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The production of the radioisotope molybdenum-99 in the WWR-K research reactor is achieved through the activation method 98Mo(n,γ)99Mo, utilizing a target of natural molybdenum trioxide irradiated under standard conditions (thermal neutron spectra and water environment). Under such conditions, the maximum specific activity of molybdenum-99 reaches (2.3 ± 0.3) Ci/g Mo after 7 d of irradiation. However, the escalating demand for molybdenum-99 and the need to reduce its production cost, necessitates urgent and increased productivity. This study aims to optimize the irradiation conditions for molybdenum powder in the WWR-K reactor to increase the specific activity of molybdenum-99. For this purpose, we evaluated various irradiation capsule designs comprised various neutron moderator materials and thicknesses. Through extensive modeling calculations, we obtained an optimal capsule design that increases the specific activity of molybdenum-99 to 3.31 Ci per 1 g of Mo.

Background: Catheter ablation (CA) for ventricular tachycardia (VT) can be a useful treatment strategy, however, few studies have compared CA to medical therapy (MT) in the sarcoidosis population. Objective: To assess in-hospital outcomes and unplanned readmissions following CA for VT compared to MT in patients with sarcoidosis. Methods: Data was obtained from the Nationwide Readmissions Database between 2010 and 2019 to identify patients with sarcoidosis admitted for VT either undergoing CA or MT during elective and non-elective admission. Primary endpoints were a composite endpoint of inpatient mortality, cardiogenic shock, cardiac arrest and 30-day hospital readmissions. Procedural complications at index admission and causes of readmission were also identified. Results: Among 1581 patients, 1217 with sarcoidosis and VT underwent MT compared to 168 with CA during non-elective admission. 63 patients admitted electively underwent CA compared with 129 managed medically. There was no difference in the composite outcome for patients undergoing catheter ablation or medical therapy during both non-elective (9.0 % vs 12.0 %, p = 0.312) and elective admission (3.2 % vs. 7.8 %, p = 0.343). The most common cause of readmission were ventricular arrhythmias (VA) in both groups, however, those undergoing elective CA were less likely to be readmitted for VA compared to non-elective CA. The most common complication in the CA group was cardiac tamponade (4.8 %). Conclusion: VT ablation is associated with similar rates of 30-day readmission compared to MT and does not confer increased risk of harm with respect to inpatient mortality, cardiogenic shock or cardiac arrest. Further research is warranted to determine if a subgroup of sarcoidosis patients admitted with VT are better served with an initial conservative management strategy followed by VT ablation.

Background. The central element in a software-defined network (SDN) is a controller that plays a key role in the management and control of network devices. There was a need to research and develop a conceptual model of the SDN controller as the most important part of the network. The purpose of the study is to develop a conceptual model of SDN controller in the AnyLogic program to evaluate the efficiency of data transmission. Materials and methods. This paper examined the performance, resource management efficiency and security of the simulation model. The physical components of the network such as device resource, switching and control nodes are briefly described. An algorithm for traffic distribution, resource management, and control and security functions is developed. The operation of the circuit with the SDN controller is debugged, data is measured, and network performance shortcomings are found. The solution to these shortcomings is to increase the network throughput by increasing the capacity of network equipment. Various tests and evaluation of the performance, efficiency, and stability of SDN controllers and their impact on the network infrastructure were carried out. Results. Setup, configuration of SDN controller network was done. Network with different bandwidths were investigated. Delays and overflows with a set number of incoming packets were identified. Due to the software-defined network with separate control, control and fast configuration of components is possible, it was shown in the experiments. Conclusions. The conceptual model of the SDN controller circuit was considered. But on its basis the positive and negative sides of the scheme with SDN controller have been revealed, and the solution for increasing the network capacity has been revealed.

Technologies associated with using concentrated energy flows are increasingly used in industry due to the need to manufacture products made of hard alloys and other difficult-to-process materials. This work is devoted to expanding knowledge about the processes accompanying the impact of laser pulses on material surfaces. The features of these processes are reflected in the acoustic emission signals, the parameters of which were used as a tool for understanding the accompanying phenomena. The influence of plasma formations above the material surface on self-oscillatory phenomena and the self-regulation process that affects pulse productivity were examined. The stability of plasma formation over time, its influence on the pulse performance, and changes in the heat flux power density were considered. Experimental data show the change in the power density transmitted by laser pulses to the surface when the focal plane is shifted. Experiments on the impact of laser pulses of different powers and durations on the surface of a hard alloy showed a relationship between the amplitude of acoustic emission and the pulse performance. This work shows the data content of acoustic emission signals and the possibility of expanding the research of concentrated energy flow technologies.

We utilized a blend of replica exchange and event-chain Monte Carlo techniques to generate candidate configurations, aiming for a maximal packing fraction of hard disks within a circular enclosure. Our investigation encompassed systems comprising N particles, with N ranging from 300 to 720. Through our analysis, we identified 108 novel maximal packings, with some surpassing existing configurations by over 0.001 in packing fraction. As such, Monte Carlo methods demonstrate their efficacy in tackling optimization challenges of this nature. [ABSTRACT FROM AUTHOR]

Purpose: to develop a water-saving regime for irrigating corn for grain, which guarantees sustainable productivity with a shortage of water resources on the basis of field research. Materials and methods. The studies were carried out in Rostov region according to generally accepted methods. The soil of the plot is ordinary chernozem. According to water-physical and agrochemical indicators, it is suitable for crop cultivation. The experiment scheme included three options: in option 1 (control), a previously developed irrigation regime was used; in options 2 and 3, from the beginning of the growing season to the phase of tasselling, irrigation rates were given out completely (as in option 1), and then decreased by 15 and 30 %, respectively. Results. The pre-irrigation soil moisture limit in the 0–60 cm layer was maintained at the level of 70–75 % of the minimum water capacity. The soil water regime influenced the plant growth and development. The differences in the onset of plant vegetation phases were observed from the phase of tasselling. The grain firm ripe stage occurred in variant 3 earlier, then in variant 2. The largest linear growth in the flowering phase (269 cm) was recorded in variant 1, which was 3.7 and 5.2 % higher than the indicators of the variants 1 and 2, respectively. The biological yield of corn in option 1 was 12.9 t/ha, which is 10.1 and 16.3 % higher than the water-saving options. According to the calculations of economic efficiency, with a decrease in irrigation rates by 15 %, the cultivation of corn for grain is profitable. Conclusions. As a result of the research, a water-saving irrigation regime for corn for grain was developed and recommended for agricultural production, which provides for nine vegetation irrigations: the first and second – 300 cubic meters/ha each, the third – 400 cubic meters/ha, from the fourth to the ninth ones, irrigation is carried out at a rate reduced by 15 % – 425 cubic meters/ha. Irrigation rate is 3550 cubic meters/ha.

The object of the study is a preparation of ecotoxicant destructor based on bacterial strains of Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas délhiensis and associations of nodule bacteria Rhizobium loti with Lotus corniculatus. It is established, that during the simultaneous use of the bacteria and the legume Lotus corniculatus the rate of oxidation of petroleum hydrocarbons increases three times in comparison with the degradation rate of the pollutant after the separate use of each bacterial strain. We have received the preparation of ecotoxicant destructor – dry heterogeneous mass consisting of viable microbial cells of strains of P. delhiensis and R. lotus, seeds of leguminous plant Lotus corniculatus and delignified sawdust. Oil destructive activity of the preparation is proved in the course of microfield experiments. The degradation of ecotoxicants is proved by capillary gas chromatography-mass spectrometry with mass-selective detection. Bacteria of the strains, included in the preparation, are non-pathogenic for humans and animals, biocompatible, environmentally safe, stable, unpretentious to nutritional needs, technological, do not persist in environmental objects in the absence of a substrate for destruction. The technology of the production of the preparation is developed. The results of these studies demonstrate the possibility of practical use of the degradative potential of the preparation in the course of the implementation of the measures for soil reclamation, cleaning up ecotoxicants and restoring its ecological status.

A brief review of methods for increasing the diffraction efficiency of optical elements synthesized by direct laser writing is done. It is noted that the previously proposed methods for recording the topology of similar elements using volumetric or surface contour masks do not provide an ultimate solution to a problem of increasing the diffraction efficiency. The performed model and physical experiments on the fabrication of structures of surface-relief phase optical elements by recording zone profiles using oblique laser beams show the fundamental possibility of forming steep side walls of the reverse zone slopes and the feasibility of developing this technology based on laser image generators.

During the last years, the interest in the application of the additive manufacturing (AM), also known as 3D printing, becomes extremely popular in the various fields of the medicine including the dentistry. Currently, metal and ceramic materials are most often used for dental prosthetics manufactured by 3D printing. The yttria-stabilized zirconia (YSZ) ceramics has become the best alternative for metal-based dental restorations. In this regard, the main goal of this review deals with studying the effect of the 3D printing parameters on the macro- and microstructure and, accordingly, on the mechanical properties of the sintered YSZ, and on this basis, to give the practical recommendations to clinical dentistry and further prospects. As most researched in recent years, the 3D printing methods of such ceramics are the Laser-Stereolithography (Laser-SL) and the Stereolithography-Digital Light Processing (SL-DLP) based on the vat-photopolymerization technology and are discussed here. The physical foundations and the technological parameters of these AM technologies are considered. The main attention focuses on the effects of the thermal conditions during the 3D printing on the solidification microstructure (density, grain size, and crystalline phase composition), which is controlled by the manufacturing technologies. In addition, the true hardness and the biaxial flexural strength of the 3D printed YSZ samples are discussed. At last, the advantages of 3D printing ceramics in dentistry are mentioned.