RESEARCH INTO DYNAMICS OF ADSORPTION OF HEAVY METALS ON ACID-ACTIVATED BENTONITE

Acid activation of bentonite clay is a common way to obtain porous adsorbents of organic and inorganic substances. Acid activation with preservation of the layered structure is the initial stage of chemical modification. Acid treatment of natural aluminosilicates is aimed at increasing their adsorption capacity and specific surface area. In industrial practice, water treatment of heavy metals is in most cases carried out bypassing the liquid through a fixed layer of backfill. Therefore, in this study, we studied the dynamics of adsorption with the definition of the main characteristics of the process: the speed of the working zone, the coefficient of protective action, the length of the working layer, the loss of protective action time, the duration of the sorption column before leakage. In addition, the establishment of the basic laws of this process can be used to determine the optimal parameters of the sorption material at a given initial characteristic — the length of the layer of the sorption column, the filtration rate. We have studied the possibilities of chemical modification of granular bentonite during acid-salt treatment. Through sorption columns with a height of 0.1; 0.2 and 0.3 m, filled with samples of modified bentonite, were passed model solutions of salts Fe2+, Mn2+, Cu2+ and Cd2+ with a concentration of cations of 0.01 g/dm3. The flow rate of the solution was 0.5; 1.0 and 1.5 m/h. Experimental data show that the optimal sorption values ​​are obtained for samples of modified bentonite: at the same height of the sorbent layer and flow rate, the duration of the layer before skipping in modified samples is 1.25—1.52 times higher than in unmodified ones. It is established that the sorption time before skipping mainly depends on the flow rate and the height of the sorbent layer. Thus, at a layer height of 0.3 m and the same rate of transmission of the solution, the sorption time is up to 3.5 times greater than at a layer height of 0.1 m for all investigated cations.

CONSTRUCTION OF ROTOR ANGLE IDENTIFIER IN VECTOR CONTROL SYSTEMS OF DOUBLE FEED MACHINES

In asynchronous electric drives with vector control on the rotor, it is necessary to calculate the value of the sine and cosine of the angle of rotation of the rotor relative to the stator to form control actions. When using angle sensors, complex structural tasks can arise — placement and reliable mounting of the sensor on the shaft and, accordingly, the task of the overall layout of the unit. For high-power machines, the tasks of developing and creating the design of the sensor itself arise. If serial rotor angular position sensors can be used, the task of placing and mounting the sensor is no less difficult. In these cases it is necessary to deduce the second end of a shaft from the case of the engine with contact rings that complicates its design. Therefore, the urgent need to create more reliable electric drives with vector control systems on the rotor is the synthesis of identifiers of the angle of rotation of the rotor. Identifiers are known whose calculation algorithms are based on determining the projections of the flow coupling vectors. In the work with the use of coordinate transducers of projections of stator or rotor current vectors and equations of electromagnetic circuits of an asynchronous machine, the synthesis and subsequent analysis of the properties of the rotor position angle identifier in vector control systems of dual power machines is performed. New equations of the identifier of flux couplings are received, its stability is investigated and on conditions of stability types of electric drives in which it is possible to apply the offered identifier are defined. The stability of the vector control system and sufficient identification accuracy when using the proposed equations and functions are confirmed by the method of mathematical modeling of the recommended electric drive systems in different operating modes.

FEATURES FORMATION ZONE OF WAVES AND BURSTS ON THE SURFACE LADLE BATH

The results studies influence physicochemical properties and thickness cover slag, formed during ladle desulfurization pig iron by blowing a mixture of lime and magnesium, features formation a breaker on the surface bath and the level of metal losses with emissions outside ladle from this zone are presented. The necessity creating conditions for ensuring height breaker, which would not exceed thickness slag layer on the surface bath, has been substantiated. Using results of the high-temperature simulation blowing the cast iron melt with a neutral gas supplied through the nozzles tips stationary and rotating submersible lances, features development of counter waves and metal splashes in the absence and during formation slag cover with thickness of 30—80 mm on the surface bath are determined. The features change in the height and area breakers are determined depending on the gas flow rate for blowing bath and thickness slag. Based on the analysis results low-temperature modeling bath blowing, scientific ideas about the combined effect of the bath blowing intensity, speed of rotation submerged lance and thickness slag layer on the diameter bubbling zone, gas saturation of the bath and features wave formation on its surface in the slag-free zone were further developed (so-called «eye»). The nature relationship between length of the gas jet from lance nozzle, diameter «eye», and geometric parameters breaker has been established. It is shown that dependence profile breaker on speed of rotation lance and thickness slag layer is nonlinear. So, blowing bath through tip of a rotating lance with one nozzle at 240 rpm. with a gas flow rate of 2.2 l/min. creates conditions for raising top breaker to a height that is 33 % higher than the current thickness slag layer and contributes to the intensification formation of waves and bursts on the surface bath. With a decrease in the gas flow rate to 1.0 l/min., Under other unchanged conditions, height breaker is already 2/3 of the height slag layer, and as thickness slag decreases proportionally decreases. The smallest, recorded in the experiments, relative height breaker was 33.3% of the slag thickness at a lance rotation speed in the range of 90—120 rpm. Mathematical models are proposed that are suitable for calculating height breakers depending on the thickness slag layer, speed of rotation lance and intensity of gas injection into the bath. Taking into account established mutually opposite effect thickness of the cover slag layer and speed of rotation submerged lance on the «eye» area and height of the breaker, it is advisable to continue search for ways to improve design tip submerged lance and slag mode of ladle desulfurization.

CALCULATION OF THE TEMPERATURES OF THE CHEMICAL REACTIONS OF THE IRON STEPPED RECOVERY FROM HEMATITE WITH CO GAS AND GASIFICATION OF SOLID CARBON ACCORDING EXISTING FORMULAS AND BY STANDARD VALUES OF ENTHALPY AND ENTROPY OF SUBSTANCES

The article presents the results of a thermodynamic assessment of the possibility of chemical reactions of the stepped recovery of iron from hematite with a recovering gas CO, as well as the Bell-Boudoir chemical reaction. It has been established that for each of the indicated chemical reactions there is a certain temperature (called by the author as "boundary temperature"), up to or above which CO gas cannot be a recovering agent for lower iron oxide from higher or the metallic iron itself from wustite, as well as gasification of solid carbon; while the recovery of Fe3O4 from Fe2O3 is theoretically possible at any temperatures above 0 ° C, the recovery of FeO from Fe3O4 and the gasification of solid carbon are theoretically possible above certain temperatures (i.e. at elevated and high temperatures), and the recovery of iron from FeO is below a certain temperature (i.e. at low temperatures). The numerical values of the boundary temperatures for the reactions of iron recovery and its lower oxides, as well as the reaction of gasification of solid carbon are given; graphical dependences of the Gibbs free energy of the indicated chemical reactions on temperature are made according to the equations available in metallurgical literary sources, and according to the expressions derived in the article by the author.

IMPROVING THE PERFORMANCE CHARACTERISTICS OF MACHINE PARTS BASED ON THE COMBINED INFLUENCE OF STRONG MAGNETIC FIELDS

Magnetic treatment is a promising method of hardening. Metal exposed to alternating magnetic fields changes the performance properties of the surface layer of a combination of magnetic and ultrasonic effects, provides a combined method of processing and strengthening surfaces of machine parts, which eliminates the main disadvantages of magnetic and electrical hardening — instability of physical and mechanical properties of this layer with detail. The purpose of the work is to investigate the possibility of improving the performance of machine parts based on the combined effect of strong magnetic fields. The study of the use of a uniform flux of magnetic fields generated by powerful permanent magnets was performed to affect the material volume of non-grinding plates of the cutting tool CNMG_120508E-M. The effect of uniform magnetic flux is initiated as a result of resonant oscillations of the sample caused by broadband exposure of equal amplitude by means of a "white noise" generator and a piezo emitter. The authors found that as a result of volumetric strengthening of non-grinding plates of carbide cutting tools, by exposure to polyfrequency oscillations in the form of a broadband frequency spectrum of equal amplitudes, a significant reduction in dimensional wear of the plates is achieved. Adding mechanical vibrations to the samples in a uniform constant magnetic field allowed to achieve volumetric hardening of the samples from 150 HB to 240 ÷ 250 HB, ie 60 ÷ 65% in 10—12 minutes, which is the hardening of the samples by 5—6% in one minute. The work on determining the relationship of changing properties with processing time, frequency range, amplitude and other modes to find the optimal values ​​of processing parameters, has great prospects for the ability to obtain a set of performance characteristics, control external and internal properties of products.

MODIFICATION OF HEAT-RESISTANT OXIDES AND CHLORIDES OF GRAIN SURFACES OF SYNTHETIC DIAMOND GRINDING POWDERS FOR APPLICATION IN GRINDING TOOLS

Further development of modern technologies of diamond processing is connected with application in the diamond tool of powders with new unique properties, special morphology of grains, with the increased chemical and thermal stability. To increase the heat resistance of diamonds, they are covered with a metal (metallization) or glass-ceramic layer, or introduced into the reaction mixture used in the synthesis of diamonds, alloying additives of certain elements. Recently, other methods of coating to increase the heat resistance of diamonds have been developed, such as: vacuum ion-plasma sputtering, epitaxial synthesis, magnetron sputtering, the method of liquid-phase deposition. The latter method is promising for modifying the grain surface of grinding powders of superhard materials by heat-resistant inorganic non-metallic coatings, as it is the most economically advantageous. Determining the features of the technology of modification by the method of liquid-phase application of heat-resistant inorganic coatings (oxides and chlorides of metals and nonmetals) on the surface of grains of grinding powders of synthetic diamond brand AC6, used for grinding tools in mechanical engineering. Modification was performed by the isothermal method of liquid-phase application of saturated solutions of both heat-resistant oxides (В2О3, Al2O3), chlorides (СаСl2, NaCl, MgCl2, FeCl3), and their mixtures (В2О3+СаСl2, В2О3+NaCl). Based on the analysis of the results of the research, it can be stated that the application of coatings of inorganic substances (some oxides and chlorides) increases the heat resistance of synthetic diamond grinding powders. Modification allows to reduce expenses of diamonds in wheels at grinding. Conditions for modification of heat-resistant oxides and chlorides, as well as their mixtures, grain surface of synthetic diamond grinding powders are determined. Modification of the surface of diamond grains with a combination of B2O3+Al2O3 is guaranteed to double the wear resistance of diamond wheels. It is established that in all cases of modification the roughness of the parameter Ra decreases. It is determined that by changing the surface modifier of diamond grains it is possible to affect the bearing capacity of the rough surface obtained by grinding. The development of effective ways to increase the heat resistance of grinding powders made of superhard materials, primarily abrasive grinding powders made of synthetic diamond powders, helps to improve the quality of the grinding tool.

INFLUENCE OF FUNCTIONAL COMPONENTS ON THE TITER OF LACTIC ACID BACTERIA OF YEAST "VIVO"

The use of yeasts with a high titer of probiotic cultures of lactic acid bacteria (LAB) and plant components, ascorbic acid in the technology of obtaining functional products - can improve the quality of finished products, nutritional and biological value. The aim of the study was to study the effect of functional components and antibiotics of different groups in the elective nutrient media "Lactobacagar" and "Bifidoagar" on the LAB titer and their viability. The task of the work is to determine the feasibility of using extracts of milk thistle, rye seeds, flax and ascorbic acid in nutrient media for the viability of LAB yeast "VIVO" with the addition of antibiotics of different groups and concentrations. The effect of the most commonly used antibiotics was studied: benzylpenicillin, azithromycin, lincomycin, gentamicin sulfate, ceftriaxone, norfloxacin, amoxil, streptomycin, tetracycline, erythromycin on the titer of lactic acid concentrations, which correspond to IV bacteria; 50; 25; 12.5; 6.25; 3.13; 1.56; 0.78. Determination of antibiotic resistance of LAB was performed by the method of double dilutions. Determination of antibiotic resistance of LAB was performed by the method of double dilutions. The effectiveness of the use of extracts of milk thistle, flax and red seed, as well as ascorbic acid in the practice of nutrient enrichment has been proven. The introduction of these components into the composition of nutrient media with antibiotics led to an increase in the number of viable LAB cells by 5—9 %. It is recommended to enrich fermented milk products and bakery products with functional components — seeds or meal of red flax, flax and thistle to increase the nutritional value and increase the titer of fermentation microflora.

SIMULATION OF AN ADARTIVE FILTER BASED ON THE RECURSIVE LEAST SQUARES METHOD

Modern electronics systems are high-speed, compact and require the use of energy-efficient digital electronics devices (DED’s) such as microcontrollers, programmable logic integrated circuits (FPGA’s), digital signal processors. Application of the DED’s is a hardware implementation of high - performance digital signal processing (DSP) algorithms based on the target architecture of the electronic device. In order to accellarate of the design process in the direct hardware implementation of DSP algorithms, simulation models are created to enable optimizing the design process at the stage of a creation of the programming part for FPGA. The paper presents the results of a study of the adaptive filter (AF) model based on the recursive least squares method (RLS). According to the analysis of time and frequency parameters of the AF model has been conducted during simulation it was found that the qualitative filtering process starting from the 24th order and further increasing the AF order does not significantly improve signal filtering, but only increases the required hardware resources. In process of the verification of the proposed simulation model, the AF-based noise reduction system has been modeled and the THD level of 7.103 % was obtained for the built-in AF unit, which is more than one and a half times higher than the proposed AF unit 4.323 %, which confirmed the efficiency of the developed AF unit. Thus, during the study, the optimal order of AF has been determined, which will allow more efficient use of FPGA resources during the hardware implementation of AF. In accordance with the results of the study, the correctness and efficiency of the created hardware-oriented simulation model has been proved, as well as the hardware-oriented structure of the adaptive RLS filter for future implementation on FPGA nas been shown.

EDUCOLOGICAL ASPECTS OF ACTUALITING OF REGULATORY DOCUMENTATION IN MECHANICAL ENGINEERING

The main competencies of specialists in the field of knowledge 13 Mechanical engineering appertain the ability to draw up technical documentation, which includes both the design of text documents and drawings of parts, units, assemblies. Over the last decade, there has been a significant update of the standards of both the Unified System of Design Documentation and the Unified System of Technological Documentation. Suitable, according to the principle of education, to ensure the quality of the educational process, the task of implementations modern regulations into the educational process and providing students with practical skills in the design of educational documentation, which is as approximate as possible to the technical future practice. The purpose of the work is to develop proposals for the implementations of relevant regulations in the regulatory and methodological documentation of the educational process to ensure that higher education students acquire practical skills in applying this knowledge in the design of educational documentation with the closest possible approximation to real technical documentation. From the analysis of the requirements of the acting standards that make up the system of design and technological documentation, it follows that their requirements are quite diverse and allow some flexibility of choice, depending on the needs of developers or consumers. Corresponding, according to the provisions of education, the current methodological and regulatory documentation of higher education institutions should provide information to students about the existing system of standards for technical documentation and their practical skills in applying such knowledge. Based on the standards of the Unified System of Technological Documentation and DSTU EN ISO 7200: 2005, proposals have been developed for the design of educational documentation by students of mechanical engineering specialties according to educational and professional programs. The proposals concern the determine of the institution of higher education as the owner of the document, the numbering of documents of the educational process, the designation of sections of the document, page numbering, design of the main inscription of drawings and the title page of text documents. In particular, a numbering system has been developed, which allows to mark the whole set of documents of the educational process of a particular applicant, individual documents by type, separate sections of text documents and drawings. A single form of the main inscription has been developed, which can be used both for text documents and for drawings. The proposed innovations relate mainly to the specialties of mechanical engineering for educational and professional programs. But they can be used, in whole or in part, for other specialties and fields of knowledge.

AUTOMATIC DESIGN FEATURES OF COMPLEX SHAPE DETAILS AND TECHNOLOGY OF THEIR MANUFACTURING

The creation of modern high-performance machines often involves design of details with complex surfacese and made with high precision. At the stage of design and preparation of production, project work is carried out using automation tools and modern information and computer technologies. The process of creating a project is accompanied by the preparation of appropriate documentation, sufficient to solve all possible questions, starting with the formation of a design task and disposal of the product at the end of its operation. According to statistics, most details in mechanical engineering are simple in shape, relatively technological in production, and their surfaces are most often described in the drawings by a set of lines and circles (radius of curvature). This approach is economically justified and will ensure the reliable operation of the product during operation. Significant difficulties arise when it is necessary to design parts with surfaces of complex geometric shape, when the geometric parameters are set by coordinate points. The accuracy of surface description depends on the number of such points and the accuracy of numerical data. Typical examples include turbine impellers, parts with aerodynamic surfaces that are used, for example, in the aerospace or rocket industries. The process of manufacturing such parts is accompanied by overcoming specific difficulties in describing complex surfaces at the stages of design and technological preparation, as well as directly in the manufacture of parts on technological equipment, intermediate and final control of geometric accuracy. An option for an effective solution of such problems is to record complex smooth surfaces, predefined by a set of coordinate points, splines. Modern design automation tools make it possible to use this mathematical method for modeling complex geometric objects and use it to calculate the trajectories of the forming tool on CNC machines. On the example of parts from production, which has a complex surface, using computer-aided design systems considered options for making design and technological design decisions for production preparation, equipment design, control the accuracy of shaping when machining on CNC machines.