Stable Demand Research Articles

Power electronics for green hydrogen generation with focus on methods, topologies, and comparative analysis.

This research article meticulously examines advanced power electronic converters crucial for optimizing electrolyzer perfor- mance in hydrogen production systems. It conducts a thorough review of mature electrolyzer types, detailing their specifications, electric models, manufacturers, and scalability. To meet the high current and stable DC voltage demands of industrial electrolyzers, the study delves into a broad spectrum of AC-DC and DC-DC converter topologies. It explores cutting-edge solutions like 12-pulse and 20-pulse rectifiers, advanced higher multi-pulse rectifiers utilizing conventional and auto-connected transformer units, Multi-Step Auto-connected Transformers (MSAT), polygon autotransformers, and auxiliary filters and circuits such as pulse multiplication circuits and active power filters. These innovations significantly reduce harmonic distortions and enhance power quality, addressing challenges inherent in conventional 6-pulse diode bridge rectifiers. The research also focuses on the efficiency and power factor correction capabilities of Active Front End (AFE) converters and the 3L-DNPC rectifier. Additionally, it investigates various DC-DC converters, including the Continuous Input Current Non-Isolated Bidirec- tional Interleaved Buck-Boost DC-DC Converter, the Interleaved Buck Converter (IBC) with extended duty cycles, the 3-level buck-boost converter with a coupled inductor, Quadratic converters designed for fault tolerance, the three-level interleaved buck converter, among others. Converter designs like the galvanically isolated half-bridge converter with controlled reverse-blocking switches for achieving zero voltage switching (ZVS), the Push-Pull isolated DC-DC converter prioritizing current stability, and the Isolated Full-Bridge Boost Converter (IFBBC) adept at handling fluctuating power outputs from renewable sources are also explored. Moreover, the study scrutinizes a range of converter configurations such as the Two-stage ZVT boost converter with LCL-Type SRC, multiphase interleaved DC-DC stage, and three-port isolated DC/DC converter for efficient integration with multiple energy sources concurrently. Discussing feature trends in power-to-hydrogen systems, the research reviews multi-cell modular rectifiers and multi-stage rectifiers. Overall, the study underscores the critical role of advanced converter topologies in enhancing efficiency, reliability, and power quality in electrolyzer systems, thereby contributing significantly to the progression of sustainable energy technologies.

СВІТОВІ ТРЕНДИ У АВТОМОБІЛЕБУДІВНІЙ ГАЛУЗІ: УРОКИ ДЛЯ РОЗВИТКУ АВТОМОБІЛЕБУДУВАННЯ УКРАЇНИ В УМОВАХ ЕКОНОМІЧНОЇ ГЛОБАЛІЗАЦІЇ

The article demonstrates that the automotive industry is a significant component of the global economy due to its overall market volume, contribution to GDP, and the number of employed workers. The importance of the automotive industry has prompted an exploration of current global trends in the automotive industry. The trends identified include the development of 'green' technologies in the context of addressing climate change, the rise of 'green' protectionism, and the intensification of economic rivalry between China and Western countries. Other trends encompass the proliferation of autonomous vehicles based on the advancement of artificial intelligence technologies, the integration of cars into the broader network of connected devices within the Internet of Things and cloud technologies, the increased concentration of global value chains, the growth of the sharing economy, urbanization, and the development of urban transport. Furthermore, there is a heightened emphasis on the safety of vehicles, along with regulatory frameworks addressing these requirements. The emergence and development of individual flying devices as alternative modes of transportation are also noteworthy trends. With the aim of assessing the relevance of these trends for Ukraine and their implementation, manifestations of these trends in Ukraine have been evaluated. It has been shown that the most pronounced manifestations include the increased concentration of global value chains and urbanization along with the development of urban transport. To assess the prospects for further development of the examined trends in Ukraine, an evaluation of the readiness of the Ukrainian economy to implement these trends in the automotive industry is presented. The analysis reveals that the Ukrainian economy is most prepared for trends such as the development of 'green' technologies in the context of combating climate change and the growth of the sharing economy. It is shown that the trends in automotive engineering both present opportunities and pose threats to domestic car manufacturers. The composition of these opportunities and threats is outlined. Explored opportunities are mainly associated with the emergence of additional market segments, a stable demand pattern, and the creation of additional economic advantages. The presented threats are mostly linked to changes in demand structure and the insufficient competitiveness of Ukrainian automobile manufacturers in the global market. Factors limiting the opportunities of Ukrainian automotive manufacturers are identified, and the consequences of these factors are demonstrated, ultimately leading to the insufficient competitiveness of Ukrainian producers, an inability to scale production, and difficulties in technical upgrading. The results of the article are of interest for shaping the development of the automotive industry in Ukraine.

Conductive Framework Materials for Chemiresistive Detection and Differentiation of Toxic Gases.

ConspectusSensing complex gaseous mixtures and identifying their composition and concentration have the potential to achieve unprecedented improvements in environmental monitoring, medical diagnostics, industrial safety, and the food/agriculture industry. Electronically transduced chemical sensors capable of recognizing and differentiating specific target gases and transducing these chemical stimuli in a portable electronic device offer an opportunity for impact by bridging the utility of chemical information with global wireless connectivity. Among electronically transduced chemical sensors, chemiresistors stand out as particularly promising due to combined features of low-power requirements, room temperature operation, non-line-of-sight detection, high portability, and exceptional modularity. Relying on changes in resistance of a functional material triggered by variations in the surrounding chemical environment, these devices have achieved part-per-billion sensitivities of analytes by employing conductive polymers, graphene, carbon nanotubes (CNTs), metal oxides, metal nanoparticles, metal dichalcogenides, or MXenes as sensing materials. Despite these tremendous developments, the need for stable, selective, and sensitive chemiresistors demands continued innovation in material design in order to operate in complex mixtures with interferents as well as variations in humidity and temperature.To fill existing gaps in sensing capabilities, conductive metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have recently emerged as a promising class of materials for chemiresistive sensing. In contrast to previously reported chemiresistors, these materials offer at least three unique features for gas sensing applications: (i) bottom-up synthesis from molecularly precise precursors that allows for strategic control of material-analyte interactions, (ii) intrinsic conductivity that simultaneously facilitates charge transport and signal transduction under low power requirements, and (iii) high surface area that enables the accessibility of abundant active sites and decontamination of gas streams by coordinating to and, sometimes, detoxifying harmful analytes. Through an emphasis on molecular engineering of structure-property relationships in conductive MOFs and COFs, combined with strategic innovations in device integration strategies and device form factor (i.e., the physical dimensions and design of device components), our group has paved the way to demonstrating the multifunctional utility of these materials in the chemiresistive detection of gases and vapors. Backed by spectroscopic assessment of material-analyte interactions, we illustrated how molecular-level features lead to device performance in detection, filtration, and detoxification of gaseous analytes. By merging the bottom-up synthesis of these materials with device integration, we show the versatility and scalability of using these materials in low-power electronic sensing devices. Taken together, our achievements, combined with the progress spearheaded on this class of materials by other researchers, establish conductive MOFs and COFs as promising multifunctional materials for applications in electronically transduced, portable, low-power sensing devices.

Vegetable growing in Atyrau region: status and prospects

The aim is to substantiate the development of vegetable growing industry in the process of diversification of the economy of Atyrau region. In the methodological aspect, the research on vegetable crops cultivation was carried out on the basis of the deduction method, the consequence of which is the logical conclusion that vegetable production of farms in the region is environmentally safe. Methods of analysis and synthesis were used in determining the competitive parameters of production and the level of its intensification in the period of rising prices for fuels and lubricants. Results - the current state of the vegetable sector of the region, problems and potential opportunities were analyzed, the profitability of the vegetable subcomplex was shown. Recommendations aimed at expanding the scope of management, providing agricultural enterprises with timely and objective information important for making management decisions have been developed. Conclusions - it is necessary to constantly intensify research and development work on the development of new vegetable varieties, their approbation and introduction into practice, which will increase productivity at lower costs. Sectors should pay attention to the quality of vegetable products, their shelf life, useful properties for human health and adaptation to local climatic conditions. The authors note the feasibility of establishing workshops for processing biomass waste and rejected low-grade products. It is concluded that the vegetable market has a high capacity and is characterized by stable demand, which makes it attractive for investment. Investments are the decisive factor of technological, economic and social renewal of economic entities. In dynamics, the innovation activity of agricultural entities is increasing, although it is lower than in the economic system as a whole. The state should become the coordinator of innovation processes in the industry. There are all prerequisites for building up the competitive advantages of the industry.

Optimum power control and coordinate sizing for the stand-alone wind-energy storage integrated hydrogen production system

The stand-alone wind-energy storage integrated hydrogen production technique is becoming a key and emerging technique to achieve carbon neutrality. However, the conflict between the random wind power fluctuation and the stable power demand of the electrolyzer lowers the system's operation stability and reliability. To address this issue, a modified output power smooth control strategy for the wind turbine that considers the dynamic performance of the electrolyzer is proposed. The output power of the wind turbine can be smoothed following the need of the electrolyzer, which helps reduce the electrolyzer's start-stop times and the battery's charging and discharging cycles. Eventually, the efficiency and life span of the hydrogen production system is enhanced. Afterward, an operational strategy for the hydrogen production system is provided, and a coordinated sizing strategy for the wind turbine, energy storage system, and electrolyzer is proposed. The results of case studies, which use the real data obtained from a hydrogen production demonstration project, prove that the overall lifecycle revenue for the hydrogen production system is remarkably increased. Finally, a long-term simulation model for a stand-alone wind-energy storage integrated hydrogen production system was developed. Simulation results validate the effectiveness of the proposed method.

Effective and durable repigmentation for stable vitiligo: A randomized within-subject controlled trial assessing treatment with autologous skin cell suspension transplantation

BackgroundVitiligo lesions are often challenging to repigment with conventional medical therapies. Surgical autologous melanocyte transfer methods can be utilized for stable vitiligo but demand specialized skills and equipment. A point-of-care autologous cell harvesting device was designed enabling simple preparation of autologous skin cell suspension (ASCS) containing melanocytes, keratinocytes, and fibroblasts providing a straightforward approach for cellular transplantation. ObjectiveTo evaluate the safety and effectiveness of ASCS for repigmentation of stable vitiligo lesions among adults. MethodsA US multicenter, randomized, within-subject controlled trial compared ASCS to NB-UVB only (Control) in similar vitiligo lesions. ASCS was applied after laser skin resurfacing and followed by NB-UVB treatment. The primary effectiveness endpoint was the proportion of lesions achieving ≥80% repigmentation at week-24. Repigmentation durability was assessed at week-52. ResultsAmong 25 subjects, 36% of ASCS-treated lesions achieved ≥80% repigmentation at week-24 compared to 0% for Control (p<0.025), with durability through week-52. The safety profile of ASCS was acceptable, with favorable patient- and investigator-reported outcomes. LimitationsStudy sample size limited robust subgroup analyses. ConclusionApplication of ASCS is a safe and effective treatment for repigmentation of stable vitiligo lesions with the potential to improve health-related quality of life and reduce burden of disease.

The effect of hydropower bidding strategy on the iberian day-ahead electricity market

In 2021, the Iberian Electricity Market, which includes Portugal and Spain, experienced a significant increase in electricity prices. On average, prices tripled compared to pre-pandemic levels in 2019, despite stable demand. This trend, though less pronounced in other European markets, has raised concerns about the efficiency and competitiveness of wholesale electricity markets. This study investigates the bidding behavior of non-pumped hydropower plants in the Iberian market, employing a merit order model based on real data from 2019 to 2021. The analysis reveals a clear mismatch between hydropower bid prices and actual production costs. Although this practice is legal, it conflicts with the European Union's goal of promoting fair competition within the internal electricity market.Our findings suggest that aligning hydropower bid prices with 2019 levels could have reduced annual market costs by approximately 2324 million euros under a moderate scenario. This indicates substantial potential for cost savings and improved integration of hydropower. However, this strategy also benefits companies that own these hydropower plants, as they often possess large portfolios and can capitalize on increased market prices through other plants, particularly renewable energy units, which offer electricity at very low prices and have a high likelihood of being dispatched.Furthermore, the study highlights regulatory gaps allowing hydropower plants to price low-cost energy similarly to thermal plants, raising consumer costs and distorting market dynamics. These findings emphasize the need for stronger regulatory oversight and reforms to prevent excessive price inflation by hydropower, which plays a critical role in renewable energy integration and grid stability. Policymakers must ensure fair pricing while compensating hydropower plants for their flexibility and essential contributions to the energy system.

Olympic team rowers and team swimmers show altered functional brain activation during working memory and action inhibition

BackgroundHigh-level expertise in team-sports is associated with superior performance on executive functions (EFs) such as working memory (WM) and action inhibition, and with altered activation of brain areas related to these EFs. In most such studies, athletes were sampled from the domain of dynamic (i.e., open-skill) team-sports (e.g., soccer players). Whether static (i.e., closed-skill) team-sports athletes (e.g., rowers and synchronized swimmers) also show superior EFs performance and differential EF-related functional brain activation remains unknown. MethodsWe recruited 14 elite closed-skill athletes, all national champions, and internationally competitive in various rowing disciplines, as well as 14 controls matched on gender, age, and education, and had them perform working memory and action inhibition (stop-signal) tasks during fMRI scanning. ResultsGroup differences in performance in either task failed to obtain statistical significance, although athletes showed a numerical trend toward higher WM capacity than controls. Importantly, task-related BOLD responses suggested that Olympic closed-skill team athletes show stronger recruitment of brain areas that emphasize relatively stable task demands and weaker engagement of brain areas that emphasize rapidly changing demands imposed by extraneous stimulation. ConclusionFunctional brain imaging data suggest elite closed-skill athletes may employ different cognitive strategies.

Assessing the efficiency of the effect of innovations on the development of grain processing enterprises

This study evaluates the impact of the introduction of deep grain processing on the development of grain processing enterprises. The main problems of processing grain crops in the Republic of Kazakhstan have been considered. The need to assess the impact of the innovative process of enterprise development was outlined. The research was carried out in the North-Kazakhstan region; the object of the study was the grain processing industries in the North-Kazakhstan region. The results show the following: 1) total cost savings when expanding the level of gluten consumption (up to 3 % by weight of the volume of flour consumed) will save USD 18.5 billion. The savings are due to the significant improvement in the baking properties of the flour when adding 1−3 % gluten to the level of the highest quality wheat flour. At the same time, due to the manufacturability of the process and the use of the lowest quality raw materials, the unit cost of gluten in terms of protein is lower than the price of high-quality wheat necessary for baking; 2) in the processing of starch and amino acids, grain starch is the main product of world trade among all goods of the grain processing industry, and gluten ranks only second in terms of world imports. The share of issued patents in the area of starch production is also leading among the sectors of deep grain processing; 3) the implementation of the developed project for deep processing of grain in Northern Kazakhstan could significantly improve the indicators of innovative development of the country: the increase in innovative products of the manufacturing industry in the country as a whole would be 19.1 %. The growth of non-resource exports would equal 1.5 %. The annual increase in the enterprise's revenue could be about USD 0.47 per USD 1 of investment costs compared to the base scenario for the sale of unprocessed wheat. The scope of practical application of the results extends to the grain industry. The project has a significantly wider range of manufactured products and is focused on the markets of neighboring countries, which could reduce export risks to a minimum and provide stable demand for the company’s products

Beyond traditional pathways: Uncovering ultrasonication’s novel routes to enhance hydrogen yields in Clostridium pasteurianum

This study presents a comparative analysis of metabolic end-products and proteomic profiles in Clostridium (C.) pasteurianum during dark fermentation, in the presence and absence of ultrasonication. The study revealed significant changes in the abundance of six proteins associated with dark fermentation pathways, particularly those involved in hydrogen generation pyruvate:ferredoxin oxidoreductase (PFOR) and pyruvate formate lyase (PFL)), glycolysis, butyrate pathway, and adenosine triphosphate (ATP) synthesis. Ultrasonication was efficient at degassing with dissolved hydrogen concentrations reduced from 2.63 ± 0.09 mM to 0.65 ± 0.04 mM. This led to an 11 % increase in produced hydrogen concentration, and a 37 % increase in hydrogen yield. Contrary to expectations, ultrasonication resulted in a deceleration of both glycolytic and hydrogen generation pathways, as evidenced by a decrease in the proteomic expression of key enzymes like pyruvate:ferredoxin oxidoreductase and pyruvate formate lyase. The study also discovered an increased ATP demand and an altered carbon flux through metabolic pathways in C. pasteurianum. This flux initially favoured the acetate pathway due to the sudden ATP demand. The long-term maintenance of this ATP demand required balancing the carbon flux between lactate, acetate, and butyrate pathways, to achieve both a stable redox balance and ATP demand. For the first time, this study revealed opportunities to enhance hydrogen yields using strategies other than enhancing the hydrogen generation pathways, specifically by reducing dissolved hydrogen concentrations.

Prediksi Jumlah Produksi Kelapa Sawit di Indonesia Menggunakan Algoritma Backpropagation

Indonesia is a country that has advantages in the agricultural sector which has the largest plantation and agricultural areas in ASEAN, one of which is oil palm plantations. Indonesia is one of the largest crude palm oil (CPO) business players in the world. More and more palm oil mills and oil palm land are being converted to oil palm cultivation, because oil palm plantations are more beneficial for farmers and palm oil processors. Palm oil plantations are still trying in several ways to maintain stable market demand, one of which is by increasing palm oil production, because palm oil is the main source of other product derivatives. Palm oil production fluctuates every month, but the ups and downs are caused by many factors, namely climate, rainfall, soil fertility, selling prices, and others. Reduced production has a direct impact on the income of farmers and workers in the sector, which in turn can cause economic instability. Actions are needed to ensure the continuity of this industry, one of which is by making predictions. One prediction technique is the Backpropagation artificial neural network. The prediction model can provide very accurate estimates of palm oil production at the provincial level. By analyzing historical data, this research can identify patterns that can help predict future palm oil production. The urgency lies in the strategic role of palm oil in the Indonesian economy.

Capacity optimization of a large-scale photovoltaic power generation system coupled with hydrogen production and storage based on economic analysis

Abstract The renewable energy system coupled with hydrogen storage has proven to be a suitable method to reduce the variability of output power and meet stable hydrogen supply demand. However, the excessive cost of hydrogen through water electrolysis using renewable energy restricts its application, and the capacity configuration of electrolyzers and gaseous hydrogen storage tanks is affected by the immoderate reliance on engineering experience, leading to the unbalance of generation side and hydrogen demand side. In this study, a 300 MW photovoltaic power generation system has been proposed to fit the raw material demand of a synthetic ammonia plant, i.e., around 1000 kg/h hydrogen. A simplified mathematical model including an electrolyzer and a hydrogen tank is proposed to get the best capacity configuration. The levelized cost of hydrogen (LCOH) is chosen as an optimization function, and a particle swarm optimization algorithm is adopted to get the optimal results. The simulation results indicate that the optimal capacity configuration is 176.36 MW for the electrolyzer and 14644.2 Nm3 for the hydrogen tank, and the LCOH is 30.31 Yuan/kg. Compared with the empirical model, the LCOH based on the optimization model is 8.87% lower than that of the empirical model, indicating better economic benefits of the optimization model.

Enhancement of membrane filtration performance and mitigation of sludge calcification in an intermittent anaerobic membrane bioreactor treating high-calcium wastewater

Anaerobic membrane bioreactors (AnMBRs) can alleviate the inhibitory effect of sludge calcification on anaerobic process when treating high-calcium wastewater. However, sludge calcification induced by high-calcium wastewater and flocculated sludge formation under reactor aeration shear will inhibit membrane filtration performance. In this study, an intermittently operated AnMBR (A2) was used to treat high-calcium wastewater, and continuously operated AnMBR (A1) was used as the parallel control. When treating 200–1000 mg/L calcium ion wastewater, A2 achieved a stable chemical oxygen demand removal efficiency of 91.8±3.9 %. The methane production of A2 was 188.2±22.5 mL/(gVSS⋅d), which was marginally higher than the continuous AnMBR (A1) methane production of 174.7±11.7 mL/(gVSS⋅d). Analysis of the microbial community demonstrated significant enrichment in hydrolyzing acidifying bacteria and archaea in A2, compared to A1, which played a crucial role in improving the performance of anaerobic process. A1 exhibited a maximum transmembrane pressure (TMP) of 19.6 kPa, and scanning electron microscopy (SEM) analysis revealed the deterioration of membrane fouling due to sludge calcification on the membrane surface. Surprisingly, the maximum TMP of A2 was just 3.6 kPa during the study. When treating 1000 mg/L of high calcium wastewater, the average effluent calcium concentration in A2 was 650 mg/L, which indicated that A2 effectively retained calcium ions. SEM analysis revealed that anaerobic sludge had a tendency to agglomerate, which slowed down membrane fouling in A2. Sludge agglomeration was due to intermittent operation effectively increasing the contact time of sludge with calcium ions, thereby stimulating the protein secretion of extracellular polymers. These results showed that the intermittent operation effectively mitigated membrane fouling. This work provides a new strategy for comprehensively addressing the challenges of high-calcium wastewater and achieving the stable performance of anaerobic reactors.

One Method for Predicting Satellite Communication Terminal Service Demands Based on Artificial Intelligence Algorithms

This paper presents a traffic demand prediction method based on deep learning algorithms, aiming to address the dynamic traffic demands in satellite communication and enhance resource management efficiency. Integrating Seq2Seq and LSTM networks, the method improves prediction accuracy and applicability, especially for mobile terminals such as aviation and maritime ones. Unlike traditional approaches, it does not require extensive statistical data and can be generalized to real-world systems, providing stable long-term traffic demand predictions. This study utilizes real-world flight data mapped to corresponding satellite beams, allowing the precise prediction of beam-specific traffic demands. The results show that aggregating historical demand data for beams with similar trends achieves an average predictive Mean Squared Error (MSE) of 0.0007 and a maximum MSE fluctuation of 0.014, significantly outperforming predictions based on average values in terms of stability and accuracy. This novel solution for resource management in satellite communication ensures efficient and accurate long-term traffic demand predictions.

The Demand for Real Money Balances in Zimbabwe: An Error Correction Estimation

Purpose: The purpose of the study is to examine the stability of the money demand function in Zimbabwe. Understanding, the money demand function is a prerequisite for effective monetary policy formulation and understanding the monetary transmission process and shocks propagation in the economy. Materials and Methods: The study employs the error correction modeling methodology to investigate the money demand function for Zimbabwe using quarterly data from 2017q2 – 2023q2. The analysis is expanded to characterize the monetary transmission mechanism following a shock to the price level and how the demand for real money balances responds to both single period and multiple shocks. Findings: The findings confirm a stable long run money demand function that is subject to short run dynamics. In addition, real money demand responds positively to real GDP (Scale factor) and inversely related to the price level (inflation). Short term dynamics (particularly inflation expectations) compound real money demand collapse in response to rising inflation. Implications to Theory, Practice and Policy: Monetary Policy must aim to collapse inflation expectations through a tight monetary control program and a functioning interbank market for foreign exchange to avoid surging parallel market activity.

Strategy-based optimization and life cycle environmental impact assessment of a stable photovoltaic power-to-hydrogen system

With the growing global emphasis on reducing greenhouse gas emissions and transitioning to a low-carbon economy, renewable hydrogen is expected to play a vital role in the chemical industry. However, there is a contradiction between the continuous and stable hydrogen demand of chemical process systems and the intermittent and fluctuating nature of renewable energy systems when coupling them together in the industrial chemical production. There are currently few studies addressing year-round stable hydrogen load systems while considering renewable energy intermittency and capacity optimization. Moreover, the comprehensive life cycle environmental impact study of such stable renewable-hydrogen production system is extremely limited. Therefore, this study focuses on a photovoltaic power-to-hydrogen system that can operate stably for 8,760 h per year, specifically targeting its application in the chemical industry. Two operating strategies of the hydrogen system were considered: fully off-grid and ultra-light grid-connected scenarios. The capacity configuration under each scenario was optimized using gird search algorithm, with the objective of minimizing the levelized cost of hydrogen. Based on the optimization results, the energy flow network, cost-effectiveness, and comprehensive life cycle environmental impacts of such system were analyzed. The results show that the ultra-light grid-connected hydrogen production system, due to the support of the power grid, has improved the reliability of the hydrogen production system and significantly reduced the capacity configuration of system components, thereby demonstrating better performance in terms of economics and overall lifecycle environmental impact compared to a completely off-grid hydrogen production system. Its global warming potential (GWP) and levelized cost of hydrogen under electricity sales scenario are 12% and 31% lower, respectively, compared to fully off-grid hydrogen production. Considering China’s future demand for large-scale renewable hydrogen, ultra-light grid-connected hydrogen production may become the primary transitional pathway in the near to medium term.

Operational characteristics of an integrated island energy system based on multi-energy complementarity

This study addresses the intermittent renewable energy supply and the large footprint of battery storage on an island reef in China by proposing an integrated energy system that incorporates hydrogen production, storage, and utilisation. Mathematical models for wind and photovoltaic power generation, energy storage, hydrogen production and utilisation, diesel generators, and energy management systems are established. Additionally, an integrated energy system is constructed using Simulink software to simulate and analyse its operational characteristics in various seasonal scenarios. The simulation results indicate that the surplus from wind power and photovoltaic systems, after supplying the load for over 70 % of the day, constitutes more than 40 % of the load demand. The energy storage system can maintain a maximum charging rate for more than 50 % of the day and a maximum discharge rate for less than 16.7 % of the day. The electrolysis tank produces hydrogen for more than 71 % of the day and simultaneously consumes up to 750 % of the load. The fuel cell consumes hydrogen for less than 12.5 % of the day and simultaneously provides up to 27 % of the load. Analysis revealed that the hydrogen system improves the energy utilisation, the control strategy realises stable supply and demand within the system.

ORGANIZATION AND ANALYSIS OF PRODUCTION EFFICIENCY HORSE BREEDING PRODUCTS BY BREED AND REGION OF THE REPUBLIC OF KAZAKHSTAN

The system of remuneration for workers in productive horse breeding currently provides for a direct relationship between the level of wages and the quality of the products obtained. In the context of the practical implementation of on-farm self-accounting in herd horse breeding, the form of an annual self-accounting task has proven itself well. In the near future, as the current economic situation changes and a stable demand for high-quality, environmentally friendly horse meat emerges, highly productive horse genotypes, preserved and propagated in breeding farms in various regions, will find wide application, both in purebred breeding and for use in various crossbreeding options.

Visiting Friends and Relatives Travel: Unveiling Hidden Drivers Behind Festival Attendance and Experience

This research note unveils a pivotal, yet underexplored, aspect of festival attendance: the impact of visiting friends and relatives (VFR) travel. Employing data from a 2019 attendee survey at the Taste of Little Italy Festival, Toronto, it reveals that 23.3% of respondents were engaged in VFR travel, exhibiting higher spending, yet often providing lower evaluations of their festival experience. The nuanced relationship between VFR travel, spending patterns, and festival experience opens a new avenue for exploration for festival researchers and practitioners. This note aims to encourage festival researchers and practitioners to consider the implications of VFR. A more comprehensive understanding of this topic could reveal strategies to engage this stable demand source, influencing not only event management strategies but also enhancing cultural engagement and community attachment. The note underscores the opportunity for festivals to engage residents and their visitors to optimize both economic and experiential outcomes.

Analysis of the Dairy Milk Supply Chain at Sapi Juara Farm, Bogor Regency

Pamijahan District in Bogor Regency, West Java, is known as one of the main sources of milk supply for dairy cows in the region. Dairy cow's milk is a product that has high and stable demand and selling value. Supply Chain Management (SCM) at Sapi Juara Farm in Pamijahan District involves the distribution of dairy cow's milk which includes product flow, information and finance. This study aims to understand the SCM of dairy milk at Sapi Juara Farm, including product flow, information and finance, as well as efficiency as measured through marketing margin and farmer's share. This research uses quantitative descriptive methods with primary data obtained from interviews. The results of the analysis show that there is a flow of dairy milk products, a flow of information from farmers to various actors in the supply chain, and a flow of funds that includes costs and profits from nine distribution channels that influence the performance of the supply chain based on the payment system. From the analysis of the profit share value, it can be seen that the SCM for dairy cow milk in Pamijahan District is running efficiently. It is hoped that SCM in Pamijahan District can be more efficient to avoid losses at each stage or link in the chain and stabilize milk prices in the market, while improving the welfare of farmers, especially at Sapi Juara Farm.