Studying the Normal Operation of Grain Harvesters within the Warranty Period

Introduction. Grain harvesters are used for no more than two months within a year. They must have maximum operating reliability, since even short downtime during the harvesting period result in large crop losses. The purpose of the study is to identify the causes of combine harvester failures within the warranty period. Materials and Methods. Identifying consequences of failures and ensuring the reliability of grain harvesters are based on an improved classification of failures. In the process of studying, there have been proposed the ways to solve the problem of combine harvester downtime based on the analysis of the time for grain harvester troubleshooting. The category of severity of failure consequences was taken into account. Results. Through monitoring in the period from 2018 to 2020, there were found failures of units and systems of grain harvesters with low reliability indexes within the warranty period. Most of the failures (59.2%) were found in Russian-manufactured combines, of which operational failures are 55.9%, structural failures – 26.7%, and production failures – 17.4%. The general patterns of changes in the average time for combine troubleshooting have been determined. A geometric model of a detail for the trouble-free operation of combines (header auger shaft) was created. The finite element analysis (ANSYS) was used to identify parts, which are subject to maximum workload. There have been identified units and parts, which fail to function within the warranty period, because of design and technological defects. Discussion and Conclusion. In order to reduce the time to find the consequences of failures, it is necessary to create a more extensive network of enterprises providing a wide range of services, improve the organization of technical service and expand direct links with the manufacturers of equipment in order to respond quickly and make the necessary design and technological decisions

Contemporary Approach with Mitral Valve Allograft in the Treatment of Tricuspid Valve Pathology

Symptomatic tricuspid valve diseases are associated with a high risk of heart failure and poor prognosis. The current valve substitutes still carry the risk of associated complications. Allografts have been considered a valuable surgical option for decades since the first reports were introduced. The challenging surgical technique along with controversial results and homograft shortage discourage surgical society from wider use of allografts in tricuspid surgery. The largest world surgical experience with mitral allograft in the treatment of tricuspid valve disease is described in the study. A total of 20 patients underwent tricuspid valve replacement by mitral homograft in two clinics from October 2021 to February 2023. Surgical technique and initial results are presented in the chapter. There was no early mortality, postoperative bleeding, myocardium infarction, stroke, or sternal wound infection. Two patients needed permanent pacemaker implantation after redoing surgery before discharge. In the follow-up period, two patients suffered from a relapse of infective endocarditis in 3 and 6 months postoperatively with moderate homograft dysfunction, none of them underwent reintervention. There was no late mortality or permanent pacemaker implantation in the follow-up period. Satisfactory clinical and hemodynamic results, reproduceable technique and accessibility make homografts plausible valve substitutes in tricuspid surgery

Uncovering New Economy Potential of Russian Regions on the Basis of the Last 20 Years Dynamics’ Analysis

Recent global events have accelerated new technologies implementation worldwide. This process can likely lead to a future increase in regional disparities, especially in large developing countries such as Russia. Resource-based growth, which prevailed in the last 20 years in Russia, could slow down technological change in most regions. We aimed to assess regional potential for new economy formation based on its previous dynamics in 2000–2020. For that purpose, we developed a complex index that evaluates regional ability to create, use and disseminate new knowledge and technologies. There were long-term upward trends of most of the indicators in Russian regions due to intensive interregional alignment policy and a rapid spread of information and communication technologies. Economic growth, according to the Granger test results, contributed to the new economy formation. However, many research and development (R&D) indicators did not achieve higher values in comparison with 2000, when the oil prices started to grow. The growth rates in recent years have been low, and the share of R&D employees and R&D expenditures as well as entrepreneurial activity have declined especially in 2020. A significant but decreasing divide remains between leading and lagging regions. In accordance with the identified types of regions, it is necessary to pursue a diversified regional policy. Our results can be used to justify smart specialisation principles in Russia. Indirectly the study measures the resilience, or adaptability of regions to crises

Uncovering New Economy Potential of Russian Regions on the Basis of the Last 20 Years Dynamics’ Analysis

Recent global events have accelerated new technologies implementation worldwide. This process can likely lead to a future increase in regional disparities, especially in large developing countries such as Russia. Resource-based growth, which prevailed in the last 20 years in Russia, could slow down technological change in most regions. We aimed to assess regional potential for new economy formation based on its previous dynamics in 2000–2020. For that purpose, we developed a complex index that evaluates regional ability to create, use and disseminate new knowledge and technologies. There were long-term upward trends of most of the indicators in Russian regions due to intensive interregional alignment policy and a rapid spread of information and communication technologies. Economic growth, according to the Granger test results, contributed to the new economy formation. However, many research and development (R&D) indicators did not achieve higher values in comparison with 2000, when the oil prices started to grow. The growth rates in recent years have been low, and the share of R&D employees and R&D expenditures as well as entrepreneurial activity have declined especially in 2020. A significant but decreasing divide remains between leading and lagging regions. In accordance with the identified types of regions, it is necessary to pursue a diversified regional policy. Our results can be used to justify smart specialisation principles in Russia. Indirectly the study measures the resilience, or adaptability of regions to crises

Security of major pipelines in presence of terroristic threats: prognostic estimates

The purpose of the paper is to substantiate the approach to determining the required probability of detecting unauthorized attempts to contact the pipe shell to maintain a minimum level of pipeline security losses. That is also nesseccerly to assess probability trend in the near future. Based on the information obtained it is planned to propose the structure of the physical pipeline security system to neutralize terroristic attacks. Results of studies of vibroacoustic oscillations in the shell of a major pipeline during its operation are given. The mechanisms of change in parameters of a vibroacoustic pulse excited at a local point of a pipeline when it is propagated through a pipeline are expalined. Results of studies on the solution of the problem of detection and prevention of emergencies in the protected zone by seismic oscillations are considered. It is concluded that it is possible to detect precursors of emergencies by vibroacoustic and seismic vibrations of the pipe shell. The effectiveness of the proposed approach to determine the requirements for systems of protection of objects from terroristic threats is demonstrated. The region was chosen in accordance with available published data for a relatively long period of time, necessary for setting up a computational experiment. It is interesting to receive prognostic estimates in that segment of economy for the country as a whole. Presence of such information allow creating a policy for detecting terroristic attacks and deciding on the requirements for the physical protection system that have to be provided in the current period and short term. Today, there is no way to effectively fight with prepared violators to achieve their goals using any of the known single-sensor systems. It is concluded that there is a need to develop a multi-sensor system, minimum equipment of which should include interconnected seismic and vibro-acoustic subsystems. Combination of vibro-acoustic and seismoanalytical subsystems allows compensating the most significant drawbacks of each of them

Surgical treatment of trophoblastic disease. Modern concept and contradictions (literature review)

A review of studies on the comparison of the effectiveness of surgical treatment of malignant trophoblastic tumors before the start of standard chemotherapy and in terms of combination treatment is presented. According to Russian and foreign studies, surgical treatment is relevant for patients with primary or metastatic tumor resistance. The article presents the results of treatment of patients after various types of operations. The most common volume of surgery was a hysterectomy. The article also discusses the results of treatment of benign forms of trophoblastic disease. Surgical treatment of a malignant trophoblastic tumor before the start of standard chemotherapy was performed according to vital indications or in connection with a tumor determined by imaging methods. And the analysis carried out in Blokhin National Medical Research Center of Oncology showed expected prognoses for patients who underwent surgical treatment prior to the start of standard chemotherapy regimens. Such patients were admitted to the clinic with a resistant or disseminated form of the tumor. During their treatment, high-dose chemotherapy or additional surgical interventions were required, which significantly worsened the prognosis of the disease. In the opposite case, when removing a localized resistant primary tumor or its metastasis, in the postoperative period, chemotherapy was not carried out in connection with marker remission

Influence of scattering processes on electron quantum states in nanowires

In the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector

Формирование фотоприемных структур ИК-диапазона путем пересыщения кремния теллуром

The Si layers doped with Te up to the concentrations of (3–5)1020 cm–3 have been formed via ion implantation and pulsed laser melting. It is found, 70–90 % of the embedded impurity atoms are in substitution states in the silicon lattice. These layers have revealed significant absorption (35–66 %) in the wavelength λ range of 1100–2500 nm. In this case, the absorption coefficient increases with the λ growth. The absorption spectra of the implanted layers after pulsed laser melting, equilibrium furnace annealing, and rapid thermal annealing have been compared. It is shown that equilibrium furnace annealing increases the photon absorption by 4 % in the wavelength range of 1100–2500 nm in comparison with virgin Si. After rapid thermal annealing, the photon absorption in the IR-range increases only by 2 %.Слои кремния, легированные теллуром до концентраций (3–5)1020 см–3, получены ионной имплантацией с последующим импульсным лазерным отжигом. Показано, что 70–90 % внедренной примеси находится в позиции замещения в решетке кремния. Слои, гиперпересыщенные теллуром, проявляют существенное поглощение (35–66 %) в области длин волн 1100–2500 нм, причем коэффициент поглощения увеличивается с ростом длины волны. Проведено сравнение спектров поглощения имплантированных слоев после лазерного отжига, а также после равновесного и быстрого термического отжигов. Показано, что равновесный отжиг после имплантации ионов теллура увеличивает поглощение фотонов в области длин волн 1100–2500 нм на 4 % по сравнению с неимплантированным кремнием. После быстрого термического отжига поглощение в ИК-области возрастает лишь на 2 %