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In this paper, we consider the problem of numerical investigation of the counting statistics for a class of one-dimensional systems. Importance sampling, the cornerstone technique usually implemented for such problems, critically hinges on selecting an appropriate biased distribution. While an exponential tilt in the observable stands as the conventional choice for various problems, its efficiency in the context of counting statistics may be significantly hindered by the genuine discreteness of the observable. To address this challenge, we propose an alternative strategy, which we call importance sampling with the local tilt. We demonstrate the efficiency of the proposed approach through the analysis of three prototypical examples: a set of independent Gaussian random variables, Dyson gas, and symmetric simple exclusion process with a steplike initial condition. [ABSTRACT FROM AUTHOR]

A precise description of the thermodynamic states of gaseous and solid detonation products is essential when using thermodynamic calculations to determine the detonation performance and destructive power of explosives. For high oxygen-lean explosives (the oxygen contained in explosives is insufficient to completely oxidize combustible elements and excess solid carbon will be generated in the detonation products), the phase state of solid carbon product affects the Chapman–Jouguet (CJ) detonation performance parameters, reaction zone, and energy release process. However, the recovery of detonation products demonstrates that the actual detonation carbon product is primarily a mixed state of diamond/graphite stack, as opposed to the existing thermodynamic codes, which essentially treat detonation carbon as single-phase carbon. To understand the thermodynamic effect of the mixed carbon phase state on the non-ideal detonation behavior, in this work, the matching relationship among the VINET equation of state parameters, thermodynamic potential parameters of the solid products of the equivalent system and the phase mixed system was constructed by using the nonlinear fitting method. The relationship between the carbon phase composition at the CJ point and the explosive composition structure was researched. Investigations were conducted into how the mixed carbon phase affected the volume and content of gas products as well as the composition at CJ points. Diamond formation in products is good for enhancing explosive's working capacity. Based on mixed-state potential parameters, the correlation mechanism between the mixed carbon phase and the chemical reaction zone was investigated, and it was found that intramolecular carbon/intermolecular carbon and more detonation graphite/diamond products all would lead to the extension of the reaction zone. [ABSTRACT FROM AUTHOR]

Defect generation and recovery at the interface of a silicon dioxide/silicon ( SiO 2 /Si) stack are studied in oxygen ( O 2) or argon (Ar) plasma processing and post-annealing. Defect generation is recognized to be dependent on the processing gas and the SiO 2 layer thickness. O 2 plasma processing shows a strong incident-ion energy dependence, where ion's implantation, diffusion, and reactions in the SiO 2 layer play important roles in defect generation. A similar dependence is observed for Ar plasma processing; however, it also shows the photon effects in defect generation for a thick SiO 2 layer. Defect recovery is demonstrated by annealing, where recovery depends on the annealing temperature as well as the amount of defects generated at the interface. [ABSTRACT FROM AUTHOR]

This article employs fluid equations to analyze muon beams in gases subject to crossed electric and magnetic fields, focusing, in particular, on a scheme proposed by Taqqu [Phys. Rev. Lett. 97, 194801 (2006)], whereby transverse compression of the beam is achieved by creating a density gradient in the gas. A general criterion for maximizing beam compression, derived from first principles, is then applied to determine optimal experimental conditions for μ+ in helium gas. Although the calculations require the input of transport data for (μ+, He), which are generally unavailable, this issue is circumvented by "aliasing" (μ+, He) with (H+, He), for which transport coefficient data are available. [ABSTRACT FROM AUTHOR]

The present study reveals the effects of symmetry on how the distribution and flow of energy play out on the decomposition of small halocarbons. Unimolecular decay of the freons CHFCl2 and CF2Cl2 when ionized has been investigated. Mass spectrometric results that encompass isotope effects (peak heights) and energy distribution in the exit channel (peak shapes) are interpreted by computational methods. Non-statistical processes of electronic predissociation and isolated state decay are shown to be directly associated with molecular symmetry. [ABSTRACT FROM AUTHOR]

We consider the interaction problem of a steepened wave with a strong shock in the planar and radially symmetric flow of a van der Waals stiffened relaxing gases. An exact solution to the considered system is used to investigate the evolution of a steepened wave. The significance of van der Waals excluded volume, density, and velocity of solid crystals on a steepened wave is determined. Attention is drawn to analyzing the interaction between steepened wave and blast wave. The amplitudes of reflected and transmitted waves along with the bounce in shock acceleration, originating from collision between steepened wave and strong shock, are also computed. [ABSTRACT FROM AUTHOR]

In this computational study, we describe a self-consistent trajectory simulation approach to capture the effect of neutral gas pressure on ion–ion mutual neutralization (MN) reactions. The electron transfer probability estimated using Landau–Zener (LZ) transition state theory is incorporated into classical trajectory simulations to elicit predictions of MN cross sections in vacuum and rate constants at finite neutral gas pressures. Electronic structure calculations with multireference configuration interaction and large correlation consistent basis sets are used to derive inputs to the LZ theory. The key advance of our trajectory simulation approach is the inclusion of the effect of ion-neutral interactions on MN using a Langevin representation of the effect of background gas on ion transport. For H+ − H− and Li+ − H(D)−, our approach quantitatively agrees with measured speed-dependent cross sections for up to ∼105 m/s. For the ion pair Ne+ − Cl−, our predictions of the MN rate constant at ∼1 Torr are a factor of ∼2 to 3 higher than the experimentally measured value. Similarly, for Xe+ − F− in the pressure range of ∼20 000–80 000 Pa, our predictions of the MN rate constant are ∼20% lower but are in excellent qualitative agreement with experimental data. The paradigm of using trajectory simulations to self-consistently capture the effect of gas pressure on MN reactions advanced here provides avenues for the inclusion of additional nonclassical effects in future work. [ABSTRACT FROM AUTHOR]

We report that the gas components in the N59 bubble suffered from sequential multiple cloud–cloud collision (CCC) processes. The molecular gas in the N59 bubble can be decomposed into four velocity components, namely Cloud A [95, 108] km s |$^{-1}$|⁠ , Cloud B [86, 95] km s |$^{-1}$|⁠ , Cloud C [79, 86] km s |$^{-1}$|⁠ , and Cloud D [65, 79] km s |$^{-1}$|⁠. Four CCC processes occurred among these four velocity components, i.e. Cloud A versus Cloud B, Cloud A versus Cloud C, Cloud C versus Cloud D, and Cloud A versus Cloud D. Using the near- and mid-infrared photometric point source catalogues, we identified 514 young stellar object (YSO) candidates clustered in 13 YSO groups, and most of them (⁠|$\sim 60~{{\ \rm per\ cent}}$|⁠) were located at the colliding interfaces, indicating that they were mainly triggered by these four CCC processes. We also found that these four collisions occurred in a time sequential order: the earliest and most violent collision occurred between Cloud A and Cloud D about 2 Myr ago, then Cloud B collided with Cloud A about 1 Myr ago, and finally, Cloud C collided with Clouds A and D simultaneously about 0.4 Myr ago. [ABSTRACT FROM AUTHOR]

Our aim in this study is to investigate the electronic structure of the gaseous YN molecule and provide an accurate molecular line list of spectroscopic transitions between the five lowest singlet states. The calculations were done by using large basis set for yttrium aug-cc-pVQZ-PP with relativistic effective core potentials at the spin-free level. We first used the method of complete active space self-consistent field, which was followed by the multireference singles and doubles configuration interaction. Potential energy curves and permanent and transition dipole moments were calculated at the internuclear distance range of 1.3–2.96 Å. For each state, we calculated the spectroscopic constants (T e, ω e, ω e x e, ω e y e, B e, α e, R e). The calculated values of the spectroscopic constants are in excellent agreement with the experimental constants available, with a relative difference of less than 5 cm−1. We further calculated the transition intensities of allowed transitions, and we provided the absorption spectra up to a temperature of 4000 K. The computed molecular line list contains 2.6 million transitions calculated between almost 18 186 vibro-rotational energy levels. It covers the frequency range between 0 and 30 000 cm−1. The effect of temperature on the spectra of hot YN was investigated with partition functions calculated between 298 and 4000 K. This study should help in identifying the singlet state spectrum of the hot YN molecule, which is possibly found in the atmospheres of cool stars and hot rocky super-Earths. [ABSTRACT FROM AUTHOR]

Antibubbles are liquid droplets encapsulated by a gas film that have recently been explored for on-demand ultrasound-triggered drug release. However, their ultrasound imaging capabilities are limited by their stiff shells stabilized with silica nanoparticles. Here, we develop polymeric antibubbles that generate greater ultrasound contrast than silica-based antibubbles, while showing better stability than conventional polymeric microbubbles. [ABSTRACT FROM AUTHOR]

We consider a dissipative Baer-Nunziato type system for a mixture of two compressible heat conducting gases in the whole space. The existence theory of the global solution to the system is established in H N (R 3) -framework (N ≥ 2) when only the H 2 -norm of the initial perturbation is small. The weighted energy method combined with the low-frequency and high-frequency decomposition is used to derive the desired a priori estimates and hence the global existence. As a by-product, we obtain the decay rates of spatial derivatives of the solution. [ABSTRACT FROM AUTHOR]

A catalyst-free method was developed for the ring opening of azlactones (also known as oxazolones) in water microdroplets. Azlactone was dissolved in a water : acetonitrile (1 : 1) mixture, and the solution is sprayed by using nitrogen gas at a pressure of 120 psi to generate microdroplets. This method promoted selective cleavage of the lactone bond to afford the corresponding N-benzoyl derivatives in up to 94% isolated yield with no epimerization. Our method produces the ring-opening products in milliseconds (up to 94 μmol for 33.3 minutes), and may have utility for high-throughput synthesis applications. [ABSTRACT FROM AUTHOR]

This research integrates context-based learning and modelling. It presents a teaching-learning sequence (TLS) about the dissolution of gases in liquids using carbonated drinks as the context. The impact of the TLS is analysed in a longitudinal short-term study involving two groups of learners aged 13–14 years old (n=53). The results led us to infer five models explaining how carbon dioxide is distributed in a carbonated soft drink, categorized and ordered by increasing complexity as follows: Gas apart; Bubbles; Bubbles and something else; Dissolved gas; and Oversaturation. Some of these models reflected preconceived ideas based on students' personal experience, while others emerged from the teaching. Three clusters of students were identified based on the frequency with which their responses were included in the models Dissolved gas or Oversaturation. Overall, the TLS shows potential as a framework for enhancing students' knowledge. This is reflected in the fact that more advanced models of dissolution became increasingly identifiable in their responses as they worked through the activities, while less sophisticated ones were observed less frequently. Overall, nearly two-thirds of them demonstrated that they had acquired an understanding of the concept of dissolved gas. Some of the activities used seem to be particularly helpful in this respect. [ABSTRACT FROM AUTHOR]

This paper is concerned with the analytical construction of piecewise smooth solutions containing a single shock wave for the radially symmetric relativistic Euler equations with polytropic gases. We derive meticulously the a prioriC1$C^1$‐estimates on the Riemann invariants of the governing system under some assumptions on the piecewise initial data. Based on these estimates, we show that the long time of existence of smooth solutions in the angular region bounded by a characteristic curve and a shock curve. The piecewise smooth initial conditions ensured the existence of smooth solutions in the angular region are discussed. Moreover, it is verified that the existence time is proportional to the initial discontinuous position. [ABSTRACT FROM AUTHOR]

The exact solutions for the Navier–Stokes–Fourier equations in the case of plane shock waves for dilute monatomic gases with constant transport coefficients were found by Becker in 1922. The solutions obtained are limited for a Prandtl's number given by Pr=3/4$Pr=3/4$. Besides the solutions for the speed and temperature, profiles were given in an implicit way. In this paper, we consider Becker's model to find some exact explicit solutions for dilute polyatomic gases. [ABSTRACT FROM AUTHOR]

We study the formation of singularities of smooth solutions to the relativistic Euler equations of Chaplygin gases in Schwarzschild spacetime. The system is in the spherically symmetric form, and its coefficients and nonhomogeneous terms contain a parameter reflecting the mass of the black hole, which makes it highly nonlinear and complicated. To overcome the influence of the mass parameter of black hole, we introduce a pair of suitable auxiliary variables related to it and derive their characteristic decompositions to establish the estimates of the smooth solution. We show that, for a kind of initial data, the smooth solution develops singularity in finite time and the mass‐energy density itself approaches infinity at the blowup point. [ABSTRACT FROM AUTHOR]

Radon can move freely through air and water. Water radon measurement is a method of earthquake monitoring and water radon can be used as an environmental tracer to follow transit pathways. A novel bubbling device was developed for continuous detection of waterborne radon levels. Equilibrium between water and gas-phase radon concentrations in the gas path of this device is attained through circulation and bubbling. Monitoring gas radon allows dynamic tracking of water radon concentration. At the temperature of 22.6 °C, the device exhibits a sensitivity of 0.0016 CPM/Bq/m3 and detects concentrations within the range of 0.96–180,000 Bq/m3. [ABSTRACT FROM AUTHOR]

This study developed predictable exposure scenarios for thorium-containing gas mantles throughout their life cycle, considering their usage status in the Republic of Korea, and assessed the radiation dose for each scenario. Our results showed that radiation doses in various scenarios, including transport, distribution, usage, and disposal, as well as in low-probability accident scenarios, consistently remained below the regulatory exemption standards set by the International Atomic Energy Agency. Therefore, we concluded that the exemption regulation for the gas mantle is valid under current circumstances in the ROK. [ABSTRACT FROM AUTHOR]

The article is the second in a three-part series that explores the causes and contributing factors of the Bhopal gas tragedy. Topics include the role of equipment failures in impacting safety system performance, the comparison between actual safeguard performance at the Bhopal factory and its designed expectations, and the hazard identification and risk analysis (HIRA) approach used to assess the effectiveness of safeguards in chemical plants.

In this study, a new comprehensive fully coupled elastic-hydrodynamic model is developed for a multi-layer gas foil thrust bearing (GFTB). The interaction effects among the top foil, back board, middle foil, and bottom foil, as well as the Coulomb friction effect, are considered. The stiffness and static characteristics obtained by the experimental and theoretical approaches are in good agreement, which verifies the accuracy of the model. The contribution of each foil layer to the overall stiffness and the load-carrying mechanism are analyzed. Interaction effects of the load, preload, and rotational speed on the static performance are investigated comprehensively. Furthermore, start-stop tests are performed to achieve the lift-off speed, start-up torque, and shut-down torque under various operating conditions. [ABSTRACT FROM AUTHOR]

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In this paper, a CFD model is developed to examine the stratification characteristics of hydrogen-blended natural gas in residential gas risers. Meanwhile, the accuracy of the CFD model is validated by field experiments. The effects of relevant parameters on stratification are analyzed, including hydrogen blending ratio, riser internal diameter, riser height, media temperature, and media pressure. The relative importance of relevant parameters for stratification is identified using the orthogonal experiment design and improved grey relational analysis. Furthermore, a device is designed to mitigate the impact of blended gas stratification. The results show that the stratification of hydrogen-blended natural gas inside residential gas risers is significant in the direction of gravity. The maximum stratification height in standing for 8 h can reach up to 17.4 cm. The stratification height presents a negative correlation with riser internal diameter, riser height, and media temperature, while that represents a positive correlation with hydrogen blending ratio and media pressure. Furthermore, the effects of these parameters on stratification height could be ranked as follows: media pressure > hydrogen blending ratio > riser internal diameter > riser height > media temperature. These achievements provide effective guidance for residential users on safely using hydrogen-blended natural gas. [ABSTRACT FROM AUTHOR]

In this work, the ZnO microsphere is prepared by hydrothermal method and modified with different concentrations of Eu. The morphology of ZnO:Eu sample shows flower-like microspheres with many nanosheets. The gas performance of ZnO:Eu microsphere is investigated for detecting NO 2. Compared with pure ZnO, the response of ZnO:2 % Eu sensor is increased by 8 times, and the optimal operating temperature of that is decreased to 130 °C. Especially, the gas sensing properties of ZnO:2 % Eu sensor is enhanced under UV excitation. The recovery time of ZnO:Eu sensor is reduced by 1200 s, and the response is increased by 3.6 times under UV excitation. The above results show an increase in sensor response due to doping Eu and UV excitation. At last, the possible gas mechanism of ZnO:Eu is discussed with and without UV excitation. This finding provides important guidance for UV-assisted sensors to enhance NO 2 response. [ABSTRACT FROM AUTHOR]

Polaron, a typical quasi-particle that describes a single impurity dressed with surrounding environment, serves as an ideal platform for bridging few- and many-body physics. In particular, different few-body correlations can compete with each other and lead to many intriguing phenomena. In this work, we review the recent progresses made in understanding few-body correlation effects in attractive Fermi polarons of ultracold gases. By adopting a unified variational ansatz that incorporates different few-body correlations in a single framework, we will discuss their competing effects in Fermi polarons when the impurity and majority fermions have the same or different masses. For the equal-mass case, we review the nature of polaron-molecule transition that is driven by two-body correlations, and especially highlight the finite momentum character and huge degeneracy of molecule states. For the mass-imbalanced case, we focus on the smooth crossover between polaron and various dressed clusters that originate from high-order correlations. These competing few-body correlations reviewed in Fermi polarons suggest a variety of exotic new phases in the corresponding many-body system of Fermi-Fermi mixtures. [ABSTRACT FROM AUTHOR]

With the increasing requirements from toxic and hazardous gas detection technologies, WO 3 -based gas sensors have garnered tremendous interest on account of their low operating temperatures, good cycling stability, and short response/recovery time. So far, considerable progress has been made in the design and preparation of different architectures of WO 3. The sensing mechanism of WO 3 -based gas sensors is relatively complex. To further optimize the capabilities of WO 3 -based gas sensors, the influencing factors of the sensing mechanism need to be deeply understood to seek more effective enhanced strategies. This review probes the application of WO 3 -based sensors for various dangerous gases and contrastively analyses the sensing behavior of WO 3 in detail. In addition, we pay special attention to the interfacial interaction pathways between the sensing material and the target gas. Nowadays, more efforts are being made to strengthen the sensing properties of WO 3 -based materials so that they can be used in more smart demanding and complex environments. The authors focus on four approaches, namely, morphology control, hybridization, defect engineering, and photoactivation, for enhancing gas sensors and providing a comprehensive study of WO 3 for gas-sensing applications. Finally, we discuss the current problems and improvement methods and provide an outlook on the development trend of WO 3 -based gas sensors. The WO 3 -based gas sensitive materials are reviewed from adsorption, reactive and transducing interfacial issues, and their sensitivity and selectivity can be improved prominently by quaternary strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the feasibility of hydrophobizing pine wood veneers through gas grafting with palmitoyl chloride using a hot press was explored. To achieve this, the hydrophobization characteristics of wood veneer were analyzed under various conditions, including pressing temperature, time, and concentration of palmitoyl chloride. The results showed that the gas grafting treatment successfully hydrophobized the pine wood veneer, and that the pressing temperature and concentration of palmitoyl chloride were the main factors influencing the grafting. The hydrophobization efficiency increased with an increase in the pressing temperature and palmitoyl chloride concentration, whereas the pressing time had little effect. However, under conditions of excessively high palmitoyl chloride concentration, pressing temperature, and excessively long pressing time, relatively large color changes and a pH drop in the veneer were observed. Therefore, it was concluded that to treat pine wood veneer with a diluted solution of 0.5 % palmitoyl chloride at 180 °C for 6 s was appropriate. [ABSTRACT FROM AUTHOR]

Despite their use in ophthalmology for more than a century, there are no fundamental biophysical models that account for the dissolution rate of intra-ocular gas bubbles in vivo, as a function of their initial size and composition. Any physical model that reliably predicts the evolution of these bubbles would be extremely useful for planning treatment, by predicting their size over time, and their periods of clinical usefulness. A fundamental, computational, biophysical model is developed here with these purposes in mind. The model is fundamental in the sense that the underlying rate equations are derived using linear response theory, wherein the driving force is a solute chemical potential difference. It is computational because the rate equations for the bubble volume and composition are fully coupled and must be integrated numerically and simultaneously. It was rendered clinically relevant by fitting its two adjustable parameters (two rate constants) to recently acquired live human eye data on intra-ocular air bubble dissolution rates. The model consists of an explicitly four-component, dome-shaped gas bubble, comprised of N2, O2, H2O and CO2, which exchanges N2 and O2 with circulating venous blood in the capillaries of the eye. The calibrated model provided an excellent fit to the available data, and interpolated nicely through three points not used for the calibration. It was used to show that by selecting different N2/O2 ratios in the initially injected gas, one can generate intra-ocular gas bubbles with significantly different predicted periods of clinical usefulness. This potentially useful predictive capability does not exist in current clinical practice. [ABSTRACT FROM AUTHOR]

This paper presented a novel numerical method for estimating the gas diffusion coefficient based on the early-time pressure-decay data. Experimentally, "flooding–soaking" procedures were developed to perform the gas diffusion in an oil-saturated tight core under different gas phase volume conditions. After flooding, the capillary bundle model was used to calculate the oil–gas contact area. The early-time pressure-decay data of the gas phase were monitored and recorded during the soaking process. Theoretically, a non-equilibrium inner boundary condition coupled with the characteristics of experimental early-time pressure had been incorporated to develop a diffusion model for a gas/oil-saturated tight core system. Based on gas-phase mass balance equations and gas equation of state, the diffusion coefficients were optimized once the discrepancy between experimental data and numerical solutions was minimized. According to the estimated results in this study, the CH4 diffusion coefficients were 3.74 × 10−11 and 3.86 × 10−11 m2/s in tight core saturated with crude oil, respectively. Moreover, the oil–gas contact area significantly impacts the diffusion flux in oil-saturated porous media. Specifically, an additional 10% contact area results in a 75% increase in CH4 diffusion mass. In addition, with the application of our proposed model to CH4/bitumen and CO2/bitumen systems, the diffusion coefficients were in close agreement with the results reported in previous literature, indicating that the proposed model was applicable to both gas/liquid and gas/liquid-saturated porous media systems. [ABSTRACT FROM AUTHOR]

Data-driven methods are of great interest in studying the hydrodynamics of gas–solid flows. In this paper, we developed an optimized dynamic mode decomposition with control (DMDc) method for long-term and fast prediction of one physical field with the aid of another physical field. Using the computational fluid dynamics-discrete element method (CFD-DEM) simulation results as the benchmark, the prediction ability of the standard DMDc method and the optimized DMDc method is evaluated. It was shown that the optimized DMDc method is superior when the order of magnitude of the predicted data is much larger than that of the auxiliary data, which cannot be addressed by using scaled or dimensionless data, for instance, the prediction of gas pressure with the aid of solid volume fraction; on the other hand, both DMDc and optimized DMDc methods can reasonably predict the long-term behavior of gas–solid flows, when the magnitude of the elements of the predicted field is comparative to that of the auxiliary field. This study proposes a fast and relatively accurate method for predicting the hydrodynamics of gas–solid flows with the aid of a known field. [ABSTRACT FROM AUTHOR]

The trigger generator made with a spiral generator (SG) has the advantages of light weight, compact structure, and low cost and has promising applications in the pulsed power field. This paper introduces a compact solid-state high-voltage pulse trigger system based on an improved SG, which has improved repetition rate and lowered the demands for semiconductor switches' maximum current and current rise rate when compared with previous studies. The improvement is achieved by winding outward an additional layer of the passive layer and low-voltage metal strip, which realizes a significant reduction of the peak current and current rise rate of the discharge switch. The final dimension of the trigger is 25 × 10 × 10 cm3, excluding the power supply. An experiment carried out in single shot mode shows that the peak value of the output pulse can reach 50 kV with a leading edge of 57 ns. Repetitive experiments were carried out up to 1 kHz, with the peak voltage of the output pulse being 30.5 kV, the leading edge being 48 ns, and the jitter being 0.84 ns. Finally, the generator is used to trigger a gas switch, and it works stably and reliably. [ABSTRACT FROM AUTHOR]

The ongoing transition in the energy sector demands more efficient and reliable energy storage solutions. Our study addresses this need by optimizing the industrial process of liquefied natural gas (LNG) storage, focusing on enhancing thermal performance and energy efficiency. Leveraging a standard LNG storage design, we meticulously evaluated critical supporting variables, modeled key components, and conducted integrated cycle simulations. The primary goal was to minimize the volume of stored gas (achieving a reduction to approximately 1/600th of its gaseous state) while maintaining optimal storage conditions. Our methodology prioritizes insulation over pressure‐bearing factors in large‐scale tanks, aligning with the unique thermal challenges of LNG storage. Simulations were based on methane, which constitutes over 86% of the natural gas in the Middle East, ensuring relevance to the region's resources. The results are promising, with a compression stage reaching a maximum pressure of 2.377, an energy efficiency ratio of 60.71%, and a performance coefficient of 3.188. These findings offer a significant step forward in developing more effective and efficient LNG storage systems, contributing to the broader goal of sustainable energy management. [ABSTRACT FROM AUTHOR]

Density–density correlation analysis is a convenient diagnostic tool to reveal the hidden order in the strongly correlated phases of ultracold atoms. We report on a study of the density–density correlations of ultracold bosonic atoms which were initially prepared in a Mott insulator (MI) state in one-dimensional optical lattices. For the atomic gases released from the deep optical lattice, we extracted the normalized density–density correlation function from the atomic density distributions of freely expanded atomic clouds. Periodic bunching peaks were observed in the density–density correlation spectra, as in the case of higher-dimensional lattices. Treating the bosonic gas within each lattice well as a subcondensate without quantum tunneling, we simulated the post-expansion density distribution along the direction of the 1D lattice, and the calculated density–density correlation spectra agreed with our experimental observations. [ABSTRACT FROM AUTHOR]

A gas analyzer has been developed using cavity ring‐down spectroscopy (CRDS) technology, designed to simultaneously measure the concentrations of CO2 and CO. These gases are critical indicators of transformer insulation degradation. The analyzer covers a CO2 concentration range from a few ppm to several thousand ppm and can measure CO/CO2 concentration ratios from 0.076 to 0.8. The selected absorption lines for CO and CO2 are centered at 6337.99 and 6338.59 cm−1, respectively. The two candidate lines are proximate to each other and nonoverlapping. The experimental results indicate that the system accurately fits the measured and calculated signals, enabling concentration measurements at the ppm level. This confirms its ability to measure the gas concentrations and ratios critical for assessing the condition of transformer insulation. This CRDS‐based system offers a reliable and sensitive method for early detection of potential transformer faults. [ABSTRACT FROM AUTHOR]

In the present paper, we studied the microstructural and sensing behaviors of undoped SnO2 and PbO-doped SnO2 thick film. Three samples have been fabricated using the screen-printing technique on an aluminum substrate and these are S1 (undoped SnO2) S2 (1wt% PbO doped SnO2 firing at 800 oC), and S3 (1 wt% PbO doped SnO2 firing at 900 oC). XRD and AFM techniques are used to observe the microstructural behaviors and it is found that the crystallite size decreases with PbO doping. The reduction in crystallinity is to improve the sensing application. The sensing properties such as sensing response, selectivity, and transient time of the deposited thick films were studied at an operating temperature of 200 oC for various test gases such as ethanol, LPG, and acetone concentrations (0–5000 ppm level). Also, we found that the response of sensor S3 to the ethanol gas is ~ 3.38 times of LPG and ~ 1.95 times that of acetone gas. The response and recovery times of the ethanol gas for the S3 sensor are 41s and 125s, respectively. Therefore, the PbO doping improves the response and recovery time for ethanol gas (5000 ppm) over LPG and acetone. [ABSTRACT FROM AUTHOR]

In Europe, respiratory protective devices must be certified before they can be marketed. Among the parameters of interest, inward leakage (IL) characterizes the tightness between the face seal and the face, to verify that the device is well-designed. European standard EN 13274-1 (2001) and International Organization for Standardization (ISO) standard ISO 16900-1 (2019) specify that IL should be measured using sodium chloride (NaCl) aerosol or sulfur hexafluoride (SF6) gas. For reusable masks made of nonporous materials, both test agents are considered equally acceptable. However, the few studies that have compared IL values measured with various aerosols and gases have come to divergent conclusions. This work then aimed to measure IL with the test agents recommended by the standards to determine whether they are really equivalent. Since krypton (Kr) is an interesting candidate for replacing SF6 in standard tests, IL was assessed with SF6 and Kr simultaneously, and with NaCl aerosol using various calculation methods. Tests were carried out on 5 models of full-face masks donned on a headform connected to a breathing machine simulating 3 sinusoidal breathing rates of various intensities. The respirator fit on the headform was evaluated using a controlled negative pressure method to determine a manikin fit factor. Four scenarios were then tested to represent very poor, bad, good, and excellent fit. Gas concentration was measured using a mass spectrometer, and IL was calculated for SF6 and Kr. A combination of 3 devices allowed the determination of the number-based concentration of particles with diameters between 20 nm and 2 µm, and IL was calculated for each of the 33 channels, as well as using a cumulative number concentration. In addition, to comply with standards, a conversion was carried out to calculate IL using a cumulative mass concentration. The results of this work evidenced that the IL values measured with NaCl were systematically lower than those determined with gases. IL was also shown to vary with particle size, with a maximum value exceeding that calculated with cumulative concentrations (in number or mass). As part of the revision of the standards, protocols for measuring inward leakage should be redefined. On the one hand, acceptability thresholds should be re-evaluated according to the nature of the test agent (gas or aerosol), as it is clear that the 2 options do not give the same results for a given configuration. On the other hand, the aerosol leakage measurement protocol needs to be reworked to enable the measurement of a well-defined, robust, and reproducible inward leakage value. [ABSTRACT FROM AUTHOR]

Thiophosgene is one of the principal C=S building blocks in synthetic chemistry. At room temperature, thiophosgene is a red liquid. While its properties in the liquid and gaseous states are well known, a comprehensive characterization of thiophosgene in its solid state is presented here. Differential scanning calorimetry shows that thiophosgene forms a supercooled melt before rapidly crystallizing. Its melting point is 231.85 K (−41.3 °C). At 80 K, thiophosgene crystallizes in space group P63/m [No. 174, a = b = 5.9645 (2), c = 6.2835 (3) Å, V = 193.59 (2) Å3]. The molecule shows a distinct rotational disorder: all S and Cl positions are of mixed occupancy and the disorder does not resolve at temperatures as low as 10 K, as was shown by neutron powder diffraction. Infrared, Raman and inelastic neutron scattering spectra were collected and assigned with the aid of quantum chemical calculations. A larger ordered structural model allowed for better agreement between the measured and calculated spectra, further indicating that disorder is an inherent feature of solid‐state thiophosgene. [ABSTRACT FROM AUTHOR]

Summary: The integration of multi‐energy within distribution networks has escalated the need for efficient operation and control of integrated energy systems (IES). Addressing the complexities of real‐time scheduling and low‐carbon optimization, we propose a novel artificial intelligence driven multi‐agent system (MAS) approach for modeling the interactions and operations within the multi‐agent integrated energy systems (MA‐IES) framework. In this framework, distinct components such as electric, gas, and heat networks are conceptualized as autonomous agents, each responsible for managing its domain while interacting with other agents to achieve system‐wide efficiency and economical goals. The agents communicate and coordinate through a distributed online optimization framework, utilizing the alternating direction multiplier method (ADMM) to ensure effective consensus despite the inherent nontransparency of information exchange. This MAS based approach allows for dynamic adaptation of strategies based on local data and global objectives, significantly enhancing the responsiveness and adaptability of MA‐IES. We further integrate an objective function reliant on a tiered carbon pricing mechanism to assess and minimize the environmental impact of operations. Enhanced by adaptive penalty coefficients within the ADMM, our MA‐IES framework demonstrates improved convergence rates and robustness in operational scenarios. Empirical validation through detailed case studies confirms the superior performance of our MAS‐based model, demonstrating its potential to realize an efficient and economical low‐carbon operation of MA‐IES. [ABSTRACT FROM AUTHOR]

BACKGROUND: During invasive mechanical ventilation, where medical gases are very dry and the upper airway is bypassed, appropriate gas conditioning and humidification are mandatory at all times. Results of in vitro studies suggest that dry gases may improve lung deposition during nebulization, but this has not been confirmed through in vivo studies. The objective of this study was to measure gas humidity under multiple conditions to better describe gas hygrometry when heated humidifiers are turned off. METHODS: We measured, on a bench, the hygrometry of different gases at steady state: medical gases, at the Y-piece without humidifier, with the humidifier switched off, and with humidifier switched on. We measured gas humidity every 10-60 s during dynamic conditions after switching off the heated humidifier and after switching on the heated humidifier. Hygrometry was measured by using the psychrometric method with at least 3 measurements for each tested condition. RESULTS: We performed 287 psychrometric measurements in different situations. The mean ± SD gas absolute humidity at steady state during different conditions were the following: 1.6 ± 0.2 mg H2O/L for the medical gases, 4.5 ± 0.9 mg H2O/L at the Y-piece without humidifier, 9.1 ± 0.3 mg H2O/L at the Y-piece with heated humidifier turned off, and 34.2 ± 2.2 mg H2O/L at the Y-piece with the heated humidifier turned on. During the dynamic evaluation, after turning off the humidifier, humidity was < 30 mg H2O/L after a few minutes, attained 15 mg H2O/L after 15 min, and was below 10 mg H2O/L after 1 h but never reached the level of dry medical gases. After turning on the heated humidifier, the gas hygrometry reached 30 mg H2O/L after 5 min. CONCLUSIONS: When heated humidifiers are turned off, gas humidity levels are very low but not as low as medical gases. The clinical impact of repeated shutdowns is unknown. As recommended, heated humidifiers should never be turned off during nebulization. [ABSTRACT FROM AUTHOR]

Accurately predicting the performance of gas foil bearings (GFBs) is important. This paper presents a new fully coupled elastic–aerodynamic model for analyzing the static performance of gas foil journal bearings (GFJBs). The gas compressible lubrication model was solved in MATLAB to obtain the gas pressure. The foil structure deformation was solved in COMSOL by considering the Coulomb friction and allowing the contact surfaces to be separated from each other. Under given load and rotational speed conditions, the calculated minimum gas film thickness and attitude angle match well with the literature data, validating the accuracy of the developed model. Based on the model developed, a comprehensive and systematic analysis of the effects of the structural parameters on the static performance was performed. The results showed that as the bump height, top foil thickness, and bump foil thickness increased, the load capacity could be improved to different degrees. The bump foil thickness had the greatest effect on the load capacity. These results provide theoretical guidance for the structural design and practical applications of GFJBs. [ABSTRACT FROM AUTHOR]

Problem: Predicting dependency relationships in nonequilibrium systems is a critical challenge in complex systems research. Solution proposed: In this paper, we propose a novel method for predicting dependent edges in network models of nonequilibrium complex systems, based on overlapping module features. This approach addresses the many-to-many dependency prediction problem between nonequilibrium complex networks. By transforming node-based network models into edge-based models, we identify overlapping modular structures, enabling the prediction of many-to-many dependent edges. Experimental evaluation: This method is applied to dependency edge prediction in power and gas networks, curriculum and competency networks, and text and question networks. Results: The results indicate that the proposed dependency edge prediction method enhances the robustness of the network in power–gas networks, accurately identifies supporting relationships in curriculum–competency networks, and achieves better information gain in text–question networks. Conclusion: These findings confirm that the overlapping module-based approach effectively predicts dependencies across various nonequilibrium complex systems in diverse fields. [ABSTRACT FROM AUTHOR]

To improve the performance of genetic algorithms (GAs) in complex optimization settings, this work offered two novel real-coded crossover operators: one based on the Gumbel distribution (GX) and the other on the Rayleigh distribution (RX). These innovative operators, when combined with three different mutation techniques, created a significant improvement in GA methodology. Our meticulous simulations showed that the GX operator significantly outperformed RX and other traditional operators, demonstrating its superior capacity to address complex optimization problems. The GX operator's unusual robustness was further validated through detailed performance analysis utilizing the VlseKriterijuska Optimizacija I Komoromisno Resenje (VIKOR) multi-criteria decision-making technique, setting a new standard in crossover operator design and significantly improving the state of the art in GAs. [ABSTRACT FROM AUTHOR]

In this paper, a gas microbody is proposed to address the issues related to the limited load‐carrying capacity of squeezed film gas bearings, complex mechanical structures, large overall dimensions, high manufacturing costs, and complicated installation. Initially, the gas continuity equation of squeezed film was established for modal analysis, without regard to the gas inertial force and the gas volume force which are all far less than the gas viscous force. Then the load‐carrying characteristics of squeezed film gas bearing were studied and analyzed with the fluid‐structure coupling method. The load‐carrying capacity of the squeezed film gas bearing is determined by factors such as bearing amplitude, rotor‐axial clearance, and rotor‐axial tile contact area. In conclusion, the load‐carrying capacity can be enhanced by increasing the amplitude value, reducing the clearance, and increasing the contact area. Among them, when adjusting the amplitude and clearance to improve the bearing's load‐carrying capacity, the stability of bearing operation should be considered. When the clearance is too small, the pressure distribution of the air film will be uneven, and when the contact area is too large, the development of the air film in all directions will be asymmetrical. [ABSTRACT FROM AUTHOR]

This paper presents an analytical investigation into the propagation of a normal shock wave in Van der Waals gas flow, employing the Buongiorno model. It explores the dynamics of this flow type under a shock wave, considering modified Rankine–Hugoniot (RH) jump conditions within the Buongiorno model framework. By solving the RH conditions, this study provides a solution for gas flows with varying nanoparticle concentrations, facilitating an examination of parameter variations under discontinuity. The abstract further emphasizes the graphical representation of velocity coefficient and pressure in adiabatic gas flow during a shock wave, considering compressive and exponential waves. The analysis accounts for nanoparticle concentration and non-ideal parameters. [ABSTRACT FROM AUTHOR]

The stability of the plugging zone has a great impact on lost circulation control and gas invasion prevention in fractured reservoirs. In this work, the concept of "cavitation‐induced shear failure" is put forward based on the analysis of the flow field characteristics, and the failure mechanism is discussed. The strength physical model of a fractured plugging zone is formed based on the analysis of the characteristic parameters of LCMs and the failure mechanism. And then the simulation experiments of cavitation‐induced shear failure, gas invasion prevention, pressure bearing, and tight plugging are carried out. The research shows that (1) the fractured plugging zone is a dense granular matter system, and the contact forces and quid bridge force are dominant in its internal; (2) the cavitation‐induced shear failure is one of the main failure modes of the plugging zone in a fractured gas reservoir, and the failure process includes three steps: gas diffusion‐dilution damage, confluence and carry damage, and displacement dislocation shear failure; (3) the strengthening model of the plugging zone, "rigid bridging+elastoplastic filling+lacing wire of fiber+film‐forming seal," is a better model, and experiments prove that it can form a tight pressure‐bearing plugging zone, preventing drill‐in fluid loss. The research results provide a theoretical and technical basis for the lost circulation control of fractured gas formations. [ABSTRACT FROM AUTHOR]

The high specific surface area of graphene is an important factor to enable a large molecular adsorption on the surface, thus enabling direct sensing on a versatile surface. A large area graphene sensor (1 cm2) is fabricated using a transfer method for the detection of ammonia (NH3) gas under ambient conditions. The ambient atmosphere contains 21% oxygen (O2), and thus it is crucial to understand its impact on the sensing of ammonia gas. The sensing response is analyzed under both the inert nitrogen (N2) gas and condensed dry air (CDA) containing 78.08% N2, 20.95% of O2, and 0.93% of argon gas. Upon interaction with the graphene, both NH3 and O2 resulted in opposite electrical responses. Thus, this finding reveals a polarity dependent interaction of gases with the graphene. [ABSTRACT FROM AUTHOR]

Plasma-activated water can efficiently inactivate pathogenic microorganisms and is considered to be a potent disinfectant in the medical, food, and agricultural industries. In this study, the air discharged by the gliding arc was mixed with different gases including O2, ambient air, synthetic air, and N2 at different flow rates to produce the activated gases, which were then activated gases were inducted into saline to prepare plasma-activated saline (PAS). The gaseous reactive species in the activated gases were composed of NO, NO2, and N2O5 and the aqueous reactive species in the PAS included H2O2, NO2−, NO3–, ⋅ OH , and 1O2 with different intensities, while the inactivation effects of the PAS also varied with the type and the flow rates of the mixed gases in the activated gases. The inactivation effects of the PAS treated by the discharged air mixed with O2, ambient air, and synthetic air started to become weak after 3 h placement. Scavenger analysis demonstrated that the 1O2 played a critical role in the inactivation process. This study indicated that air discharged by the gliding arc mixed with different gases could regulate the reactive species and the biological effects of PAS, providing insight into the preparation of PAS applied for disinfection. [ABSTRACT FROM AUTHOR]

Hydrological changes in groundwater coupled with earthquakes had been documented in previous studies by global researchers. Although few reports investigate multiple geochemical parameters that respond to earthquakes, trace elements received less attention, whereas they were suggested to be more sensitive to small earthquakes than the commonly used geochemical parameters. Beijing is located in the Zhangjiakou-Bohai(Zhang-Bo) seismic belt of North China, and although the occurrence of small earthquakes is frequent, the great historic earthquake in the Sanhe-Pinggu area M8 in 1679 in the adjoining southeast of Beijing gained widespread public attention. To find effective precursors that are significant for operational earthquake forecasting of the Beijing area, we carried out a one year test research project through weekly collection of groundwater samples during June 2021 to June 2022 from the seismic monitoring well of Wuliying in northwest Beijing. The 41 trace elements chemical compositions were analyzed for each sample. During the project ongoing period, the biggest earthquake with a magnitude of ML3.3 occurred in the Chaoyang District of Beijing on 3 February 2022. The content changes in these trace elements were systematically monitored before and after the earthquake. Through retrospective research, it was found that a few sensitive trace elements were anomalous to be coupled to the earthquake, including Li,Sc, Rb, Mo, Cs, Ba, W, U, Sr, Mn, Ni,andZn. In addition to trace elements, we examined stable isotopes of hydrogen and oxygen and the existing hydrological data on groundwater level, temperature, major ions, and gases to assess the validity of geochemistry as a monitoring and predictive tool. We only found that F(fluorine) ions and He (helium) gas had apparent shifts related to the earthquakes, while no shifts in the groundwater level were observed. Such characteristics of multiple geochemical parameters indicate that trace elements are likely to be more sensitive to crustalstrain than the groundwater level and major ions. We assumed a most likely mechanism of the combination of mixing and water-rock interactions to explain the phenomenon. The probable scenario was that minor stresses caused by the earthquakes might create microcracks in bedrocks, thereby leading to a small volume of chemically distinct water mixing with the original water of the aquifer, and finally, the earthquakeinduced rock fractures enhance the water-rock interactions, resulting in the post-seismic recovery of trace elements and δ180 value migration to the GWML. More testing works to find other sensitive sites to investigate multiple geochemical characteristics aiming at long-term to short-term earthquake prediction in the Beijing area and Zhang-Bo seismic belt are in progress. [ABSTRACT FROM AUTHOR]

To address the challenges of high experimental costs, complexity, and time consumption associated with pre-mixed combustible gas deflagration experiments under semi-open space obstacle conditions, a rapid temporal prediction method for flame propagation velocity based on Ranger-GRU neural networks is proposed. The deflagration experiment data are employed as the training dataset for the neural network, with the coefficient of determination (R2) and mean squared error (MSE) used as evaluation metrics to assess the predictive performance of the network. First, 108 sets of pre-mixed methane gas deflagration experiments were conducted, varying obstacle parameters to investigate methane deflagration mechanisms under different conditions. The experimental results demonstrate that obstacle-to-ignition source distance, obstacle shape, obstacle length, obstacle quantity, and thick and fine wire mesh obstacles all significantly influence flame propagation velocity. Subsequently, the GRU neural network was trained, and different activation functions (Sigmoid, Relu, PReLU) and optimizers (Lookahead, RAdam, Adam, Ranger) were incorporated into the backpropagation updating process of the network. The training results show that the Ranger-GRU neural network based on the PReLU activation function achieves the highest mean R2 value of 0.96 and the lowest mean MSE value of 7.16759. Therefore, the Ranger-GRU neural network with PReLU activation function can be a viable rapid prediction method for flame propagation velocity in pre-mixed methane gas deflagration experiments under semi-open space obstacle conditions. [ABSTRACT FROM AUTHOR]

In-depth understanding of the gas–water seepage law caused by different degrees of gas layer perforation and varying gas production rates is key to determining a reasonable development technology policy for vertical heterogeneous edge-water gas reservoirs. Based on core physical data from the entire section of the X2 well, a large-scale high-pressure positive-rhythm profile model that takes into account the influence of "discontinuous interlayer" was innovatively established. The water intrusion process of the gas layer profile under different gas production rates and degrees of gas layer perforation was simulated using an electrical resistivity scanning device. The experimental model has an area of 3000 cm2, with a maximum pressure of 70 MPa and a maximum temperature resistance of 150 °C. It includes 456 evenly distributed fluid saturation test points to accurately monitor the gas–water distribution, addressing the issues of small bearing pressure and insufficient saturation monitoring points found in other large-scale models. The experimental results show that, in heterogeneous reservoirs, the high-permeability zone controls the invasion path of edge water, which is the main reason for the uneven invasion of edge water. For the positive-rhythm profile of the F layer, a higher gas production rate (1000 mL/min) shortens the water-free gas recovery period of the gas well and reduces the recovery rate. Perforating the upper two-thirds of the layer can inhibit edge-water breakthrough, prolong the water-free gas recovery period of the gas well, enable the gas–water interface to advance more uniformly, and enhance the recovery degree. The results of this study greatly enhance our understanding of the water invasion characteristics of positive-rhythm reservoirs under the influence of different gas production rates and varying degrees of gas layer perforation. [ABSTRACT FROM AUTHOR]