Multilayered Particles Research Articles

Scattering characteristics of dual counter-propagation high-order circularly symmetric Bessel beam by a multilayer chiral sphere

The interaction between dual counter-propagating high-order circularly symmetric Bessel beams (CSBBs) and multi-layered chiral particles is investigated. Within the framework of generalized Lorenz-Mie theory (GLMT), the distribution characteristics of the superposition of two beams are studied based on the vector superposition theorem. The near-field, internal field, and far-field radar cross section (RCS) of the dual-layered chiral sphere illuminated by dual CSBBs are obtained according to the boundary conditions. By comparing the results of RCS with those from the references for two cases: first, when CSBBs degenerate into plane waves incident on multi-layered chiral sphere, and second, when Bessel beams illuminate isotropic multi-layer sphere degenerated by chiral multi-layered sphere, the effectiveness of the principle and program exhibited here is confirmed. The impact of various parameters on the distribution of the superposed field, the near-field, internal field, and far-field RCS of the particles are analyzed in detail, such as the order, half-cone angle, incidence angle, and polarization angle. The research results in this paper provide theoretical assistance for understanding the interaction between dual CSBBs and non-uniform chiral multi-layered particles and have important value in realizing optical manipulation of complex chiral layered particles.

Evaluating the Impact of Sonication Process on Graphene Oxide Structural Properties

Graphene oxide (GO) is one of the members of carbon-based nanomaterials and can be featured as graphene structure decorated with various oxygenated functional groups. Recently, various methods have been found for producing carbon-based nanomaterials with enhanced efficiency in several applications. The chemical process involves oxidizing graphite to GO using a powerful oxidizing chemical. Hummers method is one of the most known and versatile method for the production of GO nanomaterials because of its ease of application, parameter controllability and high yield. This process enables graphite oxidation and exfoliation into single- or multi-layered GO sheets. Exfoliation, the separation of graphene or graphitic layers, is a critical process in GO synthesis. Since exfoliation separates multilayered graphite oxide flakes or particles, it forms single layer GO by forcing oxidizing agents or solvent molecules between layers. The sonication process can exfoliate the oxidized layers, resulting in the formation of GO structure when the exfoliated layers consist of only one or a few layers of carbon atoms. Therefore, sonication procedure is among the key parameters of Hummers method that influences the characteristics of GO-based nanomaterials. In this study, the impact of sonication duration time and power parameters on morphological and structural characteristics of GO development was examined. For this purpose, characterization studies were performed by using Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and Raman spectroscopy analysis. The findings revealed that the increase in sonication power and time led to an increase in defects in the resulting GO structure.

A population balance model for the kinetics of covalent organic framework synthesis.

This study presents a population balance model for the kinetics of nucleation and growth in covalent organic framework (COF) synthesis. The model incorporates second-order nucleation and first-order growth rates, consistent with proposals in the literature. Despite having non-linear terms, an implicit analytic solution is derived and then converted to explicit solutions for the monomer concentration and size distribution of COF flakes as a function of time. For experimental definitions of the induction time and the initial growth rate based on yield (y) vs time (t) curves, the model predicts power-law relationships: tind=0.409kN-1/3kG-2/3cA0-1 and dy/dtmax=0.965kN1/3kG2/3cA0, respectively. We discuss the implications for the interpretation of Arrhenius plots. We also discuss key discrepancies with experiments, including the predicted attainment of 100% yield instead of 30%-40% as observed and the value of the yield at the inflection point in the yield vs time curve. We suggest extensions to the model, including nucleation and growth kinetics with equilibrium solubility limitations and two-dimensional nucleation for the formation of multilayer COF particles.

Solid-lubrication performance of Ti3C2Tx - Effect of tribo-chemistry and exfoliation

Multi-layer Ti3C2Tx coatings have demonstrated an outstanding wear performance with excellent durability due to beneficial tribo-layers formed. However, the involved formation processes dependent on the tribological conditions and coating thickness are yet to be fully explored. Therefore, we spray-coated Ti3C2Tx multi-layer particles onto stainless steel substrates to create coatings with two different thicknesses and tested their solid lubrication performance with different normal loads (100 and 200 mN) and sliding frequencies (1 and 2.4 Hz) using linear-reciprocating ball-on-disk tribometry. We demonstrate that MXenes’ tribological performance depends on their initial state (delaminated few-layer vs. multi-layer particles), coating thickness, applied load and sliding frequency. Specifically, the best behavior is observed for thinner multi-layer coatings tested at the lower frequency. In contrast, coatings made of delaminated few-layer MXene are not as effective as their multi-layer counterparts. Our high-resolution interface characterization by transmission electron microscopy revealed unambiguous differences regarding the uniformity and chemistry of the formed tribo-layers as well as the degree of tribo-induced MXenes’ exfoliation. Atomistic insights into the exfoliation process and molecular dynamic simulations quantitatively backed up our experimental results regarding coating thickness and velocity dependency. This ultimately demonstrates that MXenes’ tribological performance is governed by the underlying tribo-chemistry and their exfoliation ability during rubbing.

Radiation force characteristics of non-uniform chiral stratified particles in standing wave field

<sec> <b>Objective</b> With the development of optical technology, the investigation of light-field-particle interactions has gained significant momentum. Such studies find widespread applications in optical manipulation, precision laser ranging, laser gas spectroscopy, and related fields. In optical manipulation techniques, employing two or more laser beams proves more effective for capturing and manipulating particles than using a single beam alone. In addition, with the increasing demand for manipulating particles with complex structures, it is necessary to conduct in-depth research on the radiation force characteristics of double Gaussian beams on non-uniform chiral particles. This research aims to deepen our understanding of how optical fields influence particles, thereby offering fresh perspectives in manipulating and utilizing non-uniform chiral layered particles on both a microscale and a nanoscale.</sec><sec> <b>Method</b> Based on the generalized Lorentz-Mie theory (GLMT) and spherical vector wave functions (SVWFs), the total incident field of a double Gaussian beam can be expanded by using the coordinate addition theorem. The incident field coefficient and scattering coefficient of each region of the multilayer chiral sphere are obtained by enforcing boundary continuity and employing multilayer sphere scattering theory. The radiation force acting on non-uniform chiral layered particles within a double Gaussian beam is then derived through application of the electromagnetic momentum conservation theorem.</sec><sec> <b>Results and Discussions</b> The theory and programs in this paper is compared with those in existing literature. The influence of various parameters on the radiation force is analyzed in detail, such as the incident angle, polarization angle, beam waist width, beam center position, and internal and external chiral parameters. These results indicate that compared with a single Gaussian beam, counter-propagating Gaussian standing waves exhibit significant advantages in capturing or confining inhomogeneous chiral layered particles, offering enhanced particle manipulation capabilities. Additionally, by selecting an appropriate polarization state of the incident light, a delicate balance can be achieved among these parameters, effectively stabilizing the capture of inhomogeneous chiral particles.</sec><sec> <b>Conclusions</b> This study employs the generalized Lorenz-Mie theory and the principle of electromagnetic momentum conservation to derive analytical expressions for the transverse and axial radiation forces exerted by dual Gaussian beams on multi-layered chiral particles propagating in arbitrary directions. The research provides an in-depth analysis of how standing wave beams affect the radiation force behavior of non-uniform chiral particles. Numerical analysis reveals significant influences of beam waist, particle size, chiral parameters, polarization angle and mode, as well as particle refractive index on both transverse and axial radiation forces. This research is important in analyzing and understanding the optical properties of complex-shaped multilayer biological cells and realizing the applications in the micromanipulation of multilayer biological structures.</sec>

In Ukrainian

The influence of the electronic subsystem of nanographene particles modified with titanium dioxide nanoparticles on the thermal destruction of the polymer matrix is analyzed. The variation in the conductivity of the modifiers made it possible to vary the effect of the metallic electronic system of graphene on thermal destruction by attenuating its effect through the transfer of energy to the electronic subsystem throughout the semiconductor film of anatase and excluding its effect on thermal destruction through a wide-band TiO2 dielectric of rutile form, which is opaque for energy transfer to the electronic subsystem. The application of such films does not affect the thermal processes in which the phonon subsystems of polymer, graphene and crystal modifiers are involved. The method of thermally programmable desorption mass spectrometry investigated the thermal destruction of hybrid composites of epoxy resin with graphene, namely the effect of surface modification of multilayer graphene particles by nanoparticles of pyrogenic titanium dioxide (anatase and rutile forms) on the thermal stability of hybrid epoxy composites in the temperature range of 40 − 800 °C. The activation energies Ed of destruction of atomic fragments of the polymer structure with the value m/z in the range of 16 ‒ 140 D were determined. It has been established that the thermal destruction of fragments of the polymer structure of epoxy resin composites with graphene modified with anatase and rutile forms of titanium dioxide is determined by the peculiarities of thermal transport at the polymer-modifier interfaces. Modification of graphene particles by the anatase form of titanium dioxide leads to increased thermal stability of polymer chains and cross-links in epoxycomposites in the entire range of m/z values of desorbed fragments. Filling the resin with graphene particles coated with the rutile form of TiO2 practically does not affect the intensity of thermal destruction of the composite matrix. The Ed values of different destruction fragments in composites with unmodified and modified graphene are in the range of 50 ‒ 130 kJ/mol. The value of Ed increases by 5 ‒ 10 kJ/mol when the resin is filled with graphene nanoparticles, while the coating of particles with titanium dioxide of the anatase and rutile phases practically does not change the value of Ed of the vast majority of fragments.

Direct imposition of the wall boundary condition for weakly compressible flows in three-dimensional smoothed particle hydrodynamics simulations

This study introduces a novel method for imposing wall boundary conditions in smoothed particle hydrodynamics (SPH). SPH is a particle method based on the Lagrangian approach, primarily employed in fluid analysis as a part of numerical computation methods. Due to its ability to discretize space using particles, SPH excels in handling analyses of free surface flow or multiphase flow with intricate boundary surfaces. However, there is a drawback in modeling wall boundaries using particles, as resolving the particle deficiency problem necessitates multi-layered boundary particles to be arranged behind the wall boundary. This leads to difficulties in implementing complex shapes and adds computational expense. To address this issue, this study suggests the use of boundary segments for wall boundary modeling and specifically employs triangular segments for three-dimensional expansions. For robust application of boundary conditions, a method considering both Poisson's equation and geometric configurations is proposed. The proposed method is independent of the segment density, which facilitates efficient and flexible modeling. In addition, by imposing accurate boundary conditions from the wall, the stability and accuracy of the solution are enhanced. The performance of the proposed method is validated through numerical examples, compared with various analytical and experimental results.

Study on the performance of spherical collision triboelectric nanogenerator

The development of the theoretical model for the spherical collision triboelectric nanogenerator (SC-TENG) has been slow, despite its ability to generate electric energy through low-frequency vibration while simultaneously reducing the motion response of the primary system. Previous theoretical models have solely focused on energy harvesting, disregarding the damping effect of spherical collisions. This paper presents an electromechanical coupling control equation, which accounts for the dynamic and electrical characteristics of spherical particles, to describe the relationship between motion displacement, velocity, acceleration, and particle number. The particle motion process is divided into two phases: non-collision and collision process. Using the constant velocity before and after collision, this paper calculates voltage and current changes corresponding to two collisions of particles in one cycle. Cadence software simulates and analyzes the equivalent circuit parameters of the TENG, where output voltage is proportional to the resistor/capacitor. Single, two, and three-particle acceleration, velocity, and displacement before and after collision are simulated using Abaqus software. Particle collision simulation shows the energy loss is related to the number of particles, the more the number of particles, the more the energy loss. The single-degree-of-freedom experimental model tests vibration reduction and energy collection effects of particles. As mass ratio increases, the vibration reduction and energy collection effects improve for particles. If the mass ratio remains constant, the vibration reduction effect does not vary much for different particle diameters (10/12/15 mm), but the energy collection effect of particle diameter of 10 mm is superior. Multi-layer particles, vibration control, voltage and current increase linearly with the number of layers. SC-TENG can be applied in the future to reduce structural vibration, while its additional energy collection capabilities can be as self-powered sensing to monitor movement of vibrating structures in real-time.

Optimization and experimental study of variable frequency intermittent stirring strategy for anaerobic digestion based on CFD

The stirring strategy has a significant effect on the efficiency of anaerobic digestion (AD). In this study, the suspension velocity of multi-layer blade particles was characterized based on CFD simulation, and a variable frequency intermittent stirring strategy was proposed to study the stirring effect and mixing energy consumption. Firstly, the fermentation cycle was divided into three parts, and three stirring speeds and mixing times were set for each part to carry out an orthogonal combination test. Taking methane production and mixing energy consumption as optimization indexes, a net energy output equation was established to optimize the new stirring strategy. The results showed that the new variable frequency intermittent stirring strategy could effectively improve digestion efficiency. This provides a theoretical basis for setting a stirring strategy in a biogas project.

Environmentally stable nanoscale superlubricity of multi-layered Ti3C2Tx MXene

With their two-dimensional layered structure, excellent mechanical behavior, and reduced interlayer sliding resistance, early transition metal carbides and nitrides (MXenes) have demonstrated promising solid lubrication properties at the macro- and nanoscale. Although MXenes can exist in several morphologies (multi-layer particles, clay, or single-to-few layer flake dispersions), the dependence of friction on the number of MXene layers is still yet to be fully understood. Here, we present number-of-layer-dependent friction property of single-to-four layer flakes of Ti3C2Tx MXene, produced using a modified MAX synthesis method, via atomic force microscopy with diamond-like-carbon and silicon probes at the nanoscale on silicon substrates. We demonstrate the superlubricity of single-layer Ti3C2Tx MXene as well as the effect of layers of Ti3C2Tx in an inert nitrogen atmosphere (coefficient of friction as low as 0.0039 ± 0.0006 for a bi-layer). Furthermore, we present the long-term stability of Ti3C2Tx's superlubricity up to a month in ambient conditions and up to three months in a vacuum environment. We believe that this investigation of layer-dependent and long-lasting MXene superlubricity at the nanoscale illustrates the potential of implementation of MXene into both space and industrial applications.

Multi-source term estimation based on parallel particle filtering and dynamic state space in unknown radiation environments

When hazardous sources threaten the environment, source term estimation is a crucial concern. Robotics provides a secure solution to the issue but still encounters challenges in uncertain environments. Rapidly inferring source parameters is a prerequisite for unmanned source search. However, when the number of sources exceeds one, the sensor can only measure the intensity of the coupled field. We propose a novel online multi-radiation source term estimation framework for autonomous source-searching tasks. The method incrementally constructs the state space of Bayesian estimation to adapt to diverse scenarios. Inspired by multi-sensor fusion and particle filtering, this framework employs multi-layer particles and updates them simultaneously to enhance the efficiency of fitting observations. Subsequently, the approach corrects (eliminate and randomly generate) the particles based on Poisson kriging interpolation to prevent particles in redundant layers from interfering with estimation. Furthermore, we compare the performances of our proposed algorithm with those in simulated and real experiments. Various metrics demonstrate that the suggested framework is accurate and robust.

Scattering of aggregated multi-layered biological cells by Bessel beams

Interactions between collective multi-layered cells and an off-axis high-order Bessel beam (HOBB) are investigated. The generalized Lorenz-Mie theory is applied to derive the expansion of HOBB. Based on the additional theorem, multiple scattering of collective multi-layered nanoparticles is obtained by considering the tangential continuous boundary conditions. The present theory and codes are proven to be effective by comparing with the simulations obtained from the computer simulation technology (CST) software. Numerical results concerning the effects of beam order, beam conical angle, spherical layer number, core radius and outer layer radius, outer layer refractive index and the spherical number on the scattering of various types of aggregated multi-layered particles are displayed in detail, which may provide critical support for analytically understanding the optical scattering characteristics of aggregated multi-layered biological cells of complex shapes and may find important applications in manipulating multi-layered biological structures.

EHD flow auxiliary particle collection in HVDC electrostatic precipitator based on PIV flow visualization technology

The electrostatic precipitator (ESP) is modified with the aid of an EHD flow in high voltage direct current (HVDC) to trap submicron-sized and ultra-high resistivity particles. In this study, the modified method for micron spherical silica was developed and optimized by particle image velocimetry (PIV) and numerical simulation. Meanwhile, scattering images of particle movement were obtained by laser and CCD camera. These results showed that the fine particles were driven by EHD flow towards the cavity. The D50 and D90 of particles measured by using the SYNC-type particle size analyzer inside the auxiliary dust removal cavity were 0.635 μm and 1.178 μm, which were much smaller than those of the particles deposited on the rear side of the cavity. The particle morphology was observed by scanning electron microscope (SEM), which indicated that multi-layer particles were agglomerating on the surface of the plate electrodes. However, particles were distributed in loose mono-layer in the cavity with no obvious agglomeration. The results showed that the modified method improved the efficiency.

Layer-by-Layer Particles Deliver Epigenetic Silencing siRNA to HIV-1 Latent Reservoir Cell Types.

For over two decades, nanomaterials have been employed to facilitate intracellular delivery of small interfering RNA (siRNA), both in vitro and in vivo, to induce post-transcriptional gene silencing (PTGS) via RNA interference. Besides PTGS, siRNAs are also capable of transcriptional gene silencing (TGS) or epigenetic silencing, which targets the gene promoter in the nucleus and prevents transcription via repressive epigenetic modifications. However, silencing efficiency is hampered by poor intracellular and nuclear delivery. Here, polyarginine-terminated multilayered particles are reported as a versatile system for the delivery of TGS-inducing siRNA to potently suppress virus transcription in HIV-infected cells. siRNA is complexed with multilayered particles formed by layer-by-layer assembly of poly(styrenesulfonate) and poly(arginine) and incubated with HIV-infected cell types, including primary cells. Using deconvolution microscopy, uptake of fluorescently labeled siRNA is observed in the nuclei of HIV-1 infected cells. Viral RNA and protein are measured to confirm functional virus silencing from siRNA delivered using particles 16 days post-treatment. This work extends conventional particle-enabled PTGS siRNA delivery to the TGS pathway and paves the way for future studies on particle-delivered siRNA for efficient TGS of various diseases and infections, including HIV.

Modified multipoles in photonics

Multipole decomposition method is a promising tool for investigation of radiating or scattering responses of electromagnetic sources or particles. It works even in the case of relatively complicated and compound scatterers like multilayer particles, clusters, or asymmetrical systems. Commonly, the radiation fields of point electric or magnetic sources are decomposed only into electric or magnetic dipole moments, while real sources can be described by a series of multipoles, including higher multipoles and toroidal moments. In this paper, we introduce the concept of modified multipoles describing real sources of electric, magnetic, and toroidal types. Using the analytical expressions of first-order multipoles, we discuss how they depend on the position of the center of radiation, as well as on the shift of the source, relative to the center of coordinates. We present results of multipoles for the sources with defects and asymmetry. The long-awaited question about distinguishing radiation patterns of electric and toroidal dipole moments in a far-field zone is discussed and solved in this paper. We show that radiation patterns of shifted electric and toroidal dipoles can be rotated to different angles relative to each other due to shifting. Moreover, we discuss modified anapoles. Our modified dipole approach will be useful for multipole analysis of complex systems in photonics such as nanoparticle clusters, metamaterials, and nanoantennas, as well as for better understanding issues of toroidal electrodynamics.

Nickel oxide morphology synthesized with a hydrothermal method for inverted perovskite solar cells.

In this paper, a hydrothermal method is used to synthesize a nickel oxide nanostructure (nano-NiO) for its application to inverted perovskite solar cells. These pore nanostructures were employed to increase both the contact and channel between the hole transport and perovskite layers of an ITO/nano-N i O/C H 3 N H 3 P b I 3/P C B M/A g device. The purpose of this research is twofold. First, three different nano-NiO morphologies were synthesized at temperatures of 140°C, 160°C, and 180°C. Then, a Raman spectrometer was used to check the phonon vibration and magnon scattering characteristics after an annealing temperature of 500°C. Second, nano-NiO powders were dispersed in isopropanol for subsequent spin coating on the inverted solar cells. The nano-NiO morphologies were multi-layer flakes, microspheres, and particles at synthesis temperatures of 140°C, 160°C, and 180°C, respectively. When the microsphere nano-NiO was used as the hole transport layer, the perovskite layer had a larger coverage of 83.9%. The grain size of the perovskite layer was analyzed by x-ray diffraction, and strong crystal orientations of (110) and (220) peaks were found. Despite this, the power conversion efficiency could affect the promotion, which is 1.37 times higher than the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate element conversion efficiency of the planar structure.

Bulk substitution of F-terminations from Ti3C2Tx MXene by cation pillaring and gas hydrolysation

Applications of 2D MXenes are limited by the difficulty of controlling bulk termination groups after the initial HF etching step without forming surface oxides. Here, we report on gas hydrolysation using a continuous flow of Ar (g) with a controlled partial pressure of H2O (g) as a new method to change the terminations of multilayered Ti3C2Tx MXene particles (T = O, OH and F), and demonstrate pre-intercalation of cations as a necessity for successful hydrolysation as it enables water molecules to enter the Ti3C2Tx MXene structure. Hydrolysation of pristine HF-etched Ti3C2Tx shows no compositional change before oxidation into a TiO2/C composite starts at T > 300 ˚C. However, by pre-intercalating various cations into the MXene, a pillaring of the structure is achieved, which for certain cations (K+ and Na+) remains even after hydrolysation at 300 ˚C. By hydrolysing K-intercalated Ti3C2Tx at 300 ˚C, a significant bulk F reduction of 78 % was achieved, accompanied by a comparable increase in O content and insignificant surface oxidation of the particles. For other cations (Mg2+, Li+ and TBA+) the expanded interlayer spacing collapsed upon hydrolysation, resulting in no significant compositional changes. Moreover, hydrolysation is shown to give higher selectivity towards F removal compared to air annealing, which instead resulted in the oxidation of C to CO2 and the formation of TiOF2. In Li-ion battery half cells, the intercalation of K-ions reduces both the capacity and energy efficiency compared to pristine Ti3C2Tx. Nevertheless, hydrolysation increases the capacity and intercalation voltage, and is thus a feasible method to control the electrochemical performance of Ti3C2Tx MXene. In summary, gas hydrolysation is demonstrated as a selective and efficient method to substitute F terminations with O-related terminations in multilayered MXene particles and pave the way for utilisation on other MXene compositions.

Composite polymer electrolytes with ionic liquid grafted-Laponite for dendrite-free all-solid-state lithium metal batteries.

Composite polymer electrolytes (CPEs) with high ionic conductivity and favorable electrolyte/electrode interfacial compatibility are promising alternatives to liquid electrolytes. However, severe parasitic reactions in the Li/electrolyte interface and the air-unstable inorganic fillers have hindered their industrial applications. Herein, surface-edge opposite charged Laponite (LAP) multilayer particles with high air stability were grafted with imidazole ionic liquid (IL-TFSI) to enhance the thermal, mechanical, and electrochemical performances of polyethylene oxide (PEO)-based CPEs. The electrostatic repulsion between multilayers of LAP-IL-TFSI enables them to be easily penetrated by PEO segments, resulting in a pronounced amorphous region in the PEO matrix. Therefore, the CPE-0.2LAP-IL-TFSI exhibits a high ionic conductivity of 1.5 × 10-3 S cm-1 and a high lithium-ion transference number of 0.53. Moreover, LAP-IL-TFSI ameliorates the chemistry of the solid electrolyte interphase, significantly suppressing the growth of lithium dendrites and extending the cycling life of symmetric Li cells to over 1000 h. As a result, the LiFePO4||CPE-0.2LAP-IL-TFSI||Li cell delivers an outstanding capacity retention of 80% after 500 cycles at 2C at 60 °C. CPE-LAP-IL-TFSI also shows good compatibility with high-voltage LiNi0.8Co0.1Mn0.1O2 cathodes.

Efficient progressive algorithm for light scattering of a multilayered concentric nanoparticle.

An efficient progressive methodology is presented for the computation of multi-scattering of electromagnetic waves by a multilayered concentric nanoparticle. Instead of solving a large set of system equations as reported in other works, the proposed approach utilizes a progressive algorithm which considers two adjacent shell layers at a time, marching progressively from the innermost to the outmost layer, and requires only multiplication of 4×4 matrices. The progressive algorithm yields the analytical expression for the scattering parameter of the concentric particle. Moreover, the progressive algorithm allows the scattering coefficients of a specific internal layer to be computed selectively, rather than having to calculate those of all layers of the entire particle as required by other algorithms. We show that the presented progressive method has equivalent accuracy to the well-known recursive algorithm, but it is more attractive due to its lower complexity in implementation. It is shown that light scattering of both a single solid sphere and two-layered concentric shell are special cases of the proposed methodology. Case study demonstrates that the presented methodology is useful in assisting the design of a multilayered core/shell structure with maximum forward scattering feature, indicating it is applicable to the exploration of optical phenomena of nanoparticles with numerous layers. Moreover, the present progressive algorithm is further extended to the electromagnetic scattering by an eccentric multilayered particle with inner cores displaced along a line defined by the centers of the spheres, which provides extra freedoms for the design of optical core shell spherical particles.

Dynamic Response of Components Containing Polymer Composites in the Resonance Region for Vibration Amplitudes up to 5g.

This paper focuses on high-speed-operation textile machines with the aim of increasing the rotational speed by operating within the resonance region to vibration amplitudes up to 5g. The native design does not allow keeping the vibration amplitude under 5g, which is a safe operation mode, for revolutions more than 120,000 min-1. The innovative modification of the design was made by the incorporation of polymer composite materials with carbon dust, glass hollow microspheres, and silica sand fillers to the rotor-bearing casing; moreover, through the incorporation of a multilayered foam composite structure and particle damper to the pressure plate of the mechanical machine system. By using the approach of supplementing with high-damping composites, the existing native design can be used, thus avoiding the costly production of new components and subassemblies with modified shapes and dimensions. Twelve possible combinations of mentioned modifications were tested, evaluated and compared with the native design made of steel, as standard structure material in mechanical engineering. The average vibration amplitudes were evaluated in the region before the resonance peak and in the range of the resonance peak, i.e., 120,000-135,000 min-1. Significant vibration amplitude reductions in the range from 30 to 70% of the average vibration amplitude were obtained. The vibration amplitude reduction results were evaluated considering the mass through the amplitude reduction efficiency coefficient.