Quantum chemical calculations of the heats of reduction with carbon monoxide of the simplest electrically neutral or electrically charged oxides and oxides of nickel Ni2O2 and Ni2O, as well as of copper oxides and oxides of Cu2O2 and Cu2O, are performed. The heats of transformation of neutral or charged oxides and oxides of copper into active isomers with an O-radical are also calculated. Based on the calculation results, an explanation is proposed for the experimental results on the change in the rate of reduction of oxidized nickel and copper nanoparticles by carbon monoxide when an electric voltage is applied to them.

Gold, nickel and platinum nanoparticles (NPs) have been synthesized by impregnating single-crystalline silicon surface with precursors (aqueous solutions of corresponding salts). The morphologies of the formed nanostructured coatings have been studied, and the electronic structures of the synthesized NPs, as well as their adsorption properties with respect to H2, O2, and H2O, have been determined. It has been found that oxidized nickel NPs are reduced by molecular hydrogen, while pure platinum NPs are oxidized by molecular oxygen already at room temperature. This phenomenon has not been observed for particles deposited in a similar way onto highly oriented pyrolytic graphite. In addition, it has been revealed that water molecules are formed on gold NPs as a result of the interaction between H2 and O2 in two stages, in contrast to the three-stage process (sequential exposure in H2, O2, and H2), which is inherent in NPs deposited onto graphite. Differences in the adsorption properties of NPs of the same type deposited onto graphite and silicon are associated with the adsorption of a significant amount of the test gases on the latter.

The issue of improving the production efficiency and competitiveness of high-carbon steel wire, determined by a rational ratio of quality and costs of its production, is an urgent task. The main way to solve it is the development and implementation of an effective technical process, the main elements of which are the technological process and equipment for its realization. Since the middle of the last century, domestic steel wire production has been operating on imported equipment, which significantly hampers the use of modern technological processes. This unfavorable situation has been aggravated at present by the imposition of severe economic sanctions by “unfriendly states”. The way out of this situation in the current production is the improvement of existing and introduction of new methods of wire drawing. According to the original methodology the analysis of the existing at one of the domestic enterprises route of drawing of high-carbon wire rope wire with a diameter of 1.70 mm from wire rod of 5.50 mm with the use of standard single monolithic fibers, twin monolithic fibers, roller fibers, as well as modules including roller and monolithic fibers (combined drawing) was carried out. The obtained results have shown that when using standard fibers, the drawing route should be designed with the minimum possible multiplicity, which will provide on the existing equipment to improve the quality of wire and reduce the cost of its production. The greatest efficiency is provided by the application of combined drawing: twofold reduction of drawing multiplicity, energy saving up to 30%, improvement of wire quality by creating a favorable stress-strain state when deforming the wire first in roller and then in monolithic drawing. In addition, in comparison with the roller fibers, the equipment is simplified and the costs of its purchase and operation are reduced. Recommendations on the directions of increasing the efficiency of production in the conditions of existing production, purchase of new imported and designing of domestic drawing equipment are given

Reinforcing wire is the main structural element in reinforced concrete structures, widely used in the construction of buildings and structures for various purposes. The type of profile is important factor which determines the consumer properties of fittings. This indicator directly affects the quality of reinforcement adhesion to concrete and the properties of the wire. Currently a periodic profile is the most common type, but a screw profile is the most promising form of the profile. Two methods are used in the production of cold-formed screw profiles: applying a screw profile and torsion process. The first is carried out by rotating the profiling element, and the second by torsion of the workpiece of the shaped section. The patent and literature review of methods for obtaining cold-formed screw profiles has shown that the most effective way to obtain reinforcing wire with a screw profile is torsion, which provides, in addition to profiling, an increase in the mechanical and operational properties of the wire. With the help of the Deform-3D software package we identified impact of the profile, namely the shape of the cross section on the tension. By choosing rational torsion parameters, it is possible to achieve a favorable stress-strain state and respectively the properties of the product. One of the promising areas of development is the combination of a periodic and a screw profile, and it is necessary to obtain a screw profile using torsion deformation as a method of intense plastic deformation in order to form a uniform structure in metal with a minimum stress state in addition to the profile. We justified the application of radial shear broaching, an analogue of the radial shear rolling process, which allows to obtain a screw profile reinforcing wire with high mechanical properties due to the production of a finely dispersed structure. This method is implemented on standard drawing equipment and provides an increase in the productivity of wire production by torsion compared to other methods

The main building material at present is concrete, strengthened by reinforcing elements of various configurations and methods of application. The most effective type of reinforcement for prestressed reinforced concrete structures is a reinforcing rope, which is reinforced in two ways: “on stop” and “on concrete”. The most important requirements for reinforcing ropes are high strength and adhesion to concrete when reinforcing “on the stop”, and a smooth surface when reinforcing “on concrete”. In the current practice of production and use of reinforcing ropes, round tempered or stabilized seven-wire ropes are most widely used. However, these ropes have a relatively low adhesion to concrete, which does not allow a higher prestress to be transferred to the concrete. The aim of the work is to determine the direction of development of production and application of reinforcing ropes based on the analysis of their structures. The analysis reveals the adhesion to concrete is determined by the design of the rope. In addition, the complexity of the manufacturing process, production costs and operating conditions depend on the design. The resistance to rope move-ment in concrete is determined by mechanical and “corkscrew” coupling, with mechanical coupling being the most ef-fective. An increase in the adhesion of the ropes was achieved by the developed surface, shaped section, and lay of wires with a periodic profile. However, these methods complicate the design, manufacturing technology and operating conditions of the rope. The most effective way to increase the adhesion of a reinforcing rope to concrete is the calibrat-ing compression of a twisted rope in a roller die with simultaneous application of a profile to the outer surfaces of the wires of the upper layer. This provides, without changing the design of the rope and the technology of its manufacture, a significant increase in the adhesion of the rope to concrete, its quality indicators and operational properties. In addition, the use of calibrating compression in a round gauge provides an increase in efficiency of reinforcing ropes for reinforcement “on concrete”.

— A nanostructured gold–nickel coating has been synthesized on the surface of pyrolytic graphite. Its physicochemical properties have been studied by scanning tunneling microscopy and spectroscopy, Auger spectroscopy, mass spectrometry, and other methods. It has been found that the coating consists of clusters formed by gold and nickel nanoparticles. It has been shown that an electric field can inhibit or stimulate the adsorption of hydrogen on gold and the reduction of the oxidized surface of nickel nanoparticles with carbon monoxide. The mechanisms of the influence of the field on the chemical processes involving H 2 and CO are different. Quantum-chemical simulation has made it possible to determine the values of the energy barriers for CO adsorption on nickel nanoparticles.

Measurements are reported of the increase in catalytic CO oxidation rate on gold nanocoatings obtained by applying a positive or negative electrical voltage of variable magnitude to a coating. In experiments on an initial mixture of 1.8

Экспериментально определено увеличение скорости каталитического окисления СО на покрытиях из наночастиц золота при подаче на них электрического напряжения различной полярности и величины от внешнего источника. В условиях эксперимента при 430 °С, атмосферном давлении, начальном составе смеси 1.8% СО + 10.2% О 2 + Ar и начальном размере частиц покрытия 0.2–3 нм последовательное увеличение подаваемого положительного напряжения U вначале приводит к росту скорости окисления СО на 28% при U = +10 В, плавно снижающемуся до 20% при U = +30 В. Подача отрицательного напряжения менее эффективна: вначале скорость окисления растет на 12% при U = –10 В, а затем снижается до 7% при U = –30 В. Выполнены квантовохимические расчеты теплот ассоциации СО и О 2 с простейшим электронейтральным или электрически заряженным кластером золота Au 3 , а также теплот реакций Au 3 CO + O → Au 3 CO 2 и Au 3 CO 2 → Au 3 + CO 2 для различных зарядов Au 3 -содержащих комплексов. По результатам расчетов предложено объяснение увеличения скорости каталитического окисления СО на покрытиях из наночастиц золота, электрически заряженных с помощью внешнего источника напряжения.

The interaction of CO and H-2 with single clusters of gold and copper-based nanoparticles in the presence of an electric field has been studied. It is shown that depending on the direction of the electric field vector, the adsorption of molecules from the gas phase is stimulated or inhibited. Mechanisms of influence of the field on chemical processes are proposed.

The possibility of increasing the catalytic activity of a coating of gold nanoparticles during the oxidation of carbon monoxide (CO) by applying a positive electric voltage to the coating is experimentally established for the first time. Applying voltage U = +10 V to the coating increases the rate of CO oxidation by 28% at 430°C and atmospheric pressure for the initial mixture of 1.8% CO + 10.2% O2 + Ar.

The influence of the electric field on the interaction of CO with oxidized copper-nickel nanoparticles is studied. It is established that the restoration of the surface of nanoparticles is possible at potentials of φ ≤ +5 V applied to the sample relative to the ground potential, and at φ ≥ +5 V it is difficult. The most probable mechanism of the influence of the electric field on the reduction rate of the surface oxide is related to the spatial orientation of CO molecules.

Annually enterprises in the field of manufacturing of products from aerated concrete generate from 5000 to 10000 m 3 of solid production waste. One of the perspective and under-investigated direction is the practical application of solid waste using a porous aggregate in structural-heat-insulating lightweight concrete in the production of construction materials. The aim of this study was to evaluate the possibility of using crushed aerated concrete as a large aggregate in lightweight concrete for structural and thermal insulation purposes and to establish optimal conditions for obtaining products with the best characteristics. There were defined the qualitative indicators of crushed aerated concrete, analyzed factors influencing on the preservation of the properties of concrete in time, selected the composition of concrete aggregates from crushed concrete, studied the structure and properties of the obtained samples in the research. It has been found that to obtain effective constructive insulating lightweight concrete using waste production of aerated concrete as an aggregate is possible due to the fractionated pre-treatment of the aggregate with water dispersion of deep-penetration acrylic copolymers, insertion excess sealing water to concrete mixture, including optimization of the rheological properties of the concrete mix due to insertion of polycarboxylate hyperplasticizer.

Drawing in monolithic draw dies is the primary and often nonalternative pressure metal treatment (PMT) method used in the wire manufacture for various purposes both in our country and abroad. Its effectiveness largely depends on the wire diameter and properties. Thus, when drawing wire of large diameters (>8.0 mm) from high-carbon steels (high-tensile reinforcing wire, spring wire, etc.), the stability of the process and the probability of metal fraction decreases. The use of classic roller draw dies increases the strain uniformity along the wire cross-section, reduces the force and multiplicity of drawing. However, the «circle-shaped section-circle» roller gauge system used in this process leads to a more complicated process, and most importantly, to a significant increase in production costs. In this paper, a comparative analysis of the drawing efficiency of a round billet with a diameter of 16.00 mm from steel grade 80 into a wire with a diameter of 14.25 mm (strain degree 21%) in one step in the classic monolithic draw die and roller draw dies: three-roller draw die with a spatially closed round gauge and three-roller draw die of radial shear strain. The latter is comparable to the well-known radial-shear rolling. The difference is that the energy is introduced into the deformation zone by applying a front pulling force, and the idler rollers rotate around the wire with a special drive. The authors used finite element modeling in the Deform-3d software package. The deformed state in processes with linear tensile strain was estimated by the distribution of the accumulated strain degree in the billet cross-section, and in processes with torsion – by the change in the curvature of the line applied to the side surface of the billet. The power parameters were determined in Deform-3d in the coordinates: drawing force – time of billet movement. The stress state was determined by the hydrostatic stress on the wire axis and the Cockcroft-Latham fracture criterion. It is established that the wire strain in a monolithic draw die is characterized by a significant strain inhomogeneity across the cross-section, monotonous flow, high energy consumption, and the wire collapsibility, especially of the mid-layers. The use of draw dies with a spatially closed round gauge reduces the drawing force by about 40%, reduces the degree of strain inhomogeneity along the cross-section, and increases the degree of accumulated strain. The radial-shear strain drawing significantly increases the degree of accumulated strain and provides grain grinding, especially in the surface layers of the wire.

When foreign companies supply equipment for production of class A500 and B500 cold rebars to the Russian market, the manufacturer as a rule estimate its production indices by generally accepted parameters: machine utilization index (MUI), drawing speed and bars diameter (sometimes with specific differentiation). Usually, MUI and drawing speed are presented as the highest reached parameters without accounting particular conditions of operation at a customer, and sometimes – without configuration of the equipment. With a high price of equipment, a customer often gets low efficiency coefficient of correspondence between the high production parameters announced by the manufacturer and those being realized in practice. It was shown that drawing lines for production rebars of the class mentioned above, are typical by equipment content, for example unreeling and power segments. The difference can be only in coiling equipment segment. Such an equipment refers to equipment of cycling products discharge, which is done only at a coil change (a full coil for an empty one). Accumulation of tonnage is provided by a number of coils, which as a result (of a shift, day, month and a year) makes a production program of such drawing lines. If the change of coils at any coiler configuration (automatic, semi-automatic or manual) requires halt of the drawing line, then such halts must be accounted in the time balance of line operation and down times. Accounting of them can considerably change the announced production indices. Per se the production program of such drawing lines should be made taking into consideration actual MUI, but not the advertising one. Results of monitoring of contractual data of some foreign companies presented, to evaluate actuality of the announced by them indices of the equipment production program, supplied at the Russian market. The calculations of down times accounting change time and coils tonnage, as a relative index of drawing lines productivity and their analysis showed that the advertising data presented in the analyzed contracts, cannot be considered as representing and reference ones for making commercial production program of a customer. A method of calculation proposed and recommendations presented, which any customer can use when making inquiry for purchasing drawing equipment from any manufacturer. Also, the method can be used for internal monitoring of in-house production under conditions of particular state of engineer infrastructure and level of automation and mechanization of basic technological operations.

The paper presents the research results regarding the effect of compaction of highstrength prestressing strands of the 1х7 (1+6) design on changes in the stress-strain state of steel. After stranding wires in high-strength prestressing strands with strength of 1860 MPa, 12.5 mm in diameter, the strand should be compacted at a suggested degree of 6 %. This reasonable schedule of compaction contributes to a lower level of stranding stresses, integral strand geometry and residual stresses within the ranges compatible with residual stresses of stabilized prestressing strands. The paper includes the studies on mechanical properties of test specimens of compacted prestressing strands. A computer model of stranding and subsequent compaction of strands is used to factor in residual stresses formed at previous operations of strand production.

The increase in the rate of catalytic oxidation of CO on palladium nanosized coatings is measured when electric voltages of different polarities and magnitudes are applied to the coatings from an external source. Under the experimental conditions at 330°С, atmospheric pressure, and the initial composition of the mixture of 1.8% CO + 10.2% О2 + an Ar application of a positive voltage of +10 or +30 V to the coating leads to the CO oxidation rate increasing by 14 or 42%, respectively. Applying a negative voltage of –10 or –30 V results in less acceleration of oxidation by 4 or 12%. It is shown that the effect of the voltage supply does not depend on the particle size in the coating and increases linearly with increasing voltage. The quantum-chemical calculations of the heat of the association of CO and O2 with the simplest neutral or electrically charged palladium Pd2 clusters are calculated. It is found that the creation on Pd2 of a positive charge leads to a decrease in the difference between the heat of association of CO and O2 by 16.7 kcal/mol, while the creation on Pd2 of a negative charge leads to a smaller effect: a decrease in the specified difference by 10.6 kcal/mol. Based on the results of the calculations, an explanation is proposed for the increase in the rate of catalytic oxidation of CO on palladium electrically charged using an external voltage source is proposed.

МЕТОДИКА ОПРЕДЕЛЕНИЯ СТЕПЕНИ ГАРМОНИЗАЦИИ СТАНДАРТОВ РАЗЛИЧНЫХ КАТЕГОРИЙПолякова М.А. 1 , Дрягун Э