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Records with Subject: Environment
Showing records 1548 to 1572 of 3421. [First] Page: 1 59 60 61 62 63 64 65 66 67 Last
Effects of Pro-Ecological Investments on an Example of the Heating Industry—Case Study
Marcin Olkiewicz, Anna Olkiewicz, Radosław Wolniak, Adam Wyszomirski.
March 9, 2023 (v1)
Subject: Environment
Keywords: emission reduction, heating industry, heating plant, pro-ecological investment, pro-ecological technology.
This paper presents problems connected with the effects of pro-ecological investment on the example of the heating industry. The aim of the publication, resulting from the identified gap, is to analyze pro-ecological investments on the example of a Polish heating company—Miejska Energetyka Cieplna Ltd. in Koszalin. In particular, the pro-environmental activities in which the examined company engaged over the period 2017−2020 were analyzed. On the basis of existing models in the literature, the authors’ cause−effect model for analyzing pro-ecological investments was proposed and investments were realized by the analyzed organization using this model. Combining the presented causes and effects of ecological investments, it is possible to propose a cause−effect model of pro-ecological investments undertaken in organizations consisting of three causes and five effects. All causes that cause organizations to realize pro-ecological investments can be divided into three groups: low requiremen... [more]
A Time-Dependent Model for Predicting Thermal Environment of Mono-Slope Solar Greenhouses in Cold Regions
Shuyao Dong, Md Shamim Ahamed, Chengwei Ma, Huiqing Guo.
March 9, 2023 (v1)
Subject: Environment
Keywords: Chinese solar greenhouse, cold regions, heating requirement, north wall, thermal model.
Most greenhouses in the Canadian Prairies shut down during the coldest months (November to February) because of the hefty heating cost. Chinese mono-slope solar greenhouses do not primarily rely on supplemental heating; instead, they mostly rely on solar energy to maintain the required indoor temperature in winter. This study focuses on improving an existing thermal model, entitled RGWSRHJ, for Chinese-style solar greenhouses (CSGs) to increase the robustness of the model for simulating the thermal environment of the CSGs located outside of China. The modified model, entitled SOGREEN, was validated using the field data collected from a CSG in Manitoba, Canada. The results indicate that the average prediction error for indoor and relative humidity is 1.9 °C and 7.0%, and the rRMSE value is 3.3% and 11.5%, respectively. The average error for predicting the north wall and ground surface temperature is 4.2 °C and 2.3 °C, respectively. The study also conducted a case study to analyze the th... [more]
The Ukrainian Economy Transformation into the Circular Based on Fuzzy-Logic Cluster Analysis
Myroslava Bublyk, Agnieszka Kowalska-Styczeń, Vasyl Lytvyn, Victoria Vysotska.
March 9, 2023 (v1)
Subject: Environment
Keywords: circular economy, economic activity sectors, emission, fuzzy-logic cluster analysis, national economy transformation, sustainable development.
In the era of limited resources and progressive environmental degradation, the circular economy is a practical application of sustainable development. It is an alternative, but also competitive way to achieve economic growth in accordance with the principles of sustainable development. This issue was considered in this paper in the context of the Ukrainian economy. The Ukrainian economy’s transformation into a circular one needs to find ways to choose practical tools for such a transition, considering the destructive impact of economic activities on the environment, population, and economy. The goal was to develop a method of choosing tools for the circular transformations of economic activities for each cluster and to reduce man-made damage to the environment. Cluster analysis, fuzzy C-means method, and grouping of economic activities were used. Two analyzed sectors turned out to be the most interesting: mining and quarrying, and electricity, gas, steam, and air conditioning supply, w... [more]
On the Road to a Green Economy: How Do European Union Countries ‘Do Their Homework’?
Armand Kasztelan.
March 9, 2023 (v1)
Subject: Environment
Keywords: comparative analysis, EU countries, green economy, indicators, ranking, sustainable development, synthetic index, taxonomic methods, zero unitarisation method.
Multidimensional crisis phenomena (financial−economic, environmental and social), plaguing the international community, especially in the last 30 years, have intensified resentment towards traditional models of growth and socio-economic development. The European Commission has placed the idea of a green economy (GE) at the heart of the Europe 2020 strategy. This paper presents an assessment of the implementation of the green economy assumptions in EU countries in 2018, taking 2010 as the base year. Using taxonomic methods, a synthetic evaluation index (GEI—Green Economy Index) was constructed based on a multi-criterion set of 27 indicators. This paper attempts to answer the following questions: How green are the European economies? What are the main challenges in this context? The average value of the index for the EU countries decreased in the studied years from 0.3423 to 0.3294, which can be interpreted as a slowdown in the greening processes. The key recommendations for the upcoming... [more]
Analysis of Spatial Distribution of Sediment Pollutants Accumulated in the Vicinity of a Small Hydropower Plant
Paweł Tomczyk, Bernard Gałka, Mirosław Wiatkowski, Bogna Buta, Łukasz Gruss.
March 9, 2023 (v1)
Subject: Environment
Keywords: dams, environmental impacts, heavy metals, hydropower plants, renewable energy sources, rivers, sediment, sustainable development, water management.
Hydropower plants affect the distribution and composition of sediments. The main aim of this study was to analyze the spatial distribution of sediment pollution in the vicinity of a small hydropower plant. The grain composition of the sediments, the content of heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd) and select physicochemical properties (pH, electrolytic conductivity) were tested at 14 points upstream and downstream of the hydropower plant on the Ślęza River in Poland, as well as at reference point. The interactions between the tested parameters were also verified. The results of the conducted analysis show that hydropower plants significantly affect the composition and properties of sediments. Large amounts of sediment are deposited on damming weirs, accumulating heavy metals and other substances. The differences in the concentrations of elements were significant, and Cu, Ni, Cr, Zn and Pb were 8.74, 9.53, 3.63, 8.26 and 6.33 times higher, respectively, than the median value at poin... [more]
Forecasting and Assessment of the Energy Security Risk in Fuzzy Environment
Paweł Ziemba, Aneta Becker, Jarosław Becker.
March 9, 2023 (v1)
Subject: Environment
Keywords: energy management, energy security, forecasting, fuzzy set, Holt’s method, international energy security risk index, multi-criteria decision analysis, Renewable and Sustainable Energy, time trends, uncertainty analysis.
Energy security is of key importance for states and international organizations. An important issue in energy security is the assessment of current and future energy security methods. While the assessment of the current methods is relatively easy, since it is based on recent information, the assessment of the future methods is burdened with uncertainty and is therefore much more difficult. Therefore, the aim of the article is to develop a new approach for assessing current and future energy security issues based on a complex security index, supported by the computationally transparent fuzzy multi-criteria decision analysis (MCDA) method. The use of the fuzzy MCDA methods allows one to capture the uncertainty of assessments and forecasts, and the forecasts themselves were based on the Holt’s method; the international energy security risk index (IESRI) was used as the source of the data to generate the forecasts. The research compared two data sources for forecasts (IESRI categories and... [more]
Liquid Hydrogen: A Review on Liquefaction, Storage, Transportation, and Safety
Muhammad Aziz.
March 9, 2023 (v1)
Subject: Environment
Keywords: liquefaction, liquid hydrogen, ortho- to para-hydrogen, safety, storage, transportation.
Decarbonization plays an important role in future energy systems for reducing greenhouse gas emissions and establishing a zero-carbon society. Hydrogen is believed to be a promising secondary energy source (energy carrier) that can be converted, stored, and utilized efficiently, leading to a broad range of possibilities for future applications. Moreover, hydrogen and electricity are mutually converted, creating high energy security and broad economic opportunities toward high energy resilience. Hydrogen can be stored in various forms, including compressed gas, liquid hydrogen, hydrides, adsorbed hydrogen, and reformed fuels. Among these, liquid hydrogen has advantages, including high gravimetric and volumetric hydrogen densities and hydrogen purity. However, liquid hydrogen is garnering increasing attention owing to the demand for long storage periods, long transportation distances, and economic performance. This paper reviews the characteristics of liquid hydrogen, liquefaction techno... [more]
Environmental and Economic Optimization and Sizing of a Micro-Grid with Battery Storage for an Industrial Application
Fethi Khlifi, Habib Cherif, Jamel Belhadj.
March 9, 2023 (v1)
Subject: Environment
Keywords: micro-grid, objective functions, Optimization, PV/wind source, Renewable and Sustainable Energy.
This study focuses on the sizing and optimization of a micro-grid with storage, which is destined to supply the load of an economic activity zone (EAZ) in Sidi Bouzid, Tunisia. To solve this problem, a genetic algorithm is established and programmed into MATLAB. The objective functions are considered by providing three minimums, namely Greenhouse Gas emissions (GHG), Life Cycle Cost (LCC) and Embodied Energy (EE), for three values of loss of power supply probability (LPSP) previously fixed. The sizing and optimization results are found and evaluated using a time series exchange of energy during a year to determine the optimal component size of a photovoltaic/wind/battery system (PV/WT/Bat). The simulation results show that the lowest ratio of LPSP values corresponds to the higher GHG, EE, LCC, photovoltaic panels area (APV), battery storage capacity (Cn), wind turbines area (AWT) and vice versa. This means that demanding higher energy reliability leads to higher energy cost and polluti... [more]
Environmental and Cost Impacts of Food Waste in University Canteen from a Life Cycle Perspective
Jing Li, Wei Li, Lei Wang, Baihui Jin.
March 9, 2023 (v1)
Subject: Environment
Keywords: food waste, life cycle assessment (LCA), life cycle costing (LCC), university canteen, weight method.
Food waste has caused double waste of resources in the food itself and the food supply chain of production, transportation, cooking, and processing, resulting in unnecessary greenhouse gas emissions and economic losses. This paper first conducted the quantification of students’ food waste and the collection of canteens operation data in the three canteens at Taiyuan University of Technology (China) in 2019 through the weighing method and interview. Then an integration of Life Cycle Assessment and Life Cycle Costing was used to quantify the impact of food waste in university canteens on the environment and costs. The study found that the total amount of food waste in the university canteens with 22,000 students was 246.75 t/a, the carbon footprint caused by food waste was 539.28 t CO2-eq, and the cost was 4,729,900 yuan. Most of the impact of canteen meals on the environment comes from the use of energy in food cooking and the consumption of animal food types. The innovative integration... [more]
The Effect of Energy Consumption and Economic Growth on Environmental Sustainability in the GCC Countries: Does Financial Development Matter?
Hala Baydoun, Mehmet Aga.
March 9, 2023 (v1)
Subject: Environment
Keywords: CO2 emissions, economic growth, energy consumption, environmental sustainability, financial development, globalization.
Achieving environmental sustainability whilst minimizing the climate change effect has become a global endeavor. Hence, this study examined the effect of energy consumption, economic growth, financial development, and globalization on CO2 emissions in the Gulf Cooperation Council (GCC) countries. The research utilized a dataset stretching from 1995 to 2018. In a bid to investigate these associations, the study applied cross-sectional dependence (CSD), slope heterogeneity (SH), Pesaran unit root, Westerlund cointegration, cross-sectionally augmented autoregressive distributed lag (CS-ARDL), and Dumitrescu and Hurlin (DH) causality approaches. The outcomes of the CSD and SH tests indicated that using the first-generation techniques produces misleading results. The panel unit root analysis unveiled that the series are I (1). Furthermore, the outcomes of the cointegration test revealed a long-run association between CO2 emissions and the regressors, suggesting evidence of cointegration. Th... [more]
Towards Net Zero Carbon Economy: Improving the Sustainability of Existing Industrial Infrastructures in the UK
Ali Shubbar, Mohammed Nasr, Mayadah Falah, Zainab Al-Khafaji.
March 9, 2023 (v1)
Subject: Environment
Keywords: carbon neutrality, carbon offsetting, clean energy, CO2 emissions, insulation.
To comply with the new net zero greenhouse gas emissions (GHGs) target set by the United Kingdom government by 2050, different sectors including the industrial sector are required to take action to achieve this target. Improving the building envelope and production of clean energy on site are among the activities that should be considered by businesses to reduce their carbon emissions. This research analysis the current energy performance and carbon dioxide (CO2) emissions of an industrial building in Liverpool, UK utilizing the Integrated Environmental Solutions Virtual Environment (IESVE) software modeling. Then it has proposed some methods for improving the current performance and reduce the carbon footprint of the building. The results indicated that the installation of wall and floor insulation could decrease the energy usage and CO2 emissions of the building by about 56.39%. Additionally, the production of clean energy on site using solar photovoltaic (PV) panels could reduce the... [more]
Perspectives and Problems of Using Renewable Energy Sources and Implementation of Local “Green” Initiatives: A Regional Assessment
Saulius Baskutis, Jolanta Baskutiene, Valentinas Navickas, Yuriy Bilan, Wojciech Cieśliński.
March 9, 2023 (v1)
Subject: Environment
Keywords: Energy Efficiency, greenhouse gas emissions, Renewable and Sustainable Energy.
Environmental pollution, energy supply and security of supply have become major issues across the world due to climate change, limited energy sources, energy price volatility and energy supply constraints. Energy availability, energy efficiency and the replacement of fossil fuels by renewable energy sources are key factors in the global development of sustainable energy. In many countries with limited fossil fuel resources, the sustainable development of renewable energy sources is an important tool in reducing dependence on imported fuels. Some alternative energy sources, such as wind, solar, tidal and hydropower, seem almost inexhaustible. With the exception of tidal energy, all of these sources have been used extensively and for a long time. This article examines the improvement of energy security and the government’s actions to promote the use of renewable energy sources, focusing on increasing energy efficiency and reducing energy intensity and dependence on energy imports in Lith... [more]
Management of Lignocellulosic Waste towards Energy Recovery by Pyrolysis in the Framework of Circular Economy Strategy
Anna Poskart, Magdalena Skrzyniarz, Marcin Sajdak, Monika Zajemska, Andrzej Skibiński.
March 9, 2023 (v1)
Subject: Environment
Keywords: Biomass, circular economy, energy recovery, pyrolysis, waste management.
The article presents the possibilities of effective management of lignocellulosic waste by including it in the circular economy. The pyrolysis process was chosen as the thermal conversion method. This approach, due to a high flexibility of the obtained products, better quality of the solid residue (char), and the lower emission of pollutants into the atmosphere, e.g., SO2 and NOx, is a competitive solution compared to combustion process. Wood waste from alder and pine were analyzed. As part of laboratory tests, the elementary composition was determined, i.e., C, H, N, S, and O. The pyrolysis process was carried out at a temperature of 600 °C on an experimental stand for the conversion of solid fuels in a stationary bed. For the obtained data, using the Ansys Chemkin-Pro calculation tool, the detailed chemical composition of gaseous products of the pyrolysis process was modeled for a varying temperature range and residence time in the reactor. The studies have shown that for certain pro... [more]
Economic Analysis of Hydrogen Household Energy Systems Including Incentives on Energy Communities and Externalities: A Case Study in Italy
Niccolò Caramanico, Giuseppe Di Florio, Maria Camilla Baratto, Viviana Cigolotti, Riccardo Basosi, Elena Busi.
March 9, 2023 (v1)
Subject: Environment
Keywords: energy communities, externalities, hydrogen systems, LCC, NPC, self-consumers’ groups, SOFC.
The building sector is one of the key energy consumers worldwide. Fuel cell micro-Cogeneration Heat and Power systems for residential and small commercial applications are proposed as one of the most promising innovations contributing to the transition towards a sustainable energy infrastructure. For the application and the diffusion of these systems, in addition to their environmental performance, it is necessary, however, to evaluate their economic feasibility. In this paper a life cycle assessment of a fuel cell/photovoltaic hybrid micro-cogeneration heat and power system for a residential building is integrated with a detailed economic analysis. Financial indicators (net present cost and payback time are used for studying two different investments: reversible-Solid Oxide Fuel Cell and natural gas SOFC in comparison to a base scenario, using a homeowner perspective approach. Moreover, two alternative incentives scenarios are analysed and applied: net metering and self-consumers’ gro... [more]
The Nexus of World Electricity and Global Sustainable Development
Veronika Wittmann, Elif Arici, Dieter Meissner.
March 9, 2023 (v1)
Subject: Environment
Keywords: climate change, electricity grid, Energy, Hydrogen, renewables, Sustainable Development Goals.
The main part of mankind’s ecological footprint is the carbon footprint, a measure of the environmental impact of humanity’s energy release from fossil fuels. The use of fossil fuels will have to change in the forthcoming decades to a largely climate-neutral use of solar energy enabled by dramatic cost reductions for PV and wind energy systems. The impact of this trend on world society has been discussed in a previous paper. In connection with these important technical developments, the role of electricity, its transport and storage will alter in the coming decades, allowing the design and use of larger and larger electricity grids and a parallel use of hydrogen for both storage and energy transport. This will further change the energy landscape of the world. All these developments and their relationship to global sustainable development are elaborated in this cross-disciplinary paper by specifically analyzing whether the Sustainable Development Goals by the United Nations are an effec... [more]
The Effect of Environmental Degradation, Climate Change, and the European Green Deal Tools on Life Satisfaction
Manuela Ortega-Gil, Georgina Cortés-Sierra, Chaima ElHichou-Ahmed.
March 9, 2023 (v1)
Subject: Environment
Keywords: circular economy, climate change, energy and environmental taxes, environment, European Green Deal, investment on environmental protection, satisfaction life.
Environmental issues, sustainability, and climate change have become the targets of many policies from international and governmental organizations including the EU’s European Green Deal action plan. This plan provides tools to address them—which include support for the circular economy, implementation of energy and environmental taxes, and investment in environmental protection—with the aim of favoring the well-being of EU citizens. In this context, this study analyses the impact of several parameters (environmental matters, global warming, circular economy, energy and environmental taxes, and expenditure and investment on the environment) on life satisfaction, or subjective well-being, and their effects on 33 European countries. For this purpose, four econometric models were carried out using data collected from the World Values Survey (WVS), the European Values Study (EVS), and the World Bank and Eurostat, reflecting subjective citizen satisfaction data. The findings present a highl... [more]
Effect of Traffic Calming in a Downtown District of Szczecin, Poland
Alicja Sołowczuk.
March 9, 2023 (v1)
Subject: Environment
Keywords: calming of traffic, choker, raised pedestrian crossing, speed reduction, speed tables, Tempo-30 zone, traffic calming measures.
The increasing use of road vehicles has caused a number of transport and environmental issues throughout the world. To cope with them, traffic calming schemes are being increasingly implemented in built-up areas. An example of such schemes are Tempo-30 zones. The traffic calming measures applied as part of this scheme must be carefully planned in terms of location and design details in order to obtain the desired reduction in speed, traffic volume and exhaust emissions and, last but foremost, to increase the safety and facilitate the movement of vulnerable road users. The coexistence and combined effect of these measures and their design details must also be taken into account. The purpose of this study was to investigate whether the applied traffic calming measures had a considerable bearing on the reduction in speed to the desired level, as assumed in the traffic calming plan. Three street sections starting and ending with different intersection types were chosen to examine the syner... [more]
Explanations for Wind Turbine Installations: Local and Global Environmental Concerns in the Central Corridor of the United States?
John C. Pierce, Rachel M. Krause, Sarah L. Hofmeyer, Bonnie J. Johnson.
March 9, 2023 (v1)
Subject: Environment
Keywords: globalist, localist worldview, social capital, turbine installation, wind power.
Even where physical conditions appear perfectly suited for wind power production, there is significant variation in the number of turbines installed. This pattern suggests that physical conditions are a pre-requisite for, but not a determinant of, that production. This study reports the results of an analysis of the county-level correlates of wind power installations in the north−south corridor of the central United States, which contains much of the country’s greatest land-based wind resources. This study focuses on the relative effects of social capital, global climate change concern, and local biodiversity, while controlling for other potential explanations that previous research has identified as leading to support for or to opposition to turbine installation. We find (1) that greater local biodiversity is associated with fewer turbine installations; (2) that the percent of the public who believe humans are causing climate change is not associated with the number of installed turbi... [more]
Analysis of Spatial Effects in the Relationship between CO2 Emissions and Renewable Energy Consumption in the Context of Economic Growth
Mateusz Jankiewicz, Elżbieta Szulc.
March 9, 2023 (v1)
Subject: Environment
Keywords: economic growth, environmental Kuznets curve, Renewable and Sustainable Energy, spatial spillovers, spatio-temporal Durbin model.
The paper presents a spatial approach to the analysis of the relationship between air pollution, economic growth, and renewable energy consumption. The economic growth of every country is based on the energy consumption that leads to an increase in national productivity. Using renewable energy is very important for the environmental protection and security of the earth’s resources. Promoting environmentally friendly operations increases awareness of sustainable development, which is currently a major concern of state governments. In this study, we explored the influence of economic growth and the share of renewable energy out of total energy consumption on CO2 emissions. The study was based on the classical environmental Kuznets curve (EKC) and enriched with the spatial dependencies. In particular, we determined the spatial spillovers in the form of the indirect effects of changes in renewable energy consumption of a specific country on the CO2 emissions of neighboring countries. A nei... [more]
Does Crowdsourcing as Part of User-Driven Innovation Activity Affect Its Results? An Empirical Analysis of R&D Departments in Poland
Katarzyna Szopik-Depczyńska, Izabela Dembińska, Agnieszka Barczak, Angelika Kędzierska-Szczepaniak, Krzysztof Szczepaniak, Radosław Depczyński, Giuseppe Ioppolo.
March 9, 2023 (v1)
Subject: Environment
Keywords: crowdsourcing, innovation, management, social media, user-driven innovation.
Entrepreneurs have long been convinced about the power and possibilities of the Internet. Nowadays, the Internet is an integral tool for the functioning of a company, not only as an alternative distribution channel, but also as a channel of information and communication flow, a means of interaction with the environment. The increasing use of the Internet, and especially of social media, made it possible to escalate the activity of various social groups in various areas of the company’s activity, including innovation, leading to the development of crowdsourcing. Crowdsourcing has redefined the existing production rules and ways of using labor resources. Its potential lies in openness, partnership, resource sharing and global action. There are already many studies on crowdsourcing and innovation, but little attention is paid to the relationship between crowdsourcing and the determinants of innovation activity. Thus, the aim of this research is examining whether the use of crowdsourcing w... [more]
Optimal Placement and Operation of Chlorine Booster Stations: A Multi-Level Optimization Approach
Joseph D. Pineda Sandoval, Bruno Melo Brentan, Gustavo Meirelles Lima, Daniel Hernández Cervantes, Daniel A. García Cervantes, Helena M. Ramos, Xitlali Delgado Galván, José de Jesús Mora Rodríguez.
March 9, 2023 (v1)
Subject: Environment
Keywords: EPANET, genetic algorithms, Particle Swarm Optimization, social and environmental impacts, water distribution systems, water quality.
Chlorine demand as a disinfectant for water utility impacts on unintended energy consumption from electrolysis manufacture; thus, diminishing the chlorine consumption also reduces the environmental impact and energy consumption. Problems of disinfectant distribution and uniformity in Water Distribution Networks (WDN) are associated with the exponential urban growth and the physical and biochemical difficulties within the network. This study optimizes Chlorine Booster Stations (CBS) location on a network with two main objectives; (1) to deliver minimal Free Residual Chlorine (FRC) throughout all demand nodes according to country regulations, and (2) to reduce day chlorine mass concentration supplied in the system by applying an hour time pattern in CBS, consequently associated economic, energy and environmental impacts complying with regulatory standards. The application is demonstrated on a real-world WDN modeled from Guanajuato, Mexico. The resulting optimal location and disinfectant... [more]
Dynamic Influence of Wheel Flat on Fatigue Life of the Traction Motor Bearing in Vibration Environment of a Locomotive
Bingbin Guo, Zhixiang Luo, Bo Zhang, Yuqing Liu, Zaigang Chen.
March 9, 2023 (v1)
Subject: Environment
Keywords: fatigue life, gear dynamics, rolling bearing, wheel–rail contact.
Wheel flat can cause a large impact between the wheel and rail and excites a forced vibration in the locomotive and track structure systems. The working conditions and fatigue life of the motor bearings are significantly affected by the intensified wheel−rail interaction via the transmission path of the gear mesh. In this study, a fatigue life prediction method of the traction motor bearings in a locomotive is proposed. Based on the L−P theory or ISO 281 combined with the Miner linear damage theory and vehicle−track coupled dynamics, the irregular loads induced by the track random irregularity and gear mesh are considered in this proposed method. It can greatly increase the accuracy of predictions compared with the traditional prediction models of a rolling bearing life whose bearing loads are assumed to be constant. The results indicate that the periodic impact forces and larger mesh forces caused by the wheel flat will reduce the fatigue life of the motor bearings, especially when th... [more]
Precise Measurements of the Temperature Influence on the Complex Permittivity of Power Transformers Moistened Paper-Oil Insulation
Pawel Zukowski, Przemyslaw Rogalski, Konrad Kierczynski, Tomasz N. Koltunowicz.
March 9, 2023 (v1)
Subject: Environment
Keywords: dielectric permittivity, electrotechnical pressboard, environmental pollution, failure prevention, imaginary part of permittivity, insulation condition diagnostics, mineral oil, moisture, power transformer.
The reference characteristics of complex permittivity of the transformers insulation solid component were determined for use in the precise diagnostics of the power transformers insulation state. The solid component is a composite of cellulose, insulating oil and water nanoparticles. Measurements were made in the frequency range from 10−4 Hz to 5000 Hz at temperatures from 293.15 to 333.15 K. Uncertainty of temperature measurements was less than ±0.01 K. Pressboard impregnated with insulating oil with a water content of (5.0 ± 0.2) by weight moistened in a manner maximally similar to the moistening process in power transformers was investigated. It was found that there are two stages of changes in permittivity and imaginary permittivity components, occurring for low and high frequency. As the temperature increases, the frequency dependencies of the permittivity and imaginary permittivity component shifts to the higher frequency region. This phenomenon is related to the change of relaxa... [more]
A Critical Review on Recycling Composite Waste Using Pyrolysis for Sustainable Development
Ramez Abdallah, Adel Juaidi, Mahmut A. Savaş, Hüseyin Çamur, Aiman Albatayneh, Samer Abdala, Francisco Manzano-Agugliaro.
March 9, 2023 (v1)
Subject: Environment
Keywords: carbon fiber, CFRC, GFRC, glass fiber, pyrolysis, recycling, reinforced composites, Sustainability.
The rising usage of carbon and glass fibers has raised awareness of scrap management options. Every year, tons of composite scrap containing precious carbon and glass fibers accumulate from numerous sectors. It is necessary to recycle them efficiently, without harming the environment. Pyrolysis seems to be a realistic and promising approach, not only for efficient recovery, but also for high-quality fiber production. In this paper, the essential characteristics of the pyrolysis process, their influence on fiber characteristics, and the use of recovered fibers in the creation of a new composite are highlighted. Pyrolysis, like any other recycling process, has several drawbacks, the most problematic of which is the probability of char development on the resultant fiber surface. Due to the char, the mechanical characteristics of the recovered fibers may decrease substantially. Chemically treating and post-heating the fibers both help to reduce char formation, but only to a limited degree.... [more]
Development of a Multi-Segment Parallel Compressor Model for a Boundary Layer Ingesting Fuselage Fan Stage
Jonas Voigt, Jens Friedrichs.
March 9, 2023 (v1)
Subject: Environment
Keywords: boundary layer ingestion, fan performance, parallel compressor model.
The present methodological study aims to assess boundary layer ingestion (BLI) as a promising method to improve propulsion efficiency. BLI utilizes the low momentum inflow of the wing or fuselage boundary layer for thrust generation in order to minimize the required propulsive power for a given amount of thrust for wing or fuselage-embedded engines. A multi-segment parallel compressor model (PCM) is developed to calculate the power saving from full annular BLI as occurring at a fuselage tail center-mounted aircraft engine, employing radially subdivided fan characteristics. Applying this methodology, adverse effects on the fan performance due to varying inlet distortions depending on flight operating point as well as upstream boundary layer suction can be taken into account. This marks one step onto a further segmented PCM model for general cases of BLI-induced inlet distortion and allows the evaluation of synergies between combined BLI and active laminar flow control as a drag reductio... [more]
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