NPO Energomash (Russia)

Geothermal scaling is a prevalent issue that significantly impacts the efficiency of thermal energy production, drawing considerable attention in the field. Scaling formation is attributed to multiple factors, including variations in pressure and temperature. In this field, scaling deposits have been associated with an observed production decline of approximately 3.2%, posing a substantial challenge to maintaining optimal operational efficiency. This study aims to quantitatively assess the potential for calcite scaling in selected production wells and to estimate scaling growth rates as a basis for determining appropriate well-cleaning intervals. Geochemical data from produced fluids were analyzed to evaluate calcite and silica saturation using saturation indices derived from simplified thermodynamic relationships. Calcite scaling potential was assessed using the Calcite Saturation Index (CSI), while silica scaling was evaluated using the Silica Saturation Index (SSI). The growth rate of calcite deposits was estimated using a kinetic-based Calcite Scaling Thickness (CST) approach. The results indicate that one production well exhibits calcite supersaturation, while silica scaling is not expected under the analyzed conditions. Based on the applied assumptions, the estimated calcite scaling growth rate suggests that periodic well-cleaning interventions are required to maintain production performance. However, the calculations rely on simplified geochemical assumptions, including the use of concentration-based approximations and empirical kinetic parameters. Therefore, the results should be interpreted as an operational estimate rather than a definitive prediction, and further validation using activity-based geochemical modeling and direct scale characterization is recommended. This study provides an operationally oriented framework for linking geochemical indicators to well-maintenance planning in vapour-dominated geothermal fields.

Jedan od najvažnijih zadataka hidrologije jeste pouzdana procena uticaja klimatskih promena na vodne resurse. Ove analize se zasnivaju na klimatskim projekcijama, koje predstavljaju ulazne podatke za hidrološke modele. Uticaj klimatskih promena se kvantifikuje poređenjem budućih vrednosti hidroloških veličina, i njihovih vrednosti u referentnom (istorijskom) periodu. Jedna od najznačajnijih veličina u ovim analizama je unutargodišnja raspodela protoka koja pokazuje sezonske varijacije oticaja na slivu. Iako predstavlja jedan od najznačajnijih hidroloških potpisa, efikasnost modela u reprodukovanju unutargodišnje raspodele protoka se veoma retko razmatra u inženjerskoj praksi. U ovom radu je hidrološki model sliva reke Ribnice kalibrisan prema nekoliko kriterijumskih funkcija, čime je kreirano nekoliko njegovih verzija. Svaka verzija modela je detaljno analizirana sa aspekta mogućnosti da reprodukuje unutargodišnju raspodelu protoka. Rezultati pokazuju velike varijacije u efikasnosti modela, ali i da verzije modela koje su kalibrisane prema kompozitnim kriterijumskim funkcijama imaju najbolje slaganje sa unutargodišnjim raspodelama osmotrenih protoka. Rezultati takođe pokazuju da ni jedan pokazatelj (odnosno, kriterijumska funkcija u kalibraciji modela) ne odražava u potpunosti različite aspekte efikasnosti modela. Stoga je odabir kriterijumske funkcije veoma važan korak u izradi hidrološkog modela, i treba da se rukovodi konačnom namenom modela (eng. fitness for a said purpose, [1]).

The article presents the results of the extraction of zirconium from high-level waste and spent nuclear fuel cladding. Zirconium is a promising metal that is widely used in various industrial fields, including the nuclear industry.

Acoustic logs have been very important for petrophysical, geophysical and geomechanical modeling and interpretation in the oil and gas industry. Logging while drilling (LWD) acoustic technology has been developed to address the need for rig time saving and real-time applications. Quadrupole acoustic measurement has been developed to obtain the shear wave slowness in the LWD slow formation environment. However, the quadrupole waves are dispersive and guided waves. Consequently, it is difficult to apply a dispersion correction in the shear wave to better represent a formation properly. This paper presents the results of processing the LWD shear wave slowness from quadrupole measured in slow formations and apply a novel dispersion correction. This LWD processed and corrected shear wave is compared with the shear wave obtained from dipole wireline data, defining intervals with the best and poor correlation.

Sodium-ion batteries (SIBs) are gaining attention as a cost-effective and abundant alternative to lithium-ion batteries (LIBs). Despite these advantages, concerns about the thermal safety of SIBs remain, with limited studies addressing this critical aspect. To fill this gap, we present a comprehensive investigation into the thermal runaway dynamics of NVPF (sodium vanadium phosphate fluoride)/hard carbon 18650 sodium-ion batteries using advanced characterization techniques. Notably, we employ high-speed synchrotron X-ray radiography to provide real-time visualization of internal processes and reactions during thermal runaway, offering insights into the battery’s behavior under extreme conditions. Complementary gas analysis techniques are utilized to explore thermal characteristics, gas composition, emitted volumes, and energy aspects associated with thermal runaway, providing an understanding of the events leading to and during thermal runaway. Comparative analyses with lithium iron phosphate (LFP) and nickel manganese cobalt (NCM) LIBs reveal that SIBs exhibit thermal safety performance comparable to that of LFP LIBs and superior to that of NCM LIBs. This study aims to contribute to the improvement of our understanding of SIB safety and to offer some useful insights for the development of safer sodium-ion battery technologies.

Abstract Well intervention operations are essential for maintaining and enhancing the productivity of oil and gas wells. This paper discusses hazard management framework that integrates techniques to enhance safety and efficiency at worksites during Well intervention campaign – Closed-In Well Restoration (CIWR) – operations. The paper Illustrates the application of proactive measures including contractor pre-mobilization and engagements that created desired alignment and delivery of HSE expectations as well as an enhanced Safe Systems of Work (SSoW) and adaptive Permit to Work protocols that delivered over 200,000 man-hours of intense sitework over a period of 8 months without an LTI. The campaign employed the use of several Contractors rendering various wells and subsurface services – wellhead maintenance, slickline, electric line, coiled tubing for pumping and stimulation, etc. The result highlights improvements in operational safety, reduced downtime, and increased compliance with industry standards and regulatory requirements. This paper emphasizes the critical role of proactive engagement for alignment and effective monitoring as a transformative approach to hazard management, offering practical insights for operators seeking to advance safety culture and operational excellence in intervention activities.

The object of study is the evolution of Soviet historiography and the main driving factors during the specified chronological period, while the subject is the scientific contribution of domestic historians to the understanding of the processes of collectivization and "dekulakization" in the western regions of the USSR. The aim is to identify the key factors in the development of Soviet historiography on this topic, as well as their impact on the content of research and the scientific achievements of Soviet historians. The author examines in detail the evolution of themes and assessments compared to the preceding period, as well as the contradictions in the evaluations of collectivization and the statistics on the maturation of preconditions and the pace of collectivization in Western regions and republics. Special attention in the article is given to the specific factors influencing the development of historiography on post-war collectivization, under-researched topics, and the reasons for the persistence of little-explored issues. The analysis of Soviet historiography of post-war collectivization employs methods of periodization and a genetic approach to determine the nature of changes in historiographical positions and assess the degree of their influence; a systemic comparative analysis is used to compare the thematic development of research; as well as a problem-chronological method combined with the principle of historicism to structure the obtained results. The scientific novelty is due to a comprehensive study of the dynamics of Soviet historiography on post-war collectivization through the lens of modern concepts of the school of V. P. Danilov, which studied the collectivization of the 1930s. The author draws several conclusions. During the examined period, a significant number of documents were published, expanding the source base. Within ideological frameworks, Soviet historians were able to study in more detail the preconditions and mass post-war collectivization. Historians differentiated the measures applied to kulaks into economic actions and "dekulakization." For the first time, the number of kulaks by regions and those exiled to the PMSSR was provided, along with cautious critical remarks about the immaturity of the preconditions for collectivization. The methods of kulak resistance were studied in greater detail, and doubts were raised about the necessity of "dekulakization" due to the small number of kulaks in the PMSSR. A special contribution of the article's author is the examination of the specific factors affecting the development of the Soviet historical paradigm based on works about post-war collectivization, highlighting the contradictions in statistics and ideological settings. The results of the research can be applied in the scientific study of the evolution of Soviet historiography, as well as for educational and enlightening purposes.

The sequence of experimental work on determining the oil displacement coefficient by water is presented; it is shown that in the models of the oil displacement coefficient by water obtained as a result of experimental studies, various factors characterizing the filtration-capacity properties of reservoirs, the pore structure of the medium, and the physicochemical properties of reservoir fluids are used. It has been established that models for calculating the oil displacement coefficient by water with high correlation coefficients can be described by various types of dependencies: linear; quadratic; cubic; exponential; logarithmic exponential.

This study aims to evaluate the impact of service quality and digital marketing on consumer loyalty at PT Pos Indonesia, Yogyakarta, with a focus on understanding how customer satisfaction mediates these relationships. The context of this research is particularly relevant in light of the company’s recent decline in market share and its attempts to adapt to a rapidly changing competitive environment in the expedition industry. A quantitative approach with a causal design was employed. Data were collected through an online questionnaire from 155 respondents who had used PT Pos Indonesia's services. Structural Equation Modeling (SEM) using Partial Least Squares (PLS) was used to test the hypotheses and analyze the relationships between service quality, digital marketing, customer satisfaction, and consumer loyalty. The analysis revealed that service quality has a significant positive effect on both customer satisfaction and loyalty. Customer satisfaction was found to mediate the relationship between service quality and loyalty. In contrast, digital marketing showed a negative but near-significant effect on consumer loyalty and had no significant impact on customer satisfaction. The mediating effect of customer satisfaction on the relationship between digital marketing and loyalty was not significant. This study highlights the critical role of service quality in enhancing customer loyalty, both directly and indirectly through customer satisfaction. Companies, particularly PT Pos Indonesia, should focus on improving service quality as it significantly influences consumer loyalty. Digital marketing strategies, however, need reevaluation, as they do not seem to align with customer expectations and have not proven effective in fostering loyalty. The study’s findings suggest that companies should prioritize service quality improvements and adopt a more targeted, customer-oriented digital marketing approach. Future research could expand on these findings by exploring the impact of external factors or conducting comparative analyses with competitors in the expedition industry.

When transporting and storing hydrocarbons, one of the main operational problems is the external and internal corrosive wear of the metal. A frequent cause of accidents in main and technological gas pipelines due to their stress corrosion cracking is the enrichment of the pipe body with hydrogen. Literature experimental data on the effect of hydrogen on the hardness of iron and low-carbon steels during their electrolytic saturation with hydrogen are analyzed. It is noted that the curves of changes in hardness in all the analyzed sources for all these materials have a similar form: at the initial stage of hydrogenation, the hardness increases, reaching its maximum, and then it declines to values close to the initial level follows. At the same time, the time to reach the maximum hardness decreases with the introduction of promoters into the electrolyte solution, which can be Na2S, As. Increasing the current density during electrolysis increases the value of the maximum hardness. The time to reduce the hardness to the initial level is approximately the same as the hydrogenation time required to achieve maximum hardness. Possible explanations of the regularities obtained by the authors are given.