bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical Investigation of Climate Change Effects on the Utilization of the Sediment Heat Energy
Authors: Girgibo Nebiyu , Mäkiranta Anne , Lü Xiaoshu , Hiltunen Erkki
Published: January 2022

Suvilahti, a suburb of the city of Vaasa in western Finland, was the first area to use seabed sediment heat as the main source of heating for a high number of houses. Moreover, in the same area, a unique land uplift effect is ongoing. The aim of this paper is to solve the challenges and find opportunities caused by global warming by utilizing seabed sediment energy as a renewable heat source. Measurement data of water and air temperature were analyzed, and correlations were established for the sediment temperature data using Statistical Analysis System (SAS) Enterprise Guide 7.1. software. The analysis and provisional forecast based on the autoregression integrated moving average (ARIMA) model revealed that air and water temperatures show incremental increases through time, and that sediment temperature has positive correlations with water temperature with a 2-month lag. Therefore, sediment heat energy is also expected to increase in the future. Factor analysis validations show that the data have a normal cluster and no particular outliers. This study concludes that sediment heat energy can be considered in prominent renewable production, transforming climate change into a useful solution, at least in summertime.
Territorial Cooperation—A Factor Stimulating Baltic Sea Region Energy Transition
Authors: Studzieniecki Tomasz , Palmowski Tadeusz , Joeck Remigiusz
Published: January 2022

Energy transition is a multi-dimensional process of developing sustainable economies by seeking renewable energy sources, saving energy, and improving energy efficiency. This process follows the rules of sustainable development. The article presents an analysis of energy transition in the Baltic Sea Region (BSR) enjoying long-term and intensive territorial cooperation. The region embraces 11 countries diversified in terms of their economic development level and the use of renewable energy sources. The article strives to answer the question of whether territorial cooperation contributes to BSR energy transition, and if so, in what way. Another goal is to identify the transition drivers that arise from the Baltic Sea Region’s unique characteristics. The authors applied the system analysis methodology. The performed literature studies allowed the researchers to identify the attributes of energy transition. Empirical research relied on secondary sources, including the European Union (EU) statistics, The International Renewable Energy Agency (IRENA), the EU Strategy for the Baltic Sea Region (EUSBSR), and related documents. The key role in the conducted research can be attributed to the EU projects database (keep.eu), which enabled identifying the 2016–2020 programmes and projects. The research identified 14 BSR territorial cooperation programmes and 1471 projects conducted under the programmes, including 137 energy transition-related projects. The project results were presented in quantitative and qualitative terms.
Current Harmonic Aggregation Cases for Contemporary Loads
Authors: Daniel Kamran , Kütt Lauri , Iqbal Muhammad Naveed , Shabbir Noman , Rehman Ateeq Ur , Shafiq Muhammad , Hamam Habib
Published: January 2022

Power electronic circuits in modern power supplies have improved the conversion efficiency on the one hand but have also increased harmonic emissions. Harmonic currents from the operation of these units affect the voltage waveforms of the network and could compromise the reliability of the network. Load and source non-linearity can, therefore, limit the renewable source’s hosting capacity in the grid, as a large number of inverter units may increase the harmonic distortions. As a result, voltage and current distortions could reach unbearable levels in devices connected to the network. Harmonic estimation modelling often relies on measurement data, and differences may appear in mathematical simulations as the harmonic aggregation or cancellation may generate different results due to the inaccuracies and limitations of the measurement device. In this paper, the effect of harmonic currents cancellation on the aggregation of different load currents is evaluated to show its impact in the network by presenting a comparison between the measurement and mathematical aggregation of harmonics. Furthermore, the harmonic cancellation phenomenon is also qualified for multiple loads connected to the power supply.
Directions and Extent of Flows Changes in Warta River Basin (Poland) in the Context of the Efficiency of Run-of-River Hydropower Plants and the Perspectives for Their Future Development
Authors: Sojka Mariusz
Published: January 2022

This paper presents changes in the flow of 14 rivers located in the Warta River basin, recorded from 1951 to 2020. The Warta is the third-longest river in Poland. Unfortunately, the Warta River catchment area is one of the most water-scarce regions. It hosts about 150 hydropower plants with a capacity of up to 5 kW. The catchment areas of the 14 smaller rivers selected for the study differ in location, size, land cover structure and geological structure. The paper is the first study of this type with respect to both the number of analyzed catchments, the length of the sampling series and the number of analyzed flow characteristics in this part of Europe. The analysis of changes in the river flows was performed with reference to low minimum, mean and maximum monthly, seasonal and annual flows. Particular attention was paid to 1, 3, 7, 30 and 90-day low flows and durations of the flows between Q50 and Q90%. In addition, the duration of flows between Q50 and Q90% were analysed. Analysis of the direction and extent of particular flow types was performed by multitemporal analysis using the Mann–Kendall (MK) and Sen (S) tests. The analysis of multiannual flow sequences from the years 1951–2020 showed that the changes varied over the time periods and catchments. The most significant changes occurred in the low flows, while the least significant changes occurred in the high flows. From the point of view of the operation of the hydropower sector, these changes may be unfavourable and result in a reduction in the efficiency of run-of-river hydropower plants. It was established that local factors play a dominant role in the shaping of river flows in both positive and negative terms, for the efficiency of the hydropower plants.
Impact of Sustainable Development and Environmental Protection on the Volume of Domestic Hard Coal Sales in Poland
Authors: Rybak Aurelia , Włodarczyk Ewelina
Published: January 2022

The paper presents the results of an analysis of the impact of activities related to the implementation of Poland’s climate policy on the level of demand for hard coal. The authors used sets of indicators built by Eurostat during the analysis. The analysis was based on a set of indicators that had not previously been used for this purpose. The applied ARAMAX model made it possible to study the impact of the presented indicators on the volume of demand for hard coal in Poland. They were introduced to the ARMAX model as explanatory variables. The demand for hard coal in Poland was the dependent variable. The set of indicators was verified, and finally only statistically significant factors were used to build the model. The forecast of the demand for hard coal was made until 2022. It showed that the volume of coal sales would systematically fall as long as factors affecting demand remain constant. However, an additional factor was taken into account in the analysis, namely the increase in demand and prices for hard coal on world markets. The ARIMA model was used to forecast price levels for the next 12 months. The forecast indicates that the time series of prices should maintain an upward trend within the examined time period. Building an accurate and reliable forecast is the basis for effective planning of coal production and is adjusted to the demand for this fuel.
Role and Important Properties of a Membrane with Its Recent Advancement in a Microbial Fuel Cell
Authors: Banerjee Aritro , Calay Rajnish Kaur , Eregno Fasil Ejigu
Published: January 2022

Microbial fuel cells (MFC) are an emerging technology for wastewater treatment that utilizes the metabolism of microorganisms to generate electricity from the organic matter present in water directly. The principle of MFC is the same as hydrogen fuel cell and has three main components (i.e., anode, cathode, and proton exchange membrane). The membrane separates the anode and cathode chambers and keeps the anaerobic and aerobic conditions in the two chambers, respectively. This review paper describes the state-of-the-art membrane materials particularly suited for MFC and discusses the recent development to obtain robust, sustainable, and cost-effective membranes. Nafion 117, Flemion, and Hyflon are the typical commercially available membranes used in MFC. Use of non-fluorinated polymeric membrane materials such as sulfonated silicon dioxide (S-SiO2) in sulfonated polystyrene ethylene butylene polystyrene (SSEBS), sulfonated polyether ether ketone (SPEEK) and graphene oxide sulfonated polyether ether ketone (GO/SPEEK) membranes showed promising output and proved to be an alternative material to Nafion 117. There are many challenges to selecting a suitable membrane for a scaled-up MFC system so that the technology become technically and economically viable.
Design and Performance Investigation of a Compact Catalytic Reactor Integrated with Heat Recuperator
Authors: Chen Qiang , Mao Mingming , Gao Min , Liu Yongqi , Shi Junrui , Li Jia
Published: January 2022

The catalytic combustion has the advantage of lower auto-ignition temperature and helps to expand the combustible limit of lean premixed gas. However, the intake needs to be preheated to certain temperature commonly through an independent heat exchanger. Similar to the principles of non-catalytic RTO combustion, this paper presents a similar approach whereby the combustion chamber is replaced by a catalytic combustion bed. A new catalytic reactor integrated with a heat recuperator is designed to enhance the heat recirculation effect. Using a two-dimensional computational fluid dynamics model, the performance of the reactor is studied. The reaction performances of the traditional and compact reactors are compared and analyzed. Under the same conditions, the compact reactor has better reaction performance and heat recirculation effect, which can effectively decrease the ignition temperature of feed gas. The influences of the inlet velocity, the inlet temperature, the methane concentration, and the thermal conductivity of porous media on the reaction performance of integrated catalytic reactor are studied. The results show that the inlet velocity, inlet temperature, methane concentration, and thermal conductivity of porous media materials have important effects on the reactor performance and heat recirculation effect, and the thermal conductivity of porous media materials has the most obvious influence. Moreover, the reaction performance of multiunit integrated catalytic reactor is studied. The results show that the regenerative effect of multiunit integrated catalytic reactor is further enhanced. This paper is of great significance to the recycling of low calorific value gas energy and relieving energy stress in the future.
The Impact of Soil Hydrothermal Properties on Geothermal Power Generation (GPG): Modeling and Analysis
Authors: Liu Zhengguang , Hou Gaoyang , Song Ying , Taherian Hessam , Qi Shuaiwei
Published: January 2022

Geothermal power plants have become the main application that utilizes geothermal energy. The utilization of deep geothermal energy adheres great importance to the soil condition. One of the biggest challenges faced by geothermal power plant designers is to reduce the risk of soil exploration. To solve this problem, forecasting by modeling has proven to be an important tool to address the problem. In this research, a geo-model was established by modeling three geological layers with different hydraulic and thermal properties to solve the above dilemma. The layers, elevation, and fault zones were simulated using interpolation functions from an artificial dataset. The coupled porous media flow and heat transfer problem using Darcy’s law, as well as heat transfer in porous media interfaces, were studied. The evolution of the flow field, hydrothermal performance, and temperature gradient were also analyzed for a period of 10 years. The results showed the recoverable thermal energy area gradually moved downwards during the 10-year simulation time. When the distance between the recharge well and the production well exceeded 200 m, the collection efficiency was significantly decreased. After 5 years of extraction, the power generation efficiency of the heat source will be less than 9.75%. These results effectively avoided the exploration cost of geothermal power plant site selection, which is significant for the efficiency improvement of geothermal energy.
Radiant Conditioning Retrofitting for Residential Buildings
Authors: Do Hung Q. , Luther Mark B. , Amirkhani Mehdi , Wang Zheng , Martek Igor
Published: January 2022

In order to achieve Australia’s greenhouse gas emissions reduction targets, a majority of the existing residential building stock in Australia will require retrofitting in favour of energy-efficient solutions. This paper considers retrofitting for conditioning to be one of the most straightforward and offers the greatest potential to deliver significant comfort and energy-saving results. Radiant conditioning systems are not new, yet some game-changing innovations have taken place over the last decade that may require an entire paradigm shift in the manner we condition our buildings. The reiteration of the principle ‘thermally active systems’ suggests that our buildings need to accommodate these systems into the fabric of building components. However, extremely few products and/or innovative solutions for doing such seem to be provided by the industry. We seem incompetent with solutions that are not costing the Earth, insulating, lightweight, and offering an instant response time to conditioning. We still have the concept embedded in our minds that radiative systems consist of heavy ‘combat’ construction with time lags of a day or two and that they are very costly to implement, especially if we are to retrofit a project. The purpose of this paper is to rectify and change our understanding of radiant systems, namely through a review of the existing technology and its recent advancements. It intends to introduce the fact that radiant systems can become highly reactive, responsive, and thermally dynamic conditioning systems. Lightweight radiant systems can be 40% more energy-efficient than common air conditioners and can respond in less than 15 min rather than in the hours required of heavy radiant systems. Thus, an insulated, lightweight radiant system is ideal for retrofitting residential buildings. Furthermore, this paper supports and introduces various systems suited to retrofitting a residential building with hydronic radiant systems.
Development of Broadband Resistive–Capacitive Parallel–Connection Voltage Divider for Transient Voltage Monitoring
Authors: Xie Shijun , Mu Zhou , Ding Weidong , Wan Zhenbo , Su Shaochun , Zhang Chenmeng , Zhang Yu , Xia Yalong , Luo Donghui
Published: January 2022

The on-site measurement of transient voltages is of great significance in analyzing the fault cause of power systems and optimizing the insulation coordination of power equipment. Conventional voltage transformers normally have a narrow bandwidth and are unable to accurately measure various transient voltages in power systems. In this paper, a wideband parallel resistive–capacitive voltage divider is developed, which can be used for online monitoring of transient voltages in a 220 kV power grid. The structures of the high-voltage and low-voltage arms were designed. The internal electric field distribution of the high-voltage arm was analyzed. The influence factors and improvement techniques of the upper frequency limit were studied. The parameters of the elements of the divider were determined. The voltage withstand performances and scale factors under lightning impulses and AC and DC voltages, the temperature stabilities of scale factors and the step response and bandwidth of the developed voltage divider were tested. The results show that the deviations of the scale factors under various voltage waveforms and different temperatures ranging from −20 to 40 °C are within 3%. The withstand voltage meets the relevant requirements specified in IEC60071-1-2011. The step response 10~90% rise time is approximately 29 ns, and the 3 dB bandwidth covers the range of DC to 10 MHz.
Edge-Oriented Computing: A Survey on Research and Use Cases
Authors: Sulieman Nour Alhuda , Ricciardi Celsi Lorenzo , Li Wei , Zomaya Albert , Villari Massimo
Published: January 2022

Edge computing is a distributed computing paradigm such that client data are processed at the periphery of the network, as close as possible to the originating source. Since the 21st century has come to be known as the century of data due to the rapid increase in the quantity of exchanged data worldwide (especially in smart city applications such as autonomous vehicles), collecting and processing such data from sensors and Internet of Things devices operating in real time from remote locations and inhospitable operating environments almost anywhere in the world is a relevant emerging need. Indeed, edge computing is reshaping information technology and business computing. In this respect, the paper is aimed at providing a comprehensive overview of what edge computing is as well as the most relevant edge use cases, tradeoffs, and implementation considerations. In particular, this review article is focused on highlighting (i) the most recent trends relative to edge computing emerging in the research field and (ii) the main businesses that are taking operations at the edge as well as the most used edge computing platforms (both proprietary and open source). First, the paper summarizes the concept of edge computing and compares it with cloud computing. After that, we discuss the challenges of optimal server placement, data security in edge networks, hybrid edge-cloud computing, simulation platforms for edge computing, and state-of-the-art improved edge networks. Finally, we explain the edge computing applications to 5G/6G networks and industrial internet of things. Several studies review a set of attractive edge features, system architectures, and edge application platforms that impact different industry sectors. The experimental results achieved in the cited works are reported in order to prove how edge computing improves the efficiency of Internet of Things networks. On the other hand, the work highlights possible vulnerabilities and open issues emerging in the context of edge computing architectures, thus proposing future directions to be investigated.
Diagnosis for Slight Bearing Fault in Induction Motor Based on Combination of Selective Features and Machine Learning
Authors: Nakamura Hisahide , Mizuno Yukio
Published: January 2022

Induction motors are widely used in industry and are essential to industrial processes. The faults in motors lead to high repair costs and cause financial losses resulting from unexpected downtime. Early detection of faults in induction motors has become necessary and critical in reducing costs. Most motor faults are caused by bearing failure. Machine learning-based diagnostic methods are proposed in this study. These methods use effective features. First, load currents of healthy and faulty motors are measured while the rotating speed is changing continuously. Second, experiments revealed the relationship between the magnitude of the amplitude of specific signals and the rotating speed, and the rotating speed is treated as a new feature. Third, machine learning-based diagnoses are conducted. Finally, the effectiveness of machine learning-based diagnostic methods is verified using experimental data.
Which Stakeholders’ Sector Matters in Rural Development? That Is the Problem
Authors: Kusio Tomasz , Fiore Mariantonietta
Published: January 2022

In the age of COVID, the regaining of economies appears mostly imperative, and rural areas could play a crucial role in this framework. The question of inhabitants’ dispersion and low density, and the exodus of rural people to bigger urban centers have determined an adverse effect on rural development. Rural isolation rises to be a higher order good, delivering a higher degree of security in the pandemic context for those seeking refuge from gatherings of cities. Rural areas provide food, natural environments, and resources that help occupations, development, and wealth trends and preserve cultural heritage. Consequently, rural spaces are vital for several motives and thus it is essential to focus on issue of rural development, especially since lacking rural development does not allow dialoging about development in a regional and/or national perspective. This paper investigates the stakeholders’ impact on rural development, by considering the increasing role of stakeholders as well as the specificity of the diverse objectives pursued by these groups. As there are several stakeholder groups, attention was sweeping, defining them in a sectoral way to corporate, sciences, public administrations, and society. Where there was a need to distinguish among these sectors groups of stakeholders in a more detailed way, such identification took place, for example, in relation to social leaders. The analysis of the results of the questionnaire survey performed in 2020 aimed to accomplish the identified purposes of the paper. The online survey using the CAWI method was conducted in southeastern Poland among people representing all stakeholder groups. The outcomes of the investigation indicate the great prominence of business in the development of rural areas being able to generate added value and influence the increase of entity potential.
Overview of Propulsion Systems for Unmanned Aerial Vehicles
Authors: Zhang Bowen , Song Zaixin , Zhao Fei , Liu Chunhua
Published: January 2022

Unmanned Aerial Vehicle (UAV) propulsion technology is significantly related to the flight performance of UAVs, which has become one of the most important development directions of aviation. It should be noted that UAVs have three types of propulsion systems, namely the fuel, hybrid fuel-electric, and pure electric, respectively. This paper presents and discusses the classification, working principles, characteristics, and critical technologies of these three types of propulsion systems. It is helpful to establish the development framework of the UAV propulsion system and provide the essential information on electric propulsion UAVs. Additionally, future technologies and development, including the high-power density motors, converters, power supplies, are discussed for the electric propulsion UAVs. In the near future, the electric propulsion system would be widely used in UAVs. The high-power density system would become the development trend of electric UAVs. Thus, this review article provides comprehensive views and multiple comparisons of propulsion systems for UAVs.
A Convenient Method for the Accurate Calculation of Fin Efficiency of H-Type Fins Based on Linear Nomograms and Fitting Formulae
Authors: Feng Yongshi , Wu Xin , Liang Cai , Sun Zhongping
Published: January 2022

Fin efficiency, as a measure of the effectiveness of the heat transfer enhancement, is of great importance in studying the heat transfer performance of H-type finned tube banks. The fin efficiency of square fins is adopted by most researchers as an alternative to that of H-type fins, which can create certain errors in the fin efficiency of H-type fins. For this paper, the linear nomograms and fitting formulae of fin efficiency of H-type fins are obtained by the definition method of fin efficiency based on numerous numerical simulations, and the results calculated by this method are verified by experimental data. On this basis, the effects of three geometric parameters (slit width, fin height, and fin thickness) and two thermal parameters (surface heat transfer coefficient and fin thermal conductivity) on the fin efficiency of H-type fins are also investigated and compared to those of square fins. The results indicate that the fin efficiency of H-type fins increases with the increment of fin thickness and thermal conductivity, and decreases with the increase of slit width, fin height, and surface heat transfer coefficient. Accordingly, the linear nomograms and fitting formulae for the fin efficiency of H-type fins, which are well compatible with experimental data, can help to facilitate further theoretical research and engineering application.
Flowing Refractometer for Feed Water State Control in the Second Loop of Nuclear Reactor
Authors: Davydov Vadim , Gureeva Irena , Davydov Roman , Dudkin Valentin
Published: January 2022

The necessity to control the feed water state in the second loop of a nuclear power plant nuclear reactor is justified. The different methods of the state control of flowing water in the pipeline are reviewed. It has been established that controlling the feed water state should not result in irreversible changes in its chemical composition and physical structure. A change in the composition or structure of feed water leads to a change in its heat capacity. The heat transfer deteriorates, the production of electrical energy in the installation decreases, and the additional release of heat into the atmosphere increases. This process also occurs during the heat capacity changes for other reasons. The method for controlling the feed water heat capacity by measuring the value of the refractive index n is developed. The design of a flow-through refractometer based on the total internal reflection for control of the feed water state in the stream is made. The dependence of the heat capacity change of feed water from the refractive index is established. The results of research on different types of water are presented.
Numerical and Experimental Investigation of a Non-Premixed Double Swirl Combustor
Authors: Lin Jiming , Bao Ming , Zhang Feng , Zhang Yong , Yang Jianhong
Published: January 2022

This paper focuses on a detailed numerical investigation combined with experimental research for a non-premixed swirl combustor, which aims to analyze the effects of the blade angle of the outer swirler and equivalence ratio on flow and combustion characteristics. In the experiment, the temperature in the furnace was obtained with a thermocouple, while a realizable k-ε turbulence model and two-step reaction mechanism of methane and air are used in the numerical method. The calculation results are in good agreement with the experimental data. The results reveal that the air flow rate through the swirler accounts for a small amount of the total air due to the influence of the draft fan, and there is no central recirculation zone (CRZ) despite the presence of the swirler. It was also found that NO emissions gradually decrease as the blade angle of the outer swirler increases. It was also indicated that the average temperature is 100 K higher than the general combustor with a 58° blade angle in the furnace by increasing the equivalent ratio of the tertiary air area, and the NO emissions reduced by approximately 25%. This study can provide guidance for the operation and structural design of non-premixed swirl combustors.
Corporate Risk Tolerance and Acceptability towards Sustainable Energy Transition
Authors: Rafiq Muhammad , Akbar Ahsan , Maqbool Saif , Sokolová Marcela , Haider Syed Arslan , Naz Shumaila , Danish Syed Muhammad
Published: January 2022

The omnipresence of risk prevails in almost every aspect of human life. Individuals and societal factors are pivotal in the decision-making process to judge acceptability and tolerability of risk. Tolerability of risk (ToR) is characterized by dynamism pinned in the process of decision making that helps to gauge the society and individual’s risk. The energy transition implies switching the energy system from fossil fuels or any traditional mechanism to modern renewable sources that are sustainable. The energy transition is paramount important in the current global energy system to attain sustainable goals for organizations. This study used the positivism research paradigm to address the research questions. The quantitative approach helps to examine the cause-and-effect relationship. It also helps to collect systematic information to meet the objectives of the research. A total sample of 300 was selected for the data collection from renewable energy companies. The study used positivism research philosophy applied deductive approach. The data is analyzed through PLS-SEM. It is summarized that the scale of risk acceptability and tolerability in Pakistan is moderate which encourages companies to work progressively and increases sociocultural activities to make society a partner of this new shift in energy transition that will ultimately increase the level of risk acceptability. Nevertheless, as a society, people are neither high-risk takers nor risk avoiders due to income constraints, macroeconomic uncertainty, and political instability.
A Survey of Islanding Detection Methods for Microgrids and Assessment of Non-Detection Zones in Comparison with Grid Codes
Authors: Cebollero José Antonio , Cañete David , Martín-Arroyo Susana , García-Gracia Miguel , Leite Helder
Published: January 2022

Detection of unintentional islanding is critical in microgrids in order to guarantee personal safety and avoid equipment damage. Most islanding detection techniques are based on monitoring and detecting abnormalities in magnitudes such as frequency, voltage, current and power. However, in normal operation, the utility grid has fluctuations in voltage and frequency, and grid codes establish that local generators must remain connected if deviations from the nominal values do not exceed the defined thresholds and ramps. This means that islanding detection methods could not detect islanding if there are fluctuations that do not exceed the grid code requirements, known as the non-detection zone (NDZ). A survey on the benefits of islanding detection techniques is provided, showing the advantages and disadvantages of each one. NDZs size of the most common passive islanding detection methods are calculated and obtained by simulation and compared with the limits obtained by ENTSO-E and islanding standards in the function of grid codes requirements in order to compare the effectiveness of different techniques and the suitability of each one.
eSCIFI: An Energy Saving Mechanism for WLANs Based on Machine Learning
Authors: Apostolo Guilherme Henrique , Bernardini Flavia , Magalhães Luiz C. Schara , Muchaluat-Saade Débora C.
Published: January 2022

As wireless local area networks grow in size to provide access to users, power consumption becomes an important issue. Power savings in a large-scale Wi-Fi network, with low impact to user service, is undoubtedly desired. In this work, we propose and evaluate the eSCIFI energy saving mechanism for Wireless Local Area Networks (WLANs). eSCIFI is an energy saving mechanism that uses machine learning algorithms as occupancy demand estimators. The eSCIFI mechanism is designed to cope with a broader range of WLANs, which includes Wi-Fi networks such as the Fluminense Federal University (UFF) SCIFI network. The eSCIFI can cope with WLANs that cannot acquire data in a real time manner and/or possess a limited CPU power. The eSCIFI design also includes two clustering algorithms, named cSCIFI and cSCIFI+, that help to guarantee the network’s coverage. eSCIFI uses those network clusters and machine learning predictions as input features to an energy state decision algorithm that then decides which Access Points (AP) can be switched off during the day. To evaluate eSCIFI performance, we conducted several trace-driven simulations comparing the eSCIFI mechanism using both clustering algorithms with other energy saving mechanisms found in the literature using the UFF SCIFI network traces. The results showed that eSCIFI mechanism using the cSCIFI+ clustering algorithm achieves the best performance and that it can save up to 64.32% of the UFF SCIFI network energy without affecting the user coverage.
Sustainable Value Chain of Industrial Biocomposite Consumption: Influence of COVID-19 and Consumer Behavior
Authors: Rutitis Didzis , Smoca Anete , Uvarova Inga , Brizga Janis , Atstaja Dzintra , Mavlutova Inese
Published: January 2022

The COVID-19 pandemic has been one of the most unprecedented crises of recent decades with a global effect on society and the economy. It has triggered changes in the behavior and consumption patterns of both final consumer and industrial consumers. The consumption patterns of industrial consumers are also influenced by changes in consumer values, environmental regulations, and technological developments. One of the technological highlights of the last decade is biocomposite materials being increasingly used by the packaging industry. The pandemic has highlighted the problems and challenges of the development of biocomposites to adapt to new market conditions. This study aims to investigate the industrial consumption of biocomposite materials and the influence of the COVID-19 pandemic on the main stages of the value chain of sustainable industrial consumption of biocomposites. The research results reveal there is a growing interest in the use of biocomposites. Suppliers and processors of raw materials are being encouraged to optimize and adapt cleaner production processes in the sustainable transition pathway. The study highlights the positive impact of COVID-19 on the feedstock production, raw material processing, and packaging manufacturing stages of the value chain as well as the neutral impact on the product manufacturing stage and negative impact on the retail stage. The companies willing to move toward the sustainable industrial chain have to incorporate economic, environmental, social, stakeholder, volunteer, resilience, and long-term directions within their strategies.
Review of NZEB Criteria: Design of Life Containers in Operations Area
Authors: Garzón-Juan Mario , Nieto-Morote Ana , Ruz-Vila Francisco
Published: January 2022

The Spanish Ministry of Defense is currently attempting to reduce the amount of energy that is consumed by its military bases and has therefore raised concerns about how to make their facilities more energy efficient. To fulfill this objective, the Spanish army has developed various studies and projects, as well as a technical prescription sheet that defines the thermal transmittance values of the materials that are to be used to construct the different elements of the containers that make up the temporary housing units at Spanish military camps. Both governments and private entities have developed initiatives that are aimed at improving the energy efficiency of buildings, which are classified into two groups: those aimed at the development of mandatory building codes and those that are based on voluntary certification programs. The use of passive strategies is one of the key actions that is being implemented to achieve the NZEB category, as its first requirement is to be a “very low energy consumption building”. This paper compares the energy efficiency requirements of the tents and containers that are used in military camps and the energy-efficient design requirements that are demanded by the energy efficiency standards for buildings in the civil sector. Through this comparison, we determine how energy efficient the current living spaces in military camps are in order to define strategies that can be implemented to improve the design requirements of these living spaces so to reduce the consumption and operation logistics and to improve both operability and safety in military camp facilities.
Analysis of Stand-Alone Photovoltaic—Marine Current Hybrid System and the Influence on Daily and Seasonal Energy Storage
Authors: Olmedo-González Jorge , Ramos-Sánchez Guadalupe , Garduño-Ruiz Erika Paola , González-Huerta Rosa de Guadalupe
Published: January 2022

Stand-alone systems in remote regions require the utilization of renewable resources; however, their natural intermittence requires the implementation of energy-storage systems that allow a continuous power supply. More than one renewable source is usually available at the same site. Thus, the choice of a hybrid system seems viable. It is relevant to study hybrid systems as they could reduce energy storage; however, sizing the hybrid system might have several implications, not only for the available daily energy, but also for the required daily energy storage and surplus seasonal energy. In this work, we present a case study of a stand-alone, conventional household powered by photovoltaic and marine-current-energy systems in Cozumel, Mexico. The analysis of different hybridization degrees serves as a guidance tool to decide whether hybrid systems are required for a specific situation; in contrast to previous approaches, where ideal consumption and generation profiles have been utilized, yearlong profiles were utilized here. The renewable potential data were obtained on site at an hourly resolution; requirements such as size of and cycles in the daily and seasonal energy storage were analyzed according to the degree of participation or hybridization of the proposed renewable systems through an algorithm that evaluates power generation and daily consumption throughout the year. A further analysis indicated that marine-current-energy implementation reduces the size of the daily energy-storage system by 79% in comparison to the use of only a photovoltaic system due to the similarity between the energy-demand profile and the marine-current-energy production profile. The results indicate that a greater participation of marine currents can help decrease daily storage while increasing seasonal storage by 16% compared to using only solar energy. On the other hand, hybridization enabled a reduction in the number of daily charge and discharge cycles at 0.2 hybridization degrees. It also allowed us to reduce the seasonal energy storage by 38% at 0.6 hybridization degrees with respect to only using energy from marine currents. Afterwards, energy-storage technologies were evaluated using the TOPSIS Multi-Criteria Decision Analysis to validate the best-suited technology for the energy-storage system. The evaluation considered the characteristics of the technology and the periods of energy storage. In this work, hybrid storage systems were mandatory since, for daily storage, lithium-ion batteries are better suited, while for seasonal storage, hydrogen-producing systems are more suitable to manage the amount of energy and the storage duration due to the high seasonal renewable-energy variations.
A Boussinesq-Type Model for Nonlinear Wave-Heaving Cylinder Interaction
Authors: Karambas Theofanis , Loukogeorgaki Eva
Published: January 2022

In the present work, a Boussinesq-type numerical model is developed for the simulation of nonlinear wave-heaving cylinder interaction. The wave model is able to describe the propagation of fully dispersive and weakly nonlinear waves over any finite water depth. The wave-cylinder interaction is taken into account by solving simultaneously an elliptic equation that determines the pressure exerted by the fluid on the floating body. The heave motion for the partially immersed floating cylinder under the action of waves is obtained by solving numerically the body’s equation of motion in the z direction based on Newton’s law. The developed model is applied for the case of a fixed and a free-floating circular cylinder under the action of regular waves, as well as for a free-floating cylinder undergoing a forced motion in heave. Results (heave and surge exciting forces, heave motions, and wave elevation) are compared with those obtained using a frequency domain numerical model, which is based on the boundary integral equation method.
Application of the Renewable Energy Sources at District Scale—A Case Study of the Suburban Area
Authors: Zygmunt Marcin , Gawin Dariusz
Published: January 2022

The protection of the natural environment and countering global warming are crucial worldwide issues. The residential sector has a significant impact on overall energy consumption and associated greenhouse gas emissions. Therefore, it is extremely important to focus on all of the activities that can result in more energy efficient and sustainable city scale areas, preventing global warming. The highest improvement in the energy efficiency of existing buildings is possible by combining their deep refurbishment and the use of renewable energy sources (RES), where solar energy appears to be the best for application in buildings. Modernizations that provide full electrification seem to be a trend towards providing modern, energy efficient and environmentally friendly, smart buildings. Moreover, switching from an analysis at the single building level to the district scale allows us to develop more sustainable neighborhoods, following the urban energy modelling (UEM) paradigm. Then, it is possible to use the energy cluster (EC) concept, focusing on energy-, environmental- and economic-related aspects of an examined region. In this paper, an actual Polish suburban district is examined using the home-developed TEAC software. The software is briefly described and compared with other computer codes applied for UEM. In this study, the examined suburban area is modernized, assuming buildings’ deep retrofitting, the application of RES and energy storage systems, as well as usage of smart metering techniques. The proposed modernizations assumed full electrification of the cluster. Moreover, the examined scenarios show potential electricity savings up to approximately 60%, as well as GHG emission reduction by 90% on average. It is demonstrated that the proposed approach is a valid method to estimate various energy- and environment-related issues of modernization for actual residential clusters.
The Current Status and Future Potential of Biogas Production from Canada’s Organic Fraction Municipal Solid Waste
Authors: Norouzi Omid , Dutta Animesh
Published: January 2022

With the implementation of new policies supporting renewable natural gas production from organic wastes, Canada began replacing traditional disposal methods with highly integrated biogas production strategies. Herein, data from published papers, Canadian Biogas Association, Canada’s national statistical agency, and energy companies’ websites were gathered to gain insight into the current status of anaerobic digestion plants in recovering energy and resource from organic wastes. The availability of materials prepared for recycling by companies and local waste management organizations and existing infrastructures for municipal solid waste management were examined. Governmental incentives and discouragements in Canada and world anaerobic digestion leaders regarding organic fraction municipal solid waste management were comprehensively reviewed to identify the opportunities for developing large-scale anaerobic digestion in Canada. A range of anaerobic digestion facilities, including water resource recovery facilities, standalone digesters, and on-farm digesters throughout Ontario, were compared in terms of digestion type, digester volume, feedstock (s), and electricity capacity to better understand the current role of biogas plants in this province. Finally, technology perspectives, solutions, and roadmaps were discussed to shape the future in terms of organic fraction municipal solid waste management. The findings suggested that the biogas industry growth in Canada relies on provincial energy and waste management policies, advanced technologies for diverting organic waste from landfills, improving biogas yield using existing pretreatment methods, and educating farmers regarding digester operations.
Formation of ANFO Analogues under Fire Conditions in the Presence of Common Plastics
Authors: Wolny Paweł , Tuśnio Norbert , Lewandowski Artur , Mikołajczyk Filip , Kuberski Sławomir
Published: January 2022

This article is a continuation of a case study in which we presented the results of research on processes generated under fire conditions by mixing molten ammonium nitrate (AN) with selected polymers. Here, we present an analysis of how certain materials, which may frequently appear in farm buildings and are commonly used in the immediate vicinity of humans, can potentially form explosives. The chosen materials include polyamides (PA) from which the wear-resistant machine elements are made (e.g., high-performance gears, wheels of transport trolleys); polyvinyl chloride (PVC) used, i.e., in construction carpentry, electrical insulation, and hydraulic pipes; polystyrene (PS) used, i.e., in insulation and containers; and poly(methyl methacrylate) (PMMA), i.e., so-called organic glass and plexiglass. The research results showed that these seemingly harmless and safe materials, mixed with AN and heated under fire conditions, may turn into explosives and stimulate stored AN. This creates significant risks of an uncontrolled fire progress.
Concept of a Dual Energy Storage System for Sustainable Energy Supply of Automated Guided Vehicles
Authors: Sperling Marvin , Kivelä Tommi
Published: January 2022

Due to the growing number of automated guided vehicles (AGVs) in use in industry, as well as the increasing demand for limited raw materials, such as lithium for electric vehicles (EV), a more sustainable solution for mobile energy storage in AGVs is being sought. This paper presents a dual energy storage system (DESS) concept, based on a combination of an electrical (supercapacitors) and an electro-chemical energy storage system (battery), used separately depending on the required transport distance. Each energy storage unit (ESU) in this DESS is capable of supplying the AGV completely. The concept takes into account requirements for a complex material flow as well as minimizing the energy storage capacity required for the operation of the AGV. An energy flow analysis is performed and further used as a basis to derive three possible circuit concepts for the technical realization. The circuit concepts are compared to other approaches from related work, differentiating the functionality to hybrid energy storage systems (HESS). The functionality of the concepts was validated by mapping the energy flow states to active circuit components. Finally, an approach for implementing the control strategy as a state machine is given, and conclusions for further investigations are drawn.
Driver Monitoring of Automated Vehicles by Classification of Driver Drowsiness Using a Deep Convolutional Neural Network Trained by Scalograms of ECG Signals
Authors: Arefnezhad Sadegh , Eichberger Arno , Frühwirth Matthias , Kaufmann Clemens , Moser Maximilian , Koglbauer Ioana Victoria
Published: January 2022

Driver drowsiness is one of the leading causes of traffic accidents. This paper proposes a new method for classifying driver drowsiness using deep convolution neural networks trained by wavelet scalogram images of electrocardiogram (ECG) signals. Three different classes were defined for drowsiness based on video observation of driving tests performed in a simulator for manual and automated modes. The Bayesian optimization method is employed to optimize the hyperparameters of the designed neural networks, such as the learning rate and the number of neurons in every layer. To assess the results of the deep network method, heart rate variability (HRV) data is derived from the ECG signals, some features are extracted from this data, and finally, random forest and k-nearest neighbors (KNN) classifiers are used as two traditional methods to classify the drowsiness levels. Results show that the trained deep network achieves balanced accuracies of about 77% and 79% in the manual and automated modes, respectively. However, the best obtained balanced accuracies using traditional methods are about 62% and 64%. We conclude that designed deep networks working with wavelet scalogram images of ECG signals significantly outperform KNN and random forest classifiers which are trained on HRV-based features.