Energy and Power Engineering

Both Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs) need a traction motor and a power inverter to drive the traction motor. The requirements for the power inverter include high peak power, optimum consumption of energy, low output harmonics and inexpensive circuit. In this paper, a new structure of multilevel inverter with reduced number of switches is proposed for electric vehicle applications. It consists of an H-bridge and an inverter in each phase which produces multilevel voltage by switching the dc voltage sources in series. As the number of switches are reduced, both conduction and switching losses will be decreased, which leads to increase the efficiency of converter. The size and power consumption of driving circuits are also reduced. The proposed three phase inverter can produces more number of voltage levels in the same number of the voltage source and reduced number of switches compared to the conventional inverters. This structure minimizes the total harmonic distortion (THD) of the output voltage waveforms. The structure of proposed multilevel inverter, modulation method, switching losses, THD calculation and simulation results with PSCAD/EMTDC software are shown in this paper.

Both Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs) need a traction motor and a power inverter to drive the traction motor. The requirements for the power inverter include high peak power, optimum consumption of energy, low output harmonics and inexpensive circuit. In this paper, a new structure of multilevel inverter with reduced number of switches is proposed for electric vehicle applications. It consists of an H-bridge and an inverter in each phase which produces multilevel voltage by switching the dc voltage sources in series. As the number of switches are reduced, both conduction and switching losses will be decreased, which leads to increase the efficiency of converter. The size and power consumption of driving circuits are also reduced. The proposed three phase inverter can produces more number of voltage levels in the same number of the voltage source and reduced number of switches compared to the conventional inverters. This structure minimizes the total harmonic distortion (THD) of the output voltage waveforms. The structure of proposed multilevel inverter, modulation method, switching losses, THD calculation and simulation results with PSCAD/EMTDC software are shown in this paper.

AREVA operates a world-wide unique thermal hydraulic platform to ensure high safety standards in the nuclear industries. This platform is operated as an accredited test and inspection body according to ISO 17025 and 17020 to grant a high and independently confirmed quality standard. The accreditation also ensures the independency of the organization and confidentiality to the individual stakeholders, for example research centers, utilities, components suppliers, engineering companies and vendors. Especially for nuclear power plants, it is very relevant to consider that reliability depends on the integrity of its components during its life time-from design through construction, operation and maintenance. For example, a typical NPP (nuclear power plant) has 1,000 to 2,000 large valves and 7,500 to 12,500 small valves, of which about 200 to 400 are designated Safety Class 1. The qualification of these Safety Class 1 components is relevant for reactor new builds but also for installed plants. This paper explains newly established qualification tasks, the corresponding testing infrastructure, and the state of the art of testing technology. By way of example, the paper describes the program and possible sequence of qualifying NPP safety-related components.

Despite the tremendous efforts exhibited by various utilities around the world during the past few years, there are still exceedingly many remote regions unreached by the electrical grid. For those regions, the enormous available potential of renewable energy resources is believed to be useful for the development of a stand-alone power supply system. This paper presents the modeling of a stand-alone hybrid system for the remote area of Ethiopia. A comparison of the economic performance of various scenarios of a stand-alone photovoltaic (PV)-wind hybrid system, with battery storage and diesel as a backup for electrifying remote rural areas, is presented. Therefore, a practical example, Kutur village of Awlio kebele of the Axum district, Ethiopia (which is 30 km away from the closest national grid) is considered for this research. Two electric load scenarios are estimated by considering the set of incandescent and efficient lamps for lighting for the 120 existing households. The above...

The deforestation associated with the production of traditional wood-based particleboards requires the exploration of sustainable alternatives. This research investigates the potential use of Imperata cylindrica (Iluk), a fastgrowing and readily available perennial grass, as a viable raw material for particleboard specifically designed for interior applications. The study explores the feasibility of substituting the Iluk plant for wood in particleboard production. It analyses the mechanical properties (strength, durability, moisture resistance) of Iluk-based particleboard compared to conventional alternatives. In addition, a life cycle assessment is conducted to quantify the environmental benefits of using Iluk. This research aims to Assess the feasibility of using Iluk particles to develop a functional particle board suitable for interior use. Evaluation of performance characteristics of Iluk-based particle board compared to conventional particle board. Investigate the environmental benefits associated with using Iluk as a sustainable alternative. The findings of this research contribute to the development of sustainable alternatives in the construction and furniture industry. Successful results may lead to a reduced dependence on traditional wood resources and a more environmentally friendly approach to particleboard production.

The deforestation associated with the production of traditional wood-based particleboards requires the exploration of sustainable alternatives. This research investigates the potential use of Imperata cylindrica (Iluk), a fastgrowing and readily available perennial grass, as a viable raw material for particleboard specifically designed for interior applications. The study explores the feasibility of substituting the Iluk plant for wood in particleboard production. It analyses the mechanical properties (strength, durability, moisture resistance) of Iluk-based particleboard compared to conventional alternatives. In addition, a life cycle assessment is conducted to quantify the environmental benefits of using Iluk. This research aims to Assess the feasibility of using Iluk particles to develop a functional particle board suitable for interior use. Evaluation of performance characteristics of Iluk-based particle board compared to conventional particle board. Investigate the environmental benefits associated with using Iluk as a sustainable alternative. The findings of this research contribute to the development of sustainable alternatives in the construction and furniture industry. Successful results may lead to a reduced dependence on traditional wood resources and a more environmentally friendly approach to particleboard production.

This study explores the implementation of path-planning algorithms in resource-constrained autonomous vehicles within a university environment, specifically NSBM Green University. Unlike most studies that assume abundant resources, this research focuses on cost-effective solutions suitable for environments with limited financial and computational capabilities. The methodology involved an extensive review and analysis of existing pathplanning algorithms and localization methods, followed by simulations using MATLAB. The selected algorithm, Hybrid A*, was optimized to balance computational efficiency, path accuracy, path length, and obstacle avoidance. The results confirmed that reliable autonomous navigation is achievable even under resource constraints. Future work will involve creating a more detailed map of the university and testing more complex algorithms to further enhance the robustness of the path planning system. Additionally, the optimized algorithm could be tested in real-world scenarios to validate its practical feasibility for autonomous navigation.

Head trauma is a major health concern worldwide, resulting in death or permanent disability. 1.7 to 3.8 million traumatic brain injuries are reported in the United States every year [1]. 10% of these injuries occur during sports and recreational activities. This poses a significant risk factor to solo travelers and extreme sports enthusiasts, who are more likely to be in remote locations with reduced access to healthcare. Timely medical intervention can prevent the escalation of secondary complications, which could potentially lead to more severe neurological deficits and life-threatening conditions. This research presents an innovative choice of headgear, which precisely pinpoints the area of impact facilitating the efficient administration of first aid, prior to thorough examination through advanced medical equipment. This ensures reactive safety whilst minimizing interference with proactive safety headgear.

The rapid increase in electricity demand has led to innovative peak demand control processes, notably Vehicle-to-Grid (V2G) technology. V2G enables electric vehicles (EVs) to both draw power from and release stored energy back to the grid, making EVs mobile energy storage units. Traditional peak load management strategies are insufficient for modern energy demands, requiring comprehensive methodologies for effective dynamic peak load management using EVs in island mode microgrids. Integrating renewable energy sources enhances grid stability and sustainability. V2G technology's bidirectional power exchange allows EVs to balance demand and supply while supporting grid stability. This research focuses on maximizing efficiency, managing peak load demand, and improving grid stability with V2G technology, transforming EVs into energy management assets. By using EV batteries to meet peak demand, reduce fossil fuel-based power plant expenses, and lower generation costs, the study aims to optimize energy utilization and island-mode microgrid stability in a simulated city under various conditions.

With the innovation of V2G technology, it facilitates energy change in both directions between electric vehicles and conventional power grids. It aims to improve the efficiency, reliability, and sustainability of energy systems. There are benefits as well as challenges for smooth implementation and operation. So, this research focuses on addressing the challenges and assessing the technical feasibility of integrating V2G technology in island-mode microgrids using MATLAB simulations. Then, analyze the impact of V2G technology on the operational dynamics and stability of the island-mode microgrid. Islandmode microgrids are independent of the main power grid, and their electricity demand is fulfilled by the localized energy sources of the microgrid. The simulated city is powered by renewable sources, and EVs are used in critical situations. EVs store energy in batteries and supply it to the grid, as it enables bidirectional energy flow between EVs and the grid. Though traditional microgrids face challenges in balancing demand and supply, ensuring continued power supply while maintaining stable frequency and voltage levels, V2G technology offers a better solution for those challenges. The significance of the study is the technical feasibility of V2G technology in the simulated city. It consists of an island-mode microgrid of renewable energy sources with a battery management system to power up the city. By analyzing the impact of V2MG technology on island-mode microgrids, this research aims to depict the improvement in grid stability and reliability of microgrids compared to traditional microgrids. This study focuses on different conditions and scenarios of EV charging and discharging to supply power to the city and analyzes the impact of V2G technology.

Enhancing the resilience of microgrids involves implementing strategies and technologies that improve their robustness and reliability. Islanded microgrids, operating independently from the main utility grid, face significant challenges in maintaining a stable power supply, especially with the integration of intermittent renewable energy sources. This research proposes the implementation of a Fuzzy Logic Controller driven Battery Energy Storage System to enhance the resilience of such microgrids. By employing an advanced FLC, the study aims to dynamically adjust the operational modes of the microgrid based on real-time assessments of energy availability and demand. The methodology incorporates a Mixed Integer Linear Programming model to optimize the sizing and management of the BESS, facilitating improved energy distribution and reduced reliance on diesel generators. This approach is expected to enable more sustainable management of energy resources, significantly lower operational costs, and improve the environmental footprint of islanded microgrid systems. The integration of FLC with BESS represents a forward-thinking solution to the operational challenges faced by less infrastructure or independent energy systems, aiming to establish a more reliable, efficient, and adaptable energy management framework.

The reliability and efficiency of solar PV power generation are heavily influenced by various weather conditions, which induce randomness, volatility, and intermittency in power output. Accurately forecasting solar power output is crucial for minimizing the impact of these fluctuations on the stability and operational efficiency of the power grid system. This not only aids in balanced grid operation and optimized dispatch but also significantly reduces operating costs. Given the growing interest in reducing the uncertainties associated with short-term solar PV power predictions, this study develops and evaluates an AI-based forecasting model tailored to these needs. Utilizing a comprehensive dataset collected from a rooftop solar installation in Kadawatha, Sri Lanka, which includes parameters like temperature, relative humidity, and global solar radiation, this research applies advanced machine learning techniques specifically artificial neural networks (ANN), Support Vector Machine (SVM) and gradient boosting. The models are trained to recognize and predict power output fluctuations under diverse weather scenarios, aiming to enhance forecasting accuracy. Initial results confirm the potential of AI models to significantly improve the predictability of solar power generation, thereby supporting more sustainable and efficient energy management practices.

This paper explores the application of Superconducting Magnetic Energy Storage (SMES) based Dynamic Voltage Restorer (DVR) systems to improve voltage sag and swell issues in Sri Lanka's low voltage three-phase power system. Voltage sags and swells are critical power quality problems that can cause significant disruptions in both residential and industrial sectors. Voltage sags, often caused by short circuits, motor startups, or sudden increases in load, and voltage swells, typically resulting from abrupt load drops or capacitor bank switching, are common in industrial settings. The integration of SMES with DVR technology offers a promising solution by providing rapid and precise voltage correction. This study analyses the operation principle of the SMES-based DVR and designs the DVR output voltage control method using MATLAB SIMULINK [1]. Voltage sags and swells are detected using a power quality analyzer connected to the low-voltage three-phase power system. The collected data are used to simulate voltage sags and swells in MATLAB. The models of the SMES-based DVR are established, and simulation tests are performed to evaluate system performance. The results demonstrate significant improvements in voltage regulation, highlighting the feasibility and effectiveness of SMES-based DVR systems in enhancing power quality and reliability in Sri Lanka's low-voltage distribution network [2].

This research proposes to modify the Particle Swarm Optimization (PSO) technique to make it compliant with the greatest power point of solar photovoltaic panels and increase its efficiency. The architecture including a boost converter will help increase the voltage of the batteries and raise overall efficiency. The proposed approach finds out the relation of connected loads with solar PV generation in a way to sustain maximized Photovoltaic (PV) efficiency. It extracts the most available power using Maximum Power Point Tracking (MPPT) and utilizes solar energy in periods of its availability at top priority. In this research study, a modified PSO will be used for MPPT in solar panels. The algorithm will be tested through experimental analysis and simulation. Performance metrics of prime interest are the efficiency of charging, the quantity of renewable energy consumed, and the availability of the system. It is shown that with the proposed modified PSO-based MPPT, an efficiency near 95% can be reached.

Adsorption chiller technology has received much attention in the last few decades due to its advantages in utilizing low grade thermal energy and eco-friendly refrigerant. However, it has not been wide commercialized due to its low coefficient of performance (COP) and low specific cooling power (SCP) compared to conventional refrigeration technologies. This paper reviews different strategies to improve the COP and SCP of adsorption chillers. Heat recovery, mass recovery, multi-stage, multi-bed, improved adsorption structures and optimized operating conditions are discussed in this review. This study revealed that: (i) for operating conditions of low evaporative temperature, low generation temperature or high condensing temperature, a mass recovery technique is strongly recommended; (ii) in the case of intermittent cold production systems, use of constant temperature adsorption cooling cycle strategy is preferred; (iii) an appropriate cycle time and switching time are important to achieve the optimal system performance since the adsorption chiller performance is strongly dependent on the operating conditions; (iv) by employing a novel composite adsorbent material, along with improvements in heat exchanger design, advanced adsorption cycles can be a promising technology to improve adsorption chiller performance. This review highlights the need for further research to reduce chiller manufacture costs, increase power-to-mass ratio and improve understanding of dynamic long term chiller performance when driven by solar or waste thermal energy.

The present study focuses on the design and choice of materials (steels S355 and 45SCD6) of a chassis of stirred tank (with a variable filling rate) for use in the manufacturing of cosmetic products. This tank or trough will be submitted to important mechanical and thermal loads and pressure according to the various manufacturing processes. The authors propose a model of thermal and mechanical loads which takes into account the operating conditions of the tank. The analysis of the first 10 modes of vibration of the frame shows that the frequencies are much higher when the filling rate is high. They are higher for steel 45SCD6 than for the S355. The simulation results show that for a selected type of steel, the equivalent Von Mises stress increases along with increase in fill rates and thermal gradient. It appears that the influence of the thermal gradient is predominant. For both steels, the Von Mises equivalent stress is maximum in the beam 32 when the thermal gradient is at its lowest stage, and in the beam 40 for the greatest thermal gradient.

Pakistan is facing acute energy crises since last few years. Due to shortage of fuel oil and its sky touching prices, it seems very uneconomical to generate electricity from fuel oil. In order to generate cheap electricity we have to rely on renewable energy resources. To address these challenges, wind power generation is among the popular options in the world which is now being considered in Pakistan as well. However unremitting change in wind speed from calm to stormy introduces real challenges. Storing wind energy in batteries during the periods of low demand seems an expensive option, especially when dealing with large scale power generation. Due to incessantly varying nature of wind speed, it is not feasible to rely only on wind power for cheap power production. Also, it is not thriftily possible to construct separate transmission line. However if we integrate wind power with hydro power, we can utilize the maximum possible transmission capacity. Existing hydro power station operating in that area or pumped storage scheme can be used. This paper is an attempt to analyze coordination of wind generation with hydro power in those areas of Pakistan where both wind and hydro power sources exist. In this paper, different issues have been analyzed taking case study of Dargai. This paper is first attempt in Pakistan about integration of wind and hydro power to draw some general conclusions and to point out some areas in which further research can be done.

Since renewable energy sources (RES) have almost little inertia, an increase in their electricity might harm the power system's ability to run steadily and dependably. Numerous solutions to the issue mentioned above are offered. This paper aims to assess the technological possibility of using energy storage system (ESS) devices built from batteries and supercapacitors to enhance the interia response of sources in microgrids with a large amount of PV power penetration. The microgrid's inertia was altered by varying the penetration level of RES. To obtain a rigid microgrid, batteries and supercapacitors are suggested in this study to enhance frequency stability and droop control is utilized to complete this assessment. The model of the on-grid power network was designed using Simulink in MATLAB to evaluate the high level of RES penetration impact on the frequency stability of the system. Results verify that the microgrid stiffness is significantly enhanced when the suggested storage elements are incorporated. The findings show that the rate of change of frequency (RoCoF) is reduced when the size of the ESS increases and vice versa. The supercapacitor energy storage system (SCESS) can increase the stability of the system's frequency more effectively than the battery energy storage systems (BESS) with a slower time response.

AREVA operates a worldwide unique thermal hydraulic platform to ensure high safety standards in the nuclear industries. This platform is operated as an accredited test and inspection body according to ISO 17025 and 17020 to grant a high and independently confirmed quality standard. The accreditation also ensures the independency of the organization and confidentiality to the individual stakeholders, for example research centers, utilities, components suppliers, engineering companies and vendors. Especially for nuclear power plants, it is very relevant to consider that reliability depends on the integrity of its components during its life time-from design through construction, operation and maintenance. For example, a typical NPP (nuclear power plant) has 1,000 to 2,000 large valves and 7,500 to 12,500 small valves, of which about 200 to 400 are designated Safety Class 1. The qualification of these Safety Class 1 components is relevant for reactor new builds but also for installed plants. This paper explains newly established qualification tasks, the corresponding testing infrastructure, and the state of the art of testing technology. By way of example, the paper describes the program and possible sequence of qualifying NPP safety-related components.

Ferrites such as (A x B y)Fe z O 4 (doped spinel) or (A x B y)Fe 1-x-y O (doped wustite) or their mixtures, where A and B are bivalent metal cations, were reported to be the most active materials for hydrogen generation using thermochemical watersplitting reactions. Although these ferrites have been synthesized by solid-state mixing, oxidation of aqueous metal hydroxide suspension, self-propagation high temperature synthesis and aerosol spray pyrolysis methods, the use of sol-gel derived ferrites for thermochemical water-splitting reactions is very limited. The sol-gel synthesis method provides better control over stoichiometry and powder characteristics. The powders produced by the sol-gel synthesis method usually have higher specific surface area, which may provide a higher number of active sites for water-splitting reactions. In this investigation, Sn-ferrite and Sn doped Ni-ferrite were synthesized using a sol-gel technique wherein Ni, Sn and Fe salts were dissolved in ethanol by sonication with the gel formation being accomplished by adding propylene oxide. The gels were aged for 48 h, dried at 100 o C for 1 h, and finally calcined at 900 o C in an air environment. The calcined powder was characterized using powder X-ray diffraction, Brauner-Emmett-Teller surface area analysis and scanning electron microscopy. After the powder was placed in a packed bed reactor, the water-splitting reaction was carried out at 700 o C. After each water-splitting reaction, oxidized ferrite was regenerated at 900 o C for 2 h in an N 2 environment. Synthesis method, characterization, and transient hydrogen profiles obtained at various experimental conditions will be presented in detail.

We present the preparation and characterization of doped ferrites synthesized using two methods. In a combustion synthesis method, precursors such as metal (Zn, Fe, Ni) nitrates were dissolved in de-ionized water and combined with fuel, for instance, sugar, urea, or ethylenediaminetetraacetic acid (EDTA). The homogenous solution thus obtained was heat treated in a convective furnace to minimize the water content and subsequently heated to 650 °C in air at 20 °C/min for combustion to occur. Powder X-ray diffraction (XRD) analysis revealed that the ferrite synthesized with sugar was crystalline and phase pure, however, the use of urea and EDTA resulted in ferrites with multiple crystalline phases. The specific surface area of the Zn-doped ferrite prepared by the combustion approach was 17.4-19.5 m 2 /g and was found to be dependent on the fuel to precursor ratio used during synthesis. Scanning electron microscopic (SEM) images of doped ferrites exhibited the presence of agglomerated nanocrystals. In another method, ferrite foam-like material was synthesized using a sol-gel method involving the addition of polymer microspheres containing hydrocarbon gases followed by microwave heating. Specifically, the Ni and Fe precursors were added in ethanol containing surfactant/polymer microspheres, and the solution was sonicated. After the addition of propylene oxide, the gel formation was observed after 5 min. The gel was rapidly heated in a microwave furnace to 1000 oC and quenched. The SEM image indicated foam like morphology with high aspect ratio nanosize tubular structure, which was consistent throughout the sample matrix.

AREVA operates a worldwide unique thermal hydraulic platform to ensure high safety standards in the nuclear industries. This platform is operated as an accredited test and inspection body according to ISO 17025 and 17020 to grant a high and independently confirmed quality standard. The accreditation also ensures the independency of the organization and confidentiality to the individual stakeholders, for example research centers, utilities, components suppliers, engineering companies and vendors. Especially for nuclear power plants, it is very relevant to consider that reliability depends on the integrity of its components during its life time-from design through construction, operation and maintenance. For example, a typical NPP (nuclear power plant) has 1,000 to 2,000 large valves and 7,500 to 12,500 small valves, of which about 200 to 400 are designated Safety Class 1. The qualification of these Safety Class 1 components is relevant for reactor new builds but also for installed plants. This paper explains newly established qualification tasks, the corresponding testing infrastructure, and the state of the art of testing technology. By way of example, the paper describes the program and possible sequence of qualifying NPP safety-related components.

Nigeria's power grid is a key area that requires urgent attention to revive the nation's economy which has continued to dwindle over the years. This paper seeks to analyze the grid's performance and proposes various ways to mitigate the fragile situation of the grid.This paper makes use of the historical data of the national grid operations under review, from 2015 to 2023. The data was analyzed using descriptive statistics (tables, frequency counts, charts, and graphical depictions) to extract the prominent elements required for the study's conclusion. In the period under study (2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023), the grid experienced a total number of 101 voltage collapses which is an average of about 11 times collapses in each year. Nigeria's grid installed capacity stands at about 14,000MW and has a generating peak value of about 5,200MW and an off-peak value of about 4,400MW. Furthermore, the results show that the grid generates an average of 4,800MW which translates to about 34.64% of the installed capacity. Also, from the results it can be seen that in 2016 the nation experienced the highest number of voltage collapses of 28 times, and in 2023 it had the lowest with 2 occurrences. Various reasons ranging from poor maintenance, vandalization, OEMs issues, spares, gas constraints, radial and nonredundancy nature of the grid, etc contributed to the major causes of the grid collapses. Training, revamping the power sector, decentralization of the national grid, and embracing renewable energy sources were proffered as solutions to the current problems facing Nigeria's grid network.

Московский, государственный инженерно-физический институт Институт нефтехимического синтеза им. А.В. Топчиева РАН, г. Москва Поступила в редакцию 10.07.96 г. Представлены результаты численных исследований процесса получения азота из воздуха мембран ным методом с применением отечественных газоразделительных мембран.

Efficient provision of electricity requires timely expansions of power transmission capacity. However, regulation does not always send the right signals to generate the required (and timely) investments. Therefore, it is important to evaluate the effect of alternative regulations on investment on transmission capacity. In this paper, considering regulated remuneration, we perform this evaluation with a behavioral simulation model of the transmission capacity expansion, in which capacity is endogenously determined by the demand/supply relation. Two planning approaches were considered: centralized planning where the investments are fully coordinated by a central organism, and decentralized planning where the capacity expansions are driven by the investors' rationality on the power market evolution. The model is applied to the Colombian case. The decentralized approach has lower costs (usage charges) than centralized expansion, but lower transmission capacity margins. As low transmission capacity margins create supply risks in high demand periods, regulators can increase coordination in decentralized planning by directly promoting investments that increase security of supply.

Резюме. Цель. Целью данной работы является модернизация плотномера ВТ-КХТИ, работающего по методу гидростатического взвешивания, для исследования плотности высоковязких нефтей и нефтепродуктов в интервале изменения температур от 293 К до 473 К при атмосферном давлении. Метод. Из многочисленных методов исследования плотности в ходе исследования применены: пьезометры постоянного и переменного объемов, метод гидростатического взвешивания. Результат. Представлены результаты исследования плотности высоковязких нефтей Республики Татарстан в интервале изменения температур от 293 К до 473 К при атмосферном давлении следующих марок: Ашальчинская нефть (сверхвязкая, СВН); Куакбашская нефть (сернистая), Кичуйская нефть и Девонская нефть. Произведен анализ и выбор методик измерения плотности. Приведена методика оценки погрешности и калибровки плотномера. Рассмотрена модернизированная конструкция гидростатического плотномера для измерения плотности высоковязких нефтей. Выполнен вывод расчетного выражения для метода гидростатического взвешивания. Вывод. Плотномер ВТ-КХТИ для вакуумных рабочих жидкостей модернизирован и откалиброван для научно-исследовательских работ по измерению коэффициента динамической вязкости реовискозиметром ВТ-КХТИ, как ньютоновских, так и неньютоновских жидкостей. Исследование выполнено за счет гранта Российского научного фонда (проект №18-19-00478).

In recent years, photovoltaic (PV) modules are widely used in many applications around the world. However, this renewable energy is plagued by dust, airborne particles, humidity, and high ambient temperatures. This paper studies the effect of dust soiling on silicon-based photovoltaic panel performance in a mini-solar power plant located in Dakar (Senegal, 14˚42'N latitude, 17˚28'W longitude). Results of the current-voltage (I-V) characteristics of photovoltaic panels tested under real conditions. We modeled a silicon-based PV cell in a dusty environment as a stack of thin layers of dust, glass and silicon. The silicon layer is modeled as a P-N junction. The study performed under standard laboratory conditions with input data of irradiation at 1000 W/m 2 , cell temperature at 25˚C and solar spectrum with Air Mass (AM) at 1.5 for the monocrystalline silicon PV cell (m-Si). The analysis with an ellipsometer of dust samples collected on photovoltaic panels allowed to obtain the refraction indices (real and imaginary) of these particles which will complete the input parameters of the model. Results show that for a photon flux arriving on dust layer of 70 μm (corresponding to dust deposit of 3.3 g/m 2) deposited on silicon-based PV cells, short circuit current decreases from 54 mA (for a clean cell) to 26 mA. Also, conversion efficiency decreases by 50% compared to clean cell and the cell fill factor decreases by 76%-50% compared to reference PV cell.

Experimental measurements were conducted to determine the effect of mixing chamber length on liquid-gas ejector performance. The tests were performed on a laboratory bench designed for physically modeling the process of creating a water-gas mixture using exhaust gases. For the first time in this study, liquid-gas ejector parameters were measured during the injection of exhaust gases from a real source. The study investigated how the ratios of displacement chamber diameters, chamber length, and working nozzle affect the liquid-gas ejector's characteristics under various operating modes. The results obtained enable optimal parameter selection of the ejector and reveal the potential for utilizing exhaust gases to produce a water-gas mixture for injection into reservoirs to enhance oil recovery. Keywords: pump-ejector system; exhaust gases; liquid-gas ejector; water-gas impact; pressure-energy characteristics of the ejector.

В работе для оценки проникновения водорода через металлы нефтегазовой и химической промышленности предложена конструкция усовершенствованного электрохимического датчика, который обеспечивает увеличение точности измерений и уменьшение затрат дорогостоящих металлов и агрессивных веществ. Анализ приведенных данных волюмометрии, электрохимического диффузионного метода водопроницаемости и разработанного датчика свидетельствует о высокой достоверности определения количества дифузионно-подвижного водорода.In this paper construction of improved electrochemical sensor for the assess of penetration of hydrogen through the metals of oil-gas and chemical industries was proposed, wich provides with increasing of measurement accuracy and reducing costs of expensive metals and corrosive substances

AREVA operates a worldwide unique thermal hydraulic platform to ensure high safety standards in the nuclear industries. This platform is operated as an accredited test and inspection body according to ISO 17025 and 17020 to grant a high and independently confirmed quality standard. The accreditation also ensures the independency of the organization and confidentiality to the individual stakeholders, for example research centers, utilities, components suppliers, engineering companies and vendors. Especially for nuclear power plants, it is very relevant to consider that reliability depends on the integrity of its components during its life time-from design through construction, operation and maintenance. For example, a typical NPP (nuclear power plant) has 1,000 to 2,000 large valves and 7,500 to 12,500 small valves, of which about 200 to 400 are designated Safety Class 1. The qualification of these Safety Class 1 components is relevant for reactor new builds but also for installed plants. This paper explains newly established qualification tasks, the corresponding testing infrastructure, and the state of the art of testing technology. By way of example, the paper describes the program and possible sequence of qualifying NPP safety-related components.

The lack of water in arid and semi-arid regions has often limited agricultural production. Indeed, even where water is available for irrigation, the lack of electricity, as well as the high costs of diesel, has created constraints on small farmers. The purpose of this research is to review the renewable energy potential available in arid and semi-arid zones that can be used for irrigation as a substitute for fossil fuels. In this review, the solar thermal irrigation, solar photovoltaic (PV) irrigation, wind pumping and biomass pumping are discussed. The comparison of different hybrid pumping systems and analyses of renewable sources irrigation assessment in arid and semi-arid regions of Mozambique also are discussed. The results of this study showed that there are still certain technological limitations regarding the use of solar thermal energy for irrigation. As far as wind power is concerned, the analysis of the pumping water life cycle cost showed that the wind power water pumping system is more economical and viable compared to the diesel based system. However, the study concluded that photovoltaic solar energy has been shown to be more viable for pumping water for irrigation in arid and semi-arid regions.

В роботі розглянуто задачу синтезу намагнічуючих пристроїв магнітного неруйнівного контролю. Розроблено програмні засоби проектування магнітних систем, що дозволяють створювати у робочому просторі пристрою контролю магнітні поля з високим ступенем однорідності та високою інтенсивністю.In this work a synthesis problem of magnetizing devices for nondestructive control is considered. The designed software tools let to create a high intensive and uniform magnetic field inside an effective volume of the control device

Pakistan is facing acute energy crises since last few years. Due to shortage of fuel oil and its sky touching prices, it seems very uneconomical to generate electricity from fuel oil. In order to generate cheap electricity we have to rely on renewable energy resources. To address these challenges, wind power generation is among the popular options in the world which is now being considered in Pakistan as well. However unremitting change in wind speed from calm to stormy introduces real challenges. Storing wind energy in batteries during the periods of low demand seems an expensive option, especially when dealing with large scale power generation. Due to incessantly varying nature of wind speed, it is not feasible to rely only on wind power for cheap power production. Also, it is not thriftily possible to construct separate transmission line. However if we integrate wind power with hydro power, we can utilize the maximum possible transmission capacity. Existing hydro power station operating in that area or pumped storage scheme can be used. This paper is an attempt to analyze coordination of wind generation with hydro power in those areas of Pakistan where both wind and hydro power sources exist. In this paper, different issues have been analyzed taking case study of Dargai. This paper is first attempt in Pakistan about integration of wind and hydro power to draw some general conclusions and to point out some areas in which further research can be done.

Using a working catalyst (0.75In203-0.25Ag20) and a reference (0.25Рез0.г0.75№20з) element, a sensor was manufactured to determine methane (natural gas) in the presence of carbon monoxide and hydrogen. Optimal values of voltage supply were selected, warm-up time, dynamic, and calibration characteristics of the sensor were studied.

Pakistan is facing acute energy crises since last few years. Due to shortage of fuel oil and its sky touching prices, it seems very uneconomical to generate electricity from fuel oil. In order to generate cheap electricity we have to rely on renewable energy resources. To address these challenges, wind power generation is among the popular options in the world which is now being considered in Pakistan as well. However unremitting change in wind speed from calm to stormy introduces real challenges. Storing wind energy in batteries during the periods of low demand seems an expensive option, especially when dealing with large scale power generation. Due to incessantly varying nature of wind speed, it is not feasible to rely only on wind power for cheap power production. Also, it is not thriftily possible to construct separate transmission line. However if we integrate wind power with hydro power, we can utilize the maximum possible transmission capacity. Existing hydro power station operating in that area or pumped storage scheme can be used. This paper is an attempt to analyze coordination of wind generation with hydro power in those areas of Pakistan where both wind and hydro power sources exist. In this paper, different issues have been analyzed taking case study of Dargai. This paper is first attempt in Pakistan about integration of wind and hydro power to draw some general conclusions and to point out some areas in which further research can be done.

Nigeria's power grid is a key area that requires urgent attention to revive the nation's economy which has continued to dwindle over the years. This paper seeks to analyze the grid's performance and proposes various ways to mitigate the fragile situation of the grid.This paper makes use of the historical data of the national grid operations under review, from 2015 to 2023. The data was analyzed using descriptive statistics (tables, frequency counts, charts, and graphical depictions) to extract the prominent elements required for the study's conclusion. In the period under study (2015-2023), the grid experienced a total number of 101 voltage collapses which is an average of about 11 times collapses in each year. Nigeria's grid installed capacity stands at about 14,000MW and has a generating peak value of about 5,200MW and an off-peak value of about 4,400MW. Furthermore, the results show that the grid generates an average of 4,800MW which translates to about 34.64% of the installed capacity. Also, from the results it can be seen that in 2016 the nation experienced the highest number of voltage collapses of 28 times, and in 2023 it had the lowest with 2 occurrences. Various reasons ranging from poor maintenance, vandalization, OEMs issues, spares, gas constraints, radial and nonredundancy nature of the grid, etc contributed to the major causes of the grid collapses. Training, revamping the power sector, decentralization of the national grid, and embracing renewable energy sources were proffered as solutions to the current problems facing Nigeria's grid network.

Разработаны экспериментальная установка для количественного определения параметров массопроводности в свином мясе под воздействием тока электроосмоса и соответствующая методика проведения экспериментальных исследований. Исследованы процессы массопроводности в образцах, изготовленных из длиннейшей мышцы свинины, под воздействием тока электроосмоса. Установлено влияние разности потенциалов тока электроосмоса, времени воздействия и физических параметров свиного мяса на количественные параметры массопроводности. Предложены аналитические зависимости для определения количественных параметров массопроводности в свином мясе под воздействием тока электроосмоса. Предложен способ количественного определения коэффициента массопроводности в мясе под воздействием тока электроосмоса

В работе представлена методика модификации короткозамкнутой линии для исследования температурной зависимости комплексной диэлектрической проницаемости ε* в диапазоне микроволн. Ключевые слова: диэлектрическая спектроскопия, диэлектрическая релаксация, диэлектрические свойства хлорбензола.

Аннотация. В статье проанализировано влияние некоторых конструктивных параметров теплового расходомера на его радиальный и осевой тепловые потоки в трубке (диаметр трубки, диаметр нагревателя и их соотношение, теплопроводность материала трубки). Приведены соотношения диаметра трубки к диаметру нагревателя расходомера для различных по теплопроводности материалов трубки при минимальном их влиянии на погрешность измерения расхода топлива. Ключевые слова. Тепловой поток, тепловой расходомер, расход топлива, конструктивный коэффициент, теплопроводность, коэффициент теплопроводности

Аннотация. В статье проанализировано влияние некоторых конструктивных параметров теплового расходомера на его радиальный и осевой тепловые потоки в трубке (диаметр трубки, диаметр нагревателя и их соотношение, теплопроводность материала трубки). Приведены соотношения диаметра трубки к диаметру нагревателя расходомера для различных по теплопроводности материалов трубки при минимальном их влиянии на погрешность измерения расхода топлива. Ключевые слова. Тепловой поток, тепловой расходомер, расход топлива, конструктивный коэффициент, теплопроводность, коэффициент теплопроводности

In this study, water was used as energy carrier for H2 generation via thermochemical water-splitting process using core-shell nanoscale ferrite material, which was synthesized using pluronic P123 templating assisted sol-gel method. Ferrite nanoparticles with porous zirconia shell were thoroughly characterized by powdered x-ray diffraction and BET surface area analyzer. This material was utilized in a continuous flow through tubular reactor as a packed-bed for thermochemical water-splitting process where the regeneration and water-splitting steps were carried out at 1100 o C and 900 o C, respectively under continuous N2 flow of 35 cm 3 .min-1 at STP conditions. At these process conditions, five thermochemical cycles were performed. The transient profiles were analyzed to determine the hydrogen volume generation as well as rate of hydrogen generation. Thermochemical water-splitting reactor was integrated with a hydrogen fuel cell to determine the energy conversion. Pressure drop (p) for the packed-bed of Niferrite(c)/ZrO2(s) core-shell nanoparticles was calculated and compared with the packed-bed of Ni-ferrite nanoparticles. In addition, the current output for the hydrogen fuel cell was monitored as a function of hydrogen flow rate.

During thermochemical water-splitting process for hydrogen generation, ferrite nanoparticles undergo significant grain growth that reduces their surface area and affect the porous morphology. Consequently, hydrogen volume generation diminishes with increase in thermochemical cycles. In order to mitigate the grain growth, we have encapsulated the ferrite nanoparticles with porous shell of thermally stable ceramic material. Ni-ferrite nanoparticles were synthesized using the sol-gel method and further utilized to prepare core-shell nanoparticles with ZrO 2 or Y 2 O 3. As-prepared core-shell NiFe 2 O 4 /ZrO 2 nanoparticles were analyzed by powdered X-Ray diffraction, transmission electron microscopy (TEM) and BET specific surface area analyzer. TEM analysis indicated core-shell morphology with Ni-ferrite encapsulated inside ZrO 2 shell of average thickness of 6.12 nm. Core-shell Ni-ferrite/ZrO 2 nanoparticles were loaded in Inconel reactor and five consecutive thermochemical cycles were performed at 900 o-1100 o C for hydrogen generation. The results indicated relatively steady hydrogen volume generation in multiple thermochemical cycles.

During thermochemical water-splitting process for hydrogen generation, ferrite nanoparticles undergo significant grain growth that reduces their surface area and affect the porous morphology. Consequently, hydrogen volume generation diminishes with increase in thermochemical cycles. In order to mitigate the grain growth, we have encapsulated the ferrite nanoparticles with porous shell of thermally stable ceramic material. Ni-ferrite nanoparticles were synthesized using the sol-gel method and further utilized to prepare core-shell nanoparticles with ZrO 2 or Y 2 O 3. As-prepared core-shell NiFe 2 O 4 /ZrO 2 nanoparticles were analyzed by powdered X-Ray diffraction, transmission electron microscopy (TEM) and BET specific surface area analyzer. TEM analysis indicated core-shell morphology with Ni-ferrite encapsulated inside ZrO 2 shell of average thickness of 6.12 nm. Core-shell Ni-ferrite/ZrO 2 nanoparticles were loaded in Inconel reactor and five consecutive thermochemical cycles were performed at 900 o-1100 o C for hydrogen generation. The results indicated relatively steady hydrogen volume generation in multiple thermochemical cycles.