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This study explores the use of air-fed atmospheric pressure plasma jets (APPJs) as a pre-joining treatment for 3D carbon fiber-reinforced carbon matrix composites (C/C) with the aim of both creating a textured surface that resembles a brush structure and improving the joint strength. The effects of various treatment time lengths on the mass loss, etching depth, and surface texture were investigated using SEM and confocal microscopy. An optimal process time of 30 s was selected, while keeping the other process parameters fixed (air flow of 1750 l/h and nozzle-sample distance of 5 mm). Wetting tests were conducted at 1000 °C, on both untreated and pre-treated C/C surfaces by means of liquid TiCuNi brazing alloy, and low contact angles of about 20° were measured. C/C–TiCuNi–C/C and C/C–TiCuNi–Cu joints were then produced, and their interfacial reactivity was evaluated. The apparent shear strength measured for the APPJ-treated C/C–Cu joints was 140 % higher than the value recorded for the untreated joints, thus confirming the effectiveness of the treatment. Even though a further investigation is needed in which an optimization of the process parameters should be included, this preliminary study has revealed the viability of APPJ as a promising technique to enhance the bonding of C/C composites in dissimilar assemblies and to improve the joint quality. [ABSTRACT FROM AUTHOR]

The impacts of hydrometeor-related processes on the development and evolution of the "21·7" extremely heavy rainfall in Zhengzhou were investigated using WRF simulations. Surface precipitation was determined by the hydrometeor microphysical processes (all microphysical source sink terms of hydrometeors) and macrophysical processes (local change and flux convergence of hydrometeors). The contribution of hydrometeor macrophysical processes was commonly less than 10%, but could reach 30%–50% in the early stage of precipitation, which was largely dependent on the size of the study area. The macrophysical processes of liquid-phase hydrometeors always presented a promotional effect on rainfall, while the ice-phase hydrometeors played a negative role in the middle and later stages of precipitation. The distributions of microphysical latent heat corresponded well with those of buoyancy and vertical velocity (tendency), indicating that the phase-change heating was the major driver for convective development. Reasonable diagnostic buoyancy was obtained by choosing an area close to the convective size for getting the reference state of air. In addition, a new dynamic equilibrium involving hydrometeors with a tilted airflow was formed during the heavy precipitation period (updraft was not the strongest). The heaviest instantaneous precipitation was mainly produced by the warm-rain processes. Sensitivity experiments further pointed out that the uncertainty of latent heat parameterization (±20%) did not significantly affect the convective rainfall. While when the phase-change heating only altered the temperature tendency, its impact on precipitation was remarkable. The results of this study help to deepen our understanding of heavy rainfall mechanisms from the perspective of hydrometeor processes. [ABSTRACT FROM AUTHOR]

This experimental study investigated the influence of different turbine guide vane parameters on the ignition limit and light-round processes in a triple-dome combustor. It was found that for the triple-dome combustor, the minimum fuel/air ratios at the ignition limit all show a trend of initial decrease followed by subsequent increase with the growth of incoming air mass flow rate. The ignition fuel/air ratio decreases with the increase in turbine blockage ratio, and the optimal scheme is achieved with a blockage ratio of 0.8. Under the condition where the incoming air mass flow rate is 0.089 kg/s, the light-round time decreases with the increase in fuel/air ratio, and the light-round time of the combustor without guide vanes is shorter than that of the other schemes. With the increase in incoming air mass flow rate, the light-round time of the schemes with guide vanes is shortened. Under the same incoming air mass flow rate and fuel/air ratio, the increase in the blockage ratio will lead to an increase in the light-round time of the triple-dome combustor. [ABSTRACT FROM AUTHOR]

An experimental study to investigate the flow of liquid jet issued from a high aspect ratio nozzle slit into an incoming airflow by changing the orientation angle from the incoming free-stream was performed. A two-dimensional liquid sheet emerged from the narrow slit into the subsonic air crossflow. Different orientation angles between 0 and 90 degrees were studied. High-speed photography and shadowgraphy techniques were utilized to visualize the flow physics. The influence of the slit orientation angle on the flow morphology and the flow regimes of liquid sheets was investigated. Some fluid flow parameters were obtained by analyzing the images. The changes in breakup height of different orientations were measured. A model was offered for the breakup height of the liquid sheet based on the liquid-to-gas momentum ratio, gas Weber number, and a new non-dimensional parameter as a representation of the angle of slit orientation. Also, the defined sheet trajectory for each orientation angle was obtained, and the variations were examined. Empirical correlations for the defined trajectory of the sheet in terms of liquid to gas momentum ratio and gas Weber number for each orientation angle were proposed. [ABSTRACT FROM AUTHOR]

Respiratory–swallowing coordination (RSC) is well established as an essential airway‐protective mechanism. Previous studies have used nasal airflow and/or kinematic rib cage and abdominal measures to assess respiration surrounding swallowing, meaning that the direct influence of oral respiration on RSC remains unknown. This study used a partitioned oronasal facemask to compare respiratory phase patterns measured using isolated nasal airflow with those measured using combined oronasal airflow during non‐ingestive and ingestive swallowing tasks. Twenty‐four healthy individuals with no respiratory or swallowing disorders were assessed at rest and during cued dry, 10 mL water, continuous drinking and cracker swallowing tasks. Respiratory phase patterns were determined for discrete swallows using the nasal and combined oronasal channels separately. There was variable agreement between respiratory phase patterns according to the nasal and oronasal channels across swallowing conditions. The frequency of exhale–swallow–exhale, inhale–swallow–exhale and exhale–swallow–inhale patterns increased by 2%–3% each with the addition of oral flow data to nasal data, whereas the prevalence of inhale–swallow–inhale and ambiguous patterns decreased. This suggests that estimates of respiratory phase patterns are altered minimally by inclusion of oral respiratory estimates in a healthy sample. There were several additional findings of note, including lower within‐participant, within‐session trial consistency (test–retest reliability) than expected, suggesting high variability in respiratory phase patterns across trials. Additionally, data showed evidence of swallowing non‐respiratory flow at the beginning and end of the respiratory–swallowing pause, moving in both inward and outward directions, potentially expanding current understanding of swallowing non‐respiratory flow. Further in‐depth physiological investigations are required to improve understanding of these findings. [ABSTRACT FROM AUTHOR]

Highly performance flexible strain sensor is a crucial component for wearable devices, human‐machine interfaces, and e‐skins. However, the sensitivity of the strain sensor is highly limited by the strain range for large destruction of the conductive network. Here the quasi‐1D conductive network (QCN) is proposed for the design of an ultra‐sensitive strain sensor. The orientation of the conductive particles can effectively reduce the number of redundant percolative pathways in the conductive composites. The maximum sensitivity will reach the upper limit when the whole composite remains only "one" percolation pathway. Besides, the QCN structure can also confine the tunnel electron spread through the rigid inclusions which significantly enlarges the strain‐resistance effect along the tensile direction. The strain sensor exhibits state‐of‐art performance including large gauge factor (862227), fast response time (24 ms), good durability (cycled 1000 times), and multi‐mechanical sensing ability (compression, bending, shearing, air flow vibration, etc.). Finally, the QCN sensor can be exploited to realize the human‐machine interface (HMI) application of acoustic signal recognition (instrument calibration) and spectrum restoration (voice parsing). [ABSTRACT FROM AUTHOR]

Simple Summary: Ants are a widespread and highly abundant group of animals in almost all terrestrial ecosystems. Nesting sites are important for ants, as the nest protects them against predators and can ensure optimal conditions for the brood development. We studied the nest site selection by Temnothorax crassispinus ant colonies, which typically inhabit empty acorns. During this study, we used artificial nest sites with slits in the nest wall, mimicking the cracks in acorns under natural conditions. We found that the ant colonies preferred artificial nest sites without these slits. The absence of cracks in acorns could be an indication of the durability of potential nest sites; thus, we propose that choosing acorns without such damage could be beneficial for the ant colonies. For ants, nests provide a refuge against predators and protection from environmental factors. Thus, choosing a good nest site is important for an ant colony, but nest sites are limited resources. Ants of the genus Temnothorax inhabit small cavities in, e.g., acorns, twigs and under rocks. Earlier, it was shown that the ants are able to choose a superior site. In this study, using binary choice tests, we studied the nest site selection by Temnothorax crassispinus ant colonies that typically inhabit empty acorns. For this purpose, we used artificial nest sites without and with an additional slit in the nest wall, mimicking the cracks in potential nest sites under natural conditions. We found that the ant colonies preferred artificial nest sites without these slits. However, no difference in the number of colonies inhabited nest sites with a slit vs. those without a slit was found when the slits were closed using transparent food foil, which prevented the air flow while keeping an inflow of light. What is more, additional light through the hole in the red filter covering the artificial nest sites had no influence on the nest site selection. The results of this study suggest that the air flow through a slit in the nest site wall, rather than additional light, influences the nest site selection. The absence of cracks, e.g., in acorns, could be an indication of the durability of potential nest sites. Thus, choosing a cavity without such damage could be beneficial for the ant colonies. [ABSTRACT FROM AUTHOR]

Radon concentrations in the tourist part of the Cango cave were measured using 25 strategically placed electret ion chambers. Airflow rates were also measured and found to be less than 1 m/s throughout the cave. An IDW interpolated radon concentration overlay was constructed using QGIS and overlayed on maps of the cave. The maximum radon concentration of 2625 Bq/m3 was measured in the Grand Hall, located in the central part of the cave following a narrow passage. The initial part of the cave near the entrance exhibited normal cave breathing characteristics, with radon concentrations of less than 300 Bq/m3. The deepest section of the cave, however, demonstrated an unexpected decrease in radon levels, temperature, and humidity. The average radon concentration in the Cango cave, measured at 1265 Bq/m3, is relatively low compared to other caves worldwide that need mitigation measures according to the International Commission on Radiological Protection (ICRP). [ABSTRACT FROM AUTHOR]

The aim of this paper was to characterize the warm and dry compound events (WD days) in Poland during the period of 1966–2023, focusing on assessing the frequency and intensity of such events and their spatial and temporal variability, as well as on the driving factors of warm and dry compound events. WD days are those days that have a maximum temperature equal to or higher than the 90th percentile and the precipitation on that day and the 14 preceding days are equal to or less than the 25 percentile. During 1966–2023, the frequency of WD days increased significantly, mainly in April, the summer months, and December. Higher temperatures favored the occurrence of WD days from March to November, but, in winter months, the heat did not favor the occurrence of WD days. The exception was December, when high temperatures in the first part of the analyzed period did not favor the occurrence of a dry day, whereas, in the second part, it did. The strongest influence on the frequency of WD days had the East Atlantic pattern, where air flowed over Poland from the southwest. Warm and humid air flowing from the Atlantic Ocean must overcome the mountain barrier; therefore, it flows to Poland as warm and dry air. From spring to autumn, the WD days were related to an increase in the geopotential height in central Eastern Europe, and, in the winter, they were related with blocking over the Balkans. [ABSTRACT FROM AUTHOR]

The study evaluated a new model of a Plair SA airflow cytometer, Rapid-E + , and assessed its suitability for airborne pollen monitoring within operational networks. Key features of the new model are compared with the previous one, Rapid-E. A machine learning algorithm is constructed and evaluated for (i) classification of reference pollen types in laboratory conditions and (ii) monitoring in real-life field campaigns. The second goal of the study was to evaluate the device usability in forthcoming monitoring networks, which would require similarity and reproducibility of the measurement signal across devices. We employed three devices and analysed (dis-)similarities of their measurements in laboratory conditions. The lab evaluation showed similar recognition performance to that of Rapid-E, but field measurements in conditions when several pollen types were present in the air simultaneously showed notably lower agreement of Rapid-E + with manual Hirst-type observations than those of the older model. An exception was the total-pollen measurements. Comparison across the Rapid-E + devices revealed noticeable differences in fluorescence measurements between the three devices tested. As a result, application of the recognition algorithm trained on the data from one device to another led to large errors. The study confirmed the potential of the fluorescence measurements for discrimination between different pollen classes, but each instrument needed to be trained individually to achieve acceptable skills. The large uncertainty of fluorescence measurements and their variability between different devices need to be addressed to improve the device usability. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are employed in a range of devices due to their high energy and power density. However, the increased power density of LIBs raises concerns regarding their safety when subjected to external abuse. The thermal behavior is influenced by a number of factors, i.e., the state of charge (SoC), the cell chemistry and the abuse conditions. In this study, three distinct cylindrical Li-ion cells, i.e., lithium nickel cobalt aluminum oxide (NCA), lithium titanate oxide (LTO), and lithium iron phosphate (LFP), were subjected to thermal abuse (heating rate of 5 °C/min) in an air flow reactor, with 100% SoC. Venting and thermal runaway (TR) were recorded in terms of temperature and pressure, while the emitted products (gas, solid, and liquid) were subjected to analysis by FT-IR and ICP-OES. The concentrations of the toxic gases (HF, CO) are significantly in excess of the Immediate Danger to Life or Health Limit (IDLH). Furthermore, it is observed that the solid particles are the result of electrode degradation (metallic nature), whereas the liquid aerosol is derived from the electrolyte solvent. It is therefore evident that in the event of a LIB fire, in order to enhance the safety of the emergency responders, it is necessary to use appropriate personal protective equipment (PPE) in order to minimize exposure to toxic substances, i.e., particles and aerosol. [ABSTRACT FROM AUTHOR]

The application of turbulators to improve thermal performance and thermal enhancement in heat exchangers because of the significance of energy management and optimization is one of the interesting topics for researchers. Analysis of aerodynamic turbulator in internal flow has been less discussed in previous studies. Therefore, the present work focuses on the effect of a perforated sphere turbulator in a circular pipe with square, circular, oval, and hexagonal geometry holes on turbulent flow characteristics and thermal performance. These turbulators are placed with equal obstruction against the flow of air passing inside the pipe at Re = 6000–24000 in wall conditions of constant heat flux. Ansys Fluent software is used for numerical solutions, and the results are validated with an experimental paper. According to the results, the hexagonal geometry creates less pressure drop than other geometries. The thermal performance in the pipe with innovative aerodynamic turbulators is improved compared to the smooth pipe and the pipe equipped with conventional turbulators. The highest thermal performance of 1.256 is obtained for the turbulator with an oval hole. Also, the range of Nusselt number compared to the plain pipe for turbulator with circular, hexagonal, square, and oval holes increases by 1.97–2.46, 2.24–2.65, 1.58–1.89, and 2.48–2.81 times, respectively. The effect of the proposed new turbulators was compared with previous studies in this field, and the results are promising. [ABSTRACT FROM AUTHOR]

[Display omitted] • We proposed an SPA based on a Kresling-like pattern with a rigid skeleton by observing the cloning and moving behaviors from salps. • An extensible inserting structure is innovatively designed to replace the creases in traditional Kresling patterns. • The SPA can perform an axial contraction motion without twisting and a controllable bending motion. • The number of layers of Kresling-like patterns is changeable by adding or reducing skeleton components. • The elongation can reach to above 162% and the output force can reach to above 6.36 N. Biomimetic soft pneumatic actuators (SPA) with Kresling origami patterns have unique advantages over conventional rigid robots, owing to their adaptability and safety. Inspired by cloning and moving behaviors observed from salps, we proposed an SPA based on a Kresling-like pattern with a rigid skeleton. The elongation and output force were tested, and the effectiveness of the applications with the SPA was evaluated. The proposed SPA consists of rigid skeletons and a soft skin. The rigid skeletons are constructed using layers of Kresling-like patterns, while a novel extensible inserting structure is devised to replace the folds found in conventional Kresling patterns. This innovative approach ensures that the SPA exhibits axial contraction/expansion motion without any twisting movement. To mimic the bionic characteristics of swimming and ingesting progress of salps, the proposed SPA can perform an axial contraction motion without twisting and a controllable bending motion based on multi-layered Kresling-like patterns; to mimic the cloning and releasing life phenomena of salps, the number of layers of Kresling-like patterns is changeable by adding or reducing skeleton components according to the practical needs. The experimental elongation results on the SPA with multiple layers of Kresling-like patterns show that the elongation can increase to above 162% by adding layers; the experimental output force results show that the three-layer SPA can provide 6.36 N output force at an air flow rate of 10 L/min, and the output force will continue to increase as the number of layers of Kresling-like pattern increases or the air flow rate increases. Further, we demonstrate the applications of the SPA in soft grippers, scissor grippers, claw grippers and pipe crawlers. Our proposed SPA can avoid twisting in the radial contraction motion with high elongation and output force, and provide the practical guidance for bio-inspired soft robotic applications. [ABSTRACT FROM AUTHOR]

uDALES is an open-source multi-physics microscale urban modelling tool, capable of performing large-eddy simulation (LES) of urban airflow, heat transfer, and pollutant dispersion. We present uDALES v2.0, which has two main new features: (1) an improved parallelisation that prepares the codebase for conducting exascale simulations and (2) a conservative immersed boundary method (IBM) suitable for an urban surface that does not need to be aligned with the underlying Cartesian grid. The urban geometry and local topography are incorporated via a triangulated surface with a resolution that is independent of the fluid grid. The IBM developed here includes the use of wall functions to apply surface fluxes, and the exchange of heat and moisture between the surface and the air is conservative by construction. We perform a number of validation simulations, ranging from neutral, coupled internal–external flows and non-neutral cases. We observe close agreement with the relevant literature, both in cases in which the buildings are aligned with the Cartesian grid and when they are at an angle. We introduce a validation case specifically for urban applications, for which we show that supporting non-grid-aligned geometries is crucial when solving surface energy balances, with errors of up to 20 % associated with using a grid-aligned geometry. [ABSTRACT FROM AUTHOR]

In this paper, we present a cost-effective system for monitoring and controlling alkaline electrolyzers, intending to improve hydrogen gas production on a laboratory scale. Our work includes two main innovations. Firstly, we suggest an approach to calibrate a standard air flow meter to accurately measure the flow of hydrogen-rich gas from electrolyzers, improving measurement accuracy while keeping costs low. Secondly, we introduce a unique cascade control method to manage hydrogen-rich gas production in the electrolyzer, ensuring precise control over gas flow rates. By combining affordable, energy-efficient devices with a PI control system, we achieve efficient gas production through electrolysis, replacing manual control approaches. Experimental results confirm the effectiveness of our cascade control method, demonstrating stable operation with minimal errors. These results provide a foundation for further research into control strategies to enhance the performance of electrolytic cells. [ABSTRACT FROM AUTHOR]

Background: At the time of the COVID-19 pandemic, devastating incidents increased due to frequent oxygen administration to patients. The dangers associated with the use of oxygen, especially through local enrichments and formation of "oxygen clouds", have been well understood for years. Nevertheless, dramatic incidents continue to occur, since fire hazard increases exponentially with oxygen concentrations above 23%. Rescue helicopters are at a particular high risk, because of technical reasons such as oxygen use in a very small space, surrounded by kerosene lines, electronic relays and extremely hot surfaces. Methods: In this study three different sized rescue helicopter models (Airbus H135, H145 and MD902) were examined. Oxygen enrichment in the cabin was measured with an oxymeter during a delivery rate of 15 l/min constant flow for 60 min. Furthermore, the clearance of the enriched atmosphere was tested in different situations and with different ventilation methods. To make the airflow visible, a fog machine was used to fill the helicopter cabin. Results: Oxygen accumulation above 21% was detected in every helicopter. After 10–15 min, the critical 23% threshold was exceeded in all three aircrafts. The highest concentration was detected in the smallest machine (MD902) after 60 min with 27.4%. Moreover, oxygen clouds persisted in the rear and the bottom of the aircrafts, even when the front doors were opened. This was most pronounced in the largest aircraft, the H145 from Airbus Helicopters. Complete and rapid removal of elevated oxygen concentrations was achieved only by cross-ventilation within 1 min. Conclusions: Oxygen should be handled with particular care in rescue helicopters. Adapted checklists and precautions can help to prevent oxygen accumulation, and thus, fatal incidents. To our knowledge, this is the first study, which analyzed oxygen concentrations in different settings in rescue helicopters. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) panels are similar in many aspects to the leaves of trees, both are standing in the Sun to capture the sunlight, however, PV panels get soiled especially in desert areas, while the leaves remain clean to a very good extent. The question is, why leaves remain clean while PV panels get soiled quite easily? The leaves are hanging on the stem of trees and these stems are flexible to motion, such that if the wind blows in any direction over the stem it vibrates allowing any deposited particle to fall off the surface. The objective of this research is to develop a fixation method for PV panels similar to the stems of trees, such that the panel can vibrate as the wind blows in order to minimize dust accumulation. Different fixation methods for the PV panel are designed, and the air flow around the panel is simulated using the CFD package Ansys Fluent. It has been found that a PV panel pivoted at its lower edge, such that it can revolve around the lower edge, together with a vertical wind shield attached to its upper edge and a spring attached at the middle of its backside has the largest vibration amplitude due to the applied wind compared to the other designs. Experiments have been done to infer the influence of the new fixation method of the PV panel on dust accumulation over the panel. After 6 weeks of operation, it has been found that the efficiency of the PV panel that is flexibly fixed has dropped by only 5%, while the efficiency of the panel that is rigidly fixed has dropped by 25%. It can be concluded that a PV panel operating a light post should be fixed on a flexible base that allows the panel to vibrate as the wind blows over it in order to mitigate dust. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) panels are similar in many aspects to the leaves of trees, both are standing in the Sun to capture the sunlight, however, PV panels get soiled especially in desert areas, while the leaves remain clean to a very good extent. The question is, why leaves remain clean while PV panels get soiled quite easily? The leaves are hanging on the stem of trees and these stems are flexible to motion, such that if the wind blows in any direction over the stem it vibrates allowing any deposited particle to fall off the surface. The objective of this research is to develop a fixation method for PV panels similar to the stems of trees, such that the panel can vibrate as the wind blows in order to minimize dust accumulation. Different fixation methods for the PV panel are designed, and the air flow around the panel is simulated using the CFD package Ansys Fluent. It has been found that a PV panel pivoted at its lower edge, such that it can revolve around the lower edge, together with a vertical wind shield attached to its upper edge and a spring attached at the middle of its backside has the largest vibration amplitude due to the applied wind compared to the other designs. Experiments have been done to infer the influence of the new fixation method of the PV panel on dust accumulation over the panel. After 6 weeks of operation, it has been found that the efficiency of the PV panel that is flexibly fixed has dropped by only 5%, while the efficiency of the panel that is rigidly fixed has dropped by 25%. It can be concluded that a PV panel operating a light post should be fixed on a flexible base that allows the panel to vibrate as the wind blows over it in order to mitigate dust. [ABSTRACT FROM AUTHOR]

This study presents the potential of using a natural ventilation system integrated with different combinations of enhancement techniques. The focus was on the perspective of using such configurations of passive ventilation systems (PVSs) in buildings located in different European cities. This work presents the results of obtaining the level of volumetric air flow rate for considering natural ventilation systems. Furthermore, the influences of local weather conditions (temperature, solar radiation, wind speed) were analyzed. Moreover, the year-round operation of all systems was presented. Also noted was the limitation of using PVSs based on the natural draft effect, additionally assisted by wind turbine ventilators in all European localizations. However, for the cities located in the northern part of Europe, it was confirmed that such a system can still meet minimum hygienic recommendations. It was also noted that a system additionally supported by a solar chimney is a much better solution. The best system was a PVS supported by a wind turbine ventilator and solar chimney integrated with PCM accumulation mass. The system should be additionally supported by waste heat from low-temperature sources. In the presented study, a high potential to reduce CO2 emission from building stock by the recommended system is additionally highlighted. However, there is still a need to analyze the proposed solutions by additional field tests and experimental investigations. [ABSTRACT FROM AUTHOR]

A thermal dynamic disaster in the goaf is one of the most serious coal mine disasters formed by coal spontaneous combustion and gas interweaving. However, the influence of the high-temperature hidden fire source formed in the goaf on the evolution law of thermal dynamic disasters is not clear, and effective prevention and control measures cannot be taken. Therefore, this paper uses the experimental platform of thermal dynamic disaster in the goaf to study the influence of different fire point positions on the development of thermal dynamic disaster in the goaf through a similar simulation experiment of thermal dynamic disaster evolution in the goaf and analyzes the corresponding relationship between temperature and CO concentration in the upper corner. The results show that under different locations of heat source, the high-temperature heat source of coal spontaneous combustion migrates to the air leakage side with sufficient oxygen supply, and an oxygen-poor circle is formed near the ignition point. Under the action of air leakage flow, CH4 accumulates in the deep part of the goaf on the return air side. Due to the increase in coal, part of CH4 is produced, which leads to the increase in concentration of CH4 at the ignition point. Under the action of different heat sources, the changing trend of concentration of CO and temperature in the return air corner is the same, but the temperature change in the return air corner shows a lag compared with the change in the concentration of CO, so concentration monitoring of CO can reflect the evolution process of the fire field in the goaf more quickly than temperature monitoring. [ABSTRACT FROM AUTHOR]

Odours used by insects for foraging and mating are carried by the air. Insects induce airflows around them by flapping their wings, and the distribution of these airflows may strongly influence odour source localisation. The flightless silkworm moth, Bombyx mori, has been a prominent insect model for olfactory research. However, although there have been numerous studies on antenna morphology and its fluid dynamics, neurophysiology, and localisation algorithms, the airflow manipulation of the B. mori by fanning has not been thoroughly investigated. In this study, we performed computational fluid dynamics (CFD) analyses of flapping B. mori to analyse this mechanism in depth. A three-dimensional simulation using reconstructed wing kinematics was used to investigate the effects of B. mori fanning on locomotion and pheromone capture. The fanning of the B. mori was found to generate an aerodynamic force on the scale of its weight through an aerodynamic mechanism similar to that of flying insects. Our simulations further indicate that the B. mori guides particles from its anterior direction within the ~ 60° horizontally by wing fanning. Hence, if it detects pheromones during fanning, the pheromone can be concluded to originate from the direction the head is pointing. The anisotropy in the sampling volume enables the B. mori to orient to the pheromone plume direction. These results provide new insights into insect behaviour and offer design guidelines for robots for odour source localisation. [ABSTRACT FROM AUTHOR]

Electric motors with high-power densities are required for the implementation of electromobility. To achieve this, direct liquid cooling methods are increasingly being considered, in which oil is injected into the motor compartment. This results in a two-phase flow that can be used for efficient cooling. However, the oil, which can also penetrate the air gap between the rotor and stator, can also lead to additional losses due to increased friction. Since little is known about the two-phase flow in such systems, especially in the air gap, it is investigated by means of simple optical visualizations and high-speed laser-induced fluorescence imaging as well as torque measurements. The measurements are carried out in the air gap of an optically accessible generic model of a directly cooled electric motor. Speed variations were performed from 100 to 2000 rpm, and three different two-phase flow regimes were observed. At low speeds (Flow Regime 1), the air gap is filled locally with oil in radial direction, in the medium speed range (Flow Regime 2) with foam, while at high speeds (Flow Regime 3) separated films were observed on the rotor and stator. The torque difference between the two-phase and single-phase operation, which quantifies the mechanical losses due to the injected oil, increased continuously due to the oil in the air gap until it reached a maximum in Flow Regime 2 due to foam formation. In Flow Regime 3, the torque difference was negative. This was attributed to the fact that the grooves in the stator were filled with oil, thus reducing the turbulence generation of the air flow. [ABSTRACT FROM AUTHOR]

Atmospheric convection across the northern inter-Americas is modulated by trade-wind subsidence and subtropical easterly waves from June to October. Northward migration of the equatorial trough is coupled to the meridional circulation (MC) and surface temperatures above 27ºC. Forming a MC index via S-N height sections of total and anomalous streamfunction, statistical relationships are examined which focus on Jun-Oct season when the South American monsoon is quiescent. Both east Pacific and tropical north Atlantic exhibit cool ocean – dry atmosphere response to an intensified MC. During periods of faster MC, composite humidity is depleted over the Caribbean 10–25 N in conjunction with westerly wind shear, thereby limiting atmospheric convection. The ocean response to intensified MC is evaporative cooling and a deep layer of increased salinity in the Caribbean, that may sustain anomalous air-sea interactions. Long-term trends reveal intensification of the MC in boreal summer: rising over the Amazon, subsiding over the Caribbean, inter-connected by lower and upper airflows. The annually pulsed MC conspires with inter-decadal trends to produce many of the features presented. [ABSTRACT FROM AUTHOR]

Part of the gaseous carbon dioxide (CO2) produced in karst soils / epikarst is transported into underground cavities / caves during the growing season by advective flux, diffusive flux, and flux associated with degassing of seeping water. In dynamic caves, accumulated CO2 is released into the outside atmosphere during the autumn-winter period through advective flux associated with ventilation of the cave in the upward airflow mode. This case study from the Moravian Karst (MK) showed that the net weight of CO2 released annually from the Sloup-Šošůvka Caves (total volume of 131,580 m3 and a total area of 17,950 m2) into the external atmosphere was 348 kg. Extrapolating this value to all known MK caves (area about 352,080 m2) yielded a total of CO2 flux of 6820 kg yr−1. This flux is representing only 0.024‰ of the annual soil respiration from entire MK area (about 2.81 × 108 kg CO2 yr−1). [ABSTRACT FROM AUTHOR]

Humidification and dehumidification (HDH) desalination units compared with the other thermal desalination systems have relative advantages due to working under ambient pressure and low temperatures and are more attractive. In this research, the application of an HDH desalination unit with indirect‐contact of air and water streams in a steam power plant is investigated. To increase the energy efficiency of the system, a closed air cycle has been considered. Also, by application of the closed water cycle in the humidifier, the recovery rate of the desalination unit increases according to the concentration of discharge flow. The flow rate of boilers blowdown in the studied steam power plant is around 2.2 kg/s and can be used as a unique source of required thermal energy in the desalination system to produce freshwater from power plant chemical effluents. On the basis of the available cooling water (30 m3/day), this stream is considered as the limiting flow in the modeling. The detailed design of different parts of the desalination unit, including the humidification tower, condensers, wet air circulation fans, the required pumps, and the heat exchanger, is presented in this study. The maximum production of freshwater and the minimum energy intensity are obtained for the circulating air flow rate of 4 kg/s. By 14% recovery of lost steam in the power plant, 20.8 m3/h of desalinated water is produced. The gain output ratio and the energy intensity of the system are 1.025 and 2201 kJ/L, respectively. The production cost with the proposed indirect‐constant HDH system is equal to 0.56 $/m3 of freshwater. [ABSTRACT FROM AUTHOR]

Because of the lack of good seedling positioning during vegetable grafting, there are issues such as high labor costs and long grafting time. This article proposes a negative pressure suction seedling positioning method for seed leaves based on the characteristic parameters of cucumber spike wood, and designs a flexible adsorption positioning mechanism for spike wood. Firstly, the ventral surface curve trajectories of cucumber cotyledons were extracted using Matlab software, and then a shape-adaptive design was applied to the attachment surface of the flexible suction positioning mechanism, and a computational fluid dynamics model of the airflow field was established. By combining Fluent simulation analysis with orthogonal experiments, the effect of suction hole diameter, vacuum negative pressure value, suction hole quantity, and suction hole depth on the adsorption effect of the suction head was analyzed, the main and secondary factors and operational indicators that affect the adsorption effect are evaluated. The optimal parameter combination: suction hole diameter of 1.5 mm, vacuum negative pressure value of 2 kPa, suction hole quantity of 42, and suction hole depth of 2 mm, has been found. A verification experiment was conducted on a test bench, and the experimental results show that the success rate of leaf absorption using the optimal parameter combination is 97.69%, which indicates that the suction head is designed reasonably and meets the requirements of grafting. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is an airway disease caused by periodic collapse of the airway during sleep. Imaging-based subject-specific computational fluid dynamics (CFD) simulations allow non-invasive assessment of clinically relevant metrics such as total pressure loss (TPL) in patients with OSA. However, most of such studies use static airway geometries, which neglect physiological airway motion. This study aims to quantify how much the airway moves during the respiratory cycle, and to determine how much this motion affects CFD pressure loss predictions. Motion of the airway wall was quantified using cine MRI data captured over a single respiratory cycle in three subjects with OSA. Synchronously-measured respiratory airflow was used as the flow boundary condition for all simulations. Simulations were performed for full respiratory cycles with 5 different wall boundary conditions: (1) a moving airway wall, and static airway walls at (2) peak inhalation, (3) end inhalation, (4) peak exhalation, and (5) end exhalation. Geometric analysis exposed significant local airway cross-sectional area (CSA) variability, with local CSA varying as much as 300%. The comparative CFD simulations revealed the discrepancies between dynamic and static wall simulations are subject-specific, with TPL differing by up to 400% between static and dynamic simulations. There is no consistent pattern to which static wall CFD simulations overestimate or underestimate the airway TPL. This variability underscores the complexity of accurately modeling airway physiology and the importance of considering dynamic anatomical factors to predict realistic respiratory airflow dynamics in patients with OSA. [ABSTRACT FROM AUTHOR]

Metallic microfluidic devices made from powder-bed additive manufacturing systems have received increasing attention, but their feasible channel geometry and complexity are often limited by lack of an effective approach to removing trapped powder particles within the channels or conduits of the sintered parts. Here, we present an innovative approach to fabricating long serpentine, high-aspect-ratio submillimeter channels made of stainless steel 316L (SS) by binder jet printing (BJP) and liquid-phase sintering. We leverage the unique nature of the BJP process, that is printing and consolidation steps are decoupled, enabling us to join two or more parts during the sintering step. Instead of constructing the channel device as a single part, we print multiple parts for easy powder removal and later join them to form enclosed channels. The key innovation lies in adding sintering additives like boron nitrides (BN) to the SS stock powder—at the SS/BN interfaces, liquid phase is locally generated at temperature much lower than the SS melting temperature, facilitating the bonding of the multiple parts as well as the consolidation of parts for near-full density. We systematically vary the sintering temperature to show how it affects the joining quality and the channel shape distortion. The joining quality such as the fracture strengths of the joined samples is measured by a pull test while the shape distortion is characterized by various imaging techniques. The feasibility of the proposed approach is demonstrated by fabricating a 400-mm-long, fully enclosed serpentine channel with a rectangular cross-section of 0.5 mm in width and 1.8 mm in height. The pressure drop across this 3D-printed SS serpentine channels is measured for air flow and compared to a standard gas flow model, showing that the device is free of leakage or clogs. [ABSTRACT FROM AUTHOR]

The air humidification-dehumidification (HDH) technique for water desalination can be useful in many water production applications. Researchers from all around the world have examined various implementations of this technology to improve it. The present research investigates the effect of three dehumidifier coolants on the system. These coolants include water, helium, and hydrogen. The impact of these coolants on the parameters of the humidification-dehumidification desalination system will be discussed. The investigation's parameters are tested at various mass ratios, air flow rates, and air outlet heaters. The results show that when hydrogen is employed as a dehumidifier coolant, the gained output ratio (GOR) achieves its peak of 6.37 in the considered mass ratio range of 2.1 to 3. On the other hand, when hydrogen is utilized as a dehumidifier coolant, the system produces the maximum entropy, with the dehumidifier contributing the most. When the mass ratio changes from 2 to 3, the average entropy generation for the system using hydrogen in the dehumidifier increases by 3.8 and 2.9 times, respectively, compared to the average entropy generation for the system using water and helium. However, when hydrogen is used as a dehumidifier coolant, safety concerns must be addressed, as well as the size and cost of heat exchangers in comparison to water. [ABSTRACT FROM AUTHOR]

This work presents a novel approach to investigating the slip effect in nanofiber filter media. Electrospun nanofiber media with high efficiency and low pressure drop were produced at different concentrations and durations. The surface and cross-sectional morphology of nanofiber media were studied using FE-SEM. Fiber orientation and diameter distributions were also examined. The 3D virtual nanofiber media was modeled using this information along with the experimentally measured porosity and thickness of the media. The effect of the slip phenomenon in nanofiber media was studied numerically, and the results were compared to experimental data. Excellent agreements were found between the measured and simulation results. Additionally, filtration simulations considering aerosols injected with airflow through the nanofibrous filter media were conducted by considering the slip effect, and the effect of filter structure on filtration performance (removal efficiency and pressure drop) was investigated. [ABSTRACT FROM AUTHOR]

Background: Obstructive sleep apnea (OSA) is a prevalent sleep breathing disorder affecting 9–25% of the general adult population. Aim: To assess airflow limitation by spirometric indices in patients with obstructive sleep apnea. Patients and methods: This observational case–control study was conducted on 60 subjects who were divided into four groups: Group I (control group), included 20 subjects chosen from other departments, who had no respiratory complaints with apnea–hypopnea index (AHI < 5); Group II (mild group), included 11 patients with mild sleep apnea, 5 ≤ AHI < 15; Group III (moderate group), included 17 patients with moderate sleep apnea, 15 ≤ AHI < 30; and Group IV (severe group), included 12 patients with severe sleep apnea, AHI ≥ 30 at the Chest Department, Faculty of Medicine, Helwan University, from August 2021 until June 2022. Results: There was no statistically significant relation found between the severity of AHI and all the previous pulmonary function parameters except a statistically significant decrease in FEF (25–75%) in the moderate group than the mild group and also in the severe group than the moderate group (p-value < 0.001). There was a statistically significant positive correlation found between AHI and BMI and NC and a negative correlation found between AHI and FEF (25–75%) while no statistically significant correlation was found between AHI and the other studied parameters. Conclusion: Obstructive sleep apnea (OSA) is associated with airflow limitation by spirometric indices, although this association is statistically insignificant. On the other hand, the severity of obstructive sleep apnea is directly proportional to the seriousness of the apnea–hypopnea index (AHI). Strong correlations were found between the severity of AHI and body mass index (BMI), neck circumference, and FEF (25–75%). [ABSTRACT FROM AUTHOR]

In engineering phase-change phenomena are found in a multitude of applications, ranging from refrigeration and air conditioning to steam turbines and petroleum refining. This study investigates the flow of moist air in a circular duct where water vapour condenses in contact with the cold wall of the duct. The investigation delves into the relationship between the condensation mass transfer rate, the heat transfer between the bulk flow and the wall, and the temperature of the wall. The volume of fluid model coupled with the Lee evaporation-condensation model was employed. Five simulations were carried out, involving different wall temperatures while maintaining the same inlet conditions. Condensation was more pronounced at lower wall temperatures, which aligns with the expectations. The heat transfer between the bulk flow and the wall decreased with the decreasing temperature difference. Interestingly, the findings revealed that the surface heat transfer coefficient increased as the wall temperature approached the temperature of the bulk flow. The success of the study suggests potential applications in optimising thermal management systems, with implications for industries where accurate predictions of moisture behaviour and heat transfer are crucial. [ABSTRACT FROM AUTHOR]

Drying and sanitising equipment has been very common in industrial plants since the pandemic. These are devices that consume significant amounts of energy. The best solution is to use a drying chamber equipped with a heat pump, which allows partial recovery of the energy. In the design of the drying chamber, the drying time is important, which depends both on the parameters of the heat pump itself, and the geometry and airflow of the drying chamber. The geometry and airflow supply should be arranged to ensure a uniform distribution of velocity throughout the drying area. For this purpose, the use of CFD simulations has been proposed. A model was developed in ANSYS/FLUENT where all model parameters, including the optimal mesh density, turbulence models, etc., were determined. The model was verified on the experimental results of the basic design of the chamber. Then an innovative design was proposed that was modelled and optimised in terms of the distribution of the inlet's perforation. The final design was made, and, at the same time, the simulation's results were verified by measuring the velocity of airflow in the new design. Together with the optimisation of the heat pump, this made it possible to reduce the drying time by 50%, with a simultaneous reduction in the energy consumed. [ABSTRACT FROM AUTHOR]

The disorder and disaster evolution characteristics of ascensional airflow fires in mine ventilation systems has been the focus of mine fire research. In this work, through repeated experiments, the variation characteristics of the temperature and air volume in the main and side branches of an ascensional airflow fire were obtained under different ventilation capacities. Using the TF1M(3D) software to solve the problems of mine physical ventilation and combined with the analysis of an example, the variation in the ascensional airflow fire and the process of disordered airflow in the ventilation system in an entire area mine were described in detail. Fire combustion served as the power source for uncontrolled energy release, and its fire pressure interacted with the thermal resistance of the mine ventilation, directly causing airflow disorder. As the fire intensified, the ascensional airflow fire caused the airflow in the side branch to decrease, stagnate, or reverse. Improving the fan supply capacity can not only help reduce the increase in the ventilation thermal resistance of the side branch but also help avoid the airflow reversal of the side branch. From the regular variation characteristics, the theoretical results were found to be in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

The control of oxygen and carbon dioxide concentrations in an airflow released from a reactor, in which a sample is heated, can be used to investigate the thermal stability of polymer materials. This approach, known as oxithermography, involves analyzing experimental data (oxithermograms), representing the variation in oxygen concentration decrease and carbon dioxide appearance in an airflow with changing temperature conditions. This method allows for monitoring the effect of fillers introduced into polymer compositions on their thermal stability. The application of oxithermography to studying oxidative thermostability is demonstrated using pure polypropylene and polypropylene with titanium dioxide admixtures as examples. [ABSTRACT FROM AUTHOR]

To attain high-performance ejector configurations, an ejection characteristic testing system was established initially to validate the reliability of the Realizable k-εturbulent model. Subsequently, optimization investigations were conducted on lobed nozzle ejectors with various structural parameters. The effects of four key structural parameters, including lobed nozzle expansion angle α, lobed nozzle width d, number of lobes in the nozzle n, and height of the square-to-circle section h, were systematically studied. Furthermore, the CRITIC method was employed for multi objective evaluation to identify the optimal design configuration for the casing ejector. The research findings revealed that among the structural parameters, the lobed nozzle expansion angle α exerted the greatest influence on the ejection coefficient and pressure loss coefficient. The weights of the evaluation criteria were determined by the CRITIC method as follows: ejection coefficient (49.38%) < pressure loss coefficient (50.62%). The optimal design configuration determined by the CRITIC method included α = 45°, d = 150 mm, n = 14, and h = 600 mm. The resulting enclosure design ensures smooth airflow within the system, preventing the backflow of high temperature mainstream fluid and heating the enclosure. It also maintains a temperature distribution in the typical cross-section that meets specified requirements. Additionally, it facilitates improved mixing of mainstream and secondary fluid and reduces exhaust gas temperature. [ABSTRACT FROM AUTHOR]

Based on the mean sea level pressure field and 10-meter wind field across eastern China, weather patterns were classified using principal component analysis in the T-model (T-PCA), and four weather conditions were identified. Weather conditions and meteorological factors affecting the winter PM2.5 concentration in the Beijing–Tianjin–Hebei (BTH) region and the Yangtze River Delta (YRD) were also analyzed. The results showed that there were significant differences in the PM2.5 distribution between BTH and the YRD under different weather conditions. The intensity and path of cold air played important roles in regulating the PM2.5 concentration distribution in eastern China. For the BTH region, under type 2 and type 4 conditions, the weather was stable, and heavy pollution frequently occurred; however, under type 1 and type 3 conditions, cold air was active, and the air quality improved. For the YRD, both type 1 and type 4 conditions lead to high PM2.5 concentrations in this region. Type 1 cold air flows southward along the northwestern path and is beneficial for transporting pollutants from BTH to the YRD, causing a high probability of PM2.5 pollution. Conversely, the southward movement of type 3 cold air along the eastern path was beneficial for pollutant diffusion in the YRD. [ABSTRACT FROM AUTHOR]

To design and operate various equipment of the solids control system in offshore drilling platforms, it is important to establish how the moisture content influences the characteristics of drilled cuttings to form packed beds and flow over solid surfaces. The current study comprehensively analyzes how moisture content, primarily composed of water and representing waterbased muds (WBMs), influences the bed packing properties and drilled cuttings' flowability. The particle aggregation/disaggregation dynamics, loose and tapped bulk densities and porosities, compaction dynamics of packed beds, Hausner ratio, and angle of repose of drilled cuttings with ten distinct moisture contents (1.4--44.0 wt%) were analyzed. It was noticed that the increment of moisture content up to 15.2% promoted the formation of looser interparticle structures. However, these structures were steadier, showing greater difficulty flowing and releasing air/liquid. The continuous increment of moisture content beyond 15.2% promoted a complete change in the material behavior. The interparticle structures became denser. The material could flow and release air/liquid more easily. In addition, it was possible to establish a classification of the different behaviors of drilled cuttings according to the moisture content. Predictive models were proposed to describe the influence of the moisture content on the bed packing and flowability properties of drilled cuttings. [ABSTRACT FROM AUTHOR]

Coronaviruses being capable of spreading through droplet contamination have raised significant concerns regarding high-capacity public rail transport, such as the metro. Within a rapidly moving railcar cabin, the internal airflow lags behind the bulkhead, generating internally induced airflow that accelerates droplet dispersion within a non-inertial reference system. This study investigates the impact of acceleration on the diffusion of cough droplets of varying sizes using computational fluid dynamics. The modified k–ε equation in ANSYS® Fluent was utilized to simulate droplet diffusion under different body orientations by adjusting the inertial force correction source term. Results indicate that droplets in the middle size range (50–175 μm) are primarily influenced by inertial forces, whereas smaller droplets (3.5–20 μm) are predominantly controlled by air drag forces. Regardless of facial orientation, the outlet of high-capacity public rail transport poses the highest risk of infection. [ABSTRACT FROM AUTHOR]

The energy reduction in chillers has been considered an important factor in the energy efficiency improvements of cooling systems, and water-side free cooling is regarded as the key of chiller free cooling technology. Therefore, this research aims to develop a control methodology for the extension of the free cooling operation time in order to improve the efficiency of water cooling-type chillers based on a WSE (water-side economizer) system for a data center and review the proper control conditions through an energy usage analysis of the entire system. The suggested methodology is an increase in the chilled water supply and return temperature according to the increase in the CARH (Computer Room Air Handler) fan air flow and a decrease in the chilled water flow. A case study was conducted according to the application of control through an EnergyPlus simulation. The results of the simulation show that energy usage was reduced by 8.1% under 120% CRAH fan capacity and 100% chilled water flow conditions. When applying the control plan, the free cooling period was extended according to the increased CRAH fan capacity and decreased chilled water flow. However, the increase in the CRAH fan energy must be considered. Also, in the case of a reduction in the chilled water flow, it is necessary to consider a point that can guarantee the cooling treatment heat rate in the heat exchanger. [ABSTRACT FROM AUTHOR]

When the lightweight quartz fiber-reinforced phenolic (LQFRP) composite is subjected to the combined effect of a local structural heat source and high-speed airflow, its ablation behavior exhibits significant localized characteristics and strong coupled effect. In this study, we have developed a bidirectional loosely coupled numerical model that integrates thermal, fluid, solid and ablation phenomena to solve the ablation-through problem of the LQFRP composite. The model takes into account the mechanisms of pyrolysis, oxidation, sublimation, and thermal mechanical erosion that occur during the ablation process of the LQFRP composite. The results suggest that the local structural heat source plays a crucial role in the erosion and retreat of the LQFRP composite. The morphology of the ablation pit shows a noticeable asymmetry, which is attributed to the aerodynamic heat and force. As a result of the local structural heat source, the fluid temperature downstream of the ablation pit is higher compared to that upstream of the ablation pit. The fluid that flows downstream of the ablation pit undergoes significant compression, leading to the formation of an oblique shock wave. The distribution of resin pyrolysis degree within the LQFRP composite is influenced by internal heat conduction. This study will offer valuable insights and guidance for the practical application of the LQFRP composite in the ultra-high temperature field. [ABSTRACT FROM AUTHOR]

Unilateral cleft lip and palate (UCLP) nasal deformity impacts airflow patterns and pressure distribution, leading to nasal breathing difficulties. This study aims to create an integrated approach using computer-aided design (CAD) and computational fluid dynamics (CFD) to simulate airway function and assess outcomes in nasal deformities associated with unilateral cleft lip and palate (UCLP) after LeFort I osteotomy advancement. Significant alterations were observed in nasal geometry, airflow velocity, pressure dynamics, volumetric flow rate, and nasal resistance postoperatively, indicating improved nasal airflow. The cross-sectional area increased by 26.6%, airflow rate by 6.53%, and nasal resistance decreased by 6.23%. The study offers quantitative insights into the functional impacts of such surgical interventions, contributing to a deeper understanding of UCLP nasal deformity treatment and providing objective metrics for assessing surgical outcome. [ABSTRACT FROM AUTHOR]

The archerfish is unique in its ability to hunt by shooting a jet of water from its mouth that hits insects situated above the water's surface. To aim accurately, the fish needs to overcome physical factors including changes in light refraction at the air-water interface. Nevertheless, archerfish can still hit the target with a high success rate under changing conditions. One possible explanation for this extraordinary ability is that it is learned by trial and error through a motor adaptation process. We tested this possibility by characterizing the ability of the archerfish to adapt to perturbations in the environment to make appropriate adjustments to its shots. We introduced a perturbing airflow above the water tank of the archerfish trained to shoot at a target. For each trial shot, we measured the error, i.e., the distance between the center of the target and the center of the water jet produced by the fish. Immediately after the airflow perturbation, there was an increase in shot error. Then, over the course of several trials, the error was reduced and eventually plateaued. After the removal of the perturbation, there was an aftereffect, where the error was in the opposite direction but washed out after several trials. These results indicate that archerfish can adapt to the airflow perturbation. Testing the fish with two opposite airflow directions indicated that adaptation took place within an egocentric frame of reference. These results thus suggest that the archerfish is capable of motor adaptation, as indicated by data showing that the fish produced motor commands that anticipated the perturbation. [ABSTRACT FROM AUTHOR]

The airport line plays an important role in the airport landside traffic connection, which greatly relieves the urban road pressure. Studying the characteristics and laws of the time and space distribution of the airport line passenger flow will provide basic support for the airport line's capacity configuration, passenger flow control, and air‐track coordinated operation, and will also provide quantitative basis for the layout of urban terminal buildings. This paper proposes a method to analyse the temporal and spatial distribution characteristics of airport line passenger flow based on AFC card swiping data. By mining and extracting the travel behaviour data of subway airport line air passengers, the distribution characteristics of airport line passenger flow are analysed and visualized from two aspects of passenger travel time and space. Finally, a case study is carried out based on the actual data of Daxing airport express. The results show that: (1) the travel time of departure and return passengers is concentrated in 60–90 min; (2) The departure and arrival points of passengers are concentrated within the Fourth Ring Road, and a large number of air passenger flows are gathered and evacuated at hubs such as Beijing South Railway Station and Beijing West Railway Station. [ABSTRACT FROM AUTHOR]

An air-based photovoltaic thermal collector (PVTC) is a system that generates both electricity and heat using air flowing over a photovoltaic (PV) module. This system offers the advantage of easy maintenance; however, it suffers from lower thermal efficiency compared to other PVTCs, mostly owing to the low heat capacity of air. Thus, this study introduces a novel PVTC incorporating dual ducts and semicircular turbulators, which were experimentally evaluated under actual weather conditions in the Republic of Korea. The proposed PVTC was compared with two other types of PVTC: one is a single-duct PVTC with semicircular turbulators, and the other is a dual-duct PVTC without turbulators. The results showed that the thermal efficiency of the proposed PVTC increased by approximately 88.7% compared to the single-duct PVTC with a turbulator and by 9.3% compared to the dual-duct PVTC without a turbulator. The electrical efficiency showed a slight decrease of about 7.2% compared to the single-duct PVTC but an increase of 1.4% compared to the dual-duct PVTC without a turbulator. Overall, the total efficiency of the proposed PVTC increased by 54.2% and 7.7% compared to the single-duct PVTC and the dual-duct PVTC without a turbulator, respectively. These experimental results demonstrate that attaching dual ducts and semicircular turbulators to an existing PVTC increases the daily thermal energy output, which ultimately enhances the total daily energy output. [ABSTRACT FROM AUTHOR]

Achieving a quick temperature increase is a burning issue for biophysical applications, like germ inactivation and tumor ablation, and for energy performances, like solar collectors and steam generators. Based on the plasmon resonance phenomenon, noble metallic nanoparticles have emerged as promising weapons due to their very high biocompatibility, optical properties, and high surface-to-volume ratio, increasing energy conversion and allowing the maximum temperature to be reached faster. This work examines the energy conversion in sandwiched glassy platforms with gold nanorods. The platforms are kept vertically in the air and illuminated by a 0.5 W near-infrared laser (808 nm). To describe this aspect theoretically, the size and conversion efficiency of the electromagnetic properties are compromised between the proposed model and the stability of the nanorods. As a research approach, our model of cross-sections and polarizability for the surface effect is proposed, coupled with classical CFD numerical calculations. The results of the proposed model, validated by a thermal camera and spectroscopy measurements, indicate that as long as the energy conversion is visible with relatively low-power lasers (ΔT = 18.5 °C), the platforms do not offer fast heat dissipation. The results indicate that, despite the flow forcing by the air inflow, the entropy generation due to heat conduction is more than three orders higher than the dynamic entropy production. Flow forcing corresponds to the value of the velocity for classical convective motions. Therefore, the delivered heat flux must be distributed via convective transport or the associated high-conductive materials. [ABSTRACT FROM AUTHOR]