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A physically non-linear Maxwell-type constitutive relation with two material functions for nonaging elasto-viscoplastic materials is studied analytically in order to examine the set of basic rheological phenomena that it simulates, to enclose its application field, to obtain necessary phenomenological restrictions which should be imposed on its material functions and to develop identification and validation techniques. Characteristic features of loading-unloading-recovery curves family produced by the model with two power material functions (with four parameters) under loading and unloading at constant stress rates and subsequent rest are analyzed in uni-axial case and compared to general properties of stress-strain-recovery curves produced by the constitutive relation with two arbitrary (increasing) material functions (theorems 1 and 2). Their dependences on loading rate, maximal stress and material functions exponents are examined. Power functions are the most popular in creep models, elastoviscoplasticity, polymer rheology, hydrodinamics of non-newtonian fluids and simulation of superplastic flow. The analysis reveals several specific properties of theoretic loading-unloading-recovery curves produced by power model with four parameters that can be employed as the model applicability indicators which are convenient for check using test data of a material. They should be checked in addition to general applicability indicators for the Maxwell-type constitutive relation with two arbitrary material functions. A number of effective calibration procedures for the model in the class of power material functions are developed. They are more rapid and effective than general identification techniques for two arbitrary material functions developed previously. The first procedure employs a pair of stress-strain curves at different stress rates, the second one is based on a pair of loadingunloading- recovery curves with various maximal stress values and loading rates and the third one needs only one loading-unloading-recovery curve. The explicit expressions are derived for four material parameters via test data. They enable separate and direct evaluation of the material parameters without error accumulation. Identification techniques versions are considered and their advantages and shortcomings are discussed. The ways to minimize the error using additional tests are proposed.

The paper is devoted to modern experimental and computational studies analysis on the point of asymmetric destruction of ice on the surfaces of the working blades of gas-turbine engine blades. A schematic diagram of an experimental setup has been developed, which consists of the following main elements: a wind tunnel, a cold chamber, a model fan, an electric motor, and a high-speed video camera. The experimental setup makes it possible to carry out laboratory studies of the ice formation and destruction processes. The choice of the experimental test rig parameters was made to allow assessing the icing of the blades of a rotating fan, which reproduces the processes occurring on gas turbine engines. Based on the results of three-dimensional gas-dynamic and strength calculations, the design and basic geometrical parameters of the flow path and the dummy fan were determined. The dependences of compression ratio Pk and the power consumption of a model fan Wcons on the value of the mass air flow Gair for a different number of rotor blades are presented. The choice of materials for the disk hub and blades of a dummy fan which experience tensile and bending loads at high rotation speeds up to 12.000 rpm was made, that satisfies the conditions of static and dynamic strength, also the allowable safety factors were evaluated, and pressure characteristics were obtained.

In the problems of technological mechanics: the manufacture of structures from composites, packaging and deployment of products from prepreg for space purposes, and others, it becomes necessary to calculate the current mechanical properties of a composite material with an incompletely cured binder. Such properties are determined primarily by the binder state, which may be described by the conversion kinetic equation. The parameters of the kinetic equation depend on many factors: temperature, diffusion, the presence of a catalytic system, modifiers, reagents, the formation of by-products of kinetic reactions, the evaporation of reagents, the effect of radiation, etc. Reliable consideration of the influence of each factor in the kinetic equation turns out to be practically impossible. Therefore, most authors use the phenomenological conversion equation based on experimental data, since these data reflect all the features of the kinetic process. We consider the first order conversion equation, which takes into account auto-acceleration and auto-deceleration. The equation parameters are determined on the basis of isothermal experimental data by the following method. The equation for the conversion rate is integrated, the integral is used to construct a system of equations containing experimental data and the desired approximation parameters, which are determined by standard mathematical methods. The dependence of the kinetic equation parameters on temperature is also constructed by approximation. Examples of constructing conversion equations for a two-component and industrial multicomponent Barnes mixture are given. It is shown that the parameters of the kinetic equation in both cases significantly depend on temperature, and for a multicomponent mixture this dependence is more complicated due to the simultaneous implementation of several reactions. Examples of using the obtained kinetic equation to calculate the curing degree of samples under a given temperature loading are given.

Composite materials reinforced with synthetic fibres have been used in aviation and space technology for more than half a century. Fibre-reinforced composites with high specific strength and corrosion resistance are an attractive alternative to traditional structural materials, including steels, aluminium and titanium alloys. At the same time, composites based on carbon and glass fibres are inherently brittle structural materials with high strength sensitivity to stress concentrations due to the design features of the structures or defects that occur in operation. One way to solve this problem is hybridisation which makes it possible to increase the nonlinearity of the composite stress-strain diagram and reduce sensitivity to notches. Hybrid composites combine several types of reinforcing filler with different fracture strains and exhibit a pronounced pseudo-ductile plateau in tension. Such material behaviour ensures the redistribution of stresses near the concentrator and potentially reduce notch sensitivity. When designing hybrids, it is necessary to take into account the influence of different factors including the ratio between the components and their lay-up, using various technological methods, and the specific strength of the finished material. This paper presents the results of an experimental study on the strength of hybrid composites based on glass and carbon fabrics in the open hole tests. It was found that hybrids with an extended hardening area after the pseudo-yield plateau are were more notch sensitive. A low elongation component layers rotation on angles up to 10°, as well as the use of thin polymer veils, also reduce the sensitivity of the composite strength to the presence of the defects.

The paper is devoted to the numerical analysis of uniaxial loading of a sample of the mechanical metamaterial. The structure of the mechanical metamaterial is constructed of a ring and four ligaments, which make up a tetrachiral structure. The peculiarity of such a structure consists in torsion of the sample under the force load. Two methods of connecting cells in the metamaterial are considered: "adjoining" and "overlapping". The "adjoining" method of joining cells increases the thickness of the internal structure of the sample, which allows us to consider it as a topological defect of the metamaterial. The "overlapping" method saves the base material from which the tetrachiral structure is constructed. Differences in the structure when constructing a three-dimensional sample result in a significant change in the characteristics of the sample. Numerical solution of the problem is performed in a three-dimensional formulation using the finite element method. The constitutive relation describing the behavior of the model corresponds to Hooke's law. Numerical simulation of uniaxial loading made it possible to obtain the results of mechanical response and to analyze the effective properties of metamaterials. A topological defect in the form of a thickening of the internal structure elements led to a difference in the linear dimensions of the two samples. The increased thickness of the unit cell connection elements resulted in a decrease in the effective density of the metamaterial sample. The same sample showed a triple increase in the value of the elastic modulus. The greater ability to resist deformation resulted in a reduced twist effect compared to the sample whose cells were joined by the "overlapping" method. The results obtained will make it possible to program the mechanical behavior and properties of the metamaterial sample.

The paper deals with the identification of a crack-like defect in a coated wedge based on ultrasonic nondestructive testing. The authors propose an approach of defect identification followed by determination of its geometrical parameters. The approach is based on a shadowed ultrasonic nondestructive testing method combined with deep machine learning technologies. A wedge-shaped area is inspected for the presence of an internal defect. On one edge of the wedge there is a source of ultrasonic vibrations, on the opposite edge there is a receiver. Passing through the coating and body of the wedge, part of the signal is reflected from inhomogeneities and defects that may be present in it. The signal reaching the opposite edge of the wedge is read by the receiver. The received data is processed by a neural network model, which predicts the presence or absence of an internal defect and, if present, determines geometric parameters such as size and position. A finite element model of ultrasonic wave propagation inside the wedge is constructed. Special damping layers are used, due to which the influence of parasitic signal reflections and its further propagation into the wedge body is significantly reduced. Based on the built model, the shadow method of ultrasonic scanning is implemented. This method implies that on one side of the wedge are installed excitation devices, and on the opposite side – receiving devices. Several numerical experiments for various combinations of geometric parameters of the wedge and the defect have been performed using a distributed computing system. Based on the obtained data, a neural network model was built and trained, capable of identifying the defect and determining its characteristics. The input of the model is spectrograms of the readout signal, and the output is values characterizing the defect.

The strength of a square plate with a central crack at normal separation was studied within the framework of the Neuber–Novozhilov approach using a modified Leonov–Panasyuk–Dugdale model using an additional parameter, the diameter of the plasticity zone (width of the pre-fracture zone). As a model of a deformable solid body, a model of an ideal elastic-plastic material with a limiting relative elongation was chosen. This class of materials includes, for example, low-alloy steels used in structures operating at temperatures below the cold brittleness threshold. In the presence of a singular feature in the stress field in the vicinity of the crack tip, it is proposed to use a two-parameter discrete integral strength criterion. The deformation fracture criterion is formulated at the tip of a real crack, and the force criterion for normal stresses, taking into account averaging, is formulated at the tip of a model crack. The lengths of real and model cracks differ by the length of the pre-fracture zone. The constitutive equations of the analytical model are analyzed in detail depending on the characteristic linear dimension of the material structure. Simple formulas suitable for verification calculations for the critical breaking load and the length of the pre-fracture zone are obtained. Numerical modeling of the propagation of plasticity zones in square plates under quasi-static loading has been performed. In the numerical model, the updated Lagrangian formulation of the equations of mechanics of a deformable solid body is used, which is most preferable for modeling the deformation of bodies made of an elastic-plastic material at large deformation. The plastic zone in the vicinity of the crack tip is obtained by the finite element method. The results of analytical and numerical prediction of plate fracture under plane deformation are compared. It is shown that the results of numerical experiments are in good agreement with the results of calculations using the analytical model of fracture of materials with a structure under normal separation. Diagrams of quasi-brittle and quasi-ductile fracture of a structured plate are constructed.

The paper discusses the method of obtaining a digital passport of the material and the development of a digital twin of the product at various stages of its manufacture. The object of research is a conical mesh structure. The subject of research is the processes occurring in the product at the manufacturing stages. The following main stages of creating a mesh structure were considered in the work: 3D printing of a workpiece tooling, laying out a carbon unidirectional material, heating and impregnation of the preform with a binder, polymerization of the binder, and warpage of the product geometry. An algorithm for determining the properties of materials and their calibration using modern software and hardware and universal equipment was described. Modeling of the tooling 3D printing process was carried out in the Ansys software package. Step-by-step technological modeling of the transfer molding process was carried out using the ESI PAM-COMPOSITE software package. The result of the simulation is the optimal technological manufacturing parameters and the geometry of the shaping tooling with anticipation of warping.

The article is devoted to solving the urgent problem of improving the method of nondestructive testing of the condition of non-rigid road clothes. In addition to the previously developed approach to determining the mechanical parameters of materials of structural layers of nonrigid road coverings based on solving the inverse coefficient problem of restoring operational elastic modules providing specified displacement fields, an approach was developed that allows determining the parameters of energy dissipation in the structure of multilayer road pavement based on the correction of dynamic hysteresis loops recorded in the field and calculated using mathematical model of dynamic VAT. The article presents the results of numerical simulation of dynamic hysteresis loops for two different variants of multilayer structures. The possibilities of correcting the shape of hysteresis loops and their area by varying the tangents of the energy loss angles in layers of a multilayer medium and the elastic modulus of a homogeneous half-space are shown. The complex correction of the elastic modulus values of the structural layers of road clothes and the calculated loops of dynamic hysteresis made it possible to fully take into account the processes of energy attenuation at a distance from the point of application of the load. During the correction, it was found that the values of the elastic modulus of the road layers and the tangents of the loss angles in them have a complex effect on the areas of dynamic hysteresis loops and the nature of energy attenuation at a distance from the point of application of the load. At the same time, the elastic modulus of the underlying half-space is not limited in thickness to the greatest extent on the area of dynamic hysteresis loops (which led to an increase in the elastic modulus of the underlying half-space from 120 and 150 MPa for road construction variants with a reinforced and non-reinforced base to 170 and 160 MPa, respectively), and a decrease in the dissipated energy at a distance from the point of application This is primarily due to the tangent of the angle of energy loss in the half-space. The obtained values of the tangents of the loss angles are obviously related to the patterns of energy dissipation at the boundaries of the contacting layers of the pavement, and also take into account all possible anomalies and delaminations in the calculated structures. Within the framework of this article, calculated hysteresis loops on the surface of the pavement were obtained for the first time, the deformation energy was calculated based on their areas, and the possibility of their comparison with those registered experimentally was proved.

To select rational parameters of the process of hybrid additive manufacturing of structures made of structural metal alloys and stainless steels, mechanical characteristics capable of serving as indicators of material quality were determined. The most advanced technologies of additive manufacturing by wire-arc surfacing (plasma, plasma arc with a melting electrode, including cold metal transfer) with layer-by-layer forging with a pneumatic impact tool and subsequent heat treatment were used. Aluminum-magnesium alloy AlMg5, titanium alloy Ti-6Al-4V, austenitic stainless steels 12Cr18Ni10Ti (AISI 321) and AISI 308LSi have been studied. Samples were cut from the blanks created by additive manufacturing – blades for standard tests for static uniaxial tension and cylinders for high-speed compression tests by the Kolsky method on a Hopkinson split bar. According to the registered and processed stress–strain curves for all materials, standard strength and ductility characteristics and the Johnson – Cook law of deformation and speed hardening were determined. For a correct assessment of the mechanical properties of additively produced materials, these tests were also carried out for each of them in the form of annealed rolled products. It is established that to compare the efficiency of various technological parameters of additive manufacturing, it is advisable to use static tensile strength and uniform elongation to rupture, having the smallest statistical variation. It was also found acceptable to approximate the Johnson – Cook law of the deformation curves of each of the studied materials according to averaged data, including various technological modes. Certain mechanical characteristics seem to be necessary for the search for effective modes of hybrid additive manufacturing and numerical calculation of various elastic-plastic problems in a dynamic formulation for the studied materials for design and technological needs.

The present research is devoted to the development of the theoretical foundations of nondestructive acoustic method for identifying inhomogeneous prestress fields in a hollow cylinder, depending on the probing loading type. A linearized model of steady oscillations of an elastic body in the presence of an inhomogeneous prestress field of arbitrary nature is considered in the standard and weak formulations. On the basis of this model, we formulate a problem for a cantilever-clamped prestressed hollow cylinder that performs steady axisymmetric vibrations under three types of probing loading. A corresponding weak formulation of the problem in the cylindrical coordinate system is presented, in which six independent components of the prestress tensor are taken into account. At that, a case of prestress fields obtained by applying some initial mechanical external static load is considered. In the presence and absence of prestresses of various types, amplitude-frequency dependences are analyzed, and resonant and natural frequencies are found in a wide frequency range. Numerical calculations were carried out using the FEM on a non-uniform grid; mesh refinement is carried out in the vicinity of the boundary points, where the type of boundary conditions changes. Based on the numerical solution of an auxiliary set of direct problems, seven types of prestress fields are constructed, differing in the types of initial loading, most often encountered in practice. To assess the possibility of implementing the procedure for reconstructing prestresses of each of the considered types, a sensitivity analysis was additionally performed, which showed that for some prestress types there are frequencies and types of probing loading for which the presence of prestress is practically not manifested. The sensitivity analysis performed made it possible to implement the optimal method of probing loading when solving the inverse coefficient problem. The statement of the new inverse problem on the restoration of arbitrary inhomogeneous prestress fields in the considered finite hollow cylinder is formulated. When restoring the prestress of a given structure, the inverse problem is reduced to finding a set of parameters from an ill-conditioned algebraic system, which was studied with the help of the A.N. Tikhonov regularization method. Additional data for solving the inverse problem was obtained on the basis of probing both via a single load and via combined probing modes. It has been found that it is most effective to use a combined loading mode and use a sufficiently wide frequency range when selecting sounding frequencies. The results of computational experiments on the reconstruction of six components of the prestress tensor are presented and analyzed, and recommendations are proposed for choosing the optimal modes of acoustic sounding.

In this paper, symmetric and antisymmetric plane problems about the action of oscillating load on the boundary of an elastic isotropic nanothin layer are considered. The nanoscale layer thickness is considered by introducing surface stresses in accordance with the Gurtin-Murdoch theory. According to this theory, it is assumed that, in addition to external loads, surface stresses act on the layer boundaries, which are described by Hooke's “surface” law. As a result, the properties of the elastic material of the layer with nanoscale thickness become different from the properties of the material of a regular-sized body, which is typical for nanomechanics problems. A standard technique was used for the solution of formulated problems, including the application of limiting absorption principle, the Fourier transform over infinitely extended coordinate and the theory of residues for finding the inverse Fourier transform. It is shown how it is possible to obtain solutions in the form of series in natural waves, in which the wave numbers are defined as the roots of the corresponding dispersion equations. For a specific example, dispersion relations were studied and graphs of the first dispersion curves were plotted. The behavior of barrier frequencies, changes in wave numbers and zones of existence of backward waves at different nanoscale layer thicknesses are analyzed. The results of the analysis showed that for an ultrathin layer, surface effects have a significant impact on the dispersion relations, and the trends in the dispersion curves can differ significantly for different modes and layer thicknesses.

The use of C60 fullerites to create films on the surface of a solid substrate can be used not only to create coatings, but also to modify the surface layer of the substrate, which from a practical point of view can be in demand in such sectors of the economy as machine and instrument engineering. To analyze the process of formation of fullerite films on the substrate surface, a computer experiment was carried out, but the behavior of not a single fullerite or fullerene, as it was implemented in previous works of the authors, but a significant number of C60 fullerites deposited in the modeling area over a certain time interval and forming a "flow" was modeled. The substrate of the solid was an iron crystal Fe(100). The substrate temperature in the study was kept constant at the following values – 300 K, 700 K, 1150 K. The initial parameters of each individual fullerite were determined stochastically within the specified limits. The software package used to conduct the described computer experiment was – LAMMPS. The interaction of the atoms of the system with each other, during the simulation, was determined by the multiparticle potential (MEAM is a modified submerged atom method). The main result of the conducted computer experiment is that it was possible to simulate the deposition of C60 fullerites with the formation of a film on a solid substrate. The main regularities of the interaction of fullerite as a whole and fullerenes forming it, both with the substrate and with other fullerites forming the film, were revealed. And the analysis of changes in temperature and potential energy of the system, both during the deposition of fullerites and after its completion, allows us to talk about the stability of the resulting fullerite – substrate system.

In the deformable solid mechanics, there are concepts associated with continuum points (displacements, relative elongations, shifts) and a set of continuum points – an elementary volume (mass, energy, stresses). The role of such volume in the mechanics of composite materials is played by the representative volume element (RVE).This concept was first introduced by R. Hill (1963). Modern authors use the W.J. Drugan, J.R. Willis (1996) formulation. Based on the analysis of the RVE concept, we formulated its essential features: RVE is the minimum possible sample for numerical tests to determine the effective material parameters of the composite; under any RVE loading, its macroscopic stress-strain state is uniform. Its significance for the mechanics of composite materials is revealed: the existence of RVE for a composite is a criterion for applying the effective modulus theory to the analysis of its stress-strain state; the dehomogenization of a stressed-state composite material at a point is a solution to the micromechanics problem of the RVE stress-strain state determination; the characteristic size of RVE limits the size of the sampling grid in the numerical study. An iterative algorithm for constructing a representative volume of a periodic structure composite and its effective material thermoelastic characteristics is proposed. It is shown that the geometric shape of such a composition is a rectangular parallelepiped. The RVE construction algorithm for periodic compositions is extended to the composites statistically uniformly reinforced with continuous fibers. A method for modeling such materials with a following regular structure is suggested described: in the section perpendicular to the fibers, fiber centers should be located at the vertices of regular triangles. Examples of constructing RVE and thermoelastic material characteristics of specific compositions are given. The calculation results are compared with the data obtained using certified software products.

Background: 2D nanostructures are greatly interested in different technological applications, particularly optoelectronics. Tin oxide 2D nanostructures have shown great transparency and ideal charge carrier transport properties. Objective: The current study aims to evaluate the main characteristics of 2D-nanostructures observed during the synthesis of hydrated forms of tin oxide (II) or (IV) doped with Mn. Methods: A chemical co-precipitation method was used for the synthesis of the hydrated forms of tin oxide (II) or (IV) with different conditions on time (1 and 1.5 h) and temperature (60ºC and 90ºC), using MnCl2 as the manganese source. Results: X-ray diffraction and XPS results revealed the formation of the hydroromarchite phase (Sn6O4(OH)4) as the main product of the synthesis reaction. Scanning electron microscopy images were used to identify and measure, in a first approach, the 2D nanostructures observed as a result of the synthesis. Morphological characterization using different transmission electron microscopy techniques revealed the presence of nanoparticles that were observed to self-assemble to form the 2D nanostructures observed (nanorods and nanosheets). Nonetheless, selected-area electron diffraction suggested the presence of the cassiterite phase (SnO2) in the nanoparticles forming the 2D nanostructures. Furthermore, chemical analyses using energy-dispersive X-ray spectroscopy supported the observations made by the diffraction studies regarding the presence of cassiterite phase (SnO2) in the 2D nanostructures. The number of 2D nanostructures observed in the analyzed samples increased as the Mn concentration increased in the synthesis reaction. Conclusions: The addition of Mn as an intended doping element increased the crystallite size and the polycrystallinity of the synthesized hydrated forms of tin oxide (II) or (IV). Additionally, it also promoted the formation of 2D nanostructures made of SnO2 nanoparticles.

Background: The evolution of environmentally-safe methods for treating hazardous chemicals in wastewater, particularly urban and industrial wastewater, has increased interest over recent years. The chromium-containing wastewater is produced by industries from steel, metallurgical, electroplating, chemical, refractory, leather tanning, dye manufacturing, mining, cementing, textiles, etc. Consequently, advanced techniques are essential for treating chromium-polluted water. Objective: The prime objective of this effort was to assess the adsorption performance of nanoTiO2 (nanoparticles of average crystallite size 19.15 nm) doped strong base anion exchange resin (TDTulsion) for Cr(VI)to that of the host Tulsion A-62 (MP). Methods: The tests were carried out in batches in the temperature-controlled water bath shaking unit, with 30 ml of the aqueous solution containing Cr(VI) and a certain amount of resin being stirred for 6 hours at 303 K. Using a standard diphenylcarbazide (DPC) procedure at 540 nm, the solution was spectrophotometrically analyzed for Cr(VI). Results: The majority of the Cr(VI) ions are adsorbed by the anion exchange resins Tulsion A- 62(MP), and TD-Tulsion is in the pH range of 4.0 to 5.0. The maximal sorption capacity of Cr (VI) was established to be 181.5 and 204.8 mg/g for Tulsion A-62(MP) and TD-Tulsion, respectively. Conclusion: The TD-Tulsion has a substantially better adsorption capacity than Tulsion A-62(MP) under similar conditions. The outcomes show that modifying anion-exchange resin with nano titanium dioxide improves adsorption performance in Cr(VI) removal from drinking water and contaminated water.

Abstract: Nanofluids are a new class of nanomaterials suspended in a base liquid. Nanofluids have shown extremely distinctive properties that give tremendous opportunities for a wide range of applications. Nanofluids are a novel group of heat transfer fluids that have attracted the attention of researchers from various fields due to their intensive thermal properties. This systematic review highlights the synthesis, stability, physical treatment, and applications of nanofluids in various sectors. Applications of nanofluids in different sectors like the coolant in machinery, cooling of electronics, in chillers, cooling of diesel electronics generators, in a boiler cool gas reductions, and the manufacturing industry. The manufacturing process is one of the most fundamental and well-proven industrial processes in product-based industries. Cutting fluids play a critical function in lowering manufacturing cycle time as well as cutting costs during the machining process. A review of the importance of the machining process, as well as the use of nanofluids as cutting fluids, has been investigated in this work. To achieve these goals, cutting force, surface quality, tool and workpiece interface temperature, tool geometry, and the impacts of environmental situations were studied. Various vital specifications, such as the type of nanoparticle, a cutting tool used, work material type, and machining processes like turning, milling, drilling, and grinding were studied and thoroughly summarised in this work. If the machining parameters were used correctly, a greater heat transfer rate would be observed due to changes in lubricating characteristics and physical parameters.

Abstract: The fabrication of polymer fibre blends has gained much attention for the development of innovative nanomaterials. Polymer fibre blends are nanomaterials with different functionalities and properties such as a sizeable surface-to-area ratio, high porosity, flexibility, and stability. The focus of this study was to produce zein/PVA fibre blends using the electrospinning technique and varying parameters such as concentration and applied voltage. The two parameters are key driving factors for the production of fibres. Zein as a natural polymer has challenges in developing fibre materials which require artificial polymer like PVA to create a good blending mixture for electrospinning. Methods: The zein/PVA nanofibre blends were fabricated using the electrospinning technique. The FE-SEM (Leo, Zeiss) was used to study the surface morphologies of the zein/PVA nanofibers blends. The optical properties of the nanofibre blends were determined using the UV-vis spectrophotometer and the chemical structure and composition of zein/PVA nanofibers blends were studied using Thermo Scientific Nicolet iS50-FTIR spectrometer, universal ATR with the diamond detector. Results: The SEM images showed smooth zein/PVA ribbon-like nanofibre blends of 90/10, 80/20, 70/30, 60/40, and 50/50. SEM images of zein/PVA (80/20) electrospun at 25 kV were obtained to be the maximum fibre yield due to zein/PVA compatibility, increased conductivity, and enhanced fibre formation. The optical properties (absorption spectroscopy) suggested that the zein/PVA (80/20) fibre blend was miscible, and the FTIR spectra confirmed their functional groups. Therefore, the characterization results showed that the polymer blended solutions concentration and applied voltage increment affected fibre size distribution and morphology. Conclusion: Optimizing concentration and applied voltage successfully produced smooth, uniform bead-free zein/PVA fibre blends as parameters are increased.

Abstract: Nanotechnology has enabled sensors to detect and sense a very small amount of chemical vapors. Sensors play a major role in our daily life. The use of sensors has made human life easy. One such type of sensor is the Gas sensor made up of Semiconducting metal oxides. These sensors have their own unique features which help in the easy monitoring of toxic gases. Out of all the metal oxide present, the gas sensors made up of ZnO nanostructures are mostly used in the gas sensing industry. ZnO has become a research hotspot of gas-sensing material because of the variation in resistance observed on the surface. These resistance changes are observed due to the adsorption & desorption of gases. In this review, we will be discussing the ZnO nanostructures, their preparation and their applications in the sensing of various toxic and flammable gases.

Abstract: Nanotechnology is a promising science with new aspects to fight and prevent various diseases using nanomaterials. The capability to expose the structure and functions of biosystems at the nanoscale level supports research leading to development in biology, biotechnology, medicine and healthcare. This is predominantly advantageous in treating microbial infections as an alternative to antibiotics. However, widespread production, and use and misuse of antibiotics have led to the emergence of multiple-drug resistant (MDR) pathogenic bacteria. Due to infectious diseases from these drug-resistant pathogenic strains, human mortality rates have consistently increased and are becoming an epidemic in our society. Consequently, there is a strong demand for developing novel strategies and new materials that can cope with these problems. The emergence of nanotechnology has created many new antimicrobial options. The small size of these nanomaterials is suitable for carrying out biological operations. Several metals and metal oxides, such as silver, copper, gold, zinc oxide and iron oxide nanoparticle types, have shown toxicity toward several pathogenic microbes. Metal-based nanoparticles have been broadly examined for a set of biomedical applications. According to the World Health Organization, the reduced size and selectivity of metal-based nanoparticles for bacteria have established them to be effective against pathogens, causing concern. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms, which not only make the development of resistance by bacteria difficult, but also widen the spectrum of antibacterial activity. Metal-based nanoparticle efficiency studies achieved so far have revealed promising results against both Gram-positive and Gram-negative bacteria. Here we discuss the potential nanomaterials to either treat microbial resistance or induce the development of resistance. However, fundamental research is required to focus on the molecular mechanism causing the antimicrobial activity of nanomaterials.

Abstract: The eye is a complex organ in the body containing a repertoire of metabolite indicators such as glucose, peptides, specialized ions, and many critical biological data such as intraocular pressure (IOP), corneal temperature, and pH. Contact lens research and patient care have progressed substantially throughout the last three decades; hence smart contact lenses were developed with significant advancements in material biocompatibility, better lens layouts, the healthcare system, and more flexible and efficient modalities. Smart contact lenses are adjustable sophisticated visual prosthesis devices that monitor various significant physical and biochemical changes in ocular disorders, which are noninvasive and continuous. Wearable systems that utilize bodily fluids like sweat tears, saliva, and electrochemical interactions with steady physiological state and illness monitoring are currently developing. Because of its ease of access, fabrication, and noninvasiveness, tear fluid is commonly used to assess ocular disorders, blood glucose, and even cancers. Furthermore, the integration of nanotechnology into contact lenses has emerged as a promising platform for noninvasive point-of-care diagnostics. Utilizing nano-based contact lenses for ocular drug delivery is a new study area in bioengineering and innovative medical techniques. Despite all of the research done in this area, new technologies are still in their early stages of development, and more work in terms of clinical trials is required to commercialize nanotechnology-based contact lenses. This article encompasses nanotechnology-based smart contact lens technology, including materials, advancements, applications, sensor technologies, and prospects.

Abstract: Carbon nanotubes (CNTs) are a relatively new class of technical materials with a variety of unique and beneficial features. CNT is a revolutionary carrier technology for both tiny and big medicinal compounds. These formulations can be surface engineered and functionalized with predefined functional groups to control their physical and biological characteristics. CNTs have proven potential for cancer therapy along with other target-oriented therapy due to their unique features, such as ease of cell viability, high drug stacking, thermal ablation, and exceptional intrinsic physical and chemical characteristics. Graphite with Sp2 bonded carbon atoms is used for the synthesis of CNT. CNTs are fabricated in a variety of ways, including arc discharge, laser ablation, chemical vapor deposition, flame synthesis, and silane solution. The present review summarises methods of preparation, types, and various applications of CNT.

Background: Biogenic fabrication of metal oxide nanoparticles has been gaining interest over conventional methods. Biological methods make use of plant materials and microbial agents as reducing as well as capping agents. The present work reports the biosynthesis of ZnO NPs from agricultural wastes produced in every household. Objective: A significant portion of municipal solid organic waste (MSOW) consists of agricultural waste. Utilization of this agricultural waste towards cleaning water of pathogens through the synthesis of nanoparticles has far-reaching implications, such as curbing soil pollution and water pollution. Method: Preliminary confirmation was done by the visual formation of a pale yellow/dirty white precipitate of ZnO NPs. These were further characterized by different spectroscopic techniques, such as FT-IR, SEM, EDAX, and HRTEM. Results: The HRTEM study revealed that NPs obtained had sizes between 30-52 nm. Fabricated ZnO NPs were analyzed for their antibacterial activity by disk diffusion method, and they exhibited striking antibacterial activity against E. coli and bacillus subtilis. Conclusion: Exploring the potential of waste and its conversion into a value-added product is a novel step. ZnO nanoparticles were successfully synthesized from agricultural wastes through an environmentally friendly synthetic route, and the synthesized ZnO NPs were found to be potent in inhibiting the growth of bacteria.

INTRODUCTION: A chemical formula of nanocomposite 0.1 Bi2/3Cu3Ti4O12 -0.9 Bi3LaTi3O12 (BCLT-19) was prepared by semiwet route using metal nitrate and solid TiO2. The phase formation of Bi2/3Cu3Ti4O12 (BCT) and Bi3LaTi3O12 (BLT) was confirmed by X-ray diffraction (XRD) study. METHOD: Transmission electron microscope (TEM) analysis showed a nano particle of size 14 ± 5 nm on average for BCLT-19 composites. Scanning electron microscope (SEM) images exhibited a tubular, spherical and heterogeneous structure of grains. The root means square roughness, average roughness and maximum area peak height were explained by atomic force microscopy (AFM). RESULT: Study of magnetic properties was determined as weak antiferromagnetic to ferromagnetic and in nature. The high dielectric constant (ε' = 3147 at 100Hz to 500 K) of BCLT-19 may be due to the existence of space charge polarization. CONCLUSION: In this manuscript have studies on the novel composite materials of BCLT-19 micro-structural properties. This is useful for future Random-access memory devices and dielectric materials

Background: When halide salts and hydrogen bond donors are combined, they produce Deep Eutectic Solvents, which have a lower freezing/melting point than the individual components. At room temperature, they have emerged as viable alternatives to ionic liquids. The wonderful features of deep eutectic solvents such as humidity tolerance, high-temperature stability, low cost, non-hazardous, reusable, and recyclable nature, allow them to replace ionic liquids. Objective: To prepare two newer Ternary Deep Eutectic Solvents using Malonic acid - Glucose – Glutamine and Malonic acid - Fructose – Glutamine. Using the prepared ternary deep eutectic solvents, to synthesize silver nanoparticles and study the antifungal behavior. Methods: The ternary deep eutectic solvents were prepared by the evaporation method in water and subjected to measure the properties such as density, pH, conductivity, viscosity, and absorption frequencies of Fourier Transform Infrared Spectroscopy. The prepared deep eutectic solvents are used for the synthesis of Silver Nanoparticles by the chemical reduction method in presence of Hydrazine Hydrate as a reducing agent and sodium hydroxide as a stabilizing agent. The synthesized nanoparticles are characterized by UV-Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis techniques. Results: The characteristic absorption peak of UV-Visible Spectroscopy shows that silver nanoparticles were formed. FTIR exposes the metallic and other bonding of the nanoparticles and the caping materials. From the XRD pattern, we found the crystalline and the images formed in the SEM are in the nanoscale. The average particle size of silver nanoparticles is 116.87nm and 26.61 nm. Conclusion: In our study, two types of novel ternary deep eutectic solvents were developed. They act as a better solvent media for the synthesis of silver nanoparticles and the synthesized nanoparticles show antifungal behaviors against some fungi.

Background: Letrozole (LTZ), is an aromatase inhibitor used for the treatment of hormonally positive breast cancer in postmenopausal women. Letrozole is categorized as a BCS class I drug. It has poor water solubility, rapid metabolism and a range of side effects. Objective: Nanosuspension is a technique which enhances the drug's solubility and bioavailability, resulting in a faster start of effect. The present study was aimed, to formulate nanosuspension using probe sonication method for the enhancement of solubility of Letrozole using poloxamer-188 as stabilizer. The formulation scheme was generated by using Box-Behnken design which is a statistical tool of design of experiments (DOE). Results: Total seventeen formulations were performed for letrozole nanosuspension as suggested by Box-Behnken design by employing probe sonication method. The selected formulations are characterized for particle size and zeta potential. The formulations were checked on percentage of bias in between predicted value and observed value and evaluated for drug content and invitro dissolution study. The formulation was optimized using Box-Behnken design based on invitro cumulative drug release. Among all the formulations NS4 (500mg poloxamer-188, 100mg Letrozole and sonication time of 20mints) was considered to be best with minimum Particle size of 923.5nm, Zeta potential value of -28.7mV, 96.36% of drug content and 94.02% of drug release within 2 hours. Solubility was determined by shake flask method. The solubility of pure drug was found to be only 10%. The solubility studies were performed for the optimized formulation of NS4 showed that the solubility has enhanced up to 90% when compared to pure drug. Conclusion: Thus, the present results revealed that Letrozole nanosuspension solubility has enhanced up to 90% when compared to pure drug by using poloxamer-188 as stabilizer.

Abstract: This review describes the basic and application aspects of the optical properties of nanoparticles (NPs), which determine the dynamics and results of optical (laser) radiation interaction with NPs and their surroundings through NP light absorption and heat generation. In addition to the importance of primary optical processes, the thermal application of the light–NP interaction has attracted significant interest from various areas ranging from photochemistry to laser material processing and nanobiomedicine. First of all, the information provided is intended for laser specialists, photochemists and nanobiologists who are not so familiar with various optical data for understanding of the influence of NP optical properties on the results of optical or laser action on NPs and medium. Secondly, our review will be useful for researchers who conduct high-temperature investigations of the intense optical action on NPs that needs to take into account the dependence of NP optical properties on its temperature under NP heating. Our attention is focused on two variants of the applications of NP optical properties. Firstly, we shortly reviewed the optical properties of NPs at their initial or slightly higher temperatures reached under the influence of moderate radiation intensity. They are presented in numerous publications and are used as basic data. On the other side, the development of modern high-temperature laser and optical technologies needs to use the NPs optical properties at temperatures of about 1x103 K and more. For high power laser and optical technologies, it is necessary to take into account the temperature dependences of the optical parameters of various metals, dielectrics and other materials. Among these technologies, one should list laser processing of NPs, thermal laser biomedicine, solar and photo nanocatalysis, solar nanostructured absorbers. The selection and use of suitable optical properties of NPs are crucial to successful achievements and results in high-temperature experiments and applications. Novel information on optical property dependence on temperature obtained from currently available literature has been presented for possible applications in optical and laser high-temperature processes interactions with NPs. However, unfortunately, the essential information on the effect of temperature on the optical properties of NPs is currently limited. In addition to the latest information, this review also includes the figures obtained by our own calculations to provide readers with a better understanding of the NP optical properties. From the side of the application, the use of NP optical properties is considered, which provide multiple varieties of moderate and high-temperature technology opportunities, many of which are ongoing and some of them are promising bright results in the near future. The beneficial outcome and the results of further activities in the research of intense laser and optical interactions with NPs can influence various fields of science and technology: nano and photochemistry, biomedicine, nanophysics, material science, etc.

Abstract: Green synthesis of nanoparticles is an emerging topic with many significant applications in environmental and biomedical fields. The main aim of green synthesis is the development of eco-friendly nanoparticles using biological materials like plants and microbes and thus, reducing the practice of utilizing toxic substances. Different plant-derived materials are regularly utilized to synthesise sustainable nanoparticles with almost comparable properties yet utilize less hazardous manufacturing processes. This review aims to update these green synthetic processes for developing nanoparticles.

Abstract: Graphene, a layered allotropic form of graphitic carbon, has fascinated the scientific world since its discovery. Its unique structural, physical, chemical, mechanical, and electrical properties find application in many areas. Because of its large surface area and its apt electrical property, it is used in electromagnetic interference shielding. With excellent carrier mobility, it is used for sensing purposes. Mechanical strength and elastic properties coupled with its lightweight make graphene a promising material as a supercapacitor. The 2-dimensional structural properties of the graphene layers can be used for the purification treatment of water and gas. The number of research in graphene applications is increasing every day, showing the importance and excellency of graphene properties. This short review provides a comprehensive understanding of graphene's properties and progress in electromagnetic interference shielding, sensors, water treatment, energy production, storage, and conversion applications such as supercapacitors, fuel cells, solar cells and electrocatalysts.

Abstract: Lipid nanocarriers are reaching new heights in the field of drug delivery. The core of this technology resides in simple molecules, i.e., lipids. Solid and liquid lipids of biocompatible and generally recognized as safe (GRAS) status are employed for the development of lipid nanoparticles along with surfactant(s), solvents, and drug molecules. Researchers have practiced a variety of solid and liquid lipids with acceptable profiles in the formulation of lipid nanoparticles. Solid lipids like triglycerides, fatty acids, fatty alcohols, waxes, and butter have been used in designing lipid nanocarriers. The potential of various plant-based oils has also been tested in designing nanostructured lipid carriers (NLC). With the exponential advancement in lipid-based delivery systems, there exists a need for an appropriate lipid system to obtain an effective product. This review gives a brief insight into lipids, which have been exploited by researchers for designing solid lipid nanoparticles (SLN) and nanostructured lipid carriers. A tabular presentation of important key points of past studies exploiting these lipids for preparing SLN/NLC is the highlight of the article.

Introduction: Zinc oxide nanoparticles belong to the new age of nanomaterials; they are being used tremendously for the advancements of biomedicine and modern therapeutic interventions. Purpose: The current antimicrobial treatment methods fail on various levels. Thus, the recent study is dedicated to synthesizing stable zinc oxide nanoparticles. Therefore, the application of zinc oxide nanoparticles as an alternative treatment option is explored. Methods: In the current research, fabrication of zinc oxide nanoparticles is carried out via the wet chemical method. To further confirm the purity and stability of the synthesized material, characterization was performed via zeta potential analysis, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy and scanning electron microscopy. Result: SEM and TEM revealed the spherical structure of zinc oxide nanoparticles, also having slight agglomeration at a few points. The thermal stability was tested via thermogravimetric analysis and differential Scanning Calorimetry depicting the strength of the nanomaterial at a very high temperature. Elemental composition was evaluated using Energy Dispersive X-ray Spectroscopy showing 96.01% zinc and 3.99% oxygen, demonstrating the purity of the synthesized zinc oxide nanoparticles. It confirms that no other elements are present apart from zinc and oxygen. Conclusion: Zinc oxide nanoparticles were synthesized via a wet chemical method using zinc nitrate and sodium hydroxide. This fabrication procedure is reliable, cheap, and yields the most stable byproducts. Characterization was carried out via several analytical techniques to check the authenticity of the synthesized nanomaterial, thus revealing that the obtained ZnO nanoparticles could be used in medical interventions as a safe option.

Abstract: In recent years, the green synthesis of different metal nanoparticles has become a substantial technique for the synthesis of different essential nanoparticles and their potential applications in technological, industrial along with biomedical fields. Among the several essential nanoparticles, copper nanoparticles (CuNPs) have attracted enormous attention for their wide range of applications like the production of gas sensors, solar cells, high-temperature superconductors as well as drug delivery materials and catalysis owing to its distinctive optical, electrical, dielectric, imaging and catalytic, etc. properties. Herein, in this review, our aim is to find out the recent progress of synthesis, as well as different optical and structural characterizations of green, synthesized CuNPs along with their broadspectrum biomedical applications, mainly antibacterial, antifungal, antiviral and anticancer as well as the future perspective of research trends in the green synthesis of CuNPs. CuNPs have been synthesized by different researchers using three methods, namely, physical, chemical, and biological. In this review, the eco-friendly, efficient and low cost different established biological/green synthesis methods of CuNPs using different plant extracts like leaves, flowers, fruits, seeds, latex, etc., as capping and reducing agents have been briefly discussed, along with reaction conditions together with their optical as well as structural analysis. Effects of different parameters on the green synthesis of CuNPs like the presence of phytochemicals and confirmation of phytochemicals, temperature, pH, etc., are elucidated. Studies of the antibacterial activity of biomolecules capped CuNPs by different researchers against both Gram-positive and Gram-negative bacterial strains along with minimum inhibitory concentration (MIC) values have been summarized. Furthermore, antifungal and antiviral effects of green synthesized CuNPs studied by different researchers are mentioned with minimum inhibitory concentration (MIC) values. The anticancer activity of green synthesized CuNPs against different cancer cells studied by different researchers is summarized with correlation sizes of CuNPs on anticancer activity. The review also focuses on in vivo applications of green synthesized CuNPs along with clinical trails. Furthermore, an emphasis is given to the effectiveness of CuNPs in combating COVID-19.

Aims: The aim of this study is to evaluate the photocatalytic degradation of methylene blue dye on cuprous oxide/graphene nanocomposite. Background: Cuprous oxide (Cu2O) nanoparticles are among the metal oxides that demonstrated photocatalytic activity. However, the stability of Cu2O nanoparticles due to the fast recombination rate of electron/hole pairs remains a significant challenge in their photocatalytic applications. This in turn, leads to mismatching of the effective bandgap separation, tending to reduce the photocatalytic activity of the desired organic waste (MB). To overcome these limitations, graphene has been added to make nanocomposites with cuprous oxides. Objective: In this study, Cu2O/graphene nanocomposite was synthesized and evaluated for its photocatalytic performance of Methylene Blue (MB) dye degradation. Method: Cu2O/graphene nanocomposites were synthesized from graphite powder and copper nitrate using facile sol-gel method. Batch experiments have been conducted to assess the applications of the nanocomposites for MB degradation. Parameters such as contact time, catalyst dosage, and pH of the solution were optimized for maximum MB degradation. The prepared nanocomposites were characterized by using UV-Vis, FTIR, XRD, and SEM. The photocatalytic performance of Cu2O/graphene nanocomposites was compared against Cu2O nanoparticles for cationic MB dye degradation. Results: Cu2O/graphene nanocomposite exhibits higher photocatalytic activity for MB degradation (with a degradation efficiency of 94%) than pure Cu2O nanoparticle (67%). This has been accomplished after 180 min of irradiation under visible light. The kinetics of MB degradation by Cu2O/graphene composites can be demonstrated by the second-order kinetic model. The synthesized nanocomposite can be used for more than three cycles of phtocatalytic MB degradation. Conclusion: This work indicated new insights into Cu2O/graphene nanocomposite as highperformance in photocatalysis to degrade MB, playing a great role in environmental protection in relation to MB dye.

BACKGROUND: We have study the Coulomb drag phenomena for hole-hole static potentials theoretically and measured numerically using the random phase approximation (RPA) method OBJECTIVE: The drag resistivity is evaluated at low temperature, large interlayer separation limit and weakly screening regime, with the geometry of two atomically thin materials, such as, BLG/GaAs based multilayer system, is a promising systems in nanomaterials and technology METHOD: Static local field corrections (LFC) are considered to take into account the Exchange-correlations (XC) and mutual interaction effects with varying concentrations of active and passive layer RESULT: It is found that the drag resistivity is found enhanced on using the LFC effects and increases on increasing the effective mass. In Fermi-Liquid regime, drag resistivity is directly proportional to T^2, n^(-3), d^(-4) and ϵ^2 with respect to temperature (T), density (n), interlayer separation (d~nm) and dielectric constant (ϵ_2), respectively. CONCLUSION: Dependency of drag resistivity is measured and compared to 2D e-e and e-h coupled-layer systems with and without the effect of non-homogeneous dielectric medium.

Aims: The aim of this study was to evaluate the mechanical properties of polymer nanocomposites (PNCs) reinforced with multiwalled carbon nanotubes (MWCNT). Methods: Mixing MWCNT into the polymer at very small propositions can enrich the mechanical properties of the polymer nanocomposites. Testing Specimen fabricated with 0.1wt%, 0.5wt%, 1wt% mixing ratios using extrusion and injection molding process. Computational analysis was performed through the square RVE model and analyzed with finite element analysis (FEA) using DIGIMAT simulation tool. The specimen was evaluated by ASTM D3039 for tensile strength and ASTM D7264 for flexural. Results: The simulated results were compared with experimental results. Scanning electron microscopy(SEM) was performed to evaluate the dispersion state of nanotubes in the matrix. Conclusion: The impactful improvement in mechanical properties is shown in the results after addition of functionalized MWCNTs (f-MWCNT) compared to pure polymer and non- functionalized MWCNT composites.

AIM: The aim of this study was to develop and characterize Methotrexate loaded solid lipid nanoparticles by Microemulsion technique. Background: Methotrexate is a preferable anti metabolite drug. It is used in the treatment of certain cancers like breast cancer, skin and lung cancer. Clinical studies have revealed that the curative effect of MTX tablet on cancers was limited due to their toxic dose-related side effects to normal cells, nephrotoxicity, and bone marrow suppression, acute and chronic hepatotoxicity and also due to the drug resistance of the tumour cells. Hence, there is a need to develop methotrexate solid lipid nanoparticles in order to minimize the adverse effects associated with the MTX tablet dosage form. Objective: The objective of the research work is to formulate, characterize and evaluate Methotrexate solid lipid nanoparticles by micro emulsification solidification technique. Methods: Solid lipid nanoparticles are prepared by using lipids stearic acid and glycerol monostearate by varying the concentration of surfactant. Three formulations were prepared with each lipid. Micro emulsion technique was adopted for the preparation of solid lipid nanoparticles. Each formulation was evaluated for drug content, entrapment efficiency, loading capacity& invitro drug release studies. Both the lipids were compared for the characterization and evaluation parameters. Result: On comparison Glycerol monostearate was found to be a better lipid over Stearic acid for the preparation of Methotrexate solid lipid nanoparticles because of its smaller mean particle diameter (238.8 nm), higher stability (-56.5 mV) and greater entrapment efficiency. Conclusion: Methotrexate solid lipid nanoparticles were successfully prepared with higher stability and drug release rate.