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Wyniki wyszukiwania dla: SHELL
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Fem and time stepping procedures in non-linear dynamics of flexible branched shell structures.
PublikacjaW pracy dyskutowano problemy całkowania równań ruchu, sformułowanych w ramach nieliniowej sześcioparametrowej teorii powłok. Główne myśli dotyczą zbieżności rozwiązań uzyskanych w procesie aproksymacji przestrzennej i czasowej oraz analizy stabilności rozwiązań MES.
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Bridge over Vistula river in Kiezmark. Practical application of nonlinear shell FEM system
PublikacjaPo 40 latach eksploatacji, most drogowy przez rzekę Wisłę w Kiezmarku wymagał wzmocnienia, wynikającego z podniesienia klasy obciążenia do aktualnych wymogów klasy "A". W trakcie prac nad modernizacją konstrukcji, stwierdzono ponad normowe deformacje środników we wszystkich dźwigarach przęseł mostu. Miały one charakter pierwotny i były wynikiem niedbałego wykonania konstrukcji. W referacie przedstawiono wyniki analiz numerycznych...
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Specific risks for local stability and capacity of verticat doble - shell cylindrical steel tanks
PublikacjaOmówiono zagrożenia stateczności i nosności płaszczy zbiorników dwupłaszczowych wywołane przez: niefachowo prowadzoną próbę wodną, dużną różnicę temperatury podczas eksploatacji oraz nierównomierne osiadanie. W księdze konferncyjnej opublikowano dwustronicowe streszczenie referatów a na załączonej płycie referaty zamieszczone są w całości.
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Galerkin formulations with Greville quadrature rules for isogeometric shell analysis: Higher order elements and locking
PublikacjaWe propose new Greville quadrature schemes that asymptotically require only four in-plane points for Reissner-Mindlin (RM) shell elements and nine in-plane points for Kirchhoff-Love (KL) shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree of the elements. For polynomial degrees 5 and 6, the approach delivers high accuracy, low computational cost, and alleviates membrane and...
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Galerkin formulations of isogeometric shell analysis: Alleviating locking with Greville quadratures and higher-order elements
PublikacjaWe propose new quadrature schemes that asymptotically require only four in-plane points for Reissner–Mindlin shell elements and nine in-plane points for Kirchhoff–Love shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree p of the elements. The quadrature points are Greville abscissae associated with pth-order B-spline basis functions whose continuities depend on the specific...
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Comparison of buckling resistance of columns modelled by beam and shell elements using non-linear analysis
PublikacjaThe aim of the paper is to investigate the stability process in the axially compressed columns modelled by beam and shell elements using static and dynamic finite element analysis by taking both the geometric and material non-linearity into account. The perfect columns and columns with geometric imperfections were analysed. The differences between the results of static and dynamic analyses in shell and beam models were discussed.
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Experimental investigations on heat transfer enhancement in shell coil heat exchanger with VARIABLE Baffles GEOMETRY
PublikacjaThe paper presents the possibility of using passive intensification of heat transfer in the form of baffles to increase the energy efficiency of the shell and coil heat exchanger. The experiment was carried out by using a modular coil heat exchanger in the form of an electric heater. Water was used as a working fluid with constant thermal-flow parameters at the inlet of the module. It should be noted that experiments were made...
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Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine
PublikacjaIn this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope...
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Estimation of Failure Initiation in Laminated Composites by means of Nonlinear Six-Field Shell Theory and FEM
PublikacjaThe monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...
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Viscoplastic damage analysis of structures subjected to impact loading. Plate and shell structures. - Ł. Pyrzowski.
PublikacjaThe work presents the investigation in the response of plate-shell structures subjected to impact loading (gas mixture explosions). This phenomenon is studied in the context of its mechanical aspects, mainly the ductile fracture prediction. The work starts with the literature review and the description of theories, which are nowadays the most popular in the damage and failure modelling. After selecting the theoretical models and...
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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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Influence of silver-core gold-shell nanoparticle parameters on the variation of surface-enhanced Raman spectra
PublikacjaThe detection of molecules by surface-enhanced Raman spectroscopy (SERS) is dependent on the nanomaterial used to induce the enhancement effect. This depends on a variety of parameters of the substrate such as the metal used for their creation, their shape, size and size distribution, concentration, as well as the parameters of the solution, such as packing of the nanoparticles, the complexity of the sample, the solvent, etc. It...
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Chitosan-coated coconut shell composite: A solution for treatment of Cr(III)-contaminated tannery wastewater
PublikacjaTannery industry generates a large amount of Cr(III)-contaminated wastewater daily. Unless properly treated, not only this effluent contaminates the water body, but also damages the environment and threatens public health. This batch study investigates the feasibility of chitosan-coated coconut shells as a low-cost material for removing Cr(III) from tannery wastewater. Both chitosan and coconut shell (CS) waste are abundantly available...
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side
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Core/Shell Structure of Mesoporous Carbon Spheres and g-C3N4 for Acid Red 18 Decolorization
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On the use of enhanced strain formulation in 6-field nonlinear shell theory with asymetric strain measures
PublikacjaW pracy zbadano możliwość zastosowania techniki wzbogaconych odkształceń do usunięcia zjawiska blokady w elementach skończonych opracowanych w ramach 6-parametrowej nieliniowej teorii powłok z niesymetrycznymi miarami odkształceń membranowych. Przedstawiono i porównano 4 warianty pol wzogacających odkształcenia
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Wind tunnel experiments and numerical analysis of the wind load on double-shell cylindrical, vertical tanks
PublikacjaW pracy przedstawiono wyniki badań modelowych w tunelu aerodynamicznym oraz symulacji komputerowych obciążenia wiatrem pionowych, walcowych zbiorników dwupłaszczowych z dachem pływającym. W badaniach modelowych analizowano wpływ rozstawu między płaszczami zbiornika na wartość i rozkład współczynnika ciśnienia na płaszczach oraz dachu pływającym. Wyniki symulacji komputerowych przeprowadzonych w programie Fluent porównano z wynikami...
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The influence of height-do-diameter ratio on wind load of double-shell cylindrical, vertical tank
PublikacjaW pracy zaprezentowano skrót badań modelowych obciążenia wiatrem dwupłaszczowych zbiorników walcowych o różnych smukłościach aerodynamicznych. Przedstawiono wyniki pomiarów przeprowadzonych na dwóch modelach zbiorników z dachem pływającym i stosunku wysokości do średnicy płaszcza 0,45 i 0,25.
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One-pot self-assembly of three-dimensional graphene macroassemblies with porous core and layered shell
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Synthesis, characterization, and photocatalytic properties of core/shell mesoporous silica nanospheres supporting nanocrystalline titania
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Decisive role of vacuum-assisted carbonization in valorization of lignin-enriched (Juglans regia-shell) biowaste
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Damage detection strategies for aircraft shell-like structures based on propagation guided elastic waves
PublikacjaW pracy przedstawiono mozliwości detekcji uszkodzeń w lotniczych konstrukcjach powłokowych z wykorzystaniem fal sprężystych. Omówiono kilka strategii detekcji uszkodzeń. Przedstawiono wyniki symulacji numerycznych z wykorzystaniem metody spektralnych elementów skończonych, jak również wynik badań eksperymentalnych z zastosowaniem wibrometrii laserowej.
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Bioindicative potential of shell abnormalities occurring in the clam Macoma balthica (L.) from the Baltic Sea
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Annealing Rate as a Crucial Parameter Controlling the Photoelectrochemical Properties of AuCu Mosaic Core–Shell Nanoparticles
PublikacjaThermal processing is an essential step during the synthesis of various metal nanostructures and for tailoring their morphology, optical, and electrochemical properties. Herein, a profound impact of the annealing rate and time on photoactivity of gold–copper nanostructures by changes in the position and alignment of energy levels and surface states is reported. AuCu nanoparticles (NPs) are fabricated by sputtering of thin metal...
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On dynamics of flexible branched shell structures undergoing large overall motion using finite elements
PublikacjaZaprezentowano autorski algorytm do analizy dynamicznej powłok sprężystych oparty na niejawnym schemacie Newmarka. Rozważania dotyczą całkowania po czasie dynamicznych równań ruchu sformułowanych w ramach nieliniowej sześcioparametrowej teorii powłok. Opracowanie zawiera pewne elementy analizy statycznej, poprzedzającej badania dynamiczne. Przykłady numeryczne prezentują zastosowanie algorytmu stanowią podstawową część pracy.
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Corrosion-erosion damage of heat exchanger tubes by desalted crude oil flowing at shell side.
PublikacjaRurki wymiennika zostały uszkodzone lokalnie przez odsoloną ropę naftową przepływającą pod ciśnieniem 2,6 MPa i w temperaturze 385-395K. Większość powierzchni rurek nie była uszkodzona i była pokryta osadem związków organicznych i nieorganicznych, zabezpieczającym przed uszkodzeniami. Badania wykluczyły możliwość występowania intensywnej korozji elektrochemicznej na powierzchniach rurek pozbawionych osadu. Przyczyną perforacji...
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A higher order transversely deformable shell-type spectral finite element for dynamic analysis of isotropic structures
PublikacjaThis paper deals with certain aspects related to the dynamic behaviour of isotropic shell-like structures analysed by the use of a higher order transversely deformable shell-type spectral finite element newly formulated and the approach known as the Time-domain Spectral Finite Element Method (TD-SFEM). Although recently this spectral approach is reported in the literature as a very powerful numerical tool used to solve various...
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Thermodynamic and geometrical characteristics of mixed convection heat transfer in the shell and coil tube heat exchanger with baffles
PublikacjaThe article presents passive heat transfer enhancement method in the form of baffles to increase the energy efficiency of the shell coil heat exchanger. Conducted literature review shows that, despite numer- ous studies, there is little work on the intensification of heat transfer at the shell side. Most of the work focuses on the impact of geometrical parameters of the coil itself. This article successfully proves that it is possible...
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Recent Achievements in Constitutive Equations of Laminates and Functionally Graded Structures Formulated in the Resultant Nonlinear Shell Theory
PublikacjaThe development of constitutive equations formulated in the resultant nonlinear shell theory is presented. The specific features of the present shell theory are drilling rotation naturally included in the formulation and asymmetric measures of strains and stress resultants. The special attention in the chapter is given to recent achievements: progressive failure analysis of laminated shells and elastoplastic constitutive relation...
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Equivalent 4-node enhanced assumed strain and hybrid stress shell elements in 6-parameter theory
PublikacjaWe discuss the equivalence of semi-enhanced assumed strain (EAS) and semi-hybrid stress (SEM) shell finite elements. We use the general nonlinear 6-field shell theory with kinematics composed of generalized displacements composed of the translation field and the rotation field. Due to the presence of rotation tensor the elements have naturally six nodal engineering degrees of freedom. We propose interpolation for a strain field...
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Experimental and numerical investigation on shell and coil storage unit with biodegradable PCM for modular thermal battery applications
PublikacjaThermal energy storage (TES) in automotive applications is currently growing in importance. TES can visibly reduce primary energy consumptions, decrease CO2 emission, and improve thermal comfort in electric as well as hybrid vehicles. However, to meet the new ambitious target (15% reduction of CO2 emissions in the new cars until 2025) it is required to use plug-in electric vehicles. For this reason, this paper focuses on the optimization...
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Generalized Taylor formula and shell structures for the analysis of the interaction between geosythetics and engineering structures of transportation lines
PublikacjaThe analysis of the interaction between geosynthetics and engineering structures (e.g. railroad bed, soil foundation, pipeline) assumes that the geosynthetic form elastic membranes or shell laid on different types of foundations. The mathematical description of that problems in continuous domain employs Laplace operator Δ or d’Alembert operator □. In this paper we demonstrate the analysis based on generalize Taylor formula, and...
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Core-shell cobalt particles Co@CoO loaded on nitrogen-doped graphene for photocatalytic water-splitting
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Core/shell structured Ti/Si/C composite for high-performance zinc-ion hybrid capacitor
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Numerical analysis of influence of intermediate stiffeners setting on the stability behaviour of thin-walled steel tank shell
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Recycling of Plastic Wastes for the Mass Production of Yolk–Shell-Nanostructured Co3O4@C for Lithium-Ion Batteries
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Influence of different types of the internal system of the ballistic helmet shell on the thermal insulation measured by a manikin headform
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Recycling of Plastic Wastes for the Mass Production of Yolk–Shell-Nanostructured Co3O4@C for Lithium-Ion Batteries
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Adsorption of cationic dyes onto Fe@graphite core–shell magnetic nanocomposite: Equilibrium, kinetics and thermodynamics
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MARSTRUCT benchmark study on nonlinear FE simulation of an experiment of an indenter impact with a ship side-shell structure
PublikacjaThis paper presents a benchmark study on collision simulations that was initiated by the MARSTRUCT Virtual Institute. The objective was to compare assumptions, finite element models, modelling techniques and experiences between established researchers within the field. Fifteen research groups world-wide participated in the study. An experiment involving a rigid indenter penetrating a ship-like side structure was used as the case...
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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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Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties
PublikacjaIn this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength...
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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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Multi-functional monodispersed SiO2-TiO2 core-shell nanostructure and TEOS in the consolidation of archaeological lime mortars surfaces
PublikacjaArchaeological traditional lime mortars are susceptible to many environmental conditions such as the impact of water (rain, humidity, groundwater, etc.), variation of temperatures' degrees, wind and/or pollution. Accordingly, this research aims to provide newly assessed multifunctional Nano-coating for the purpose of archaeological lime mortar protection. For this, the study combined physicochemical and mechanical characterizations...
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Experimental investigation of thermal energy storage in shell-and-multi-tube unit with nano-enhanced phase change material
PublikacjaThis paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled...
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Core/Shell Quantum Dots Encapsulated in Biocompatible Oil-Core Nanocarriers as Two-Photon Fluorescent Markers for Bioimaging
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New easy way preparation of core/shell structured SnO2@carbon spheres and application for lithium-ion batteries
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Defective TiO2 Core-Shell Magnetic Photocatalyst Modified with Plasmonic Nanoparticles for Visible Light-Induced Photocatalytic Activity
PublikacjaIn the presented work, for the first time, the metal-modified defective titanium(IV) oxide nanoparticles with well-defined titanium vacancies, was successfully obtained. Introducing platinum and copper nanoparticles (NPs) as surface modifiers of defective d-TiO2 significantly increased the photocatalytic activity in both UV-Vis and Vis light ranges. Moreover, metal NPs deposition on the magnetic core allowed for the effective separation...
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Removal of anionic dyes using magnetic Fe@graphite core-shell nanocomposite as an adsorbent from aqueous solutions
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Geometrically nonlinear FEM analysis of 6-parameter resultant shell theory based on 2-D Cosserat constitutive model
PublikacjaWe develop the elastic constitutive law for the resultant statically and kinematically exact, nonlinear, 6-parameter shell theory. The Cosserat plane stress equations are integrated through-the- thickness under assumption of the Reissner-Mindlin kinematics. The resulting constitutive equations for stress resultant and couple resultants are expressed in terms of two micropolar constants: the micropolar modulus Gc and the micropolar...