The paper presents the results of evaluating the propagation of a plane electromagnetic wave (EMW) over the surface of a film made of a high-temperature superconductor (HTS) in both superconducting S and normal N states, as well as an analysis of the parameters of a thin HTS film necessary for implementing a device for protection against electromagnetic radiation. Evaluation of the propagation of EMW over the surface of a thin HTS film was performed on the basis of a two-fluid model. As a result of the research, relations were obtained for determining the value of the surface impedance and the depth of penetration of EMW into a superconducting film in S and N states. It is shown that the expression for determining the penetration depth of EMW into a superconducting film in the normal N state is applicable provided that the frequency of the signal field does not exceed the critical value, which is determined by the binding energy of charge carriers at a temperature not exceeding the transition temperature to the superconducting state. Based on the relations for determining the surface impedance of a thin HTS film, relations are obtained for the active surface resistance, which is the real part of the surface impedance, and the surface reactance, which is its imaginary part, in the superconducting and normal states. Using these ratios, the quality parameter of the HTS thin film is introduced. The dependence of the quality factor of the HTS film on its thickness is found. It is shown that the highest value of the quality factor is realized when the film thickness is less than or of the order of the penetration depth. It is noted that this dependence is valid only if the film thickness does not depend on its quality. Keywords — superconducting film, electromagnetic wave, two-fluid model, surface impedance, penetration depth.
The object of research: morphological and cultural characteristics of micromycetes: yeast Saccharomyces cerevisiae and mycelial fungi Mucorracemosus grown on agar medium.The subject of research: flax seed suspension, ultrafine powder of double oxide of divalent and trivalent ferrum, micromycetes: yeast Saccharomyces cerevisiae and mycelial fungi MucorracemosusInvestigated problem: ensuring the bacteriostatic properties of raw materials and obtaining products with an extended dates of expiry.The subject in scientific results: the impact of nanoparticles (NP FeO×Fe2O3) on the bacteriostatic (protective) properties of flax seeds against fungal infections has been studied and the dependence of bacteriostatic properties on the amount of nanomagnetite has been determined. The ability of nanomagnetite to improve the bacteriostatic properties of flax seeds has been proven: addition of 0.1 %; 0.15 %; 0.2 % of nanomagnetite suppresses the development of microflora (micromycetes) in flax seed samples by 8–20 times. A reduction in the number of micromycetes (yeast Saccharomycescerevisiae and mycelial fungi Mucorracemosus) by 8–10 times and the size by 10–20 times was established compared to the control. The rational content of nanoparticles (NPs FeO×Fe2O3–nanomagnetite) has been determined as 0.15 % of the weight of the recipe mixture. The proposed mathematical model makes it possible to predict the effectiveness of using NP FeO×Fe2O3 – nanomagnetite to inhibit the growth of mycelial fungi to ensure the bacteriostatic properties of raw materials, in particular, flax seeds. The area of practical use of the research results: food industry enterprises specializing in the production of bakery and flour confectionery products using a mixture of wheat and rye flour with the addition of food additives. Innovative technological product: flour raw material with a mineral nano-additive suspension based on the double oxide of divalent and trivalent ferrum, which allows to ensure quality and extend dates of expiry of the product. Scope of the innovative technological product: to enhance the quality of food supply of the troops in extreme conditions
The article argues the relevance of determining the efficiency of the mixed system of maintenance and repair of road vehicles. Improving the system of maintenance and repair of road transport is one of the main ways to increase the efficiency of motor transport enterprises. This is due to the high growth rate of work performed, the significant complexity of the design of modern vehicles and the variety of implementation of new maintenance strategies and diagnostic methods. Significant complications in the design of components and units of modern road vehicles, increasing their functions, more busy modes of operation of components, units, etc. - significantly exacerbated the problem of traffic safety, which is largely due to the quality of maintenance and repair. The urgent need to improve the system of maintenance and repair is due to changes in the technical condition of automotive equipment and the requirements for maintaining the working condition of vehicles during operation. An analysis of existing maintenance and repair strategies has shown that each has its advantages and disadvantages. The combination of advantages of each strategy and elimination of shortcomings will lead to the creation of a mixed system of maintenance and repair, which along with high-quality staffing of repair companies and equipping them with modern diagnostic equipment will increase the readiness of road vehicles, technical efficiency and efficiency quality of operation, reduce maintenance and repair costs at a given level of reliability. © О. М. Рікунов, В. І. Кужелович, 2022 Keywords: road transport vehicles, maintenance and repair system, preventive maintenance system, average total duration of maintenance and repair, technical readiness coefficient, technical utilization coefficient, economic feasibility
Bakery products have an unstable heterogeneous structure that needs stabilization. The nutrient composition of these products, in most cases, is unbalanced: it is characterized by a high content of calories and carbohydrates. At the same time, the content of protein, fat, dietary fiber (fiber), vitamins, macro- and microelements is low. This leads to the search for raw materials with high functional and technological potential and with an attractive nutrient profile. The expediency of using in the technologies of bakery products a secondary product of processing sunflower seeds – flour from the extruded kernel of sunflower seeds (FESSK) has been proved. Its nutrient profile has been investigated. A high protein content (38.73 %) with a well-balanced amino acid composition (10 essential and 9 non-essential amino acids) increases the biological value of FESSK. The content of fat (4.87 %), rich in unsaturated fatty acids (16 fatty acids), enriches the nutritional profile of FESSK. The high ash content (8.0 %) (22 elements were found) and the presence of 12 vitamins (92.3 % of the total amount of vitamins) indicates a high biological value of FESSK. It was found that the addition of FESSK in the amount of 10.0 % to the mass of wheat flour increases the humidity by 0.5–1.2 %; reduces acidity by 0.5–1.2°; increases porosity by 7.0–11.0 %; increases the specific volume by 1.12–1.26 cm3/g. It reduces crumbliness of the crumb by 2.0–2.2 times, QMAFAnM – by 4.0–4.8 times, and increases the period of preservation of bread freshness by 1.57–1.77 times
The work describes a general approach to dynamic processes modeling under action of pulsed reactive forces of recoil during firing shots from combat modules weapons. The combat module can be presented as a discrete system; this approach also applies to elements of drive, engine, transmission, etc. They are characterized by a local compact concentration of mass and high rigidity of the structure itself compared to the same armored hull or special elastic elements of suspension system. Then the reaction of this complex mechanical system to the action of dynamic forces is of interest. On the basis of the developed approach to analysis of the dynamic response of the combat module of a lightly armored vehicle equipped with a small-caliber automatic gun to the action of reactive recoil forces, it is proposed to carry out a qualitative analysis on simplified models at the first stage. The influence of a single shot and burst firing on the deviation of the axis of the barrel from the direction to the target is analyzed. For this, a simplified test model was built. Further, on the obtained simplified models, the results are compared with the results of the analysis on more complex models. The introduced piecewise linear approximation dependence of the time distribution of the reactive recoil force makes it possible to parametrize such force distribution with one parameter. As evidenced by the research results, the nature of the response of the studied dynamic system is strongly influenced by the damping level. If the damping level is high, and the frequency of the pulses is not a multiple of the natural oscillations frequency then the influence of individual pulses can be considered in isolation from each other. The characteristic features of the transient and stable modes of movement of lightly armored vehicles combat modules are determined. These qualitative features determine the nature of the response of the dynamic system to the action of a single pulse and to the action of a series of such pulses. The same features are also characteristic of systems with a large number of degrees of freedom, as well as systems with distributed parameters. Keywords: dynamic system, combat module, lightly armored vehicle, transition process, steady process, integration of differential equations system, reactive recoil forces during firing shots
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