bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laser Doppler Vibrometry for detecting survivors in hard-to-reach environments
Authors: Antognoli L. , Panni L. , Cosoli G. , Scalise L. 
Published: February 2024

Abstract
Search and Rescue (SAR) operations in remote and hazardous environments are crucial for the rapid and accurate location of survivors, with a timely response being essential during the “golden hours” following a disaster. Recent technological advancements offer innovative solutions to enhance SAR efforts. This study aims to investigate the use of Laser Doppler Vibrometry (LDV) as a tool for remote vital sign assessment and explore its integration with Machine Learning (ML) techniques for accurate individual identification in challenging SAR scenarios. Various scenarios, such as different distances, difficult angles, and non-ideal body placements, are explored in the study to faithfully recreate hard-to-reach environments. Two models, the OS-Model trained with data acquired under optimal conditions and the AS-Model trained with data acquired including all the different conditions studied, were compared to evaluate classification performance. Results indicate that the LDV-assisted ML approach, particularly the AS-Model, exhibits promising outcomes with a higher median prediction accuracy of 0.93, emphasizing the importance of diverse and comprehensive datasets. However, limitations regarding accuracy at greater distances, smaller angles, and lower-body laser targeting must be considered for practical implementation.
Charge in non-thunderstorm clouds and fogs
Authors: Giles Harrison R , Nicoll Keri A , Ambaum Maarten HP 
Published: February 2024

Abstract
The global atmospheric electric circuit links charge separation in thunderclouds with current flow throughout the atmosphere. This current flow causes charge accumulation on the upper and lower boundaries of clouds and fogs. Thunderclouds are therefore not the only charged clouds in the atmosphere, and other forms of clouds, especially extensive horizontal layer clouds (stratus) are much more abundant globally. To investigate possible effects of charging of natural droplets in clouds, experiments have been undertaken using corona ion emission into fogs, releasing from within and above the fog. During the corona ion release the droplet size distribution was modified, with an increase in small drops. Further, when the ions were released over the fog, the reflectivity of the fog increased by ∼2%, about 30s later.
The effect of fog on atmospheric electric fields
Authors: Miller C , Nicoll K , Westbrook C , Harrison R G 
Published: February 2024

Abstract
Naturally occurring electric fields exist in the atmosphere as part of the global electric circuit. These fields are produced by global phenomena, but they are strongly modified by local conditions. One such local effect is fog, which is the reduction in visibility by droplets suspended in the air. For over a century, it has been known that fog can often result in larger values of electric field compared to that in clear air conditions. However, the physical processes controlling the electric field and its variability in fog are still not fully understood. More detailed information on this is required to assess whether electric field measurements can be used as a fog prediction method, which was suggested many decades ago but is still an open question. Furthermore, improving the understanding of electrical processes in fog will also help in related areas of research such as cloud electrification processes and the impact of charge on the behaviour of aerosol and droplets.
This study aims to fully characterise the electric field in fog using an extensive dataset of over 17 years, measured from the University of Reading Atmospheric Observatory, UK. This encompasses electric field, visibility, and meteorological data from over a hundred fog events, which allows us to examine the behaviour of electric fields in fog conditions statistically, rather than only focusing on individual case studies as is often the case in the literature. The long series of data from the site allows the variability in the electrical data during fog events to be more fully characterised than previously.
Evaluation of a modern point discharge sensor as an atmospheric electricity instrument
Authors: McGinness B , Harrison RG , Aplin KL , Airey MW 
Published: February 2024

Abstract
Point discharge sensors have been used for a long period of time, but are still not fully understood. The data collected by one of these sensors has been investigated along with electric field data in an attempt to parameterise the sensor. It was found that the sensor was best described by an equation with terms dependent on the atmospheric electric field and the first derivative of this electric field, with respect to time. This behaviour implies that both electrostatic and electrodynamic processes are important to the operation of the sensor. The inclusion of the electrodynamic term means that although this sensor is able to detect electrical disturbances, it is more difficult to recover the precise nature of the electric field using this sensor.
A charge emitter for use in evaluating aircraft rainfall enhancement
Authors: Nicoll K.A. , Escobar-Ruiz V. , Harrison R.G. , Ambaum M.H. , Alkamali A.A. 
Published: February 2024

Abstract
Charging of droplets is known to influence their properties and interactions, such as through modifying their evaporation, collisions or stability. Introducing additional charge into a droplet system, such as a natural fog or cloud may therefore provide a route to modify its behaviour. As aircraft are already used in rainfall enhancement activities by some national meteorological services, adapting their existing delivery systems to include charge release provides a convenient method with which to pursue this. Rainfall enhancement aircraft typically carry an array of under-wing tubes into which cloud seeding agents (e.g. salt or silver iodide) are contained in flares which are loaded pre-flight. Our approach for a charge release system is to construct a stand-alone device able to fit within an existing flare housing, to provide controlled release of ions by corona emission. The “flare emitter” device is battery powered and able to release either polarity of corona ions. It contains a programmable microcontroller (Arduino Nano) able to operate in a fixed sequence and record data to an internal memory card at 10Hz. Monitoring systems for the corona emission voltage and current are included, as well as environmental sensors for pressure, temperature and relative humidity.
Exploring the Use of Terrestrial Robots for Atmospheric Electricity Measurement
Authors: Zijlstra Gjosse , Aplin Karen L , Hunt Edmund R 
Published: February 2024

Abstract
Measuring the electric field is a central goal in electrostatics research, such as the study of electrostatics in atmospheric processes. It serves as a key indicator for various atmospheric phenomena, including the presence of lightning, dust or charged clouds. Traditionally, electric field measurements have been conducted from static platforms, with limited mobile measurements from airborne platforms such as balloons or, more recently, Unmanned Aerial Vehicles (UAVs). Here, we explore the potential of terrestrial robots to measure the electric field with some level of autonomy, such as during supervised navigation between user-defined waypoints. We mount a field mill on a four-wheeled rover and use a Global Navigation Satellite System (GNSS) to track the position of its measurements during an outdoor survey. The robot has a depth camera for 3D terrain mapping to contextualise local field measurements. We present plans for future research, including the use of semi-autonomous identification and exploration of electrostatic ‘hotspots’; and deployment of multiple robots (e.g., six) in a ‘sparse swarm’ configuration. We consider opportunities to employ such a robot system in environmental science or space research, for instance on Mars or the moon, where an understanding of electrostatic processes could be significant for future space missions.
Slow evaporation of a small sessile liquid drop: new solutions based on the electrostatic analogy
Authors: Lebedev-Stepanov P 
Published: February 2024

Abstract
Evaporating sessile drop of liquid deposited on horizontal surface is an important object of applications and theoretical investigations. The evaporating flow density dramatically depends on contact angle of the droplet. Previously, the dependence of the flux density on the polar angle was established for arbitrary contact angles. The expression has the form of an integral and is rather complicated for use in modelling algorithms. In this paper, we propose new exact solutions for the set of some specific contact angles (135-180 degrees). The analogy of the drop evaporation problem with a similar problem from the field of electrostatics of equipotential surfaces, which has been solved in general terms before us, was used. The results of British mathematician H.M. Macdonald and Soviet scientist G.A. Grinberg were used in the derivation. Thus, relatively simple expressions for the evaporation flux density were found.
Electric Field Measurement Techniques And Their Practical Applications
Authors: Noras Maciej A. 
Published: February 2024

Abstract
Static, quasi-static and low frequency electric fields are being used in many fields of science and engineering. They are utilized in research studies of fundamental properties of materials, exploration of high-energy physics, in biology and medicine, etc., but also in a multitude of practical applications such as precipitation, painting, xerography, to name a few. In all these endeavors it is a good practice to find out what the electric fields are in terms of value, direction, and temporal and spatial distribution. This information can be crucial for making the application successful. Electric fields are also being created by many naturally occurring and man-made phenomena. The aim of this paper is to present different options for electric field evaluation and measurement. Aside from traditional approaches, new concepts using machine learning in electric field assessment and interpretation are discussed. As technologies progress, electric field detection methods become a part of sensor fusion realm by providing additional capabilities in process, environmental and situational awareness monitoring. They can provide unique information enhancing our knowledge and understanding. Examples of such sensor integrations are shown and explained.
Electrostatic modelling of the Groza-2 discharge sensor on the Venera missions to Venus
Authors: Sukanjanajtee P , Aplin K L 
Published: February 2024

Abstract
The Soviet Venera 13 and 14 missions landed on the surface of Venus five days apart in 1982. An instrument called Groza-2, designed to search for thunderstorms, carried an electrode that recorded discharge currents in the lower atmosphere. In this paper a possible location and likely geometry of the electrode are deduced using the limited information available on Groza-2, combined with electrostatic modelling. The spacecraft’s geometry significantly screens the electrode potential, which helps to constrain the sensor’s size, shape and location. Due to its high atmospheric pressure, Venus is anticipated to have a high breakdown field, approximately 300 MV/m near the surface if linear scaling with pressure is assumed. The existence of a signal in the discharge sensor combined with the electrostatic screening of the spacecraft geometry implies there is a substantial potential difference between the atmosphere and the electrode.
Solvay method of estimating the risk of electrostatic ignition
Authors: Mark Egan Simon 
Published: February 2024

Abstract
IEC TS 60079-32-1 “ATEX - Electrostatic hazards, guidance” gives us the best practice to avoid ignition from electrostatic sources. In Solvay we follow this guideline but, when we find that our existing practice, at a particular site for a particular chemical process in a particular piece of equipment, does not comply with that guidance, we are faced with a difficult question: what priority should we give to putting it right? To answer that question we have to analyse the risk associated with electrostatic ignition sources for the particular process and that particular piece of equipment. It depends on many factors, including the frequency of the presence of an explosive atmosphere, the Minimum Ignition Energy of the flammable gas or combustible dust and the number of people who would be exposed to the blast wave or shrapnel from an explosion or the thermal radiation from a fire. Such considerations allow us to prioritize the risk in three levels, ranging from Risk 1 (Unacceptable), through Risk 2 (Intermediate) to Risk 3 = Acceptable. This paper shows how to estimate the risk level of scenarios involving electrostatic and indeed other ignition sources using the Solvay method.
Influence of the Reynolds number from Reτ
= 150 to 210 on size-dependent bipolar charging
Authors: Jantač S , Grosshans H 
Published: February 2024

Abstract
We recently found wall-bounded turbulence to suppress and control bipolar triboelectric charging of particles of identical material. This control is due to fluid modifying the motion of light particles. Thus, the particles’ charge distribution depends on their Stokes number distribution. More specifically, fluid forces narrow the bandwidth of the charge distribution, and bipolar charging reduces dramatically. Consequently, not the smallest but mid-sized particles collect the most negative charge. However, the influence of the Reynolds number or particle concentration on bipolar charging of polydisperse particles is unknown. This paper presents the charging simulations of same-material particles the in different wall-bounded flows. In a comprehensive study, we vary the Reynolds number from Reτ
= 150 to 210 and the particle number density from 4 × 109m-3 to 1 × 1010m-3 to further explore the influence of the carrier flow on bipolar charging. We model charge transfer based on the balance of transferable charge species. Such species can represent adsorbed ions transferred during collisions or free electrons captured into a lower energy state on the other surface. The turbulent flow is modeled via Direct Numerical Simulations (DNS) and is coupled to the particulate phase modeled via the Discrete Element Method (DEM). Overall, our multiphysics approach couples the fluid dynamics, electric field, triboelectric charging, and particle momentum into one complex simulation.
Polarity switch of PMMA powder transported through a PMMA duct
Authors: Xu Wenchao , Grosshans Holger 
Published: February 2024

Abstract
During pneumatic conveying, powder electrifies rapidly due to the high flow velocities. In our experiments, the particles even charge if the conveying duct is made of the same material, which might be caused by triboelectrification between two asymmetric contact surfaces. Surprisingly, we found the airflow rate to determine the polarity of the overall powder charge. This study investigates the charging of microscale PMMA particles in turbulent flows passing through a square PMMA duct. The particles are spherical and monodisperse. A Faraday at the duct outlet measured the total charge of the particles. At low flow velocities, the particles charged negatively after passing through the duct. However, the powder’s overall charge switched to a positive polarity when increasing the flow velocity.
Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana
Authors: Wang Jiayuan , Alli Abosede S , Clark Sierra N , Ezzati Majid , Brauer Michael , Hughes Allison F , Nimo James , Moses Josephine Bedford , Baah Solomon , Nathvani Ricky , D Vishwanath , Agyei-Mensah Samuel , Baumgartner Jill , Bennett James E , Arku Raphael E 
Published: February 2024

Abstract
Road traffic has become the leading source of air pollution in fast-growing sub-Saharan African cities. Yet, there is a dearth of robust city-wide data for understanding space-time variations and inequalities in combustion related emissions and exposures. We combined nitrogen dioxide (NO2) and nitric oxide (NO) measurement data from 134 locations in the Greater Accra Metropolitan Area (GAMA), with geographical, meteorological, and population factors in spatio-temporal mixed effects models to predict NO2 and NO concentrations at fine spatial (50 m) and temporal (weekly) resolution over the entire GAMA. Model performance was evaluated with 10-fold cross-validation (CV), and predictions were summarized as annual and seasonal (dusty [Harmattan] and rainy [non-Harmattan]) mean concentrations. The predictions were used to examine population distributions of, and socioeconomic inequalities in, exposure at the census enumeration area (EA) level. The models explained 88% and 79% of the spatiotemporal variability in NO2 and NO concentrations, respectively. The mean predicted annual, non-Harmattan and Harmattan NO2 levels were 37 (range: 1–189), 28 (range: 1–170) and 50 (range: 1–195) µg m−3, respectively. Unlike NO2, NO concentrations were highest in the non-Harmattan season (41 [range: 31–521] µg m−3). Road traffic was the dominant factor for both pollutants, but NO2 had higher spatial heterogeneity than NO. For both pollutants, the levels were substantially higher in the city core, where the entire population (100%) was exposed to annual NO2 levels exceeding the World Health Organization (WHO) guideline of 10 µg m−3. Significant disparities in NO2 concentrations existed across socioeconomic gradients, with residents in the poorest communities exposed to levels about 15 µg m−3 higher compared with the wealthiest (p < 0.001). The results showed the important role of road traffic emissions in air pollution concentrations in the GAMA, which has major implications for the health of the city’s poorest residents. These data could support climate and health impact assessments as well as policy evaluations in the city.
When 2D materials meet metals
Authors: Pirker Luka , Honolka Jan , Velický Matěj , Frank Otakar 
Published: February 2024

Abstract
This review delves into the intricacies of the interfaces formed between two-dimensional (2D) materials and metals, exploring a realm rich with fundamental insights and promising applications. Historically, our understanding of 2D materials emanated from studies employing dielectric substrates or suspended samples. However, integrating metals in the exfoliation and growth processes of 2D materials has opened up new avenues, unveiling various shades of interactions ranging from dispersive forces to covalent bonding. The resulting modifications in 2D materials, particularly transition metal dichalcogenides (TMDCs), offer more than a theoretical intrigue. They bear substantial implications for (opto)electronics, altering Schottky barrier heights and contact resistances in devices. We explore metal-mediated methods for TMDC exfoliation, elucidating the mechanisms and their impact on TMDC-metal interactions. Delving deeper, we scrutinize the fundamentals of these interactions, focusing primarily on MoS2 and Au. Despite the recent surge of interest and extensive studies, critical gaps remain in our understanding of these intricate interfaces. We discuss controversies, such as the changes in Raman or photoemission signatures of MoS2 on Au, and propose potential explanations. The interplay between charge redistribution, substrate-induced bond length variations, and interface charge transfer processes are examined. Finally, we address the intriguing prospect of TMDC phase transitions induced by strongly interacting substrates and their implications for contact design.
Preparation and performance analysis of micro-nano composite coatings reinforced with WC particles
Authors: Chen Baijiang , Xu Mengkuo 
Published: February 2024

Abstract
In order to research the effect of Tungsten carbide (WC) particles with different particle sizes additions in the reinforced coating, the strengthening coatings were produced by the compound process of high frequency induction cladding. The microstructure, phases and basic properties of the composite strengthening coatings were analyzed by means of metallographic microscope and FESEM. It was found that the addition of WC micro-nano particles further refined the grain phase in the strengthened coatings. The average hardness of the coating significantly increased with the increase of nanoparticle composition. The coating hardness of 30% na-WC involvement was the highest, 17% higher than that of 30% micron WC involvement. In the frictional wear experiments, the minimum amount of wear was the coating with the involvement of 20% micron WC and 10% na-WC, 20% less compared to that of 30%na-WC. The experiments showed that the introduction of an appropriate proportion of WC nanoparticles further improves the hardness of the reinforced coating. But due to the agglomeration phenomenon of nanoparticles, the hardness will be reduced instead as the proportion of WC nanoparticles further increased. The appropriate proportion of nanoparticles can effectively improve the wear resistance, but excessive proportion of nanoparticle addition can lead to a decrease in wear resistance. The involvement of 20% micron WC and 10%na-WC is the best addition ratio considering all factors.
Fabrication and characterization of durable superhydrophobic and superoleophobic surfaces on stainless steel mesh substrates
Authors: Saira Iqbal 
Published: February 2024

Abstract

Introduction. This study explores the fabrication of durable superhydrophobic and superoleophobic surfaces on stainless steel mesh, inspired by natural structures like lotus leaves. Achieving superoleophobicity, especially with enhanced durability, is challenging due to the lower surface tension of oils. Methodology. This novel technique involves using Perfluorooctyltriethoxysilane (PFOTES) and silicon dioxide nanoparticles to create re-entrant structures, low surface energy, and high roughness. This cost-effective approach ensures simplicity without requiring expensive equipment. Results. The resulting surfaces exhibit remarkable superoleophobic properties, with hexadecane and soybean oil contact angles reaching 170° and 163.8°, respectively. Scanning electron microscopy confirms successful fabrication, and wear abrasion tests demonstrate mechanical durability, with contact angles remaining high even after cyclic loading and sandpaper abrasion. Conclusion. This study presents a pioneering, cost-effective method for fabricating durable superoleophobic surfaces on stainless steel mesh. These surfaces hold promise for applications in self-cleaning coatings and oil-repellent materials.