Advanced Materials

StabilityStability in the course of exploitation and catalytic activity in reactions, taking place on the electrodes, are the most important characteristics of electrocatalystsElectrocatalysts that determine their application in fuel cells. Relationship of the electrochemical behavior of Pt/CPt/C and PtCu/C catalystsCatalysts with their morphology is studied in this chapter. In according with results of our study, Pt(Cu)/CPt(Cu)/C materials with core-shellCore-shell architecture of two-component nanoparticles can be a promising direction in electrocatalysis. Such materials can exhibit high specific characteristics, while being characterized by a reduced content of platinum and a low percentage of d-metal dissolution. The resulting Pt/CPt/C catalysts are characterized by surface area values from 11 to 80 m2/g(Pt), average crystallite size from 1.1 to 5.7 nm, mass fraction of platinum from 18 to 39% and relative stabilityStability during long-term stress testingStress testing of more than 70%, which is comparable to or exceeds this value for the commercial catalyst JM20.

In the present study, different carbon-supported platinumPlatinum nanomaterials were prepared using electrodeposition method and the influences of some organic additivesOrganic additives, such as potassium citrateCitrate, Nafion and polyvinylidene fluoride (PVDF)Polyvinylidene Fluoride (PVDF) on the morphologyMorphology, electrochemically active surface area (ESA) and electrocatalytic activity of platinumPlatinum nanomaterials (Pt/Vulcan XC-72) were evaluated. The materials were electrodeposited on a rotating disk electrode (RDE) from the electrolyte hexachloroplatinic acid (H2PtCl6) and H2SO4 in the absence and presence of the organic additivesOrganic additives. The materials obtained were characterized using powder X-ray diffraction, scanning electron microscopy, electrochemical methods. In addition, the electrocatalytic activity of the materials towards oxygen reduction reactions was evaluated by employing linear sweep voltammetry on RDE at 1000 rpm. The presence of the organic additivesOrganic additives increased the overpotential at the growth stage of the particles, leading to a decrease in the particle sizeParticle size and hence an increase in the ESA of platinumPlatinum nanoparticles from 19 to 43 m2/g(Pt) The electrocatalystsElectrocatalysts prepared using the different organic additivesOrganic additives have the following increasing order of electrochemical activities towards the ORROxygen Reduction Reaction (ORR) in an aqueous solution of HClO4: citrateCitrate < without the organic additivesOrganic additives < Nafion < PVDFPolyvinylidene Fluoride (PVDF) in the potential range of ca. 0.7–0.9 V. This electrochemical behavior can be attributed to the differences in the particle sizeParticle size, ESA, and the morphologyMorphology of the synthesized carbon-supported platinumPlatinum nanomaterials.

Study the atomic and electronic structure of polyacrylonitrile (PAN) during IR-annealing and the formation of Co/PAN nanocomposite based on a combination of computer simulation methods and X-ray absorption spectroscopy was carried out. Using the Density Functional Theory method, structural models of pure PAN and Co/PAN nanocomposite were obtained and electronic density of states was calculated. X-ray absorption spectra for the obtained structural models were calculated and showed good agreement with the experiment. The densities of states demonstrated that polymer form changes from non-conducting to conducting during annealing process.

Few-layer graphenesFew-layer graphenes and nanoscrollsNanoscrolls have been prepared by exfoliation of the triple graphite nitrate co-intercalation compoundTriple graphite co-intercalation compound (GNCC) as well as pre-thermally expanded GNCC in liquid media. Graphite nitrate sequentially co-intercalated with ethyl formate and acetic acid and thermally expanded graphite (TEG) obtained from it were used as precursors of carbon nanoparticlesCarbon nanoparticles. Ethanol, acetonitrile and a mixture of DMFA:H2O (9:1 by volume) were used as solvents for liquid phase exfoliation of GNCC and TEG assisted with sonication. The microstructure and morphology of obtained few-layer graphenesFew-layer graphenes and nanoscrolls were investigated by transmission electron microscopy (TEM). Planar sizes of the as-prepared few-layer graphenes reached several tens of μm and their thickness was within 1–10 atomic layers according to TEM data. Sonication regime effect on the resulting carbon nanoparticles morphology was studied. It was shown that sonication with a power of 70 W (42 kHz) provided obtaining of the few-layer graphene suspensions containing also single-layered graphene particles. The sonication with 315–630 W (22 kHz) leads to the formation of carbon nanoscrolls. It was found that ethanol is more preferable medium for carbon nanoparticles generation as compared to acetonitrile. Liquid phase exfoliationLiquid phase exfoliation of GNCC and pre-thermally expanded GNCC allows obtaining dispersions of carbon nanoparticles with various morphology—single- and few-layer graphenesFew-layer graphenes, nanoscrollsNanoscrolls as well as small graphene particles.

Micro- and nanostructures improved different surface properties, which is used in various fields of science and technology. It is of a great interest to develop the physical foundations of new effective methods for creation of such structures. The paper proposes a method of direct laser micro- andNanostructuring nanostructuringMicro- and nanostructuring based on nanosecond lasersNanosecond laser with radiation of UV and VUVUV and VUV range. The method allows surface laser treatment of materials with different physical properties: metallic alloys, ceramicsCeramic, diamond-like filmsDiamond-like film, semiconductors. Formation of surface micro and nanostructures on the surfaces of diamond-like filmDiamond-like film, germanium, aluminum oxide and zirconium bronze is demonstrated. A theoretical modelTheoretical model of nanostructure formation on solid surface melted by nanosecond laserNanosecond laser pulse is considered. Moreover, a simple model for formation of conical structures at laser ablation without melting is described.

Laser micro- andNanostructuring nanostructuringMicro- and nanostructuring is used in various fields of science and technology, because it can improve different surface properties. The chapter considers a method of direct laser micro- andNanostructuring nanostructuringMicro- and nanostructuring of metallic surfaces and an effect of such preliminary laser surface treatment on the mechanical properties of solid-phase joints made by diffusion weldingDiffusion welding. For laser treatmentLaser treatment it is proposed to use scanning beam of Nd:YAG laser with a wavelength of 355 nm. Analysis of surface topography of samples treated by nanosecond laser was performed by optical profilometer. After the diffusion weldingDiffusion welding tensile testsTensile tests were performed on conjunction samples cut out from welded workpieces. These tests showed that preliminary laser processing of the surface of samples made of nickel alloyNickel alloy leads to an improvement in the mechanical properties of the conjunction obtained by diffusion weldingDiffusion welding. It leads to an increase in the tensile strength up to 29% and tensile strain up to 20%. The pulse energy density at laser surface treatment significantly affects the properties of welded joint. Also the preliminary laser treatmentLaser treatment of surfaces allows one to reduce the temperature of diffusion weldingDiffusion welding.

The analysis of the initial stage of wear initiation in crystalline materials with a heterogeneous structureStructure under cyclic impact loadingCyclic impact loading is conducted. Wear under these conditions begins with the formation of fatigue defectsFatigue defects. Depending on the structure of the materialStructure of the material and loading conditions, they are formed as cracksCracks, pores or craters. A theoretical model is proposed for calculating the duration of their nucleationNucleation. The parameters of the model for its application in the conditions of droplet impingement erosionDroplet impingement erosion, in particular, under the influence of a discrete vapor-droplet flow, are considered and determined. The results of model calculations are presented in comparison with the experimental data of bench droplet tests for steel samples 20Cr13 with a sorbite structureStructure and samples with a vacuum ion-plasma coatingIon-plasma coating of the TiAlSi-system with a 3D-nanocompositeNanocomposite structureStructure. It is shown that under conditions of contact cyclic loads, the wear resistance of materials and coatings is primarily determined by structural parameters. Based on the presented calculation results and experimental data, the use of the proposed model for the design of wear-resistantWear-resistant materials and coatings is recommended. Experimental data on the development of wear of the ion-plasma TiAlSi-coatingIon-plasma TiAlSi-coating upon droplet impingement action are also presented. Chipping of the coating occurs by the formation of fragmented porous cracks.

The chapter presents a comprehensive analysis of the nanoindentationNanoindentation derived mechanical characteristics (elastic modulus and indentation hardness) of the TiN coatingCoating deposited using the method combining magnetron sputtering and arc evaporation on a steel substrate. For the nanoindentationNanoindentation experiments, spherical indenter was used. The results of studies of microstructureMicrostructure, chemical composition, and also measurements of the coatingCoating thickness using a focused ion beam on a scanning electron microscopeScanning Electron Microscope (SEM) are presented.

The sheet metalSheet metal forming process is a basic deformation method in the mechanical field. In particular, bending deformation processing is a universal processing method that is widely used to form sheet metal parts such as the aviation industry, shipbuilding, automotive and so on. During the sheet metalSheet metal bending process, the spring-backSpring-back and forming force are very important output parameters that need to be determined to ensure the accuracy and load capacity of machining equipment. To predict the spring-backSpring-back of V-bendingV-bending process for SS400 sheet materialSheet material, various hardening modelsHardening model have been imported into FEMFEM simulation software in order to predict and compare with corresponding experimental results of SS400 sheet materialSS400 sheet material. To simulate spring-backSpring-back of V-bendingV-bending, the deformed results of V-shapeV-shape from the forming simulation in Abaqus/ExplicitAbaqus/Explicit should be imported into Abaqus/StandardAbaqus/Standard, and then a static analysis will calculate the spring-backSpring-back of V-bendingV-bending. The results showed both hardening lawsHardening law were in good agreement with experimental results due to the thick sheet of material. Moreover, the forming forceForming force magnitude of V-bendingV-bending will vary according to machining conditions, geometric shapes of products, sheet materialsSheet material, etc. Then, this study verifies the effect of technological and geometric parametersGeometric parameter such as elevated temperatureElevated temperature, punch speed and sheet thickness to bending forceBending force when forming a V-shapeV-shape of SS400SS400 sheet material and selects the optimum parameters using TaguchiTaguchi design and ANOVAAnalysis of Variance (ANOVA) method.

This paper presents some numerical results of buckling analysisBuckling analysis of a folded laminate composite plateFolded composite plate using finite element methodFinite element method. The effects of fiber orientations, folding angle on buckling loads, and the corresponding mode shapes under in-plane loading condition were considered. Matlab programming using nine nodded rectangular isoparametric plate element with five degree of freedom per node based on Mindlin plate theory was built to solve the problems. A good agreement is found between the results of this technique and other published results available in the literature.

Nowadays, increasing productivity and quality of machining become major challenges of the metal cuttingMetal cutting process. Due to the complexity of the chip formation process at high cutting speeds, the finite element methodFinite element method (FEM) has been widely used as an approximate solution. In the metal cutting, the chip formation is essentially concerned with the large strains and the high strain rateStrain rates. In this chapter, two numerical models with and without strain rate effects are proposed. An appropriate model is then verified by comparing the simulated cutting forces under varying cutting parameters. The simulation model with strain rate is consistent with the experimental value, whereas the model without strain rate underestimates the cutting forces. The strain rate also modifies the cutting forces owing to the stresses that occurred at cutting regions and significantly affected by the strain rate.

In this research, a numerical model of temperature distribution in PCBN cutting toolsPCBN cutting tools in orthogonal turning 9XC hardened alloy steel was developed. The heat sources generated at cutting zones were determined by theoretical calculations. The temperature distribution in the cutting toolCutting tool, chip, and workpiece was found by using the heat transfer equations combined with finite elementFinite element analysis. The isotherms obtained from the numerical model are high compatible with those obtained from experimental measurements. The results indicate that the numerical model has satisfied the requirements and can be applied to similar machining conditions.

The article focuses on the separate and simultaneous influences of sealing technological effects: air temperature, sealing speed, roller pressure and nozzle pressure on resistance to water penetration, ultimate tensile strength, the adhesive strength of seam sealing after washed in processing sportwearsSportswears made from waterproof fabricsWaterproof fabrics. In this research, we used the analysis of variance method for two-elements case, planning method orthogonal experimental variety of factors, Microsoft Excel 2013 and Design Expert 11.0 software to process and analyse experiment results. The result which is to identify sealing technological elements has important effects on resistance to water penetration, ultimate tensile strength, the adhesive strength of seam sealing after washed. The result of this study is an useful guide in the actual production to improve the quality of links in order to save time and costs in the actual production in sportwear garment enterprises as well as Seam tapeSeam tape supplier in general and at TNG Investment and Trading Join Stock Company in particular.

The equations for the statistical operatorStatistical operator and the density matrixDensity matrix are considered here for a single particle and a system of identical particles when dissipative forces act on them. From the equation for the density matrix, a kinetic equationKinetic equation can be obtained when the density matrix is diagonal. These equations are the basis for the study of the simplest models of nanophysics.

The structural and electrophysical characteristics of a number of solid solutions of layered perovskite-like oxides Bi3−xLuxTiNbO9 (x = 0, 0.05, 0.1) have been studied. According to the data of powder X-ray diffraction, all the compounds are single-phase with the structures of two-layer Aurivillius phases)Aurivillius Phases (APs) (m = 2) with the orthorhombic crystal lattice (space group A21am). The temperature dependence of the relative permittivity ε/ε0(T) compounds have been measured and showed that the Curie temperature of the perovskite-like oxides Bi3−xLuxTiNbO9Bi3−xLuxTiNbO9 increases with the doping parameter x up to TC = 964 °C.

The two-stage pulsed laser depositionPulsed Laser Deposition (PLD) growth of thin InSbInSb films on (111) Si and on LiNbO3 YX-128° substrates was studied using a thin InSbInSb buffer layer deposited at a low temperature. This approach improves carrier mobility in InSbInSb base layer, which largely determines the sensitivity of IRIR photodetectorPhotodetectors at room temperature. The response speed in the near-IR range at λ = 985 nm was 1.92 ms, and the decay time was 1.67 ms, under xenon lamp radiation with mechanical modulation. The photosensitivity of the InSbInSb/(111) Si film was about 1 A/W at 293 K. The response time of the sample was~6.8 μs, the time of complete recovery was ~34.5 μs, under laser diode radiation with a wavelength of 840 nm, power 1 mW.

The chapter presents the results of studies of X-ray diffractionX-ray diffraction analysis, the temperature dependence of the permittivity, the frequency dependence of ε(T) and the absorption coefficientAbsorption coefficient of electromagnetic radiation in the frequency band 0.1–1.0 THz for samples of Sr0,61Ba0,39Nb2O6 ceramicsCeramic doped with rare-earth ions Ce, La, Nd, YbRare-earth ions Ce, La, Nd, Yb.

Universal technique is proposed in the work. The relationships for determining the intensity of the optical fieldsOptical field generated by the laser interference displacement meter based on a two-way laser interferometer with combined branches and implementing the method of highlighting the surface of the test object are described in detail. The proposed relations allow one to carry out computational and theoretical modeling and study of functional characteristics in the interests of creating new promising optical instruments for measuring the displacementsDisplacement measurement of the surfaces of objects under control.

The numerical model of the high-angle boundary is used for quantum-chemical calculations of the binding energy of atoms of impurity and alloying elements at the grain boundariesGrain boundaries in iron. Elements of the fourth period, from potassium to krypton, are considered as impurity. It is shown that the bond strength between grains is primarily determined by the type of atoms located at the boundaries. To a lesser extent, the bond strength depends on the details of the arrangement of atoms.

PolymerMicroscopy image enhancement compositesPolymer composite areMicrostructure compositeBottom ash particle materialsImage analysis with matrices of polymersPolymer with reinforcements using fibers or particles or both together. This study uses polypropylene polymer compositePolymer composite material with reinforcement of bottom ash particlesBottom ash particle. In the manufacture of polypropylene-shaped sheet (lamina) polymer compositePolymer composite materials with bottom ash particlesBottom ash particle, the process of assessing the composite characteristics of the polypropylene matrix such as the level of distribution of bottom ash particlesBottom ash particle as fillers in the polypropylene matrix through microscopic imagesMicroscopic image is necessary. Analysis of the level of distribution of reinforcement particle is used to avoid the formation of filler particle agglomerates during the dispersionDispersion of various types of fillers in polymerPolymer resins. Bottom ash particlesBottom ash particle themselves have an irregular shape that requires particular analysis to distinguish a single particle and an agglomerate particle. Before the analysis step, the most crucial step at the beginning is to carry out the process of improving the quality of the input imageImage, which aims to improve imageImage contrast and eliminate unwanted noiseNoise. This chapter proposes an image enhancementImage enhancement method to enhance the quality of the microstructure imageMicrostructure image of a polymer compositePolymer composite that is analyzed using a digital microscope. The proposed method combines the multiresolution approach and the anisotropic diffusion method. From the experiment, this image enhancementImage enhancement method gives the best performance when it is compared with other techniques in the state of the arts.

The chapter analyzes the effect of oil temperature and dynamic viscosity on hydrodynamicHydrodynamic pressurePressure distribution of the oil lubrication film in the internal gear motor and pumpInternal Gear Motor and Pump (IGMaP). The Reynolds equation with appropriate boundary condition is solved to obtain 2D hydrodynamic pressure distribution by using the finite difference method (FDM)Finite Difference Method (FDM). Numerical calculations point out that the oil temperature and viscosity have great effect on hydrodynamic pressure distributionPressure distribution as well as the maximum value of pressure.

With the rapid development of removal technology of materials, manufacturing methods of advanced materials with highly flexible shape has been improved. Electro-chemical machining (ECM)Electro-Chemical Machining (ECM) is one of the most advanced manufacturing methods for not only manufacturing the high hardness metal with flexible profiles, but also provides a better solution to surface roughness of finished products and rate of material removal in the comparison with other advanced manufacturing methodologies such as electric discharge machining (EDM). However, there are many parameters involving to the ECM process such as velocity of the electrode, pressure of water, voltage, frequency and pulse of the current. Therefore, a set of optimization parameters for machining process of a material type is necessary to provide the best solution in industrial applications. This research focuses on investigating an optimal set of process parameters of the ECM machine by using the surface response methodology (SRM). A database of process parameters is generated by machining and minimizing the surface roughness of the SS AISI 316 stainless steel via suing the copper electrode. Then, an objective function (or regression function) is generated by applying the SRM to the selected database. Finally, genetic algorithm is used to achieve the optimal process parameters. Experiments are implemented with achieved processing parameters to analyze and validate the proposed method.

This chapter used the TaguchiTaguchi experimental design method in order to study the surface roughness and vibration during thermal-assisted millingMilling of SKD11 steel.SKD11 steel The effect of cutting parametersCutting parameters such as cutting speed, feed rate, cutting depthCutting speed, feed rate, cutting depth and support elevated temperatures on the output data were evaluated. Multi-objective optimizationMulti-objective optimization for minimum both surface roughnessSurface roughness and vibrationVibration was also estimated to improve the cutting processCutting process. The optimal set of control parameters to achieve the minimum of surfaceSurface roughnessRoughness and vibration amplitudeVibration amplitude could be obtained as Vc = 280 m/min, f = 230 mm/min, t = 0.5 mm, T = 400 °C.

In mechanical manufacturing, the surface roughnessSurface roughness of a machined partMachined part is a significant parameter to evaluate the products’ quality, and as a result, it must be thoroughly measured. Many researches have been studied over the past few to reduce the inherent drawbacks, such as contact, off-line inspection, speed of limited measurement, in the conventional measurement system using contact method. In this paper, the feasibility of the contactless inspection of part surface roughnessSurface roughness using Microsoft Kinect v2Microsoft Kinect v2 have been demonstrated. The part roughness parameters have been estimated by using of PCAPrincipal Component Analysis (PCA) plane fittingPCA plane fitting on point cloud dataPoint cloud data. In addition, the results received with the Microsoft Kinect v2Microsoft Kinect v2 system are finally compared to those received with a stylus contact surface roughnessSurface roughness measurement system to verify the proposed approach within this paper.

The burned rocksBurned rocks of some mine dumpsMine dumps of the Rostov region are evaluated. The physicomechanical properties of the rocks as raw materials for the construction of the subgrade of the access railway track, the structural layers of pavement are investigated. The properties of fractioned gravel and crushing screeningsCrushing screenings from burned mine rocks are given. The features of hardening of the massif of a roadbed of burnt rocks of mine dumps are shown. The technology of the subgradeSubgrade and pavement layersPavement layers is described. The possibility of using materials from burned mine rocks in the construction of subgrade, the ground of roads and structural layers of pavement has been substantiated. The variants of pavement designs using materials from burnt rocks of mine dumps are considered. Practical work was done on the erection of the subgrade railway track and local technological roads, industrial sites and sidewalks. The successful operation of sections of the railway access road, technological roads and sidewalks confirms the feasibility of using burnt rocks of mine dumps in road construction. The use of mine dump rocksMine dump rocks allows us to solve some environmental problems: reduce the number of quarries in the extraction of natural raw materials, preserve the natural landscape of the earth’s surface, free land from dumps, and reduce pollution of water and air basins.

The paper deals with computer modelling in finite element software ACELAN-COMPOS of multiscale two-phase magnetoelectric (piezomagnetoelectric) bulk compositesMagnetoelectric composite that consist of piezomagnetic and/or piezoelectric fractions of irregular structures. The proposed technique is based on the models of micro- and nanoscale materials with interface or surface effects, the effective moduli method, the modelling of representative volumes, and the use of finite element technologies for solving the problems in the representative volumes.

Using the methods of effective moduli and finite elements, the effective properties of nanoporous thermoelastic transversely isotropic materials were studied for simple random and for closed structures of porosity. Nanoscale effects were modelled in the framework of the Gurtin-Murdoch model of interface stresses and of the high conductivity model. The modelling and solution of homogenization problems was performed in the ANSYS package, while structures of representative volumes with closed porosity were created in the ACELAN-COMPOS package. The effect of porosity, types of representative volumes and pore sizes on the values of the effective modules of nanoporous titanium is analysed.

The role of elastic moduli of the fourth order in the investigation of the dynamic characteristics of prestressed bodies made of materials that allow large static deformations is studied. The studies were carried out in the Lagrange coordinate system. Linearized defining relations and equations of motion of a prestressed medium are used, which allow us to consider nonlinear effects of the “second” and “third” orders. On the example of the problem of the propagation of shear harmonic oscillations, the influence of the initial stresses on the propagation velocity of surface wavesSurface waves is studied. Two, five, and nine constant models of a prestressed layer made of palladium-based bulk metal glass are considered. The results obtained in the framework of various models are compared. The difference of the effect of initial stresses on the velocities and critical output frequencies of the higher modes of surface wavesSurface waves, calculated with and without higher order moduliHigher order moduli, is shown. A significant effect of the magnitude of the initial stresses is established for uniaxial and biaxial initial stress statesInitial stress states.

The propagation of the surface wavesSurface waves in elastic media has been extensively studied and is very important in many fields. The Laplace domain Boundary Element Method (BEM) is powerful and accurate numerical method that can be employed for treating such problems. Since anisotropicAnisotropic elastic problems is very computationally challenging for any BEM formulation, the choice of particular numerical Laplace inversionLaplace inversion algorithm is crucial for efficient anisotropicAnisotropic elastodynamic Laplace domain boundary element analysis. In this investigation, for a specific problem of anisotropicAnisotropic linearly elastic half space subjected to transient loading, we examine two different methods for numerical inversionInversion of Laplace transformsLaplace transforms. The first method we test is the renowned Durbin’s methodDurbin’s method which is based on a Fourier series expansion. The second method is the convolution quadrature methodConvolution Quadrature Method (CQM) which is reformulated as a numerical Laplace transform inversionLaplace transform inversion routine. Methods are compared in the context of their application in the framework of Laplace domain collocation boundary element formulation.

InReflection thisTransformation chapterReflection, the problem of the diffractionDiffraction of ultrasonic waves by cavity obstacles in an infinite two-dimensional elastic medium with double reflectionsReflection is studied. A short pulse is introduced into the elastic medium with tonal filling with several periods of a plane high-frequency, monochromatic longitudinal or transverse elastic wave. Double re-reflectionsReflection of waves with any possible reflectionsReflection (longitudinal wave to longitudinal, transverse to transverse waves) and transformationsTransformation (longitudinal waves to transverse, transverse waves to longitudinal) are considered. The integral representations of the displacements in the reflected waves are written out on the basis of the physical theory of Kirchhoff diffractionDiffraction. An asymptotic estimate of multiple diffractionDiffraction integrals using the multidimensional stationary phase method gives an explicit form of the geometrical optical approximation of displacements in doubly reflected and transformed waves.

WaveWaves processes in topographic waveguidesTopographic waveguides are studied. A wedge-shaped waveguideWaveguides with a triple cross-section is considered. Hypotheses for variable stiffness plates are taken into account. Dispersion dependenciesDispersion dependencies for two orthotropic materialsOrthotropic materials for a modelModel of theTimoshenko model TimoshenkoTimoshenko type using the variational Hamilton-Ostrogradsky principle and the Ritz approximate calculation method are constructed. The results are compared with those obtained in the study of the Kirchhoff model. A mathematical software Maple was used for computational experiments.

By developing ocular prostheses, a number of problems arise, one of which is the design of the connection between the rigid optical part and the soft tissue of the corneaCornea ; their Young’s modules can differ by three orders of magnitude. In this case, the problem arises of creating some intermediate layerIntermediate layer , possibly with gradient properties, the purpose of which is to exclude injury to soft biological tissues. An analytical and finite element modeling of the interaction of a cylindrical optical prosthesisOptical prosthesis , an intermediateIntermediate heterogeneous layerLayer and the corneaCornea , in the framework of elastic media, in two versions: (i) without taking into account curvature (round platePlate ) and (ii) taking into account curvature (spherical domeDome or shell), was performed. In a simplified model, the intermediate layerIntermediate layer is represented as a spring layer, the determination of the rigidity of which will allow one to create an original design. Based on the proposed models, the stress-strain state of soft biological tissues was calculated.

In the present work, frictional contact interaction between the tip and the shaft of the tailTail transmissionTransmission ofTail transmission the MI-26 helicopter is considered in the framework of the linear theory of elasticity. The geometrical dimensions of the joint elements are taken from the design documentation. To set the profile of the tooth section, the necessary parametric equations were derived. To solve the tasks set, the finite element method and the ANSYSANSYS software were used. The main attention in the calculations was paid to the study of contact pressureContact pressure q and effective (equivalent) stressesEffective (equivalent) stresses σe on the tip teethTeeth surfaces that are in direct contact with the teethTeeth of the cup. In accordance with one of the proposed ways to increase the operational life of the node under study, a thin coatingThin coating with mechanical characteristics different from the teethTeeth original material was designed placed on the contacting surface of the tip tooth. The stress-strain state of the node has been calculated for various geometrical and mechanical parameters of the coatingCoating.

The Tymoshenko type modelModels of constructively anisotropic shell with auxetic properties is considered. Forced oscillationsOscillations in the frequency range including the first resonances are analyzed. The internal scattering of vibrational energy is taken into account. The influence of the transverse shearTransverse shear on the amplitude-frequency characteristics (AFCs) of the input malleability is investigated. It is compared with the frequency response obtained from the equations of the theory of Kirchhoff-Love.

The problem of connectedness of mechanical and thermal fields has acquired great practical importance in the mechanics of shells made of polymer compositePolymer composite materials. A number of specific properties of polymers, such as low thermal conductivity, high sensitivity to temperature change, large hysteresis losses, lead to harmonic loading under the effect of heat generation in the body of the shell, namely dissipative heating. To solve the problem of forced vibrations of polymer composite shells, taking into account thermomechanical connectivity, along with effective thermal-viscoelastic characteristics, it is necessary to specify effective thermal characteristics (thermal conductivity, thermal expansion, and specific heat). A complete system of relations is presented, including the equations of forced oscillationsForced oscillations of polymer-based composite shells of revolution, heat conduction equations taking into account the effect of heat generation, the constitutive equations of thermoviscoelasticity with the corresponding boundary conditions. As an example, we consider forced axisymmetric vibrations of a fibrous-layered cylindrical shell. In the following, it is assumed that the hard fitting condition is satisfied at the ends of the shell and the temperature is kept constant.

An approach to solving the problem of identifying the thicknessThickness of the layersLayers of a multilayer structureMultilayer structure using the combination of the finite elementFinite element methodMethod and artificial neural networksArtificial Neural Network (ANN) (ANNs) is presented. The simulation of a multilayer structure in the ANSYSANSYS finite element software is presented. The construction model consists of 4 layers, each of which has certain properties. The model is an imitation of the soil foundation of the road surface. SimulationSimulation in the form of a simplified, plane statement of the problem is considered. The analysis of surface wavesSurface waves, excited during the simulation of impact loadingImpact loading. The wave field of displacementsDisplacements in a given section of the structure is analyzed. Based on a numerical experiment, an approach is constructed to estimate the thickness of one of the layers of the structure. The application of ANN to restore information about the thickness of one of the layers is considered. As a result of the study, a method for identifying the thicknessThickness of the layersLayers of a multilayerMultilayer structureStructure was developed, based on a combination of the finite element method and ANN.

In this chapter, the classical molecular dynamics technique was used to investigate the atomistic structure of amorphous hafniumAmorphous hafnium oxide (HfO2) under pressure. The local atomic structure and the liquid-solid transition of HfO2 were analyzed the pair radical distribution functions, bond angle distributions, coordination number and the void distribution. The simulation reveals that although the fractions of structural units HfOx and OHfy strongly change with the density, the partial bond angle distributions of these structural units are identical for all constructed models. This result has enabled us to establish a relationship between the bond angle distributions and the fractions of structural units. From deformation of samples, elastic moduli and Poisson ratio were determined. The Young’s modulus and yield stress increase with the increasing density. The strain hardening becomes more pronounced as the density increases.

The digital image correlation (DIC)Digital Image Correlation (DIC) method is an advanced technical method to measure material strain by comparing several captured figures during deformation. DICDigital Image Correlation (DIC) provides full-field displacements and full-field strains in recorded images. In fact, there is much software using the DICDigital Image Correlation (DIC) algorithm. However, a commercial DICDigital Image Correlation (DIC) system requires a high initial investment. In this study, the DICDigital Image Correlation (DIC) algorithm was built based on the open-source of Matlab software, temporarily called NCORR DICDigital Image Correlation (DIC) . A DICDigital Image Correlation (DIC) system was built including a computer system, extensometer, tensile testingTensile testing machine, high-resolution camera, NCORR DICDigital Image Correlation (DIC) software and applied for AL5052AL5052 sheet metal test sample. After obtaining the images from the tensile testTensile test , the entire image will be included in the NCORR DICDigital Image Correlation (DIC) software for processing. To check the accuracy of the DICDigital Image Correlation (DIC) system, the results of the stress-strain curve of NCORR software were compared with the standard test method using extensometer. The obtained results measured from NCORR DICDigital Image Correlation (DIC) software were imported into a finite element method (FEM)Finite Element Method (FEM) software to check the accuracy of this method. Moreover, the hardening model (Voce, Swift, Kim-Tuan) provides empirical evidence and prerequisite conditions for the development of new fractureFractures criteria to describe behavior fracturesFractures .

We develop a physics based analytical model for AlGaN/GaNGaN high electron mobility transistorsHigh Electron Mobility Transistor (HEMT) (HEMT and MOS-HEMT) to study the I-V characteristics, current transfer characteristics, transconductance and drain-conductance. The model is modified from a model first presented by Chang and Fetterman for AlGaAs/GaAs HEMT (Chang and Fetterman in Solid-State Electron 30(5), 1987 [1], IEEE Trans Electron Dev Ed-34(I), 1987 [2]) The linear and non-linear drain currents have been separately calculated and merged them in order to evaluate the I-V characteristics. The threshold voltage has been evaluated from current transfer characteristics plot and verified from the transconductance parameter. We also consider the effect of polarization on threshold voltage of the devices. Moreover, to prove the exactness of our model, we compare our data with our experiment data for common HEMT, Hasan’s MOS-HEMT and Yoon’s HEMT with short channel.

Structural schemeStructural scheme of the electroelastic actuatorElectroelastic actuator for nanomechatronicsNanomechatronics and its transfer functions was obtained. Changes in the elastic complianceElastic compliance and stiffnessStiffness of the piezoactuatorPiezoactuator , accounting for the type of control, were found. The transfer functionsTransfer functions of the piezoactuatorPiezoactuator for nanomechatronicsNanomechatronics with transverse, longitudinal, and shear piezoeffects and voltage or current control were also obtained. Electroelastic actuatorElectroelastic actuator based on electroelasticity with piezoelectric or electrostriction effects is used for nanomechatronicsNanomechatronics . The structural schemeStructural scheme of the piezoactuatorPiezoactuator obtained in this work reflects the transformation of electrical energy into mechanical energy, in contrast to Cady’s and Mason’s electrical equivalent circuits of piezotransducer. The study explains the direct piezoeffect on the acting voltage of the piezoactuatorPiezoactuator . Changes in elastic compliance due to the direct piezoeffect determine the structural schemeStructural scheme of the piezoactuatorPiezoactuator with feedback for nanomechatronicsNanomechatronics systems. For the structural schemeStructural scheme , we considered the inverse piezoeffect, the elastic flexibility of the variables, the stiffness of piezoactuatorPiezoactuator , the direct piezoeffects, and the counter electromotive force, depending on the speed of the movement of the piezoactuatorPiezoactuator face. To construct the structural schemeStructural scheme of the piezoactuatorPiezoactuator , we solved the inverse piezoeffect equation and the wave equation under appropriate boundary conditions for calculating the parameters of the nanomechatronics system with piezoactuatorPiezoactuator . Due to the reaction of the piezoactuatorPiezoactuator and considering the direct piezoeffect, the elastic compliance and rigidity of the piezoactuatorPiezoactuator are changed. The structural schemeStructural scheme of the piezoactuatorPiezoactuator is obtained, considering the inverse piezoelectric effect and the back electromotive force due to the direct piezoelectric effect. The transfer functionsTransfer functions of the piezoactuatorsPiezoactuator for nanomechatronicsNanomechatronics with the transverse, longitudinal, shear, generalized piezoeffects and with both voltage and current controls are obtained.

In the recent years, researchers are trying to make devices self-powered. For this purpose, energy is converted from the ambient vibrations generated by the device or some other internal source. In this chapter, it is proposed to extract energy from the rotating objects to self-power small sensors. For this purpose, a stator and rotor of parallel plates are mounted on the coaxial shaft. The stator plate has a series of isolated piezoelectric patches of rectangular shape mounted on inner surface. The surface of the piezoelectric patches is covered by the magnetic slab of same size. The upper rotator plate is made of aluminum with inner surface having the series of magnetic slabs of same size and shape. Due to rotation of the rotating plate, periodic compressive magnetic force will be applied on the piezoelectric patches resulting in generation of electric charge. It is observed that output power of the order of 1.3572 W can be obtained from 11 mm radius plate harvester. The effects of rotating speed, piezoelectric patch dimension and magnet dimension on the generated root mean square electric power has been discussed in this paper.

In this paper, the work is dedicated to modeling and analysis of the distribution characteristics of stress-strain state and temperature in the vicinity of the contact region, analysis of the removal of metal during centrifugal-rotary processing (CRO)Centrifugal-Rotary Processing (CRO) detail in abrasive discrete environment. Examines the interplay of a single abrasive particleAbrasive particles with workpiece surfaceWorkpiece surface . The study is meant to explore the stress-strain state and temperature in the vicinity of the contact region, removal of metal from workpieceWorkpiece surface surfaceRemoval of metal from workpiece surface depending on the parameters of contact interaction (pressure force, processing time, sliding speed) which are associated with the process. The problem is addressed to the finite element methodFinite element method . Simultaneously with numerical modeling, experimentsExperiments were conducted on centrifugal-rotary setup and the dependence removal of metal on the processing technological parameters was investigated.

Compliant parallel mechanisms (CPMs)Compliant Parallel Mechanisms (CPMs) combining parallel mechanisms and compliant mechanismsCompliant mechanisms exhibiting many advantages such as high stiffness, high load carrying capacity, and high accuracy are widely used in various precision engineering applications. This chapter proposes a new design of a CPM using hollow flexural hinges combined with semicircular hinges and leaf springs for a non-resonant vibration assistedMilling millingVibration Assisted Milling (VAMilling) application. The mechanism will be actuated by piezoelectric actuators. The dimensions of the mechanism are optimized using an FEA-based global search evolutionary optimizationOptimization (NSGA-II)NSGA-II procedure, aiming to maximize the natural frequencies and decoupling between its two axes. The optimizationOptimization procedure is programmed in MATLAB whereas the ANSYS Mechanical ADPL code is embedded to support and enhance the calculation process. Using the optimal parameters, the established model for the mechanical performance evaluation of the CPM is verified with the finite-element methodFinite Element Method (FEM) . A prototype of the mechanism can be fabricated using wire EDM machining method and it will be incorporated into a CNC machining center to validate the performance of the established system.

Medical or healthcare devices assisting the rehabilitationRehabilitation of human joints often rely on functional mechanisms that could provide stable output torque. To achieve this target, available equipment usually uses motorized mechanisms combined with complicated sensorized control system. This paper presents a novel design concept of a monolithic compliant constant-torque mechanism (CTM)Constant-Torque Mechanism (CTM). It could produce an output torque that does not change in a prescribed input rotation. Thanks to the monolithic nature of the compliant mechanismCompliant mechanism, the device is more compact, lightweight and portable regardless of sensors or actuators. However, to be used in the rehabilitation equipment, the mechanism must produce a stable output torque in a sufficiently wide range of operation. The design methodology of this compliant CTM uses a genetic algorithmGenetic algorithm shape optimization. After obtaining the optimal configuration, finite element analysis is used to verify the design. This chapter also proposes a general design formulation to find the CTMs with a certain constant output torque in a specified input rotation range that can be used for human joint rehabilitativeRehabilitative devicesDevices or human mobility-assisting devices.

Loading capacityLoading capacity and stiffnessStiffness of spindle grinding machine are important features that determine the machining capability and precision of the machine. Characteristics of hydrostatic spindle bearing depend on geometric parametersGeometric parameter, oil properties, temperature and oil chamber pressure. The hydrostatic spindleHydrostatic spindle bearing with four high pressure chambers has been designed and manufactured for the 3K12 external circular grinding machine with bearing diameter and length corresponding to 70 mm and 56 mm, respectively. This chapter presents a simulation and experimental results to determine oil viscosity in accordance with the actual geometry bearing parameters in order to achieve the highest loading capacity and stiffness of the bearing. This is the base for determining the characteristics of lubricant oil under the specific machining process and working conditions of the hydrostatic spindle bearing.

This paper presents an inverse methodInverse method to estimate the convection coefficientConvection coefficient in the gap of rig test for bearingRig test for bearing by using two measured temperatures. The measurement temperatures are obtained by performing the test for different speeds. The temperature is then used as input data in the inverse algorithm. The method is constructed based on finite different thermal modelFinite different thermal model and an optimization method—the conjugate gradient method. After acquiring the convection coefficients for various speeds, formulae of the convection coefficient of two bearing kinds are established. To validate the inverse results, a comparison of simulation and experimental temperatures has been carried out. The results show that the predicted temperatures are in good agreement with the measured temperatures.

We propose a combination of algorithms called the Kalman particle filter (KPF)Kalman Particle Filter (KPF) that overcomes the object tracking occlusion problemOcclusion problem in image processing while also achieving a reasonable computation time. When object occlusion occurs while using a Kalman filter (KF)Kalman Filter (KF), we switch to the particle filter (PF)Particle Filter (PF) to track the object until the system is stable, and then switch back to the KF. We compared the results of running each algorithm (KF, PF, and KPF), independently, executed 30 times; the tracking performance was evaluated using six different methods. We found that KPF successfully addressed the occlusion problem, providing accurate estimates using highly efficient operations.

This paper considers a simplified version of a deep generative convolutional neural network. The model is designed to generate images containing various forms of defects. Defects are presented as a simplified basic geometric primitive. At the network input, parameters are described that initiate the class of the figure and its geometric characteristics. The proposed model is designed to conduct research on the quality of image generation, the possibility of combining various types of defects, studying the influence of various parameters of the training set. Based on these studies, it is possible to build a more advanced generative model capable of restoring the shape of internal defectsInternal defects in structural elements based on ultrasonic non-destructive testing methods.

This paper proposes a 2 × 2 direct mapping (DM)2 × 2 Direct Mapping (DM) based of an underwater acoustic transmission (UAT) scheme for data signals based on filter bank multicarrier (FBMC)-low density parity check (LDPC)Filter Bank Multicarrier (FBMC)-Low Density Parity Check (LDPC) . The 2 × 2 DM2 × 2 Direct Mapping (DM) multiple-input multiple-output (MIMO) transmission mechanism, FBMC modulation, LDPC channel coding, adaptive binary phase shift keying (BPSK) modulation and four offset quadrature amplitude modulation (4-OQAM), and power assignment mechanism are integrated. The performances of bit error rates (BERs) and data error rates (DERs)Data Error Rates (DERs) of the proposed underwater data transmission schemeUnderwater data transmission scheme with perfect channel estimation (PCE) (0%), and the channel estimation errors(CEEs) of 5%, 10%, and 20% are investigated. The bit error rates (BERs) of data signals for underwater transmission must be less than 10–5. The transmission power weightings and ratios of power saving (PS) for the proposed underwater acoustic transmission system are explored through simulations. From these simulation results, we evaluate the performances of the proposed advanced data UAT scheme.

The root canal treatmentRoot canal treatment is the popular method for disinfection of infected teeth. Root canal treatmentRoot canal treatment involves cavity preparation (root canal shaping), filling and sealing. The endodontic handpiece with endodontic files are used for the shaping of the root canals. In this process, the endodontic files dislodge material from the internal wall of the root canal. Material dislodging causes root canal shaping forces and vibrationVibration. Excessive forces and vibrationVibration may increase the chances of iatrogenic error like the instrument separation, root tooth fracture and root perforation. These errors can be predicted and eliminated by assessment of the vibrationVibration signals of endodontic handpieceEndodontic handpiece. Endodontic handpieceEndodontic handpiece composed of several parts like motor, transmission system and endodontic files and generate vibrationVibrations at different frequencies. The accelerometer is used for the vibrationVibration signal acquisition of the handpiece. The vibrationVibration signal quality is associated with the position of the accelerometer on the endodontic handpieceEndodontic handpiece. This study is determining the suitable position of the accelerometer endodontic handpiecesEndodontic handpiece, for the better signal acquisition. The entire handpiece is divided into the segments of equal length. Then eight signals for each segment are recorded. For each position of the accelerometer, the root mean square of signals is compared, in order to accrue signals of higher amplitude. In this study, it has been found out that the amplitude of vibrationVibration is significantly varied along the length of the handpiece. On the base of this study, a suitable location for the accelerometer has been found out.