bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Analysis of Cryogenic Cooling System for Electric Propulsion System Using Liquid Hydrogen
Authors: Nam Gi-Dong , Sung Hae-Jin , Ha Dong-Woo , No Hyun-Woo , Koo Tea-Hyung , Ko Rock-Kil , Park Minwon
Published: January 2023

As the demand for eco-friendly energy increases, hydrogen energy and liquid hydrogen storage technologies are being developed as an alternative. Hydrogen has a lower liquefaction point and higher thermal conductivity than nitrogen or neon used in general cryogenic systems. Therefore, the application of hydrogen to cryogenic systems can increase efficiency and stability. This paper describes the design and analysis of a cryogenic cooling system for an electric propulsion system using liquid hydrogen as a refrigerant and energy source. The proposed aviation propulsion system (APS) consists of a hydrogen fuel cell, a battery, a power distribution system, and a motor. For a lab-scale 5 kW superconducting motor using a 2G high-temperature superconducting (HTS) wire, the HTS motor and cooling system were analyzed for electromagnetic and thermal characteristics using a finite element method-based analysis program. The liquid hydrogen-based cooling system consists of a pre-cooling system, a hydrogen liquefaction system, and an HTS coil cooling system. Based on the thermal load analysis results of the HTS coil, the target temperature for hydrogen gas pre-cooling, the number of buffer layers, and the cryo-cooler capacity were selected to minimize the thermal load of the hydrogen liquefaction system. As a result, the hydrogen was stably liquefied, and the temperature of the HTS coil corresponding to the thermal load of the designed lab-scale HTS motor was maintained at 30 K.
Challenges of Establishing Solar Power Stations in Hungary
Authors: Zsiborács Henrik , Vincze András , Háber István , Pintér Gábor , Hegedűsné Baranyai Nóra
Published: January 2023

In the context of the ever-growing demand for energy, especially electric energy, from renewable sources, there has been great interest in photovoltaic energy generation. The speed at which the penetration of photovoltaic technology can grow, however, does not simply depend on supply and demand but also on the various policies and schemes adopted by countries around the world. These, in turn, play decisive roles in investment decisions and determine how projects are approached. Investors in photovoltaic (PV) systems need to be aware of the country-specific risk factors for investments and the regulatory environment. The aim of this research was to explore which managerial, economic and technical aspects should be considered in a causal approach when designing PV power plants with over 50 kW of capacity in the Hungarian regulatory environment for the success of the project. The innovative significance of the study is that it presents a validated, practically usable model for the realization of PV power plant projects in Hungary, which provides an in-depth description of the causal steps of their planning and establishment, based on real-life experience. The novel, practical benefit of the research is that it updates and clarifies the steps necessary for the design of PV power plants, since nowadays there are no current scientific works that provide knowledge of a sufficient depth regarding such projects, so these characteristics need to be investigated.
A Numerical Procedure for Variable-Pitch Law Formulation of Vertical-Axis Wind Turbines
Authors: Rainone Cinzia , De Siero Danilo , Iuspa Luigi , Viviani Antonio , Pezzella Giuseppe
Published: January 2023

A numerical procedure was developed to determine a variable-pitch law that maximized the performance of a vertical-axis wind turbine (VAWT). The methodology was based on the determination, for each blade, of the angle of attack maximizing the stationary aerodynamic efficiency at prescribed azimuthal positions. The angles of attack were determined by means of a panel method with a low computational effort, and the methodology was implemented in Matlab® software (version R2021a) allowing us to achieve in real time a variable-pitch law suitable for the turbine geometry. The variable pitch law was validated by considering its effect on the torque of a 2D model of an H-Darrieus turbine. U-RANS analyses were carried out with a K−ωSST model and a sliding-mesh technique was used to prescribe the blade motion around the shaft and pitch motion. Results showed how the variable-pitch law delayed the dynamic stall and improved the aerodynamic performance considerably.
Techno–Econo–Enviro Energy Analysis, Ranking and Optimization of Various Building-Integrated Photovoltaic (BIPV) Types in Different Climatic Regions of Iran
Authors: Jahangiri Mehdi , Yousefi Yasaman , Pishkar Iman , Hosseini Dehshiri Seyyed Jalaladdin , Hosseini Dehshiri Seyyed Shahabaddin , Fatemi Vanani Seyyed Mohammad
Published: January 2023

Iran is one of the most energy-consuming countries, especially in the construction sector, and more than 40% of its energy consumption is in the construction sector. Therefore, considering the very high potential of Iran in the field of solar energy, the need to pay attention to providing part of the energy required by buildings by solar energy seems necessary. The study of the effect of climate on the performance of a BIPV has not been done in Iran so far. Also, the use of ranking methods using the weighting of parameters affecting the performance of BIPV has not been done so far. The purpose of this study is to investigate the power supply of BIPV connected to the grid in the eight climates of Iran. Technical–economic–environmental energy analyses were performed by HOMER 2.81 software. In order to study different types of BIPV, four angles of 0°, 30°, 60°, and 90° were considered for the installation of solar cells. The effective output parameters of HOMER software were weighted by the Stepwise Weight Assessment Ratio Analysis (SWARA) method based on the opinion of experts, and it was observed that payback time (year) has the highest weight among the studied criteria. Then, different cities were ranked using the evaluation based on distance from the average solution (EDAS) method. The results showed that Jask is the most suitable and Ramsar is the most unsuitable city. Also, the results of the EDAS method were confirmed by Additive Ratio Assessment (ARAS), Weighted Aggregates Sum Product Assessment (WASPAS), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methods.
Characteristics of Electricity Consumption on the Example of Poultry Farming in Poland
Authors: Sierocka Honorata , Zajkowski Maciej , Hołdyński Grzegorz , Sołjan Zbigniew
Published: January 2023

The article presents the results of the analysis of parameters describing electricity consumption in individual phases of the production cycle on a poultry farm. One full broiler rearing cycle on the farm was analyzed. Electrical parameters were tested during the broiler rearing process using a power quality analyzer with a measurement interval of 1 min. During the tests, the analyzer recorded the active and reactive power, phase and line voltage, power factor, and frequency. On the basis of collected data, original indicators describing electricity consumption per chicken wkA, wkQ, and per unit area wiA, wiQ were determined. The regression curves of active and reactive power consumption in particular stages of the cycle were also determined, and the minimum and maximum values of active and reactive power consumption were determined. The accomplished research can be used in planning electricity demand in energy-self-sufficient areas. The presented original indicators can be used to determine power demand on broiler farms, depending on the planned production volume or size of farm buildings.
Modeling and Simulation of Modified MPPT Techniques under Varying Operating Climatic Conditions
Authors: Khodair Doaa , Motahhir Saad , Mostafa Hazem , Shaker Ahmed , Munim Hossam , Abouelatta Mohamed , Saeed Ahmed
Published: January 2023

Enhancing the performance of photovoltaic (PV) systems has recently become a key concern because of the market demand for green energy. To obtain the most possible power from the solar module, it is imperative to allow the PV system to operate at its maximum power point (MPP) regardless of the climatic conditions. In this study, a comparison of distinctive Maximum Power-Point Tracking (MPPT) techniques is provided, which are Perturb and Observe (P&O) and Modified Variable Step-Size P&O, as well as Incremental Conductance (INC) and Modified Variable Step-Size INC, using a boost converter for two types of solar panels. Using MATLAB software, simulations have been performed to assess the efficiency of the solar module under several environmental conditions, standard test conditions (STCs), and sudden and ramp variations in both solar irradiance and temperature. The output power efficiency, time response, and steady-state power oscillations have all been taken into account in this study. The simulation results of the improved algorithms demonstrate an enhancement in the PV module performance over conventional algorithms in many factors including steady-state conditions, tracking time, and converter efficiency. Furthermore, a boost in the dynamic response in monitoring the MPP is observed in a variety of climatical circumstances. Moreover, the proposed P&O MPPT algorithm is implemented in a hardware system and the experimental results verified the effectiveness, regarding both fast-tracking speed and lower oscillations, of the proposed Variable Step-Size P&O algorithm and its superiority over the conventional P&O technique.
A Review of Power Co-Generation Technologies from Hybrid Offshore Wind and Wave Energy
Authors: Ayub Muhammad Waqas , Hamza Ameer , Aggidis George A. , Ma Xiandong
Published: January 2023

Renewable energy resources such as offshore wind and wave energy are environmentally friendly and omnipresent. A hybrid offshore wind-wave energy system produces a more sustainable form of energy that is not only eco-friendly but also economical and efficient as compared to use of individual resources. The objective of this paper is to give a detailed review of co-generation technologies for hybrid offshore wind and wave energy. The proposed area of this review paper is based on the power conversions techniques, response coupling, control schemes for co-generation and complimentary generation, and colocation and integrated conversion systems. This paper aims to offer a systematic review to cover recent research and development of novel hybrid offshore wind-wave energy (HOWWE) systems. The current hybrid wind-wave energy structures lack efficiency due to their design and AC-DC-AC power conversion that need to be improved by applying an advanced control strategy. Thus, using different power conversion techniques and control system methodologies, the HOWWE structure can be improved and will be transferrable to the other hybrid models such as hybrid solar and wind energy. The state-of-the-art HOWWE systems are reviewed. Critical analysis of each method is performed to evaluate the best possible combination for development of a HOWWE system.
Optimisation of Ultrasound Pretreatment of Microalgal Biomass for Effective Biogas Production through Anaerobic Digestion Process
Authors: Paul Roshni , Silkina Alla , Melville Lynsey , Suhartini Sri , Sulu Michael
Published: January 2023

The anaerobic digestion, AD, process presents a solution for sustainable waste management, greenhouse gas mitigation and energy production for growing population needs and requirements. Adopting a biorefinery approach that utilises different feedstock may enhance energy production and support optimisation of the anaerobic digestion process. Algae is a promising feedstock that could be used for energy production via the anaerobic digestion process. Microalgal biomass is rich in carbohydrates and lipids; however, many species of algae exhibit tough cell walls that could also be difficult to digest and may influence or inhibit the efficiency of the AD process. This study concentrated on the comparison of AD remediation of two marine algal biomass species, Tetraselmis suecica and Nannochloropsis oceanica. The two species were pre-treated with an ultrasound technique and compared for their methane production using biochemical methane potential tests. For Tetraselmis, a specific methane production of 0.165 LCH4/KgVS was observed; however, for Nannochloropsis, a value of 0.101 LCH4/KgVS was observed for the samples treated with ultrasound. The BMP results from this study show that among the two micro-algae species tested, Tetraselmis suecica is found to be a better substrate for methane production potential. Contrary to increasing the specific methane production, ultrasound cavitation caused a slight decrease in the specific methane production values for both Nannochloropsis oceanica and Tetraselmis suecica biomass residues. The pre-treatment of the biomass using ultrasound techniques provided comparable results and can be recommended for effective bioenergy production. However, further research is required for the optimisation of the pre-treatment of microalgae and for the integration of microalgal biorefineries for circular economy.
How Can EVs Support High RES Penetration in Islands
Authors: Karakitsios Ioannis , Lagos Dimitrios , Dimeas Aris , Hatziargyriou Nikos
Published: January 2023

The electrification of the transportation sector contributes to a cleaner environment in non-interconnected island (NII) systems or standalone islands. Moreover, e-mobility can significantly contribute to achieving very high renewable energy source (RES) penetration levels in islands, allowing a reduction both in the emissions due to the conventional generation and the system’s cost. Ιncreased RES penetration, however, can pose technical challenges for an island’s system. In order to overcome these challenges, new technologies like grid-forming converters are important. Moreover, the provision of new ancillary services in relation to battery storage systems might be considered, while novel control and protection schemes are needed to ensure secure operation. E-mobility can also contribute to solving technical problems that arise from very high RES penetration by providing frequency containment reserves or reactive power compensation. Since EV charging demand introduces modifications in the system’s load curve, e-mobility may affect the power grid for long-term planning and short-term operation, i.e., line loading and voltages. The application of specifically developed smart charging methodologies can mitigate the relevant grid impact, while effective exploitation of EV–RES synergies can achieve higher RES penetration levels. This paper examines how e-mobility can contribute to increasing RES penetration in islands while considering the technical issues caused. In particular, this paper takes into account the distinct characteristics of NIIs towards the identification of solutions that will achieve very high RES penetration while also addressing the relevant technical challenges (voltage control, frequency control, short circuit protection, etc.). The effect of e-mobility in the power grid of NII systems is evaluated, while smart charging methodologies to mitigate the relevant impact and further increase RES penetration are identified.
Optimal Integration of Photovoltaic Systems in Distribution Networks from a Technical, Financial, and Environmental Perspective
Authors: Guzman-Henao Jhony , Grisales-Noreña Luis Fernando , Restrepo-Cuestas Bonie Johana , Montoya Oscar Danilo
Published: January 2023

Due to the increasing demand for electricity around the world, different technologies have been developed to ensure the sustainability of each and every process involved in its production, transmission, and consumption. In addition to ensuring energy sustainability, these technologies seek to improve some of the characteristics of power systems and, in doing so, make them efficient from a financial, technical, and environmental perspective. In particular, solar photovoltaic (PV) technology is one of the power generation technologies that has had the most influence and development in recent years due to its easy implementation and low maintenance costs. Additionally, since PV systems can be located close to the load, power losses during distribution and transmission can be significantly reduced. However, in order to maximize the financial, technical, and environmental variables involved in the operation of an electrical system, a PV power generation project must guarantee the proper location and sizing of the generation sources. In the specialized literature, different studies have employed mathematical methods to determine the optimal location and size of generation sources. These methods model the operation of electrical systems and provide potential analysis scenarios following the deployment of solar PV units. The majority of such studies, however, do not assess the quality and repeatability of the solutions in short processing times. In light of this, the purpose of this study is to review the literature and contributions made in the field.
Performance Study of Gravity-Type Heat Pipe Applied to Fuel Cell Heat Dissipation
Authors: Jin Lei , Wang Shaohua , Guo Jiachao , Li Haopeng , Tian Xiaoliang
Published: January 2023

A gravity-type heat pipe boiling characteristics test rig was constructed to solve the heat dissipation problem of fuel cells during operation. The boiling heat transfer characteristics of water in a parallel plate under negative pressure at different inclination angles and heat flow density input are investigated. The results show that: First, the gravity-type heat pipe can dissipate some heat and it is possible to use it for fuel cell heat dissipation. Second, with a certain range of heat flow density, the temperature of all parts of the plate is about 80 °C, with a small temperature difference, which is conducive to the safe operation of the fuel cell. Third, the heat flow density is in the range of 2222~3111 W·m−2, the temperature difference is large, and the outlet temperature is greater than 80 °C, which exceeds the operating temperature of the fuel cell, and the power-type heat pipe should be used for heat dissipation. Fourth, the average temperature of the plate placed at an inclination angle of 45°~60° is lower compared to other angles, and the temperature is evenly distributed. On the one hand, the conclusions reveal the characteristics of boiling heat exchange under negative pressure conditions of water inside the flat plate and, on the other hand, provide a reference for designing heat pipe systems for fuel cell heat dissipation.
The Circular Economy in the Management of Waste from Leather Processing
Authors: Wrzesińska-Jędrusiak Edyta , Czarnecki Michał , Kazimierski Paweł , Bandrów Paulina , Szufa Szymon
Published: January 2023

The tanning industry generates significant amounts of solid waste and post-production wastewater, which should be managed in accordance with the principles of the circular economy. Waste is generated at various technological stages of production. This comprises mainly solid waste and leachate. A comprehensive solution to the problem of disposal of this waste is very important from economic and environmental points of view. This work presents research for a technological production line designed for the comprehensive processing of post-production residues. In the present paper, the authors present an analysis related to the possibility of processing leather flesh side (mizdra) as a substrate for methane fermentation. The study showed an increased biogas production from solid waste after enzymatic hydrolysis up to 248 Nm3/Mg. Preliminary research on the system designed for pre-treatment of sewage from the technological line is also presented. The study showed a COD reduction of more than 30%. The possibility of energy management of the solid fraction directly from the processes carried out is demonstrated.
Methane Production from Confectionery Wastewater Treated in the Anaerobic Labyrinth-Flow Bioreactor
Authors: Dębowski Marcin , Kisielewska Marta , Kazimierowicz Joanna , Zieliński Marcin
Published: January 2023

Production and consumption of confectionery products have increased worldwide, thus, effective management of wastewater produced is now an important issue. The confectionery high-load sewage was explored for biogas production in an innovative-design anaerobic reactor with labyrinth flow. The experimental studies were focused on determining the best technological parameters of anaerobic digestion for the effective removal of pollutants and obtaining high CH4 production efficiency. It was found that organic loading rate (OLR) of 5.0–6.0 g COD/L·d contributed to the highest CH4 generation of 94.7 ± 6.1 to 97.1 ± 5.1 L CH4/d, which corresponded to a high COD removal of 75.4 ± 1.5 to 75.0 ± 0.6%. Under such conditions the FOS/TAC ratio was below 0.4, indicating reactor stability, and pH was on the level of 7.15 ± 0.04 at OLR 5.0 g COD/L·d and 7.04 ± 0.07 at OLR 6.0 g COD/L·d.
The Role of Organic Compounds in Dye-Sensitized and Perovskite Solar Cells
Authors: Coppola Carmen , Parisi Maria Laura , Sinicropi Adalgisa
Published: January 2023

Developing solar energy conversion devices is one key driver of the energy transition pathway [...]
Efficiency of Chemical Pretreatment of Sugar Beet Pulp Biomass Intended to Energy Production via Biological Processes
Authors: Pawłowska Małgorzata , Zdeb Magdalena , Nieścioruk Monika
Published: January 2023

Environmentally friendly anaerobic digestion (AD) of lignocellulose-based materials is becoming an increasingly popular alternative to non-renewable energy sources. It also corresponds with the principles of sustainable development. The structure of lignocellulosic materials, which is resistant to biodegradation, requires using pretreatment methods prior to subjecting them to anaerobic processes. The aim of the study was to evaluate the influence of temperature and type of hydrolyzing agent on the efficiency of chemical pretreatment of sugar beet pulp. Biomass samples soaked in distilled water and 0.05 M solutions of NaOH and H2SO4 were left for 20 h, both at room temperature (22 °C) and in a thermostated chamber (50 °C). The changes in pH, electrolytic conductivity (EC), concentration of volatile fatty acids (VFA), dissolved chemical oxygen demand (COD), and phenols were analyzed. The concentration of CODdissolved, demonstrating the efficiency of pretreatment methods, obtained after alkaline hydrolysis conducted at 22 °C was almost at the same level as in the case of acid hydrolysis carried out at 50 °C: 3451 mg dm−3 and 3608.5 mg dm−3, respectively. Hydrolysis carried out in a NaOH solution at 22 °C appears to be the most economical option for sugar beet pulp pretreatment out of all analyzed ones, as there is no need to increase expenditure on heating samples.
New Method of Degradation Process Identification for Reliability-Centered Maintenance of Energy Equipment
Authors: Zadiran Konstantin , Shcherbakov Maxim
Published: January 2023

Advancements in energy technologies created a new application for gas turbine generators, which are used to balance load. This usage also brought new challenges for maintenance because of harsh operating conditions that make turbines more susceptible to random failures. At the same time, reliability requirements for energy equipment are high. Reliability-centered maintenance based on forecasting the remaining useful life (RUL) of energy equipment, offers improvements to maintenance scheduling. It requires accurate forecasting methods to be effective. Defining stages in energy equipment operation allows for the improvement of quality of data used for training. At least two stages can be defined: normal operation and degradation process. A new method named Head move—Head move is proposed to robustly identify the degradation process by detecting its starting point. The method is based on two partially overlapping sliding windows moving from the start of operation to the end of life of the energy equipment and Kruskal-Wallis test to compare data within these windows. Using this data separation, a convolutional neural network-based forecasting model is applied for RUL prediction. The results demonstrate that the proposed degradation process identification (DPI) method doubles the accuracy when compared to the same forecasting model but without degradation process identification.
Microbial Fuel Cell Performance Boost through the Use of Graphene and Its Modifications—Review
Authors: Starowicz Adam , Zieliński Marcin , Rusanowska Paulina , Dębowski Marcin
Published: January 2023

The conversion of chemical energy contained in organic matter into electricity has become an object of interest for many scientists worldwide. This technology is used in microbial fuel cells (MFC). Apart from generating electrical energy, these cells can be used simultaneously for wastewater treatment. Although the technology is constantly being improved, currently functioning microbial fuel cells cannot provide appropriate output parameters to use on an industrial scale. One of the barriers is so-called extracellular electron transfer, which in turn depends on the electrode type used, its material, shape, and size. According to current literature, carbon, graphite, stainless steel, and ceramics are the most frequently used electrode materials. However, more and more often, scientists are turning to other, unusual materials, the production of which uses the newest technologies, and one of them is graphene. This material is modified in different ways and connected with other materials, and the results of this seem to be very promising. Scientists manage to get a higher level of extracellular electron transfer and, hence, higher output parameters of the whole system. This article describes chosen technologies and attempts made by scientists worldwide to use graphene in MFC and their results.
Influence of a Hybrid MPPT Technique, SA-P&O, on PV System Performance under Partial Shading Conditions
Authors: Abo-Khalil Ahmed G. , El-Sharkawy Ibrahim I. , Radwan Ali , Memon Saim
Published: January 2023

The electricity sector has been undergoing profound transformations. In particular, the Portuguese self-consumer regime has allowed customers of the medium and low voltage electricity grid to be producers/consumers of electricity, actively contributing to greater energy efficiency. In this context, the energy that comes from the sun is not used to its maximum. In addition, photovoltaic cells have a characteristic operating curve (voltage vs. current), in which any operating point is reflected. Within this curve, there is a particular point known as the maximum power point (MPP) at which the cell supplies the maximum power output to a load. If the cell does not operate at this point, it has lower efficiency values. To harness maximum power under standard and dynamic shading conditions, there are various techniques of low complexity for capturing maximum power. We present a maximum power point tracking (MPPT) algorithm capable of dealing with the problem of partial shading. This algorithm involves modifying one of the most used algorithms within photovoltaic systems, known as P&O, using a simulated annealing (SA) algorithm. P&O is often used due to its straightforward implementation, but it is susceptible to partial shade conditions. Sampling was added to this algorithm to a better approach to the point of maximum power using the SA, and then to attain a more precise convergence with P&O. Implementing a maximum power point tracking method under partial shading was the major goal of this study.
Energy Indicators for Enabling Energy Transition in Industry
Authors: Franco Alessandro , Miserocchi Lorenzo , Testi Daniele
Published: January 2023

Energy transition is a fundamental process in the move towards sustainable development, but in industry, it is complicated by the remarkable sectoral heterogeneity. Fostering the realization of energy transition in the industrial sector requires the characterization of its energy dimension, in terms of energy mixes and end-uses as the determinants of transition pathways, and energy solutions and tools as the enablers of this transition paradigm. We observe that the suitability of tools for energy analysis depend on trade-offs between comprehensiveness, ease of use, robustness, and generalization ability. In this regard, we discuss the appropriateness of energy indicators and provide an overview of indicator typologies, methodological issues, and applications for energy performance evaluation and improvement. With reference to the dairy processing industry, selected as a representative industrial branch, we outline current and desirable energy benchmarking applications and exemplify the effectiveness of energy indicators in the quantification of the potential of energy solutions. The obtained results are promising and suggest that researchers should further explore the novel applications of energy indicators for energy performance improvement. To foster the establishment of energy indicators in industrial practice and energy policies, we remark that cooperation between industrial stakeholders is essential.
Life Cycle Analysis of Innovative Technologies: Cold Formed Steel System and Cross Laminated Timber
Authors: Iuorio Ornella , Gigante Antonio , De Masi Rosa Francesca
Published: January 2023

Reducing the embodied and operational energy of buildings is a key priority for construction and real estate sectors. It is essential to prioritize materials and construction technologies with low carbon footprints for the design of new buildings. Off-site constructions systems are claimed to have the potential to deliver a low carbon build environment, but at present there are a lack of data about their real environmental impacts. This paper sheds lights on the environmental performance of two offsite technologies: cold formed steel and cross laminated timber. Specifically, the environmental impacts of a CFS technology are discussed according to six standard impact categories, which includes the global warming potential and the total use of primary energy. The study is based on a detailed cradle to gate life cycle analysis of a real case study, and discusses the impacts of both structural and non-structural components of CFS constructions. As a useful frame of reference, this work compares the environmental impacts of 1 m2 of walls and floors of CFS technology with those of cross laminated timber, which is spreading as innovative off-site technology for the development of nearly zero energy buildings, and a conventional reinforced masonry technology, which is largely adopted in the Italian construction sector. The paper concludes with the necessity to optimize structural systems to reduce the overall embodied carbon impacts.
Economic Assessment of Polypropylene Waste (PP) Pyrolysis in Circular Economy and Industrial Symbiosis
Authors: Zabaniotou Anastasia , Vaskalis Ioannis
Published: January 2023

Plastic waste has a high energy content and can be utilized as an energy source. This study aims to assess the economic feasibility of polypropylene plastic waste (PP) pyrolysis. A literature review was carried out to determine the optimal pyrolysis conditions for oil production. The preferred pyrolysis temperature ranges from 450 °C to 550 °C, where the oil yields vary from 82 wt.% to 92.3 wt.%. Two scenarios were studied. In the first scenario, pyrolysis gas is used for the pyrolysis heating needs, whereas in the second scenario, natural gas is used. An overview of the economic performance of a pyrolysis plant with a capacity of 200,000 t/year is presented. Based on the results, the plant is economically viable, as it presents high profits and a short payback time for both scenarios considered. Although the annual revenues are smaller in scenario 1, the significant reduction in operating costs makes this scenario preferable. The annual profits amount to 37.3 M€, while the return on investment is 81% and the payback time is 1.16 years. In scenario 2, although the plant is still feasible and shows high profitability, the annual profits are lower by about 1.5 M€, while the payback time is 1.2 years.
Numerical Simulation on Effect of Separator Thickness on Coupling Phenomena in Single Cell of PEFC under Higher Temperature Operation Condition at 363 K and 373 K
Authors: Nishimura Akira , Mishima Daiki , Toyoda Kyohei , Ito Syogo , Kolhe Mohan Lal
Published: January 2023

In hydrogen energy systems, the polymer electrolyte fuel cell (PEFC) is an important component. The purpose of this study is to clarify the effect of separator thickness (s.t.) in PEFC on the distributions of mass such as H2, O2, H2O and current density when PEFC is operated at 363 K and 373 K. The relative humidity (RH) of supply gases also impacts the operation. The numerical simulation (using a 3D model) with COMSOL Multiphysics has been conducted to analyze the characteristics of PEFC. It has been observed that the molar concentration of H2 using s.t. of 2.0 mm is smaller compared with the thinner s.t. cases at the initial operation temperature of a cell (Tini) = 363 K and 373 K. The molar concentration of O2 using s.t. of 2.0 mm is smaller compared with the thinner s.t. cases at Tini = 373 K, as well as the case for the RH of supply gases at the anode of 40%RH and cathode of 40%RH (A40%RH/C40%RH) irrespective of Tini. Additionally, it has been clarified that the molar concentration of H2O maintains a low value along with the gas channel at Tini = 373 K using s.t. of 1.5 mm and 1.0 mm. Moreover, it has been clarified that the current density using s.t. of 2.0 mm is the highest among the different s.t. irrespective of Tini, which is the most remarkable in the case of A40%RH&C40%RH.
Development of Red Ceramic Pigments with Perovskite Structure Prepared through a Traditional Route
Authors: Miguel Eva , Carda Castelló Juan Bautista , Nebot-Díaz Isaac
Published: January 2023

Solid solutions of ceramic pigments of red shade have been synthesized based on YAlO3 perovskite structure doped with chromium by means of conventional synthesis; that is, the “ceramic route”. To optimize this synthesis, an emphasis has been made on the study of stoichiometry, calcination conditions and mineralizer incorporation. Various studies have demonstrated the high stability of perovskite structures, which ensures stable coloration at high temperatures. This is a highly important factor in the ceramic sector, given the scarcity of red glazes functional at temperatures close to those required of porcelain stoneware and their environmental constraints. Such a limitation makes it impossible in the European community to manufacture using toxic materials such as Se and Cd (cadmium sulfoselenide) that offer interesting colors at low temperatures. Pigments have been synthesized within the Y1−xCrxAlO3, YCrxAl1−xO3 and Y1−xAl1−yCrx+yO3 chromium-doped systems in molar ratios between n = 0.01 molar and n = 0.10 molar. The pigments obtained have been characterized by X-ray diffraction to identify the crystalline phases responsible for the shade; that is, the formation of the perovskite crystalline structure YAlO3 responsible for the red shade, together with lateral phases of garnet Y3Al5O12 of lower intensity. Visible ultraviolet spectrophotometry shows absorption bands corresponding to Cr(III) in octahedral position and the appearance of Cr(IV) in both octahedral and tetrahedral positions. The morphology of the samples was studied using a scanning electron microscope, obtaining information from the secondary and back scattered electrons. The viability of its use in ceramic glazes was verified after applying them mixed at 4% by weight in a glaze to an industrial porous single-firing cycle, collecting the L*a*b* chromatic coordinates using a visible ultraviolet spectrophotometer based on the CIE L*a*b* system, giving rise to red colorations.
Spatial and Temporal Evolution and Driving Mechanisms of Water Conservation Amount of Major Ecosystems in Typical Watersheds in Subtropical China
Authors: Li Yiting , Kong Ming , Zang Chuanfu , Deng Jinglin
Published: January 2023

The water conservation function of ecosystems is a research hot spot in the field of water resources, and it is also an important ecological service function of terrestrial ecosystems and a key point in eco-hydrology research. With the increasing frequency of human activities and climate change, how to reveal the response of ecosystem water conservation function to the changing environment is a scientific problem that needs to be urgently addressed in ecological hydrology research. To reveal the eco-hydrological processes under the changing environment, this study was based on the distributed hydrological model (SWAT) and used water conservation amount (WCA) as an indicator to assess the water conservation capacity of ecosystems. Scenario analysis and statistical analysis were also used to determine the spatial and temporal evolution of the WCAs of farmland, forest, and grassland ecosystems under a changing environment and to further investigate the influence mechanisms of land use change and climate change on the WCA. The findings show that (1) the climate conditions in the Hanjiang watershed have determined the distribution pattern of the ecosystem’s WCA. The spatial distribution patterns of the WCA of each ecosystem differed significantly between the dry season and the wet season. Under the combined influence of human activities and climate change, there was no significant change in the spatial distribution pattern of the WCA. (2) Climate change patterns, which were dominated by precipitation and influenced by evapotranspiration, determined the changes in the WCA of ecosystems. In addition, there were significant spatial differences in the response of the watershed WCA under changing environments in the dry season. Differences in land use type and local climate change were the main reasons for such differences. (3) There were differences in the WCA and the response to changing environments among ecosystems. Forest ecosystems had the highest WCA; grassland ecosystems were the most sensitive to land use change. This study can provide a theoretical basis for alleviating the increasingly serious water resource problems in the basin and ensuring water and ecological security in the basin.
Transfer Functions and Linear Distortions in Ultra-Wideband Channels Faded by Rain in GeoSurf Satellite Constellations
Authors: Matricciani Emilio , Riva Carlo
Published: January 2023

Because of rain attenuation, the equivalent baseband transfer function of large bandwidth radio-links will not be ideal. We report the results concerning radio links to/from satellites orbiting in GeoSurf satellite constellations located at Spino d’Adda, Prague, Madrid, and Tampa, which are all sites in different climatic regions. By calculating rain attenuation and phase delay with the Synthetic Storm Technique, we have found that in a 10-GHz bandwidth centered at 80 GHz (W-Band)—to which we refer to as “ultra-wideband-, both direct and orthogonal channels will introduce significant amplitude and phase distortions, which increase with rain attenuation. Only “narrow-band” channels (100~200 MHz) will not be affected. The ratio between the probability of bit error with rain attenuation and the probability of bit error with no rain attenuation increases with rain attenuation. The estimated loss in the signal-to-noise ratio can reach 3~4 dB. All results depend on the site, Tampa being the worst. To confirm these findings, future work will need a full Monte Carlo digital simulation.
Synthesis of High-Efficiency, Eco-Friendly, and Synergistic Flame Retardant for Epoxy Resin
Authors: Gao Jiaxiang , Wu Hanguang , Xiao Yang , Ma Wenjing , Xu Fei , Wang Rui , Zhu Zhiguo
Published: January 2023

It remains a challenge to prepare flame-retardant composites via the addition of a low content of flame retardant. In this work, a novel DOPO-functionalized reduced graphene oxide hybrid (DOPO-M-rGO) flame-retardant system was synthesized for epoxy resin (EP). The phosphorus-nitrogen-reduced graphene oxide ternary synergistic effect provided DOPO-M-rGO with high flame-resistance efficiency in EP; thus, the EP-based composite exhibited superior fire-resistant performance at extremely low DOPO-M-rGO loading. The limiting oxygen index (LOI) of the EP-based composite was increased from 25% to 32% with only 1.5 wt% DOPO-M-rGO addition, and the peak heat release rate (pHRR), total heat release (THR), and total smoke production (TSP) were significantly decreased by 55%, 30%, and 20%, respectively. In addition, as a halogen-free flame-retardant system, DOPO-M-rGO presents great application potential as an eco-friendly additive for the flame-resistance improvement of thermosetting polymer materials.
Insights into the Relationship between Intestinal Microbiota of the Aquaculture Worm Sipunculus nudus and Surrounding Sediments
Authors: Li Junwei , Chen Suwen , Wu Peng , Zhu Changbo , Hu Ruiping , Li Ting , Guo Yongjian
Published: January 2023

Sipunculus nudus is an important intertidal aquaculture species that can ingest organic matter from the surface sediment and shows a high transportation capacity in sediment. However, little is known about the influence of intertidal aquaculture species on the sediment microbial community and the exchange of microbiota between the intestine and the surrounding sediment. In this study, the microbial communities in the intestine of S. nudus and three kinds of surrounding sediments were analyzed using high-throughput sequencing of the 16S rRNA gene amplicon, and the relationships between different communities were examined. Principal coordinate analysis and ANOSIM/Adonis analysis showed that the microbial communities of worm intestine samples were significantly different from those of surrounding sediments (p < 0.05). Meanwhile, compared with the sediment samples, the microbial α-diversity was significantly lower in the intestinal samples. Although the relative abundances of Proteobacteria and Cyanobacteria were high in all samples, three phyla (Bacteroidetes, Gemmatimonadetes, and Latescibacteria) showed a great difference between the four groups, as the abundances of the three phyla were significantly lower in the intestinal samples. Moreover, several microbial interactions were found between the worm intestine and surrounding sediments. BugBase functional prediction analysis indicated that the oxygen status of the sediment and the intestine was changed by bioturbation by the worm. Therefore, the microenvironment and microbial community in sediment were affected by the activity of S. nudus in the intertidal aquaculture zone.
Illegal, Unreported, and Unregulated Fishing Governance in Disputed Maritime Areas: Reflections on the International Legal Obligations of States
Authors: Chen Xidi , Xu Qi , Li Lun
Published: January 2023

Illegal, unreported, and unregulated (IUU) fishing in the disputed maritime areas causes significant damage to the marine ecology and authorized fisheries, increases the risk of conflicts among disputed states, and violates human rights at sea. Both unilateral measures and cooperative governance for IUU fishing are often inadequate in these areas. In light, this study aims to clarify the regulatory obligations of relevant states and explore feasible solutions based on international cooperation to promote IUU governance in disputed areas worldwide. The rapidly evolving international fisheries legal framework requires that states, such as coastal states, flag states, port states, or market states, fulfill their respective obligations to prevent and deter IUU and that the presence of disputes in a specific maritime area does not typically constitute grounds for derogation from these obligations or exemption from possible state responsibility. However, the implications of the conflicting claims in disputed maritime areas should be taken into consideration while interpreting and applying international legal rules. Therefore, this study suggests that regional and inter-regional cooperation is necessary for states to fulfill their obligations to regulate IUU fishing and prevent state responsibilities under international law. Parties to the dispute, as well as third parties, are encouraged to participate in the cooperative mechanism in order to coordinate legislative and enforcement measures and advance the institutionalization of IUU fishing regulation in the disputed maritime areas, which will not only advances the effective governance of IUU fishing but also reduces tensions among the disputing states and contributes to the peaceful settlement of the dispute.
Design and Concept of Renewable Energy Driven Auto-Detectable Railway Level Crossing Systems in Bangladesh
Authors: Iftekharuzzaman Iftekharuzzaman , Ghosh Susmita , Basher Mohammad , Islam Mohammad , Das Narottam , Nur-E-Alam Mohammad
Published: January 2023

Bangladesh’s railway system mostly uses typical manual railway crossing techniques or boom gates through its 2955.53 km rail route all over the country. Accidents frequently happen at railway crossings due to the lack of quickly operating gate systems, and to fewer safety measures at the railway crossing as well. Currently, there are very few automatic railway crossing systems available (without obstacle detectors). Additionally, all of them are dependent on the national power grid, without a backup plan for any emergency cases. Bangladesh is still running a bit behind in generating enough power for its consumption; hence, it is not possible to have a continuous power supply at all times all over the countryside. We aim to design and develop a smart railway crossing system with an obstacle detector to prevent common types of accidents at railway crossing points. We use two infrared (IR) sensors to operate the railway crossing systems, which are controlled by an Arduino Uno. This newly designed level crossing system is run with the help of sustainable renewable energy, which is cost-effective and eco-friendly, and applied under the national green energy policy towards achieving sustainable development in Bangladesh as a part of the global sustainable goal to face climate change challenges. We have summarized the simulated the results of several renewable energy sources, including a hybrid system, and optimized the Levelized Cost of Energy (LCOE) and the payback periods.
Bamboo Nanocellulose/Montmorillonite Nanosheets/Polyethyleneimine Gel Adsorbent for Methylene Blue and Cu(II) Removal from Aqueous Solutions
Authors: Zhang Xuelun , Li Feng , Zhao Xiyu , Cao Jiwen , Liu Shuai , Zhang You , Yuan Zihui , Huang Xiaobo , De Hoop Cornelis F. , Peng Xiaopeng , Huang Xingyan
Published: January 2023

In recent years, the scarcity of pure water resources has received a lot of attention from society because of the increasing amount of pollution from industrial waste. It is very important to use low-cost adsorbents with high-adsorption performance to reduce water pollution. In this work, a gel adsorbent with a high-adsorption performance on methylene blue (MB) and Cu(II) was prepared from bamboo nanocellulose (BCNF) (derived from waste bamboo paper) and montmorillonite nanosheet (MMTNS) cross-linked by polyethyleneimine (PEI). The resulting gel adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS), etc. The results indicated that the MB and Cu(II) adsorption capacities of the resulting gel adsorbent increased with the solution pH, contact time, initial concentration, and temperature before equilibrium. The adsorption processes of MB and Cu(II) fitted well with the fractal-like pseudo-second-order model. The maximal adsorption capacities on MB and Cu(II) calculated by the Sips model were 361.9 and 254.6 mg/g, respectively. The removal of MB and Cu(II) from aqueous solutions mainly included electrostatic attraction, ion exchange, hydrogen bonding interaction, etc. These results suggest that the resulting gel adsorbent is an ideal material for the removal of MB and Cu(II) from aqueous solutions.