Technology audit and production reserves

Estimation of fuel consumption in standard driving cycles and in real bus operation

Dmytro Ruban — 2025-04-10

The object of research is the basic fuel consumption of a bus in standard urban cycles and identical conditions in real operation.

Standard driving cycles are used to estimate fuel consumption. This allows consumers to compare buses and choose the best one, and manufacturers in the process of improving buses also allow them to estimate fuel consumption. However, sometimes standards may not correspond to reality. Therefore, specific routes are developed for some cities, which requires significant development costs. This problem is solved by collecting reliable information on average fuel consumption with an operating period of 1 year and bus mileage of 40–90 thousand km. As a rule, operating organizations do not provide such information. The development of electronic control systems allows to obtain information from “black boxes” additionally installed by the manufacturer, which record information throughout the entire service life of the bus. This approach is implemented in this work.

Existing standards for determining fuel consumption in urban driving cycles are presented. The results of modeling and real tests are presented. Information was collected from the “black boxes” on fuel consumption on 12 buses for 1 year of operation with mileage from 40 to 90 thousand km on Ataman A092N6 buses. Fuel consumption was 16.4–21.2 l/100 km when operating buses in one city (the manufacturer claims up to 23 l/100 km). This makes it possible to solve the problem of collecting reliable information on fuel consumption based on year-round operation of buses, which has not been carried out in this format before.

The results of this study will allow operating organizations to see the real fuel consumption on Ataman A092N6 buses in the city. Implementation of this approach on other buses will allow obtaining data for interested organizations similarly. This will allow estimating fuel consumption without additional tests, which will reduce research costs.

Determination on energy efficiency in corn grain drying

Oleksandr Gorbenko — 2025-04-07

The object of research is the technological processes of corn grain drying, energy plants. One of the most problematic areas for agricultural producers is providing energy for technological processes of bringing grain material to the indicators of product sales. And during the war and post-war period in Ukraine, this requires non-standard approaches and ways of implementation. Therefore, for operation in autonomous mode, the technology involves the use of biomass, electricity from solar panels and/or a diesel generator to supply the coolant to the grain drying zone. The availability of biomass is ensured by cleaning grain material after harvesting and crop residues.

The study examined the technology of corn grain drying in “Agrotechservice” LLC of the Poltava district of the Poltava region (Ukraine) using the Saphir 2134 modular grain dryer with an improved biomass boiler.

The results of studies of the operation of a grain dryer using different types of fuel (gas, diesel fuel, alternative fuel) showed that the energy consumption for reducing humidity by 1 ton-percent was: for gas – 1.5 m³; for diesel fuel – 1.8 l; for biomass – 3.4 kg. The total cost of drying on a Saphir 2134 grain dryer was obtained, which is 0.205 USD, which is 3.7 times less than when using natural gas and 9.2 times less than when using diesel fuel. This is due to the fact that the proposed technology involves the use of an improved biomass boiler and alternative energy sources. This provides the possibility of obtaining average daily savings using a grain dryer of this model with an improved biomass boiler, which will be about 1.1 thousand USD. Compared to similar corn grain drying processes, these studies have shown the economic feasibility of using biomass as an energy material for the production of thermal energy in the corn grain drying process.

Influence of corrosion of the first circuit elements on the distribution of sediments in the circulation tract of the SMR 160 reactor

Igor Kozlov — 2025-04-15

The object of research is the circulation path of a water-water small modular reactor. The work is aimed at assessing the influence of corrosion intensity on the formation of sediments on the surfaces of the first circuit of the SMR 160 reactor module. The analysis of the circuit structure was performed, the intensity of corrosion destruction and the intensity of sediments on the local sections of the circuit are evaluated. The circulation circuit of vertical architecture, the movement of the coolant in which excites thermal pressure, created by heating in the core and cooling in the steam generator.

The methodology is based on the principle of material balance of the transition of corrosion products into the coolant and their sediment on the circuit surface. To estimate the speed of corrosion the results of complex studies conducted at stations in normal operation and on the physical models of sections of the first circuit in the laboratory were used. Estimation of the speed of sediments is performed according to the ratios that take into account the impact of the concentration of the sedimented substance in the coolant, the thermal load of the site and the consumption of the coolant.

The calculations showed that the main source of iron oxides in the circuit is the surface of the steam generator, causing the average value of their concentration in the final areas, and zirconium oxides come from the surface of the core and retain the concentration close to the average along the entire tract.

The research results showed that the high corrosion stability of the structural materials of the circuit significantly limits the transition and accumulation of corrosion products in the coolant. In turn, low concentrations of corrosion products in the coolant restrain the formation of their sediments on the surfaces of the core and steam generator. The values of the surface density of sediments and their average thickness are estimated.

Analysis of corrosion processes of structural materials and the distribution of their sediments in the circuit allow to predict the level of radiation contamination and to plan the service life of the system.

The presented technique allows to evaluate the effectiveness of the water -chemical regime used.

Mathematical modelling of mixture formation in the combustion chamber of a diesel engine

Oleksandr Zhevzhyk — 2025-04-16

The object of research is the process of fuel mixture formation in a vortex combustion chamber located in the piston of a diesel engine.

Ineffective mixture formation leads to increased specific fuel consumption and harmful emissions into the atmosphere. The research addresses determining the conditions under which complete evaporation of droplets is achieved and the required ratio of the amount of fuel vapor and the available amount of air depending on the piston radius.

A mathematical model was created to describe the behavior of fuel droplets under the influence of aerodynamic forces, heat transfer, and phase transition processes. The calculations determined the radial fuel vapor concentration and air-fuel ratio distribution. The study found that fuel droplets with sizes ranging to 90.7 µm are completely evaporated which contributes to volumetric mixture formation. The model also identified regions where the mixture reaches stoichiometric conditions necessary for autoignition, particularly at a radius of r/Rc=0.22.

This is explained by the rapid evaporation of small droplets, the number of which, as a function of the diameter distribution, is the majority, and their high speeds of movement relative to air and high mass transfer coefficients in the initial spraying area.

The study demonstrates that despite non-uniform fuel vapor distribution, volumetric mixture formation is achieved. The interaction between fuel droplets and the swirling air motion ensures adequate mixing, facilitating complete and efficient fuel combustion.

The results can be applied to optimize diesel engine designs by improving combustion chamber geometry and fuel injection strategies. The model is particularly useful for engines with high-pressure fuel injection systems. The work results contribute to developing more efficient diesel engines that comply with stricter emission regulations.

Determination of the dependence of the filtration properties of a biopolymer system on pressure, temperature and concentration of components

Viktoria Rubel — 2025-03-26

The object of study is the biopolymer system “X”, which is used as a clay-free drilling fluid for development of productive horizons. Biopolymer system “X” is a clay-free drilling fluid for drilling directional and horizontal wells, development of productive horizons under high pressures and temperatures.

A distinctive feature of the biopolymer system is a high level of mineralization, increased heat resistance and high density, which significantly expands the scope of clay-free muds.

At the same time, this system has a number of significant advantages:

– high level of mineralization;

– increased heat resistance (operable up to 150 °C);

– high density, which expands the scope of application;

– provides a higher coefficient of recovery of reservoir permeability compared to traditional weighted solutions;

– low content of colloidal particles, which reduces the risk of deterioration of reservoir performance;

– ability to control filtration properties at high temperatures and pressures.

The following disadvantages can be identified based on the research:

Significant increase in the filtration rate with increasing temperature (nonlinear dependence with a correlation coefficient of 0.773).
2. The need to maintain a constant concentration of potassium chloride (~3 %) to ensure the development quality of productive formations.
Difficulty in controlling the properties due to the need to accurately select the concentrations of various components (sodium chloride and organomineral colmatant).

The optimal ratio of components to ensure the stability of the system at temperatures up to 150 °C was obtained: sodium chloride concentration 15–20 %, stabilizer 0.75–1 %. This is due to the fact that the proposed composition has a number of features of synergistic interaction of the components, in particular the formation of stable complexes between biopolymers and sodium ions, which prevents the thermal destruction of polymer chains at high temperatures. At the same time, the stabilizer forms an additional protective layer around the polymer molecules, ensuring their resistance to oxidation and hydrolysis under high pressure of up to 7 MPa.

The obtained research results indicate the possibility of effective use of the biopolymer system at high temperatures and pressures due to the thermostabilizing effect of sodium chloride and organo-mineral colmatant.

Study of physicochemical and geochemical aspects of enhanced oil recovery and CO₂ storage in oil reservoirs

Taras Petrenko — 2025-03-26

The object of research is the processes of multiphase filtration in porous media. These processes occur when carbon dioxide (CO₂) is injected into oil reservoirs to increase oil recovery. The object is also the interphase phenomena, geochemical interactions and technological operations for well control associated with these processes.

One of the most problematic areas is the lack of understanding of complex relationships. These relationships exist between physicochemical processes at the micro level (interfacial tension, wettability, solubility, adsorption, geochemical reactions) and macroscopic characteristics of the reservoir (permeability, porosity, heterogeneity). Technological parameters of CO₂ injection (pressure, temperature, speed, volume) are also important. This leads to suboptimal selection of technologies for increasing oil recovery technologies, premature CO₂ breakthroughs, low oil recovery ratios, and also complicates the prediction of the behavior of the “reservoir – fluid – CO₂” system in the long term, in particular, from the point of view of CO₂ storage safety. Another problematic area is the limitation of existing empirical models describing the impact of CO₂ injection on well productivity, which do not fully take into account the heterogeneity of the reservoir and the complexity of physicochemical processes.

A comprehensive overview of the mechanisms of CO₂ interaction with reservoir fluids and rock has been obtained. The impact of supercritical CO₂ on interfacial tension, wettability, swelling and viscosity of oil has been analyzed. Geochemical reactions and their impact on permeability have been considered. CO₂ mobility control has been investigated. Mathematical relations for the calculation of throttling devices have been developed. An analysis of industrial data has been conducted, which revealed a nonlinear response of wells and allowed to refine regression models.

This provides the possibility of obtaining increased oil recovery rates and long-term CO₂ binding. Compared with similar known methods, CO₂ provides a decrease in interfacial tension, a decrease in oil viscosity, dissolution of residual oil and a potential reduction in greenhouse gas emissions. Refined regression models allow for a more accurate prediction of well productivity. The developed mathematical relationships provide effective well management. The results obtained can be used in practice to optimize oil field development processes using CO₂ injection technologies, as well as to assess and ensure the safety of long-term CO₂ storage in geological formations.

Threshold effects of globalization on economic growth: insights from Azerbaijan using regression and Fuzzy C-Means

Latafat Gardashova — 2025-03-26

The object of this research is the relationship between globalization and economic growth in Azerbaijan, analyzed using regression analysis and Fuzzy C-Means (FCM) clustering. While globalization is often linked to economic expansion, its effects in resource-dependent economies remain unclear. This study examines whether increasing globalization, measured by the KOF Globalization Index and its sub-indices (economic, social, and political globalization), positively impacts GDP per capita growth.

Regression analysis reveals significant negative impacts of globalization on GDP per capita growth, with social globalization showing the strongest negative effect (coefficient: –10.93, p<0.01), followed by political (–9.55, p<0.01) and economic globalization (–5.96, p<0.05). Conversely, institutional quality, measured by the rule of law, significantly promotes growth (10.22, p<0.01). Fuzzy C-Means clustering further identifies clear nonlinear (threshold) patterns: moderate globalization levels (KOF Globalization Index≈49.36) correspond with the highest average GDP per capita growth (≈14.47), whereas lower (≈32.13) and higher (≈62.52) levels associate with significantly lower or negative growth (–10.91 % and 1.29 %, respectively). These findings indicate that excessive global integration can undermine economic stability in resource-dependent economies at the early stages of industrialization, such as Azerbaijan.

In practice, globalization should be approached strategically. Policymakers must strengthen institutions, enhance long-term investment policies, and prioritize industrial learning before promoting deeper integration. A balanced approach will maximize globalization’s benefits while minimizing risks.

Development of a decision support methodology for optimizing ROI in project management

Alish Nazarov — 2025-04-09

The object of this research is the decision-making process in project management aimed at increasing efficiency and optimizing return on investment (ROI). One of the most problematic areas identified during the audit is the limited capability of traditional multi-criteria decision-making (MCDM) methods – such as multi-objective optimization on the basis of ratio analysis (MOORA) and weighted aggregated sum product assessment (WASPAS) – to operate effectively under uncertainty, incorporate qualitative expert judgments, ensure objectivity in calculations, and maintain ranking stability when criteria weights change or when new alternatives and external factors are introduced – conditions often present in real-world management scenarios.

To address these limitations, the study employs an integrated fuzzy decision-making model that combines the fuzzy analytic hierarchy process (Fuzzy AHP) and the fuzzy technique for order preference by similarity to ideal solution (Fuzzy TOPSIS). Fuzzy AHP is used to determine the weights of criteria through expert pairwise comparisons, incorporating linguistic assessments transformed into triangular fuzzy numbers. Fuzzy TOPSIS ranks project alternatives by measuring their closeness to the ideal solution under uncertain conditions.

The proposed methodology also includes sensitivity analysis and rank reversal testing to validate the model’s robustness. The results demonstrate a stable ranking of three project alternatives, with Alternative B achieving the highest closeness coefficient (0.6628), indicating its superior investment attractiveness.

This decision support model integrates expert knowledge, fuzzy logic, and mathematical modeling, and is adaptable to changes in data, incomplete information, and varying evaluation criteria. Compared to classical MCDM approaches, it offers improved accuracy, flexibility, and robustness for strategic decision-making in dynamic environments.

Diagnostics of the technical state of high-voltage equipment under operating voltage

Oleksandr Sakhno — 2025-03-31

The object of research is systems for online monitoring of the technical condition of oil-filled high-voltage electrical equipment during operation, which are used for automated diagnostics of the technical condition of equipment, resource forecasting and reducing of accidents.

The work is devoted to finding opportunities to reduce the cost of online monitoring systems, taking into account the military situation in Ukraine. The problem is caused by the need to use such systems to increase personnel safety and reliability of power grids, reduce the risk of failures due to deterioration of the technical condition of equipment due to unforeseen resource depletion or accelerated development of hidden defects due to military actions (excessive short-circuit currents, overvoltage). But taking into account the fact that the restoration of the power structure of Ukraine takes place in conditions of limited financial resources, one of the important tasks is to use online monitoring systems with an optimal price/diagnostic capabilities ratio to ensure the required level of diagnostics with a reduction in material costs for such systems.

The paper presents the results of an analytical study of the operation of online monitoring systems operated at various facilities over the past 20 years. The approach to diagnostics under operating voltage proposed in this study is aimed, first of all, at preventing emergency situations caused by the most frequent causes of accidents associated with: partial breakdown of capacitor insulation, increase in relative moisture saturation of transformer oil, appearance of dissolved gases in oil. The use of such an approach will increase the reliability of the power infrastructure and improve fault detection and preventive maintenance strategies while reducing the costs of organizing automated diagnostics in relation to “full-range” online monitoring systems of high-voltage equipment, which have been actively installed in Ukraine in recent years.