanotubes counter electrodes for dye-sensitized solar cells
PublikacjaCarbon nanotubes due to their catalytic properties are a promising alternative to platinum counter electrodes (CE) for dye-sensitized solar cells (DSSC). In this study, counter electrodes were made from double-walled carbon nanotube (DWCNT) ink using the spray printing technique and afterwards thermally treated at temperatures ranging from 120 to 300 °C. Morphology and structure was studied using scanning electron microscopy and...
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Optimization of Graphene Oxide Synthesis and Its Reduction
PublikacjaIn this article, we present the review of the chemical methods of synthesis of graphene oxide and its reduction in order to obtain the so-called reduced graphene oxide (rGO) whose properties are similar to those of pure graphene. We also present our experiments and the results in this field and the comparison of the efficiency of different methods of synthesis as well as the reduction of graphene oxide. To characterize the obtained...
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The effect of elevated temperature on LCF damage growth in 2024AA – Experiment and modeling
PublikacjaThis paper presents the results of experimental low-cycle fatigue (LCF) tests conducted on EN-AW 2024 alloy in T3511 temper at 100 ◦C, 200 ◦C and 300 ◦C. The material’s basic fatigue characteristics were determined, such as fatigue life curve and cyclic strain curve. Both the hysteresis loop and nature of fracture surfaces obtained in macro- and microscopic observations (scanning electron microscope, SEM) were accounted for. The...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublikacjaThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Integration of protein tethering in a rapid and label-free SERS screening platform for drugs of abuse
PublikacjaSurface enhanced Raman spectroscopy (SERS) has emerged as a promising technique for the rapid and ultrasensitive detection of molecular species such as drugs of abuse in biofluids. Yet, it remains a significant challenge to create a viable screening tool for multiple drug classes, owing to the lack of affinity of certain species for the SERS substrate and to the matrix interference in complex media. Here we report a protein tethering...
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Monitoring of Chlorine Concentration in Drinking Water Distribution Systems Using an Interval Estimator
PublikacjaThis paper describes the design of an interval observer for the estimation of unmeasured quality state variables in drinking water distribution systems. The estimator utilizes a set bounded model of uncertainty to produce robust interval bounds on the estimated state variables of the water quality. The bounds are generated by solving two differential equations. Hence the numerical efficiency is sufficient for on-line monitoring...
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Thermal visualization of Ostwald-de Waele liquid in wavy trapezoidal cavity: Effect of undulation and amplitude
PublikacjaThe present study is concerned with the numerical simulations of Ostwald-de Waele fluid flow in a wavy trapezoidal cavity in the presence of a heated cylinder situated at the center of the cavity. The work consists in characterizing the mixed convection as a function of the intensity of heat flow. The flow behaviour and temperature distribution in a cavity are the main focus of this study. The lower wall of the cavity is fixed...
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Effect of surface on the flexomagnetic response of ferroic composite nanostructures; nonlinear bending analysis
PublikacjaOur analysis incorporates the geometrically nonlinear bending of the Euler-Bernoulli ferromagnetic nanobeam accounting for a size-dependent model through assuming surface effects. In the framework of the flexomagnetic phenomenon, the large deflections are investigated referring to von-Kármán nonlinearity. Employing the nonlocal effects of stress coupled to the gradient of strain generates a scale-dependent Hookean stress-strain...
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Balance errors generated by numerical diffusion in the solution of non-linear open channel flow equations
PublikacjaThe paper concerns the untypical aspect of application of the dissipative numerical methods to solve nonlinear hyperbolic partial differential equations used in open channel hydraulics. It is shown that in some cases the numerical diffusion generated by the applied method of solution produces not only inaccurate solution but as well as a balance error. This error may occur even for an equation written in the conservative form not...
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Acoustic heating produced in resonators filled by a newtonian fluid
PublikacjaAcoustic heating in resonators is studied. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. This equation is instantaneous and includes nonlinear acoustic terms that form a...
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Active Kriging-based conjugate first-order reliability method for highly efficient structural reliability analysis using resample strategy
PublikacjaEfficient structural reliability analysis method is crucial to solving reliability analysis of complex structural problems. High-computational cost and low-failure probability problems greatly limit the efficiency in structural reliability analysis problems, causing the safety and reliability of the structure to be questioned. In this work, a highly efficient structural reliability analysis method coupling active Kriging algorithm...
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Tunable emission and energy transfer of B2O3–Bi2O3–AlF3 glass system doped with Eu3+/Dy3+
PublikacjaThe structure and luminescent properties of the B2O3–Bi2O–AlF3 glass system doped with Eu3+/Dy3+ ions in different molar ratios were studied. A series of glasses were synthesized by the conventional melt quenching technique. Glass transition and crystallization temperatures were examined by Differential Thermal Analysis (DTA) measurements. The amorphous character of the prepared samples was confirmed by the X-ray diffraction (XRD)...
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An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
PublikacjaThis work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface...
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Projekt badawczy BRIK: Opracowanie innowacyjnej metody wyznaczania precyzyjnej trajektorii pojazdu szynowego
PublikacjaW artykule przedstawiono podstawowe informacje dotyczące projektu badawczego realizowanego na zlecenie Narodowego Centrum Badań i Rozwoju oraz Spółki PKP Polskie Linie Kolejowe S. A. przez Konsorcjum Politechniki Gdańskiej i Uniwersytetu Morskiego w Gdyni. Projekt obejmuje wykorzystanie nowoczesnych metod pomiarowych, takich jak techniki pozycjonowania satelitarnego GNSS, pomiary inercyjne INS oraz skaning laserowy LS, w procesie...
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Method of selective fading as a educational tool to study the behaviour of prestressed concrete elements under excess loading
PublikacjaPrestressed structures are a key to realization of the boldest architectural ideas, characteristic feature of prestressed structure is better use of concrete material properties by insertion of internal forces. Learning about pre-stressed reinforced concrete structures is an integral part of Graduate Studies Program in construction engineering. Know-how of geometry change patterns in prestressed concrete elements under certain...
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Gas Composition Influence on the Properties of Boron-Doped Diamond Films Deposited on the Fused Silica
PublikacjaThe main subject of this study are molecular structures and optical properties of boron-doped diamond films with [B]/[C] ppm ratio between 1000 and 10 000, fabricated in two molar ratios of CH 4 -H 2 mixture (1 % and 4 %). Boron-doped diamond (BDD) film on the fused silica was presented as a conductive coating for optical and electronic purposes. The scanning electron microscopy images showed homogenous and polycrystalline surface...
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Corrosion behavior of hydrogen charged super duplex stainless steel welded joints
PublikacjaThe electrochemical behavior of the weld metal, heat-affected zone (HAZ), and base material of super duplex stainless steel (SDSS) welded joints, made with the application of flux-cored arc welding (FCAW) and submerged arc welding (SAW), were investigated with the use of metallographic examinations (optical microscopy and scanning electron microscopy), potentiodynamic polarization measurements and total hydrogen content determination...
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Laser patterned platform with PEDOT–graphene composite film for NO2 sensing
PublikacjaThis work presents a simple and fully electrochemical route used for fabricating of a NO2 gas sensor made of reduced-graphene-oxide-poly(3,4-ethylenedioxythiophene) composite film. The sensing platform was fabricated from alumina substrate and equipped with gold interdigitated electrodes and built-in heater.The temperature distribution on the surface of interdigitated electrodes was investigated by a thermalimaging camera and compared...
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A new method of presosns identification based on comparative analysis of 3D face models
PublikacjaThe article presents the use of modern close range photogrammetry for possessing highly accurate 3D models of the human face (including the ears). Modern methods used to obtain precise data describing the construction of a human face, and even the whole human body, should allow to get finished measurement material in a very short time. Those features belong to the optical scanning technology. Comparative analysis of models of the...
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Properties of Composite Oxide Layers on The Ti13Nb13Zr Alloy
PublikacjaThe development of composite oxide layers on the Ti13Nb13Zr alloy, their structure and properties have been demonstrated. Two subsequent methods were applied to prepare the composite layers. During the first stage gas oxidation produced a solid oxide layer, and subsequently oxide nanotubes were produced by using an electrochemical method. Scanning electron microscopy (SEM), chemical analysis, energy dispersive X-ray spectroscopy...
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Point cloud based surface analysis of prestressed concrete element in exceeded state of serviceability
PublikacjaBy definition, serviceability state is characterized by the fact that despite meeting the requirements associated with carrying capacity, the object is not suitable for use. Serviceability limit state refers to factors, such as durability, overall stability, fire resistance, cracking, excessive vibration. Perfect examples of exceeded serviceability state are the improper vibration of a skyscraper, which inhabitants may suffer from...
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Zirconia ceramics with additions of Alumina for advanced tribological and biomedical applications
PublikacjaThe results of an investigation on slip cast and sintered Y2O3 (3 wt%)- stabilized ZrO2 with additions of 5, 10, 15 wt% Al2O3 are reported. The surface roughness, porosity and density of the samples were measured. The hardness HRc and Hv, fracture toughness K1C, and friction coefficients were also measured using standard methods. The structural properties of the samples were observed by Scanning Electron Microscopy (SEM). The surface...
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Mono- and bimetallic (Pt/Cu) titanium(IV) oxide photocatalysts. Physicochemical and photocatalytic data of magnetic nanocomposites’ shell
PublikacjaSurface modification of titania with noble and semi-noble metals resulted in significant enhancement of photocatalytic activity. Presented data, showing the photocatalytic properties of TiO2-M (where M is Pt and/or Cu) photocatalysts were further used as Fe3O4@SiO2/TiO2-M magnetic nanocomposites shells in "Mono- and bimetallic (Pt/Cu) titanium(IV) oxide core-shell photocatalysts with Vis light activity and magnetic separability"...
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Two kinds of oxygen vacancies in lithium titaniate doped with copper as detected by EPR
PublikacjaLithium titanate (Li1+xTi2-xO4) doped with Cu2+ ions was synthesized by sol-gel processing method. The structure and morphology are characterized by X-ray Diffraction (XRD), X-ray Photoemission Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). Spin Hamiltonian parameters describing Zeeman and hyperfine interaction for 63Cu2+ ions were obtained from EPR spectra simulations. The spectra...
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Influence of Two-Stage Anodization on Properties of the Oxide Coatings on the Ti–13Nb–13Zr Alloy
PublikacjaThe increasing demand for titanium and its alloys used for implants results in need of such innovative surface treatment that may jointly increase corrosion resistance and biocompatibility, and demonstrate antibacterial protection at no cytotoxicity. The purpose of this research was to characterize the effect of two-stage anodization, performed for 30 min in phosphoric acid, at the presence of hydrofluoric acid in the second stage....
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Weighted Clustering for Bees Detection on Video Images
PublikacjaThis work describes a bee detection system to monitor bee colony conditions. The detection process on video images has been divided into 3 stages: determining the regions of interest (ROI) for a given frame, scanning the frame in ROI areas using the DNN-CNN classifier, in order to obtain a confidence of bee occurrence in each window in any position and any scale, and form one detection window from a cloud of windows provided by...
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High temperature oxidation behavior of SUS430 SOFC interconnects with Mn-Co spinel coating in air
PublikacjaIn this study, SUS430 alloy is evaluated for its high temperature corrosion properties as a possible material for interconnects of solid oxide fuel cells (SOFCs). Samples are coated with Mn-Co by commercial physical vapor deposition (PVD) process and oxidized in air for 1250 h at 800 °C. A dense cubic Mn-Co-Fe spinel layer is formed on the surface, showing great effect on corrosion reduction compared with the samples without coating....
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Physico‐Mechanical Properties and Flammability of PUR/PIR Foams Containing Expandable Graphite Core‐Shell Composite Particles
PublikacjaIn this work, polyurethane/polyisocyanurate (PUR/PIR) foams were modified by two types of expandable graphite (EG) core-shell composite particles. The pulverized EG core-shell composite particles were prepared during emulsion polymerization using methyl methacrylate or glycidyl methacrylate for the synthesis of the polymeric shells (poly(methyl methacrylate) (PMMA) and poly (glycidyl methacrylate) (PGMA)), and then the obtained EG_PMMA...
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Titania Nanotubes/Hydroxyapatite Nanocomposites Produced with the Use of the Atomic Layer Deposition Technique: Estimation of Bioactivity and Nanomechanical Properties
PublikacjaTitanium dioxide nanotubes/hydroxyapatite nanocomposites were produced on a titanium alloy (Ti6Al4V/TNT/HA) and studied as a biocompatible coating for an implant surface modification. As a novel approach for this type of nanocomposite fabrication, the atomic layer deposition (ALD) method with an extremely low number of cycles was used to enrich titania nanotubes (TNT) with a very thin hydroxyapatite coating. X-ray diffraction (XRD)...
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Damage imaging algorithm for non-destructive inspection of CFRP/steel adhesive joints based on ultrasonic guided wave propagation
PublikacjaThe paper concerns assessing the quality of the adhesive connection between a steel plate and the reinforcing CFRP laminate. A three-stage algorithm for non-destructive damage imaging was developed. As the first step, an initial study involving dispersion curves of joint components was executed to determine the material parameters and the appropriate excitation frequency. During the second step, damage identification in three-layer...
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Scaling Up the Process of Titanium Dioxide Nanotube Synthesis and Its Effect on Photoelectrochemical Properties
PublikacjaIn this work, for the first time, the influence of scaling up the process of titanium dioxide nanotube (TiO2NT) synthesis on the photoelectrochemical properties of TiO2 nanotubes is presented. Titanium dioxide nanotubes were obtained on substrates of various sizes: 2 × 2, 4 × 4, 5 × 5, 6 × 6, and 8 × 8 cm2. The electrode material was characterized using scanning electron microscopy as well as Raman and UV–vis spectroscopy in order...
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Testing of the longest span soil-steel bridge in Europe – new quality in measurements
PublikacjaThe article describes interdisciplinary and comprehensive diagnostic tests of final bridge inspection and acceptance proposed for a soil – steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure response was collected. The load test design was based on the nonlinear numerical simulations performed by...
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Use of Bi-Temporal ALS Point Clouds for Tree Removal Detection on Private Property in Racibórz, Poland
PublikacjaTrees growing on private property have become an essential part of urban green policies. In many places, restrictions are imposed on tree removal on private property. However, monitoring compliance of these regulations appears difficult due to a lack of reference data and public administration capacity. We assessed the impact of the temporary suspension of mandatory permits on tree removal, which was in force in 2017 in Poland,...
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Influence of alkali metal cations on the photoactivity of crystalline and exfoliated amorphous WO3 – photointercalation phenomenon
PublikacjaIn order to investigate the effect of photointercalation on photoelectrochemical properties, two types of WO3-based photoanodes, bulk and exfoliated have been prepared and investigated. An aqueous exfoliation method is introduced for the simple fabrication of amorphous and hydrated WO3 nanomaterial using commercial bulk WO3 precursor. The comparison of obtained material with bulk WO3 was performed using Raman, UV–vis, and XPS as...
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Mechanical Behavior of Bi-Layer and Dispersion Coatings Composed of Several Nanostructures on Ti Substrate
PublikacjaThree coatings suitable for biomedical applications, including the dispersion coating composed of multi-wall carbon nanotubes (MWCNTs), MWCNTs/TiO2 bi-layer coating, and MWCNTs-Cu dispersion coating, were fabricated by electrophoretic deposition (EPD) on Ti Grade II substrate. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and nanoindentation were applied to study topography, chemical, and...
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Facile synthesis and characterization of graphene and N-doped graphene by CVD method from liquid precursors for promising electrode materials
PublikacjaIn this study, high-quality and few-layered graphene was synthesized using the chemical vapor deposition (CVD) method from liquid sources. Two different liquid carbon sources, pyridine, and benzene, were used and deposited on nickel foam under heat conditions using a bubbler in a quartz tube. X-ray diffraction (XRD) and Raman analysis confirmed the crystalline properties of graphene and N-doped graphene, demonstrating the high...
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A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublikacjaIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
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Effect of Laser Treatment on Intrinsic Mechanical Stresses in Titanium and Some of Its Alloys
PublikacjaLaser surface treatment conducted at different power levels is an option to modify titanium bone implants to produce nano- and microtopography. However, such processing can lead to excess mechanical stress within the surface layer. This research aims to calculate the level of such residual stresses after the surface processing of Ti grade IV, Ti15Mo, and Ti6Al7Nb alloys with an Nd:YAG laser. Light and scanning electron microscopies...
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The Effect of C45 Carbon Black-Phosphomolybdic Acid Nanocomposite on Hydrogenation and Corrosion Resistance of La2Ni9Co Hydrogen Storage Alloy
PublikacjaIn this paper, we analysed the influence of corrosion processes and the addition of a carbon black-heteropoly phosphomolybdic acid (C45-MPA) nanocomposite on the operating parameters of a hydride electrode obtained on the basis of the intermetallic compound La2Ni9Co. The electrochemical properties of negative electrodes for NiMH batteries were studied using galvanostatic charge/discharge curves, the potentiostatic method, and electrochemical...
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Evaluation of the Cathodic Electrodeposition Effectiveness of the Hydroxyapatite Layer Used in Surface Modification of Ti6Al4V-Based Biomaterials
PublikacjaThe important issue associated with the design and the fabrication of the titanium and titanium alloy implants is the increase of their biointegration with bone tissue. In the presented paper, the research results concerning the conditions used in the cathodic deposition of hydroxyapatite on the surface Ti6Al4V substrates primarily modified by the production of TiO2 nanoporous coatings, TiO2 nanofibers, and titanate coatings, are...
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Electrocatalytic oxidation of methanol, ethylene glycol and glycerine in alkaline media on TiO2 nanotubes decorated with AuCu nanoparticles for an application in fuel cells
PublikacjaIn this work, we present the catalytic and photocatalytic activity of AuCu nanostructures obtained on TiO2 nanotubes toward methanol, ethylene glycol and glycerine oxidation. The electrode material is prepared by anodization of Ti foil, thin AuCu layer sputtering and rapid thermal treatment under argon atmosphere. Scanning electron microscopy images confirmed the presence of ordered tubular architecture of TiO2 as well as nanoparticles...
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Precipitation of Spherical Vaterite Particles via Carbonation Route in the Bubble Column and the Gas-Lift Reactor
PublikacjaSpherical vaterite particles were produced by carbonation of calcium chloride solution with addition of ammonia to facilitate CO2 absorption. Synthesis of calcium carbonate was carried out in a bubble column or gas-lift reactor. The course of the reaction was monitored by pH measurements. Precipitated solids were analyzed by Fourier-transformed infrared spectroscopy, x-ray powder diffraction and scanning electron microscopy, and...
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Analytical Steady-State Model of the Pipeline Flow Process
PublikacjaThe paper addresses the issue of modeling the flow process in transmission pipelines. A base model used for numerical simulation is introduced. Under certain assumptions concerning steady state analysis, the differential equations describing the process are solved analytically for two cases: zero and nonzero inclination angle α. These equations describe a constant flow rate and a corresponding distribution of the pressure along...
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Social media and efficient computer infrastructure in smart city
PublikacjaSocial media require an efficient infrastructures of computer and communication systems to support a smart city. In a big city, there are several crucial dilemmas with a home and public space planning, a growing population, a global warming, carbon emissions, a lack of key resources like water and energy, and a traffic congestion. In a smart city, we expect an efficient and sustainable transportation, efficient management of resources...
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Safety integrity level verification for safety-related functions with security aspects
PublikacjaThe article is devoted some important issues of the functional safety analysis, in particular the safetyintegrity level (SIL) verification of safety functions to be implemented within the distributed controland protection systems with regard to cyber security aspects. The procedure for functional safety man-agement includes hazard identification, risk analysis and assessment, specification of overall safetyrequirements and definition...
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Electron-impact dissociation of molecular hydrogen: benchmark cross sections
PublikacjaWe present a joint experimental and theoretical investigation of a fundamental process in atomic and molecular physics: electron impact excitation of molecular hydrogen’s (H2) most dominant transition (X1Σg+ → b3Σu+). Excitation of this state is by far the main channel that causes the dissociation of H2 into H + H atoms at low energies. The Convergent Close-Coupling (CCC) calculations predicted significant, more than factor of...
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Determining and verifying the safety integrity level of the safety instrumented systems with the uncertainty and security aspects
PublikacjaSafety and security aspects consist of two different group of functional requirements for the control and protection systems. In the paper it is proposed that the security analysis results can be used as a factor increasing or decreasing the risk level. It concerns a process of determining required safety integrity level of given safety functions. The authors propose a new approach for functional safety risk analysis. In this case...
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Emotion Recognition from Physiological Channels Using Graph Neural Network
PublikacjaIn recent years, a number of new research papers have emerged on the application of neural networks in affective computing. One of the newest trends observed is the utilization of graph neural networks (GNNs) to recognize emotions. The study presented in the paper follows this trend. Within the work, GraphSleepNet (a GNN for classifying the stages of sleep) was adjusted for emotion recognition and validated for this purpose. The...
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Thermal buckling of functionally graded piezomagnetic micro- and nanobeams presenting the flexomagnetic effect
PublikacjaGalerkin weighted residual method (GWRM) is applied and implemented to address the axial stability and bifurcation point of a functionally graded piezomagnetic structure containing flexomagneticity in a thermal environment. The continuum specimen involves an exponential mass distributed in a heterogeneous media with a constant square cross section. The physical neutral plane is investigated to postulate functionally graded material...
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THE RESEARCH ON EGNOS SYSTEM IN CONTEXT OF THE ABILITY TO DETERMINE THE SHIP’S HULL SPATIAL ORIENTATION
PublikacjaThe European Geostationary Navigation Overlay Service (EGNOS) thanks to geostationary satellites covers an area of whole Europe, including Baltic and North Sea. It allows to fix the coordinates of object position with typical absolute accuracy of 1,5 m. Previous research have shown that relative accuracy is usually higher than absolute one [Nowak A., 2010, Nowak A., 2011], so probably it could be possible to use EGNOS to determine...