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In this paper, a computational method to predict the corrosion resistance of some ironbased powder metallurgy (P/M) materials is proposed. The samples prepared from atomized iron powder and pre-alloyed iron base powders powders were the materials analyzed in this paper. The compacted samples were obtained by powder metallurgy process, respectively pressing and sintering of the mixed powders. The samples were compacted at a pressures of 400 and 600 MPa. The sintering temperature was approximately 1.150 В°C. The inf...

SF6 insulating installations are today the most performing technical solution applied to high voltage devices such as circuit-breakers and surge arresters. This gas is used due to a lot of excellent insulating properties. These properties are depending on many variables, one of them is electrodes? geometry and material. Generally, when studding the dielectric breakthrough process, ideal electrode surfaces are taken in consideration. But many experimental results, different than theoretical ones, could be a consequ...

In this paper, a pipeline implementing a multi-scale approach that can be used for modelling different steps of aerogel production is presented. Closely integrated modules for aerogel structures generation, properties prediction and adsorption, diffusion and chromatography processes modelling provide various options for systematic and comprehensive study of aerogels by performing computational experiments, which allows to reduce number of laboratory experiments. The results of pipeline validation are presented for...

In all industrial branches, the last period is under the sign of economic progress, but with the lowest energy consumption and the lowest possible release of pollutants. Technologically, therefore, the removal of polluting technologies and the introduction of new "environmentally friendly" technologies are being sought. Thus, the new industrial trend is to reduce the use of molded or forged semi finished products and the introduction of cold rolled semi finished products or other processes. This transformation can...

This paper describes the design of a new product, conceived by the authors, part of a research contract and of a technological transfer, from university to the industrial market. It is a low voltage class C surge-arrester, based only on metal-oxide varistors, designed for low voltage residential equipment. Located in the indoor interior connection boxes, it could protect the whole installation against any type of occurring overvoltage (pulsed or long time one). The results of the applicative research were transfer...

Nowadays, wearable devices represent an intensely-used technology, which helps us keep track of various vital parameters. It is a great development, its impact on society being described simply by the success among users. The data provided by wearable devices can be easily integrated with wireless sensor networks, leading to successful Internet-of-Things applications. The purpose of this paper is to analyze the current stage of wearable technology, as it represents fast and simple data sharing. These make it is es...

The report presents the results of experiments on corrosion resistant in amine environments. One of the methods of protection against corrosion damage of materials was the thermal spraying of the company 'MetallSpray'. In order to evaluate the effectiveness of the protective properties of the 'MetallSpray' spraying, it has been decided to test for corrosion / erosion resistance with corrosion sputtering coupons. On the surface of the corrosion-proof coupon D888 with the MetallSpray spraying, made using the 2017 te...

The purpose of the paper is to obtain a new composite material based on chemically functionalized nanoparticles dispersed in plastomer matrix. The dispersion of the TiO2 hybrid nanoparticles (filler) in a plastomer matrix (polyvinyl chloride-PVC) leads to a high-performance polymeric material with multi-functional, antibacterial, and plastomer-specific processing properties. The materials are suitable for biomedical and food industry applications and will be tested in terms of long-term stability, and antimicrobia...

Neural network method is used to solve complex modeling problems such as classification, estimation and pattern recognition. There are two main categories of ANNs which can be applied whether in regression or classification: the supervised and the unsupervised. In supervised model, all the data is labeled and the network is learned to predict the output values from the input data as previous experimental. In unsupervised model, all the data is unlabeled and the network is learned to inherent structure from the inp...

Testing of synthesized magnetically separable catalyst (Pd-Fe3O4/HPS) was carried out in the selective hydrogenation of 2-methyl-3-butyn-2-ol to corresponding olefinic alcohol and also in the Suzuki cross-coupling of 4-bromoanisole and phenylboronic acid in a shaker-type glass batch reactor. In the case of selective hydrogenation, the use of Pd-Fe3O4/HPS was found to result in 94% selectivity at 95% of the substrate conversion that is typical for preliminarily reduced Pd/HPS catalysts. Regarding to the Suzuki reac...

Aqueous-dispersion acrylate compositions with different contents of silica nanoparticles (NP) were prepared, which allowed to obtain top transparent coatings with improved abrasion resistance. The nanoscale silica used in the work was obtained by a gas-phase method using high-frequency induction discharge (HFI) in the air atmosphere. The average size of silica nanoparticles measured by transmission electron microscopy (TEM) and laser scattering was 23.5 nm. TEM photos of silica nanoparticles showed that silica was...

Nowadays, protection of any sensitive electric equipment against any type of overvoltage (including lightning applied on power networks) is a big challenge for the power electronics domain. The most advanced and reliable devices used in order to perform this operation are metal oxide varistor based surge-arresters. These polycrystalline ceramic varistors are made of a mixture of different metal oxides, where the main ingredient (more than 80-90% as mass concentration) is the ZnO. The real improvements of these dev...

Autoimmune diseases affect approximately 5% of the population worldwide. Generally, these disorders induce high degree of morbidity and disability and therefore, they have a significant social and economic impact. The precise diagnosis of specific autoimmune response is necessary for adequate treatment of the patient. Accordingly, the diagnostic assays for autoimmune diseases are continuously developing and improving. Biofunctionalized nanoparticles represent a promising novel approach in this field. Our group has...

The authors used a modern quantum theory allowing to determine the energy levels of electrons in real metal. What's more, the presented model allows to define the electrons energy density and consequently use the Gibbs ensemble theory. In combination of quantum theory and Gibbs statistics, the authors obtained analytical equations for both the work function and the bulk modulus of metals. Based on the obtained equations, the work function and the bulk modulus for Ti and several other metals were calculated. It sho...

In this paper, a pipeline implementing a multi-scale approach that can be used for modelling different steps of aerogel production is presented. Closely integrated modulesfor aerogel structures generation, properties prediction and adsorption, diffusion and chromatography processes modelling provide various options for systematic and comprehensive study of aerogels by performing computational experiments, which allows to reduce number of laboratory experiments. The results of pipeline validation are presented for ...

This study has its aim to compare the performance of modern structured and unstructured catalysts in a dry reforming of methane (DRM). DRM is used to obtain a mixture of H2 and CO with almost equal fractions of both products, which is subsequently used in synthesis of some chemical valuable products. The kinetic scheme for tungsten carbide (WC) catalyst was taken from the literature. Using the experimental data for a fixed bed catalyst, we have fitted the parameters of the kinetic scheme of DRM on WC catalyst. The...

Rehabilitation techniques ?weld toe grinding? and ?WIG remelting weld toe? have an beneficial influence on the increase of the fatigue life of welded structures by reducing the stress concentrators at the intersection between filler and base material. This stress concentrators reduction is achieved by increasing the radius of the connection between those two elements of the welded joint, horizontal and vertical plates. From those two techniques mentioned above, the technique that causes the greatest fatigue life i...

Variable stresses where the load value varies between a maximum and a minimum value, or varies the position in time, cause after accumulating a large number of load cycles in those structures, the fatigue failure. Fatigue is characterized by failure on values of the applied stress from the load cycles, below the material yield, values which in case of static stress would not have caused problems. Knowing that the variable stressed structures are sensitive to stress concentrators, the paper aims is to highlight the...

Due to the increased consumption of S420NL thick steel plates, the world steel price is expected to decrease. The main purpose of this investigation is to find an optimal solution both from a technical and commercial point of view to produce heavy plate 40 mm thick microalloyed S420NL hypoeutectoid steel. The imposed resistance class for this alloy is 420MPa with proven tenacity properties at temperatures up to-50 В°C. The experiment encompasses the necessity of defining a metallurgical route including chemical co...

New hybrid materials based on copper nanoparticles stabilized in an ultimately biocompatible chitosan matrix were prepared via metal vapor synthesis. Transmission electron microscopy shows that the particles have predominantly spherical form, polydisperse character, the mean diameter about 2-4 nm and a rather uniform distribution in the chitosan matrice. X-ray photoelectron spectroscopy of Cu-carrying chitosan powder obtained by impregnation of chitosan powder with Cu-acetone organosol indicated two oxidized coppe...

The use of corrosion inhibitors in the paint materials is an important task, since inhibitors often cannot be included individually in the paint formulation directly. In this case, corrosion inhibitor having a high affinity to the surface of a substrate and a plasticizing effect in relation to the film-forming base of the formed coating can have a negative impact on its adhesion and physical and mechanical properties. One of the ways to eliminate this disadvantage is the use of immobilized inhibitors, in particula...

The purpose of this paper was to develop an application to help make the decision regarding the robot model that meets the required requirements. The decision, the primary component of the decision-making system, is an essential element of management, being its specific tool of expression. In fact, the qualitative level of the leadership of an organization is manifested by the elaborated and applied decisions. In practice there are two types of decisions: the leading decision and the management decision. The decis...

Last years the use of sub- and supercritical fluids in the catalyst synthesis is a great attention. Because of the unique properties subcritical water allow synthesizing the metal-based catalysts with the desired size, dispersity, structure and morphology of the active phase. In this work, we report the study of the structure of polymer-based Pdcontaining catalysts synthesized by hydrothermal deposition. It is shown that the use of palladium chloride as a metal precursor decreases significantly the specific surfac...

Austenitic stainless steel biomedical grade type 316L, is the most used metallic biomaterials for biomedical applications due to their excellent corrosion resistance, good biocompatibility, low price, availability, easy processing and high strength. Due to these favorable combination of mechanical properties, satisfactory biocompatibility and relatively low cost, in comparison with other metallic biomaterials, 316L stainless steel has been successfully applied in medicine. In dentistry it is used in a variety of a...

Iron oxide (II, III) nanoparticles (ION) are used in variety of biomedical and industrial applications (for instance, in gene therapy, cell tracking, magnetic resonance imaging, drug delivery therapies, in vitro diagnostic assays, catalytic materials, wastewater treatment adsorbents, nanoadjuvants for vaccine and antibody production, coatings, gas sensors, ion exchangers, magnetic recording devices, magnetic data storage devices). In relation to their vast utilization there is a need for more information on the ef...

Gallium phosphide is a semiconductor material of great interest for new LED technologies. Porous AIII?V are of great interest because of their interesting optical properties different of those for bulk material. The main goal of this research work is to obtain nanostructured porous gallium phosphide (por-GaP) layers by electrochemical etching of the monocrystalline (100) p-type GaP substrate surface. The structure and surface morphology of obtained samples were studied by scanning electron microscopy (SEM), atomic...

Electrochemical method for the preparation of high-quality nanostructured surfaces and functionalization through active biomolecules electrodepositions are highlighted in this work. There are two applied electrochemical methods in order to obtain hybrid and nanocomposite structured layers or advanced functionalization of material surfaces: (i) electrochemical oxidation or anodization of materials resulting nanoporous or nanostructured oxide films and (ii) direct electrochemical synthesis by electrocodeposition pro...

The paper considers the features of the sedimentation of the lakes of the Southern Urals, Bolshoi Kisegach and Turgoyak. Previous studies shows that micrometeorites and cosmic dust can be found in different types of sediments and rocks and also magnetic properties can be used for choosing reliable samples for further investigations. Morphology and elemental composition of 5 magnetic separates studied using scanning electron microscopy in the Interdisciplinary Center for Analytical Microscopy of the KFU on the fiel...

This article was published within the Sub-project "Manufacturing of composite materials sanitary ware", funded under the "Fostering Productive Innovation" Project, supported by the World Bank and the Government of the Republic of Kazakhstan. Conservation and protection of the environment is one of the important and priority areas of the World Bank work. The Bank requires environmental assessment for the Sub-project to help to ensure its environmental safety and sustainability. Therefore, the Environmental Manageme...

The goal of the work reported in this paper is to describe and develop an artificial neural network (ANN) to evaluate the effect of processing parameters such as density, pressing and sintering time on microstructural characteristics including porosity and microstructure of some iron-based powder metallurgy (PM) materials. There are various methods for generating models to predict the the effect of processing parameters. The materials used in this study are prealloyed iron-based powders. The particle size of the p...

Skin cancer is a disease with an increasing incidence due to its complex etiology and various forms of manifestation. The topical treatment can be a successful therapeutic approach in early diagnosed cutaneous neoplasm. The main drawback of the drugs currently in use is the low bioavailability caused by many pathophysiological and pharmaceutical factors. The aim of the present study was to develop new modifiedrelease topical products by encapsulating bexarotene into biocompatible silica matrices and by formulating...

The combination of polyester polyhydroxybutyrate with polysaccharide chitosan allow to increase the terms of biodegradation and improve the mechanical characteristics of biomaterial. The investigation of compatibility of the polymers in the composition demonstrates that the content of polyhydroxybutyrate in the composition should not exceed 60% weight. Also the increase in content polyhydroxybutyrate reduces the mechanical properties of the composition. To provide the porosity of biomaterial crosslinking agent can...

This study describes the amino-functionalization of the MCM-41 mesoporous matrix by post-synthesis grafting using 3-aminopropyltriethoxysilane (APTES) and the characterization of amino-functionalized mesoporous silica MCM-41 loaded with magnolol (MGN) in order to achieve modified drug delivery systems. The aminofunctionalization of silica MCM-41 with three different levels in the number of the amino groups introduced was carried out by grafting in a field of ultrasound. MCM-41 shows a one-dimensional system of the...

Recent developments in the existing molecular genetic tools have augmented our current understanding towards the deleterious effects of nanoparticles on human health. During building construction, the rapid generation of nanoparticles has greatly affected to human with severe toxicity by generating free radicals inside their body as potential health hazards. However, there is still need of analyzing nanoparticle toxicity based on the type of microbial diversity present on surface and its potential impacts on human...

In the present study, an image porcessing analysis of porosity in some iron-based powder materials was proposed. The specimens analyzed were produced from atomised iron powders of different sizes (< 45, 45-63, 63-100, 100-150, >150 ?m). The analyzed powders were compressed in a mold using uniaxial pressing and the applied pressure was 600 MPa with the disc dimensions of ? 8 ? 6 mm. The compacts were sintered at a temperature of 1.150 В°C with the sintering time of 60 and 90 minutes. The sintered specimens obtained...

Using of biodegradable cellulose fibers in the packaging products production reduces needs in synthetic materials for these purposes. Softwood kraft fibers are widely used for cardboard and paper products production because of their high characteristic strength and good paper-forming properties. Recycling of fibers decreases their strength. It happens partly due to the removal of xylan, which plays an important role in interfiber bonds formation in a paper sheet. A priority task is to increase the number of cycles...

The research consisted in obtaining Ni-P and Ni-P-Al2O3 coatings followed by heat treatment and characterization of heat treated and untreated layers. The layers were deposited on the steel strip, by electroless method to certain process parameters. To obtain the Ni-P-Al2O3 nanocomposite layers, 5 g/L Al2O3 particles of 20 nm were introduced into the nickel bath, and it has been worked with the same parameters as to obtain the Ni-P layer. The samples were heat treated at 300 0C, 400 0C and 5000C for one hour in a ...

This work is devoted to the study and modeling of the structure and properties of silicaresorcinol-formaldehyde hybrid aerogels and of silicon-carbon aerogels obtained on their basis with pyrolysis. Experimental studies for synthesis of hybrid siliconresorcinol-formaldehyde and silicon-carbon composites derived from it were carried out. Conditions of its synthesis (the ratio of reagents, the amount of solvent, etc.) were varied. The study of characteristics includes such experiments as the measurement of thermal c...

The complex of physical-chemical investigations on study of regularities, mechanisms and peculiarities in the oxidation process of an alloy 06XN28MDT has been carried out. As a result of the corrosion tests the corrosion losses of Cr, Ni and Fe from surface of alloy 06XN28MDT in chloride-containing commercial waters with pH=6; 7 and concentration of chlorides 600 mg/1 have been determined. The regularities and mechanisms of corrosion dissolution of Cr, Ni and Fe from surface of alloy 06XN28MDT depending on change ...

Continuous improvement and technical sophistication of modern machinery and equipment, extreme conditions of process operations dictate strict requirements for structural materials to ensure their high strength, workability and reliability. A perspective way to improve the operational and technological properties of aluminum alloys is various external impacts on the crystallization processes. Such methods of preand crystallization treatment of molten metals will allow to get the target structure and mechanical pro...

Microstrip devices have found wide application in various fields of radio engineering. However, such devices are made on dielectric substrates from various materials - glass,mica, ceramics, etc. In the process of manufacturing microstrip devices, it is possible to use, as etching method, this removal of excess copper coating, and removal of copper coating with special equipment, for example a milling machine . As a result, at various stages of manufacturing, material waste remains in large quantities, a solution f...

Miniaturization of microwave devices, such as directional couplers, filters, switches, etc., is an important practical problem due to the trend of integration of portable and small high-frequency electronics. In this paper, we consider the technology of developing a miniature microstrip device, which can be used in small space satellites and other aircraft, for which mass and dimensions are important. Modeling was carried out in the program for electrodynamics analysis of radio electronic devices in the NIAWR Desi...

Morphological and structural characterisations were carried out on the layers of TiN lodged on the silicon substrate with orientation (100). The analysis of the crystalline structure of TiN films was performed by X-ray diffraction (XRD), using a diffractometer high resolution, using radiation Mo K? . The Atomic Force Microscopy Analysis (AFM) has followed the assessment of the influence of important parameters of the filing process (temperature, polarity of the substrate) on the surface morphology and the roughnes...

The structure and the properties of the oxide nano-composition coatings formed on titanium in the diphosphate based electrolytes by means of plasma electrolytic oxidation in the spark-discharge regime at application of interelectrode voltage 100 to 130 V have been studied. The possibility to obtain the oxide layers containing the alloying elements by the modification of the composition of electrolytes has been stated. The chemical and phase composition as well as the topography, the microstructure and the grain si...

This paper presents studies on the development of nanocomposites based on rubber and layered nanoclay such as organically modified montmorillonite. The effect of introducing nanoclay in a mixture based on ethylene-propylene-diene terpolymers filled with precipitated silica was analzyed in comparison with a mixture based on natural rubber filled with an organic filler, starch. Mixtures contain 0, 3 and 6 parts nanoclay respectively to 100 rubber parts. Mixtures were obtained in a Brabender mixer. Curing agents: di(...

A technical progress in various fields of the national economy is accompanied by escalating aggression of the environment that complicates the protection of different objects made from steel, which is the main modern constructional material. Because of the corrosion attack, 50 million tons of metal is oxidized and lost almost forever every year for a mankind. In industrialized countries, annually average losses from corrosion equal to 3 - 5% from the gross domestic product. The damage from corrosion comprises not ...

A wide range of researches demonstrated that the application of nanotechnology can improve the performance of other traditional construction materials, such as concrete, steel, glass, paint, coatings, insulating materials, et. al. Noteworthy improvements in concrete strength, durability and sustainability are being achieved with considered use of metal/metal oxide nanoparticles and engineered nanoparticles (carbon nanotubes and carbon Nano-fiber), and environment-responsive anticorrosion coatings formed using Nano...

Metal Oxide based Varistors are basically ceramics, acting as n ? semiconductors, having a poly-crystalline and dense structure. The main application of these power electronic devices is for construction of overvoltage protection equipment (for every voltage level), because of some advantages like: an increased level of non-linearity between the current and the voltage characteristic, a high energy adsorption capacity and an excellent good response time, which make them ideal for protecting other sensible electron...

This work is devoted to obtaining and characterization of wood-mineral composites based on wood debarking waste and basalt screenings, which have improved ecological,strength, sound and heat insulation properties. To achieve this goal, the following tasks were solved: the regularities of the process of spontaneous filling of the porous space of the wood matrix with mineral fine particles due to the capillary forces of plant raw materials were established; simulation models of the structure and functional propertie...

The necessity of fulfilling as many conditions as possible in the specification resulted in the creation of composite materials. This idea developed in the aerospace industry was later used successfully in all industrial branches. The two materials that have been used are chemically distinct, each of which retains its properties in the composite, but provides the assembly with different properties and characteristics. Thus, for the continuous phase, the matrix was used an aluminum alloy, and for the discontinuous ...