The purpose of this study was to study the physical properties (particle shape, size, specific surface area, granulometric composition), as well as the elemental composition of the powder obtained by electroerosion of conductive waste of beryllium bronze BrB2 in distilled water.

Methods. Beryllium bronze waste BrB2 was processed into powders at an experimental electroerosive dispersion plant in distilled water. The tasks set in the work were solved using modern equipment and complementary methods of physical materials science, including: grain composition and average particle size (laser particle size analyzer "Analysette 22 NanoTec"); shape and morphology of the particle surface (scanning electron microscope (SEM) "Quanta 200 FEG"); chemical composition (energy dispersive X-ray analyzer of the company "EDAX", built into the SEM "Quanta 600 3D".

Results. Based on the conducted experimental studies aimed at studying the physical properties and elemental composition of the powder obtained at the experimental installation by electroerosion of beryllium bronze waste BrB2 in an aqueous medium, the high efficiency of the use of electrodispersion technology, which provides, at low energy costs, the production of a new beryllium bronze powder suitable for industrial use, is shown. The following characteristics of powder materials obtained by electrodispersing beryllium bronze waste in distilled water have been experimentally established: the shape of the powder particles is spherical and elliptical, fine particles form agglomerates; particle sizes from 0.1 to 100 microns; the volumetric average diameter of the particles is 23 microns; the specific surface area is 0.19 m²/g, the main elements are Cu, Be, Ni, Fe, Si, and Al.

Conclusion. The conducted research on the production of a new electroerosive powder of beryllium bronze BrB2 and the study of its properties will allow for a consistent transition to advanced production technologies and materials through the use of promising, harmless to humans and the environment, low-tonnage and waste-free technology of electroerosive dispersion.

The purpose of this study is to conduct X-ray spectral and X-ray diffraction analysis of the electroerosive charge from waste steel R18.

Methods. To obtain new experimental powder materials (charge) from R18 steel waste, an electroerosive dispersion unit was used. For the study, we used an electroerosive charge from waste steel P18. For X-ray spectral analysis, the method of scanning electron microscopy was used, using an energy-dispersive X-ray analyzer from EDAX, built into a scanning electron microscope "QUANTA 200 3D". X-ray diffraction analysis was performed using a Rigaku Ultima IV diffractometer.

Results. The distribution of chemical elements over the surface of the electroerosive charge from R18 steel waste was experimentally established: carbon, oxygen, molybdenum, vanadium, chromium, iron and tungsten, and the main phases of the charge obtained by electroerosion dispersion from R18 steel waste were determined: WC, Fe₂W₂C, FeV,

Fe₃O₄.

Conclusion. According to the results of the research, it can be concluded that the grinding of waste steel R18 by electroerosion in distilled water leads to the formation of a charge with an elemental and phase composition that allows it to be used as the main material for the production of new tool products, cutting plates, knife blades, and also for the restoration and hardening of tools, parts of automobiles and agricultural machinery, by surfacing, welding and related processes. The obtained results can be used for further research of the electroerosive charge from R18 steel waste.

Purpose. Study of the effect of the dispersion medium on the properties of electroerosive heat-resistant powders from waste alloy ZHSU6.

Materials and methods of research.  Grinding of metal waste of the ZhS6U alloy was carried out by electrodispersion in distilled water and kerosene lighting. To study the composition, structure and properties of the obtained metal powders, the following research equipment was used: the shape of metal powder particles was studied on a QUANTA 600 FEG microscope; the dimensional characteristics of powder particles were studied on an Analysette 22 NanoTec analyzer; X-ray spectral microanalysis of metal powder particles was carried out on an analyzer embedded in a QUANTA 200 3D microscope; X-ray diffraction analysis of metal powder particles was performed on a Rigaku Ultima IV diffractometer.

Results and discussion. The interrelations between the composition and properties of the working fluid and the granulometric, elemental, and phase compositions of electroerosive heat-resistant powders from the waste of the alloy ZHSU6 have been established, allowing to vary their properties. During the experiments, it was found that the chemical composition of the working fluid affects the elemental and phase compositions of the metal powders obtained, and the dielectric constant of the working fluid affects their dimensional characteristics. In addition, it was found that the presence of oxygen on the surface of the particles of the resulting metal chips and decarbonization of carbides until the appearance of pure metals W and Cr in them as a result of dissociation of oxides contributes to the presence of carbon in the working fluid – distilled water. In turn, the formation of carbides phases such as WC, Mo2C, TiC and Cr7C3 is facilitated by electrodispersion in the working fluid – in kerosene lighting. It is noted that the average particle size of metal chips increases with a decrease in the dielectric constant of the working medium. 

Conclusion. The conducted studies aimed at studying the influence of the working environment of electrodispersion on the properties of electroerosive heat-resistant powders from waste of the alloy ZHSU6 will solve the problem of saving expensive alloying components.

Purpose. The study of nitrocementation of steel 9XC at a temperature of 560 ° C in a highly active solid nitrogencarbon medium based on amorphous carbon and nitrogen–containing components – carbamide and potassium ferricyanide – was undertaken.

Methods. The microstructure of nitrocemented steel on transverse sections was studied using an XIMEA optical microscope with Axalit software, as well as using a Qanta FEG – 650 electron scanning microscope with a focused ion beam EBCD microanalysis system. A layer–by-layer X-ray diffraction analysis of samples on the XR-700S diffractometer in chrome radiation was carried out.

Results. The wear tests of carbonitrated specimens were carried out under friction conditions similar to those of punching tools. The wear resistance of nitrocarburized samples was studied on an SMTs-2 friction machine. The tests were carried out both under dry friction conditions and under boundary friction conditions. High efficiency of the proposed paste at this temperature was experimentally shown. As a result of nitrocementation, modified layers saturated with solid inclusions (ε-phases) are formed on the surface of steel. These modified layers are characterized by high hardness, low coefficient of friction and high wear resistance.

Conclusion. Based on the results of the studies, it can be concluded that the nitrocarburizing of die steel 9XC, carried out in a highly active nitrogen-carbon paste at a carbonitration temperature (560 ° C), contributes to the formation of modified layers saturated with carbonitrides (mainly hexagonal carbonitride ε) on the surface. The modified layers are characterized by a very low coefficient of friction and very high wear resistance. Nitrocarburized steel 9XC can be used for the manufacture of working parts of dies, instead of more expensive high-alloy steels (for example, X12), which can increase the economic efficiency of mechanical engineering.

Purpose. Optimization of the process of obtaining electrocorundum particles by electroerosive dispersion of waste electrical aluminum grade AD0E in distilled water.

Methods. Electrodispersion of aluminum waste of the AD0E brand was carried out in distilled water on an original patented installation. As a result of exposure to short-term electrical discharges, droplet-like particles of electrocorundum of various sizes were formed. At the same time, the shape of the electrocorundum particles was examined on a scanning microscope, and the average particle size was examined on a laser analyzer. 

Optimization of the production process of droplet-like particles of electrocorundum by electroerosive dispersion of electrical aluminum waste of the AD0E brand was carried out according to the average particle size, since it is one of the main technological parameters of powder materials. To optimize the process of producing electrocorundum particles by electrodispersing aluminum waste of the AD0E brand, the method of steep ascent by Box and Wilson was used.

The adequacy of the equations was checked using the Fisher Criterion. 

Results.In accordance with the goal aimed at optimizing the production process of electrocorundum particles by electroerosive dispersion of electrical aluminum waste of the AD0E brand in distilled water, it was found that the optimal average size of electrocorundum particles is 74.2 microns with a discharge capacitance of 65.5 UF, a voltage at the electrodes of 200 V and a pulse repetition frequency of 200 Hz. 

Conclusion. The high efficiency of the use of electrodispersing technology is shown, which provides, at low energy costs, the production of commercially suitable new electrocorundum powder particles with spherical and elliptical shapes. Carrying out the planned measures will solve the problem of reducing the cost of production of electrocorundum.

Purpose. Obtaining multiferroic nanofilms from stabilized magnetite and barium titanate by the Langmuir-Blodgett method, establishing the nanostructural relationship and controlling their properties under the influence of both magnetic and electric fields.

Methods. Deposition of multiferroic magnetite and barium titanate nanofilms by the Langmuir-Blodgett method, probe microscopy, FTIR spectroscopy, Raman light scattering, X-ray phase and X-ray structural analysis, piezo response microscopy and temperature dependence of magnetoresistance.

Results. А highly dispersed stabilized magnetite with a particle size of 25 nm according to atomic force microscopy data was synthesized by chemical condensation method. Stabilized magnetite nanofilms were obtained by the Langmuir-Blodgett method. Their chemical structure was confirmed by FTIR spectroscopy and Raman spectroscopy - lines corresponding to both magnetite and its stabilized shells were observed. Based on X-ray diffractometry data, the lattice period of the cubic syngony of magnetite was calculated to be 8.3566 Å. Composite layered structures made of highly homogeneous films of barium titanate and magnetite were created by the Langmuir-Blodgett method. The monodomainization effect of the investigated films with dimensions corresponding to the superparamagnetic range caused by the expected growth of saturation magnetization in the magnetite film structure as compared to the bulk material was established. The temperature dependence of magnetoresistance was investigated. The studies made it possible to confirm the occurrence of the magnetoelectric effect in these nanocomposite structures, the occurrence of which is caused by the manifestation of a complex of magnetostrictive and piezoelectric properties characteristic of the constituent phases.

Conclusion. In Langmuir-Blodgett multiferroics in the form of composite nanofilm structures of stabilized barium titanate/magnetite nanoparticles the possibility of reversible control of magnetic or electric fields on magnetostrictive and piezoelectric properties by combining both forward and reverse piezo- and magnetostrictive effects was confirmed.

The purpose of the work. Development of a method for analyzing the composition of fiberglass raw materials using nanoanalytical equipment, studying its components and comparing them with the physical and mechanical properties of finished (polymerized) products to predict product quality. Determination of the atomic and partially molecular composition of samples. Establishment of the percentage ratio of the polymer matrix and fillers. Determination of the average diameter and length of a fiberglass fiber in various samples. Comparison of the physical and mechanical properties of prototypes and the data obtained on their composition.

Methods. Measurement of the average diameter of glass fiber in various samples was carried out using a JEOL 6610LV scanning electron microscope of the Regional Nanotechnology Center of SWSU. The atomic composition of the premixes was determined on an Oxford EMF attachment for an electron microscope. An IR Fourier spectrometer was chosen to study the molecular composition. The percentage ratio of the polymer matrix and fillers was determined using thermogravimetric analysis. The measurement of the average length of a fiberglass fiber was carried out by means of image processing in the Gwyddion software environment. 

Results. With the help of nanoanalytical equipment, the parameters of IUD composite materials were obtained: the composition and percentage of the polymer matrix, as well as its fillers, the shape and size of the fillers, and the effect of the length-to-diameter ratio of a reinforcing fiber fiber on the bending strength of a plastic product was studied. 

Conclusion. A method for determining the composition of the fiberglass premix has been created, the influence of the percentage ratio of the components, the size and shape of fillers on the strength properties has been determined to check the quality of the input raw material and predict the properties of products from it. 

Purpose. Experimental study and mathematical modeling of the processes of structure formation in the accommodation zone of a system of wedge-shaped twins in commercially pure titanium.

Methods. Methods of Microindentation, chemical etching, mathematical modeling and electron probe microscopy were user.

Results. While forming of wedge twin in poly-crystal of titanium are forming conditions of formation of additional twin in its transition zone. Forming of the extra twin is some way of relaxation of high stresses in the tips. The performed mathematical modeling of the stress distribution in the region of the twinning process, taking into account the presence of the detected accumulation of formed low-angle boundaries, makes it possible to state that the interaction of structural defects with defects formed during the development of the twinning layer is regular. The proposed model indicates that the formation of low-angle boundaries due to the interaction of existing material defects and twinning dislocations leads to a change in the stress diagram in the transition area, which, in turn, generates multiple low-angle borders in the form of the dislocation walls. Shown physical mechanism and mathematic model gives rather clear picture of forming of structure and spreading stresses in zone of forming of two parallel twins.An accumulation of low-angle boundaries was found in the accommodation zone of the wedge-shaped twin, which were regularly formed during its growth.

Conclusion. In the work, we have presented the results of experimental studies and mathematical modeling for the processes of the structure formation in a transition zone of wedge-type twins system in commercially pure titanium. The process of interaction of structure defects with twinning dislocations during the formation of a wedge-type twin was taken into consideration. It is shown that the interaction alters the stress maximum in vicinity of boundaries in the system two wedge-type twins.

Purpose. To study the dynamics of magnetic fluid and bidisperse magnetic systems under oscillatory shifts.

Metods. The experiment was carried out on installations created on the basis of well-known methods and equipment for magnetic measurements and were made independently. An original method for measuring the viscoelastic parameters of magnetic fluid systems has been developed. In this work, a magnetic fluid was studied, where magnetite Fe₃O₄ was used as a base, oleic acid was used as a stabilizer, and kerosene was used as a carrier liquid. To obtain a bidisperse system, magnetite particles (particle size 300 nm) 1%, 5%, and 10% by weight of the solid phase were added to the MF-1 sample, and MF-2 - MF-4 liquids were obtained, respectively. Liquids were prepared by mechanical and ultrasonic mixing of magnetite particles with a ferrofluid. Another important characteristic of these systems is the dependence of viscosity on temperature. To obtain it, the installation was significantly modernized. A sealed liquid circuit was made around the measuring cell, connected by a system of silicone flexible tubes to a thermostat. Results. Samples with different physical parameters are considered, and the magnetoviscous effect is studied. The microstructure of the sample and the presence of large magnetic particles affect the dynamics of magnetic fluids subjected to oscillatory shear and magnetoviscous effects.

Conclusion. The dynamics of a magnetic fluid and bidisperse magnetic systems under oscillatory shifts in a strong magnetic field has been studied. The temperature dependence of the damping coefficient of the magnetic fluid is obtained. The results can be used in the development of express tests of ferrofluid samples and in the creation of acceleration and vibration sensors. The results of this study can also be used to study the agglomeration of nanoparticles.

The purpose. The experimental detection of the effect of laser scribing and magnetron sputtering on the sign of charge formation of wire electrohydrodynamic electrode pairs immersed in a PMS-50 (polymethylsiloxane liquid coolant). Objectives. Determination of laser irradiation modes leading to the most developed microstructures on the surface of copper wire electrodes. Investigation of the presence and distribution density of self-organized structures into groups of nanostructures under irradiation. Obtaining anisotropy of current-voltage characteristics for different variants of cathode-anode pairs.

Methodology. The surface of wire copper electrodes was modified by laser scribing on the FMark-20RL marking complex with a power density in a laser beam pulse of about 4,8∙109 W / cm2 (with a pulse frequency of 100 kHz, a wavelength of 1060 nm). The surface structures of electrodes after treatment with a laser beam with a diameter of ~80 μm with a propagation step of 50-80 μm and obtained additionally by magnetron sputtering on a MVU TM Magna T setup were studied by scanning electron microscopy on a JEOL 6610lv SEM. The peculiarities of charge formation from the obtained modified electrodes were investigated by the method of current-voltage characteristics (I-V) using a Keithley 6487 picoammeter and a high voltage source Mantigora NT-6000R.

Results. For cathodes made of copper wire electrodes scribbled by laser radiation and coated with magnetron sputtering, the current-voltage characteristics reveal a nonlinear growth, which is described indirectly in the high-voltage part by the field emission mechanism of electrical conductivity. Nonlinear growth starts from the initial site.

Conclusion. Electric fields localized at the tops of structures additionally arising during magnetron sputtering on micro- and nanostructures, the surface of electrodes ablated by laser radiation, leads to a predominant unipolar injection of electrons from the cathode, similar to field emission, which can be used in the development of high-performance electroconvective systems.

Purpose to investigate the possibility of assessing the quality of chilled chicken meat by simple methods to identify violations of storage conditions. Assessment of the possibility of replacing the cooling process (temperature from - 0  to 4°C), during which the color, taste, smell, juiciness are preserved, but the shelf life is reduced, by freezing (temperature regime from -12 to – 18°C), accompanied by loss of meat taste, odor change, deterioration of the structure. Methods: analytical electrochemical methods for measuring the pH and electrical conductivity of an aqueous extract of meat in combination with organoleptic control and evaluation of appearance.

Results. The effect of the duration of the chilled meat in unfavorable storage conditions (261С) on the pH and electrical conductivity of its aqueous extract is investigated. It was found that a slight violation of storage conditions and the presence of chicken meat in such conditions does not affect the pH value, its value remains in the range characteristic of high-quality meat. The output of the specified range of pH values is observed only after a day of meat at elevated temperatures. 

In the paper the possibility of using analytical electrochemical methods to identify the replacement of meat cooling by freezing, carried out in order to increase the shelf life of chilled meat is evaluated.

Conclusion. The conducted studies have shown that in order to determine violations of the storage conditions of chilled chicken meat for three hours at room temperature, the use of pH measurement of the extract and its electrical conductivity is not effective, due to the processes of initial rotting and sliming in the same range of pH and electrical conductivity. In general, it is ineffective to use the selected electrochemical methods of analysis to control violations of storage conditions without organoleptic control.

Purpose. The aim of the work was to assess the possibility to use a folic acid drug as a standard sample and to choose the conditions of determination of folic acid by spectrophotometric, fluorimetric and chromatographic methods of analysis with the best metrological parameters.

Methods. For spectrophotometric measurements we used a two-beam scanning spectrophotometer UV-1800 Shimadzu (Japan), for evaluation of fluorescence - liquid analyzer "Fluorat-02-Panorama" (Russia), For chromatographic studies - liquid chromatograph LC-20AD from Shimadzu (Japan), equipped with a spectrophotometric detector SPDM20A and a column Nucleosil C18 (octadecyl), size 25 x 4,6 mm, firm Supelcosil. The method of spectrophotometric determination of folic acid is based on the reaction of obtaining an azo dye with a steady violet color, the intensity of which is proportional to the content of the analyte. The fluorimetric determination of folic acid is based on the oxidation of the analyte with potassium permanganate, which produces reaction products with fluorescence. Chromatographic analysis is based on a directly proportional relationship between peak area and folic acid concentration.

Results. In this work we studied the influence of the nature and pH of four buffer solutions on the degree of extraction of folic acid from dosage forms. The most complete extraction of the analyte (R = 96.83%) was detected in case of using phosphate buffer solution with pH 6.8. A fluorimetric method of determination of folic acid with higher sensitivity as compared to the state methods was proposed, the detection limit was 0.02 µg/ml. Due to a break in the concentration range of the analyte, the sensitivity of the colorimetric method was increased, the detection limit was reduced to  0.13 µg/ml. A chromatographic method of folic acid determination with a linear range of 0.1 - 10 µg/ml, and a detection limit of 0.1 µg/ml were developed.

Conclusion. The proposed methods for determining folic acid have been validated in the analysis of samples of cow's milk and white beans. The use of Fisher's test and a modified Student's test showed the absence of systematic error.

Purpose of research. The purpose of this work was to study the sorption process of direct dyes with sawdust depending on the pH of the medium.

Methods. Waste from the woodworking industry was used as a sorbent – birch sawdust with a particle size of less than 2 mm. Two direct light-resistant dyes were selected as adsorbates by preliminary tests: turquoise CB, red 2C. 

3D models of the structure of these direct dyes, constructed using ChemOffice, are presented.

Results. The light absorption maxima for direct light-resistant dyes were selected: red 2C - 520 nm, and turquoise CB - 610 nm. The article studies the effect of sawdust mass on the degree of sorption of direct light-strong dyes (turquoise CB and red 2C) from aqueous solutions.

The regularities of the kinetics of sorption from aqueous solutions of direct light-resistant dyes with birch sawdust depending on the pH of the medium are investigated. Kinetic curves of the sorption process of direct dyes with sawdust are analyzed.  The presentation of experimental data as a dependence of the degree of achieving the equilibrium of sorption (F) on time (t) allowed us to determine the criteria for the stage limiting the rate of absorption of the substance. In order to confirm the influence of external and intradiffusion processes on the sorption rate, the corresponding processing of kinetic curves in the corresponding coordinates -ln(1-F) from t and G_t from t^0.5 was carried out.

Kinetic values of approximation reliability are obtained.

Conclusion. The results obtained showed that, depending on the pH of the medium, sawdust has the best sorption properties in relation to the direct turquoise dye in an acidic medium, and is practically not sorbed in a neutral medium. The effect of the pH of the medium on the sorption process of the direct light-strong red dye has a less pronounced character: the degree of sorption does not exceed 50% for almost the entire period of phase contact. It is proved that birch sawdust can be used for wastewater treatment from direct light-resistant dyes.