Improving the energy yield of plasma-based NOX synthesis with in situ adsorption

Plasma-based NOX synthesis from air is a promising option to electrify nitrogen fixation. However, the energy efficiency of direct plasma-based NOX synthesis in a plasma reactor is severely limited by NOX decomposition in the plasma phase. In situ NOX adsorption on MgO improves the NOX energy yield in a dielectric barrier discharge (DBD) plasma reactor by a factor of 15

Simulation of aeolian sediment transport with inter-particle moisture using Discrete Particle Modelling

Moisture plays a critical role in the dynamics of aeolian sediment transport over coastal sandy beaches. It was found from field observations that the transport over wet beach surfaces is fundamentally different from that over dry surfaces (Swann, 2021). Despite many empirical findings about the moisture effect on the threshold and transport flux, the small-scale mechanics that inter-particle moisture affects the development of transport from initiation towards equilibrium remains poorly understood (Cornelis & Gabriels, 2003)

Crossing Boundaries:The Ethics of AI and Geographic Information Technologies

Over the past two decades, there has been increasing research on the use of artificial intelligence (AI) and geographic information technologies for monitoring and mapping varying phenomena on the Earth’s surface. At the same time, there has been growing attention given to the ethical challenges that these technologies present (both individually and collectively in fields such as critical cartography, ethics of AI and GeoAI). This attention has produced a growing number of critical commentaries and articles as well as guidelines (by academic, governmental, and private institutions) that have been drafted to raise these ethical challenges and suggest potential solutions. This paper presents a review of 16 ethical guidelines of AI and 8 guidelines of geographic information technologies, analysing how these guidelines define and employ a number of ethical values and principles (e.g., autonomy, bias, privacy, and consent). One of the key findings from this review is the asymmetrical mentioning of certain values and principles within the guidelines. The AI guidelines make very clear the potential of AI to negatively impact social and environmental justice, autonomy, fairness and dignity, while far less attention is given to these impacts in the geographic information guidelines. This points to a need for the geo-information guidelines to be more attentive to the role geographic information can play in disempowering individuals and groups.</p

Visualizing emoji usage in geo-social media across time, space, and topic

Social media is ubiquitous in the modern world and its use is ever-increasing. Similarly, the use of emojis within social media posts continues to surge. Geo-social media produces massive amounts of spatial data that can provide insights into users' thoughts and reactions across time and space. This research used emojis as an alternative to text-based social media analysis in order to avoid the common obstacles of natural language processing such as spelling mistakes, grammatical errors, slang, and sarcasm. Because emojis offer a non-verbal means to express thoughts and emotions, they provide additional context in comparison to purely text-based analysis. This facilitates cross-language studies. In this study, the spatial and temporal usage of emojis were visualized in order to detect relevant topics of discussion within a Twitter dataset that is not thematically pre-filtered. The dataset consists of Twitter posts that were geotagged within Europe during the year 2020. This research leveraged cartographic visualization techniques to detect spatial-temporal changes in emoji usage and to investigate the correlation of emoji usage with significant topics. The spatial and temporal developments of these topics and their respective emojis were visualized as a series of choropleth maps and map matrices. This geovisualization technique allowed for individual emojis to be independently analyzed and for specific spatial or temporal trends to be further investigated. Emoji usage was found to be spatially and temporally heterogeneous, and trends in emoji usage were found to correlate with topics including the COVID-19 pandemic, several political movements, and leisure activities.</p

Electron and lattice response to ultrafast laser excitation:Exploring temperature dynamics in transition metals

This thesis explores the interaction of ultrafast light pulses with metals at moderate irradiation intensities, leading to pronounced excitation and heating without phase transitions or damage. It examines the ultrafast heating dynamics in ruthenium (Ru) thin films through pump-probe measurements, alongside a detailed analysis of the changes on the Ru surface. Theoretically, it investigates the processes following light absorption by transition metals, focusing on the dielectric response of electrons and their coupling with lattice vibrations.The study of heating in Ru thin films, induced by femtosecond near-infrared laser irradiation, is a cornerstone of this thesis. It traces the transient electron and lattice temperatures, revealing unexpected thermoreflectance profiles that challenge the separate stages of two-temperature relaxation in Ru. Additional post-mortem analysis of Ru surfaces indicates that heat-induced film cracking is a primary degradation process under multi-shot, low-intensity irradiation.A significant portion of the thesis investigates the electron-phonon coupling mechanism in laser-excited transition metals. It establishes a strong link between the electron-phonon coupling strength and transient dynamics, suggesting that peculiarities in the thermoreflectance signal are due to a specific form of electron-phonon coupling, which varies with electron and lattice temperatures. Extensive first-principles simulations highlight the necessity of taking into account the often-overlooked effect of coupling different electron states with phonons, as it might significantly change the coupling values in the considered metals.Employing methods of density functional theory, the thesis also tackles the optical response of excited metals, which defines the observable thermoreflectance. It considers both electron-phonon and electron-electron scattering when studying fluence-dependent heating dynamics in metals. With Ru’s temperature-dependent optical properties at hand, the thesis reconciles experimental findings with theoretical models, proposing rapid electron-lattice equilibration in Ru due to strong electron-phonon coupling. This assumption allows the reproduction of experimental thermoreflectance dynamics by considering only lattice temperature dynamics and equilibrium-temperature-dependent optical properties. The peculiar heating dynamics in Ru is resolved: the experiment captures the lattice response but not the electron heating and two-temperature relaxation process, prompting further research to fully understand the absence of the two-temperature picture in Ru

Inline and Real-Time Microfluidic Relative Permittivity Sensor Using Highly Doped Silicon Sidewall Electrodes

This paper reports an inline sensor for thereal-time measurement of the relative permittivity of acontinuously flowing fluid, with electrodes that areelectrically isolated from the fluid. The sensor has beencharacterised for relative permittivity values ranging from1 to 80 – including water and water-containing mixtures –showing an accuracy within 3% of full scale. The proposedsensor contains multiple parallel microchannels, each ofwhich has parallel electrodes in the sidewall, resulting in alow pressure drop and high sensitivity while the internalvolume is only 50 nL. The fabrication technology isscalable: equally deep microchannels with widths of 5, 10,20, and 40 μm are demonstrated. The technology is alsocompatible with other inline sensors, enabling furtheron-chip integration

Range-wide camera traps reveal potential prey species for Javan leopards

Prey depletion poses a threat to large carnivores worldwide. The Javan leopard (Panthera pardus melas), the last remaining apex predator on the Indonesian island of Java, is facing numerous threats from human activities including poaching, habitat loss and prey depletion. Despite the fact that the Javan leopard is an adaptable and opportunistic predator capable of surviving in various environments, our understanding of its prey and predator-prey interactions is still limited, which is crucial for their conservation. Using camera trap data collected from four national parks (i.e., Ujung Kulon, Gunung Gede Pangrango, Meru Betiri, Alas Purwo) that represent four distinct terrestrial ecoregions across the island of Java, we investigated the species richness, relative abundance, and spatial-temporal overlap in activity patterns between the Javan leopard and other animals that coexist in the same location. Our analysis of 7461 independent photos, covering 12,983 camera trap days, revealed that areas with the presence of Javan leopards exhibited higher species richness and abundance compared to those without the presence of Javan leopards. In addition, we found that the activities of banteng (Bos javanicus), barking deer (Muntiacus muntjak), Javan deer (Rusa timorensis), Javan mousedeer (Tragulus javanicus), wild boar (Sus scrofa), junglefowl (Gallus spp.), spangled ebony langur (Trachypithecus auratus), Javan rhino (Rhinoceros sondaicus), long-tailed macaque (Macaca fascicularis) and dhole (Cuon alpinus) were highly overlapping with those of Javan leopards in space and time, suggesting that these species are potential candidate prey for Javan leopards. To our knowledge, this is the first comprehensive investigation of potential prey for the Javan leopard that utilizes camera traps from all four types of terrestrial ecoregions on Java Island. The findings of this study may serve as essential information for the conservation of this critically endangered species

Extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest:an overview of current practice and evidence

Cardiac arrest (CA) is a common and potentially avoidable cause of death, while constituting a substantial public health burden. Although survival rates for out-of-hospital cardiac arrest (OHCA) have improved in recent decades, the prognosis for refractory OHCA remains poor. The use of veno-arterial extracorporeal membrane oxygenation during cardiopulmonary resuscitation (ECPR) is increasingly being considered to support rescue measures when conventional cardiopulmonary resuscitation (CPR) fails. ECPR enables immediate haemodynamic and respiratory stabilisation of patients with CA who are refractory to conventional CPR and thereby reduces the low-flow time, promoting favourable neurological outcomes. In the case of refractory OHCA, multiple studies have shown beneficial effects in specific patient categories. However, ECPR might be more effective if it is implemented in the pre-hospital setting to reduce the low-flow time, thereby limiting permanent brain damage. The ongoing ON-SCENE trial might provide a definitive answer regarding the effectiveness of ECPR. The aim of this narrative review is to present the most recent literature available on ECPR and its current developments.</p

Compact Micro-Coriolis Mass-Flow Meter with Optical Readout

This paper presents the first nickel-plated micro-Coriolis mass-flow sensor with integrated optical readout. The sensor consists of a freely suspended tube made of electroplated nickel with a total length of 60 mm, an inner diameter of 580 µm, and a wall thickness of approximately 8 µm. The U-shaped tube is actuated by Lorentz forces. An optical readout consisting of two LEDs and two phototransistors is used to detect the tube motion. Mass-flow measurements were performed at room temperature with water and isopropyl alcohol for flows up to 200 g/h and 100 g/h, respectively. The measured resonance frequencies were 1.67 kHz and 738 Hz for water and 1.70 kHz and 752 Hz for isopropyl alcohol for the twist and swing modes, respectively. The measured phase shift between the two readout signals shows a linear response to mass flow with very similar sensitivities for water and isopropyl alcohol of (Formula presented.) and (Formula presented.), respectively.</p

On the film thickness in grease lubricated deep groove ball bearings

Most rolling element bearings use grease as a lubricant. The service life of a bearing is determined by the bearing fatigue life and grease life. Both are influenced by the quality of lubrication, which is strongly determined by the thickness of the lubricating film. The optimal selection of a lubricating grease and/or the prediction of grease and/or bearing life can only be done properly if the film thickness can be determined. However, until now, there is no equation to predict film thickness in grease lubricated bearings. In practice, the equations that were derived for oil lubrication are used. In this thesis, the film thickness immediately after the churning phase is studied under various conditions on different bearings and greases. An improved electrical capacitance method is developed to measure the film thickness by using an electrical model of the bearing, including the effect of starvation. It is shown that the film thickness immediately after churning is determined by the dynamics of the flow of lubricants in and around the contacts and not by oil released by the grease after churning (bleed). It is observed that the film thickness in a grease lubricated bearing is almost constant at higher speeds.It is demonstrated that the level of starvation under pure axial load can be well described using only the product of base oil viscosity, half contact width, and linear speed (ηbu). It is also shown that bearing size/geometry has little to no influence in determining the level of starvation in the ηbu concept. The film thickness study in radially loaded bearings and bearings under combined (axial+radial) loads showed that there is an additional replenishment at the lower loaded zones. This is due to a larger ‘gap’ between the ball and the groove in the low load zone causing a reduction in resistance to viscous flow, thereby increasing the flow of lubricant towards the contacts. Finally, a master curve is created that can be used to calculate the film thickness in grease lubricated ball bearings under radial, axial and combined loads