bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Radiation Embrittlement Trend Curves: Machine Learning and Multilevel Modeling
Authors: Lee Gyeong-Geun , Kim Min-Chul , Lee Joonho , Lee Bong-Sang
Published: June 2023

Machine learning (ML) has been a widely used tool for recognizing patterns in an extensive database with increasing computing power. This study applied three ML techniques—Cubist, support-vector machine (SVM), and XGBoost (XGB)—to fit the BASELINE surveillance test database. The rule-based Cubist and tree-based XGB models showed a significantly lower root-mean-square deviation than the SVM and ASTM E900-15 nonlinear model. ML showed a good capability for prediction in the interpolation region of the dataset. However, there were significant errors in the extrapolation region in predicting the effect of large fluence on the transition temperature shift (TTS). ML can be very useful in the development of a preliminary model because it can quickly capture the trend of the dataset. To improve the prediction of the TTS trend with fluence in the grouped data with the same initial Charpy impact property, a varying intercept model was introduced into the ASTM E900-15 trend curve, and the model coefficients were estimated by a multilevel modeling procedure. This model considered both the trend of all data and the trend of each group. It then provided more reliable intercepts in each group for TTS prediction with fluence. The multilevel modeling of the grouped datasets can increase the predictive power of the embrittlement trend model for commercial power plants.
Trend Curves for WWER RPV Materials and Their Supported Structures
Authors: Margolin Boris , Yurchenko Elena
Published: June 2023

Trend curves for WWER RPV materials (2.5Cr-Mo-V steel and its weld metal and 2Cr-Ni-Mo-V steel and its weld metal) and their supported structures (low-strength, low-alloy structural materials and welds) are presented. The main mechanisms of radiation and thermal embrittlement for RPV materials and support structures are considered, and service and metallurgical factors are taken into account.
Challenging Embrittlement Trend Curves with Lower-Than-Usual Irradiation Temperature Data
Authors: Chaouadi Rachid , Uytdenhouwen Inge , Puzzolante Jean-Louis
Published: June 2023

A series of irradiation-induced embrittlement trend curves was developed in the last decades and gathered in an Excel spreadsheet called PLOTTER to compare the various predicted values with the experimental data. A number of reactor pressure vessel materials, including forgings, plates, and welds with a variety of chemical compositions, were irradiated in the BR2 reactor to a neutron fluence ranging from ∼3 to ∼9 × 1019 n/cm², E >1 MeV at lower-than-usual irradiation temperatures (∼100 and 150°C) complemented with medium- to high-temperature irradiation data (260, 290, and 305°C) for comparison. Charpy impact tests were performed to determine the ductile-to-brittle transition temperature and the upper-shelf energy level. In addition, some tensile tests were also performed to determine the irradiation-induced hardening. Test results in terms of irradiation-induced hardening and embrittlement were determined and compared with the different embrittlement trend curve predictions. The results are discussed in the perspective of assessing the performances of the various embrittlement trend curves.
Radiation Embrittlement Surveillance and Trend Evaluation in Hungary
Authors: Gillemot Ferenc , Cinger Dávid , Szenthe Ildikó , Horváth Márta , Móritz Szilvia
Published: June 2023

The scatter of the existing trend curves is too large for the WWER-440 reactors operated in Hungary because the end-of-life fluence of these units are out of the validity range of the existing trend curves with the exception of the Russian trend curves. The RPV wall material of the WWER-440 reactors is the 15Kh2MFA low-copper, low-nickel, and vanadium-killed steel. The microstructure and irradiation damage mechanisms of 15Kh2MFA deviate from the other RPV materials. The surveillance specimens in the WWER-440 units are located near the core, the lead factor is between 12 and 18, and the irradiation embrittlement after 4 to 5 years of exposure corresponds to about 50 to 80 years of irradiation of the RPV wall and welds. The surveillance sets contain Charpy specimens, tensile specimens, and three-point bend specimens for fracture toughness evaluation. The surveillance database in the European countries is increased by the results of extended surveillance programs and testing reconstituted specimens. For each unit sufficient high-fluence data were available at the first years of operation to directly evaluate the Charpy and Master Curve shift, and therefore the use of embrittlement trend curves is unnecessary.
Thermal Aging of LAS Weld Metal from Decommissioned Nuclear Components in Swedish PWRs
Authors: Roudén Jenny , Blomström Johan , Efsing Pål , Berglund Martin
Published: June 2023

Thermal aging has been considered a secondary aging and degradation mechanism for the low-alloy steels used in nuclear power plants. Given the relative interest in lifetime extensions, this has to be revised considering the extent of time at temperature during a 60-year operation time or even beyond. Traditionally, the effect has been coupled to the nonhardening effects caused by phosphorus and sulphur diffusion to available phase or grain boundaries, or both, resulting in a marked embrittlement of these low-alloy steels. This phosphorus segregation is proposed to be the main embrittlement mechanism for the weld metals investigated in this study. In the high-manganese/nickel/silicon-bearing weld metal used in both pressurizers (PRZs) and reactor pressure vessels (RPVs), some of the material extractions from the Ringhals power plant show a larger than expected effect from thermal aging, possibly by the formation of agglomerates in the matrix due to higher nickel content. Further, some of the tested materials showed a hardening effect after in-service exposure at temperature. The results presented here show that even though there are elements to be included in the fitness-for-service analysis of the power plants, with traditional prerequisites for the RPV it will be limited regarding the operating window. An empirically based embrittlement trend curve, related to thermal aging, for the PRZ will be developed after further testing of these materials.
Experience with Embrittlement Trend Curves in Swedish PWRs
Authors: Blomström Johan , Roudén Jenny , Efsing Pål
Published: June 2023

There are currently two operating pressurized water reactors in Sweden, currently planning for 60 years of operation until 2041 and 2043. The acceptance of operation time is continuously evaluated at least every 10 years in a comprehensive mandatory periodic safety review that requires the utilities to continuously update and implement the developments in science and technology. The RPV welds have been shown by the applied surveillance program to be the limiting material for operation. The welds are manufactured according to the same specifications with a chemical composition with high nickel and manganese content. The welds show a large increase in transition temperature shift with an almost linear relationship to neutron fluence that is underestimated by most of the established embrittlement trend curves (ETCs). The current regulations from the Swedish Radiation Safety Authority are in general not detailed and prescriptive and hence permit plant-specific ETCs if they are sufficiently justified and based on proper material and plant conditions. This paper describes the bases for the ETCs and an ongoing work to revise the ETCs to enable the use of a material-specific master curve for crack initiation, KIC, with compliance with the reactor vessel integrity analyses.
Use of Embrittlement Trend Curves for RPV Integrity Evaluation According to VERLIFE
Authors: Brumovský Milan
Published: June 2023

This paper explains the procedure for evaluating RPV material degradation in WWER-type reactors during operation. Because no legal document existed in the former Soviet/Russian codes and rules, the VERLIFE project within the European research activities started with the aim of elaborating such a document, which had to be consistent with the original Soviet/Russian codes and rules and incorporate PWR approaches and the most current developments in fracture mechanics. This document was finalized as IAEA-NULIFE-VERLIFE “Procedure for Evaluation of Integrity and Lifetime of Components and Piping in WWER NPPs during Operation” with participation of experts from all countries operating WWERs, as well as some countries in the European Union. This procedure has been accepted as Section IV in the normative technical documentation of the Czech Association of Mechanical Engineers and is continuously updated.
Development of Modern Dose-Damage Relations in the United Kingdom
Authors: Tuck Oliva , Pyke Caroline , Styman Paul , Ortner Susan
Published: June 2023

Current models for predicting the embrittlement of reactor pressure vessels are often developed on data derived from a single country in order to suit that country's requirements. Such models tend to predict data from a reactor fleet operating in another country more poorly. Previous investigations have found a possible correlation with initial yield stress. This investigation looks at the possibility of general improvements to models by the better use of data and incorporating yield stress in the predictive modeling. Previous models predict embrittlement from Charpy transition temperature shifts alone. This is an inefficient use of the underlying data and disproportionately propagates errors in the beginning-of-life transition temperature to all subsequent measurements. In this work we utilize all of the Charpy impact measurements. Three linear models have been developed to describe the upper shelf energy (USE), the temperature at the midpoint of the Charpy curve (tmid), and the inverse slope at tmid, S, in steels with less than 0.1% copper. These are then combined to predict full Charpy curves. The models produced good predictions of the USE and tmid but a poorer prediction of the S parameter; further optimization of this model is required in the future. When the three models were combined to predict full Charpy curves they gave reasonable predictions, indicating that this approach is viable. Charpy curves from different countries were predicted similarly well, suggesting that (i) this approach may better capture the influence of material and environmental variables on embrittlement and (ii) the yield stress is an important predictor variable.
Perspective on Trend Curve Models and Their Role in RPV Integrity
Authors: Soneda Naoki , Kirk Mark
Published: June 2023

The use of nuclear energy is critical for achieving carbon neutrality in 2050 and beyond as well as energy security worldwide. For this, the safe operation of nuclear power plants must be guaranteed. Material aging issues of safety-significant components are of primary concern, and particularly the neutron irradiation embrittlement of reactor pressure vessels (RPVs) must be appropriately evaluated and managed to protect RPVs from failure during normal operation as well as postulated accident conditions. The amount of embrittlement is estimated using embrittlement trend curves (ETCs), and thus the accuracy and reliability of the ETCs are critical for the continued operating safety of RPVs. In this paper, we discuss how the reliable prediction of RPV embrittlement using ETCs can be enabled. The role and history of ETCs are briefly summarized followed by three topics on ETCs from the viewpoints of accuracy, margin, and database.
Chemical Composition Effect on Radiation Embrittlement and Hardening of WWER-1000 RPV Steels
Authors: Zarazovskii Maksym , Revka Volodymyr , Chyrko Liudmyla
Published: June 2023

This paper briefly describes the material characterization of the WWER-1000 RPVs that operate in Ukraine and the RPV material degradation monitoring program using surveillance specimens. The research is aimed at the surveillance database collection for the following characteristics of the WWER-1000 RPV beltline welds—transition temperature, yield stress, and master-curve reference temperature—followed by statistical treatment and analysis of these databases. This paper publishes yield stress and master-curve reference temperature data for the first time. The main goal of the paper is the identification of the chemical factor influence on radiation embrittlement and radiation hardening for welds from the RPV core region. It is found that silicon and nickel have the greatest impact on the transition temperature shift. The yield stress shift and master-curve reference temperature shift are most affected by nickel, silicon, and chromium. It is also shown that nickel and manganese have a synergetic effect for both radiation embrittlement and hardening. Based on the results of the statistical analysis a simple general form for the embrittlement trend equations for the transition temperature and master-curve reference temperature as well as hardening are proposed.
Neurophysiological Evidence for Semantic Processing of Irrelevant Speech and Own-Name Detection in a Virtual Café
Authors: Brown Adi , Pinto Danna , Burgart Ksenia , Zvilichovsky Yair , Zion-Golumbic Elana
Published: June 2023

The well-known “cocktail party effect” refers to incidental detection of salient words, such as one's own-name, in supposedly unattended speech. However, empirical investigation of the prevalence of this phenomenon and the underlying mechanisms has been limited to extremely artificial contexts and has yielded conflicting results. We introduce a novel empirical approach for revisiting this effect under highly ecological conditions, by immersing participants in a multisensory Virtual Café and using realistic stimuli and tasks. Participants (32 female, 18 male) listened to conversational speech from a character at their table, while a barista in the back of the café called out food orders. Unbeknownst to them, the barista sometimes called orders containing either their own-name or words that created semantic violations. We assessed the neurophysiological response-profile to these two probes in the task-irrelevant barista stream by measuring participants' brain activity (EEG), galvanic skin response and overt gaze-shifts.

SIGNIFICANCE STATEMENTWe found distinct neural and physiological responses to participants' own-name and semantic violations, indicating their incidental semantic processing despite being task-irrelevant. Interestingly, these responses were covert in nature and gaze-patterns were not associated with word-detection responses. This study emphasizes the nonexclusive nature of attention in multimodal ecological environments and demonstrates the brain's capacity to extract linguistic information from additional sources outside the primary focus of attention.
PARK15/FBXO7 is dispensable for PINK1/Parkin mitophagy in iNeurons and HeLa cell systems
Authors: Kraus Felix , Goodall Ellen A , Smith Ian R , Jiang Yizhi , Paoli Julia C , Adolf Frank , Zhang Jiuchun , Paulo Joao A , Schulman Brenda A , Harper J Wade
Published: June 2023

The protein kinase PINK1 and ubiquitin ligase Parkin promote removal of damaged mitochondria via a feed‐forward mechanism involving ubiquitin (Ub) phosphorylation (pUb), Parkin activation, and ubiquitylation of mitochondrial outer membrane proteins to support the recruitment of mitophagy receptors. The ubiquitin ligase substrate receptor FBXO7/PARK15 is mutated in an early‐onset parkinsonian–pyramidal syndrome. Previous studies have proposed a role for FBXO7 in promoting Parkin‐dependent mitophagy. Here, we systematically examine the involvement of FBXO7 in depolarization and mtUPR‐dependent mitophagy in the well‐established HeLa and induced‐neurons cell systems. We find that FBXO7−/− cells have no demonstrable defect in: (i) kinetics of pUb accumulation, (ii) pUb puncta on mitochondria by super‐resolution imaging, (iii) recruitment of Parkin and autophagy machinery to damaged mitochondria, (iv) mitophagic flux, and (v) mitochondrial clearance as quantified by global proteomics. Moreover, global proteomics of neurogenesis in the absence of FBXO7 reveals no obvious alterations in mitochondria or other organelles. These results argue against a general role for FBXO7 in Parkin‐dependent mitophagy and point to the need for additional studies to define how FBXO7 mutations promote parkinsonian–pyramidal syndrome.
Recent findings and the energetic potential of plant biomass as a renewable source of biofuels - A review
Authors: Ioelovich Michael
Published: June 2023

Nowadays the main sources of energy are petroleum, coal, and natural gas. However, these fossil sources are not reproduced in nature; on a human timescale their reserves are exhausted permanently and run down. Considerable attention in recent years has been given to plant biomass, which in contrast to the fossil sources is continuously renewed in nature. In this critical review the use of non-edible plant biomass for production of various kinds of biofuels is considered. To generate energy, plant biomass either can be burned directly or it can be used after its conversion into carbonized solid fuel (e.g. biochar), liquid fuels (bioethanol, biodiesel, bio-oil), or gases (biogas). Among various biofuels, production of bioethanol has potential to be the most attractive if recent technological advances become implemented, such that the co-production of ethanol and valuable byproducts can be combined together with recycling of solid and liquid wastes. A comparative analysis of energetic potential of biomass and various kinds of biofuels revealed that the most efficient way to produce energy is by direct burning of the plant biomass in a pelletized form, while the burning of such amount of the solid, liquid, or gaseous biofuel, which can be obtained from the plant material, gives a much smaller energetic effect. Novel types of pellets, as well as solid/liquid biofuels, having improved fuel characteristics are described.
Optimization of panel furniture plates rework based on intelligent manufacturing
Authors: Luo Yiran , Xu Wei
Published: June 2023

Panel furniture uses an intelligent management system, combined with the production method of splitting orders by process, to achieve large quantities and large-scale manufacturing, but because of the insufficient and incomplete use of technology, capacity bottlenecks still exist. The problem of rework and replenishment is a long-term problem in furniture production. Under the constraints of existing production rules, the time difference of plates rework forces the original batch of plates to wait, which reduces the efficiency of warehousing. From the perspective of intelligent manufacturing for the optimization of the plates rework process, this study, through on-site observation records and data analysis of the production system, aimed to find short-term solutions and long-term solutions. In the short-term response, the time node for the completion of the replenishment is mainly according to the process regulations, and the plates are packaged into the warehouse after the replenishment is completed in batches. The long-term response strategy is mainly to achieve the interconnection of different production systems to achieve mutual information, and the paperless online operation of the plates rework process increases the subjective initiative of each process to improve the overall efficiency of the plates rework process.
Speaker stance and engagement across disciplines in Lithuanian university lectures: the case of mes ‘we’ in medicine and business administration
Authors: Maslauskienė Greta
Published: June 2023

To gain a greater understanding of how speakers construct their disciplinary-situated identities and interact with their addressee(s) in Lithuanian spoken academic discourse, this corpus-based exploratory analysis focuses on the use of mes ‘we’ as a marker of stance and engagement in lecturers’ speech in Lithuanian university lectures on business administration and medicine. The data reveals that the lecturers in business administration used only the inclusive mes ‘we’, which is known to promote student involvement and strengthen lecturer-student rapport. The instructors in medicine frequently employed the exclusive reference to indicate their belonging to professional communities and highlight their level of expertise in the discipline, creating a sense of distance between the lecturer and the student audience.
Seasonal dynamics of algal flora of Lake Zasvitske (Rivne region, Ukraine)
Authors:   Rivne State University Humanities, 12, Stepana Bandery Str., Rivne 33028, Ukraine, Sukhodolska I.L. , Basaraba I.V. ,   Rivne State University Humanities, 12, Stepana Bandery Str., Rivne 33028, Ukraine
Published: June 2023

The study deals with the algal flora of Lake Zasvitske (Rivne region, Ukraine). They belong to 8 divisions, 13 classes, 24 orders, 34 families and 51 genera. Totally 61 species of algae (62 intraspecies taxa) were identifiedhe. It was shown that Bacillariophyta, Chlorophyta, Cyanobacteria and Streptophyta play the significant role in lake phytoplankton development. According to the population Shannon diversity index varies from 2.13 bit/spec. (October) to 3.89 bit/spec. (July), and according to biomass this index varies from 1.63 bit/spec. (June) tо 4.10 bit/spec. (July). In the lake phytoplankton poly-dominant structure prevails. In Lake Zasvitske the phytoplankton core is developed with planktonic-benthic and planktonic species, slow-flowing species according to water saturation with oxygen and rheophilicity, indifferent species in relation to the density, pH level of the environment and water temperature, mesoeutrophic ones and species with wide amplitude according to the trophic level. Eurysaprobes (according to the Watanabe system) and beta-mesosaprobionts (according to the Pantle-Buk system as modified by Sladechek are predominant among indicator species of organic water pollution.
Ensuring balanced social and labor development of Ukraine: challenges and opportunities
Authors:   Institute of Industrial Economics of the NAS of Ukraine, Novikova Olga , Ostafychuk Yaroslav ,   Institute of Industrial Economics of the NAS of Ukraine
Published: June 2023

The post-war revival of Ukraine will be determined by a set of parameters, among which an important place belongs to the social and labor sphere. A fair balance of rights and real opportunities of employers and employees should ensure the effectiveness of channels of social mobility, accumulation of human and social capital. The purpose of the article is to determine the requirements and substantiate the possibilities for ensuring labor development on the basis of balance and stability in the conditions of the post-war development of Ukraine. Social and labor development is interpreted as a process of transformation and adaptation of institutions of the social and labor sphere, its subjects, as well as social and labor relations between them and with other interested parties, as a result of which qualities adequate to the challenges of the external and internal environment are acquired. It was established that the current state policy in the field of labor in Ukraine is based on the ideology of neoliberalism, mainly reflects the interests of employers and significantly limits the rights of employees, which increases the risks of destroying established institutions of social and labor relations, and has negative social consequences. The need to orientate state policy on the principles of decent work, the concept of which should be expanded taking into account new processes and phenomena arising in the social and labor sphere under the influence of digitalization, is argued. It was emphasized that the post-war social and labor sphere should have the potential of stability, adaptation and functioning in the conditions of renewed military conflict. It was concluded that the existing models of ensuring national stability can acquire new qualities, taking into account the achievements of interdisciplinary research on the issue of resilience, which pay special attention to socio-behavioral factors of the development of socio-economic systems. Scientific approaches to the interpretation of resilience have been analyzed, and a range of problems requiring further research has been identified.
ABERRANT EXPRESSION OF COL14A1, CELRS3, and CTHRC1 IN BREAST CANCER СELLS
Authors: Malvia Shreshtha , Chintamani Chintamani , Sarin Ramesh , Dubey Uma S , Saxena Sunita , Bagadi Sarangadhara Appala Raju
Published: June 2023

Background: Collagens, which are the major components of the extracellular matrix involved in the regulation of tumor microenvironment, could be differentially expressed in breast cancer (BC) with different transcriptome profiling. Aim: To analyze the transcript level expression of COL1A1, COL5A1, COL10A1, COL11A1, COL12A1, COL14A1, CTHRC1, and CELRS3 genes and the clinical relevance of their differential expression in BC. Materials and Methods: The transcript level expression of the genes was analyzed using the quantitative real-time PCR (qPCR) in tumor tissue of 60 BC patients. Results: Overexpression of COL1A1, COL5A1, COL10A1, COL11A1, COL12A1, CTHRC, and CELRS3 anddown-regulated expression of COL14A1 were observed. COL14A1 down-regulation was associated with aggressive, basal, and Her-2/neu BC subtypes (p = 0.031). Overexpression of CELSR3 was found to be associated with the older age of the patients (> 55 years, p = 0.049). Further analysis with the TCGA BC data set has shown a concordance in the differential expression of the above genes. Furthermore, overexpression of CTHRC1 was associated with poor overall survival (OS), particularly with poor prognosis (p = 0.00042) for the luminal BC subtype. On the other hand, CELSR3 overexpression was associated with mucinous tumors and poor prognosis in post-menopausal women. In silicotarget prediction identified several BC-associated miRNAs and members of miR-154, -515, and -10 families to perform a likely regulatory role in the above ECM genes. Conclusion: The present study shows that the expression of COL14A1 and CTHRC1 may serve as potential biological markers for the detection of basal BC and the prognosis of survival for patients with the luminal subtype of BC.
Reliability and safety of launch complexes
Authors:   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Poshyvalov V.P. , Daniiev Yu.F. ,   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine
Published: June 2023

This paper is concerned with the reliability and safety of launch complexes. The problems to be solved in launch complex reliability evaluation are identified: calculations of the probability of no-failure operation of passive redundancy systems with equal- and nonequal-reliability elements, reliability analysis for replacement redundancy with integer multiplicity and unloaded reserve; calculations of the probability of no-failure operation of the launch complex components in launch preparation, and calculations of the reliability indices of a component part as a whole and a comparison of the calculated reliability indices with the specification requirements. Since a launch complex consists both of renewable elements and of nonrenewable ones, the reliability indices must be calculated so that one may evaluate the reliability both of individual elements and of a system of different-type elements as a whole. These indices are characterized by the nonfailure operation time and recovery time distributions and show the probability of а serviceable state or a failure state of an element and a system. On condition that the nonfailure operation time and the recovery time can be described by the Weibull distribution, expressions are obtained for the availability factor, i.e., the probability of the launch complex being operative at an arbitrary time, except for scheduled periods during which the launch complex is not envisaged for use. Launch complex safety is evaluated by the probability of hazards, the identification of main ways to mitigate their consequences, and account for weight of the consequences of possible hazards in service. Launch complex safety indices are identified. It is shown that safety must be evaluated using indices suitable for the practical solution of problems of the justification and assurance of specified safety requirements against possible threats in the development of launch complexes. The adopted safety index is the probability that each hazard that occurs in a certain time will be eliminated. A renewal process is used to describe a random number of hazard occurrences. To determine the hazard frequency, it is recommended to use statistical data on launch complex accident rate and reliability, logical methods of event tree and fault tree analysis, accident simulation models, and expert judgments.
System approach to the organization of information support for a launch vehi-cle’s active control system driven by the current operating conditions
Authors:   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Gorbuntsov V.V. , Zavoloka O.M. ,   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine
Published: June 2023

The goal of this paper is to develop elements of a simulation algorithm for determining the controlled dynamic parameters of the sustainer stages of launch vehicles (LVs) equipped with an active control system (ACS). In this study, methods of system analysis and computational rocket dynamics were used. The paper proposes a system approach to the organization of LV ACS information support with account for specified limiting values of the controlled dynamic parameters: the pitch rate, the velocity pressure, and the angle of attack. In flight, the LV ACS uses information on these parameters to suppress bending deformations of the LV structure and form a trajectory close to the energy-optimal one. The controlled dynamic parameters were brought to a simplified form, thus making it possible to take the data needed for their calculation from the inertial sensors of the LV control system. Simulation algorithm elements were developed to determine the dynamic parameters from the actual values of the center of mass motion parameters in the launch coordinate system, which can be obtained from their calculated values and the corresponding isochronous variations of their apparent values in the inertial coordinate system. The elements of the simulation algorithm for the determination of the LV sustainer stage dynamic parameters may be used in the development of ACS methodological support. The main advantage of the proposed system approach with account for specified limiting values of the controlled dynamic parameters is that it does not require any detailed simulation of dynamic loads on the LV sustainer stages and uses nothing but information on the dynamic parameters that characterize LV trajectory motion conditions.
Effect of the tip geometry of a truncated supersonic nozzle on its characteristics
Authors:   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Ternova K.V.
Published: June 2023

Truncated nozzles are used for tight packing of the rocket engine. Such nozzles have a profiled tip to maximize the filling of space and reduce the overall weight. This paper is concerned with the study the effect of the tip geometry of a truncated supersonic nozzle on its characteristics. The features of the gas flow at different initial pressures and different environmental conditions in the supersonic area of a nozzle with a bell-shaped tip of different lengths are considered. The flow inside the nozzle followed by the jet outflow into the surrounding space was simulated. The flow simulation for tips at sea level showed a similar structure of the Mach number isolines, and the only difference was in the intensity of the vortex structure near the tip wall. As the pressure at the nozzle inlet increases, the length of the first “barrel” increases proportionally, and the vortex structure near the tip walls decreases. For the upper atmosphere, the flow pattern is different. The supersonic flow in the nozzle does not undergo separation, and therefore there are no vortex structures from the external environment. The flow downstream of the tip exit deflects from the axis through the angle determined by the Prandtl–Meier flow at the corner point of the tip exit, and the shape of the first “barrel” is distorted by a hanging shock. An analysis of the obtained results shows that the ambient pressure downstream the nozzle exit significantly affects the flow pattern in the nozzle. It is established that the thrust coefficient of both circuits at sea level decreases with increasing pressure at the nozzle inlet, which is explained by a decrease in the effect of the ambient pressure on the tip wall. In the upper atmosphere, the flow is adjacent to the tip wall, and the thrust coefficient for nozzles of different lengths has almost the same constant value at different inlet pressures. It is shown that a decrease in the length of the nozzle, all other geometrical dimensions of the nozzle being equal, does not significantly affect the impulse characteristics.
Determination of the force exerted by an ion beam on a space debris object from the edges of its images using deep learning
Authors:   Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Redka M.O.
Published: June 2023

The goal of this article is to develop an effective image preprocessing algorithm and a neural network model for determining the force to be transmitted to a space debris object (SDO) for its non-contact deorbit. In the development and study of the algorithm, use was made of methods of theoretical mechanics, machine learning, computer vision, and computer simulation. The force is determined using a photo taken by an onboard camera. To increase the efficiency of the neural network, an algorithm was developed for feature recognition by the SDO edge in the photo. The algorithm, on the one hand, selects a sufficient number of features to describe the properties of the figure and, on the other hand, significantly reduces the amount of data at the neural network input. A dataset with the features and corresponding reference force values was created for model training. A neural network model was developed to determine the force to be exerted on a SDO from the SDO features. The model was tested using a set of eighteen calculated cases to determine the effectiveness, accuracy, and speed of the algorithm. The proposed algorithm was compared with two existing ones: the method of central projections onto an auxiliary plane and the multilayered neural network model that calculates the force using the SDO orientation parameters. The comparison was performed using the root mean square error, the maximum absolute error, and the maximum relative error. The test results are presented as tables and graphs. The proposed approach makes it possible to develop a system of SDO non-contact removal that does not need to determine the exact relative position and orientation with respect to the active spacecraft. Instead, the algorithm uses camera-taken photos, from which the features necessary for calculation are extracted. This makes it possible to reduce the requirements for its computing elements, to abandon sensors for determining the relative position and orientation, and to reduce the cost of the system.
Populist orientations in Ukrainian society: origins and characteristics of reproduction
Authors: Reznik Oleksandr
Published: June 2023

Populist orientations refer to a set of political beliefs and values that emphasize the interests of «ordinary people» with a corresponding need to challenge the political establishment. In Ukraine, long social transformations in the post-communist period led to total mistrust and a negative attitude toward state institutions. The post-communist irremovability of the political establishment led to persistent anti-elitist attitudes. As a result of the inconsistency and contradictions of Ukraine's path to democracy, a basic «transitional type» of personality has emerged. It is characterized by psychological ambivalence, that is a double contradictory attitude to the prospects of society's development. The connection of ambivalent consciousness with populist orientations often arises because both phenomena are based on the absence of a stable ideological orientation or a clear political identity. The ambivalent consciousness and unbelief in the pluralist mechanisms of an imperfect democracy have fuelled the population's attachment authoritarian methods in politics, which is a reflection of the hopes for effective governance. However, the existence of polarization in Ukrainian society based on geopolitical orientations and social identities for a long time conditioned citizens to rely on traditional political forces in their electoral behavior. Only after the disappearance of this polarization did populist orientations materialize into the electoral phenomenon of 2019. In the course of the full-scale Russian-Ukrainian war, a radical reassessment of the state and state institutions by the population took place, and therefore the antagonism between the population and the elite became temporarily irrelevant. However, post-war reconstruction carries with it the risks of a revival and growth of populist orientations, as economic difficulties will exacerbate intolerant of social injustice.
Faces of the phenomenon of expectations
Authors: Shulga Mykola
Published: June 2023

The article examines the vision of the phenomenon of expectations in the works of sociologists. For this purpose, an analysis of the works of M. Weber, T. Parsons, A. Schutz, V. Vroom, H. Heckhausen, N. Luhmann, P. Berger, Th. Luckmann, Y. Habermas, Z. Bauman, I. Hoffman, H. Garfinkel. The study showed that expectation is a complex and diverse phenomenon that cannot be reduced to a single denominator. The traditional method of organizing this colorful phenomenon by means of selection according to one or more criteria of classes and types of expectations has its limitations. After all, classification as a method of explanation can be the cause of false conclusions and interpretations, since the same manifestations of expectations can hide different reasons for their occurrence. K. Levin called this way of theorizing Aristotelian. The scientist saw a way out of this situation in the transition to the Galilean way of thinking. K. Levin called this transition the transition from the abstract-classifying to the constructive method. The latter means searching for the reasons for the existence of natural and social phenomena. This way of thinking is demonstrated in the works of the above-mentioned sociologists. Thanks to the analysis of their works, it was possible to distinguish four types of expectations. The first is pre-intentional expectations, the second is rational-activity expectations, the third is communicative-role expectations, and the fourth is background expectations. The essence of the pre-intentional type consists in unlimited dreams, fantasies, illusions, imaginations, which are concentrated in the consciousness of the subject of expectations, and which have no influence on the external world. The rational-activity type is an anticipatory reflection of object-transforming activity, processes of acquisition or appropriation of objects, which takes the form of intentions, plans, calculations, and the purpose of activity. The communicative-role type is manifested in the observance by interaction partners of standardized norms, rules, requirements, in the reproduction of status and role standards in behavior. The essence of background expectations lies in the presence of fixed attitudes in the behavior of the individual, in the standardized features of everyday processes, which are accepted by a person in everyday life on faith.
The impact of the COVID-19 pandemic on people with disabilities: Perspectives from people with disabilities
Authors: Sharapov Kirill , Anderson David , Burova Olga , Nazarenko Viktoria , Polishchuk Olena
Published: June 2023

In this paper, we relied on co-researching with persons with disabilities in Ukraine not as a means of understanding the epidemiology of this disease, or of its impact on human health. We approached COVID-19 and the Ukrainian authorities’ response to the pandemic as proxy, or a magnifying glass, to better understand the everyday life of persons with disabilities in Ukraine, and to explore how things could and should be done differently in the context of public health or other emergencies. The pandemic unsettled and disrupted the meanings of personal space and time for virtually everyone across the world; it unmasked, reinforced and reconfigured existing inequalities, cascading them into further injustices of (im)mobility and access. This is especially true for persons with disabilities. Kennedy-Macfoy uses an analogy in relation to COVID-19. She describes COVID-19 as a ‘looking glass’. Our ‘COVID-19 as a looking glass’ findings presented in both parts of the project report paint a picture of entrenched economic and social deprivations experienced by people with disabilities in Ukraine, patterned by the intersecting and reinforcing inequalities of gender, age, locality, displacement, and socio-economic status, and exacerbated rather than created by the pandemic. This article is devoted to the second part of the extensive study ‘The Impact of the COVID-19 Pandemic on People with Disabilities in Ukraine’. In this article, the authors elaborate on the methodology of the second phase of the study and the views of people with disabilities on the issues of communication about the COVID pandemic and access to medical care during a pandemic for people with disabilities.
CALCULATION OF DC CONVERTERS IN DISCONTINUOUS CONDUCTION MODE USING THE AVERAGING METHOD BASED ON LAGRANGE THEOREM
Authors:   Institute of Electrodynamics National Academy of Sciences of Ukraine, pr. Peremohy, 56, Kyiv, 03057, Ukraine, Rudenko Yu.V.
Published: June 2023

The features of calculation of output voltage ripple in dc converters with discontinuous conduction modes are considered. It is shown that the use of behaviors of charge-discharge processes of the output capacitor makes it possible to determine the parameters of voltage pulsation on it, using a mathematical model of the converter with variables averaged using Lagrange's theorems. The specified approach contributes to the significant simplification of calculations and reduction of their labor intensity. Analytical and graphical dependences of the ripple value and the ripple coefficient of output voltage of main circuits of the converters in the mode of discontinuous conduction - buck, boost and buck-boost types - were obtained. The developed analytical dependencies make it possible to effectively calculate the parameters of the converters and investigate their properties at the stage of their design, using available methods of mathematical analysis. The reliability of the obtained analytical ratios and calculation results was confirmed by simulation of converters using the PSim package. References 14, figures 4, tables 3.
THE FEATURES OF COMMUTATING PROCESSES IN A THREE-PHASE BRIDGE COMPENSATION CONVERTER
Authors:   National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», 37, Peremohy Ave., Kyiv, 03056, Ukraine, Boiko V.S. , Shkardun O.V. ,   National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», 37, Peremohy Ave., Kyiv, 03056, Ukraine
Published: June 2023

Electromagnetic processes are investigated in two versions of a three-phase bridge converter with improved energy characteristics, one of which contains one switching link, and the other two. The commutating link consists of a three-phase capacitor battery and a three-phase group of fully controlled devices. This technical solution makes it possible to ensure the recharging of the capacitors of the commutating link and the control of the energy process of the converter. The main content of the study is the analysis of electromagnetic processes in terms of the features of commutating processes and the proof of the energy capabilities of the options for implementing the converter. The amount of scientific research required for this is divided into three options. Each takes into account the peculiarities of electromagnetic processes associated with different modes of operation of converters, at different frequencies of control pulses of transistors of a commutating link and a shift in the moment of switching on transistors relative to the interval of operation of power electric diodes. As a result, a generalized mathematical model was created. She describes a variety of electromagnetic processes in converters, allows you to calculate the commutating and adjustment angles. They are the main characteristics of the energy process and prove that the developed versions of the converter are compensation. They are able not only to compensate for their own reactive energy, but also, if necessary, to generate reactive energy to the grid. References 12, figures 2, table 1.
ANALYSIS OF ELECTROMAGNETIC PROCESSES IN THE "VOLTAGE LIMITER - LOW-FREQUENCY FILTER" CIRCUIT DURING THE INFLUENCE OF HIGH-VOLTAGE SURGE FROM THE POWER SUPPLY NETWORK
Authors:   Institute of Electrodynamics National Academy of Sciences of Ukraine, pr. Peremohy, 56, Kyiv, 03057, Ukraine, Pavlovskyi V.O. , Gurin V.K. ,   Institute of Electrodynamics National Academy of Sciences of Ukraine, pr. Peremohy, 56, Kyiv, 03057, Ukraine, Yurchenko O.M. ,   Institute of Electrodynamics National Academy of Sciences of Ukraine, pr. Peremohy, 56, Kyiv, 03057, Ukraine
Published: June 2023

In the work, a theoretical analysis of high-voltage surge (HVS) passing from a power supply network through the path "voltage limiter - low-pass filter" is carried out, with the aim to evaluate the effectiveness of the filter on reducing the amplitude of the residual HVS at the input of electrical and/or radio-electronic equipment. As a low-pass filter (LPF), an L-shaped filter was chosen. Typical means of limiting the amplitude of the HVS (gas-filled arresters, varistors, and suppressors) are analyzed, and their shortcomings are shown. The justification of the equivalent scheme for theoretical analysis is given. The analysis revealed a direct relationship between the cut-off frequency of the LPF, which is deter-mined by the nominal values of its elements, and the amplitude of the residual HVS at the mains input of the equipment, and also showed the effectiveness of inserting the LPF between the output of a typical HVS voltage limiter and the mains input of the mentioned equipment from the point of view of additional reduction of the residual HVS amplitude. References 18, figures 6.