bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Estimation of Electrical Characteristics of a Photovoltaic Module Using Regression and Artificial Neural Network Models
Authors: Lee Jonghwan , Kim Yongwoo
Published: December 2022

Accurate modeling of photovoltaic (PV) modules under outdoor conditions is essential to facilitate the optimal design and assessment of PV systems. As an alternative model to the translation equations based on regression methods, various data-driven models have been adopted to estimate the current–voltage (I–V) characteristics of a photovoltaic module under varying operation conditions. In this paper, artificial neural network (ANN) models are compared with the regression models for five parameters of a single diode solar cell. In the configuration of the proposed PV models, the five parameters are predicted by regression and neural network models, and these parameters are put into an explicit expression such as the Lambert W function. The multivariate regression parameters are determined by using the least square method (LSM). The ANN model is constructed by using a four-layer, feed-forward neural network, in which the inputs are temperature and solar irradiance, and the outputs are the five parameters. By training an experimental dataset, the ANN model is built and utilized to predict the five parameters by reading the temperature and solar irradiance. The performance of the regression and ANN models is evaluated by using root mean squared error (RMSE) and mean absolute percentage error (MAPE). A comparative study of the regression and ANN models shows that the performance of the ANN models is better than the regression models.
Design and Implementation of Sigma-Delta ADC Filter
Authors: Wan Renzhuo , Li Yuandong , Tian Chengde , Yang Fan , Deng Wendi , Tang Siyu , Wang Jun , Zhang Wei
Published: December 2022

This paper presents a digital decimation filter based on a third-order four-bit Sigma-Delta modulator. The digital decimation filter is an important part of the Sigma-Delta ADC and is designed to make the Sigma-Delta ADC (Analog-to-Digital Converter) meets the requirements of Signal-to-Noise Ratio (SNR) not less than 120 dB and Equivalent Number of Bits (ENOB) not less than 20 bits. It adopts a three-stages cascaded structure including a Cascaded Integrator Comb (CIC) decimation filter, a Finite Impulse Response (FIR) compensation filter, and a half-band (HB) filter. This structure effectively reduces about 13% multiplier cells and memory cells. The coefficient symmetry technique and CSD (Canonic Signed Digit) coding technique are used to optimize the parameters of the filter, which further reduces the computational complexity. After optimization, the circuit area is reduced by about 15%, and the logic resources are decreased by about 23%. The Verilog hardware description language is used to describe the behavior of the digital decimation filter, and the simulation is carried out based on the VCS (Verilog Compile Simulator) platform. At the same time, the prototype verification is implemented on the Xilinx Artix-7 series FPGA, and the ADC achieves 113 dB SNR and 18.5 bits ENOB. Finally, the Sigma-Delta ADC is fabricated on SMIC 0.18 μm CMOS process with the layout area of 714.8 μm × 628.4 μm and the power consumption of 11.2 mW. The more tests for the fabricated prototypes will be performed in the future to verify that the Sigma-Delta ADC complies with the design specifications.
A Novel Turbo Detector Design for a High-Speed SSVEP-Based Brain Speller
Authors: Tong Changkai , Wang Huali , Cai Jun
Published: December 2022

The past decade has witnessed the rapid development of brain-computer interfaces (BCIs). The contradiction between communication rates and tedious training processes has become one of the major barriers restricting the application of steady-state visual-evoked potential (SSVEP)-based BCIs. A turbo detector was proposed in this study to resolve this issue. The turbo detector uses the filter bank canonical correlation analysis (FBCCA) as the first-stage detector and then utilizes the soft information generated by the first-stage detector and the pool of identified data generated during use to complete the second-stage detection. This strategy allows for rapid performance improvements as the data pool size increases. A standard benchmark dataset was used to evaluate the performance of the proposed method. The results show that the turbo detector can achieve an average ITR of 130 bits/min, which is about 8% higher than FBCCA. As the size of the data pool increases, the ITR of the turbo detector could be further improved.
Protection of Multi-Terminal HVDC Grids: A Comprehensive Review
Authors: Radwan Mohamed , Azad Sahar
Published: December 2022

Multi-terminal HVDC grids facilitate the integration of various renewable resources from distant locations; in addition, they enhance the reliability and stability of the grid. Protection is one of the major obstacles in realizing reliable and secure multi-terminal HVDC grids. This paper presents a comprehensive review of the existing protection schemes for multi-terminal HVDC grids. First, DC fault current stages are demonstrated; in addition, fault analysis studies and the existing fault current calculation methods are reviewed. Then, HVDC grid protection requirements including multi-vendor interoperability conditions are extensively discussed. Furthermore, primary protection algorithms are classified into single- and double-ended schemes, and a detailed comparison between each category is presented such that the distinctive algorithms from each group are highlighted. Moreover, the recent DC reclosing schemes are reviewed highlighting their role in enhancing grid stability and ensuring supply continuity. Finally, available standards for HVDC protection systems alongside their design considerations and procedures are thoroughly outlined. This paper focuses on the recently proposed methods to design reliable protection schemes for multi-terminal HVDC grids and highlights the main advantages and disadvantages associated with them; thus, it offers a beneficial guide for researchers in the HVDC protection field.
Determinants of Reducing Greenhouse Gas Emissions in European Union Countries
Authors: Filipiak Beata Zofia , Wyszkowska Dorota
Published: December 2022

In the literature on the subject, it is argued that tax policy is one of the tools stimulating the transition toward sustainable economies. Public authorities can use two functions for this purpose: fiscal and non-fiscal functions. High emission rates and the rising rapid atmospheric changes that come with them are serious threats to the climate and sustainable development. Reducing greenhouse gas emissions is one of the goals towards which the world strives (including the EU), so as to keep a balance between people’s expectations, economic aspects, and the needs of the environment. Therefore, it is necessary to explain whether, along with other factors, environmental policy and its component “green taxes” can act as a factor in limiting greenhouse gas emissions. The purpose of this article is to seek an answer to the question of whether “green taxes” as an instrument of tax policy are a significant factor influencing climate change by contributing to reducing greenhouse gas emissions. This article attempts to identify the determinants of greenhouse gas emissions (the dependent variable) using the method of linear regression analysis. Multiple linear regression models are used to predict the value of the dependent variable based on the values of the independent variables (identified from the literature). Trading of CO2 emissions was not included in the analysis due to lack of data. The regression analysis was carried out using specialized statistical software (SPSS). The authors negatively verified the hypothesis that environmental taxes are a significant determinant of greenhouse gas emission reductions compared to the analyzed determinants. “Population”, “current and capital transfers for environmental protection”, and “supply, transformation and consumption of solid fossil fuels” are the most important factors influencing greenhouse gas emissions. Changing consumer behavior (as an effect of the non-fiscal function of taxes) appears to be an extremely important factor in reducing greenhouse gas emissions. Hence, the public authorities should promote behaviors conducive to their reduction by means of incentives, and not mainly taxation of negative behavior or fiscal incentives.
Alternative Liquid Fuels for Power Plants and Engines for Aviation, Marine, and Land Applications
Authors: Kuznetsov Geniy , Antonov Dmitrii , Piskunov Maxim , Yanovskyi Leonid , Vysokomornaya Olga
Published: December 2022

The article considers the main tendencies of development of alternative liquid fuels used in aviation, land transport, and for the needs of power generation sector. An overview of the main constraints to the development of alternative fuel technologies in these technical areas was carried out. The main groups of the most promising components and fuel compositions capable of effectively replacing conventional liquid fuels have been generalized. The basic criteria for evaluating alternative fuels are formulated. Environmental indicators of fuel combustion are of paramount importance for aviation. Rheological characteristics, calorific value, and environmental friendliness are critical for land transport engines. The effectiveness of alternative fuels for the power generation sector needs to be assessed in terms of such factors as economic, environmental, rheological, and energy to find an optimal balanced formulation. The list of potential components of alternative liquid fuels is extremely large. For a comprehensive analysis of the efficiency and selection of the optimal composition of the fuel that meets specific requirements, it is necessary to use multicriteria evaluation methods.
Energy Losses Related to Ring Pack Wear in Gasoline Car Engine
Authors: Koszalka Grzegorz , Krzaczek Paweł
Published: December 2022

Decreasing production and rising prices of cars, especially those with electric drive, lead to longer use of cars with internal combustion engines. It can be assumed that in the future, more and more cars powered by such engines with high mileage and therefore high wear will be used. Engine wear leads to reduced efficiency and increased emissions. This paper analyzes the impact of wear of the piston–rings–cylinder system components on energy losses associated with gas leakage from the combustion chamber and friction of the rings against the cylinder liner in a car spark-ignition engine. A ring pack model was used for the analyses. The input data for the simulation were gained in measurements made on the engine test stand and measurements of the wear of the engine components used in the car. The energy losses associated with blow-by in an unworn engine ranged from 1.5% of the indicated work at high load to almost 5% at low load. In the engine after 300,000 km, these losses increased to 2.5% and 7.5%, respectively. Ring friction losses in an unworn engine ranged from 1.5% at high load to 9% at low load. The effect of wear on these losses was smaller. They increased by only 0.1% at high load and 1% at low load.
Clean and Affordable Energy within Sustainable Development Goals: The Role of Governance Digitalization
Authors: Miskiewicz Radoslaw
Published: December 2022

Achieving sustainable development goals depends on governance effectiveness within the penetration of digital technologies in all spheres and levels. Furthermore, the energy sector is a crucial inhibitor of sustainable development that depends on the efficacy of digital public services. In this case, the paper aims at analyzing the impact of e-governance on achieving sustainable development goals, particularly on affordable and clean energy. The object of research is EU countries in the period 2013–2019. The data are compiled from the databases of Eurostat, the World Data Bank, and the Sustainable Development Report. The study applies the following methods: the taxonomy method to measure the e-governance index, the fixed effect, the random effect, and a pooled OLS regression model to check the impact of e-governance on affordable and clean energy. The results outlined the leaders (Estonia, Denmark, Finland, Sweden, Latvia, and Malta) and the outsiders (Romania, Croatia, Greece, Bulgaria, and Poland) in e-governance in 2019. The findings confirm the statistically positive impact of e-governance on extending affordable and clean energy. Thus, improving e-governance by 1 point causes the growth of renewable energy on average by 4.4 points. Furthermore, the industrial structures’ improvement allows increasing renewable energy on average by 0.4 and the trade activization (economic openness) contributes to an increase of renewable energy on average by 0.1. The democracy level does not have a statistically significant impact on achieving sustainable development goals for EU countries. The empirical results show that the countries with high values of e-governance (Sweden, Latvia, Finland, Denmark, and Austria) achieve the highest values of the SDG7 Index Score. Thus, within EU countries, governance digitalization is the strategic inhibitor of SDG achievement.
Utilizing Rooftop Renewable Energy Potential for Electric Vehicle Charging Infrastructure Using Multi-Energy Hub Approach
Authors: Taqvi Syed Taha , Almansoori Ali , Maroufmashat Azadeh , Elkamel Ali
Published: December 2022

Electric vehicles (EV) have the potential to significantly reduce carbon emissions. Yet, the current electric vehicle charging infrastructure utilizes electricity generated from non-renewable sources. In this study, the rooftop area of structures is analyzed to assess electricity that can be generated through solar- and wind-based technologies. Consequently, planning an electric vehicle charging infrastructure that is powered through ‘clean’ energy sources is presented. We developed an optimal modeling framework for the consideration of Renewable Energy Technologies (RET) along with EV infrastructure. After examining the level of technology, a MATLAB image segmentation technique was used to assess the available rooftop area. In this study, two competitive objectives including the economic cost of the system and CO2 emissions are considered. Three scenarios are examined to assess the potential of RET to meet the EV demand along with the Abu Dhabi city one while considering the life-cycle emission of RET and EV systems. When meeting only EV demand through Renewable Energy Technologies (RET), about 187 ktonnes CO2 was reduced annually. On the other hand, the best economic option was still to utilize grid-connected electricity, yielding about 2.24 Mt CO2 annually. In the scenario of meeting both 10% EV demand and all Abu Dhabi city electricity demand using RE, wind-based technology is only able to meet around 3%. Analysis carried out by studying EV penetration demonstrated the preference of using level 2 AC home chargers compared to other ones. When the EV penetration exceeds 25%, preference was observed for level 2 (AC public 3ϕ) chargers.
Investigation of Multiple Degradation Mechanisms of a Proton Exchange Membrane Fuel Cell under Dynamic Operation
Authors: Nguyen Huu Linh , Han Jaesu , Vu Hoang Nghia , Yu Sangseok
Published: December 2022

In this paper, a new voltage aging model for the polymer electrolyte membrane fuel cell (PEMFC), which includes multiple degradation mechanisms for proton exchange membrane fuel cells, is proposed. The model parameters are identified using a curve-fitting procedure based on long-term experimental data for the modular stack under the New European Driving Cycle (NEDC). A good fit was found between the model and experimental data, with R-squared values greater than 0.99 for all simulation cases. Moreover, according to the model sensitivity analysis, the voltage degradation model is most sensitive to load current, followed by time. The effect of operating temperature on performance, voltage degradation, and lifetime is investigated. After 300 h, significant performance loss was detected. When the temperature is raised to 75 °C, voltage degradation becomes worse. Based on the simulated voltage degradation profiles at 55 °C and 75 °C, PEMFCs have reached the end of their useful lives at 1100 h and 600 h, respectively. The simulation model indicates that the model is capable of forecasting how long the fuel cell will last under specified operational conditions and drive cycles.
Optimization of Photovoltaic Panel Array Configurations to Reduce Lift Force Using Genetic Algorithm and CFD
Authors: Khan Asfand Y. , Ahmad Zeshan , Sultan Tipu , Alshahrani Saad , Hayat Khazar , Imran Muhammad
Published: December 2022

Aerodynamic lift force acting on the solar structure is important while designing the counterweight for rooftop-mounted solar systems. Due to their unique configuration, the load estimated for solar structures using international building codes can be either higher or lower than the actual. Computational Fluid Dynamics(CFD) simulations haveproven to be an efficient tool for estimating wind loads on solar panels for design purposes and identifying critical design cases. Computational Fluid Dynamics (CFD) simulations usually require high computation power, and slight changes in geometry to find optimum configuration can be time-consuming. An optimization method to minimize lift force effects on solar photovoltaic (PV) arrays installed on rooftops usesthe Computational Fluid Dynamics (CFD)and genetic algorithms proposed in this paper. The tilt angle and pitch between two rows of solar panels were parameterized, and a genetic algorithm was used to search for aconfiguration resulting in minimum wind lift force acting on the solar photovoltaic plant. Only combinations with a performance ratio >80% were considered. Three different rooftopphotovoltaic (PV) plant layout configurations were analyzed in this research. Two rows of photovoltaic (PV) panel arrays wereconsidered for optimization in the 2D domain using ANSYS Fluent. Results showed that the difference in wind-liftforce between optimized configurations against that with maximum lift force configuration for all three cases above was fifty percent.
Thermodynamic Assessment of the Impact of Selected Plastics on the Energy Parameters of Explosives
Authors: Biegańska Jolanta , Barański Krzysztof , Hebda Kamil , Pytlik Mateusz
Published: December 2022

Global economic development and the associated increase in consumption increase the demand for plastics. The result of these changes is the increase in the share of this group of used plastics in the structure of household waste. An innovative way of managing plastic waste is to use it as a component of a high-energy material. According to the conceptual assumptions, some plastics introduced into the structure of an explosive (Ex) in appropriate amounts can improve the energy parameters of a high-energy material. Modification of the composition of the explosive causes a change in its explosive and operational parameters. It also becomes necessary to develop a method of introducing an additional component. Computer programs for thermodynamic calculations are a tool for modeling the predicted energy parameters of an explosive. The performed simulations and modeling allow for the selection of appropriate compositions for laboratory and “in situ” tests. This reduces the number of field tests performed. This enables the more effective design of new explosive compositions. The use of waste plastics as a corrector of explosive properties may also be pro-environmental in nature through the use of a detonation method of their disposal and will reduce the cost of manufacturing the product. The conducted analyses showed that for three ANFO-type explosives containing 2% polyethylene—PE 2.0, 1% polypropylene—PP 1.0 and 1% polyurethane—PU 1.0, obtained energy parameters similar to ANFO and qualitatively and quantitatively similar structure of post-detonation gases.
Life Cycle Assessment and Techno-Economic Analysis for Anaerobic Digestion as Cow Manure Management System
Authors: Tan Wei En , Liew Peng Yen , Tan Lian See , Woon Kok Sin , Mohammad Rozali Nor Erniza , Ho Wai Shin , NorRuwaida Jamian
Published: December 2022

Clean electricity is generated by the anaerobic digestion of biomass waste. The environmental impacts of various biomass waste feedstocks vary, while co-digestion has been reported to improve anaerobic digestion performance. A consequential life-cycle assessment (LCA) and techno-economic analysis (TEA) are carried out for cow manure waste management for a cow farm. Three scenarios are considered in this study: (S1) mono-digestion of cow manure, (S2) co-digestion of cow manure and maize silage, and (S3) co-digestion of cow manure with cow feed waste, sewage sludge, and returned dairy products. The LCA aims to quantify the environmental impact of each MWh of electricity generated, assuming the plant is located in Malaysia, using OpenLCA software. The TEA economic parameters are quantified and compared between the three scenarios. Net present value (NPV), Internal Return Rate (IRR), and Return of Investment (ROI) are examined. Among the three scenarios, S2 with maize cultivation has a higher environmental impact due to its higher energy requirements. With the integration of closed digestate storage and renewable energy-powered electricity, S3 has the best environmental performance in global warming, eutrophication and acidification. S3 is found to be most economically viable, with MYR 1.28 million NPV, 14% IRR, and 15% ROI, and a Payback Period of 6.56 years with an OPEX of MYR 3491.82/MWh.
Modelling the Energy Production of a Borehole Thermal Energy Storage (BTES) System
Authors: Chicco Jessica , Mandrone Giuseppe
Published: December 2022

Geopolitical developments since February 2022 and the numerous debates on climate change such as the COP27 are pushing for a greater acceleration in decarbonising the energy sector. The use of geothermal energy for thermal energy production and storage in district heating and cooling (DHC) grids may also be a key element in overcoming short-term energy peaks. This work aimed at evaluating the efficiency and performance of one of the most promising underground thermal energy storage systems, which uses boreholes to store heat or cold (BTES). Numerical simulations allowed for understanding how these technologies can be used as backup systems, or when the energy demand overcomes that supplied by conventional heating systems. The knowledge on how to exploit this energy source shows that a continuous heat extraction from the storage volume can meet both the base and peak load requests for several users, with cumulative energy amounting to 476,000 kWh over the first month. This study proved how the integration of these technologies in DHC contexts can contribute to greater energy and economic savings, becoming an efficient and flexible solution to meet the energy demand from the grid, and also as a backup system.
Methodology to Determine the Management of Demand in Recharging Electric Vehicles in Vertically Integrated Markets Includes Photovoltaic Solar Generation
Authors: Toledo-Orozco Marco , Martinez Luis , Quito Hernán , Quizhpi Flavio , Álvarez-Bel Carlos , Morales Diego
Published: December 2022

The high penetration of photovoltaic solar generation and electric vehicles in developing countries and with vertically integrated electricity markets with restrictive regulatory policies enhance demand management and the participation of prosumers in optimizing their resources. In this sense, the research presents a demand management methodology based on the prosumer model for recharging electric vehicles through optimization based on linear programming to minimize recharging costs, considering the stochasticity of the solar radiation variables, vehicular mobility patterns, consumer preferences, and optimal location of charging stations through surveys and predictive tools such as PVsyst and GAMS, in such a way that the energy demand for recharging electric vehicles is met. This way, the methodology reduces power demand peaks and mitigates the economic and technical impact on distribution networks. This case study has been modelled with real information from electric vehicles, distribution networks, and surveys in Cuenca, Ecuador.
Magnetic Vibration in Induction Motor Caused by Supply Voltage Distortion
Authors: Ermolaev Artem , Erofeev Vladimir , Plekhov Aleksandr , Titov Dmitry
Published: December 2022

This article discusses magnetic vibrations in squirrel-cage induction motor stators and provides a mathematical description of the process of their excitation. A model of a 30 kW squirrel-cage induction motor was developed in finite element software. This model considers the motor geometry, material properties and stator winding. The electromagnetic and mechanical processes in the motor during the rotation of the rotor were considered. In the course of this study, currents of various harmonic compositions and amplitudes were applied to the motor windings, which caused magnetic noise, vibration and pulsations of the electromagnetic torque. Magnetic noises, vibrations and pulsations of the electromagnetic torque were investigated in the case of imbalance and harmonic distortions of the supply voltage.
Bio-Oil Derived from Teff Husk via Slow Pyrolysis Process in Fixed Bed Reactor and Its Characterization
Authors: Landrat Marcin , Abawalo Mamo T. , Pikoń Krzysztof , Turczyn Roman
Published: December 2022

Due to the depletion of fossil fuels and the destruction wrought by global warming caused by the combustion of fossil fuels, the search for renewable energy sources has become a major global concern. This study aimed to assess the bio-oil production from teff husk via slow pyrolysis process. The pyrolysis of teff husk took place in a batch reactor at a temperature between 400 °C and 500 °C with a 120 min retention time. At 450 °C, the pyrolysis process produced 32.96 wt.% of optimum bio-oil yield and had a HHV of 25.32 MJ/kg. TGA, FTIR, and SEM-EDX were used to analyze the produced bio-oil to investigate its thermal decomposition, functional groups, and surface morphology with its elemental composition, respectively. Alcohols, aromatic, phenols, alkanes, esters, and ethers were the primary compounds of the bio-oil produced by the slow pyrolysis of teff husk. The HHV of the biochar ranged from 21.22 to 22.85 MJ/kg. As a result, teff husk can be used to make biofuel; however, further bio-oil upgrading is needed for the produced teff husk bio-oil to be used effectively and commercially. Overall, the slow pyrolysis of teff husk offers a chance to produce biofuels with enhanced value that can be used for additional purposes.
Design Modifications for a Thermoelectric Distiller with Feedback Control
Authors: Nasir Mohammad Tariq , Afaneh Diaa , Abdallah Salah
Published: December 2022

In this paper, a modified design for a thermoelectric distiller is proposed, constructed, and tested. The design modifications include adding an inclined cover for the thermoelectric module and a cooling fan. The thermoelectric module and the fan were operated by an open loop or a feedback control to have the desired productivity. As the distiller productivity depends on the operating conditions, these operating conditions are investigated to find the best performance with the highest pure water productivity. Furthermore. a comparison between the closed and the open loop for driving the cooling fan with different operating conditions is conducted. In this work, the mathematical model of the proposed distiller is derived. Experimental results illustrate the robustness of the proposed approach and they show that the suggested thermoelectric distiller with feedback control, for both cases with MPC and PID controllers, can increase pure water productivity by up to 150% when compared with the open loop thermoelectric distiller.
The Effect of Thermal and Moisture Stress on Insulation Deterioration Law of Ionic Contaminated High-Voltage Printed Circuit Board of Electronic Power Conditioner
Authors: Hu Cong , Zheng Wei , Zhao Bin , Fan Yu , Li Hong , Zheng Kun , Wang Gang
Published: December 2022

Since the electronic power conditioner (EPC) is a crucial part applied of a Space Travelling-wave Tube Amplifier (STWTA), the reliability issue must be considered. Of all the failure modes of an EPC, the insulation failure of an EPC in thermal and moist environments is the most serious, and needs special attention. By investigating the influence of contamination, humidity, and temperature on surface insulation resistance (SIR) and surface discharge, we focused on the determination of the insulation failure boundary in an EPC. Considering real working conditions, we used the typical circuit applied in the EPC as the test object. The insulation deterioration phenomenon under different thermal and moisture stress was studied. The results show that: (1) SIR of the samples did not change with contamination levels when the relative humidity (RH) was below 70%. When RH was higher than 75%, the SIR began to vary with temperature and ionic contaminant concentration. (2) Even if the samples were not contaminated (the ionic contamination concentration was less than 1.56 μg/cm2), the deterioration of the SIR still occurred at 85 °C/90% RH. (3) The insulation failure boundary caused by surface discharge, and the degree of electrical erosion were related to humidity, pollution, voltage and temperature. To improve the failure caused by insulation, encapsulation was used. Experiments showed that encapsulation is an effective protection method to prevent insulation deterioration.
Assessment of Reliability Indicators of Combined Systems of Offshore Wind Turbines and Wave Energy Converters
Authors: Ustinov Denis Anatolievich , Shafhatov Ershat Rashitovich
Published: December 2022

Marine renewable sources can make a significant contribution to the development of electrical energy generation and can increase the power supply reliability of mineral complexes. The development of alternative energy sources is happening at a fast pace, and this is due to the improvement of technologies that allow for generating more energy and operating in more extreme conditions, with almost no negative effect on the environment. However, currently, renewable sources are not able to meet all the energy requirements of the platforms. Hence, a key point is to gradually introduce and develop new technologies. This article explores the advantages of combining power generation by wave converters and offshore wind turbines. It investigates the possibilities of improving the combined systems’ reliabilities through justification of their mutual topology and accounting for the shadow effect from the wave installations.
The Influence of Particle Size and Hydrate Formation Path on the Geomechanical Behavior of Hydrate Bearing Sands
Authors: Pandey Mandeep R. , Priest Jeffrey A. , Hayley Jocelyn L.
Published: December 2022

Determining the geomechanical properties of hydrate-bearing sands (HBS), such as strength and stiffness, are critical for evaluating the potential for the economic and safe recovery of methane gas from HBS reservoirs. To date, results from numerous independent laboratory studies on synthesized HBS have shown that strength and stiffness are largely influenced by hydrate saturation, the method adopted for hydrate formation, and to a lesser extent, the confining stresses applied during testing. However, a significant scatter is observed in the data even when these conditions are similar. These include recent studies on natural HBS where sands with larger particle size distribution (PSD) exhibited higher strengths despite lower hydrate saturation. To investigate the impact of PSD, and the role that specific hydrate formation conditions might impose, on the strength and stiffness of HBS, a series of laboratory tests were carried out on sand specimens formed with different particle size distributions and utilizing different approaches for forming gas saturated HBS. The laboratory apparatus included a resonant column drive head to measure the small-strain stiffness of the specimen during hydrate formation, and subsequent drained compressional shearing to capture the stress-strain response of the HBS. Results indicate that the PSD significantly affects both the stiffness evolution (during hydrate formation) and peak strength at failure after formation compared to the effect of the methodology adopted for hydrate formation. These observations improve our understanding of the geomechanical behavior of laboratory-synthesized HBS and allow more robust relationships to be developed between them and natural HBS. This may aid in the development of economic and safe methane gas production methods to help realize the energy resource potential of HBS reservoirs.
Energy, Exergy Efficiency and Thermal-Electrical Production Assessment for an Active Water Heating System Using Four PV/T Module Models
Authors: Hoang Viet Van , Le Hiep Chi , Nguyen Bao The
Published: December 2022

In order to objectively reflect the energy utilization performance of an active water heating system (AWHS) using photovoltaic/thermal (PV/T) modules, this study proposes a new evaluation method based on energy efficiency, exergy efficiency and thermal-electrical output of a system in year-round weather conditions. Four samples of PV/T modules were surveyed to compare and evaluate the effectiveness of the system, called MD1, MD2, MD3 and MD4, respectively. The simulation program was developed to suit four types of PV/T modules and MATLAB was used as the programming language. The water flow through the four PV/T module samples and the hot water tank volume were investigated for the highest exergy efficiency of the system. The final results illustrate that in the weather conditions of Ho Chi Minh City, Vietnam, the system has the highest energy efficiency, exergy efficiency and thermal output when using MD1 with 57.85%, 15.67% and 2.93 kWh/m2/day, respectively, while the system has highest electrical output when using MD3 with 0.8 kWh/m2/day. In addition, under stable conditions ignoring heat loss, MD1 has the highest thermal efficiency with 54.85% and MD3 type has the highest electrical efficiency with 13.67%.
Possibilities of Using Whey Wastes in Agriculture: Case of Turkey
Authors: Sirmacekic Esmanur , Atilgan Atilgan , Rolbiecki Roman , Jagosz Barbara , Rolbiecki Stanisław , Gokdogan Osman , Niemiec Marcin , Kocięcka Joanna
Published: December 2022

Liquid wastes are generated during production in the milk and cheese industries. During cheese production, whey emerges as a liquid product. Researchers define waste as raw material instead of waste alone. Hence, there is no doubt that the use and management of waste will gain greater importance in the upcoming years. This study discusses the use of whey, which is food waste, in agriculture and the benefits derived from it in terms of energy value. Our research was based on the current literature and the amount of whey that emerged in the dairy industry. For this purpose, the existing literature was evaluated to determine how much waste was produced from whey. The total amount of whey waste in Turkey for 2021 was determined. Afterwards, the amount of potential energy was determined in evaluating these wastes. Turkey’s total amount of potential energy obtained from whey waste was calculated as 570.11 × 106 MJ, with 158.36 × 106 kWh as potential electrical energy. Moreover, it was calculated that a total of 158.36 × 106 kWh of electrical energy would meet the electrical energy of 688,548 families of four people for a month. It is also stated that this potential energy will be used in the field of equivalent electrical energy content and agriculture. It is a fact that cheese wastewater, rich in nutrients and organic matter, can be used in agriculture. Whey is used as animal feed in agricultural fertilization activities and the livestock sector. It has also been understood from the literature that it can also be used in biogas production. However, it should not be forgotten that whey released into rivers, water sources, or sewers threatens the environment due to its high protein content. Therefore, by increasing the number of similar studies on the subject, a wide range of wastes, such as whey, can be utilized in the most accurate manner. As a result, environmental protection, conservation of water resources, and energy conservation can be ensured by properly benefiting from whey waste. Considering that the world population will increase in the future, it is a fact that we will need a cleaner environment and more energy. It was concluded that greater importance should be given to waste management practices for a cleaner environment and energy saving.
Identification and Transcriptional Profiling of SNARE Family in Monascus ruber M7 Reveal Likely Roles in Secondary Metabolism
Authors: Meng Chenchen , Zhou Youxiang , Liu Jiao , Chen Fusheng
Published: December 2022

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are the core components that mediate vesicle fusion, and they play an important role in secondary metabolism of filamentous fungi. However, in Monascus spp., one of the traditional medicinal and edible filamentous fungi, the members and function of SNAREs remain unknown. Here, twenty SNAREs in M. ruber M7 were systematically identified based on the gene structure, amino acid structure and phylogenetic analysis and were classified into four subfamilies. We also compared the expression profiles of twenty MrSNAREs in M. ruber M7 and its deletion mutants, ΔmrpigA and ΔpksCT, which could not produce Monascus pigment and citrinin, respectively. The results indicated that these MrSNAREs showed distinct expression patterns in the three strains. Compared to M. ruber M7, the expression levels of Mrtlg2, Mrbet1, Mrgos1 and Mrsec22 remained higher in ΔmrpigA but lower in ΔpksCT, which could be reason to consider them as potential candidate genes involved in secondary metabolism for further functional characterization. Further, the significant upregulation of Mrpep12 and Mrvtil in ΔpksCT is worthy of attention for further research. Our results provide systematic identification and expression profiling of the SNARE family in Monascus and imply that the functions of MrSNAREs are specific to different secondary metabolic processes.
Preliminary Study on Red Wine Aroma: The Volatile Profiles of Six Grape Cultivars in Different Vinification Phases
Authors: Ascrizzi Roberta , Pieracci Ylenia , Melai Bernardo , Cioni Pier Luigi , Narri Patrizio , Flamini Guido , Pistelli Luisa
Published: December 2022

Consumers’ appreciation of wines is mainly driven by their aroma, which is the most important organoleptic characteristic and key attribute. The volatile bouquet derives from the grape berries and from the processing phases of vinification. In the present study, the volatile emission of six grapevine cultivars has been analysed through four phases of vinification: the headspaces of crushed grapes, fermented must, new wine (2 months old), and wine (7 months old) have been sampled and analysed. This showed the evolution of the volatile compounds based on the chemical and mechanical processes involved in the specific vinification phase. Chemometric tools (hierarchical cluster and principal component analyses) have revealed that samples gather in statistical groups based on the vinification phase they belong to, though they maintain an aroma composition that is typical of the grape berry of origin.
Influence of Dietary Inulin on Fecal Microbiota, Cardiometabolic Risk Factors, Eicosanoids, and Oxidative Stress in Rats Fed a High-Fat Diet
Authors: Miralles-Pérez Bernat , Nogués Maria Rosa , Sánchez-Martos Vanessa , Fortuño-Mar Àngels , Ramos-Romero Sara , Torres Josep L. , Ponomarenko Julia , Amézqueta Susana , Zhang Xiang , Romeu Marta
Published: December 2022

The present study examined the influence of inulin on fecal microbiota, cardiometabolic risk factors, eicosanoids, and oxidative stress in rats on a high-fat (HF) diet. Thirty-six male Wistar–Kyoto rats were divided into three dietary groups: standard diet, HF diet, and HF diet + Inulin diet. After 10 weeks, the HF + Inulin diet promoted high dominance of a few bacterial genera including Blautia and Olsenella in feces while reducing richness, diversity, and rarity compared to the HF diet. These changes in fecal microbiota were accompanied by an increased amount of propionic acid in feces. The HF + Inulin diet decreased cardiometabolic risk factors, decreased the amount of the eicosanoids 11(12)-EET and 15-HETrE in the liver, and decreased oxidative stress in blood compared to the HF diet. In conclusion, increasing consumption of inulin may be a useful nutritional strategy to protect against the onset of obesity and its associated metabolic abnormalities by means of modulation of gut microbiota.
Rapid Screening of High-Yield Gellan Gum Mutants of Sphingomonas paucimobilis ATCC 31461 by Combining Atmospheric and Room Temperature Plasma Mutation with Near-Infrared Spectroscopy Monitoring
Authors: Sun Ling , Wang Yazhen , Yue Meixiang , Ding Xialiang , Yu Xiangyang , Ge Jing , Sun Wenjing , Song Lixiao
Published: December 2022

In this study, an efficient mutagenesis and rapid screening method of high-yield gellan gum mutant by atmospheric and room temperature plasma (ARTP) treatment combined with Near-Infrared Spectroscopy (NIRS) was proposed. A NIRS model for the on-line detection of gellan gum yield was constructed by joint interval partial least squares (siPLS) regression on the basis of chemical determination and NIRS acquisition of gellan gum yield. Five genetically stable mutant strains were screened using the on-line NIRS detection of gellan gum yield in the fermentation from approximately 600 mutant strains induced by ARTP. Remarkably, compared with the original strain, the gellan gum yield of mutant strain 519 was 9.427 g/L (increased by 133.5%) under the optimal fermentation conditions, which was determined by single-factor and response surface optimization. Therefore, the method of ARTP mutation combined with the NIRS model can be used to screen high-yield mutant strains of gellan gum and other high-yield polysaccharide strains.
Effects of Far-Infrared Radiation Drying on Starch Digestibility and the Content of Bioactive Compounds in Differently Pigmented Rice Varieties
Authors: Ratseewo Jiranan , Warren Frederick Jame , Meeso Naret , Siriamornpun Sirithon
Published: December 2022

Far infrared radiation (FIR) was applied to six rice varieties with different coloring of the pericarp (purple, red or non-pigment). Changes were determined in amylose content, in gelatinization parameters, in the content of bioactive compounds, in antioxidant activity and in the in vitro digestibility of pigmented rice as affected by FIR. The highest contents of amylose, total phenolic (TPC), total flavonoid (TFC) and total anthocyanins (TAC) were found in the purple and red varieties. Overall, FIR increased TPC, TFC and TAC, including antioxidant capacity. Quercetin and apigenin contents were increased while rutin and myricetin decreased significantly (p < 0.05) in all FIR-dried samples. Dephinidin, cyanidin-3-glucosides and pelargonidin increased after FIR treatment. Mostly, FIR-treated samples were found to have greater gelatinization enthalpy, compared with unheated rice samples. FIR-dried rice showed lower starch digestibility (25–40%) than unheated rice. This research suggested that the specific genotype of rice had the greatest influence on amylose content in pigmented rice, while FIR drying had no further effect. Our results suggest that FIR could enhance the content of the bioactive compounds capable of inhibiting α-amylase, thereby lowering starch digestibility. Hence, FIR may be considered as an appropriate drying method for pigmented rice regarding health benefits.
Effect of Maltodextrin on the Physicochemical Properties and Cooking Performance of Sweet Potato Starch Noodles
Authors: Hu Weiwei , Zhang Wen , Zhang Zhiguo , Shen Shengfa , Lu Guoquan , Wu Weicheng
Published: December 2022

Maltodextrin (MD), the hydrolyzed starch product, is a promising alternative ingredient to improve the quality of starch-based foods. The effects of MD on the physicochemical, microstructural, and cooking properties of sweet potato starch (SPS) noodles, as well as the mechanism of SPS-MD interactions, are discussed. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results indicated that MD at a suitable concentration can improve the ordered structure of SPS-MD gels. The cooking loss showed lower values of 1.47–2.16% at 0.5–2.0 wt% MD. For the texture properties, an increase in hardness and chewiness occurred at first with the addition of MD, followed by a decreasing trend, showing a maximum value at 2.0 wt% of MD. The pasting and thermal results verified the increased stability of the starch granules with MD < 3 wt%. Additionally, SPS formed a solid-like gel with MD, and the main interaction forces between SPS and MD were hydrogen bonding. The scanning electron microscopy results revealed that the higher concentrations of MD (>3 wt%) loosened the gel structure and markedly increased the pore size. These results help us to better understand the interaction mechanism of the SPS-MD complex and facilitate the development of SPS-based gel products.
Changes of Physicochemical Characteristics and Flavor during Suanyu Fermentation with Lactiplantibacillus plantarum and Saccharomyces cerevisiae
Authors: Zhang Qiang , Xiao Naiyong , Xu Huiya , Tian Zhihang , Li Bowen , Qiu Weiqiang , Shi Wenzheng
Published: December 2022

This study investigates the changes of the physicochemical characteristics and flavor of fermented Suanyu (Chinese fermented fish) during fermentation with Lactiplantibacillus plantarum (L. plantarum) and Saccharomyces cerevisiae (S. cerevisiae). The related indicators, including pH, water activity (Aw), volatile base nitrogen (TVB-N), thiobarbituric acid (TBA), free amino acids (FAAs), microbial community, and volatile compounds were determined. L. plantarum fermentation samples (LP) and natural fermentation samples (NF) were used as controls. The pH and Aw of three groups of Suanyu samples decreased continuously through the entire fermentation process. Meanwhile, the TVB-N of three groups of samples increased gradually, while TBA first increased and then decreased. Notably, the pH, Aw, TVB-N, and TBA of MF group samples (inoculated L. plantarum and S. cerevisiae) were significantly lower than the NF group samples. In addition, both TVB-N and TBA of the MF group samples were lower than those of the LP group samples during fermentation, suggesting that combined fermentation could inhibit the growth of undesirable microorganisms more effectively. Lactobacillus were the main bacterial genus of the three group fermented samples during fermentation, and combined fermentation could promote the growth of Lactobacillus more significantly. In addition, the highest content of umami (145.16 mg/100 g), sweet amino acids (405.75 mg/100 g), and volatile compounds (especially alcohols and esters) were found in MF group samples, followed by the NF and LP group samples, indicating that combined fermentation could give Suanyu a better flavor quality. This study may provide a theoretical basis for the industrial production of fermented fish products and the improvement of fermentation technology.