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Search results for: SPHERICAL MICRORESONATORS
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Magnetic switching of Kerker scattering in spherical microresonators
PublicationMagneto-optical materials have become a key tool in functional nanophotonics, mainly due to their ability to offer active tuning between two different operational states in subwavelength structures. In the long-wavelength limit, such states may be considered as the directional forward- and back-scattering operations, due to the interplay between magnetic and electric dipolar modes, which act as equivalent Huygens sources. In this...
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Kinedynamics of Spherical Wavefields in Fluid and Dielectric Continua
PublicationDistubances induced by physical sources in fluids or dielectrics maintain their primary character while propagating throughout either of these bi-dynamic continua. The paper defines and illustrates four sets of bi-fields based on four specific fundamental kinedynamic solutions to inhomogeneous wave equations related to quasi-point acoustic and electromagnetic sources.
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Recurrence and differential relations for sphericial spinors
PublicationPraca zawiera zestawienie kilkudziesięciu relacji rekurencyjnych i różniczkiowych, spełnianych przez spinory sferyczne (harmoniki sferyczne dla spinu 1/2).
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Viscoelastic lubrication on spherical slide bearing in impulsive unsteady motion.
PublicationNiniejsza praca przedstawia numeryczne i semi-analityczne wyznaczanie składowych wektora prędkości lepkosprężystego oleju, oraz wartości ciśnienia hydrodynamicznego i sił nośnych w sferycznym łożysku ślizgowym o zmieniającej się w czasie niesymetrycznej szczelinie smarnej podczas nieustalonego impulsywnego smarowania. Łożyska ślizgowe o czopach kulistych występują w maszynach transportowych w celu lepszego manewrowania ustawieniem...
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Synthesis Methods and Favorable Conditions for Spherical Vaterite Precipitation: A Review
PublicationVaterite is the least thermodynamically stable anhydrous calcium carbonate polymorph. It exists very rare in nature, e.g. in some rock formations or as a component of biominerals produced by some fishes, crustaceans or birds. Synthetic vaterite particles are proposed as carriers of active substances in medicines, additive in cosmetic preparations as well as adsorbents. Also, their utilization as a pump for microfluidic flow is...
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Ground-State Entanglement Properties of Helium Atom in a Finite Spherical Cavity
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Resonance Frequency Calculation of Spherical Microstrip Structure Using Hybrid Technique
PublicationIn this paper the spherical microstrip structure is considered. The structure is composed of a metallic patch with an arbitrary shape placed on a dielectric coated metallic sphere. In the analysis the hybrid technique is utilized. In this approach the finite-difference technique is applied in a cavity model to determine the current basis functions on the patch. Next, using method of moments, the resonance frequency of the structure...
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Analysis of a caustic formed by a spherical reflector: Impact of a caustic on architectural acoustics
PublicationFocusing sound in rooms intended for listening to music or speech is an acoustic defect. Design recommendations provide remedial steps to effectively prevent this. However, there is a category of objects of high historical or architectural value in which the sound focus correction is limited or even abandoned. This also applies to indoor or outdoor concert shells, installations for teaching and acoustic presentations, etc. The...
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Optimized Stress and Geometry Control of Spherical structures under Lateral Loadings
PublicationIn this paper, a numerical model of a double-layer spherical structure has been examined under lateral loadings. When the structure has been distorted due to loadings, the dislocated joints have been moved to their original positions utilizing the adjustment techniques based on the force method. Meanwhile, the members’ internal forces were kept in the desired domain. Optimization techniques were also implemented in order to minimalize...
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Bifunctional catalyst based on molecular structure: Spherical mesoporous TiO2 and gCN for photocatalysis
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Electrodes Based on a Titanium Dioxide Nanotube–Spherical Silver Nanoparticle Composite for Sensing of Proteins
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Fermented juices as reducing and capping agents for the biosynthesis of size-defined spherical gold nanoparticles
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Fabrication of 3D graphene/MoS2 spherical heterostructure as anode material in Li-ion battery
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Facile synthesis N-doped hollow carbon spheres from spherical solid silica
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Optimal reshaping and stress controlling of double-layer spherical structures under vertical loadings
PublicationOptimal reshaping and stress controlling of double-layer spherical structures under vertical loadings
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Resonance Frequency Calculation of a Multilayer and Multipatch Spherical Microstrip Structure Using a Hybrid Technique
PublicationThis communication offers a rigorous analysis of the resonance frequency problem of a spherical microstrip structure mounted on a multilayer, dielectric-coated metallic sphere, with an electrically small radius. The structure consists of single or multiple metallic patches with arbitrary shapes. A full-wave analysis is employed with the use of proposed hybrid approach, combining the finite-difference technique with a spectral domain...
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Deformation of an elastic second gradient spherical body under equatorial line density of dead forces
PublicationWe consider deformations of an elastic body having initially a spherical shape. Assumed deformation energy depends on the first and second gradient of displacements. We apply an equatorial line density of dead loads, that are forces per unit line length directed in radial direction and applied along the equator of the sphere. We restrict ourselves our analysis to the case of linearized second strain gradient isotropic elasticity...
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Precipitation of Spherical Vaterite Particles via Carbonation Route in the Bubble Column and the Gas-Lift Reactor
PublicationSpherical 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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Hybrid super‐twisting fractional‐order terminal sliding mode control for rolling spherical robot
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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Comparative DEM calculations of fracture process in concrete considering real angular and artificial spherical aggregates
PublicationArtykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych (DEM). Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. Zbadano wpływ kształtu kruszywa na proces pekania i na zalezność obciązenia od ugięcia. Wyniki dwuwymiarowe i trzywymiarowe porównano bezpośrednio z doświadczeniami. Wyniki pokazały duzy wpływ kształtu kruszywa na wyniki numeryczne.
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Using Minimum Actuators to Control Shape and Stress of a Double Layer Spherical Model Under Gravity and Lateral Loadings
PublicationSpherical domes are picturesque structures built in developed countries to attract tourists. Due to horizontal and vertical overloading, the structures’ attractive shapes may be disturbed, and some members' stress may exceed the elastic level. In this paper, the shape and stress of a deformed double-layer spherical numerical model due to simultaneous lateral and vertical loadings are controlled, meanwhile, the number of actuators...
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Free-standing TiO2 nanotubes decorated with spherical nickel nanoparticles as a cost-efficient electrocatalyst for oxygen evolution reaction
PublicationHere, we report significant activity towards the oxygen evolution reaction (OER) of spherical nickel nanoparticles (NPs) electrodeposited onto free-standing TiO2 nanotubes (TNT) via cyclic voltammetry. It has been shown that simple manipulation of processing parameters, including scan rate and number of cycles, allows for formation of the NPs in various diameters and amounts. The polarization data with respect to transmission electron...
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Decision Support in Selecting a Reliable Strategy for Sustainable Urban Transport Based on Laplacian Energy of T-Spherical Fuzzy Graphs
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Acetate-Induced Disassembly of Spherical Iron Oxide Nanoparticle Clusters into Monodispersed Core−Shell Structures upon Nanoemulsion Fusion
PublicationIt has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA−IONPs) with the etyltrimethylammonium (CTA+) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange...
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Application of the Fröbenius method to the Schrödinger equation for a spherically symmetric potential: an anharmonic oscillator
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Badania teoretyczne łożysk ślizgowych podpartych na czaszy kulistej = Theoretical tests of hydrodynamic journal bearing with self-aligning spherical support
PublicationPrzedstawiono metodykę badań teoretycznych i doświadczalnych łożysk ślizgowych podpartych na czaszy kulistej. Badania teoretyczne prowadzono z wykorzystaniem programu komputerowego MES oraz programu wyznaczającego charakterystyki filmu olejowego. W celu opisu systemu tribologicznego łożysko-podpora stworzono trójwymiarowy model MES łożyska i gniazda. W czasie badań analizowano wpływ wielu czynników mogących ułatwiać lub utrudniać...
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Identification of sustainable trypsin active‐site inhibitors from Nigrospora sphaerica strain AVA‐1
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Unsteady periodic pressure and capacity for viscoelastic lubrication in spherical hip joint. Nieustalone okresowe ciśnienie i nośność w lepkosprężystym smarowaniu sferycznego stawu biodrowego.
PublicationNiniejsza praca przedstawia obliczenia numeryczne rozkładu wartości ciśnienia i siły nośnej podczas hydrodynamicznego smarowania w szczeliny stawu biodrowego człowieka przy uwzględnieniu okresowego ruchu niestacjonarnego oraz lepkosprężystych właściwości cieczy synowialnej, zmieniających się w czasie. Takie właściwości cieczy synowialnej nie były uwzględniane w dotychczasowych pracach naukowych przy modelowaniu numerycznym stawu...
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Evaluation of physical indicators and tool wear during grooving of spheroidal cast iron with a novel WCCo/cBN (BNDCC) inserts
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Cure Index demonstrates curing of epoxy composites containing silica nanoparticles of variable morphology and porosity
PublicationAn image was taken by Cure Index on curability of epoxy with silica nanoparticles having variable morphology and porosity. Three kinds of silica nanoparticles with non-porous curved-rod, non-porous spherical, and mesoporous spherical microstructures were synthesized and characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM) and Brunauer–Emmett–Teller analyses. Epoxy nanocomposites containing...
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X-Ray diffraction of the metallic nanostructures
Open Research DataMetallic nanostructures (gold and silver) were manufactured as a thermal annealing of gold or silver thin film. Gold films with thickness of 2.8 nm were deposited on a silicon substrates using a table-top dc magnetron sputtering coater (EM SCD 500, Leica), equipped with quartz microbalance for in-situ thickness measurements. Films were deposited from...
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A higher order transversely deformable shell-type spectral finite element for dynamic analysis of isotropic structures
PublicationThis 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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Calculation methods of interaction of electromagnetic waves with objects of complex geometries
PublicationModeling of the electromagnetic interaction with different homogeneous or inhomo-geneous objects is a fundamental and important problem. It is relatively easy to solve Maxwellequations analytically when the scattering object is spherical or cylindrical, for example. How-ever, when it loses these properties all that is left for us is to useapproximation models, to ac-quire the solution we need. Modeling of complex, non-spherical,...
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The Effect of Protrusions on the Initiation of Partial Discharges in XLPE High Voltage Cables
PublicationThis paper is focusing on 3D Finite Elements Analysis (FEA) based modelling of protrusions as defects or imperfections in the XLPE high voltage cable. This study is aiming to examine the impact protrusions have on the initiation of partial discharges. Spherical and ellipsoidal protrusions with different sizes at the conductor screen of the high voltage cable is an essential content of this paper. In addition, a spherical gas-filled...
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Efficient Fabry-Perot Open Resonator Analysis by the use of a Scattering Matrix Method
PublicationIn this paper a comparative study of the computational efficiency of two modeling methods applied to the analysis of the plano- and double-concave Fabry-Perot open resonators is presented. In both numerical approaches, a scattering matrix method was applied, which allows splitting the analysis of the resonator into several sections, including the one with a spherical mirror, which requires the largest computing resources. Two modeling...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublicationA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Thermal ablation modeling via bioheat equation
PublicationWe consider Pennes’ bioheat equation and discuss an implicit numerical scheme which has better stability properties than other approaches. Our discussion concerns Carthesian geometry problems, however it carries over to spherical geometry models and more complicated shapes.
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Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles
PublicationNowadays, more than ever, environmental awareness is being taken into account when it comes to the design of novel materials. Herein, the pathway to the creation of a colloid of spherical, almost purely metallic nickel nanoparticles (NPs) through pulsed laser ablation in ethanol is presented. A complex description of the colloid is provided through UV-vis spectroscopy and dynamic light scattering analysis, ensuring insight into...
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Fundamentals of classical and analytical mechanics
PublicationThe book is a monographic description of the present attempt to Newtonian and Lagrangian mechanics. But also, it could be found as a supplementary educational material useful for the graduate courses in mechanics taken by students majoring in mechanical engineering, physics or physical science. In the book you can find a brief introduction to concepts and principles of algebra of vectors; Kinematics of particles, mainly focused...
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GENERAL DYNAMIC PROJECTING OF MAXWELL EQUATIONS
PublicationA complete – system of Maxwell equations is splitting into independent subsystems by means of a special dynamic projecting technique. The technique relies upon a direct link between field components that determine correspondent subspaces. The explicit form of links and corresponding subspace evolution equations are obtained in conditions of certain symmetry, it is illustrated by examples of spherical and quasi-one-dimensional waves.
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Discrete Modelling of Micro-structural Phenomena in Granular Shear Zones
PublicationThe micro-structure evolution in shear zones in cohesionless sand for quasi-static problems was analyzed with a discrete element method (DEM). The passive sand failure for a very rought retaining wall undergoing horizontal translation towards the sand backfill was discussed. To simulate the behaviour of sand, the spherical discrete element model was used with elements in the form of rigid spheres with contacts moments.
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Time-domine Dipole Fields in acoustic and Elektromagnetics
PublicationThe ultrawideband (UWB) radio technique presents a challenge not just for technology. The UWB carrier-free pulses act at a close distance, their electromagnetic fields being very different from classic monochromatic plane wave. The author proposes to adapt a time-domian approach to analysis of broadband spherical fields, both acoustic and electromagnetic, in fundamental cases of quasi-point physical sources.
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Resonant Frequencies in the Open Microstrip Structures Placed on Curved Surfaces
PublicationThe paper presents the research on open microstrip structures placed on curved surfaces such as cylindrical, elliptical or spherical. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields into suitable function series. Utilizing the continuity conditions the boundary problem is formulated which is solved with the use of method of moments. The investigated structures find application...
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Modal FEM Analysis of Ferrite Resonant Structures
PublicationThe finite-element method (FEM) is applied for modal analysis of ferrite-loaded spherical resonators. To improve the efficiency of the numerical calculations, the body-of-revolution (BOR) technique is utilized. Due to the frequency-dependent ferrite permeability, FEM leads to a nonlinear eigenvalue problem that is challenging to solve. To this end, Beyn’s method is proposed. The effectiveness of the proposed approach is confirmed...
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Discussion on “Coupled effective stress analysis of insertion problems in geotechnics with the Particle Finite Element Method” by L. Monforte, M. Arroyo, J.M. Carbonell, and A. Gens
PublicationAddressed here is the Particle Finite Element Method (PFEM) modelling of undrained CPTu penetration with regard to a reference analytical solution based on the Spherical Cavity Expansion Method (SCEM). Also discussed is the choice of the soil model and its parameters. The effect of cone interface friction on CPTu simulation is analyzed in a series of penetration tests using Arbitrary Lagrangian-Eulerian (ALE) and Updated Lagrangian...
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Improvement of electrochemical action of zinc-rich paints by addition of nanoparticulate zinc
PublicationThe influence of nanosized particles on electrochemical action of standard zinc-rich paints by means of SEM as well as potential and impedance measurements has been investigated. The motivation for doing this was to obtain additional electrical connection between the spherical microparticles themselves and zinc particles and steel substrate. Overall zinc content was at the level of 92% by weight. Samples with different concentration...
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PROBLEMS WITH CORROSION PROTECTION STEEL STACKS IN FGD SYSTEMS
PublicationThis paper presents problems associated with corrosion of steel stacks and changes in philosophy of corrosion protection when implemented into flue gas desulphurization systems. In-situ tests were taken by means of electrochemical impedance spectroscopy at a stack which discharges flue gas before wet lime/limestone desulphurization. A very rapid soaking of spherical infill vinylester coating with electrolyte has been observed....
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Oxide nanoparticle exsolution in Lu-doped (Ba,La)CoO3
PublicationThis study investigated Lu doping of Ba0.5La0.5CoO3 and its influence on the exsolution of oxide nanoparticles (NPs). As a result of Lu doping, we observed the phase segregation into the main Ba0.4La0.6Co0.85Lu0.15O3 (BLCO–Lu) phase and the secondary Ba0.85La0.15Co0.75Lu0.25O3 (BCO–Lu) phase. We noticed the exsolution of BCO–Lu nanoparticles on the main BLCO–Lu phase. Moreover, the BLCO–Lu phase exsolved in the form of nanoparticles...
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Action-reaction based synthesis of acoustic wavefield equations
PublicationThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...