Main Energy Source Research Articles

Stream food webs in tropical mountains rely on allochthonous carbon regardless of land use

The relative importance of allochthonous and autochthonous carbon (C) as sources of energy for tropical stream food webs remains an open question. Allochthonous C might be the main energy source for small and shaded forest streams, while autochthonous C is more likely to fuel food webs draining land uses with less dense vegetation. We studied food webs in cloud forest streams draining watersheds with forests, coffee plantations, and pastures. Our goal was to assess the effects of those land uses on the C source and structure of stream food webs. The study took place in tropical montane streams in La Antigua Watershed, in eastern Mexico. We selected three streams per land use and sampled biofilm and leaf litter as the main food resources, and macroinvertebrates and aquatic vertebrates from different trophic guilds. Samples were analyzed for δ13C and δ15N isotopes. Using a Bayesian mixing model, we estimated the proportional assimilation of autochthonous and allochthonous carbon by each guild. We found that consumers were mostly using allochthonous C in all streams, regardless of watershed land use. Our findings indicate that montane cloud forest streams are dominated by allochthony even in watersheds dominated by pastures. Abundant precipitation in this life zone might facilitate the movement of allochthonous C into streams. While food webs of streams from coffee plantations and pastures also rely on allochthonous resources, other impacts do result in important changes in stream functioning.

The potential mechanism of response to light intensity in energy metabolism mediated by miRNA in Isatis indigotica

Light is the main source of energy for plant growth. Studies have shown that I. indigotica is a light-demanding plant and its yield and various active components are positively correlated with light intensity, but no studies of light intensity affecting energy metabolism in I. indigotica have been reported. Mitochondria are the main site of energy metabolism, and miRNAs are important factors in regulating gene expression, this experiment attempts to study the effects of different light intensities on energy metabolism from the perspective of mitochondria and miRNAs. The results show that the biomass、mitochondrial structural integrity and energy metabolism in I. indigotica were found to be positively correlated with light intensity. Small RNA and transcriptome sequencing identified 241 miRNAs and 36,372 mRNAs, and degradomic technology identified 72 miRNAs targeting 106 mRNAs, among which 12 pairs of miRNA-mRNAs were annotated on mitochondria. Combined with RT-qPCR validation, it was concluded that miR167a-5p positively regulates LETM1 and affects mitochondrial structure, miR400-5p and mIR169m-p3_1ss15CT negatively regulate GRXS15 and CMC4, respectively, affecting SDH and CCO activities, and miR395a-APS4 may affect the utilization of ATP and sulfate assimilation. In summary, the results of this study complement and enrich knowledge of light effects on mitochondria from the perspective of miRNA, while providing guidance for the cultivation of I. indigotica.

METHODS OF INVESTIGATING GAS LEAKS IN PIPELINE BELTS

The use of combustible gases in household and industry began in the past centuries. By processing coal, methane and other gas mixtures contained in it were obtained. For the first time, this method was used in England in the 19th century. A large number of plants have started operating, which realized the purchase. This processed gas was used to burn large furnaces and relatively heat houses. Over the years, people began to use natural gas as a fuel and its use became more and more widespread. Already in the middle of the 20th century, along with other combustible gases, natural gas began to be used in industry and household. Historical sources show that the most use of natural gas was in the United States. The reason for this is the discovery of large gas fields in the country. The history of the beginning of the gas industry in the United States The year 1831 is considered. Later, the wide consumption of natural gas in the pipe-laying industry and in households began here. Wide use of natural gas in Azerbaijan began in the middle of the 19th century. Natural gas was used as a fuel for the first time in 1859 in a factory operating in Surakhani. Gas energy is the main source of energy used in many home and industrial applications. However, gas leaks can pose serious hazards. Timely detection and repair of gas leaks play an important role in preventing dangerous situations such as fire, explosion and poisoning. In this article, we will focus on the methods used to investigate gas leaks. The article examines and analyzes the types of gas leak detection. The main goal of selecting automatic systems in gas pipelines and their analysis is to detect gas leaks and accurately control gas consumption. The article analyzes the following methods of monitoring gas leaks in a gas pipeline: Volume balance method, gas movement time-varying pressure drop method, acoustic emission method, ultrasound method and pressure profile method. Each of these methods has advantages and disadvantages. The results of the application of all the considered methods vary depending on the parameters of the external environment. The parameters of the external environment can be given as an example of temperature, density and pressure. The main task of the proposed methods is the accuracy of the measurement results in the changing parameters of the external environment. Let's consider modern methods of detecting gas leaks in pipelines. Two main methods have been developed for locating gas leaks: visual and instrumental methods. Special attention is also paid to one of the most common automatic gas analyzers - gas sensors. Keywords: Gas leak detection, automatic gas analyzers, pipelines, gas leak monitoring, gas sensors.

Evaluation of wave energy converters based on integrated ELECTRE approach

The demand for renewable energy sources is growing rapidly as a result of increasing energy consumption, fossil fuel depletion, climate change, and environmental degradation. The tide is one of the main sources of renewable energy in the ocean because of its huge potential to be harnessed. Wave-energy converters (WECs) are a potential alternative to present energy sources, with an emphasis on improving efficiency and increasing energy. With the goal of improving the uncertainty inherent in data representation, the literature gradually uses various fuzzy extensions that handle fuzzy information in subjective evaluations and decision-making processes. single-valued neutrosophic probabilistic hesitant fuzzy sets (SVNPHFS), a recent extension of neutrosophic fuzzy sets, address limitations associated with membership functions and the representation of hesitancy in multi-criteria decision-making (MCDM) approaches. In the decision-making process, uncertainty is successfully handled by SVNPHFS. The objective of this study is to investigate and select a potential converter for a WEC power plant using SVNPHFS. Seven criteria for WECs are selected as potential sites for establishing a wave-energy power plant. The paper proposes a novel hybrid MCDM methodology. Fuzzy SWARA (Stepwise Weighted Assessment Ratio Analysis) is utilized for assigning weights to the criteria for WEC selection, and fuzzy ELECTRE (Elimination and Choice Expressing Reality) is used to determine the most suitable alternative using these criteria weights. The proposed technique identifies the point absorber in the first rank for the best wave-to-energy converter power plant as it generates a high amount of electricity compared to other alternatives. The result shows that the proposed model is more robust compared to other approaches.

Effects of Faidherbia Albida (Del.) Chev. Torrefied Pods on the Zootechnical Performances of Laying Chickens

Introduction: The cost of poultry feed directly impacts production yield. The search for feed formulations based on less expensive products is, therefore, an alternative to improve the profits of producers. This study was conducted in Maradi at the Regional Center for Agronomic Research of the National Institute of Agronomic Research of Niger to assess the effect of roasted Faidherbia albida pods on the zootechnical performance of Isa Brown laying chickens. Materials and methods: A total of 200 Isa Brown laying chickens, aged 21 weeks, were randomly assigned to four feeding groups with five replicates each. The chickens were housed in a 5 m × 10 m building, with 10 chickens per replicate in blocks of 1.71 m². The building featured ventilation, natural lighting, and bedding made from peanut shells. Apart from the control feed (F0), the experimental feeds contained 5% (F5), 10% (F10), and 15% (F15) crushed pods of Faidherbia albida roasted at 110°C. Millet and wheat bran were the main energy sources, while fishmeal and groundnut cake provided protein. Water was provided ad libitum to all chickens. The feed was distributed over 2 months. Results: The results showed that feed ingestion increased significantly with F10 compared to the control, while consumption remained comparable among the control, F15, and F5 groups. The incorporation of roasted Faidherbia albida pods led to a significant decrease in the feed conversion ratio, with a significant difference among the treatments. The best feed conversion ratio was obtained with the F5 ration, followed by the F0 control. Conclusion: The inclusion of Faidherbia albida in the diet of chickens is beneficial for egg production. The optimal incorporation rate for roasted pods of Faidherbia albida was determined to be 10%.

Voltage and frequency control of solar – battery – diesel based islanded microgrid

Abstract Islanded microgrids with low-inertia distributed energy resources (DERs) are prone to frequency fluctuations. With the increasing integration of DERs in microgrids, the complexity of control and stability has also increased. Moreover, the integration of DERs into microgrids may result in a power imbalance between energy supply and demand during sudden changes in load or energy generation. This can cause frequency variations in the microgrid, which could have disastrous consequences such as equipment damage or even blackouts. This paper proposes a control strategy to ensure the efficient operation of an islanded hybrid microgrid consisting of a PV generator, battery energy storage system (BESS), and emergency diesel generator. According to Energy Exchange Model proposed in this paper, the hybrid system presented operates independently without being connected to the electrical grid, where the PV system and BESS act as the main energy sources, while the emergency diesel generator provides active power backup with voltage and frequency regulation. The novel in this paper is also that DER aids in frequency regulation during active power transients by delivering and absorbing active power in accordance with the inverter's suggested P droop control strategy. In this way inverter droop control decreases system frequency nadir emulating so called “synthetic inertia”. To design both the islanded hybrid system and the proposed control strategy, the MATLAB/Simulink environment is utilized. Based on the results, it can be concluded that the analyzed microgrid system is capable of maintaining stability and operating efficiently in a range of operating conditions.

The effectiveness of alkaline and thermo hydrolysis pretreatments in the bioethanol production from Calliandra calothyrsus wood

The demand in energy is increasing along with the development of technology. However, the utilization of fossil energy as the main current energy sources creates various environmental problems. Hence, it is important to search other energy sources which are environmentally friendly. One of the renewable energy sources is bioethanol produced from woody biomass. The purpose of this study was to investigate the suitability of Calliandra calothyrsus wood under development of alkaline and thermohydrolisis pretreatments. These pretreatments included the variations of 15, 30, 45 and 60 min at 121°C with NaOH concentration of 1, 2, and 3% (w/v). The chemical component analysis was conducted by using the TAPPI method, while the percentage of reducing sugar after saccharification was carried out by the Nelson-Somogy method. The results showed that the highest holocellulose content 60,62%, and the highest α-cellulose content was 64,30%. The highest pulp saccharification test results were obtained from 60 min pretreatment of 3% concentration of NaOH, which was 42,82% and 32,99% wood basis. The highest yield of ethanol potential was obtained from 36 hours saccharification, which was 139 L/Ton. Finally, it is suggested to do additional treatments with variations in concentration and temperature in order to obtain more optimal results.

Кореляційні зв’язки між функціональним станом організму та конституційними характеристиками складу маси тіла юнаків гірських районів Закарпаття

Aerobic and anaerobic productivity of the body are integral indicators of physical health. assessment of physical health based on indicators of aerobic and anaerobic productivity makes it possible to characterize it not only qualitatively, but also quantitatively [3]. The ability to demonstrate aerobic capabilities largely depends on the content of muscles, which are the main consumer of oxygen in the body [10]. Fat does the role of a regulator of metabolic processes in the body and is the main source of energy during long-term work of low intensity, which is performed due to aerobic energy supply mechanisms of muscle activity. To clarify the degree of influence of somatotype components and components of body weight on the functional capabilities of young men living in the mountainous districts of Zakarpattia, we conducted a correlation analysis. Researches was conducted in 124 young men of the post-puberty period of ontogenesis aged 17 to 21 years, residents of the mountainous districts of the Zakarpattia region. Physical health status was assessed by indicators of the aerobic productivity of the body, namely, the maximum oxygen consumption was measured (VО 2 max ) using the bicycle ergometry method. To evaluate the level of aerobic productivity, the Ya. P. Pyarnat’s rating scale was used [14]. Indicators of anaerobic productivity of the body were studied by: measuring the power of anaerobic alactic energy supply processes by the Peak Power Output in 10 s (WAnT 10 ); the power of anaerobic lactic energy supply processes by the Peak Power Output in 30 s (WAnT 30 ), using the Wingate anaerobic test described by Yu. M. Furman et al. [15]. The anaerobic lactic productivity of the organism was measured by the Peak Power Output (PPO) in 1 min using A. Shogy and G. Cherebetin’s method [16]. The component body mass composition was determined using the impedance method with the application of Somatotype was determined by the Heath-Carter method, which provides a three-component (fat, muscle and bone) anthropometric assessment [17]. Omron BF511 Body Composition Monitor to estimate the percentage of fat mass (subcutaneous and visceral fat) and the percentage of skeletal muscle [18]. The statistical processing of the material was carried out in Excel 7.0 and SPSS version 10.0 using Student’s t-test to find out the reliability of the difference between the average values. In young men, divided by somatotype, it was established that in representatives of the endomesomorphic somatotype, higher values of the fat component largely cause lower values of VO 2 max rel. to (r = -0.706; p < 0.001), correspondingly lower level of aerobic performance. Higher values of BMI in young men of endomesomorphic and mesomorphic somatotypes cause higher values of the absolute VO2 max indicator, as indicated by the correlation (r = 0.727; p < 0.001 and r = 0.880; p < 0.001, respectively). The degree of development of the components of the somatotype does not have a significant impact on the aerobic performance of young men of different morphological types, which is confirmed by a correlation that does not exceed the average degree. Among young men of different somatotypes, there is no correlation of body composition, BMI with the power of anaerobic lactate energy supply processes, or the strength of the connection does not exceed the average. It was found that higher BMI values significantly cause a higher level of anaerobic lactate productivity of the body only in representatives of the endomesomorphic somatotype, as indicated by a strong direct correlation (r = 0.740; p < 0.001) with the WAnT30 absolute indicator. A strong negative influence of percentage fat content in the body on the capacity of the anaerobic lactate productivity of the body in young men of the mesoectomorphic somatotype, which is evidenced by negative correlation (r = -0.445; p > 0.05) with the PPO rel. Higher values of BMI cause a lower level of anaerobic lactate productivity of the body in young men mesoectomorphic and endomesomorphic somatotypes, which is confirmed by a strong negative correlation with the PPO rel. (r = -0.594, p < 0.01; r = -0.430, p < 0.01 respectively). In addition, in young men of the endomesomorphic somatotype, higher values of BMI cause higher values of the absolute index of PPO (r = 0.628; p < 0,001).

Fiscal Policies Promote the Development and Popularization of Green Electricity

The concept of carbon neutrality is constantly being improved and various carbon neutral project technologies are constantly being developed. Under the current "double carbon" background, green power, as an emerging energy industry, is gradually developing into one of the main clean energy sources in the future. However, as the operation and management system of green power is gradually being improved, its various application fields and its popularization to the public still need to be studied. Through the investigation and research of green power, the analysis of financial policies and the test of the acceptable range of the public, analysis Organize solutions that can promote the use and development of green electricity in current trends in fiscal policies.

Carbon Emission Intensity and Its Abatement Choices: A Case of China Eastern

Air transportation, which is a derived demand, is booming following the rapid development of the world economy, and carbon emissions from the air transportation industry, which takes fossil fuels as its main energy source, have been increasing. Therefore, with global warming attracting considerable attention, the issue of how to reduce carbon emissions from air transportation has become a hot issue. We take China Eastern Airlines Corporation Limited (China Eastern) as an example to analyze the main factors influencing airlines’ carbon emissions, specifically around the impact of airline internal operating indicators, such as available seat kilometers (ASK), passenger load factor (PLF), fuel consumption per unit passenger kilometer, the average age of operated aircraft, on-time performance (OTP), etc. This paper uses a correlation analysis, panel regression analysis, and other ways to explore the influence mechanism of the above factors on carbon emission intensity. The conclusions for China Eastern are the following: first, PLF has a significant negative relationship with carbon emission intensity; second, fuel consumption per passenger kilometer has a significant negative relationship with carbon emission intensity. Third, OTP has a significant positive relationship with carbon emission intensity. Fourth, fleet size has a significant positive relationship with carbon emission intensity. Finally, we propose several targeted carbon abatement measures for China Eastern, such as improving PLF and OTP, reducing fuel consumption per unit passenger kilometer, speeding up fleet renewal, etc.

Oil and Gas Sector of the People’s Republic of China: Problems and Development Trends

Through vigorous economic development in recent decades, China has become one of the world’s leading economies and a major player in the international arena. The strengthening economic potential has caused a significant increase in the demand for energy resources. Therefore, the need for an effective energy policy has also increased. The PRC uses fossil energy resources such as coal, oil and natural gas as its main energy sources. Fossil energy sources are currently important for maintaining the country’s energy balance. Moreover, one of the important objectives of energy policy is to reduce the environmental risks associated with the overuse of the coal industry. The coal industry poses a serious threat to the environment, as emissions of biogenic methane and carbon dioxide from fuel combustion lead to a greenhouse effect. In this regard, China is actively developing alternative energy sources that will be beneficial for this period of economic development, namely the oil and gas industry. Oil and gas are among the main sources of energy in the PRC today. China currently occupies an important position in the global oil and gas market, having a significant impact on prices in these sectors. Every year, the country purchases significant amounts of oil and gas from global markets and uses them in various sectors of the economy, including manufacturing, transport and energy. In addition, China is actively developing oil and gas infrastructure and investing in exploration and production activities to meet its own energy needs. In this regard, the article studies the oil and gas industry of the PRC, considers the main indicators of oil and gas production, imports and consumption, and analyses the existing development trends and problems of this industry.

Low-carbon economic multi-objective dispatch of integrated energy system considering the price fluctuation of natural gas and carbon emission accounting

Natural gas is the main energy source and carbon emission source of integrated energy systems (IES). In existing studies, the price of natural gas is generally fixed, and the impact of price fluctuation which may be brought by future liberalization of the terminal side of the natural gas market on the IES is rarely considered. This paper constructs a natural gas price fluctuation model based on particle swarm optimization (PSO) and Dynamic Bayesian networks (DBN) algorithms. It uses the improved epsilon constraint method and fuzzy multi-weight technology to solve the Pareto frontier set considering the system operation cost and carbon emission. The system operation cost is described using Latin Hypercube Sampling (LHS) to predict the stochastic output of the renewable energy source, and a penalty function based on the Predicted Mean Vote (PMV) model to describe the thermal comfort of the user. This is analyzed using the Grey Wolf Optimization (GWO) algorithm. Carbon emissions are calculated using the carbon accounting method, and a ladder penalty mechanism is introduced to define the carbon trading price. Results of the comparison illustrate that the Pareto optimal solution tends to choose less carbon emission, electricity is more economical, and gas is less carbon-intensive in a small IES for end-users when the price of natural gas fluctuates. The impacts of various extents of natural gas price fluctuation for the same load are also discussed.

The value of tropical forests to hydropower

Tropical forests have a significant impact on rainfall patterns at a continental scale, thereby influencing water supply for energy generation of hydropower plants. I develop a method to value this ecosystem service using an econometric climate model that connects tropical deforestation with rainfall. As an application, I estimate the impact that Amazon deforestation has on the power generation capacity of the Teles Pires hydropower plant in Brazil, one of the ten largest plants in a country where hydropower is the main source of energy. In an ex-post analysis, I map the currently deforested regions in the Amazon with the highest restoration values for the hydroelectric. In an ex-ante analysis, I map the potential cost of deforesting Indigenous Territories. The results provide evidence of the importance of the ecosystem services of tropical forests to the energy sector.

THE POTENTIAL USE OF MINI WIND TURBINES AT SEKOLAH TINGGI ILMU PELAYARAN AS AN ALTERNATIVE RENEWABLE ELECTRICAL ENERGY SOURCE

The need for electrical energy from year to year is getting bigger along with the increasing growth of population and industry, especially in big cities in Indonesia. The need for electrical energy in Indonesia still depends on Electrical Energy provided by the Perusahaan Listrik Negara (PLN). the main source of PLN's electrical energy is Fuel oil and Coal (50.01%). Sekolah Tinggi Ilmu Pelayaran as an educational institution seeks to support the government to reduce dependence on electrical energy produced with fossil fuels by seeking the potential of electrical energy sourced from renewable energy sources. One of the energies that has the potential as alternative energy is wind energy, where kinetic energy from the wind is utilized into electrical energy using wind turbines. For this reason, it is necessary to calculate the potential of wind energy as a renewable alternative energy at Sekolah Tinggi Ilmu Pelayaran

Comparative analysis of kinetic realizations of insulin signaling

Several studies have developed dynamical models to understand the underlying mechanisms of insulin signaling, a signaling cascade that leads to the translocation of glucose, the human body’s main source of energy. Fortunately, reaction network analysis allows us to extract properties of dynamical systems without depending on their model parameter values. This study focuses on the comparison of insulin signaling in healthy state (INSMS or INSulin Metabolic Signaling) and in type 2 diabetes (INRES or INsulin RESistance) using reaction network analysis. The analysis uses network decomposition to identify the different subsystems involved in insulin signaling (e.g., insulin receptor binding and recycling, GLUT4 translocation, and ERK signaling pathway, among others). Furthermore, results show that INSMS and INRES are similar with respect to some network, structo-kinetic, and kinetic properties. Their differences, however, provide insights into what happens when insulin resistance occurs. First, the variation in the number of species involved in INSMS and INRES suggests that when irregularities occur in the insulin signaling pathway, other complexes (and, hence, other processes) get involved, characterizing insulin resistance. Second, the loss of concordance exhibited by INRES suggests less restrictive interplay between the species involved in insulin signaling, leading to unusual activities in the signaling cascade. Lastly, GLUT4 losing its absolute concentration robustness in INRES may signify that the transporter has lost its reliability in shuttling glucose to the cell, inhibiting efficient cellular energy production. This study also suggests possible applications of the equilibria parametrization and network decomposition, resulting from the analysis, to potentially establish absolute concentration robustness in a species.

Adoption of Agroforestry as a Climate Smart Agriculture Practice among Smallholder Farmers in Kakamega County, Kenya

Climate Smart Agriculture (CSA) technologies help guide actions needed to transform and reorient agricultural systems to effectively support development and ensure food security by increasing farmers’ resilience to climate change. Agroforestry has been vouched for as one of the best CSAs because it provides ecosystem services such as water quality enhancement and prevents land degradation. This study sought to establish and document the adoption of agroforestry as a CSA practice among smallholder farmers in Kakamega County. Stratified sampling was used to select six sub-counties to represent the county's various agroecological zones and regions for the research sample. A combination of purposive and snowball sampling was used to select 428 smallholder CSA farmers, of whom 376 (87.9%) were practicing agroforestry. Primary data was collected using interview guides developed through the Kobo Collect application. Microsoft Excel and Statistical Package for Social Sciences (SPSS) statistical packages were used to process and analyze the data. This study found that wood fuel was the main source of energy for 73% of the smallholder agroforestry farmers, followed by solar energy devices (12%), charcoal (7%), electricity (6%), and kerosene (2%). Grevillea Robusta was the most widely preferred agroforestry tree variety, adopted by 91.8% of agroforestry smallholder farmers, followed by fruit trees (73.4%), blue gums (67.3%), Cyprus (34.0%), and Calliandra (37.5%). Fodder tree types such as Sesbania and Casuarina were adopted by 30.9% and 23.9% of the smallholder agroforestry farmers, respectively. This study recommends the integration of agroforestry into farming systems by incentivizing farmers through programs like tree planting, free seedlings, and farm competitions. School agricultural clubs, such as 4K clubs for primary schools and Young Farmers Clubs for secondary schools, could be motivated and supported to use school gardens for food and fruit tree production. This study also recommends the promotion of modern stoves (maendeleo jikos), which use less wood fuel, are more efficient in cooking, and also reduce GHG emissions.

Thermal Study of the Utilization of Rice Husks Using the Forced Convection Method as Energy for a Rotating Cylinder Dryer

Small farmers in rural areas use the sun as their main energy source to dry post-harvest products. Due to limited knowledge and technology, farmers depend on the sun through direct drying. Direct use of the sun for the drying process has disadvantages in uncertain weather such as cloudy or rainy. This results in the drying process not being optimal or even stopping. This research aims to use rice husks as energy to replace direct sun drying to produce optimal temperatures so that drying time is shorter and the quality of the dried food is hygienic. Rice husk as an energy source is applied through a rotating cylinder dryer. This dryer is tailored to farmers' needs, namely easy to operate at an affordable price. This energy can be utilized sustainably because it is abundant through a forced convection system and energy conversion using a heat exchanger. The design of the compact rotary dryer includes an integrated drying chamber in one unit with the combustion furnace and a heat exchanger. The drying chamber includes a rotating cylinder and a fixed cylinder. The test results show that hot air from burning rice husks flows through the heat exchange pipes by conduction from the furnace to the walls of the drying chamber and by forced convection through an exhaust fan installed in the drying chamber. The average environmental temperature of 29.55-29.69oC has increased when using one exhaust fan to 64.46oC and two exhaust fans to 60.11oC. This drying temperature can produce shorter drying times, so it can be applied to post-harvest product drying, which is energy-efficient and sustainable for small farmers. Based on research results, rotating cylinder dryers powered by rice husks are very suitable for small farmers to replace direct sun drying.

International law and transboundary dams: lessons learned from the Binational Entity ITAIPU (Brazil and Paraguay)

The international river Paraná flows through Brazil, Paraguay and Argentina, and holds two major binational dams: the upstream ITAIPU dam (Brazil-Paraguay) and the downstream Yacyreta dam (Argentina-Paraguay). In the past years, the South American region was strongly affected by adverse environmental challenges exacerbated by climate change, like wildfires and severe droughts, which in turn drastically affected the water flow of the Paraná river, a river used for multiple purposes, inter alia the production of energy. The hydropower obtained from ITAIPU is one of the main sources of energy for Paraguay and the Southern part of Brazil. At the same time, the downstream parts of the river is used for navigation purposes, which is crucial for land-locked Paraguay to export its agricultural products, and for water consumption, as is the case for Argentina. The present case study will show how in spite of these challenges, South America has been an successful example of transboundary water cooperation, especially by using the international water law guidelines aimed at achieving reasonable and equitable utilization of an international river.

Approach to Modernizing Residential-Dominated District Heating Systems to Enhance Their Flexibility, Energy Efficiency, and Environmental Friendliness

The need to modernize existing district heating systems is due to increased requirements for their flexibility, energy efficiency, and environmental friendliness. The technical policy on district heating pursued in different countries centers on the listed goals and takes account of historical, climatic, and regional features of the resource, technology, and economic availability of various thermal energy sources. This study aims to analyze methods designed to improve the flexibility, energy efficiency, and environmental friendliness of district heating systems. The focus of the study is district heating system, which provides heating and hot water supply to consumers and consists of various types of thermal energy sources. The work shows the possibility for the heating system to transition from the third generation to the fourth one, which differ in their level of intellectualization. The establishment of an intelligent control system will ensure the interaction of various heat sources, but this is a separate strand of research. In this study, a model and a methodology were developed to optimize the structure of thermal energy sources and their operating conditions when covering the heat load curve of a territory with a predominance of household consumers. Gas-reciprocating and gas-turbine cogeneration plants are considered as the main thermal energy sources, whose efficiency is boosted through their joint operation with electric boilers, thermal energy storage systems, low-grade heat sources, and absorption chillers. The primary emphasis of the study is on the assessment of the environmental benefit to be gained by using cogeneration plants as a factor of enhancing the investment appeal of the district heating systems. The findings suggest that the transition of district heating systems to the next generation is impossible without changing the institutional environment, strengthening the role of active consumers, and introducing intelligent control for district heating systems.

PSXIV-14 Evaluation of Short-Chain Fatty Acids in Cattle Treated with the Natural Additive Fator P

Abstract The use of additives in the diet of ruminants consists of a management protocol that makes the livestock system more productive, sustainable and profitable. In practice, additives promote the balance of the microbial population, and improve the energy balance from food. The use of these compounds becomes advantageous as they reduce energy losses by methanogenic metabolic pathways, and the emission of enteric gases from ruminal fermentation. The short-chain fatty acids which are compounds resulting from rumen fermentation, constitute the main source of energy in the rumen, and therefore, the entire metabolic process can directly reflect the productivity performance of the cattle. Fator P is a natural additive composed of amino acids, minerals, probiotics, prebiotics and fatty acids, which was developed to meet current market needs. The aim of this study was to evaluate the synthesis of short-chain fatty acids from ruminal fluid collected from grazing animals treated with the Fator P additive over a period of 365 consecutive days. The ruminal metabolism work was conducted at Research Center of Premix (Patrocínio Paulista-SP, Brazil), using 3 cattle per treatment, which received a daily dose of 6 g of Fator P additive in the treated group, and 6 g of placebo in the control group. Ruminal fluid samples were collected weekly, and the analysis of short-chain fatty acids were carried out by the method of gas chromatography coupled to mass spectrometry. The results of the difference between means showed an increase of 15.2% (P < 0.0001) in the production of total fatty acids in the group treated with the natural additive Fator P compared with the control group. Notably, there was also an increase in the production of the three main AGCC: 13.3% for acetate (P < 0.0001); 14.7% for propionate (P = 0.0003); and 18.4% for butyrate (P = 0.0001; Table 1). Statistical analyzes were performed using the ANOVA test followed by the Tukey mean test (P < 0.05) in GraphPad PRISM Program 7.00 version. Therefore, the results indicate that the natural additive Fator P improves energy levels through the increase of short-chain fatty acids and directly reflects on the productivity indexes of the cattle. Furthermore, the product reduces the use of growth promoting antibiotics, improve intestine health, immune response of animals, carcass finishing, increase herd weight gain and milk production in a profitable and sustainable way for the cattle breeder.