Surfaces Of Units Research Articles

Efectividad de los desinfectantes Lysol® y Amonio Cuaternario durante la evaluación de tres áreas críticas del sillón odontológico

Objective. Determine the antimicrobial efficacy of Lysol® and quaternary ammonium during the evaluation of three critical areas of the dental unit (control tray/buttons, dental chair back, and triple syringe handle). Methods. Through a cross-sectional comparative experimental study, a total of 8 dental chairs were analyzed: three were disinfected with Lysol®, three with quaternary ammonium, and two armchairs were selected as controls (positive and negative). All dental chairs were sampled twice a day: before use and at the end of use, for three days. Sampling was carried out at the Hemisferios University Clinics before and after the application of the disinfectant. The samples were transported in thioglycollate broth for analysis. 1:2 and 1:10 dilutions of each sample were plated on Plate Count Agar and incubated for 24 hours at 37°C. Subsequently, duplicate colony counts were performed, analyzing a total of 864 samples. Results. Lysol® and 5% quaternary ammonium showed equal antimicrobial effectiveness against the three areas analyzed (p>0.05). The area with the highest number of microorganisms was the tray (including control buttons). Conclusion. It was determined that both Lysol® and 5% quaternary ammonium are highly effective in eliminating microorganisms present on the critical surfaces of the dental unit. Furthermore, the tray, including the control buttons, was found to be the most contaminated area before treatment.

IMPROVING THE PLANTS EFFICIENCY OF THERMAL INCINERATION HOUSEHOLD WASTE BY RECOVERING WASTE HEAT

The work is devoted to research on the creation of recovery exchanger for waste heat exhaust gases of household waste incineration plants. The purpose of the work is to develop a technical solution for the heat recovery exchanger of waste incineration plants (WIP) and determine its thermal efficiency indicators. The main objectives of the study were to analysis of the modern experience of using the WIP and establish requirements for the creation of a exhaust gas heat recovery exchanger, develop a new technical solution for the heat recovery exchanger, and determine the change patterns in its main thermal indicators in different operating modes of the WIP. The known methods of thermal calculation of heat exchangers and the results of previous studies on the development and implementation of heat recovery equipment operating on dusty gases were used. The results of work on the creation of a new technical solution for an air-heating heat recovery exchanger with the ability to clean working surfaces from dust deposits are presented. The heat exchange surface of the heat recovery exchanger is composed of steel panels formed by tubes with membranes. The tubes applied have circular flow turbulizators on their internal surfaces. Turbulizators provide heat transfer intensification by 1.4 to 1.8 times with a moderate increase in aerodynamic resistance compared to other methods of heat transfer intensification. The regularities of changes in the main indicators of the heat recovery unit in different operating modes during the year in the practical range of changes in its input parameters were established. The research results show that, depending on the initial temperatures of gases and air, the excess air ratio in exhaust gases and the dust level of the working surface, the heat recovery exchanger provides heating capacity of 72-263 kW; cooling of exhaust gases to a temperature of 107-245 °C; heating of air to 96-220 °C. It was also established that the deposition of dust on the heat exchange surface of the heat recovery unit under the considered conditions leads to a decrease in the heating air temperature by 1.3-1.4 times and an increase in the final exhaust gas temperature by 1.1-1.2 times. At the same time, the heating capacity of the heat recovery exchanger is reduced by half. To increase heat recovery efficiency, it is necessary to periodically clean the working surfaces of the heat recovery unit with compressed air.

Velocity and temperature distribution along the normal to the heat-transfer surfaces of in-reactor units under natural convection (generalization of experimental data)

Velocity and temperature distribution along the normal to the heat-transfer surfaces of in-reactor units under natural convection (generalization of experimental data)

Heat Transfer through Double-Chamber Glass Unit with Low-Emission Coating

The numerical modeling of radiation and convective heat transfer through a double-chamber glass unit was carried out to substantiate the increase in the heat transfer resistance of this unit via the application of low-emission coatings to glass surfaces. In the space between the panes of a window without low-emission coatings, the amount of heat transferred via radiation exceeds the amount of heat transferred via thermal conductivity and convection. The question of the effect of low-emissivity coatings on reducing heat loss through a window has not yet been sufficiently studied. This problem is also not sufficiently reflected in the literature. In this regard, this paper presents the results of numerical simulation aimed at studying the effect of low-emissivity coatings on heat transfer through a double-chamber glass unit. Simulation is carried out by numerically solving a system of equations of fluid dynamics and energy for the air gap and glass. Boundary conditions of the fourth kind are set on the internal surfaces of the chambers, taking into account the radiation and conduction components of the total heat flux emanating from the glass. The results of modeling heat transfer through a glass unit with ordinary glass show that about 60% of the heat is transferred by radiation. Therefore, an effective measure to reduce heat loss through windows is to reduce the radiation component of the total heat flux by applying a low-emissivity coating to the internal surfaces of the glass unit. This allows for the reduction of the overall heat flux (and, accordingly, heat loss to the environment) by 20–34%, depending on the number of glass surfaces with such a coating.

Theoretical study on structural evolution, photoelectron and vibrational spectra, and thermochemistry properties of neutral, anionic and di-anionic titanium-doped tin (TiSnn0/−/2− (n = 4–17)) nanoalloy clusters

The structural evolution, chemical stability, electronic and vibrational properties, as well as charge transfer and bonding character of TiSnn0/−/2− (n = 4–17) clusters have been performed with density functional theory calculations using ABCluster search technique. Structurally, it is found that the growth patterns prefer three kinds of absorbed stages from polygonal bipyramidal configuration for n = 4–6, to absorbing additional Sn on the adjacent surfaces of pentagonal bipyramid unit from n = 7–12, and finally to the TiSn130/−/2− cluster as the first foundational architectures, of which the encapsulated cage structure is formed when n = 11. The simulated PES spectra agree with available experiments. More interestingly, the neutral TiSn16 cluster not only possesses the high thermodynamic and relative stability but also preferable photochemical reactivity, that can be further explained by superatom features and delocalized multi-center bonds (AdNDP), while the strong p-d hybridization between Ti atom and Sn unit plays an important role in the stabilities of clusters, making it as the most suitable building units. In addition, the UV–Vis absorption spectra of TiSn16 are discussed, and the main transitions of crucial excited states are analyzed in detail. The Infrared and Raman vibrational characteristic peaks of all these neutral and charged species are properly assigned, of which the TiSnn0/−/2− (n = 10–17) clusters possess degenerating deformation mode of Ti atom wagging in Sn cage framework (Infrared active) and breathing mode of Sn cage framework (Raman active). All these findings will provide a further understanding for the nanoalloy cluster as the most suitable building block with further development as a potential optoelectronic material.

REDUCED HEAT LOSS THROUGH WINDOW STRUCTURES

The results of theoretical and experimental studies of heat transfer through the window structures of the building are presented, the thermal characteristics of the windows are established and the level of heat loss realized through them is estimated. To determine the heat transfer resistance of two-chamber double-glazed units, numerical modeling of radiative-convective heat transfer is performed, taking into account the thermal conductivity of the gas layer between the glasses. Natural free convection of the gaseous medium in the double-glazed chambers occurs as a result of the temperature difference between the side glass surfaces of the chamber. Modeling is performed by numerically solving the system of fluid dynamics and energy equations for the air layer and glass. On the inner surfaces of the chambers, conditions of the fourth kind are set, which take into account the radiation and conductive components of the total heat flow coming from the glass surface. The results of simulation of heat transfer through double-glazed windows with ordinary glass indicate that about 60 % of heat is transferred by radiation. Therefore, an effective measure to reduce heat loss through windows is to reduce the radiation component of the total heat flow by applying a low-emissivity coating to the inner surfaces of the glass unit. This makes it possible to reduce the total heat flow (and, accordingly, heat loss to the environment) by 20–34 %, depending on the number of glass surfaces with this coating. Conducted independent experimental studies confirm the modeling results. In order to comply with the current requirements of state building regulations and to achieve the energy efficiency class of type C buildings (specific heat consumption for heating 1 sq. m of usable area is less than 75 kWh), for the climatic conditions of Kyiv, it is recommended to use double-chamber windows with two low-emission coatings with the formula of the glass unit: 4M1-10-i4M1-10-i4M1. Bibl. 22, Fig. 8.

Method for Healing Corrosion-Caused Degradation of Concrete and Causes of Efflorescence

The emergence of efflorescence may be traced back to a complex web of interconnected processes that include many different paths. Efflorescence, in its most fundamental form, is the consequence of bringing water containing dissolved salts to the surface of masonry, letting the water to evaporate, and then allowing the salts to remain on the surface of the brickwork after the water has evaporated. Salt solutions have the potential to migrate either over the surfaces of masonry units, through the spaces between mortar and brick units, or via the pores of the mortar or brick units. In addition to this, salt solutions have the potential to seep through the pores of the mortar or the brick units.Alkaline solutions (often alkali metal silicates or hydroxides) combine with solid alumina-silicate precursors to create these binders (Davidovits, 1991, 2008). The transformation of a solid alumina-silicate precursor into a synthetic amorphous or nano-crystalline binder has been modelled in a simplified fashion by Provis et al. (2005). Their scenario begins with the oligomerization of silicate and aluminate monomers following the dissolution of a solid alumina-silicate source in an alkali-activator. Polymerization and gelation of the generated alumina-silicate oligomers can result in either an amorphous alumina-silicate phase or a Nano-crystalline zeolite phase, depending on the processing circumstances.

Mutational and Environmental Effects on the Dynamic Conformational Distributions of Lys48-Linked Ubiquitin Chains.

In multidomain proteins, individual domains connected by flexible linkers are dynamically rearranged upon ligand binding and sensing changes in environmental factors, such as pH and temperature. Here, we characterize dynamic domain rearrangements of Lys48-linked ubiquitin (Ub) chains as models of multidomain proteins in which molecular surfaces mediating intermolecular interactions are involved in intramolecular domain-domain interactions. Using NMR and other biophysical techniques, we characterized dynamic conformational interconversions of diUb between open and closed states regarding solvent exposure of the hydrophobic surfaces of each Ub unit, which serve as binding sites for various Ub-interacting proteins. We found that the hydrophobic Ub-Ub interaction in diUb was reinforced by cysteine substitution of Lys48 of the distal Ub unit because of interaction between the cysteinyl thiol group and the C-terminal segment of the proximal Ub unit. In contrast, the replacement of the isopeptide linker with an artificial ethylenamine linker minimally affected the conformational distributions. Furthermore, we demonstrated that the mutational modification allosterically impacted the exposure of the most distal Ub unit in triUb. Thus, the conformational interconversion of Ub chains offers a unique design framework in Ub-based protein engineering not only for developing biosensing probes but also for allowing new opportunities for the allosteric regulation of multidomain proteins.

Study of frictional properties, long-term (cyclic) strength of materials of brake pads of motor vehicles

Fractogram analysis shows that deep scratches, particles of titanium and chromium carbides and other elements were found on the friction surfaces. Moreover, in the braking devices there was damage to the large size of the brake pads of trucks. The transfer of particles of borides and carbides to the surface of the wheels can be explained by the processes of metal flooding with their subsequent embrittlement, which inevitably leads, as a rule, to the destruction of friction wheel pairs. It is established that such types of wear as fretting corrosion significantly (by 1.5-2 times) reduce the fatigue limit of parts. Also significantly reduce the cyclic strength of metal friction pairs oxide films on their surface in the absence of lubricant. The service life of friction wheel pairs has a particularly strong impact on fatigue strength. The main reason for the decrease in endurance due to the processes of setting on the working surfaces of friction units is a high concentration of stresses caused by deep tears, cuts, microcracks. The process of destruction of brake pads from fatigue begins from the surface of the part. In this regard, the quality of the surface, its structural-phase composition, physical and mechanical properties of the surface layer in most cases are decisive for the intensity of the development of wear processes of parts from fatigue of the tribosystem (friction wheel pairs), which are operated under cyclic loads. The peculiarity of the influence of friction and wear processes on the fatigue strength of metal is that at the time of running-in there is a change in surface roughness, structure and properties of surface layers. As the analysis of literature sources has shown, the effectiveness of the influence of friction and wear processes on the characteristics of fatigue resistance in the case of repeatedly alternating (cyclic) loads is essential, and therefore ignoring this effect during the traditional assessment of the reliability of parts by individual criteria, for example, wear resistance, often leads to an incorrect assessment of the operational durability of the elements of the tribological system of road or rail transport. The long-term (cyclic) strength of brake pads was determined on a specialized unit model 1251 by Instron company (Great Britain). The basis for spraying and surfacing of different types of coatings was normalized steel 35. Tensile-compressive deformations at zero average stress and a cycle frequency of 20 Hz were studied on the laboratory unit. Most of the tests were carried out in salt solutions (NaCℓ of industrial purity was used).The process of destruction of brake pads from fatigue begins with the surface of the part. In this regard, the quality of the surface, its structural-phase composition, physical and mechanical properties of the surface layer in most cases are decisive for the intensity of the development of wear processes of parts from fatigue of the tribosystem (friction wheel pairs), which are operated under cyclic loads. Endurance limits in the case of simultaneous exposure to friction forces and cyclic loads will depend on the sliding speed of the tangent surfaces of the normal contact load, which determines the friction force, and the composition of the environment.

Физический коэффициент профиля и его применение для моделирования текстуры механически обработанной поверхности

Current trends in the development of mechanical engineering impose increasingly stringent requirements for the performance characteristics of manufactured goods. The main parameters characterizing the quality of a product as a whole are the physical, mechanical, and geometric indicators of the working surfaces of the compound units. In domestic practice, a machined surface is mainly characterized by a rather limited number of parameters (no more than 6), such as the average microroughness height, the microroughness height at 10 points, etc. However, their use is not enough to manufacture competitive products in the modern conditions. For example, international ISO/ASME/DIN standards include a much broader set of parameters required to accurately describe the performance properties of a surface. The paper analyzes the approaches to the formation of requirements for the microgeometry of the working surfaces of parts used in modern mechanical engineering. Based on the analysis, the author proposed and mathematically substantiated a general approach to modelling surface texture characteristics, which allows describing adequately the surface using a new parameter – the profile physical coefficient, since it is virtually impossible to directly compare the technologies developed in Russia with foreign analogues based on the current standards. First, the profile physical coefficient was determined at the section level. Next, it was decomposed into a Fourier series for the two-dimensional and three-dimensional cases. The paper presents the analysis of the new parameter applicability on the example of a product obtained by honing. The author concluded about the applicability of this parameter and the necessity to develop a comprehensive methodology based on it for evaluating the surface after machining.

A study on electric pulse treatment of stainless steel constructive forming process

The constructive forming process is a new plastic forming process of manufacturing heavy forgings from small blank units. In this process, first, the surfaces of the blank units are cleaned, and then the blank units are packaged into a whole blank, finally, the whole blank is deformed into a heavy forging by thermal deformation in a vacuum. In order to solve the key problem of constructive forming which is bonding interface healing, electric pulse treatment was introduced to regulate and control bonding interface healing. Through the electric pulse treatment experiments of stainless steel blanks before and after high temperature deformation, the effects of electric pulse treatment on the geometric morphology, microstructure and chemical composition of stainless steel bonding interface were revealed. The results indicate that using electrical pulse treatment before high temperature deformation can pre-connect the bonding interface and promote the thermal deformation healing of the bonding interface, using electrical pulse treatment after high temperature deformation can promote the healing of micro-voids in the bonding interface area and further improve the healing effect of the bonding interface. The research results provide a new idea for solving the problem of interfacial traceless bonding technology in metal constructive forming.

Biological and Chemical Monitoring of Rostov NPP as Effective Tool to Prevent Biological Disturbances in the Circulation and Technical Water Supply Systems

The technical and circulating water supply systems of nuclear power plants use water from natural or technical water bodies to provide the water supply to the nuclear power plants. Individual elements and equipment of technical water, are called technical water supply systems. In technical and circulating water supply systems, biological fouling is a collection of microorganisms, algae, molluscs, sponges, bryozoans and other biological organisms that have settled and developed on the heat exchange surfaces of units, in pipelines and on the structures of circulating water coolers. This fouling is caused by the introduction of micro-organisms and dispersal forms of fouling organisms with water from the source. In order to prevent and eliminate biological fouling on the equipment of technical and circulating water supply systems of nuclear plants, Rosenergoatom Concern JSC has adopted a production programme aimed at regular biological and chemical monitoring of water supply systems of nuclear plants.

Mathematical modeling of the evolution of a tribosystem in the process of formation of equilibrium roughness of a frictional contact

As the science of friction developed, tribologists showed that reliable operation of friction units is determined by the wear resistance of the surface layer, its ability to adapt to changing operating conditions. In this regard, there is a need not only to create structures on the surfaces of friction units that have the properties of self-regulation and self-organization, but also to monitor changes in the characteristics of the surface layer. This article presents an innovative methodology for monitoring the life cycle of surface layers coated by vacuum ion-plasma treatment. In this paper, we propose a dynamic model based on the hypothesis that roughness is both a factor that excites mechanical vibrations and a consequence of these vibrations, whereas roughness changes as a result of wear under the influence of local dynamic forces. It is shown that a friction pair is a nonlinear system with complex feedbacks. Its stationary motion can be considered as a strange attractor. The randomness of motion in the vicinity of the limit cycle is due to the presence of a link of constant delay with rigid positive feedback in the model. As a result, there is constant reconfiguration of the amplitude and phase of the oscillations.

ЕЩЕ РАЗ ОБ ОПРЕДЕЛЕНИИ СОСТОЯНИЯ КРУПНОГАБАРИТНОГО ТЕЛА ВРАЩЕНИЯ

The paper proposes the author’s version of preliminary diagnostics of the state of rolling surfaces of large-sized technological units. The authors build their research based on the requirements of regulatory documents governing the conduct of equipment vibration diagnostics, and processing the results of the measurements obtained.
 The authors propose their own justified option for placing vibration sensors on the equip-ment elements, including the use of wireless sensors placed on the rotating equipment elements. At the same time, the choice of the proposed data transfer protocol provides real-time monitoring of the technological unit state, with significant dimensions of the equipment itself. In accordance with the standard requirements, these solutions ensure the reliable operation of technological units and equipment.
 The developed algorithm allows one to per-form a comparative evaluation in the diagnosed units and equipment elements and determine not only the defective element, but its type and approximate location on the element surface, which is necessary during the prerepair preparation.
 The results presented in the paper can be useful not only for researchers performing similar work, but also for production engineers involved in automating control and diagnostic processes, as well as performing equipment maintenance and repair

Quality parameters of interfaces of technological equipment units

The influence of design and technological measures to stabilize and increase the interaction of mating surfaces of technological equipment units on the quality of manufactured products is investigated. Keywords: technological equipment, accuracy, reliability, durability, movable and fixed joints, friction surfaces.serdobintsevyup@mail.ru

Improvement of electrospark deposition technology of steel units for drilling rigs and mining equipment

Introduction. The development of modern equipment and technologies for geological exploration and mining processes raises the problem of ensuring the reliability and durability of mechanic units operating under the conditions of elevated temperatures and pressures in the presence of aggressive external environments. In this regard, there is a need to create functional coatings with unique physical, mechanical and operational properties.Aim. To improve the performance of electrospark coatings based on an analysis of a cause-andeffect diagram and a regression study of the technological modes of processing steel units of geological exploration equipment (on the example of hydraulic cylinder rods of drilling pumps).Materials and methods. To harden the steel surfaces of hydraulic equipment parts, the technology of electrospark deposition (ESD) was used on an IMES-1001 mechanized installation using carbide electrodes and various gas media. In order to identify causal relationships between the factors affecting the hardened surface and to establish the most important factors affecting the quality of the formed coating, the Ishikawa diagram method was used and a regression analysis was performed. The adhesion activity of the obtained coatings was assessed by atomic force microscopy on a Solver PRO scanning probe microscope in a semi-contact air scanning mode using NSG10probe sensors with a resonance frequency of 219 kHz and a radius of curvature of the probe tip of 10 nm. When determining the strength of the adhesive interaction of the probe and the surface at one point, the absolute error was 15 nN. Tribological tests were carried out on a 2070-СМТ-1 standard friction machine according to the “disk-shoe” scheme.Results. The obtained cause-and-effect diagram showed that the technological modes of an electrospark deposition installation comprise a determining factor affecting the quality of the formed layers and coatings. In order to identify those process parameters that had the greatest effect, a regression analysis was carried out. The capacitance of the unit capacitors was found to have the greatest impact on the adhesion force formed by the ESD coating. Therefore, in order to reduce the strength of the adhesive interaction of surfaces and, as a result, increase their wear resistance, it is necessary to increase the capacitance of capacitors while reducing the voltage and processing time when implementing the ESD technology. On the basis of tribological tests, it is concluded that the minimum wear rate of coatings can be obtained by alloying the steel surface in an oxygen environment with a carbide electrode based on tungsten carbide with additives of elements that form unlimited solid solutions with the surface material and perform the role of fluxes (Ni-Cr-B-Si).Conclusion. Due to strict requirements to the performance of metal surfaces of units that enter into frictional interaction during the implementation of mining and exploration processes, there is a need to improve existing technologies for creating functional (wear-resistant) coatings.

Construction of a regression model for assessing the efficiency of separation of lightweight seeds on vibratory machines involving measures to reduce the harmful influence of the aerodynamic factor

When separating (cleaning) lightweight seed mixtures with the help of vibratory machines, there is an issue related to the harmful effect of air movement in the gaps between parallel working surfaces of vibratory machine units. This factor is particularly harmful to seed material, which is sensitive to air movement (some medicinal and vegetable crops). To address this issue, the design of vibratory machines is changed while their operational regimes are configured accordingly. This requires many full-scale experiments and (or) time-consuming personal computer-based simulation of the working processes of the vibrational motion of such seed mixtures. This paper proposes several regression models that make it possible to replace time-consuming numerical modeling with simple analytical expressions (regression equations). These equations are used for a quantitative assessment of the degree of influence of aerodynamics on the kinematic parameters of the vibrational motion of particles of seed mixtures. The assessment is derived depending on the geometric characteristics of the aerodynamic screen, the design of the unit, and the amplitude of oscillations of the working surfaces of a vibratory machine. The models take the form of equations of multiple linear regression of the second order, obtained on the basis of a series of numerical experiments. The processes of vibration movement of the seed material of parsnips, lettuce, and fragrant dill were investigated. The coefficient of determination equaled 0.956...0.967. The results reported here are useful for the construction of algorithms to optimize the design and adjust the operating modes of vibratory separators according to the criterion of minimizing the harmful effects of the aerodynamic factor

Improvement of corrosion resistance of internal surfaces in power-generating equipment

We investigate the possibility of using induction currents for improving the reliability of thermal power plants by increasing the corrosion resistance of internal surfaces of power-generating equipment, such as heating surfaces of boiler units. Corrosion resistance can be enhanced by improving the strength of an oxide film formed during passivation (oxidation). In this work, the oxide film strength was increased by electrochemical passivation of metal surfaces with induction currents. Using the method of multidimensional mathematical modeling of multi-parametric and multi-functional processes, we established that, for a continuous-loop economizer of a steam boiler comprising steel pipes with an inner diameter of 32 mm (24 coils operated simultaneously), an aqueous oxidant (oxygen) solution should be passed through the entire system of pipes for 4 h at an alternating current of 25 A. Under this treatment, oxygen should be added into the aqueous solution at a temperature of 130–450°C, an oxygen concentration of 1 g/kg, and a water flow rate of 0.5–5.0 m/s. Treatment intervals should be determined depending on the operating conditions of the equipment: reset, shutdown, or preservation. The efficiency of the method depends on the electric current passed over metal surface, treatment duration, oxidant concentration, as well as the type and size of the treated metal surface. The proposed passivation method can be used in both drum boilers and single-pass boilers. For example, it is recommended that passivation of water walls be carried out during boiler warm-up operation at 30–40% of boiler load, as well as passivation of superheat surfaces of boiler units and economizers. Therefore, the use of electrochemical passivation can increase the corrosion resistance of metal surfaces of power-generating equipment at thermal power plants.

Evidence of Antimicrobial Resistance from Maternity Units and Labor Rooms: A Water, Sanitation, and Hygiene (WASH) Study from Gujarat, India.

The main objective of this study was to determine the microbial contamination and antimicrobial resistance pattern among isolated bacteria from the environment surfaces of maternity units and labor rooms of healthcare facilities in the Gujarat state of India. The cross-sectional study was conducted in ten healthcare facilities, where the microbiological swab samples were collected from various pre-decided environmental surfaces of the maternity and labor rooms as part of the Water, Sanitation and Hygiene (WASH) assessment. The swabs were analyzed by conventional microbiological culture methods to identify microorganisms, including antimicrobial susceptibility testing. The study provides an insight into the microbial contamination of the visibly clean areas, i.e., the maternity ward, labor room, and general wards of the healthcare facilities. The labor rooms were found to be highly contaminated in comparison to other selected sites. The microbiological findings revealed a predominance of Gram-negative bacteria, specifically Pseudomonas species. The antibiotic susceptibility testing indicates resistance against many commonly used antibiotics. This study produces an identified necessity for enhancing microbiological surveillance in labor rooms and maternity units. This study also highlights the importance of microbiological status along with the WASH status of healthcare facilities.

ОБЕСПЕЧЕНИЕ ДИНАМИЧЕСКОЙ УСТОЙЧИВОСТИ ОБМЕРЗАЮЩИХ РОТОРОВ ТЕХНОЛОГИЧЕСКИМИ МЕТОДАМИ

The proposed article is devoted to artificial material systems operating in conditions of information scarcity for effective management. The problem is considered on the example of rotors operating in conditions of icing of surfaces of turbine units used in aviation and the thermal power complex. The analysis of measures to ensure the dynamic stability of rotors, whose surfaces are subject to icing, leading to an uncontrolled increase in local imbalances, is carried out. The relevance of the problem is due to both the general trend of scientific and technological progress aimed at improving technologies and types of products, and modern challenges of the economy. These should primarily include meeting the need for technological processes and types of products that are as close as possible to the requests in terms of the resource of work, cost, cost of operation and disposal. At the same time, the situation at the production site is complicated by the hostile attitude of the so-called Western countries to the development of Russian industry, especially in aviation, the thermal power complex, defense, elec-tronics, etc. All this creates a complex scientific and technical contradiction, burdened by a shortage of material support: financial inse-curity and the absence of a number of components supplied by previously unfriendly countries. Based on the results of the analysis of the dynamic state of the systems, the direction of its technological support is determined. Two methods are proposed to ensure the dynamic stability of the most problematic elements of rotors: wheels of centrifugal and axial compressors (turbines). At the same time, the method of precision preparation of rotor elements for assembly is designed to ensure the installation of the element on the shaft with minimized eccentricity of the forming seal and without imbalance, and the method of eccentricity-virtual assembly of turbine wheels is designed to balance the rotor with a pre–known imbalance. The application of the developed methods makes it possible to solve the formulated scientific and technical contradiction, significantly improve the quality of prod-ucts, reduce the labor intensity and cost of production. Technological processes using these methods have been tested in industrial conditions.