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Search results for: unsteady surface flow
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Numerical simulations of granular material flow in silos with and without insert
PublicationArtykuł omawia wyniki naporu materiału sypkiego podczas przepływu w silosach z i bez wkładek. Obliczenia wykonano wykorzystując sformułowanie ale na bazie prawa sprężysto-plastycznego według druckera-pragera. Zbadano wpływ kształtu i położenia wkładki na wielkość naporu i rodzaj przepływu.
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Experimental and theoretical investigations of silo music during granular flow
PublicationPraca dotyczy analizy efektów dynamicznych w silosach podczas przeływu materiałów sypkich.
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Experimental and theoretical studies of resonance effects during silo flow.
PublicationPrzedstawiono badania nad rezonansowymi efektami dynamicznymi podczas przepływów silosowych. Wpływ rezonansu na wielkość naporu był analizowany przy pomocy badań doświadczalnych i obliczeń MES na bazie prawa mikropolarnego sprężysto-plastycznego. Doświadczenia wykonano w silosie o przekroju okrągłym i prostokątnym. Zaproponowano efektywną metodę redukcji efektów dynamicznych.
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Numerical modeling of shear localizations during granular flow in silos.
PublicationW artykule przedstawiono wyniki numerycznej analizy MES dotyczącej przepływów materiałów sypkich w silosach. Omówiono różne metody opisu lokalizacji odkształceń stycznych wewnątrz materiałów. Wyniki porónano z wynikami doświadczalnymi.
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Simulations of flow patterns in silos with a cellular automaton - part 2
PublicationW artykule przedstawiono wyniki symulacji przepływów silosowych przy zastosowaniu zaawansowanego aparatu komórkowego, w którym uwzględniono kolizje cząstek i dysypację energii. Obliczenia wykonano dla przepływu masowego i kominowego.
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Methods for quality improvement of multibeam and LiDAR point cloud data in the context of 3D surface reconstruction
PublicationPoint cloud dataset is the transitional data model used in several marine and land remote-sensing applications. During further steps of processing, the transformation of point cloud spatial data to more complex models containing higher order geometric structures like edges and facets may be possible, if an appropriate quality level of input data is provided. Point cloud datasets usually contain a considerable amount of undesirable...
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The interplay between dopant and a surface structure of the photocatalyst – The case study of Nb-doped faceted TiO2
PublicationAnatase nanoparticles, exposing the majority of the {0 0 1}, {1 0 0} and {1 0 1} facets were synthesized and doped with different niobium amount to investigate the self-trapping of the excess electrons and resulting photocatalytic activity. Photocatalyst structure and presence of excess electrons inside the obtained Nb-doped anatase samples was confirmed by the combination of structural and spectroscopic analyses. Only for the...
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Evaluation of the Cathodic Electrodeposition Effectiveness of the Hydroxyapatite Layer Used in Surface Modification of Ti6Al4V-Based Biomaterials
PublicationThe 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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TIME-DOMAIN NUMERICAL EVALUATION OF SHIP RESISTANCE AND MOTION IN REGULAR WAVES BY USING THE CFD URANS METHOD
PublicationTaking into account the International Maritime Organization's (IMO) strategy to radically reduce the...
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Actual field corrosion rate of offshore structures in the Baltic Sea along depth profile from water surface to sea bed
PublicationThe paper presents the results of field electrochemical investigations on the corrosion rate of carbon steel in seawater of the Baltic Sea at the location of the Baltic Beta production rig. The measurements were conducted throughout the year in seawater at different depths from the sea surface to the sea bed (about 75 m). The results revealed corrosion aggressiveness of the seawater along the entire depth profile. There was...
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Continuum contact model for friction between graphene sheets that accounts for surface anisotropy and curvature
PublicationUnderstanding the interaction mechanics between graphene layers and co-axial carbon nanotubes (CNTs) is essential for modeling graphene and CNT-based nanoelectromechanical systems. This work proposes a new continuum contact model to study interlayer interactions between curved graphene sheets. The continuum model is calibrated and validated using molecular dynamics (MD) simulations. These are carried out employing the reactive...
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Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes
PublicationFlow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighboring nodes or cells of the numerical...
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The corrosion resistance of laser surface alloyed stainless steels
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Design of Ground Surface Sealing in The Spatial Policy of Communes
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The Effect of Spikes Occurrence on Surface Texture Parameter Assessments
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Entropy analysis of surface EMG for classification of face movements
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Profile and Areal Surface Parameters for Fatigue Fracture Characterisation
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Unusual interfacial phenomena at a surface of fullerite and carbon nanotubes
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Post-plasma oxidation in water of graphene paper surface
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Surface treatment of porous Ti13Nb13Zr alloy for biomedical applications
PublicationPrzeprowadzono badania materiału porowatego, przeznaczonego na implanty ortopedyczne, wytworzonego metodą metalurgii proszków ze stopu Ti13Nb13Zr. Proszki z badanego stopu uzyskano metodą rozpylania plazmowego. Otrzymano próbki o otwartej porowatej strukturze, stopniu porowatości do 68% i średniej wielkości porów w przedziale 30-150 mikrometrów. Obróbka próbek porowatych - utlenianie termiczne, chemiczne i/lub elektrochemiczne...
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Surface roughness chracteristic if components created by stereolithography method
PublicationModele wykonywane metodami szybkiego prototypowania mają charakterystyczna strukturę powierzchni określaną mianem schodkowatości. W artykule przedstawiono modele obliczeniowe profilu nierówności jak i porównanie ich z wynikami pomiarów
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Surface Roughness Model Components Created by Stereolithography Method
PublicationW pracy przedstawiono charakterystykę powierzchni elementów wykonywanych metodą stereolitografii. Opisano modele chropowatosci stosowane do opisywania powierzcni wraz z prezentacją formuł matematycznych. W oparciu o wyniki badań eksperymentalnych przeprowadzono częściową weryfikację modeli.
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EFFECT OF THE BIO-LUBRICANT ON THE LUBRICATINGPROPERTIES AND SURFACE OF THE FRICTION ZONE
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New laser-enhanced surface treatment of Ti bioalloy
PublicationPrzedstawiono wyniki badan mikrostruktury i korozji w roztworze Ringera stopu Ti6Al4V, który był poddawany nadtapianiu laserem CO2 w powietrzu, wodzie i ciekłym azocie. Stwierdzono znaczący wpływ warunków obróbki na mikrostrukturę, mikrotwardość i głębokość zmodyfikowanej warstwy wierzchniej.
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Monitoring surfactant concentrations in surface waters in Tricity agglomeration.
PublicationCelem prowadzonych badań było monitorowanie zawartości związków powierzchniowo- czynnych w wybranych rzekach Trójmiasta i Zatoki Gdańskiej. Badania prowadzono w okresie od listopada 2001 do maja 2002 r. W badanych strumieniach wodnych zanotowano niskie stężenia anionowych związków powierzchniowo czynnych (5-10ćg/dm3). Najwyższą zawartość surfaktantów zaobserwowano w potoku Strzyża i rzece Kacza. Najmniej zanieczyszczonym...
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Surface chemistry aspects of fluorosurfactants as components in AFFF preparation
PublicationZbadano właściwości powierzchniowe fluorowanych surfaktantów anionowych a także roztworów środków pianotwórczych na bazie fluorowanych surfaktantów stosowanych w gaszeniu pożarów substancji ropopochodnych ze szczególnym uwzględnieniem ich zdolności do obniżania napięć międzyfazowych. Wyselekcjonowana para surfaktantów wykazała się wysoką zdolnością obniżania napięć międzyfazowych na granicy faz olej-woda, porównywalną z roztworami...
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The surface contact characteristics after sliding and rolling burnishing.
PublicationW pracy przedstawiono zastosowanie nowej metody SCGC i odpowiedniego programu komputerowego JKC do oceny pomierzonej mikrostereometrii powierzchni części maszyn, głównie na potrzeby kontroli jakości. Na przykładzie powierzchni nagniatanych wykazano cechy nowej metody: wizualizację ułatwiającą wyobrażenie pomierzonej sfery chropowatości, położenie w niej najważniejszych parametrów oceny (rozkład geometrycznej powierzchni kontaktu,...
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Fatigue test bearings with geometrically modyfied sliding surface.
PublicationW artykule uzasadniono celowość wprowadzenia nowego łóżyska testowego do badań wytrzymałości zmęczeniowej materiałów łożyskowych. Przedstawiono wstępne wyniki badań łożysk o zmodyfikowanej geometrii powierzchni ślizgowej i porównano otrzymane wyniki testów przeprowadzonych przy użyciu o standartowej geometrii.
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A surface panel method for hydrodynamic analysis of pod propulsors
PublicationPraca przedstawia zastosowanie metody elementów brzegowych do analizy hydrodynamicznych pędników azymutalnych, czyli do wyznaczania rozkładu ciśnienia i wielkości sił hydrodynamicznych dla pędnika o znanej geometrii i o znanych parametrach pracy.
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Some aspects of laser surface remelting of aluminium alloys
PublicationPodano podstawy procesu przetapiania laserowego stopów aluminium. Opisano rezultaty elektrochemicznych badań korozyjnych dla stopu AlSi13Mg1CuNi i porównano je ze stanem wyjściowym stopu.
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Surface layer defects on injection-molded plastic components
PublicationProces wtryskiwania jakkolwiek jest powszechnie stosowany w przemyśle nie jest jeszcze do końca przebadany. W pracy przedstawiono model i symulację numeryczna procesu wtryskiwania wykonaną na bazie programu FIDAP. Na tej podstawie przedstawiono proces zachowania się tworzywa podczas procesu wtryskiwania w strefie przyściennej formy. Wyniki z symulacji porównano z danymi ekspermentalnymi.
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Laser surface treatment of aluminium alloys at cryogenic conditions.
PublicationPrzedstawiono nową metodę obróbki laserowej powierzchni stopów aluminium w warunkach kriogenicznych. W wyniku tej obróbki w warstwie wierzchniej stopów przeznaczonych na tłoki silników spalinowych uzyskano znaczące podwyższenie twardości, odporności na zużycie ścierne oraz wzrost właściwości korozyjnych.
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Computer Supported Analysis of the Human Body Surface Area
PublicationRecent scientific studies show the growing importance of the coefficients: BSA and TBSA, as an alternative to the widely used BMI. The relevant indicators are widely used in medicine, including such areas as: the treatment of burns, chemotherapy, dermatology and toxicology; as benchmarks when calculating doses of drugs and fluids. The particular problems concerning this subject are: the change of the reference parameter value which...
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Estimation of wear of electroplated tools used for surface grinding
PublicationW pracy dokonano ilościowej oceny zużycia narzędzi galwanicznych diamentowych i borazonowych. Wykorzystano analizę jasności obrazów narzędzi oraz badano liczność ziaren ściernych na czynnej powierzchni narzędzia.
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Surface Roughness Evaluation in Thin EN AW-6086-T6 Alloy Plates after Face Milling Process with Different Strategies
PublicationLightweight alloys made from aluminium are used to manufacture cars, trains and planes. The main parts most often manufactured from thin sheets requiring the use of milling in the manufacturing process are front panels for control systems, housing parts for electrical and electronic components. As a result of the final phase of the manufacturing process, cold rolling, residual stresses remain in the surface layers, which can influence...
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Impact of diffusion coefficient averaging on solution accuracy of the 2D nonlinear diffusive wave equation for floodplain inundation
PublicationIn the study, the averaging technique of diffusion coefficients in the two-dimensional nonlinear diffusive wave equation applied to the floodplain inundation is presented. As a method of solution, the splitting technique and the modified finite element method with linear shape functions are used. On the stage of spatial integration, it is often assumed that diffusion coefficient is constant over element and equal to its average...
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To what extent can hyperelastic models make sense the effect of clay surface treatment on the mechanical properties of elastomeric nanocomposites?
PublicationThe poor knowledge about nonlinear mechanical behavior of elastomer nanocomposites arises from the incomplete information on the interface. Application of hyperelastic models provides more insights into the nature and the situation of interaction between the elastomeric matrix and nanofillers. The current work seeks to address the effect of interphase strength on tensile properties of the elastomer nanocomposites under large deformations....
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Changes on the Surface of the SiO2/C Composite, Leading to the Formation of Conductive Carbon Structures with Complex Nature of DC Conductivity
Open Research DataChanges on the Surface of the SiO2/C Composite, Leading to the Formation of Conductive Carbon Structures with Complex Nature of DC Conductivity
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Frequency Selective Surface Based MIMO Antenna Array for 5G Millimeter-Wave Applications
PublicationAbstract: In this paper a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2×2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabri-cated on Rogers RT/Duroid high frequency substrate...
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Cell Surface
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Modeling of medium flow processes in transportation pipelines - the synthesis of their state-space models and the analysis of the mathematical properties of the models for leak detection purposes
PublicationThe dissertation concerns the issue of modeling the pipeline flow process under incompressible and isothermal conditions, with a target application to the leak detection and isolation systems. First, an introduction to the model-based process diagnostics is provided, where its basic terminology, tools, and methods are described. In the following chapter, a review of the state of the art in the field of leak detection and isolation...
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Concentration and sources of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in surface soil near a municipal solid waste (MSW) landfill
PublicationDue to a continuous demand of land for infrastructural and residential development there is a public concern about the condition of surface soil near municipal solid waste landfills. A total of 12 surface (0–20 cm) soil samples from a territory near a landfill were collected and the concentration of 16 PAHs and 7 PCB congeners were investigated in these samples. Limits of detection were in the range of 0.038–1.2 μg/kg for PAHs...
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Corrosion Inhibition of Aluminium Alloy AA6063-T5 by Vanadates: Local Surface Chemical Events Elucidated by Confocal Raman Micro-Spectroscopy
PublicationChemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on...
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Local response surface approximations and variable-fidelity electromagnetic simulations for computationally efficient microwave design optimisation
PublicationIn this study, the authors propose a robust and computationally efficient algorithm for simulation-driven design optimisation of microwave structures. Our technique exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimised using its local response surface approximation surrogates. The high-fidelity model is refined by space mapping with polynomial interpolation of...
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The phenomenon of increasing capacitance induced by 1T/2H-MoS2 surface modification with Pt particles – Influence on composition and energy storage mechanism
PublicationIn this paper, several approaches to the synthesis of molybdenum-based electrode materials for supercapacitors are presented, including anodization, hydrothermal process and annealing. For the material prepared via anodization of a molybdenum plate, followed by a hydrothermal process in thiourea aqueous solution, a thorough study of the Pt-surface modification through repetitive cycling in 1 M sulfuric acid with Pt acting as a...
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Deterministic versus stochastic modelling of unsaturated flow in a sandy field soil based on dual tracer breakthrough data
PublicationThe 216 km2 Neuenhagen Millcreeck catchment can be characterized as a drought sensitive landscape in NE Germany. It is therefore a fundamental human interest to understand how water that fell as precipitation moves through the unsaturated soils and recharges groundwater. Additionally, a better knowledge of nutrient transport from soil to groundwater is important also, especially in landscapes with light sandy soils. For a better...
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A High-Arctic flow-through lake system hydrochemical changes: Revvatnet, southwestern Svalbard (years 2010–2018)
PublicationLake ecosystems are strongly coupled to features of their surrounding landscapes such as geomorphology, lithology, vegetation and hydrological characteristics. In the 2010–2018 summer seasons, we investigated an Arctic flow-through lake system Revvatnet, located in the vicinity of the coastal zone of Hornsund fjord in Svalbard, characterising its hydrological properties and the chemical composition of its waters. The lake system...
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Improved surface coverage of an optical fibre with nanocrystalline diamond by the application of dip-coating seeding
PublicationGrowth processes of diamond thin films on the fused silica optical fibres (10 cm in length) were investigated at various temperatures. Fused silica pre-treatment by dip-coating in a dispersion consisting of detonation nanodiamond (DND) in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) was applied. Nanocrystalline diamond (NCD) films were deposited on the fibres using the microwave plasma assisted chemical vapour deposition...
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Effect of Surface Treatment of Halloysite Nanotubes (HNTs) on the Kinetics of Epoxy Resin Cure with Amines
PublicationThe epoxy/clay nanocomposites have been extensively considered over years because of their low cost and excellent performance. Halloysite nanotubes (HNTs) are unique 1D natural nanofillers with a hollow tubular shape and high aspect ratio. To tackle poor dispersion of the pristine halloysite (P-HNT) in the epoxy matrix, alkali surface-treated HNT (A-HNT) and epoxy silane functionalized HNT (F-HNT) were developed and cured with...
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Seafloor characterisation using multibeam data: sonar image properties, seabed surface properties and echo properties
PublicationIn the paper, the approach to seafloor characterisation is presented. The multibeam sonars, besides their well verified and widely used applications like high resolution bathymetry and underwater object detection and imaging, are also the promising tool in seafloor characterization and classification, having several advantages over conventional single beam echosounders. The proposed approach relies on the combined, concurrent use...