bluuebunny/crossref_metadata_2025 huggingface dataset:
From Direct Solar Gain to Trombe Wall: An Overview on Past, Present and Future Developments
Authors: Szyszka Jerzy
Published: November 2022

The energy crisis, the risk of interruptions or irregular supplies of conventional energy carriers, and the need to protect the environment stimulate the search for new solutions to improve the heat balance of buildings with the use of solar energy. In this paper, direct and indirect solar gain systems integrated with the building envelope are discussed. In the context of the identified operational problems, the evolution of the classic Trombe wall was shown in the period 1967–2022. Modifications to the windows and Trombe wall proposed in the reviewed works can significantly reduce the risk of an insufficient supply of heat in the winter season. This review also indicates the impact of climate conditions on the decision-making process involved in the selection of the Trombe wall design with respect to energy–effects optimization. The insufficient thermal insulating capacity of Trombe walls has been diagnosed as the reason why they do not enjoy much popularity in cold and moderate climates. As the main directions of development of solar gains systems, the search for solutions that maximize solar gains while ensuring high standards of thermal insulation and the implementation of intelligent technologies were indicated.
Effect of Rotational Speed on the Structural, Morphological, and Optical Properties of Biosynthesized Nickel Oxide Thin Films for Selective Solar Absorber Nanocoatings
Authors: Gebretinsae Henok G. , Tsegay Meresa G. , Welegergs Giday G. , Maaza Malik , Nuru Zebib Y.
Published: November 2022

This article presents a simple and low-cost green synthesized single-layer NiO selective solar absorber nanocoating prepared by spin coating on a Cu substrate at different rotational speeds (RS). The effects of substrate RS on the structural, morphological, chemical, and optical properties of the NiO nanocoatings were thoroughly investigated. The XRD results reveal the formation of pure diffraction peaks indexed to face-centered cubic NiO nanocoatings. SEM confirmed the uniform distribution of the NiO thin films with a nanosphere-like structure and the influence of RS variation on the formation of NiO nanostructures. EDS and XPS confirmed the presence of Ni and O in the green synthesized NiO coatings. AFM showed homogeneous nanopillar-like NiO thin films with the average surface roughness decreasing from 13.6 to 9.06 nm as the RS increased from 700 to 1300 RPM. Raman spectroscopy of the nanocoatings showed normal modes related to longitudinal optical and transverse optical phonons, and a combination of both, which implies the presence of a defect-rich or anti-ferromagnetically ordered NiO film responsible for the occurrence of more scattering peaks. UV–Vis–NIR and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the optical properties of the nanocoatings. The green synthesized NiO nanocoatings deposited at 700 RPM exhibited excellent solar absorptance (α) of 0.92 and low thermal emittance (ɛ) of 0.11. The optical properties of the selective materials obtained in the present work were correlated with the non-stoichiometric nature of the spin-coated sample, multiple reflections, and interference-induced light absorption on the green synthesized surface. These results suggest that the NiO thin films prepared through this simple and environmentally benign green synthesis method can be promising candidates for efficient solar selective absorbers.
Study on Fatigue Characteristics of Axial-Flow Pump Based on Two-Way Fluid–Structure Coupling
Authors: Bai Yalei , Wu Donglei
Published: November 2022

When an axial-flow pump is running, there is a very complex flow inside the runner. Based on the two-way fluid–structure coupling method, this paper simulated the forward and reverse operating conditions of an axial-flow pump and calculated the dynamic stress distribution on the blade surface. The stress load spectrum was loaded onto the blade, and fatigue characteristic analysis was carried out to obtain the fatigue life and damage of the blade. This research shows the following: under different working conditions, the dynamic stress is concentrated at the root of the blade, and its amplitude decreases with the increase in the flow rate; at the same time, the change in stress with time shows a periodic change law. Under the working conditions of the turbine, the main frequency is the rotational frequency, and the secondary frequency is composed of multipliers of the rotational frequency, which is obviously affected by the number of blades; the fatigue damage and stress distribution are consistent, and the damage is the most serious at the stress concentration point. The research results of this paper can provide theoretical guidance for the structural design and safe operation of axial-flow pumps.
Improving Structural Safety of L-Type Flange Joint for Wind Towers
Authors: Tran Thanh-Tuan , Kang Sangkyun , Lee Daeyong
Published: November 2022

This paper focuses on the design modification of L-type flange joint geometry in wind towers, aiming to enhance its structural safety. For this aim, current design issues of existing flange joints are discussed. The numerical simulations indicate that the threaded bolt and flange-to-shell junction are critical locations where failure may happen. Further discussion to improve structural safety is applied for an existing 5 MW flange joint. Through parametric studies, the major factors influencing ultimate strength are identified. The results show that the aspect ratio plays an important role in increasing the structural safety of the flange joints, while the width of the flange segment weakens the stiffness of the flange-to-shell junction. The findings in this study are expected to provide a useful reference for designing the L-type flange joints in practical engineering fields.
Earthquake Algorithm-Based Voltage Referenced MPPT Implementation through a Standardized Validation Frame
Authors: Ortiz Alexandro , Mendez Efrain , Macias Israel , Molina Arturo
Published: November 2022

This paper presents a new direct maximum power point tracking (MPPT) with a reference voltage (Vref) based on the metaheuristic earthquake algorithm (EA) where the optimization variable is the Vref for hard-switching converters. The efficiency and performance of EA-MPPT-Vref is compared with the perturb-and-observe (P&O) counterpart technique due to the fact that it is widely used for commercial products. Static and dynamic responses for both MPPT strategies are evaluated, which correspond to steady-state oscillations when they are near the maximum power point (MPP), and the tracking-speed, respectively. The efficiency was evaluated with the EN 50530 standard. The results show that the new MPPT proposed is a competitive method using the EA to obtain the optimal voltage reference. From static results, EA-MPPT VP presented a better efficiency of 5.13% and 3.23% for European and California energy commission (CEC) efficiency, respectively. Whereas, from dynamic results, MPPT-Vref techniques presented an efficiency from 95.13% to 99.91%, and 99.01% to 99.91% of the total power of the PV system for P&O and EA strategies, respectively.
Study on Unstable Combustion Characteristics of Model Combustor with Different Swirler Schemes
Authors: Hao Jiangang , Ding Yang , Yang Chen , Wang Xuhuai , Zhang Xiang , Liu Yong , Jin Feng
Published: November 2022

In this paper, the effect of the swirler scheme on combustion instability is studied. Through the proper orthogonal decomposition (POD) of flame images, Abel inverse transform and other methods, the influence of swirl intensity on the characteristic frequency of combustion instability was emphatically studied. Based on the low order thermoacoustic network (LOTAN) of the combustor, the flame transfer function (FTF) under different swirl schemes was obtained by the optimization method. The experimental results show that the stable combustion equivalence ratio boundary of the system decreases monotonously with the decrease in swirl intensity, while the characteristic frequency of unstable combustion is not monotonous with the swirl intensity (the oscillating frequency of swirler A with the largest swirl intensity is approximately 319 Hz, swirler B is approximately 280 Hz, swirler C with the smallest swirl intensity is approximately 290 Hz). The optimization results of FTF can easily introduce this non monotonic phenomenon. The swirl intensity mainly affects the hysteresis time of the system (the lag time of swirlers A, B and C are 5.98 ms, 6.82 ms and 6.20 ms, respectively), which is mainly caused by affecting the flame structure and convection velocity. At the same time, the FTF obtained by optimization reflects the same trend with the experimental results, and there is no significant difference in value, which proves the rationality of the optimization method. This work emphasizes the importance of FTF for combustion instability analysis.
Neural Inverse Optimal Control of a Regenerative Braking System for Electric Vehicles
Authors: Ruz-Hernandez Jose A. , Djilali Larbi , Ruz Canul Mario Antonio , Boukhnifer Moussa , Sanchez Edgar N.
Published: November 2022

This paper presents the development of a neural inverse optimal control (NIOC) for a regenerative braking system installed in electric vehicles (EVs), which is composed of a main energy system (MES) including a storage system and an auxiliary energy system (AES). This last one is composed of a supercapacitor and a buck–boost converter. The AES aims to recover the energy generated during braking that the MES is incapable of saving and using later during the speed increase. To build up the NIOC, a neural identifier has been trained with an extended Kalman filter (EKF) to estimate the real dynamics of the buck–boost converter. The NIOC is implemented to regulate the voltage and current dynamics in the AES. For testing the drive system of the EV, a DC motor is considered where the speed is controlled using a PID controller to regulate the tracking source in the regenerative braking. Simulation results illustrate the efficiency of the proposed control scheme to track time-varying references of the AES voltage and current dynamics measured at the buck–boost converter and to guarantee the charging and discharging operation modes of the supercapacitor. In addition, it is demonstrated that the proposed control scheme enhances the EV storage system’s efficacy and performance when the regenerative braking system is working. Furthermore, the mean squared error is calculated to prove and compare the proposed control scheme with the mean squared error for a PID controller.
Advanced Coal, Petroleum, and Natural Gas Exploration Technology
Authors: Feng Gan , Xie Hongqiang , Meng Qingxiang , Wu Fei , Li Gan
Published: November 2022

Oil, coal, and natural gas are traditional fossil energy sources and the main components of primary energy consumption globally [...]
Fuel-Water Emulsion as an Alternative Fuel for Gas Turbines in the Context of Combustion Process Properties—A Review
Authors: Niszczota Paweł , Chmielewski Maciej , Gieras Marian
Published: November 2022

Fuel with the addition of water, forming fuel-water emulsions, is a potential way to reduce the emission of pollutants from gas turbines powered by any liquid fuel. This article analyzes the available work on the combustion of fuel-water emulsions in gas turbines. The literature analysis was preceded by a theoretical introduction on fuel-water emulsion, taking into account the factors influencing its micro- and macroscopic properties. The basic features of the agents used to stabilize the emulsion were also discussed and the process of its combustion was described. The analyzed research differed in terms of the test stands on which the experiments were conducted, the fuel constituting the continuous phase of the emulsion, the amount of water contained in the mixture and the method of producing the emulsion. On the basis of the conducted analysis, conclusions were drawn concerning the influence of feeding a gas turbine with a fuel-water emulsion on the emission of nitrogen oxides, carbon monoxide and exhaust smoke. Conclusions were formulated regarding the influence of the water additive to fuel-on-fuel consumption. In addition, the impact of the presence of water on the conversion of nitrogen contained in the fuel to nitrogen oxides was indicated, and areas requiring further research were presented.
Agricultural Biomass-Based Power Generation Potential in Sri Lanka: A Techno-Economic Analysis
Authors: Illankoon W. A. M. A. N. , Milanese Chiara , Girella Alessandro , Rathnasiri Puhulwella G. , Sudesh K. H. M. , Llamas Maria Medina , Collivignarelli Maria Cristina , Sorlini Sabrina
Published: November 2022

Worldwide energy costs have grown in recent years due to the dwindling global fossil fuel resources and the increased reliance on them for global energy production. This is a common scenario in many nations, including Sri Lanka. As a developing country, Sri Lanka should encourage the diversification of its renewable energy supplies using locally available resources. In this regard, Sri Lanka can promote the use of agricultural residues for energy generation. The present work explores the energy potential of the solid waste generated by the rice industry: rice straw (RS) and rice husk (RH). A new approach was developed using statistical data on rice production and paddy cultivation in each district of the island. The obtained data were integrated into a geographic information system (GIS) to provide geo-referenced results. A physico-chemical characterization of the RS and RH was conducted to correlate the properties of raw materials to their potential energy generation. As an energy generation technology, the grate-fired combustion boiler accompanied by steam turbine cycle (GFC/ST) was selected. Our findings show that the total energy capacity using by-products of the rice industry is estimated to be 2129.24 ktoe/year of primary energy, with a capacity of 977 Mwe, producing 5.65 TWh of electricity annually. An economic analysis shows ten districts have a high profit index (PI > 1). The districts with the highest PI values are Anuradhapura, Ampara, Polonnaruwa, and Kurunegala, with annual energy potentials of 286 ktoe, 279 ktoe, 231 ktoe, and 160 ktoe, respectively. This work aims to aid future policy decisions by identifying potential districts in which to develop infrastructure for energy generation using agricultural waste, thus reducing net greenhouse gas emissions (GHG) of Sri Lanka.
Research on Packet Control Strategy of Constant-Frequency Air-Conditioning Demand Response Based on Improved Particle Swarm Optimization Algorithm
Authors: Liu Qian , Fu Guangnu , Ma Gang , He Jun , Li Weikang
Published: November 2022

To better utilize air-conditioning load in terms of demand side response potential and improve precision and speed, a control strategy of traditional temperature-control air conditioning, determining frequency load as the research object, and air conditioning determined with a frequency theory model and the Monte Carlo method, were used to construct a power aggregation model. This was combined with user feedback to study thermal comfort as a lateral load demand response resource to determine the potential demand response of power systems. Based on the state-queuing model, an air-conditioning load grouping control strategy using an improved particle swarm optimization algorithm is proposed which can accurately control the air-conditioning load following the reference load.
Challenges and Opportunities for Integrating RE Systems in Egyptian Building Stocks
Authors: Elshamy Ahmad I. , Elshazly Engy , Oladinrin Olugbenga Timo , Rana Muhammad Qasim , Abd el-Lateef Rasha Said , El-Badry Seif Tarek , Elthakaby Mahmoud , Elbaz Ahmed M. R. , Dewidar Khaled , El-Mahallawi Iman
Published: November 2022

The twentieth century started with engineers’ new concepts and ideas to develop the built environment, with ideas ranging from reducing weight to automated industrialisation, enhancing energy efficiency, etc. However, they failed to predict the negative impact of automation on the environment and its resources. Therefore, future technologies proposed by engineers should consider the adverse effects on nature and the surrounding ecosystem. Using the science of ecology and integrating it into building typology can help avoid unwanted scenarios. Such technologies prioritise the performance of buildings and cities by using simulation tools to explore more ideas for designing and testing their performance. This work explores the obstacles and challenges opposing the plan to successfully supply Egypt with clean, renewable energy that reaches 42% of its total electricity. Furthermore, some solutions are proposed to tackle those barriers, such as installing thermal cooling systems and ball wind turbines in residential buildings.
How Dependent Are European Power Systems and Economies on Natural Gas?—A Macroeconomic Optimization for Security of Electricity Supply
Authors: Kockel Christina , Nolting Lars , Pacco Kevin , Schmitt Carlo , Moser Albert , Praktiknjo Aaron
Published: November 2022

How dependent are European power systems and economies on natural gas? To answer this pressing question, we coupled a simulation model for assessing security of electricity supply and an economic optimization model. With this, we were able to analyze different reduction scenarios of the amount of gas utilized in the power sector. Our results show that reducing the amount of natural gas in the European power sector by up to 30% has a relatively moderate impact on the security of electricity supply. Restrictions of 40% or more result in substantially higher reductions in electricity demand shortfall and are associated with economic costs of more than EUR 77 billion. Furthermore, we demonstrate that a close coordination of gas distribution on a European level would be instrumental in mitigating negative economic consequences. Finally, it can be deduced that a coordinated delay of planned power plant shutdowns could effectively compensate for reduced gas volumes in the electricity sector.
Sequential Design of Decentralized Robust Controllers for Strongly Interconnected Inverter-Based Distributed Generation Systems: A Comparative Study versus Independent Design
Authors: Shojaee Milad , Azizi S. Mohsen
Published: November 2022

Internal oscillations among multiple generation systems in low-voltage stand-alone nanogrids and small-scale microgrids can cause instability in the entire generation system. This issue becomes worse when the coupling strength between the generation systems increases, which is a result of a shorter distance between them and a smaller reactance to resistance ratio. Previous approaches, which were based on the independent control design and considered the coupling effect as disturbances, may fail to tackle this issue when the two generation systems become strongly coupled. Therefore, in this paper a novel method is proposed to handle this coupling effect by designing robust decentralized controllers in a sequential manner to address the problem of voltage and frequency control in a nanogrid. This proposed sequential design is a general technique that is applicable to multiple inverter-based generation systems in a nanogrid or small-scale microgrid. For the ease of demonstration, in this paper the case of two interconnected inverters with LC output filters is studied. Two robust decentralized controllers are designed for the two inverter systems by using the μ-synthesis technique. The sequential design takes into account the interconnection line between the two inverters. Moreover, the controllers are designed to be robust against all the parameter variations in the system including the LC filter and interconnection line parameters. The simulation results demonstrate the superior performance of the proposed controller over the independently-designed controllers for the case of two generation systems that are highly coupled due to the short distance between them. Moreover, the proposed controller is shown to be robust against the LC filter and interconnection line parameter uncertainties as compared to the sequentially-designed linear quadratic Gaussian controllers.
Privacy-Preserving Charging Coordination Scheme for Smart Power Grids Using a Blockchain
Authors: Habbak Hany , Baza Mohamed , Mahmoud Mohamed M. E. A. , Metwally Khaled , Mattar Ahmed , Salama Gouda I.
Published: November 2022

With the rapid emergence of smart grids, charging coordination is considered the intrinsic actor that merges energy storage units (ESUs) into the grid in addition to its substantial role in boosting the resiliency and efficiency of the grid. However, it suffers from several challenges beginning with dependency on the energy service provider (ESP) as a single entity to manage the charging process, which makes the grid susceptible to several types of attacks such as a single point of failure or a denial-of-service attack (DoS). In addition, to schedule charging, the ESUs should submit charging requests including time to complete charging (TCC) and battery state of charge (SoC), which may disclose serious information relevant to the consumers. The analysis of this data could reveal the daily activities of those consumers. In this paper, we propose a privacy-preservation charging coordination scheme using a blockchain. The blockchain achieves decentralization and transparency to defeat the security issues related to centralized architectures. The privacy preservation will be fulfilled using a verifiable aggregation mechanism integrated with an aggregated signing technique to identify the untrusted aggregator and assure the data source and the identity of the sender. Security and performance evaluations are performed, including off-chain and on-chain experiments and simulations, to assess the security and efficiency of the scheme.
Sustainable Transport: A State-of-the-Art Literature Review
Authors: Roman Monika
Published: November 2022

The transport sector plays an important role in society at large. This article aimed to provide a state-of-the-art literature review in the area of sustainable transport. Data for the analysis were collected from the Web of Science database from 2000 to 2022. A total of 1238 bibliometric records of publications were collected. Quantitative and qualitative analyses were undertaken in the article. The analysis results showed five main research areas: 1—sustainable urban/public transport and mobility; 2—transport emissions and fuels; 3—sustainable supply chain/logistics management models; 4—performance and metrics in sustainable transport; and 5—future and policy. The limitations of the research carried out, which mainly concern the methodological section, should also be borne in mind. These include the selected publication base and search criteria, such as the year or language of publication.
A Survey of the Quasi-3D Modeling of Wind Turbine Icing
Authors: Martini Fahed , Ilinca Adrian , Rizk Patrick , Ibrahim Hussein , Issa Mohamad
Published: November 2022

Wind turbine icing has been the subject of intensive research over the past two decades, primarily focusing on applying computational fluid dynamics (CFD) to 2D airfoil simulations for parametric analysis. As a result of blades’ airfoils deformation caused by icing, wind turbines experience a considerable decrease in aerodynamic performance resulting in a substantial loss of productivity. Due to the phenomenon’s complexity and high computational costs, a fully 3D simulation of the entire iced-up rotating turbine becomes infeasible, especially when dealing with several scenarios under various operating and weather conditions. The Quasi-3D steady-state simulation is a practical alternative method to assess power loss resulting from ice accretion on wind turbine blades. To some extent, this approach has been employed in several published studies showing a capability to estimate performance degradation throughout the generation of power curves for both clean and iced wind turbines. In this paper, applying the Quasi-3D simulation method on wind turbine icing was subject to a survey and in-depth analysis based on a comprehensive literature review. The review examines the results of the vast majority of recently published studies that have addressed this approach, summarizing the findings and bringing together research in this area to conclude with clear facts and details that enhance research on the estimation of wind turbine annual power production loss due to icing.
Research Progress of SPH Simulations for Complex Multiphase Flows in Ocean Engineering
Authors: Guan Xiang-Shan , Sun Peng-Nan , Lyu Hong-Guan , Liu Nian-Nian , Peng Yu-Xiang , Huang Xiao-Ting , Xu Yang
Published: November 2022

Complex multiphase flow problems in ocean engineering have long been challenging topics. Problems such as large deformations at interfaces, multi-media interfaces, and multiple physical processes are difficult to simulate. Mesh-based algorithms could have limitations in dealing with multiphase interface capture and large interface deformations. On the contrary, the Smoothed Particle Hydrodynamics (SPH) method, as a Lagrangian meshless particle method, has some merit and flexibility in capturing multiphase interfaces and dealing with large boundary deformations. In recent years, with the improvement of SPH theory and numerical models, the SPH method has made significant advances and breakthroughs in terms of theoretical completeness and computational stability, which starts to be widely used in ocean engineering problems, including multiphase flows under atmospheric pressure, high-pressure multiphase flows, phase-change multiphase flows, granular multiphase flows and so on. In this paper, we review the progress of SPH theory and models in multiphase flow simulations, discussing the problems and challenges faced by the method, prospecting to future research works, and aiming to provide a reference for subsequent research.
A New Approach to Risk Management in the Power Industry Based on Systems Theory
Authors: Gołȩbiewski Dariusz , Barszcz Tomasz , Skrodzka Wioletta , Wojnicki Igor , Bielecki Andrzej
Published: November 2022

Contemporary risk management is based on statistical analysis. Such an approach has a few crucial disadvantages. First of all, it has limited applicability to new technological solutions. In this paper, a new idea for risk evaluation and management is put forward. The proposed approach is based on the autonomous systems theory. The theoretical foundation of the proposed idea is described and its prospective applications are discussed. The proposed measures of risk are based on the idea of the controllability of the system—the greater the level of controllability, the lower the risk. Various aspects of controllability are analyzed—economic, technological, and industrial. For each aspect of controllability, the problem of defining adequate measures for the level of risk is discussed. The proposed approach allows the risk assessor to analyze the system deeply. As a consequence, the analyst can assess the risk based not only on a posteriori statistics but also on an analysis of the crucial properties of the system. This allows the investigator to predict a priori possibilities of critical events. The proposed methodology is applied to the power industry.
Pretreatment in Vortex Layer Apparatus Boosts Dark Fermentative Hydrogen Production from Cheese Whey
Authors: Mikheeva Elza R. , Katraeva Inna V. , Kovalev Andrey A. , Biryuchkova Polina D. , Zhuravleva Elena A. , Vishnyakova Anastasia V. , Litti Yuriy V.
Published: November 2022

Dark fermentation (DF) is a promising process for mitigating environmental pollution and producing “green” H2. However, wider implementation and scaling of this technology is hampered by insufficient process efficiency. In this work, for the first time, the effect of innovative pretreatment of cheese whey (CW) in a vortex layer apparatus (VLA) on characteristics and DF of CW was studied. Pretreatment in VLA resulted in a heating of the CW, slight increase in pH, volatile fatty acids, iron, and reduction in fat, sugar, and chemical oxygen demand (COD). The biochemical hydrogen potential test and analysis of H2 production kinetics confirmed the significant potential of using VLA in enhancement of dark fermentative H2 production. The maximum potential H2 yield (202.4 mL H2/g COD or 3.4 mol H2/mol hexose) was obtained after pretreatment in VLA for 45 s and was 45.8% higher than the control. The maximum H2 production rate after 5 and 45 s of pretreatment was 256.5 and 237.2 mL H2/g COD/d, respectively, which is 8.06 and 7.46 times higher than in the control. The lag phase was more than halved as a function of the pretreatment time. The pretreatment time positively correlated with the total final concentration of Fe2+ and Fe3+ and negatively with the lag phase, indicating a positive effect of pretreatment in VLA on the start of H2 production.
Maximizing Nitrogen Removal and Lipid Production by Microalgae under Mixotrophic Growth Using Response Surface Methodology: Towards Enhanced Biodiesel Production
Authors: Abomohra Abdelfatah , Li Mei , Faisal Shah , Li Li , Elsayed Mahdy
Published: November 2022

The present study aimed to optimize synthetic wastewater composition as a mixotrophic medium for enhanced growth and lipid accumulation coupled with high nitrogen removal by the green microalga Chlorella sp. Individual effects of the three main independent variables (nitrate concentration, seawater ratio, and glycerol supplementation) were tested initially, then response surface methodology (RSM) was subsequently performed to explore the optimum combined conditions. The highest lipid productivity of 37.60 mg/L day was recorded at 25% seawater. Glycerol supplementation enhanced both lipid content and biomass production, which resulted in the highest recorded lipid productivity of 42.61 mg/L day at 4 g/L glycerol. Central composite design followed by numerical optimization was further applied which suggested NaNO3 concentration at 101.5 mg/L, seawater ration of 23.8%, and glycerol supplementation of 0.25 g/L as the optimum conditions for dual maximum lipid productivity and nitrogen removal of 46.9 mg/L day and 98.0%, respectively. Under the optimized conditions, dry weight and lipid content increased by 31.9% and 20.3%, respectively, over the control, which resulted in increase in lipid productivity by 71.5%. In addition, optimization process resulted in pronounced changes in fatty acid proportions where saturated fatty acids increased by 7.4% in the optimized culture with simultaneous reduction of polyunsaturated fatty acids. The estimated biodiesel characteristics calculated from the fatty acid methyl ester (FAMEs) profile showed agreement with the international standards, while optimized cultures showed an 8.5% lower degree of unsaturation, which resulted in higher cetane numbers and lower iodine values. This study provides economical approach for optimization and efficient nutrient recycling through cultivation of Chlorella sp. for further enhanced biodiesel production.
Pilot-Scale Production of the Natural Colorant Laetiporic Acid, Its Stability and Potential Applications
Authors: Bergmann Pia , Frank Christina , Reinhardt Olena , Takenberg Meike , Werner Anett , Berger Ralf G. , Ersoy Franziska , Zschätzsch Marlen
Published: November 2022

Laetiporus sulphureus, a wood-decaying basidiomycete, produces yellow-orange pigments in fruiting bodies and, as was recently shown, in submerged cultivated mycelia. Out of four strains, the most potent laetiporic acid producer was identified and its yield compared in different media. The complex Moser b medium was replaced by potato dextrose broth, achieving higher yields at a lower cost. Cultivation was then scaled up from shake flask to a 7 L stirred tank bioreactor. Optimization of parameters led to increased product concentrations up to 1 g L−1, the highest yield reported so far. An in situ product recovery strategy with a biphasic system was established, increasing the yield by 19% on the shake flask scale. A crude ethanolic extract of the biomass was examined for color stability and application trials. In contrast to what has been suggested in the past, the pigment showed limited long-term stability to oxygen and light, but was stable under storage in the dark at 4 °C under nitrogen. The orange extract was successfully incorporated into different matrices like foods, cosmetics and textiles. Laetiporic acid can potentially replace petrochemical based synthetic dyes, and can thus support the development of a circular bioeconomy.
Research Progress on the Effect of Autolysis to Bacillus subtilis Fermentation Bioprocess
Authors: Ren Kexin , Wang Qiang , Hu Mengkai , Chen Yan , Xing Rufan , You Jiajia , Xu Meijuan , Zhang Xian , Rao Zhiming
Published: November 2022

Bacillus subtilis is a gram-positive bacterium, a promising microorganism due to its strong extracellular protein secretion ability, non-toxic, and relatively mature industrial fermentation technology. However, cell autolysis during fermentation restricts the industrial application of B. subtilis. With the fast advancement of molecular biology and genetic engineering technology, various advanced procedures and gene editing tools have been used to successfully construct autolysis-resistant B. subtilis chassis cells to manufacture various biological products. This paper first analyses the causes of autolysis in B. subtilis from a mechanistic perspective and outlines various strategies to address autolysis in B. subtilis. Finally, potential strategies for solving the autolysis problem of B. subtilis are foreseen.
Spatial and Temporal Distribution Characteristics of Active Fires in China Using Remotely Sensed Data
Authors: Pan Jinghu , Wu Xueting , Zhou Lu , Wei Shimei
Published: November 2022

Based on the FIRMS MODIS active fire location data in the Chinese mainland from 2001 to 2018, the GIS fishing net (1 km × 1 km) was used to analyze the spatiotemporal distribution characteristics of active fire occurrence probability and intensity, and a GWLR fire risk assessment model was established to explore its influencing factors. The results show that active fires in the Chinese mainland are mainly low intensity. They are mainly distributed in the area where the annual average temperature is 14–19 °C, the precipitation is 400–800 mm, the surface temperature is 15–20 °C, the altitude is 1000–3000 m, the slope is <15°, and the NDVI value is >0.6. The GWLR fire risk assessment model was constructed to divide mainland China into five fire risk zones. NDVI, temperature, elevation, and slope have significant spatial effects on the occurrence of active fires in the Chinese mainland. Eight fire risk influencing factor areas were divided by calculation, and differentiated fire prevention suggestions are put forward.
An Experimental Investigation of the Influence of Flow and Pipe Diameter on the Fire Extinguishing Efficiency of Nitrogen Injection in a Narrow Confined Underground Space
Authors: Zhang Guowei , Guo Dong , Li Bin , Zhang Zhiwei , Yuan Diping
Published: November 2022

In this study, an underground pipe gallery was taken as the research subject to explore the influence of nitrogen injection flow rate and pipe diameter on the fire extinguishing efficiency in an underground narrow confined space. A liquid nitrogen fire extinguishing test system for the underground narrow confined space was built. The fire extinguishing time, flame height, temperature, and oxygen concentration under different conditions were recorded by liquid nitrogen fire extinguishing tests, and the variations in the characteristics of these data were analyzed. Furthermore, the fire suppression factor, cooling factor, and asphyxiation factor were introduced to quantify the influence of the nitrogen flow rate and pipe diameter on extinguishing efficiency. According to the results, the fire was effectively extinguished by liquid nitrogen in the underground confined space through asphyxiation as the main fire extinguishing mechanism, and the extinguishing time was about 95.5% less than that in the self-extinguishing test. Although the fire suppression efficiency is positively related to the nitrogen injection flow, the asphyxiation efficiency can be reduced when the flow rate is excessive or too weak. Additionally, the asphyxiation factor and fire suppression factor are highly sensitive to the injection pipe diameter. Therefore, a valuable reference is provided in this study for promoting the future engineering application of liquid nitrogen fire extinguishment.
Effects of Short-Term Salinity Stress on Ions, Free Amino Acids, Na+/K+-ATPase Activity, and Gill Histology in the Threatened Freshwater Shellfish Solenaia oleivora
Authors: Zhang Ting , Yao Jingting , Xu Dongpo , Lv Guohua , Wen Haibo
Published: November 2022

Salinity is an important ecological factor affecting the osmolality of aquatic animals. Solenaia oleivora is an endemic and economically important freshwater shellfish in China. However, its osmotic response and osmoregulatory mechanisms under high salinity stress are still unclear. In this study, S. oleivora was exposed to saline water (salinity: 2.2‰) for 3 h, 6 h, 12 h, 24 h, and 48 h, and then the changes in osmolality, ion concentrations, free amino acid (FAA) content, Na+/K+-ATPase (NKA) activity, and gill histology were analyzed. The hemolymph osmolality increased from 3 h after salinity stress and stabilized between 24–48 h. Na+ in the hemolymph increased from 24 h after salinity stress, and Cl− increased from 3 h. The content of total FAAs in the hemolymph increased after salinity stress. The content of alanine, glycine, glutamine, proline, and other FAAs increased after salinity stress. NKA activity in the gill, hepatopancreases, adductor muscle, and axe foot decreased during 3–48 h of salinity stress. The gill filament space increased and the number of gill cilia decreased after salinity stress. Principal component analysis (PCA) showed that the first two principal components (PC1 and PC2) cumulatively explained 77.6% of the total variation. The NKA activity was positively associated with PC1, while the ion concentration and most FAAs were negatively associated with PC1. Thus, these results indicated that S. oleivora is an osmoconformer, and inorganic ions, FAA, NKA, and gill structure changes play an important role in its osmoregulation.
Genomic Analysis of the Proteasome Subunit Gene Family and Their Response to High Density and Saline-Alkali Stresses in Grass Carp
Authors: Hu Guo , Shu Yongjun , Luan Peixian , Zhang Tianxiang , Chen Feng , Zheng Xianhu
Published: November 2022

The proteasome is a highly conserved polycatalytic enzyme that is required for cellular processes and is widely present in the nucleus and cytoplasm of archaea, as well as all eukaryotes. A total of 22 members of the proteasome subunit (CiPS) gene family were identified and characterized by scanning the grass carp (Ctenopharyngodon idella) genome. These genes were classified into two subfamilies, CiPSA and CiPSB, based on phylogenetic analysis, which was consistent with the results from other species. We examined the response of this gene family to high density and saline-alkali stresses in aquaculture using publicly available transcriptome data resources. In grass carp, CiPS member transcripts were detected in all tested tissues, with the highest expression level in the head kidney and the lowest in the liver. According to transcriptome-based expression analysis, CiPS genes play a role in response to environmental stresses in grass carp, mainly in the form of negative regulation. Interestingly, a cluster of members belonging to the CiPSB subfamily on a 15 kb region on chromosome segment CI01000319, including CiPSB8, 9, 9b, and 10, showed marked responses to high density and saline-alkali stress. It appears that CiPS genes confer stress tolerance through the regulation of common genes, as well as specific genes. In summary, our genome-wide characterization, evolutionary, and transcriptomic analysis of CiPS genes in grass carp provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in aquaculture.
Costimulatory Molecules CD80/86 Trigger Non-Specific Cytotoxic Cell of Nile tilapia (Oreochromis niloticus) to Kill CIK Cells
Authors: Huang Yu , Chen Zhengsi , Xie Ruitao , Amoah Kwaku , Wang Bei , Cai Jia , Lu Yishan , Jian Jichang
Published: November 2022

The teleost non-specific cytotoxic cell (NCC), as the evolutionary precursors of NK cells, is an important cytotoxic cell population in the innate immune system of teleost. We have recently realized that costimulatory CD80/86 have conservation in structural and interactional features with its ligand CD28 in Nile tilapia (Oreochromis niloticus). However, the ability of CD80/86 to regulate NCC activity has not been fully investigated. In the present study, we first obtained the recombinant fusion CD80/86 protein from O. niloticus (rOn-CD80/86). Then, NCC incubation with rOn-CD80/86 resulted in a significant production of NCC effector cytokines, including tumor necrosis factor-alpha, cellular apoptosis susceptibility and NK-lysin. Furthermore, NCC treatment with rOn-CD80/86 could significantly improve the ability to kill kidney cells of Grass carp (CIK) and up-regulate the activities of caspase-1 and caspase-3 in CIKs. The yeast, two-hybrid assay showed that On-CD80/86 cannot directly interact with non-specific cytotoxic cell receptor protein-1 of O. niloticus (On-NCCRP-1). The single-cell RNA-Seq data of Nile tilapia head kidney lymphocytes analysis found On-CD28 did not exhibit expression on NCCs subsets. The above results suggest that costimulatory molecules On-CD80/86 is independent of On-NCCRP-1 and On-CD28 receptor in modulating NCC killing activity in vitro of Nile tilapia. The results also provide more insights into the mechanism of NCC activity regulation.
Mitochondrial Metabolism Characterization of Four Different Fish Cell Lines
Authors: Espinosa-Ruiz Cristóbal , Mayor-Lafuente Javier , Esteban M. Ángeles
Published: November 2022

Mitochondria are a crucial cellular organelle that organizes a wide range of biological processes, from energy production and calcium homeostasis to cell proliferation, differentiation, and death as well as inflammation. Mitochondria also support immune cell phenotypes and function. The aim of this communication is to evaluate the mitochondrial status and plasticity of four fish cell lines: SAF-1 (derived from gilthead sea bream skin), DLB-1 (derived from European sea bass brain), FuB-1 (established from mummichog brain), and PLHC-1 (a topminnow hepatocellular carcinoma). A mitochondrial stress assay was performed to compare the bioenergetic capabilities of these four fish cell lines as well as the importance of choosing the correct cell line when performing different in vitro studies.
Polyculture Affects the Growth, Antioxidant Status, Nutrient Content, and Flavor of Chinese Mitten Crabs (Eriocheir sinensis) and Largemouth Bass (Micropterus salmoides)
Authors: Che Silu , Li Shiheng , Li Quanjie , Sun Yi , Zheng Zhaowei , Nie Zhijuan , Tang Zhonglin , Wang Peipei , Gao Jiancao , Xu Gangchun
Published: November 2022

Chinese mitten crabs (Eriocheir sinensis) and largemouth bass (Micropterus salmoides) are popular with consumers in China. In recent years, the polyculture of these two species has received more attention, but little is known about how their interactions affect their commercially important traits. In this study, we set up an E. sinensis monoculture group (EM), a M. salmoides monoculture group (MM), and a polyculture group containing both species (EP) and compared the growth parameters, antioxidant statuses, nutritional compositions, and flavor qualities of crabs and fish between the different culture modes. Growth parameters in male crabs and largemouth bass were significantly higher in the EP group than in the EM and MM groups, respectively. Crabs in the EM and EP groups did not differ significantly in malondialdehyde content or glutathione peroxidase activity, regardless of the sampling time, which suggests that crabs in these groups had similar antioxidant and immunity capacities. Compared to the MM group, the activities of superoxide dismutase and catalase of largemouth bass in the EP group were higher, indicating the superior antioxidant capacity of fish in the polyculture mode. Alkaline phosphatase and acid phosphatase activities of both crabs and largemouth bass fluctuated with time in all groups, indicating their important roles in maintaining the health of these cultured species. The amino acid and fatty acid contents of edible tissues were similar between the EM and EP groups and the MM and EP groups, suggesting comparable flavor and quality of edible tissues in crabs and largemouth bass between culture modes. This study provides theoretical support for the polyculture of Chinese mitten crabs and largemouth bass.
Bubble Growth in Supersaturated Liquids
Authors: Maloth Raj Kumar Nayak , Khayat Roger E. , DeGroot Christopher T.
Published: November 2022

Bubble formation and dissolution have a wide range of industrial applications, from the production of beverages to foam manufacturing processes. The rate at which the bubble expands or contracts has a significant effect on these processes. In the current work, the hydrodynamics of an isolated bubble expanding due to mass transfer in a pool of supersaturated gas–liquid solution is investigated. The complete scalar transportation equation (advection–diffusion) is solved numerically. It is observed that the present model accurately predicted bubble growth when compared with existing approximated models and experiments. The effect of gas–liquid solution parameters such as inertia, viscosity, surface tension, diffusion coefficient, system pressure, and solubility of the gas has been investigated. It is found that the surface tension and inertia have a very minimal effect during the bubble expansion. However, it is observed that the viscosity, system pressure, diffusion, and solubility have a considerable effect on bubble growth.
Co-Pigmentation Mechanism and Thermal Reaction Kinetics of Mulberry Anthocyanins with Different Phenolic Acids
Authors: Chen Xiangyue , Gao Qunyu , Liao Sentai , Zou Yuxiao , Yan Jiangang , Li Qian
Published: November 2022

Applying the intermolecular co-pigmentation to improve the stability of mulberry anthocyanins is an important co-pigment method. Seven co-pigments, ferulic acid (FA), caffeic acid (CA), p-hydroxybenzoic acid (HBA), protocatechuic acid (PA), gallic acid (GA), vanillic acid (VA) and vanillin (VN) were selected to investigate mulberry anthocyanin co-pigmentation thermal reaction kinetics. The strongest co-pigment reactions were observed for FA at a molar ratio of 1:20, pH 3.5 and 20 °C, with the highest hyperchromic effects (52.94%), equilibrium constant (K) values (3.51) and negative values of Gibbs free energy (ΔG°) (−3.06 KJ/mol). Co-pigments that contained more free hydroxyl groups facilitated the co-pigmentation, and methyl contributed more to color enhancement, with respect to the hydrogen group. Ultra Performance Liquid Chromatography-Quadrupole-Time Of Flight-Mass/Mass Spectrometry (UPLC-Q-TOF-MS/MS) results indicated that FA and CA formed different anthocyanin derivatives with mulberry anthocyanin. The Fourier Transform Infrared Spectroscopy (FTIR) and molecular docking confirmed that hydrogen bonding, π–π stacking and hydrophobic interaction were formed between anthocyanins and three prevalent co-pigments (FA, CA and VA). CA and C3G could form four hydrogen bonds and two π–π stackings; this was the most stable system among three phenolic acid–C3G complexes. Due to the functional effect of phenolic acids, the addition of FA and CA not only enhanced the stability and color intensity of mulberry anthocyanins but also the functionality of the processing product.