Physics and Mechanics of New Materials and Their Applications

One of the key components of low-temperature fuel cells with a proton-exchange membrane is an electrocatalyst contained in the porous electrodes. The most widespread synthesis methods are the liquid-phase ones that allow controlling the microstructure of the catalyst and, thus, its functional parameters. We have investigated the influence of various conditions of the liquid-phase synthesis on the morphological and electrochemical characteristics of the resulting platinum–carbon catalysts. An increase in the synthesis temperature has been established to allow for the narrowing of the size dispersion and the decrease in the average size of platinum nanoparticles. It has been found that the presence of a carbon support during the synthesis makes it possible to enhance the uniformity of the Pt NPs’ distribution over the surface of the support and decreasing the average particle size. As a result, the values of the active surface area grow almost 1.2–2 times compared to the homogeneous synthesis, during which the resulting colloid of platinum particles is deposited on the carbon support after the reduction. When using the molar ratio of hydroxyl groups/platinum in the range from 5 to 20 during the synthesis, the resulting Pt/C catalysts are characterized by an active surface area of more than 85 m2·g−1Pt. The possibility of scaling the synthesis method to obtain at least 1 g of the catalyst, which is not inferior in functional parameters to its commercial analog both before stress testing and after its completion, is also shown.

A comparative analysis of different methods for the bimetallic PtCo/C fuel cells electrocatalysts synthesis was carried out. The structure and catalytic activity of materials obtained by borohydride synthesis method, synthesis on a cobalt-containing carbon substrate, polyol synthesis method and modified polyol synthesis method were studied using a complex of modern methods. Some of the obtained PtCo/C materials turned out to be comparable in activity to commercial analogues. Based on the results of a synthesis methods, comparative analysis used, the synthesis method using a composite cobalt-containing carbon support can be recommended as the most promising for further optimization.

Production of highly efficient platinum-containing catalysts for PEMFC cathode is an urgent task for the development of hydrogen energy. Fifteen bimetallic catalysts for the ORR were synthesized by various modified borohydride synthesis methods using de-alloying treatment. Of these, 33.3% PtNi/C and 33.3% PtCu/C materials were subjected to acid treatment, 13.3% PtNi/C and 20% PtCu/C were subjected to electrochemical leaching. A comprehensive assessment of the composition and structure of the catalysts was carried out using TEM, STEM, XRD, TXRF, and EDX methods. The electrochemical behavior of the materials was estimated by cyclic and linear voltammetry. The resulting bimetallic catalysts exceed the commercial Pt/C analogue in the ORR mass activity by 1.2–4.3 times. Most of the studied PtM/C catalysts (66.6%) exceed the DOE target 2025 (440 A/gPt). According to the results of the study, PtCu/C catalysts, subjected to electrochemical de-alloying, are considered promising for use in PEMFC MEA.

Thermally expanded graphite (TEG) is a vermicular-structured carbon material that can be prepared by heating expandable graphite compounds. Liquid phase exfoliation of TEG obtained from graphite nitrate cointercalation compounds (GNCCs) with organic substances allows obtaining dispersions of carbon nanoparticles, namely few-layer graphenes as well as small graphene structural fragments. This paper presents the results of complex investigations of structural features of triple GNCCs with acetic acid, formic acid, ethyl acetate and acetonitrile as well as TEGs on their base. X-Ray powder diffraction and scanning electron microscopy were used for studied GNCCs and TEGs characterization. GNCCs were used as a source for thermally expanded graphite which can be considered as perspective precursor for graphene and related structures. Morphology of the carbon nanoparticles formed from corresponded TEGs by liquid phase exfoliation in tert-butanol assisted with sonication is discussed. The most promising results were observed for the TEG sample obtained from a triple GNCC with acetic acid and acetonitrile.

Sn-doped TiO2, F-doped TiO2 and Sn-F co-doped TiO2 materials (5.0 at.% Sn, 5.0 at.% F) were synthesized by sol-gel method and calcined at different temperatures. All of obtained materials are nanoscale, particles size is 12–40 nm, which depends on composition and calcination temperature. High photocatalytic activity is characteristic for all materials both under UV and visible light irradiation. Sn-F co-doped TiO2 nanomaterials are characterized by higher photocatalytic activity, than Sn- or F-doped TiO2.

A metalens operating at 4 µm is numerically designed. By adjusting the diameters of the pillar array from 500 to 1000 nm, the metalens achieves 2π-phase modulation with over 75% transmission efficiency. Further analysis indicates that the designed metalens achieves expected axial dispersion, but the transmission efficiency shows strong dependency on the incident angle. Then fabrication aspects are shown. Firstly, conditions of silicon-on-silicon oxide structure fabrication are studied in terms of plasma deposition and annealing temperature and their effect on the physical and mechanical (roughness, grain size, stress) and optical properties (refractive index) of the layers. Both should be adjusted to provide enhanced features of metalens. In particular, refractive index could be tuned in range from 1.45 to 1.9 and from 3.71 to 5.15 for silicon oxide and silicon layer, respectively. Finally, experimental dependences of microstructure formation on the silicon surface by plasma chemical etching technique in a combined discharge of fluoride plasma are presented. Thus, structures with a height of 246 nm and a relatively low roughness of 0.63 nm were obtained.

The barium strontium niobate Sr0.6Ba0.4Nb2O6 thin film was grown by the RF cathode sputtering technique in an oxygen atmosphere on a p-type Si(001) semiconductor substrate. According to X-ray diffraction studies, it was established that the barium-strontium niobate film was c-oriented textured, and there were practically no unit cell strains in them. The film surface has a uniform granular relief, does not contain cavities or cracks, and the root-mean-square roughness in a typical area is ~ 17.6 nm. It has been found that polarization in the SBN-60 film has predominantly an out-of-plane direction and the film was spontaneously polarized after synthesis. It is shown that the value of the relative dielectric constant, calculated from the C(U) dependence of the heterostructure, measured at a fixed temperature, is 500–832 in (−190… + 200)°C temperature range, and at low temperatures dielectric constant exceeds those for the corresponding single crystal. The reasons for the identified regularities and features of the manifestation of memory effects are discussed.

Using conventional ceramic technology, solid solutions (SS) of the system (1 – x)(Na0.5K0.5)NbO3 – xBiFeO3 with x = 0.05, 0.20, 0.55, 0.95 were obtained by solid phase synthesis in two stages. It has been established that the structure of the studied solid solutions critically depends on technological regulations: solid solutions close in composition to (Na0.5K0.5)NbO3 are characterized by the highest sintering temperatures, low relative densities and their discrepancy in trial and experimental samples at one and the same temperature; and those close in composition to BiFeO3 are characterized by low sintering temperatures, high relative densities and practically identical relative densities of trial and experimental samples. Two phase transitions have been identified: (i) in fact the decomposition of SS, takes place in the interval 0.00 < x < 0.05, (ii) transition from the C-phase to the Rh-phase occurs in the interval 0.55 < x < 0.95.

In the present paper, a series of TiN coatings, deposited using magnetron sputtering unit were characterized in terms of their stoichiometry, microgeometry, and microstructure. The coatings were obtained at 1, 3, 5, 7 sccm N2 flow at constant chamber pressure. Their thickness and microstructure were studied using scanning electron microscopy and the stoichiometry was observed using energy dispersive X-ray analysis. The microgeometry of the coatings was obtained using atomic-force microscope. Stable modes of obtaining TiN coatings with nitrogen content from 8.56 to 46.04 atomic percent with an average deposition rate from 6.8 to 8.86 angstroms per second were demonstrated. The results demonstrated an almost linear relationship between the composition of the coatings and the composition of the gas mixture during the deposition process up to a nitrogen flow of 5 sccm. At higher values of the nitrogen flow, the composition of the coatings does not change significantly. This observation can be used to predict the required composition of the gas mixture under the given process parameters to obtain TiN coatings of the required thickness and with the required elemental composition.

In this paper, a semiconductor ferroelectric antimony sulfoiodide with photocatalytic activity was obtained using an optimized hydrothermal method. The influence of the precursors, time and temperature of hydrothermal treatment was studied. As a result, phases differing in purity, length and shape of particles were obtained. The sample, aged for 2 h, contained a significant number of impurities in the form of antimony sulfide. Samples, aged for 4 and 5 h, had noticeably fewer impurities. The phases, obtained after 6, 10 and 24-h exposure, had a sufficiently large yield and well-formed long rods. The results of X-ray phase analysis showed the presence of the target phase in all cases, while the longer the synthesis time, the better the crystallization of the SbSI rods. The results of scanning electron microscopy showed that the particles have the shape of a rod, which consists of smaller needles, and with increasing synthesis time their length increases. The needles thickness varies from one to several tens of microns. The study of photocatalytic properties has shown that the rods exhibit mild photocatalytic activity, compared to powder materials, which is consistent with theoretical concepts.

The pulsed energy impacts are promising methods for the pretreatment of refractory mineral raw materials (refractory ores and concentration products) to increase the disintegration, softening, and liberation performance of finely disseminated mineral complexes, as well as to increase the contrast of surface properties for minerals with similar physicochemical and technological properties. In this work, we used analytical electron microscopy, electrode potential testing, sorption and flotation measurements to study changes in the surface morphology, electrochemical, physicochemical, and flotation properties of the natural pyrrhotite, pentlandite and chalcopyrite exposed to non-thermal action of the repetitive high-power nanosecond electromagnetic pulses (HPEMP) and low-temperature plasma of dielectric barrier discharge (DBD) in air at atmospheric pressure. For monomineral flotation of pyrrhotite and pentlandite, we established the optimal mode of preliminary electromagnetic impulse treatment of minerals (ttreat. = 10 s), at which the contrast of their flotation properties increases in the mean on ~20%. Short-term (10 s) treatment of pyrrhotite by DBD caused the shift of its electrode potential to the region of negative values occurred, which causes the effect of a decrease in the pyrrhotite sorption and flotation activity. In the result of short-term (10 s) HPEMP pretreatment of chalcopyrite, the increased floatability of sulfide mineral from 75% up to 92% due to a greater amount of a collector, accumulated at sulfide surface, and its higher electrode potential established. Thus, the advantages of using the short-term (ttreat. = 10−30 s) impulse energy impacts for improvement of the structural, physicochemical and technological properties of iron, copper, and nickel sulfides are shown.

This study focuses on the advancement of new techniques for cryopreservation of reproductive cells at low temperatures, including sturgeon fish. The approach is based on smart freezing process control. To ensure cryoprotectant and reproductive cells are not damaged prior to vitrification, a piezoactuator is used to stir the mixture. This technique facilitates the intensive mixing of cryoprotectant, promoting the diffusion of the substance through the cell membrane. During direct vitrification, researchers observe a phase transition phenomenon in the presence of crystal formation. This study constructs a mathematical model to investigate this process while comparing numerical experiments to in situ experiments. The results obtained have implications for selecting optimal parameters required for the low-temperature preservation of fish reproductive cells.

Hybrid surface plasmon polariton waveguides (HSPPWGs) are used to transmit and manipulate nanoscale optical signals as plasmonic waveguides. This increases optical communication network bandwidth and data transmission rates. Due to their unique properties, HSPPWGs are versatile photonics and integrated optics platforms. In order to achieve better results, the study used several proposed structures and simulated them using the COMSOL Multiphysics software with MATLAB. The gain in the quantum dots significantly improved the results with a choice of certain semiconductor active material. The aim is to reach more than ten times the original length (without material gain) and have good quantum confinement according to the FoM test and Γ-confinement factor, which causes a jump in the calculated propagation length of the hybrid waveguide. Three cases result for propagation lengths in the first case High QDisk 2 nm indicates a maximum Lp value of 37 μm at λ = 1550 nm and 30 μm at λ = 1300 nm. The second case involves increased propagation length in the 1300 – 1600 nm wavelength range, with Lp = 55 μm at λ = 1550 nm and Lp = 48 μm at λ = 1300 nm. In the third case, using AlGaAs 3.0238 in QD 3 nm height, confinement was 0.345, 0.370 for Γ-confinement and 85.110 for FoM, while Lp was 68 µm and 70 µm for wavelengths of 1300 nm and 1550 nm.

The model of deformable and polarizable atoms presents ab initio calculations of the specific heat capacity of Ne and Ar crystals under and without pressure. The short-range potential takes into account both the three-body interaction and the deformation of the electron shells of dipole-type atoms in the pair and three- body approximations. The specific heat capacity was studied in a large temperature and pressure range using a dynamic matrix, based on an ab initio short-range repulsive potential and integration over ten main value points of the Chadi – Cohen method. The values of the specific heat capacity of crystalline Ne and Ar increase both under pressure and without it, if we consider the contributions of three-body forces, associated with both the overlap of the electron shells of atoms and the deformation of the electron shells. The comparison of our calculations with those of other authors and experimental data is satisfactory.

Novel piezo-active 2–1–2 composites with two single-crystal components are studied to show their large hydrostatic parameters and figures of merit concerned with the hydrostatic, longitudinal, and transverse piezoelectric effects. The 2–1–2 composite contains layers of domain-engineered [0 1 1]-poled relaxor-ferroelectric (1 – x)Pb(Zn1/3Nb2/3)O3 – xPbTiO3 single crystal (x = 0.0475–0.09) and layers that contain aligned piezoelectric Li2B4O7 single crystal rods in polyethylene, and these layers are distributed regularly and in the form of an elliptic cylinder. Due to the microgeometry of the composite and the piezoelectric properties of the single-crystal components, large values of the hydrostatic figure of merit $$d_{h}^{*} g_{h}^{*} > 2 \cdot 10^{ - 10} \;{\text{Pa}}^{ - 1}$$ d h ∗ g h ∗ > 2 · 10 - 10 Pa - 1 and longitudinal figure of merit $$d_{33}^{*} g_{33}^{*} \sim 10^{ - 10} \;{\text{Pa}}^{ - 1}$$ d 33 ∗ g 33 ∗ ∼ 10 - 10 Pa - 1 are achieved in specific volume-fraction and aspect-ratio range, at relatively small volume fractions of the single-crystal rods. An effect of the aspect ratio of the rod base on the piezoelectric performance and figures of merit if the composite is discussed. Large figures of merit of the studied composites can promote hydroacoustic and piezoelectric energy-harvesting applications of the studied 2–1–2 composites.

A modification of the well-known laminar composite structure with 2–2 connectivity leads to changes of the effective physical properties and their dependences on the composite content and microgeometric characteristics. The present chapter reports new results on novel three-component 2–1–2 composites with a high piezoelectric sensitivity and large hydrostatic parameters. In the 2–1–2 composite, there are parallel-connected layers of two types. The first type represents a ferroelectric domain-engineered [0 0 1]-poled lead-free single crystal based on solid solutions of alkali niobates-tantalates with the perovskite-type structure. In the second type of the layers, ferroelectric ceramic rods in the form of an elliptic cylinder are regularly aligned in a large polymer matrix, and the ceramic component is chosen among the perovskite-type compositions being either leaf-free or lead-containing. The hydrostatic piezoelectric coefficients dh* and gh*, related figure of merit dh*gh*, and their non-monotonic behaviour are studied by taking an orientation effect into account. This orientation effect is caused by rotations of the ceramic rod bases in the polymer medium. The aforementioned hydrostatic parameters are compared to those of the conventional two-component ceramic-polymer composites, and some advantages of the studied lead-free 2–1–2 composites are discussed. These novel composites are suitable for hydroacoustic applications.

Artificial periodic composite structures have great potential for the development of transducers, sensors, as well as smart systems and structures for active noise reduction, transducer design, energy harvesting, etc. In this paper, elastic metamaterials with multiple arrays of strip-like voids are proposed for providing wide band gaps, in which elastic waves cannot propagate. The goals of the present study are the manufacturing of these elastic metamaterials and the experimental investigation of wave propagation in such periodic structures. Several samples of elastic metamaterials have been manufactured on a dual extruder 3D printer since the dissimilar components do not demand additional bonding and have been fused by a heated extruder during printing. A laser Doppler vibrometer has been used to detect the wave motion, excited by a rectangular piezoelectric transducer. Wide band-gaps were observed in the measured transmission coefficient for the manufactured specimen.

The features of the temperature evolution of piezoresonance spectra, as well as the temperature dependences of the pyroelectric and dielectric properties of the PbZr1-xTixO3 system ferroelectric ceramic samples for 0.02 ≤ x ≤ 0.05 before and after thermostatting at T = 450 ℃ were studied. It has been established that after exposure to elevated temperature for more than 1 h, in all samples, upon cooling, an irreversible increase in the temperature of the phase transition from the ferroelectric to the antiferroelectric state is observed. Subsequent polarization with cooling through the Curie temperature does not restore the initial position of the phase transition point on the temperature scale in the samples. An assumption has been made about the connection between the observed phenomena and the ordering of clusters with a PbTiO3 type structure, existing in the form of interlayers of elements of binary oxides ZrO2 and TiO2, coherently embedded in the crystalline matrix phase.

Using the method of two-stage solid-phase synthesis, involving mechanical activation of the synthesized powders and subsequent sintering using conventional ceramic technology, ferroelectric multicomponent solid solutions, based on the PZT system, were produced, characterized by fairly high Curie temperatures and pyroelectric coefficients, high coefficients of pyroelectric sensitivity and resistance to vibration interference, which makes it possible to classify them as pyroelectric materials, are promising for use as working elements of sensors for pyroelectric receivers of radiant (thermal) energy.

This article presents the results of studying the samples, obtained on the base of lead magnoniobate (PMN) and described by the general formula (1 – x)PbMg1/3Nb2/3O3 – xPbMg1/2Nb1/2O2.75, where the value of parameter x varies from 0 to 1 with a step of 0.1. Experimentally, it was shown that all compounds from this series are ferroelectric-relaxors. With an increase in the value of the parameter x, the proportion of nonstoichiometric PMN with an artificially set oxygen deficiency increased. Measurements of the dielectric constant of the synthesized samples and the tangent of the dielectric loss angle showed violation of the Curie-Weiss law, which indicates the diffusion of the phase transition.

In present work, particular aspects of the large-signal switching properties and electromechanical hysteresis of the PZT-type porous piezoceramics were investigated by comparison with the dense piezoceramics of the same composition. Large-signal ferroelectric polarization and strain hysteresis loops were recorded at the bipolar electric fields in the range of 0–5 kV/mm and in the frequency range of 0.01–5 Hz. Measurements and analysis were performed by means of the Electromechanical Measurement System (STEPHV) and Electromechanical Response Characterization Program (STEP), combining large signal modelling of the mechanical and electrical behavior of ferroelectric materials.

In this work, the microstructure features and complex electromechanical parameters of porous piezoelectric ceramics based on the PZT system with different relative porosities and pore sizes are studied. Complex elastic, dielectric, and electromechanical parameters of porous piezoceramics were measured on the thickness mode of vibration of standard samples and analyzed using the piezoresonance analysis program (PRAP). It was shown that the microstructural features of porous piezoceramics determine the character of the porosity dependences of real and imaginary parts of dielectric, piezoelectric and electromechanical properties of porous piezoelectric ceramics.

In this work, the ceramics of (1 – x)Na0.5K0.5NbO3 – xNa0.5Bi0.5TiO3 were prepared by conventional solid state method. At room temperature in studied system, two morphotropic phase transitions occur near the extreme components of the system: (i) from tetragonal to pseudocubic at 0.1 < x < 0.2 and (ii) from pseudocubic to rhombohedral at x > 0.9. The best storage properties are observed near these transitions: Weff = 0.6 J/cm3 and η = 63%, at x = 0.2; Weff = 0.1 J/cm3 and η = 75% at x = 0.9 for E = 25 kV/cm and E = 27 kV/cm, respectively. Therefore, the ceramic with 0.1 < x < 0.2 and 1.0 < x ≤ 0.9 is promising candidate lead-free materials for energy storage devices.

Ferroelectric and dielectric characteristics of multiferroics solid solutions ceramics of the (1 – x)BiFeO3 − xPbFe0.5Nb0.5O3 composition with x = 0.3, modified superstoichiometrically with GeO2 in amounts (0.5–1.0) wt.%, were studied. It is noted that the temperature dependencies of the real part of the complex dielectric permittivity and the dielectric loss tangent exhibit anomalies in the vicinity of the ferroelectric phase transition, while the nature of their changes in the vicinity of the latter allows us to classify the studied objects as ferroelectrics with a diffuse phase transition. The ferroelectric properties of the modified objects at room temperature indicate that it was not possible to obtain saturated dielectric hysteresis loops for all samples in the analyzed field range. This is apparently due to high coercive fields indicating improved electrical strength of ceramics. In this regard, it is advisable to use materials, based on 0.7BiFeO3 − 0.3PbFe0.5Nb0.5O3 solid solutions, developed during the research, to create and study new multifunctional media with special electrophysical parameters, promising for applications in innovative areas of electronics.

Materials, based on strontium titanate, have many applications in microwave technology. The main methods for achieving target characteristics when developing such materials are modification of the composition and creation of low-dimensional structures. Due to the high cost of single crystals of suitable shape for measuring electrical parameters using standard methods, ceramics and composites are being considered as an alternative. The work proposes to use a set of simpler measurement techniques that allow for a primary analysis of the microwave response of single-crystal materials and simplify further modeling and calculations. The results of calculating the resonance response of a model single-crystal sample of strontium titanate are presented. The influence of the features of measurement techniques on the final results is analyzed. Conclusions are drawn about the feasibility of conducting comprehensive studies using various techniques. The results obtained will help in further calculations and modeling of the electrical parameters of single-crystal samples of functional materials.

A new layered perovskite-like oxide Bi7Sr2TiNb5O27 was synthesized by the method of high-temperature solid-state reaction, in which partial substitution of bismuth (Sr2+) atoms in the dodecahedra of the perovskite layer (A-positions) by Bi3+ ion took place. X-ray structural studies have shown that compound was single-phase and had the structure of Aurivillius-Smolensky phases (ASPs) with close parameters of orthorhombic unit cell, corresponding to space group A21am. The dependence of the relative permittivity ε/ε0, the tangent of loss tan σ at different frequencies on temperature and piezoelectric constant d33 were measured.

The protective effect of an organic compound of imidazole class on the corrosion of mild steel in sulfuric acid was studied. Modification of the organic base with bromine anions increases the protection effect. The blocking-activation mechanism of the protective effect of benzimidazole hydrobromide was determined by gravimetry, impedancesometry and polarization measurements. The interaction of adsorbed particles in the adsorption layer was found to be increased with increasing organic salt concentration. The features of the cellular microstructure of the films have been studied by scanning electron microscopy. AFM imaging study showed that the Fe coatings have a globular character and depend on the type of inhibitor and its concentration. It has been established that the most reliably protect Fe from corrosion are the coatings representing aggregates of large, accreted globules with maximum electrical conductivity.

Experimental data on the dielectric spectra of the organic films were studied and analyzed. An equivalent circuit consisting of two series-parallel RC- circuits is used for computer modeling and interpretation of experimental data of films with negative electrical capacitance in the high-frequency range. The critical frequency of changing the sign of the electrical capacitance has been determined. The negative electrical capacitance of the films under study is due to two factors: high-frequency processes of strong relaxation polarization with inverse electric field strength and low-frequency processes of hopping-type conductivity.

The broadband optical limiting of single-walled carbon nanotubes (SWCNTs) with tetracarboxy-substituted phthalocyanine ligand composite was assessed. For this purpose, optical studies of the spectra and nonlinear response were carried out. The value of the normalized transmittance in experiments on optical limiting, provided with the method of a fixed absorber arrangement, has been evaluated. The description of the nonlinear change in the transmitted energy fluence was carried out using the radiative transfer equation (RTE) for the case of a threshold dependence of the absorption coefficient on intensity. The determination of the nonlinear absorption coefficient and the threshold total pulse energy was performed on the optical limiting measurement data for a pulse. Knowing these parameters, the attenuation of the pulse was simulated by two methods: Z-scan with an open aperture and when the absorber was immovable at the focus of the lens.

This study compares the equivalent properties of a PZT-Ni composite to those of a standard PZT-Air porous piezocomposite. The effective properties of both composites were estimated principally numerically using the finite element method and the Hill-Mendel principle, with fully homogeneous and highly inhomogeneous polarized piezoceramic matrix models. The numerical findings concerning the fully polarized model were verified analytically using Mori-Tanaka homogenization technique. The elastic moduli of PZT-Ni and PZT-Air composites and the dielectric permittivity of PZT-Air composite exhibited no significant dependence on polarization inhomogeneity; however, the piezoelectric coefficients showed a considerable dependence on the chosen polarizations model. The incorporation of metal inclusions into the piezoceramic matrix increases the polarization field at the interface, which improves the composite’s homogenized dielectric permittivity moduli. The PZT-Ni composite’s improved dielectric permittivity boosts its efficiency in lighting electronics, voltage controllers, and multilayer small-volume high-performance capacitors.

In this research, a finite element model of regular highly porous foam structure based on the macro or nano sized Gibson-Ashby cell is proposed. To account for the dimensional effect, the Gurtin-Murdoch model was used, which considers the surface stresses arising on the boundaries of the cell. The computer model construction, finite element meshing, and the numerical solution of the homogenization problem were carried out in the ANSYS software package. Here, the influence of the cell geometry at a fixed porosity was initially investigated. The obtained results confirm that the effective moduli of highly porous structures composed of Gibson-Ashby cells depend not only on porosity, but also on the geometric configuration. For example, at the same porosity, cells with thicker edges have greater rigidity. Numerical experiments were also carried out at the nanoscale, that is, model considered surface stresses. The relative stiffness moduli of nanoscale structures are significantly higher than similar values of regular size structures. Moreover, the dimensional effect has a greater influence on the effective properties of a highly porous material than the cell configuration. For example, the relative effective Young’s modulus of a regular size structure with thick edges is smaller than that of a nanoscale structure with thin edges. In this paper, cells with a complex geometric structure are considered, so a representative volume loses the isotropic properties of the material. Therefore, a study of the anisotropic effective properties based on the Zener coefficient was also carried out.

Cowin and Nunziato developed the theory of microdilatation, which allows one to effectively investigate various problems for poroelastic bodies, containing unfilled pores, based on analytical approaches. The theory of microdilatation is based on a system of differential equations, which contains several parameters, the values of which are not available in reference books, which limits the use of this theory in practice. Some publications propose schemes for determining these parameters. This paper proposes a method for determining such important parameters of the theory of microdilatation as stress parameter with porosity change and void stiffness coefficient. To determine the values of these parameters, a scheme has been developed based on a comparison of solutions plane contact problems for an elastic body in the form of a strip, the deformation of which is described by the Cowin-Nunziato theory of microdilatation, and for the corresponding elastic body in the form of a rectangle containing real, unfilled, uniformly distributed voids in the shape of circles. The first problem was studied, based on a numerical-analytical method for solving the resulting integral equation, the second problem was studied by using the finite element method. Control of the correctness of the obtained parameter values was carried out by comparing the results of studying similar contact problems with other values of the geometric parameters of the strip and rectangle.

Nanocrystalline copper is one of the best suited materials for integrated chips industries due to its high mechanical stability and less resistivity. In the present work, the molecular dynamic simulation approach is employed to analyze the mechanical properties and potential energy of single crystal nano copper. The response of temperature as well as strain rate on selective properties has been explored. Nanocrystalline copper deformation under virtual uniaxial tensile test has demonstrated that the increase in strain rate from 1.0 × 108/s to 5.0 × 1010/s provides a significant change in mechanical properties of nano copper. In addition, the outcomes reveal that the mechanical properties of crystalline nano copper degraded with temperature response under uniaxial tensile loading. With increasing temperature from 50 to 500 K, potential energy response shows an increase in instability of structure at higher temperatures. The results may help to accelerate functional applications of nanocrystalline copper at high temperatures subjected to a different levels of strain rates.

In this paper, we considered the plane problem of steady-state bending vibrations of a hinged-supported bimorph in an alternating magnetic field, considering damping. The bimorph under study consisted of a multilayer electromagnetoelastic composite modeled using the effective modulus approach. Within the framework of Kirchhoff's hypotheses, an applied theory was constructed, which considered the quadratic distributions of electric and magnetic potentials along the thickness of the bimorph and considered heterogeneity in the longitudinal direction. In addition, the theory introduced linear viscoelasticity. Using the resulting theory, distributions of electric, magnetic, and mechanical fields were constructed. Comparison of the obtained results, based on the theory, with the results of the finite element model in the COMSOL Multiphysics package showed a good convergence of the results. Next, based on the obtained theory, the behavior of plate de-flection in the vicinity of the first resonance was studied at various values of the damping coefficient, which showed that the obtained theory can be used to analyze the bandwidth of converters, based on constructing the amplitude-frequency characteristics of bimorphs made of an electromagnetoelastic composite.

Within the framework of the geometric theory of diffraction, based on an explicit analytical expression, the amplitude of displacements in the back-reflected high-frequency longitudinal wave from the surfaces of cavity defects and non-planar cracks in elastic bodies was studied. A detailed numerical analysis of the amplitude of displacements in the case of back-reflection from a cylinder, sphere, triaxial ellipsoid, one-cavity and two-cavity hyperboloids, elliptical and hyperbolic paraboloids for various values of geometric parameters of boundary surfaces was carried out. Graphs of the dependence of the amplitude of displacements on the distance of the source and receiver of the wave from the defect surfaces are constructed. The focal points of the amplitude of displacements in the reflected wave from each type of defects have been established.

In this paper, we present the results related to the development of a technique for low-frequency acoustic non-destructive testing of layered composite structures. The main goal was to detect and pinpoint potential bundles in such structures. To do this, we used as an object of research a manufactured carbon fiber panel consisting of eight layers, with the addition of inclusions between the fourth and fifth layers. By performing a finite element analysis of the effects of an omnidirectional piezoelectric transducer mounted in the center of the panel, we found that the amplitudes of the out-of-plane velocities increase significantly near the lamination regions. Our technique includes the use of a laser vibrometer and a simple method of velocity analysis that allows us to detect and accurately locate lenticular delaminations within the geometry under study. It was found that the results of the simulation were sufficiently like to the experiment. In addition, we also considered a model case, where the defect is located between the first and second layers of the panel. It is noted that the behavior of the velocity field in this case differs from the previous variant, but the average amplitude of the out-of-plane velocity undergoes a slight decrease relative to the case of the defect occurring in the center of the thickness.

The modal analysis problem for a beam performing bending vibrations is considered. The defect in the beam is modeled as a change in the cross-section area and the moment of inertia. The damage identification is based on the recovery of these coefficients by using additional information about resonant frequencies and eigenmodes. The solution of such a coefficient problem is conducted to minimize a special misfit functional. The paper presents the construction of this functional, considering the specificity of the modal analysis problem. The trust region method was used to solve the optimization problem. The gradient and the Hessian of the misfit functional were obtained on the sensitivity analysis of the forward problem.

The stress state of a three-layer spherical shell was calculated on the basis of exact, asymptotic solutions and solutions according to some applied theories. As applied theories, we took theories, based on the theory of a single normal for the entire package on the theory of a broken element, and on the theory that considers transverse shear. A comparative analysis of the stresses, obtained from all five solutions, is given. The asymptotic solution, constructed in the work, based on three-dimensional equations, indicates methods for constructing refined applied theories for inhomogeneous thicknesses, including layered plates and shells.

The article describes matrix representations of the displacements, stresses, and deformations in layered isotropic and transversely isotropic structures for the case of elastic wave sources, located inside a layer package. The calculated relationships are based on the generalized method of scalarization of dynamic elastic fields, developed by V.P. Sizov [1] and implemented in original software. The noted results were used to simulate the process of diagnosing the state of plane-layered structures made of isotropic and transversally isotropic materials using the acoustic active method of non-destructive testing.

The work solves the problem of multi-parameter optimization of vacuum ion-plasma coatings based on the use of a database, which was formed by the authors over several years of experimental and applied work in the field of increasing the antifriction properties of engineering products. Three types of monolayer vacuum ion-plasma coatings (thin films) with a thickness of 0.5–3.5 μm were considered as the object of study: coatings of two nitride systems TiAlN and CrAlSiN, as well as a diamond-like carbon coating (DLC) with a gradient distribution of carbon electronic configurations sp2 and sp3 in depth. The coatings were applied to a substrate made of structural steel 12Cr2Ni4, subjected to carburization with a followed hardening and low tempering. Wear-resistant cemented surface layers of steel products are widely used in mechanical engineering as a contact surface in loaded friction units. Therefore, when conducting a comparative analysis, the mechanical and tribological properties of the cemented surface of the samples (without coatings) were used as a standard and were considered in the optimization process along with coatings. The work used a multi-parameter optimization technique in the form of an integral assessment of each material by constructing radial (ray) diagrams, which were based on a complex of eight characteristics, combining 4 physical-mechanical and 3 tribological properties, as well as the coating thickness parameter. The results of the analysis showed a consistent pattern: in terms of a complex of eight parameters, all coatings are significantly superior to the reference cemented layer. The CrAlSiN coating has the highest integral property indicator.

The present work investigates the strength properties of modified cement stone and polymer-cement compositions made from it. The control of the strength properties is achieved by recipe regulation of the mineral component of the multi-component binder. This makes it possible to significantly increase not only the strength of the materials, based on them, but also their reliability and durability. Dependencies, describing the influence of complex polymer additive consisting of superplasticiser, stabiliser and redispersible polymer powder on the strength of cement stone were obtained; coefficients reflecting the influence of polymers on the strength of cement stone were determined; functions of coefficient values depending on the dosage of additives were obtained. Based on the data obtained, a mathematical model of the strength properties of cement stone under the influence of complex additives was created. The developed multiplicative model for evaluating the influence of modifiers on the properties of polymer-cement composites allows to determine and predict the strength properties of polymer-cement composites to design composites with predetermined constructional properties.

The properties of burnt mine rocks are described. Compositions of asphalt concrete mixtures and asphalt concrete, based on materials from burnt mine rocks, have been developed, their physical and mechanical properties have been determined. Improvement of properties of experimental compositions of asphalt concrete is shown. The basics of the formation of the structure of asphalt concrete on materials from burnt rocks are outlined. Tests of experimental asphalt concrete mixes for the device of paving on experimental sites are carried out. Samples-cores from experimental sections of road surfaces were tested. The expediency of using mineral materials from burnt mine rocks in asphalt concrete mixtures and asphalt concrete has been confirmed.

Indonesia is the largest coconut fiber producing country in the world and has coconut plantation land with an area of close to 3.74 ha. The plantation products will be used to meet human needs, while the rest of the utilization will become waste. The process of destroying waste naturally usually takes place slowly, causing a pile of waste. Coconut fiber ash contains minerals consisting of silica, alumina, and iron oxides. This shows that coconut fiber ash has the potential to be used as a construction material. The previous research shows that the use of coconut fiber ash in large quantities as a cement substitute has the potential to reduce compression strength, so it cannot be utilized in large quantities. In this research, coconut fiber ash would be used as an added material and not as a cement substitute to utilize the waste as much as possible. This study would examine the influence of mortar characteristics on the addition of coconut fiber ash. The variation in the percentage of coconut fiber ash used is 0%, 2.5%, 5%, 7.5% and 10% to the weight of cement. The composition of mortar’s mixture would be based on SNI 03-6825-2002. The studied characteristics of the mortar are the following: density (unit weight), absorption and compression strength. From the result, it is concluded that the addition of coconut fiber in mortar mixture increases the density and the water absorption percentage. The optimum value of compression strength test result is 32.61 MPa, obtained from the mixture with the addition 2.5% of coconut fiber ash.

The paper proposes a tunable bandpass filter, the operating frequency of which in the range of 600–800 MHz is regulated by voltage. It is performed on a piezoelectric substrate made of lithium niobate and contains four parallel acoustic channels formed by two input interdigital transducers (IDTs), two multi-strip directional couplers and two output IDTs with the ability to switch each pair of acoustic channels with its independent vanadium dioxide film switch provides attenuation between channels of at least 70 dB. By using a special switch design based on a vanadium dioxide film and a coupler, we were able to reduce the control voltage to 0.1 V. The width of the vanadium dioxide film is no more than two periods of input IDT, which eliminates an increase in the SAW attenuation of s with an increase in the operating frequencies of the filter.

An electromagnetoelastic actuator is electromagnetomechanical device, intended for actuation of mechanisms, systems or management, based on the piezoelectric, piezomagnetic, electrostriction, magnetostriction effects, converts electric or magnetic signals into mechanical movement and force. The piezo actuator is used in vibration compensation and absorption systems in aircraft and rotorcraft elements, in nanotechnology research for scanning microscopy, in laser systems and ring gyroscopes. The structural scheme of an electromagnetoelastic actuator for nanotechnology research is constructed by using the equation of electromagnetoelasticity and the linear ordinary second-order differential equation of the actuator under various boundary conditions. An electromagnetoelastic actuator is using in nanotechnology, microelectronics, nanobiology, astronomy, nanophysics for the alignment, the reparation of the gravitation and temperature deformations. The nanomanipulator with the piezo actuator is applied in the matching systems in nanotechnology. In the present work, the problem of building the structural scheme of the electromagnetoelastic actuator is solving in difference from Mason’s electrical equivalent circuit. The transformation of the structural scheme under various boundary conditions of the actuator is considered. The matrix transfer function is calculated from the set of equations for the structural scheme of the electromagnetoelastic actuator in control system. This matrix transfer function for the deformation of the actuator is used in nanotechnology research. The structural schemes and the elastic compliances of the piezo actuators are obtained by voltage or current control. The structural scheme of the magnetostriction actuator is constructed for nanotechnology research. The characteristics of the piezo actuator are determined. The structural scheme of the piezo actuator with the back electromotive force is obtained. The transformation of the elastic compliances of the piezo actuators is considered for the voltage and current control.

In this paper, the research efforts are focused on energy generation from the midrange wind speed, that is 4–7 m/s. A new geometry has been designed to harvest the energy available in this range. The proposed geometry caters the advantages of both low and high wind velocity energy harvesters and tries to eradicate the disadvantage offered by these two harvesters in capturing the energy from mid- range wind speeds. Further, a mathematical model is prepared to show the potential of the new geometry for energy generation. It is found that the proposed design is suitable to generate significant amount of power from mid-range wind velocity.

A scissor-mechanism piezoelectric transducer is proposed to harvest the energy from the vibrations of the suspension system of the motorbike while running on the road surface. For system feasibility, the transducer is coupled with the wheel (unsprung mass) to the chassis (sprung mass) of the motorbike and equivalently modeled as a dual-mass spring-damper system to develop the mathematical model for energy harvesting. In the temporal domain, the charge, voltage, and current are calculated, considering the different classes of road roughness. The effects of the various parameters, such as the scissor angle, width, and thickness of the PZT bar, the velocity of the motorbike, and road roughness coefficient on the root mean square (RMS) of the power are studied. The maximum amount of power of 110 W was calculated from the practical design of the harvester of four PZT bars with width and height of 15 mm.

The paper demonstrates the results of a study of lead-free solid solutions of BaTi1-xZrxO3 modified with AgNbO3. Solid solutions, obtained by two-stage solid-phase synthesis, have high density, and show signs of coexistence of several crystallographic phases. Widely blurred maxima are observed on the dependencies of the dielectric constant, which may be a consequence of the close temperatures of the phase transitions in BaTi1-xZrxO3 and AgNbO3. Low concentrations of AgNbO3 lead to a significant change in the shape of the dielectric hysteresis loops compared to BaTi1-xZrxO3. At low concentrations of AgNbO3, optimal energy harvesting conditions are achieved, showing ~ 0.085 J $$\cdot$$ · cm−3 and ~ 77% at an external field of 2 kV. Further increase in concentration leads to a decrease in efficiency and the level of harvested power. It is expedient to use the obtained data to optimize the processes of production of multicomponent lead-free ceramics, based on BaTi1-xZrxO3, and to obtain materials in which various types of ferroordering coexist.

In this work, the dependences of complex electromechanical parameters of rectangle-shaped piezoceramic elements on the aspect ratio, that is the ratio between length (W2) and width (W1) were studied and analyzed. Rectangle-shaped samples of the PZT type dense and porous piezoceramics with the aspect ratio G = W2/W1 in the range from 1 to 6 and equal thickness were prepared and studied. Dependences of complex piezoelectric (d31), electromechanical (k31), elastic (S11E) and dielectric (ε33T) coefficients on the aspect ratio G were measured and analyzed on the length-thickness extensional mode of rectangular piezoelements oscillations using the piezoelectric resonance analysis program (PRAP).

An alternative to dealing with climate change and technological advancements is the use of new and renewable energy. Fossil fuels, which have long been a source of power for many parts of life, are now running out because of constant use. The utilization of new and renewable energy has its roots in the excessive carbon dioxide emissions caused by fossil fuels. Sustainable organic resources can be used to create new, sustainable energy sources, including biomass fuels made from organic waste. Organic material created by a photosynthetic process is known as biomass, and it can take the form of waste or finished goods. Organic energy sources found in biomass can be transformed into a number of different forms. Bio-briquettes are one of them. One of the renewable resources that can be utilized as an alternative fuel, including for briquettes, is biomass. Coconut shell is one type of biomass that can be utilized as the primary ingredient in the production of briquettes. A potential waste that can be directly turned into briquettes is coconut shell. Briquettes made from coconut shell charcoal are produced through pyrolysis, crushing or grinding, mixing, compaction, and drying. Briquettes created from coconut shell charcoal have a number of benefits, including not producing smoke, producing a high degree of heat, being environmentally beneficial, and having a longer burning time.

The possibility of using magnetic nanoparticles of iron oxide (magnetite) Fe3O4(II, III) as a filler in the matrix of microcrystalline cellulose in the form of massive tablets, as well as in the liquid medium of polymethylsiloxane (phantom biological medium) in the form of suspension has been considered. The magnetic nanoparticles were approximately spherical in shape with an average size of 10–12 nm, some of them formed large agglomerates. We found that in the magnetization field in the range ± 200 μT, all samples had hysteresis-free behavior characteristic of superparamagnetic nanoparticles, and in the range ± 80 mT, hysteresis is observed on all samples. The samples were subjected to vibration exposure of 2000 prm for 1 min. In the modes “before vibration” and “after vibration” the values of the residual magnetic field and specific magnetic moment in massive samples differ insignificantly, while in suspensions these values change significantly by 1.5–12 times. In suspensions, the relaxation time of the residual magnetic field is 4.5–7.5 times shorter in the “after vibration” mode, which is mainly determined by the Brownian relaxation mechanism. In this work we emphasize the prospectivity of the studied magnetic nanoparticles in suspensions in theranostics of osteoarthritis diseases.

We consider a model of a keratoprosthesis with fastening in the cornea in the form of a “skirt” (haptic), the material of which is modeled as linearly elastic. The prosthesis is placed in the cornea, the material of which is modeled as a porous, moisture-saturated medium. Using the finite element method, the stress-strain state of the keratoprosthesis elements and the cornea is calculated. Three cases of haptic fixation in the cornea and its different sizes are considered. Based on numerical analysis, the parameters of the keratoprosthesis are determined at which it is less traumatic.

In recent years, the use of the optoacoustic effect in biomedicine has aroused great interest. This is due to the requirements in this area for harmless, non-invasive, real-time diagnostic procedures that provide effective therapeutic procedures. An algorithm for reconstructing the image of the structure of biological tissue with optoacoustic signal transformation based on neural networks has been developed. The reconstruction of the optoacoustic image based on the acoustic signal received from aggregated erythrocytes was performed.

A method for remote monitoring of the condition of gas and oil pipelines is proposed. It is based on the excitation of low-frequency vibrations in the pipeline wall. By using a bispectral approach, the recorded signal is transformed into graphical elements on a plane. This approach allows visualizing the control of signal changes by transforming the original amplitude-time signal into a specific point in two-dimensional space. The object of this study is a two-layer pipe, consisting of two pipes rigidly coupled. The outer pipe is intact, while the inner pipe contains a defect in the form of a through hole. The process of changing the condition of the pipe is simulated by changing the position of the inner pipe, weakened by the presence of a defect, within the outer pipe. The sizes of the pipes ensure their close contact with each other; on the other hand, they allow the movement of the defect location. Changing the position of the defect allows changing the parameters of the system and thus affecting the structure of the surface wave field. The aim of the study is to develop a method for detecting changes in the position of the defect by changes in the surface wave field. The proposed method allows visualizing the control of changes in the position of the defect. Any change in the position of the defect leads to a change in the position of the point in feature space. This makes it possible to monitor changes in defect parameters based on the position of the point on the plane. The conducted research have established a high sensitivity of the proposed approach to changes in damage to the pipe wall.

Heat exchange equipment of various types makes up a significant part of technological equipment in the gas and petrochemical industries. This is explained by the fact that almost all technological processes in the oil refining and petrochemical industries (heating, rectification, drying, evaporation, etc.) are connected, in one way or another, with the need to supply or remove heat. The purpose of this work is to analyze heat exchangers used in petrochemistry, develop a methodology for calculating heat exchangers, review existing mathematical models of heat exchange processes and formulate corresponding boundary value problems, develop a mathematical model that allows calculating temperature profiles at heating fuel oil with water vapor in a single-pass tubular heat exchanger along the length of the heat exchanger. As part of the research, mathematical models of the thermal field were created and implemented at heating fuel oil with water vapor in a single-pass tubular heat exchanger, depending on the design, geometric sizes, and operating conditions of the heat exchanger. The proposed mathematical models can be used to select the optimal parameters of the heat exchanger and the optimal rate of pumping fuel oil in the heat exchanger, which will ensure a sufficiently high heat transfer coefficient and not too large pressure losses.

As part of many units of the oil and gas industry, a manifold is used, which is an element of drilling equipment, included in the design of oil and gas fittings and represented by a whole block of pipelines and valves. Even though most of its components are formed by standard parts, the manifold is unique for each individual design due to the different arrangement of the equipment elements, which necessitates the study of the correctness of its functioning in each specific case. The purpose of this study is to check the strength of the attachment points of the manifold, which determine its overall performance. The objectives of the study are to carry out strength calculations of the fastening points of the manifold to determine their suitability for high-pressure operation, as well as automatic calculation of the flange connection. A 3D model of the manifold of a mobile pumping unit for hydraulic fracturing was used for the study. To determine the strength characteristics, the connection section of the high-pressure manifold transition coil with the pump by means of a flange connection was considered. For this unit, the strength calculation is performed according to Russian GOST 52857.4–2007. For the possibility of conducting the necessary studies in the design and optimization of the parameters of the flange connection, it is proposed to automate the calculation of the strength of flange connections. The computer-aided design system PTC Mathcad was used to automate the calculation. To find the coefficients presented in the standard in the form of graphical dependencies, they were translated into empirical formulae. The obtained results allow us to take the necessary coefficients in the calculation as input parameters and fully automate the calculation. The completed studies may be of interest to students and mechanical engineers who produce similar calculations.

In the oil and gas industry of a number of countries, long-life fields contain a significant amount of hard-to-recover hydrocarbon reserves, the production of which has been hampered by a lack of technology. Reactivation of old wells and stimulation of new wells is a topical issue today. The most effective technology is hydraulic fracturing. For fracturing operations, it is necessary to use modern and reliable equipment, an important part of which is a mobile high-pressure pumping unit. The purpose of this study is to improve the technical and economic parameters of the mobile pumping unit design under different types of external loads. The tasks of the research are selection of the drive part of the high-pressure plunger pump NP 720 with the weighting of the units on the chassis KamAZ 63501 and design of the superframe structure with the use of strength analysis methods in CAE-system. The method of automatic selection of the operating mode of the drive part of the plunger pump is developed, by means of which it is possible to calculate on what gear and at how many engine revolutions the necessary operating conditions for each pump mode will be fulfilled on the base of the given values of torque, speed of rotation of the pump input shaft, as well as gear ratios of the built-in gearbox and automatic gearbox. The method of calculation of the number of places of superstructure fastenings on the chassis is proposed, which is based on the strength calculation of bolt connection on shear. Using the overload experienced by the superstructure and its total weight, changing the diameter of bolts from standard values, the minimum number of fasteners was calculated. Using the finite element method in the MathCad system of mathematical calculations, a statically indeterminate beam was calculated using the finite element method, which was used to determine the optimal location of the fastening nodes of the subframe of the mobile pumping unit.

Surabaya is one of the many coastal areas in Indonesia which is an archipelago country. Land use changes have affected the coastal Surabaya. For several decades, there have been changes in land cover on the coastal Surabaya, especially in East Surabaya. Initially the coastal area was a mangrove conservation area, but the land function changed to become a pond area and residential area (urban area). The functions of these lands influence each other so that the coastline of Surabaya also changes. Remote sensing satellite imagery data can help to monitor coastal areas both land cover and coastline. In this research, we used Landsat satellite image data 1994–2023. The method used to classify land cover is the guided classification method (Maximum Likelihood) while to determine the speed of shoreline change using tools in ArcGIS, namely the Digital Shoreline Analysis System (DSAS). The purpose in this research is to determine changes in land cover and determine the rate of change of the coastline in Surabaya (erosion and accretion). Monitoring the Surabaya coastal area is needed to determine the correlation of changes in the coastal area to socio-economic aspects so that it becomes a recommendation for better coastal area management for the Surabaya area.

Items made of iron that have been left unattended or neglected for years will usually have a reddish-brown surface. This is a sign that the iron has rusted. Rust on iron is formed due to a reaction between iron and oxygen in the presence of water or moisture in the air. The reddish-brown color is the result of an oxidation process with the scientific name of iron oxide (Fe2O3). Batik is a pictorial fabric, and the process of making it is specifically done by drawing or applying motifs to a plain or blank cloth, then carrying out a special process so that the cloth has special characteristics. Teyeng batik is a new innovation in making motifs on batik using iron rust stains. The rusting process is intended to give a rust pattern to the plain cloth to be used as batik. This process forms the basic motifs of batik cloth. To create rust stains on batik cloth, iron and wire are used, such as scrap iron trellis, ram wire, gabion wire, or other similar materials. The shape of the wire used and the way it is arranged on the cloth will make the rust motifs different from one another. Rust stains resulting from the trellis will form straight lines, like connecting lines. Rust stains from granulated iron and ram wire will give fabrics a dirty or old appearance and leave small squares of stains. Stains from the gabion wire will produce an irregular diamond-shaped pattern like snake scales.

Furniture SMEs production activities need a balance between the supply of wood raw materials and the need for furniture products. The amount of wood raw materials in the forest is limited, so furniture production activities must be controlled properly, so that the supply chain balance of furniture products starting from wood raw materials, production activities, and products received by consumers is maintained properly. Furniture SMEs must carry out production activities in accordance with realistic demands. There is too much and too less furniture production, so it has an impact on other aspects that are interrelated, and a balance between supply and demand is needed. The Fuzzy Goal Programming (FGP) method is appropriate for making decisions to determine how much raw materials should be provided by Indonesian Forest Companies using the FGP model. The FGP method can maximize or minimize the resources owned by Furniture SMEs by using several objective functions and constraint functions. SMEs furniture products include cupboards, sideboards, and beds. The FGP method can provide precise and clear information on the optimal amount of production so that no losses are received by furniture SMEs. Based on the data analysis, the results show a fuzzy value of 0.98, so the profit opportunities for furniture SMEs are very high and provide many benefits for the development of furniture SMEs.