The article provides theoretical substantiation for the necessity of analyzing the joint operation of the mechanical and hydraulic subsystems of a magnetorheological hydraulic anti-vibration mount (MR hydromount). Experimental studies are conducted on MR hydromounts OGM-95 with a low eigenfrequency. It is confirmed that the mechanical and hydraulic subsystems of MR hydromounts require configuration in order to achieve the greatest vibration damping in the pre-resonance frequency region. The mounts are controlled by synchronous configuration of the phase and frequency of the control signal of the magnetorheological transformer with the fundamental oscillations harmonic reaching the frequency of mechanical resonance of the MR hydromount.

A problem of the longitudinal impact of a ram with a punch on a forging for an impact press is solved using the finite difference method. An algorithm is presented for calculating the maximum deformations and stresses of an elastic polyurethane liner when a self-resetting force fuse is triggered for a KD2124 crank press with a force of 250 kN. The solution can be used to develop a concept for constructing a means of protecting impact crank presses from technological overloads.

Today, the contribution of the microbiota to the genesis of many diseases, including endometriosis, is widely discussed. However, the literature data on the microbiological composition of endometriosis are contradictory. In addition, data indicating the effect of conservative therapy on the microbiological composition are limited only to estrogen-containing drugs, while there is no data on the effect of progestogens. Objective: to evaluate the composition of the intestinal microbiota of patients with external genital endometriosis on oral progestogen therapy. A single-stage pilot study was conducted, which included 17 patients with external genital endometriosis (average age 30.9 (7.8) years, average body mass index 20.2 (2.0) kg/m 2 ). The women received oral progestogen therapy (dienogest at a dose of 2 mg per day in a continuous mode). Microbiological examination of faecal samples by culturomics methods with inoculation on selective and non-selective nutrient media, followed by species identification of microorganisms, was carried out using time-of-flight mass spectrometry (MALDI-TOF MS) at two points: initially and after 6 months of taking dienogest. Dienogest therapy showed an improvement in a number of microbiological indicators of the intestinal microbiota in the form of a tendency to increase species and taxonomic diversity, a decrease in the Bacillota / Bacteroidota index, and a decrease in the titer of conditionally pathogenic microorganisms Staphylococcus spp. and increased colonization of symbiotic bacteria of the Collinsella aerofaciens and Lactobacillus spp. Thus, dienogest therapy can have both a direct and indirect effect on the composition of the intestinal microbiota of patients with external genital endometriosis, which was demonstrated by the results of the study.

The article describes the course of vibration measurements at a particular metallurgical plant, one of the workshops of which is equipped with vibration mills, from the formulation of the problem to the analysis of the results. The problem lies in the low quality of the floor on which four RVM-45 vibratory mills of the RVM-45/131.01 design are located, causing periodic loads and vibrations. The paper presents the results of vibration tests obtained through measurements at various points in the room during the startup, operation and shutdown of mills. The studies were carried out using a measuring device “Vibran-2.1”. The reason for the occurrence of progressive vibration caused by the intearactive operation of vibration mills RVM-45 is revealed. Ways to reduce the overall level of vibration in the room with the simultaneous operation of all mechanisms are proposed.

A method is proposed for measuring the eccentricity of rotating shafts that connect electric motors to various energy transducers. A functional diagram is developed for a device permitting acoustic measurement of shaft eccentricity. The time for shaft compression and the shaft’s torsional angles are determined in the cases of zero and maximum eccentricity.

A method is proposed for determining the maximum shear strain and stress of elastic shafts in magnetorheological couplings, on the basis of the finite-element method. To determine the angular mismatch of the coupling, the torque may be established by measuring the torsional deformation of the shafts, using broad-band frequency modulation.

A method based on finite differences is proposed for calculation of the conical rubber casing of a hydraulic support. This method is used in the design of metal–rubber hydraulic supports for vibrational protection.

The use of magnetorheological suspensions in damping systems for impact loads is proposed. The physical principles and engineering methods of producing magnetorheological fluids are considered, along with potential control methods. In producing ferromagnetic powder, a vortex cavitation system may be used. That ensures constant size and shape of the grains and rules out inclusions; it is also a high-speed process. The responsiveness of the powder to the magnetic field permits improvement in the acoustic cavitation process by adding a vortical magnetic field of the required frequency.

Magnetorheological hydraulic mounts are considered. Methods of controlling their dynamic stiffness and improving their damping properties are discussed. To that end, it is necessary to reduce the hydraulic drag on the flux of magnetorheological fluid in the mounts. That entails increasing the number of choke channels in the baffle plate. The dynamic stiffness of the magnetorheological hydraulic mount is calculated as a function of the magnetic field strength and the temperature of the fluid.

В статье рассмотрена задача измерения угловой деформации вращающихся валов. Выявлено, что изменения фазы отраженного акустического сигнала относительно опорного, падающего на исследуемую поверхность вращающегося вала, можно проводить с погрешностью 0,6% при скоростях не более 0,5 м/с.

Relevance. Acute respiratory infections (ARI) are a serious health problem not only because of the high frequency of their occurrence, but also because of the economic damage they cause both in the form of direct costs (the cost of diagnosis and treatment) and indirect costs (disability, reduced labor productivity, etc.). Pregnant women and children under 5 years of age are included in the group of patients with risk factors for complications of influenza and other ARI, therefore, an analysis of the etiological structure of ARI and influenza in obstetric hospitals is an urgent task. In recent years, there has been an urgent need to create a national complex diagnostic test system based on molecular genetic methods for detecting infectious agents that cause ARI. Aims. The aim of the study is to analyze the etiological structure of ARI and influenza in patients with clinical symptoms and to develop and implement a new test system for rapid screening and diagnosis of infections that cause ARI. Materials & methods. When studying the etiological structure of ARI and influenza, cultural studies of the nasal and pharyngeal mucosa were carried out, followed by identification of microorganisms using MALDI-TOF mass spectrometry and molecular genetic study (real-time PCR) using an experimental test panel containing primers that allow detecting the following viruses: influenza A, B viruses, parainfluenza viruses of the 1st, 2nd, 3rd and 4th types, coronaviruses OS43, HKU1, NL63, E229, respiratory syncytial virus, metapneumovirus, rhinovirus and adenovirus, as well as bacterial pathogens of ARI: Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes, Moraxella catarrhalis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa. The test system was developed using the following methods: real-time PCR, a combination of reverse transcription and real-time PCR (RT-PCR) and the next generation sequencing (NGS) method. Results. The etiological structure of ARI and influenza was analyzed in patients with clinical manifestations (cough, tickling/sore throat/hyperemia of the mucous membrane of the palate and the back wall of the pharynx, shortness of breath/difficulty breathing, acute runny nose/nasal congestion). The species spectrum of bacterial and viral pathogens was revealed. A new test system based on PCR, real-time RT-PCR and NGS has been created for complex diagnostics of both viral and bacterial pathogens of ARI, consisting of three separate components: the main test system «ARI», which detects the main viral and bacterial pathogens of ARI, and two additional sets of reagents: «Oseltamivir resistance» and «Oseltamivir/ Zanamivir resistance». Conclusions. The new test system can be used to detect and differentiate nucleic acids of pathogens of ARI of humans. The test system seems to us promising for further use. As a result of the analysis of the etiological structure of acute respiratory infections and influenza, attention is drawn to a significantly smaller variety of identified pathogens in 2020 and a much more pronounced dominance of rhinovirus infection compared to our previous study in 2019.

The influence of the reduced mass of the working fluid in the throttle channels of a hydraulic mount on its motion and damping is considered. The acceleration and velocity of the working fluid is found to depend on the reduced mass since the throttle channels are of different cross-sectional area.

The influence of the magnetic field on the sensitivity of magnetorheological working fluids in the slot-type throttle channels of magnetically controlled hydraulic mounts is investigated. Steady flow of an incompressible liquid with fixed electrical conductivity is considered, under the action of a uniform magnetic field. With increase in field strength, the magnetization of the working fluid declines. The exciting current of the electromagnet must be increased in order to compensate for this decline.

Measurements were carried out at different points of the machine and workshop using the vibrometer “Vibran 2.2”. At the step of studying vibration spectrograms it was found that shock loads significantly prevail over vibration, and the main harmonic of vibration is characterized by a frequency of 7…8 Hz corresponds to the rotation frequency of the middle shafts of the machine. Theoretical methods have established the cause of the progressive vibration generated by the rotation of the massive shafts of the paper-making machine caused, on the one hand, by the bearings wear accompanied by deformation of the rings and mutual displacement of their axes of rotation and, on the other hand, by an increase in the radii of the eccentricity of the shafts, leading to increase in dynamic loads acting on the bearing units. The authors of the article, who are directly involved in the vibration diagnostics of the machine came to the conclusion that in order to reduce its vibration it is enough to replace bearings with new ones which due to prolonged operation (more than 25 years) and the influence of vibration and shock loads have long worked out their service life.