bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Effect of Ultra-fine Limestone Powder on the Resistance of Cement-slag Powder System to Chloride Ion Permeability
Authors: Gao Xin 
Published: March 2024

Abstract
The effect of different limestone powder fineness on the chloride ion migration coefficient of the cement paste was tested using the Rapid Chloride Migration (RCM) method. The changes in the phase composition and pore structure of the paste were studied using hydration kinetics analysis, XRD and pore structure analysis. The results showed that before the chloride ion erosion, the limestone powder mainly exhibited filling effect, microcrystalline nucleation effect, and chemical activity effect. It reacted with the hydration products of cement to form calcium aluminate carbonate, which improved the strength of the hardened paste. After chloride ion erosion, the diffraction peak of calcium aluminate carbonate weakened, and Friedel’s salt was formed. With the increase of the specific surface area of limestone powder, the chemical activity of the powder became more obvious, and the generation of Friedel’s salt increased, leading to stronger resistance to chloride ion penetration. Limestone powder can reduce the porosity of the hardened paste and optimize the pore structure. When the particle size of the powder increased from 800 to 5000 mesh, the total porosity of the hardened paste decreased from 20.7% to 14.7%, and the most probable pore size decreased from 450nm to 75nm. Limestone powder with a particle size larger than 1500 mesh can fully exert its activity and play a role in solidifying chloride ions, thus improving the resistance to chloride ion penetration of limestone powder cement-based materials.
Analysis of the Temporal and Spatial Development of Cold Waves in Fujian Province over the Last 58 Years
Authors: Wang Tiantian , Jin Shaofei , Wang Ku 
Published: March 2024

Abstract
The escalation in the risk of extreme weather events due to climate system warming has caused a distinct alteration in the frequency and intensity of cold waves in China. Moreover, these changes exhibit distinct regional variations in their altering characteristics. Using daily temperature data from 70 weather stations in Fujian Province of China from 1961 to 2018, this study looks at how cold waves move through the province and how they change over time. It does this by combining linear regression trend, spatial interpolation, and spatial autocorrelation analyses. The findings indicate that the occurrence frequency of cold waves in the designated study area is notably higher in the western and northern regions, while it is comparatively lower in the eastern coastal cities. Furthermore, there is an overall downward trend in the frequency of cold waves, with a declining frequency from 1961 to 2000, followed by a significant increase in frequency after 2000. Furthermore, the number of cold waves in the study area increased significantly after 2010.
Pore-scale Simulation of Two-phase Flow in Foamed Porous Materials
Authors: Liang Yaxuan , Wang Ping , Zhang Xuan , Dou Haoyuan 
Published: March 2024

Abstract
This paper establishes a pore cell model of foamed silicon carbide material based on a tetradecahedron structure, and uses FLUENT software to numerically study the flow rate and pressure drop changes in the porous structure at different flow rates and the gas-liquid two-phase flow state of the channel. The research results show that the porous skeleton structure has a great influence on the velocity and pressure distribution in the calculation domain; the inlet flow velocity has a certain impact on the gas-liquid mixing zone and gas-liquid interface area in two-phase flow. The application of tetradecahedral porous media increases the thickness of the gas-liquid mixing zone and the phase interface area are increased, with a maximum increase of 11.5%, thus promoting gas-liquid heat and mass transfer.
Application Practice for Low Environmental Impact Deep Acidizing Process to Improve Injection Capacity of Water Injection Wells
Authors: Deng Xiaoguo , Yan Yu , Fu Jie , Li Heng , Yang Yang , Cai Qingqin , Cao Xiaomei , Dou Tongwei , Zhao Junfeng , Jing Haiquan 
Published: March 2024

Abstract
There are problems of high injection pressure and water injection difficulties in some injection wells among more than thirty wells that have been injected in H oilfield, and the overall water injection is insufficient. This paper analyzes the reasons for the injection problem from the perspective of block characteristics: for the decline in injection capacity due to reservoir pore blockage caused by clay expansion and contamination by injected impurities, it is proposed to apply a low environmental impact deep acidification system to improve the injection capacity of water wells.
Research Progress of Microplastic Pollution Status and Risk Assessment of Typical Rivers in China
Authors: Zhang Jie , Hong Lei , Wu Ke , Wang Qun , Li Mengmeng , Li Xu , Jin Jie 
Published: March 2024

Abstract
Microplastics (MPs) have received a lot of attention since they were recognized as an emerging pollutant. Rivers transport 80 % of the land’s MPs to the oceans. With so many rivers in China, the problem of MPs pollution cannot be ignored. This paper collects data related to MPs in typical rivers in China, summarizes the sources of river MPs, and analyses the status of river MPs pollution and risk evaluation. The results show that riverine MPs mainly originate from sewage treatment plants, surface runoff, atmospheric deposition and plastic breakage. MPs abundance is closely related to population density, with urban rivers having higher MPs abundance than other regions. MPs less than 1 mm in size account for more than 60 % of most rivers. At present, the risk assessment of river MPs is mainly based on three methods, namely, the ecological risk index (PHI), the pollution load index (PLI) and the potential ecological risk index (PERI), and the results of the assessment are mostly low risk. There are differences in the results of the assessment models, which need to be applied jointly with each other for continuous improvement.
Simulation of Fountain Flow based on Molecular Dynamics Method
Authors: Chen Tengfei , Pu Kejin , Zhang Xiaoliang , Zhao Zhongshuai , Guo Chao , Yan Baoshan , Wang Tingjun 
Published: March 2024

Abstract
In this paper, numerical simulations of the fountain effect on the flow front of polymer dilute solutions are carried out based on molecular dynamics principles and the FENE dumbbell model. The Euler method is used to solve the constitutive equations of the mechanical model for the simple shear flow field and the dislocation equations of the dumbbell molecules, and subsequently obtain the tracer flow lines and the dumbbell distribution of the flow front. The results are used to calculate the stress field, analyze the rheological evolution law, study the effect of temperature and shear rate and other parameters on the model and analyze the effectiveness of the FENE dumbbell molecular model for the fountain effect. The study shows that due to the fountain effect the dumbbell molecules stretch more with increasing shear rate, the polymer stress at the flow front will show a complex change of stress overshoot and then stabilize, and the dumbbell molecules are oriented along the fountain flow line.
Aerodynamic Investigation of Propulsion Integration for a Low Noise Hybrid Wing-Body with Podded UHBR Turbofan Engines
Authors: Keller Dennis 
Published: March 2024

Abstract
The presented work examines the aerodynamic challenges of podded ultra high-bypass engines installed on a short/mid range low noise hybrid wing body configuration. After assessing the initial engine integration design, sensitivity studies regarding the impact of the freestream Mach number, engine position, and the engine incidence angle on the interference drag are discussed. Then, shape modifications of the nacelle and the center-body based on 2D RANS optimizations are presented. The results indicate that in order to reduce the initially massive interference drag, the overall aircraft design either has to allow for a modified engine position or for reshaping of the center-body’s upper surface. With the latter, an overall drag reduction of –44 % was achieved.
Electric flight operations for interisland mobility
Authors: Donckers S , Stamoulis K P , Apostolidis A 
Published: March 2024

Abstract
Several studies have shown that flying electric between the so-called ABC-islands in the Caribbean (i.e., Aruba, Bonaire and Curaçao) is feasible with the upcoming first generation of battery-electric aircraft. This paper presents a real-world case study that deals with the technical and operational characteristics of electric flight in that region. With that purpose, the Aruba Airport Authority (AAA) commissioned this investigation, which involved numerous local stakeholders, such as airlines, energy providers and navigation services. This study involves two commuter electric aircraft under development, aiming to investigate how they fit in the current operational scheme of three local airlines and three conventional aircraft types in terms of technology, capacity, schedule, performance, CO2 emissions and fuel costs. Conclusions indicate that a transition to batter-electric aircraft is feasible with regards to the aforementioned criteria and with the current technology and energy density of batteries.
Reducing Environmental Impact of Jet Engines by Hydrogen Co-combustion
Authors: Przysowa Radoslaw , Grundas Dariusz , Gawron Bartosz , Zieliński Konrad 
Published: March 2024

Abstract
Due to the need to mitigate global warming, there is a growing interest in alternative fuels for various means of transport, including aviation gas-turbine engines. The work aimed to check the impact of hydrogen co-combustion on the performance and emissions of aircraft engines. Zero-dimensional models of JetCat P140 RXI and DGEN 380 engines developed in the GSP (Gas Turbine Simulation Program) program were used in the research. Combustion calculations in GSP are based on the real gas model and NASA Chemical Equilibrium Applications (CEA) equations. The performance of the engines fueled by Jet A-1 and blends containing hydrogen or methane were calculated. The simulations were performed at the design point on the ground, and then in flight for selected altitudes and flight speeds. With an increase in the gas content in the blend, the thrust and temperature behind the turbine slightly increase, and the specific fuel consumption decreases, because hydrogen and methane have a higher calorific value. The performance of JetCat and DGEN 380 engines was calculated for blends of kerosene with methane or hydrogen. This knowledge will be used to convert these engines to gaseous fuels. In terms of fuels and emissions, GSP has limitations related to the set of available chemicals and the zero-dimensional model of the combustor.
An overview of the possibilities, current status, and limitations of battery technologies to electrify aviation
Authors: Suárez María Zamarreño , Moreno Francisco Pérez , Jurado Raquel Delgado-Aguilera , Valdés Rosa María Arnaldo , Comendador Víctor Fernando Gómez 
Published: March 2024

Abstract
One of the main concerns of the aviation industry is the reduction of dependence on fossil fuels, the reduction of emissions, and, ultimately, the development of a more sustainable air transport system. Emerging technologies, new operational concepts, and research will be essential to achieve this. Batteries are one of the emerging technologies that will play a key role in the electrification of aviation in the coming years. To ensure the scalability of this technology, an analysis of its possibilities, current status, and limitations is essential. The aim of this study is to carry out such an analysis, answering five key questions related to this technology: i) what is a battery?, ii) what are the key parameters of batteries?, iii) what are the possibilities of battery technology to electrify aviation?, iv) what are the main challenges to overcome?, and finally, v) how can batteries be classified? The answers to these questions will make it possible to present the state of the art of this technology, and to identify the main challenges to be addressed in its future development.
Energy management of an eVTOL aircraft with optimization based on the Equivalent Consumption Minimization Strategy (ECMS)
Authors: Taghbalout Meryem 
Published: March 2024

Abstract
This article introduces an optimization-based energy management strategy developed and validated for electric vertical take-off and landing (eVTOL) aircraft. The primary objective of this strategy is to minimize hydrogen consumption while accounting for resource constraints, such as the battery and fuel cell, to enhance energy efficiency and sustainability while adhering to performance and safety requirements. The eVTOL employed in this research is an essential component of our “Viable” research project, featuring a hybrid propulsion system that combines batteries and fuel cells.
To accomplish this, mathematical and computational techniques were employed using the equivalent consumption minimization strategy method to determine the optimal operational parameters for the eVTOL aircraft, considering the available energy resources. These techniques were implemented for the first time in MATLAB, enabling simulations of the aircraft’s performance under various conditions. The results demonstrate the efficacy of the energy management strategy in significantly reducing hydrogen consumption while maintaining optimal performance and safety. Graphs and comparative analyses are presented to highlight the evolution of hydrogen consumption compared to different parameters and to compare the approach with alternative methods.
Furthermore, the article explores an alternative solution that offers related results and performance as MATLAB, utilizing the open-source software OpenModelica (OM). Energy management experiments using ECMS were conducted on OM, yielding highly satisfactory outcomes in terms of simulation accuracy and cost-effectiveness. The method was also evaluated in simulations of propulsive system resources, developed on OM, validating the results concerning energy distribution, compliance with constraints, and real-time feedback.
In summary, this article presents a comprehensive strategy for effectively managing energy consumption in eVTOL aircraft. By leveraging simulations conducted in MATLAB and OM, the strategy’s effectiveness was assessed, with potential implications for advancing the sustainability of electric eVTOL aircraft.
Kinetic Energy Recovery from a landing aircraft: Evaluating Onboard Energy Solutions
Authors: Camilleri R , Batra A , Bartolo L B , Delavault A 
Published: March 2024

Abstract
This paper compares onboard Energy Storage Solutions (ESSs) for a Kinetic Energy Recovery System (KERS) from a landing aircraft. Energy is stored temporarily and reused so that it enables engine-less taxiing. This paper evaluates the choice of onboard Energy Storage Solutions (ESSs) (flywheels, batteries and supercapacitors) for recovering energy during the landing roll and storing it in the device. A design of an ESS with each of the three technologies was made, using commercially available products. The resulting devices are compared on the basis of weight, charging time, discharging time and complexity in retrofitting to existing systems. Results shows that while batteries have the highest energy density and will have the lowest weight, they are unable to charge/discharge quickly enough to satisfy this application. Conversely, supercapacitors have this ability but their low energy density make them heavy which in turn would offer penalty to the aircraft in flight. Flywheels emerge as the most interesting proposition due to their high energy density and fast charging ability, which satisfy the requirements for application.
A Versatile Computation Platform applied to Environmental-Impact Assessments at Airport Level in Clean Sky 2
Authors: Weggemans J E , van Eenige M J A 
Published: March 2024

Abstract
The objective of the Clean Sky 2 Technology Evaluator project GREENPORT2050 is to assess the environmental impact up to 2050 at airport level of technologies developed in Clean Sky 2 for fixed-wing aircraft. To not only facilitate computational processes and improve their efficiency, but also to ensure quality and configuration-management tasks are automatically and well taken care of, Royal NLR develops a versatile computation platform for conducting these assessments. This paper provides an overview of the platform’s implementation (adopting modern, widely-accepted and proven technologies) and its key features (especially in relation to the mechanism of defining and integrating models).
Synergy in Future Avionics: An Overview of Multiple Technologies for Small Air Traffic Segment in the COAST project
Authors: Lucky Jakub , Vito Vittorio Di , Beran Jan , Kabrt Tomas , Vaispacher Tomas , Korenciak Lubos , Dobes Michal , Grzybowski Piotr , Masłowski Piotr 
Published: March 2024

Abstract
The paper describes research and development activities under Clean Sky 2 Cost optimized Avionic System (COAST) program. The main goal of this development was to deliver technology enablers at TRL 5 for affordable cockpit and avionics. The target segment for the technology enablers is aircraft with 1 to 19 passengers and small cargo aircraft belonging to CS-23 category. The main aim is to provide overall summer during the whole COAST program development per individual technology. Sections are divided per each technology with their results and overall contribution to the program. The Clean Sky 2 COAST program covered the development of following technologies: Cockpit Architecture SAT avionic system architecture, Flight Management Tactical Separation System (TSS), Advanced Weather Awareness System (AWAS), Flight Reconfiguration System (FRS), Navigation and Surveillance Dual Frequency Multi-Constellation GNSS Receiver (GNSS), Low-cost Integrated Navigation System (NAV), Affordable Integrated Surveillance System (SURV), Platform technologies Compact Computing Platform (CCP), High Integrity Electronics for health monitoring (HIE), Integrated Mission Management System Integrated Mission Management System (IMMS). These technologies were part of several flight test campaigns which took place in the Czech Republic with Evektor company using EV-55 aircraft.
On UAV Terrestrial Connectivity Enhancement through Smart Selective Antennas
Authors: Pagliari Emanuele , Davoli Luca , Cicioni Giordano , Palazzi Valentina , Ferrari Gianluigi 
Published: March 2024

Abstract
Nowadays, Unmanned Aerial Vehicles (UAVs) are widely used in heterogeneous contexts and, thanks to a continuous technological evolution, are going to be used for several applications such as, for example, Beyond Visual Line of Sight (BVLOS) operations. Since in BVLOS flights the UAV and the ground control center may not have a direct visibility with each other, a robust communication system is needed to provide reliable connectivity. Although a cellular (4G/5G) network is the current best candidate to enable BVLOS applications, there are still some limitations to overcome, as 4G (LTE) and 5G (NR) cellular networks are natively designed for terrestrial use. In this paper, we first investigate current cellular communication limitations for UAV-based applications, in particular taking into account both results available in the literature, as well as experimental performance campaigns. Then, a viable solution for mitigating these drawbacks exploiting selective on-board antennas is proposed, whose performance is experimentally investigated with a preliminary prototypical architecture.
On-board drone classification with Deep Learning and System-on-Chip implementation
Authors: Di Cecio G , Manco A , Gigante G 
Published: March 2024

Abstract
In recent years the increasing use of drones has raised significant concerns on safety and make them dramatic threats to security. To address these worries Counter-UAS Systems (CUS) are capturing the interest of research and of industry. Consequently, the development of effective drone detection technologies has become a critical research focus. The proposed work explores the application of edge computing to drone classification. It tunes a Deep Learning model, You Only Look Once (YOLO), and implements it on a Field Programmable Gate Array (FPGA) technology. FPGAs are considered advantageous over conventional processors since they enable parallelism and can be used to create high-speed, low-power, and low-latency circuit designs and so to satisfy the stringent Size, weight and Power (SWaP) requirements of a drone-based implementation. In details, two different YOLO neural networks YOLO v3 and v8 are trained and evaluated on a large data set constructed with drones’ images at various distances. The two models are then implemented on a System-on-Chip (SoC). In order to demonstrate the feasibility of a drone on board image Artificial Intelligence processing, the evaluation assesses the accuracy of classification and the computational performances such as latency.
Reducing Ground Impact Hazards of a Solar UAV Through Modelling and Analysis
Authors: Dalla Vedova M D L , D’Amico F A , De Maria T , Maggiore P , Pitarresi G 
Published: March 2024

Abstract
The research described was conducted by a student team dedicated to finding sustainable and long-endurance systems and outlines an innovative solar panel UAV aircraft solution. Our prototype demonstrated the feasibility of the concept, while the second aircraft, currently in the design phase, aims to improve performance further and allow for extended self-powered flight time. The sustainable approach of our project addresses the growing need to reduce the environmental impact of transportation technologies. The main objective of this study is to address the requirements of the Specific Category - Civil Drones regulation, promulgated by EASA, regarding the risk associated with the impact of the aircraft on the ground in case of an in-flight failure. To address this issue, we conducted an in-depth analysis of possible failure scenarios and their consequences on the safety of the aircraft and people on the ground. Furthermore, the team developed models for risk assessment to evaluate the risk associated with solar panel UAV operation. To mitigate the risk of impact, we considered using a parachute, the effectiveness of which was analysed using a dynamic model implemented in Simulink. The analysis allowed us to evaluate the semi-controlled descent of the aircraft with the parachute attached, providing valuable information to optimize the safety system further. In conclusion, our study significantly contributes to ensuring the safety of our model in flight and on the ground through ground-impact risk management while promoting the development of sustainable and innovative solutions in the aviation field.