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This study reports light narrowing in paraffin-coated vapor cells from room temperature 27 to 59 °C, where spin-exchange relaxation is suppressed. By means of a coating lock and eliminating the reservoir effect, an ultra-narrow magnetic resonance linewidth of 0.36 Hz and an atomic coherence lifetime of T 2 = 0.9 s are achieved. In cells free of buffer gas, the narrow linewidth over this broad temperature range is a result of enhanced spin polarization, which is facilitated by the effective suppression of radiation trapping benefiting from the stability of the vapor density. Using such cells in atomic magnetometers, the photon shot noise limit is estimated as 0.2 fT / Hz 1 / 2 and the spin-projection noise limit is estimated as 1.1 fT / Hz 1 / 2 . Also, a magnetometer system with the stable coated cell is identified, which demonstrates the potential for achieving relatively stable magnetometer sensitivity without precisely controlling the cell temperature. The long coherence lifetime and the broad operating temperature range expand the potential applications of quantum memory and other quantum sensors such as atomic clocks. [ABSTRACT FROM AUTHOR]

This article presents methodological advances in the state-of-the-art for making time-dependent, thermochemical measurements within kilogram-scale explosive post-detonation fireballs utilizing tunable laser absorption spectroscopy. This measurement capability is critical for validating multi-scale, multi-physics models of post-detonation dynamics. The technique is based on hardened gauges built around rapidly-tunable lasers and custom post-processing algorithms that provide quantitative thermochemical data interior to large and opaque explosive fireballs. The authors present a holistic overview of the technique including gauge design, the laser absorption diagnostic, and the custom data processing algorithms. Additionally, fielding high-bandwidth laser absorption probes at stand-off ranges presents new challenges in data processing that must compensate for long distance signal transmission effects. We highlight representative data from a hardened gauge measurement at 0.81 m stand-off from a 2.78 kg LX-14 explosive charge detonated in an outdoor test arena. We discuss progress in all-optical measurement of temperature, pressure, and water vapor number density at a 100 kHz repetition rate during the first 10 ms of the fireball evolution. We conclude the article with a brief discussion on our current approach for comparing hardened gauge measurements with computational fluid dynamic simulations. [ABSTRACT FROM AUTHOR]

Transition metal catalyzed chemical vapor deposition (CVD) is considered as the most promising approach to synthesize highquality graphene films, and low-temperature growth of defect-free graphene films is long-term challenged because of the high energy barrier for precursor dissociation and graphitization. Reducing the growth temperature can also bring advantages on wrinkle-free graphene films owing to the minimized thermal expansion coefficient mismatch. This work focuses on density functional theory (DFT) calculations of the carbon source precursor with hydroxyl group, especially CH3OH, on low-temperature CVD growth of graphene on Cu and CuNi substrate. We calculated all the possible cleavage paths for CH3OH on transition metal substrates. The results show that, firstly, the cleavage barriers of CH3OH on transition metal substrates are slightly lower than those of CH4, and once CO appears, it is difficult to break the C-O bond. Secondly, the CO promotes a better formation and retention of perfect rings in the early stage of graphene nucleation and reduces the edge growth barriers. Thirdly, these deoxidation barriers of CO are reduced after CO participates in graphene edge growth. This paper provides a strategy for the lowtemperature growth of wrinkles-free graphene on transition metal substrates using CH3OH. [ABSTRACT FROM AUTHOR]

Ice formation mechanisms in generating cells near stratiform cloud tops, where mixing and entrainment occurs in the presence of supercooled water droplets, remain poorly understood. Supercooled cloud droplet temperature and lifetime may impact heterogeneous ice nucleation through contact and immersion freezing; however, modeling studies normally assume the droplet temperature to be spatially uniform and equal to the ambient temperature. Here, we present a first-of-its-kind quantitative investigation of the temperature and lifetime of evaporating droplets, considering internal thermal gradients within the droplet, as well as thermal and vapor density gradients in the surrounding air. Our approach employs solving Navier–Stokes and continuity equations, coupled with heat and vapor transport, using an advanced numerical model. For typical ranges of cloud droplet sizes and environmental conditions, the droplet internal thermal gradients dissipate quickly (≤ 0.3 s) when droplets are introduced to new subsaturated environments. However, the magnitude of droplet cooling is much greater than estimated from past studies of droplet evaporation, especially for drier environments. For example, for an environment with 500 hPa pressure, and ambient temperature far from the droplet of - 5 °C , the droplet temperature reduction can be as high as 24, 11, and 5 °C for initial ambient relative humidities of 10 %, 40 %, and 70 %, respectively. Droplet lifetimes are found to be tens of seconds longer compared to previous estimates, due to weaker evaporation rates because of lower droplet surface temperatures. Using these new end-of-lifetime droplet temperatures, the enhancement in the activation of ice-nucleating particles predicted by current ice nucleation parameterization schemes is discussed. [ABSTRACT FROM AUTHOR]

This study evaluates the capability of an unconstrained tomographic algorithm to capture 3D water vapor density variability throughout 2017 in Houston, U.S. The algorithm relies solely on Global Navigation Satellite System (GNSS) observations and does not require an initial guess or other specific constraints regarding water vapor density variability within the tomographic domain. The test domain, featuring 9 km horizontal, 500 m vertical, and 30 min temporal resolutions, yielded remarkable results when compared to data retrieved from the ECMWF Reanalysis v5 (ERA5), regional Weather Research and Forecasting Model (WRF) data, and GNSS-Radio Occultation (RO). For the first time, a time series of Precipitable Water Vapor maps derived from the Interferometric Synthetic Aperture Radar (InSAR) technique was used to validate the spatially integrated water vapor computed by GNSS tomography. Tomographic results clearly indicate the passage of Hurricane Harvey, with integrated water vapor peaking at 60 kg/m2 and increased humidity at altitudes up to 7.5 km. Our findings suggest that GNSS tomography holds promise as a reliable source of atmospheric water vapor data for various applications. Future enhancements may arise from denser and multi-constellation networks. [ABSTRACT FROM AUTHOR]

Using a simple and cost-effective water jet process, silicon etch depth limitations are overcome to realize a 6 mm deep atomic vapor cell. While the minimum silicon feature size was limited to a 1.5 mm width in these first generation vapor cells, we successfully demonstrate a two-chamber geometry by including a ∼ 25 mm meandering channel between the alkali pill chamber and the main interrogation chamber. We evaluate the impact of the channel conductance on the introduction of the alkali vapor density during the pill activation process and mitigate glass damage and pill contamination near the main chamber. Finally, we highlight the improved signal achievable in the 6 mm silicon cell compared to standard 2 mm path length silicon vapor cells. [ABSTRACT FROM AUTHOR]

An efficient method is proposed for quantifying rubidium vapor density by analyzing the spin‐exchange rate between alkali metals. This method effectively addresses two primary challenges in measuring alkali vapor density. First, it overcomes the limitation of absorption spectroscopy to measure vapor density under optically thick conditions, typically restricted to temperature higher than 420K, equivalent to alkali vapor density exceeding 1014${10^{14}}$cm−3${{\rm {cm}}^{-3}}$. Second, it mitigates the risk of disrupting shielding functionality due to the application of a strong magnetic field, often in the range of several tens of Gauss or higher, when employing the Faraday rotation for vapor‐density measurement. The spin‐exchange rate between 87Rb${}^{87}{\rm {Rb}}$ atoms, inherently related to the vapor density, is evident in the electron‐paramagnetic‐resonance spectrum of spin‐polarized 87Rb${}^{87}{\rm {Rb}}$, thereby providing a possibility for measuring alkali vapor density. To eliminate overlap between two Lorentzian curves resulting from two decomposed components of an oscillating field, a small rotating magnetic field with identical amplitude and frequency but a 90‐degree phase shift along both the x and y axes is applied. This method is successfully employed to measure 87Rb${}^{87}{\rm {Rb}}$ vapor density in the temperature range of 373–433 K, with the measured outcomes closely matching the saturation vapor curve. [ABSTRACT FROM AUTHOR]

Stationary or mobile microwave radiometers (MRs) can measure atmospheric temperature, relative humidity, and water vapor density profiles with high spatio-temporal resolution, but cannot obtain the vertical variations of wind field. Based on a dataset of brightness temperatures (TBs) measured with a mobile MR over the Three-River-Source Region of the Tibetan Plateau from 18 to 30 July 2021, we develop a direct retrieval method for the wind profile (WP) based on the Long Short-Term Memory (LSTM) network technique, and obtain the reliable dynamic variation characteristics of the WP in the region. Furthermore, the ground-based radiative transfer model for TOVS (RTTOV-gb) was employed to validate the reliability of the TB observation, and we analyzed the impact of weather conditions, altitude, observational mode, and TB diurnal variation on the accuracy of the TB measurement and the retrieval of the WP. Results show that the TB from the mobile observation (MOTB) on clear and cloudy days are close to those of the simulated TB with the RTTOV-gb model, while TB measurements on rainy days are far larger than the modeled TBs. When compared with radiosonde observations, the WPs retrieved with the LSTM algorithm are better than the ERA5 reanalysis data, especially below 350 hPa, where the root mean square errors for both wind speed and wind direction are smaller than those of ERA5. The major factors influencing WP retrieval include the weather conditions, altitude, observational mode, and TB diurnal variation. Under clear-sky and cloudy conditions, the LSTM retrieval method can reproduce the spatio-temporal evolution of wind field and vertical wind shear characteristics. The findings of this study help to improve our understanding of meso-scale atmospheric dynamic structures, characteristics of vertical wind shear, atmospheric boundary layer turbulence, and enhance the assessment and forecasting accuracy of wind energy resources. [ABSTRACT FROM AUTHOR]

To better understand processes involved in the evaporative drying of the soil, simulations on the dynamics of the evaporation zone, condensation zone, and dry surface layer (DSL) were conducted during a 10-day drying event under diurnal atmospheric conditions. Simulated water contents and soil temperatures matched well with the measured data in the lysimeter. Surface evaporation predominantly occurred during the early period each day, while subsurface evaporation dominated during the remaining part of the day. The evaporation zone presented a distinctly diurnal pattern, moving toward the deeper soil layer during the daytime and back toward the soil surface during the nighttime. The DSL and condensation zone, located immediately above and below the evaporation zone, respectively, also presented diurnal patterns following those of the evaporation zone. As soil drying progressed, both the position of the evaporation zone within the profile and the DSL width exhibited an overall increasing trend, reaching about 4.9 mm by the end of the study period. The occurrence of condensation zones was limited to the daytime when there was a downward surface temperature gradient present. Diurnal patterns observed in both evaporation zones and DSL could potentially be determined by quantifying changes in the near-surface profile's soil water content, relative humidity, pressure head, and vapor density. [ABSTRACT FROM AUTHOR]

To predict the size (m, σ) and energy (ε) parameters of the perturbed‐chain statistical associating fluid theory (PC‐SAFT) based on the conductor‐like screening model for realistic solvents (COSMO‐RS), in this work, the PC‐SAFT model parameters of 304 substances were reviewed and summarized, their COSMO‐RS results linked to the size and energy were predicted, and the relationships between the PC‐SAFT parameters and COSMO‐RS results were obtained in 3 cases (Case 1: relationships based on n‐alkanes, Case 2: category‐specific relationships, Case 3: generic relationships for 138 substances). Case 2 (including Case 1) shows the lowest average absolute relative deviations (AARDs) of 7.63% (m), 3.05% (σ), and 9.05% (ε), while Case 3 provides the prediction capacity with AARDs of 10.00% (m), 4.05% (σ), and 13.21% (ε), which is better than those developed by others. Finally, the new PC‐SAFT parameters were used to predict the densities and vapor pressures of 8 representative substances and compared with the results using the original PC‐SAFT parameters, showing that the parameters in Case 3 can be used to reproduce densities and the parameters in Case 2 (including Case 1) can be used to reproduce both densities and vapor pressures. [ABSTRACT FROM AUTHOR]

Observations and measurements show that crystals remain relatively compact at low ice supersaturations, but become increasingly hollowed and complex as the ice supersaturation rises. Prior measurements at temperatures >−25°C indicate that the transition from compact, solid ice to morphologically complex crystals occurs when the excess vapor density exceeds a threshold value of about 0.05 g m−3. A comparable threshold is not available at low temperatures. A temperature-dependent criterion for the excess vapor density threshold (Δρthr) that defines morphological transformations to complex ice is derived from laboratory measurements of vapor grown ice at temperatures below −40°C. This criterion depends on the difference between the equilibrium vapor density of liquid ( ρ e l ) and ice (ρei) multiplied by a measurement-determined constant, Δ ρ thr ≃ 0.27 (ρ e l − ρ e i ) . The new criterion is consistent with prior laboratory measurements, theoretical estimates, and it reproduces the classical result of about 0.05 g m−3 above −25°C. Since Δρthr defines the excess vapor density above which crystals transition to a morphologically complex (lower density) growth mode, we can estimate the critical supersaturation (scrit) for step nucleation during vapor growth. The derived values of scrit are consistent with previous measurements at temperatures above −20°C. No direct measurements of scrit are available for temperatures below −40°C; however, our derived values suggest some measurement-based estimates may be too high while estimates from molecular dynamics simulations may be too low. [ABSTRACT FROM AUTHOR]

Evaporating a liquid sessile drop deposited on a horizontal surface is an important object of applications (printing technologies, electronics, sensorics, medical diagnostics, hydrophobic coatings, etc.) and theoretical investigations (microfluidics, self-assembly of nanoparticles, crystallization of solutes, etc.). The arsenal of formulas for calculating the slow evaporation of an axisymmetric drop of capillary dimensions deposited on a flat solid surface is reviewed. Characteristics such as vapor density, evaporation flux density, and total evaporation rate are considered. Exact solutions obtained in the framework of the Maxwellian model, in which the evaporation process of the drop is limited by vapor diffusion from the drop surface to the surrounding air, are presented. The summary covers both well-known results obtained during the last decades and new results published by us in the last few years, but practically unknown to the wider scientific community. The newest formulas, not yet published in refereed publications, concerning exact solutions for a number of specific contact angles are also presented. In addition, new approximate solutions are presented (total evaporation rate and mass loss per unit surface area per unit time in the whole range of contact angles θ ∈ [ 0 ,   π) , drop lifetime in constant contact radius evaporation regime and constant contact angle mode), which can be used in modeling without requiring significant computational resources. [ABSTRACT FROM AUTHOR]

In response to stringent rules inhibiting the implementation of refrigerants with high global warming impact, alternative candidates should undergo assessments to prove their viability. The mixtures R450A and R454B, being the center of the current focus, underwent experimentation for flow condensation inside a mini-scale micro-finned tube of 5 mm outer diameter. The operating conditions were set to be in the range of 0.1 to 0.95 for vapor quality, 75 to 400 kg m−2 s−1 for mass flux, and recorded at saturation temperatures of 30 and 40 °C. Having concluded the evaluations of thermal and hydraulic properties of heat transfer coefficient (HTC) and frictional pressure drop (FPD), a comparison was drawn between the two candidates, where R450A possessed superior HTC and higher FPD per unit length at higher vapor qualities due to lower vapor density. Ultimately, empirical models pertinent to flow condensation were compared with the acquired experimental results. [ABSTRACT FROM AUTHOR]

low frequency noise and electrical characteristics of the p-InAsSbP/n-InAs single photodiode heterostructures grown onto n+-InAs substrates have been measured in the presence of atmosphere containing ethanol vapor. Correlation between ethanol vapor density and electrical noise spectral density, as well as the heterostructure resistance, has been estimated, and possible reasons for such correlation have been discussed. [ABSTRACT FROM AUTHOR]

R-1243zf is a new refrigerant that could replace R-134a. Its thermodynamic properties represented in the equation of state (EOS) play an essential role in analyzing and designing thermal systems. The EOS exists without including caloric property data due to unavailable data during the development time. New EOS was developed explicitly in Helmholtz free energy and optimized to represent the experimental data accurately and maintain thermodynamic consistency. The optimization process undergoes using a genetic algorithm and weighted-least squares regression. The experimental data used in the optimization have a range of 233-430 K and 0.106-34.6 MPa and were validated from the extrapolation and consistency to confirm the reliability. The average absolute deviation from the data is 0.48% for the ideal gas isobaric specific heat, 1.7% for the isochoric specific heat, 0.33% for the speed of sound, 0.22% for the liquid density in single-phase, 0.49% for the vapor density in single-phase, 0.96% for the vapor pressure, 2.2% for the saturated liquid density, and 3.2% for the saturated vapor density. The EOS has a reasonable extrapolation behavior from the triple point up to 700 K and 100 MPa. [ABSTRACT FROM AUTHOR]

We theoretically investigate the nucleation of liquid droplets from vapor in the presence of a charged spherical particle. Due to field gradients, sufficiently close to the critical point of the vapor–gas system, the charge destabilizes the vapor phase and initiates a phase transition. The fluid's free energy is described by the van der Waals expression augmented by electrostatic energy and a square-gradient term. We calculate the equilibrium density profile at arbitrary temperatures, particle charges, and vapor densities. In contrast to classical nucleation theory, here, both liquid and vapor phases are different from the bulk phases because they are spatially nonuniform. In addition, the theory applies to both sharp and diffuse interfaces and calculates the surface tension self-consistently. We find the composition profiles and integrate them to get the adsorption near the particle. We find that the adsorption changes discontinuously at a first-order phase transition line. This line becomes a second-order phase transition at high enough temperatures. We describe the transition point numerically and provide approximate analytical expressions for it. Similarly to prewetting, the adsorption diverges at the binodal phase boundary. We construct a phase diagram indicating changes in the binodal, spinodal, and critical temperature. It is shown that the field gradient enlarges the range of temperature and vapor density where liquid can nucleate. [ABSTRACT FROM AUTHOR]

This study evaluates the capability of an unconstrained tomographic algorithm to capture 3D water vapor density variability throughout 2017 in Houston, U.S. The algorithm relies solely on Global Navigation Satellite System (GNSS) observations and does not require an initial guess or other specific constraints regarding water vapor density variability within the tomographic domain. The test domain, featuring 9 km horizontal, 500 m vertical, and 30 min temporal resolutions, yielded remarkable results when compared to data retrieved from the ECMWF Reanalysis v5 (ERA5), regional Weather Research and Forecasting Model (WRF) data, and GNSS-Radio Occultation (RO). For the first time, a time series of Precipitable Water Vapor maps derived from the Interferometric Synthetic Aperture Radar (InSAR) technique was used to validate the spatially integrated water vapor computed by GNSS tomography. Tomographic results clearly indicate the passage of Hurricane Harvey, with integrated water vapor peaking at 60 kg/m2 and increased humidity at altitudes up to 7.5 km. Our findings suggest that GNSS tomography holds promise as a reliable source of atmospheric water vapor data for various applications. Future enhancements may arise from denser and multi-constellation networks.

Based on Microwave Radiometer (MWR) observations in Wuhan over the course of 21 months, we compared the temperature and water vapor levels with those from radiosonde (RS) sounding data at 00:00 and 12:00 UTC, and then analyzed the seasonal and diurnal changes of temperature and water vapor levels from the MWR data. The MWR and RS mean temperatures and dew points are roughly consistent with each other below 2 km, whereas above 2 km, the MWR temperature is slightly lower than the RS temperature. The difference in their water vapor densities decreases quickly with height, and the bias of their relative humidities is generally in the range of −15% to 20%. The MWR observations show that in autumn, the surface temperature is 6.8 K lower during precipitation events than during non-precipitation events, indicating that precipitation in autumn is mainly caused by cold air from the north. The relative humidity during precipitation events exceeds 90% from the ground to 5 km, which is obviously larger than during non-precipitation events. During non-precipitation events, the seasonal mean water vapor density at 0–1.0 km shows an approximately linear increase with the mean temperature; however, their diurnal changes are opposite due to the effect of the boundary layer. At 4.5–5.5 km and 8.5–9.5 km, the mean temperature shows a synchronized diurnal evolution, with the maximum value prior to that at 0–1.0 km, indicating the strong influence of the air–land interaction on the temperature near the ground. Hence, this study is helpful for deepening our understanding of temperature and humidity variabilities over Wuhan. [ABSTRACT FROM AUTHOR]

A fundamental equation of state expressed explicitly in the Helmholtz energy is presented for R-1224yd(Z), an environmentally friendly refrigerant for centrifugal chillers, high-temperature heat pumps, and organic Rankine cycles. The equation of state is based on consistent experimental data for the critical parameters, vapor pressures, saturated liquid and vapor densities, (p , ρ , T) behavior, vapor-phase sound speeds, liquid-phase sound speeds, and ideal-gas isobaric heat capacities. The equation is valid at temperatures from the triple-point temperature (157.8 K) to 473 K and pressures up to 35 MPa. In the valid range, expected relative uncertainties ( k = 2 ) of the equation are 0.04 % for vapor pressures, 0.1 % for saturated liquid densities, 2 % for saturated vapor densities, 0.05 % for liquid densities, 0.3 % for vapor densities, 0.02 % for vapor-phase sound speeds, and 0.04 % for liquid-phase sound speeds, except in the critical region, where more significant uncertainties of up to 2 % are sometimes observed in densities. The equation exhibits reasonable behavior in the critical and extrapolated regions; this is demonstrated by several plots of derived properties over wide ranges of temperature and pressure. [ABSTRACT FROM AUTHOR]

The vacuum arc discharge makes transition to a footpoint mode, anode spot type 1 (type 1) mode and anode spot type 2 (type 2) mode under high current conditions. The mode dependence of the electron and metal vapor densities were experimentally quantified using dichroic Shack–Hartmann type laser wavefront sensors. In the type 1 mode, the electron and metal vapor densities were about 2.5 times higher than the footpoint mode. The electron density of the type 2 mode was three times higher than that of the type 1 mode, while significant difference was not found in the metal vapor density. Such higher electron density for the type 2 mode than the type 1 mode was coherent with a previous result obtained by Stark broadening. The present electron and metal vapor density measurement demonstrated that the amount of the electrode erosion was in the following order: footpoint mode < type 1 mode < type 2 mode, which agreed with a previous study. [ABSTRACT FROM AUTHOR]

Insufficient prior information in GNSS water vapor tomographic models can lead to instability in the structure of the design matrix. The addition of high-precision initial values for water vapor density can effectively solve this problem, but common methods for obtaining water vapor density are relatively crude and not fully utilizing the original accuracy of the a priori water vapor field. To address this issue, a new method is proposed that takes into account the influence of the a priori information weight ratio in the tomographic model on tomographic analysis results, based on the negative exponential decrease of atmospheric water vapor density in the vertical direction with height. Moreover, the 3D water vapor tomographic technique based on the ray-tracing fast voxel traversal algorithm has been improved and implemented in the C++ programming language. To verify the feasibility, accuracy, and stability of the improved 3D water vapor tomographic technique and the proposed method, the experiment using actual data from the CORS station in Hong Kong in January and May and the corresponding grid data provided by ERA5 was conducted. As benchmarks, radio-sounding data from the experimental area was utilized. In May, the proposed method exhibited an average daily improvement in the root mean square error of 0.88 % (UTC0) and 0.97 % (UTC12), and an improvement in the interquartile range of the difference between the water vapor density values at each altitude layer (excluding the top and bottom layers) and the corresponding sounding data of 5.08 % (UTC0) and 3.37 % (UTC12). In January, the average daily improvement in the root mean square error was −13.78 % (UTC0) and −4.84 % (UTC12), and the improvement in the interquartile range of the difference between the water vapor density values at each altitude level and those calculated from the corresponding sounding data was −14.49 % (UTC0) and −6.31 % (UTC12). The results show that the proposed method and the commonly used method maintain high consistency in the accuracy of the water vapor density values solved by the system of tomographic equations and improve stability, especially in May when the water vapor density near the surface is high. The feasibility of the improved 3D water vapor tomographic technique based on the ray-tracing fast voxel traversal algorithm is also demonstrated. [ABSTRACT FROM AUTHOR]

The surface erosion of polyethylene is studied under conditions characteristic of extremely high-rate heating expected in laser-driven and high energy density experiments. A coupled model for photoionization and volumetric photothermal degradation of polyethylene is developed that includes finite rate chemistry and molecular recombination of radicals. First, the model is used to explore the evolution of radicals and hydrocarbons during isochoric heating, for which it is found that polyethylene is not in chemical equilibrium for rates > --> 10 8 K / s. Then, the model is used to explore the cooperativity between photoionization and photothermal ionization during one-dimensional ablation from a pulsed heating source, accounting for coupled energy deposition, thermokinetics, thermochemistry, hydrodynamics, mechanics, and thermal conduction in the ALEGRA multi-physics code. The ablation depth per energy pulse is found to agree with an analytical model for instantaneous energy deposition and absent molecular recombination or photoionization. Otherwise, molecular recombination of radicals reduces the depth of ablation per pulse, owing to thermal stabilization on forming branched molecules. Radical formation through photoionization can be compensated for by recombination, but it accelerates ablation at high enough photoionization rates. Finally, the influence of molecular recombination on the ablation depth is found to decrease for long pulses, owing to decreased recombination reaction rates at lower vapor densities near the ablated surface. These and other findings highlight competition between the processes of scission, recombination, and photoionization during pulsed ablation of polyethylene. [ABSTRACT FROM AUTHOR]

A system of mutually consistent equations describing the pressure , vapor density , and liquid density on the phase equilibrium line of technically important substances in the range from the triple to critical points has been proposed. At the stage of development of this system, the following have been considered: (a) the features of the behavior of a number of properties ( , , , is the average diameter of the saturation line, and is the order parameter) in the critical region; (b) some concepts of the scale theory of critical phenomena and renormalization group theory, which was adapted by Wang L. et al. (2013) for substances with a given molecular structure, including SF6; (c) the Clausius–Clapeyron equation, in which the "apparent" vaporization heat is used instead of the vaporization heat . At the stage of approbation of this system of equations, a method for calculating the adjustable coefficients included in this system using the example of SF6, for which precision data on the thermal properties including the experimental ( , , , ) data are available, has been proposed. Using the proposed technique, the coefficients of the system of equations have been determined using the precision data for SF6 and the calculated values of the SF6 properties in a given temperature range have been obtained. The uncertainty of the calculated data has been statistically analyzed; in particular, the average squared deviations of the experimental ( , , , ) data from the corresponding equations have been found. It has been shown that the proposed system describes the listed properties with less uncertainty than that of the properties corresponding to the original equations of Funke et al. (2001). The temperature dependence of the proposed model satisfactorily agrees with the model developed by Wang et al. (2013) for the SF6 critical region. [ABSTRACT FROM AUTHOR]

Plasmas in contact with liquids can degrade organic molecules in a solution, as reactive oxygen and nitrogen species produced in the plasma solvate into the liquid. Immersing small droplets (tens of microns in diameter) in the plasma can more rapidly activate the liquid compared to treating a large volume of liquid with a smaller surface-to-volume ratio. The interactions between a radio frequency glow discharge sustained in He/H2O and a water droplet containing formate (HCOO−aq) immersed in and flowing through the plasma were modeled using a zero-dimensional global plasma chemistry model to investigate these activation processes. HCOO −aq interacts with OHaq, which is produced from the solvation of OH from the gas phase. The resulting HCOO −aq concentrations were benchmarked with previously reported experimental measurements. The diameter of the droplet, initial HCOO −aq concentration, and gas flow rate affect only the HCOO −aq concentration and OHaq density, leaving the OH density in the gas phase unaffected. Power deposition and gas mixture (e.g. percentage of H2O) change both the gas and liquid phase chemistry. A general trend was observed: during the first portion of droplet exposure to the plasma, OHaq primarily consumes HCOO −aq. However, O2−aq, a byproduct of HCOO −aq consumption, consumes OHaq once O2−aq reaches a critically large density. Using HCOO −aq as a surrogate for OHaq-sensitive contaminants, combinations of residence time, droplet diameter, water vapor density, and power will determine the optimum remediation strategy. [ABSTRACT FROM AUTHOR]

Water vapor plays an extremely important role in the monitoring and prediction of weather, and GNSS tomography can obtain 3D spatiotemporal change information and reliable water vapor profiles. In this paper, an improved global navigation satellite system (GNSS) tropospheric tomography technique using an ERA5 (the fifth generation ECMWF reanalysis) product is developed. First, the ERA5 product was adopted to analyze the spatiotemporal distribution of water vapor, and a water vapor density threshold defining the top of the tomography was determined; then, the height of the grid top (GT) of different seasons was obtained through linear fitting; finally, the water vapor value between GT and tropopause is constrained using the data of the ERA5 product as the initial value. The new method for using the ERA5 product to determine the height of the GT of the tomographic grid reduces the height of the top layer of the grid and increases the number of effective GNSS rays. Data from nine CORS stations in Hong Kong in 2019 were selected for experiments. The results showed that the new algorithm increased the number of effective satellite signals by 14%. In addition, the ERA5 data, the radiosonde data, and the COSMIC‐2 data were used as reference values. The accuracy of the water vapor density obtained by the algorithm was improved by 25%, 17% and 9%, respectively. [ABSTRACT FROM AUTHOR]

The plasma in contact with liquids has led to various novel applications such as plasma biomedicine, material synthesis, and so on. However, the phenomenon of evaporation under plasma treatment and its impact on plasma–liquid interactions has a limited understanding. In this study, the spatially and temporally resolved behavior of water vapor production and its induced influences on plasma properties and gaseous chemistry were studied in detail in an atmospheric pressure pin‐to‐water pulsed He discharge. Diagnostic methods such as laser‐induced fluorescence (LIF) and high‐resolution optical emission spectroscopy (OES) were applied to determine the water vapor and OH radical densities, as well as key plasma parameters such as the gas temperature and electron density. It shows that the physicochemical properties of plasma vary among different discharge regions due to evaporation behavior stimulated during the pulsed discharge‐on phase. In addition, using simulation based on the experimental data, the mechanisms of how water vapor affects the observed spatiotemporal behaviors of OH radicals in different discharge regions are understood. Compared to the pin‐anode and liquid‐cathode sheath regions, proper electron parameters such as density and temperature, as well as water vapor density in the plasma‐positive column, significantly enhance the production of reactive OH radical through the dominant path of electron‐stimulated H2O dissociation. However, higher levels of electron parameters in the intense discharge region near the positive‐pin boundary enhance OH dissociation and finally result in the hollow distribution of OH density. From the global kinetic plasma simulation, the production of reactive hydroxide species playing key roles in plasma medicine treatments, such as O, H, HO2, H2O2, and hydrated ions including H+(H2O)4 and H+(H2O)5, are promoted noticeably as a result of the enhanced water evaporation process. [ABSTRACT FROM AUTHOR]

Measuring the internal dynamic temperature of alkali metal vapor cells is crucial for enhancing the performance of numerous atomic devices. However, conventional methods of measuring the internal dynamic temperature of the cell are prone to errors. To obtain a more accurate internal dynamic temperature of the alkali metal vapor cell, a temperature measuring method based on the data fusion of the Kalman filter has been proposed. This method combines the indirect temperature measurement signal from a resistance temperature detector with the atomic absorption spectrometric temperature measurement signal. This provides a high-accuracy set of internal dynamic temperatures in the cell. The atomic vapor density calculated from the final fusion results is 37% average lower than that measured by external wall temperature measurements, which is in line with the conclusions reached in many previous studies. This study is highly beneficial to measure the temperature of alkali metal vapor cells. [ABSTRACT FROM AUTHOR]

This work presents a fundamental equation of state for the thermodynamic properties of R-1336mzz(E). The equation of state is expressed explicitly in the Helmholtz energy with temperature and density as the independent variables, and is based on consistent experimental datasets, including the critical parameters, vapor pressure, saturated liquid and vapor densities, (p , ρ , T) behavior, vapor phase sound speed, and ideal-gas isobaric heat capacity. The equation of state is valid for temperatures from 200.15 K to 410 K and pressures up to 5.7 MPa. In this range, expected relative uncertainties at the 95 % confidence interval ( k = 2 ) are 0.1 % for vapor pressures, 1 % for saturated liquid densities, 1 % for saturated vapor densities, 0.15 % for liquid densities, 0.5 % for vapor densities, and 0.05 % for vapor phase sound speeds, except in the critical region where larger uncertainties of up to 2 % are sometimes observed in densities. The equation exhibits reasonable behavior in the critical and extrapolated regions; this is demonstrated by several plots of derived properties over wide ranges of temperature and pressure. Through the use of the new equation of state, this work also formulates an extended corresponding states (ECS) model for the viscosity and thermal conductivity of R-1336mzz(E) to represent recent experimental data for these properties mostly within their uncertainties. [ABSTRACT FROM AUTHOR]

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The present work uses molecular dynamics simulation to investigate the phase transition phenomena, saturated vapor-liquid density, shear viscosity, isobaric heat capacity, and velocity auto correlation function of low GWP refrigerants R448A and R449A at various temperatures. The phase change behavior of the refrigerants is investigated through the density profile and potential energy distribution; the dynamical behavior is examined according to the condensate period, molecular aggregation in the trajectory, and velocity auto correlation function of the condensed particles. The results show that increasing the condensing temperature from 233.15 K to 308.15 K leads to slow phase transitions for both R448A and R449A. The liquid density of R448A decreases to 19.21 % and its vapor density increases to 13.07 %, while the liquid density of R449A decreases to 19.59 % and its vapor density increases to 12.64 % due to the increase of temperature from 233.15 K to 308.15 K. Particle snapshots reveal that vapor molecules underwent a quick phase transition to subcooled liquid during a certain condensing time period. Subcritical clusters of both R448A and R449A refrigerant molecules are shaped in the initial part of the simulations, and then aggregate to produce critical condensate nuclei over time. [ABSTRACT FROM AUTHOR]

Fluid ammonia is highly associated because of strong intermolecular hydrogen bonding. This causes different behavior of thermophysical properties from nonpolar fluids, as reflected, for example, in the heat capacity. In this work, a new equation of state explicit in the Helmholtz energy with independent variables of temperature and density was developed, which includes a new associating term. Its uncertainties in density, vapor pressure, saturated liquid and vapor densities, and caloric properties were estimated by comparisons with experimental data. The new equation of state is valid from the triple-point temperature (195.49 K) to 725 K at pressures up to 1000 MPa and densities up to 53.13 mol dm−3. Physically correct behavior within the region of validity and at extremely high temperatures and pressures, and at temperatures far below the triple-point temperature, was obtained by applying constraints on various properties. The unique physical behavior of ammonia shown in some thermodynamic properties is described in detail, which will provide a preliminary template for developing equations of state for other associating fluids. [ABSTRACT FROM AUTHOR]

We use molecular dynamics to determine the mass accommodation coefficient (MAC) of water vapor molecules colliding with a rapidly moving liquid-vapor interface. This interface mimics those present in collapsing vapor bubbles that are characterized by large interfacial velocities. We find that at room temperature, the MAC is generally close to unity, and even with interfaces moving at 10 km/s velocity, it has a large value of 0.79. Using a simplified atomistic fluid model, we explore the consequences of vapor molecule interfacial collision rules on pressure, temperature, and density of a vapor subjected to an incoming high-velocity liquid-vapor interface. [ABSTRACT FROM AUTHOR]

This paper presents time and space resolved results of spectroscopic measurements in a vacuum circuit breaker experiment during high-current anode modes, i.e., anode spot type 1, anode spot type 2, and anode plume. Excited state densities for Cu I, Cu II, and Cu III transitions are determined during anode spot type 1 and type 2 as well as for the anode plume. Temporal evolution of excited state densities and Cu neutral gas densities are also determined during anode spot type 1 and type 2, which show that the Cu density in front of the anode during anode spot type 2 is about 6 times higher compared to anode spot type 1. Electron densities are also determined during both types of anode spot using Stark broadening. The electron densities during anode spot type 2 are remarkably higher than during anode spot type 1. [ABSTRACT FROM AUTHOR]

The temperature of the alkali metal cell, which affects the density of the alkali-metal vapor and the gas pressure, is usually difficult to measure directly. However, the temperature of the alkali-metal cell and the density of the alkali-metal vapor are important parameters that affect the performance of the atomic sensor. In this paper, a device that can directly measure the internal temperature of an alkali metal cell in real time is designed for the first time to explore the relationship between alkali-metal vapor density and temperature. Alkali-metal vapor density is measured using the absorption spectrum. The pressure broadening model, combined with the transition of four hyperfine levels, was used to fit the absorption line of 87Rb D1 under the action of 700 Torr N2, and a good fitting effect was obtained. The experimental results show that the density of 87Rb is less than the value calculated by the empirical formula. Based on the experimental results, we give the calculation formula of 87Rb density with an uncertainty of only 4% and obtain the temperature dependence index of the line width and linear displacement of 87Rb in N2 by analyzing the absorption spectrum. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrogel-based evaporative cooling with a low carbon footprint is regarded as a promising technology for thermal regulation. Yet, the efficiency of hydrogel regeneration at night generally mismatches with vapor evaporation during the day, resulting in a limited cooling time span, especially in arid regions. In this work, we propose an efficient approach to improve hydrogel cooling performance, especially the cooling time span, with a bilayer structure, which comprises a bottom hydrogel layer and an upper aerogel layer. The microporous aerogel layer can reduce the saturation vapor density at the hydrogel surface by employing daytime radiative cooling, together with increased convective heat transfer resistance by thermal insulation, thus boosting the duration of evaporative cooling. Specifically, the microstructure of porous aerogel for efficient radiative cooling and vapor transfer is synergistically optimized with a cooling performance model. Results reveal that the proposed structure with a 2-mm-thick SiO2 aerogel can reduce the temperature by 1.4 °C, meanwhile extending the evaporative cooling time span by 11 times compared to a single hydrogel layer. [ABSTRACT FROM AUTHOR]

The New York State Mesonet (NYSM) Profiler Network consists of 17 stations statewide. Each station operates a ground-based Doppler lidar (DL), a microwave radiometer (MWR), and an environmental Sky Imaging Radiometer (eSIR) that collectively provide profiles of wind speed and direction, aerosol, temperature, and humidity along with solar radiance, optical depth parameters, and fisheye sky images. This study presents a multi-year, multi-station evaluation of Profiler Network data to determine the robustness and accuracies of the instruments deployed with respect to well-defined measurements. The wind speed (WS) measured by the DL and temperature (T) and water vapor density (WVD) measured by the MWR at three NYSM Profiler Network sites are compared to nearby National Weather Service radiosonde (RS) data, while the aerosol optical depth (AOD) measured by the eSIR at two Profiler Network sites are compared to nearby in situ measurements from the Aerosol Robotic Network (AERONET). The overall comparison results show agreement between the DL or MWR and RS data with a correlation of R2≥0.89 and a correlation between AERONET and eSIR AOD data of R2 ≥ 0.78. The WS biases are statistically insignificant and equal to 0 (p > 0.05) within 3 km, whereas T and WVD biases are statistically significant and are below 5.5 ∘ C and 1.0 g m -3 , within 10 km. The AOD biases are also found to be statistically significant and are within 0.02. The performance of the DL, MWR, and eSIR are consistent across sites with similar error statistics. When compared during three different weather conditions, the MWR is found to have varying performance, with T errors higher during clear-sky days, while WVD errors are higher during cloudy and precipitation days. To correct such observed biases, a linear regression method was developed and applied to the MWR data. In addition, wind shear from the DL and 14 common thermodynamic parameters derived from the MWR show an agreement with RS values where correlation is mostly R2 ≥ 0.70 and biases are mostly statistically insignificant. A case study is presented to demonstrate the applicability of DL and MWR for nowcasting a severe weather event. Overall, this study demonstrates the robustness and value of the Profiler Network for real-time weather operations. [ABSTRACT FROM AUTHOR]

When exposed to sufficiently humid environments, pollen grains burst and release large quantities of small subpollen particles (SPPs) which carry ice nucleating macromolecules. In this study, for the first time we develop a physically based parameterization describing the bursting process of pollen by applying a turgor pressure parameterization and quantify the impact SPPs have on overall ice nucleation in clouds. SPPs are generated from simulated birch pollen emissions over Europe for a 10‐day case study in spring. We found SPP concentrations to surpass pollen grain concentrations by 4–6 orders of magnitude leading to an abundance of biological ice nuclei from SPPs in the range of 103−104 m−3. However, it is found that these concentrations lead to only small changes in hydrometeor number densities and precipitation. Addressing the question when SPPs become relevant for ice nucleation in clouds, we conducted a sensitivity investigation. We find that amplifying ice nucleation efficiency of biological particles by factors greater 100 increases the ice particle numbers by up to 25% (T ≈ 268 K). Strong reductions show in cloud droplet number concentration and water vapor at these temperatures while water vapor is increasing at 600 m. Overall, we found a net reduction of water in the atmosphere as liquid and particularly water vapor density is reduced, while frozen water mass density increases above 257 K. Findings indicate an alteration of mixed‐phase cloud composition and increased precipitation (up to 6.2%) when SPPs are considered as highly efficient biological ice nuclei. Key Points: Subpollen particles (SPPs) reach freezing altitudes in large number concentrationsNucleation efficiency of SPPs affects both amplitude and sign of impact on nucleation processesRelevant impact requires greatly increased nucleation efficiency of the SPPs [ABSTRACT FROM AUTHOR]

For better modeling the vertical distribution and variations of water vapor, a 10-year time-series of a newly derived water vapor parameter (termed IRPWV), defined as the ratio of water vapor density (WVD) to the total precipitable water vapor (TPWV), was statistically analyzed. This research showed that the vertical distribution of IRPWV presents a periodic pattern and is highly correlated with the relative magnitude of its corresponding TPWV when compared with the other TPWVs in the same time range. Six TPWV ranges were first chosen to determine the relative magnitude and then used to classify the IRPWV vertical distributions of TPWV. For the periodic variations in each of the six classified IRPWV vertical distribution time-series, a temporal IRPWV model was developed accordingly with six sets of coefficients. The new models were validated by comparing their predictions against the reference values from sounding data at 12 radiosonde stations in China, and their performance was also evaluated against that of the commonly used exponential model. Results showed that, first, the proportions of the height range that had reduced annual root mean square error (RMSE) of WVD in all height ranges within all TPWV ranges were over 75% at the 12 stations. Then, the annual RMSEs of the WVD for all the stations were reduced by at least 11%, 20%, 43%, 48%, 40%, 38%, 32%, 35%, 32%, and 28% in each of the 10 selected height ranges, respectively. [ABSTRACT FROM AUTHOR]

Concentration distribution is essential for the emergency disposal of cryogenic fuel leakage. In the dispersion process of cryogenic gas, its concentration is greatly influenced by the atmospheric water vapor. The authors have presented an adiabatic mixing model to derive the concentration of the cryogenic gas, in which the value of water vapor density is obtained by referring to the NIST database continuously. However, it is difficult to achieve fast system response times for real-time monitoring systems when calling NIST. Thus, a simple algebraic model of water vapor density with high calculation efficiency is necessary. Based on the detection of temperature and the solution of water vapor partial pressure, a calculation model was developed. For a given initial ambient temperature and relative humidity, the dew point could be solved by Qian's correlation. By temperature comparisons of the mixture cloud, dew point, and triple point, the water vapor partial pressure can be calculated by the Goff–Gratch formulation. Then, the water vapor density during the temperature declining process can be derived via EOS. The results show that the model has high estimation accuracy, and has a close mean deviationof 0.08%to the IAPWS 95 of 0.03%. The increase in the computation efficiency was confirmed as +67% under nine testing points. The model facilitates the engineering utilization of the adiabatic mixing model for cryogenic fuel leakage monitoring. [ABSTRACT FROM AUTHOR]

An empirical equation of state in terms of the Helmholtz energy is presented for n-octane. It is valid from the triple-point temperature 216.37 K to 650 K with a maximum pressure of 1000 MPa and allows for the calculation of all thermodynamic properties in the vapor and liquid phase, in the supercritical region, and in equilibrium states. In the homogeneous liquid phase, the uncertainty in density is 0.03% at atmospheric pressure. For pressures up to 200 MPa and temperatures between 270 and 440 K, density is described with an uncertainty of 0.1%. Outside this region, the uncertainty in the liquid phase increases to 0.5%. Densities in the vapor phase are estimated to be accurate within 0.5%. The uncertainty in vapor pressure depends on the temperature range and varies from 0.02% to 0.4%. Speed of sound in the liquid phase at temperatures below 500 K is described with an uncertainty of 0.1% or less. The isobaric heat capacity in the liquid phase can be calculated with an uncertainty of 0.1% and in the gas phase with 0.2%. A reasonable physical behavior of the equation of state was ensured by the analysis of numerous thermodynamic properties. [ABSTRACT FROM AUTHOR]

• An original model was constructed using the second law of thermodynamics. • A simplified model and algorithm that satisfies thermodynamic consistency were proposed. • The novel numerical model can reduce the spurious velocity on the interface and simulate liquid-vapor transition at higher liquid/vapor density ratios, which can reach 6776:1. • Low saturation temperature pool boiling with and without soluble surfactants was also studied. Despite the enormous potential in facilitating natural development and migration of interfaces during multiphase simulation, the phase-field method remains restricted to low-density ratios, owing to inherent thermodynamic inconsistency, especially for multiphase flow systems with surfactants. The present paper first constructs a liquid-vapor phase transition phase-field model with soluble surfactants using the second law of thermodynamics as the original model. Then, a simplified liquid-vapor phase transition model with soluble surfactants that satisfies thermodynamic consistency is proposed to simulate pool boiling at higher-density ratio. A novel numerical algorithm for the simplified model that satisfies semi-discrete thermodynamic consistency is also developed. Compared with the original model, the thermodynamically consistent characteristics of the simplified numerical model proposed in this paper can significantly reduce the spurious velocity on the interface of a static droplet and thus enable the numerical model to simulate liquid-vapor transition at higher liquid/vapor density ratios. Vapor-liquid coexistence, Laplace's law, and multiple bubble coalescence are used to validate the accuracies and effectiveness of the mathematical model and numerical algorithm. The liquid/vapor density ratio can reach 6776:1 under saturation temperature 0.3 T c (T c is the critical temperature). The approach is then used to model pool boiling at a low saturation temperature (0.5 T c) with and without soluble surfactants, significantly lower than reported in comparable literature. The results demonstrate that surfactants significantly influence the dynamics of bubbles, and a critical concentration can be identified. In addition, soluble surfactants can also suppress coalescence between adjacent bubbles and prevent the formation of larger bubbles during pool boiling. [ABSTRACT FROM AUTHOR]

In this work, we propose and test the validity of a phase-field method tailored specifically for modeling boiling phenomena. The method relies on numerical solutions of the Navier–Stokes equations coupled with a phase-field method and the energy equation. The continuity and Navier–Stokes equations have been modified introducing a source term that accounts for phase change. Likewise, in the conservative Allen–Cahn equation (phase-field method) a source term that accounts for the volume is introduced. The system of governing equations is solved using a projection-correction method and equations are discretized using a second-order finite difference approach. Thanks to the numerical discretization employed, a constant coefficient Poisson equation for pressure is obtained, which can be efficiently solved using FFT-based direct solvers. The proposed method is validated against several benchmarks: an interface undergoing vaporization at a constant rate, the Stefan problem, the adsorption problem, and the growth of a 2D vapor bubble. For all the benchmarks, the present method well matches with analytical and archival literature results for a wide range of vapor-to-liquid density ratios, from ρv/ρl=1\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\rho _v/\rho _l = 1$$\end{document} down to ρv/ρl≃5×10-4\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\rho _v/\rho _l \simeq 5 \times 10^{-4}$$\end{document} (where ρv\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\rho _v$$\end{document} identifies the vapor density and ρl\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\rho _l$$\end{document} the liquid density). [ABSTRACT FROM AUTHOR]

The constant-temperature θ(t) thermal decay discriminates the performance of the quasisolid water from that of the saturated NaCl supersolid solution, unveiling the respective O:H–O bond relaxation dynamics. [Display omitted] • O:H–O bond specific-heats disparity entitles the quasisolidity of negative thermal expansivity. • The H–O contracts ∼10 % in the supersolid phase owing to electrification and undercoordination. • Polarization drives the supersolid phase with the ω H shifting from 3200 to 3450 cm−1. • The viscoelastic, hydrophobic supersolid is less dense, more thermally diffusive, and stabler. This work features the recent findings of the quasisolid (QS, or quasi-liquid) in the temperature domain and supersolid due to electric polarization or molecular undercoordination, which are beyond the scope of the P-T phase diagram. The cooperativity of the coupling O:H–O bond in its segmental length, energy, specific heat, and associated polarization derive these abnormal phases. The specific-heat disparity defines structure phases varying from XI to Vapor and mass density evolution under ambient pressure. Possessing negative thermal expansivity (NTE), the QS phase transfers the liquid to the solid phase, which fosters ice buoyancy. The supersolid phase presents in the skin of water, ice, and droplets, and the ionic hydration cells and volumetric water with a current flow or under ∼106 eV/cm electric bias. The H–O bond of the supersolid phase is 8 ∼ 10 % shorter and vibrating at frequencies 7.3 % higher than that of the standard pristine water (0.1 nm in length and 3250 cm−1 in frequency). The supersolid has extraordinary elasticity, mechanical strength, optical reflectivity, structure order, thermal stability and diffusivity, catalytic capability, and chemical reactivity but 25 % lower mass density. The gel-like supersolidity endows ice and water with high hydrophobicity, viscoelasticity, catalytic and hydro-voltaic capability, and thermal diffusivity. The H–O bond contracts and absorbs energy during the Liquid-QS-Ice phase transition while doing contrastingly in the supersolid phase of the saturated NaCl solution under 254 K temperature. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a novel, adapted approach for computing gas adsorption properties in porous materials. Our methodology is based on the Dubinin-Polanyi's adsorption model, and we investigate various frameworks to estimate its required essential components and prediction capabilities. The required components are linked to the physicochemical properties of the adsorbates, such as the vapor saturation pressure and density in the adsorbed phase. To conduct this analysis, we obtain adsorption isotherms for several metal–organic frameworks encompassing a range of pore sizes, shapes, and chemical compositions. We then apply and evaluate multiple combinations of models for saturation pressure and density. After the evaluation of the methods, we propose a working thermodynamic model for computing adsorption isotherms, which entails using the critical isochore as an approximation of the saturation pressure above the critical point and applying Hauer's method with a universal thermal expansion coefficient for density in the adsorbed state. This framework is applicable not only to simulated isotherms but also to experimental data from the literature for various molecules and structures of different natures, demonstrating robust predictive capabilities and high transferability. Our method showcases superior performance in terms of accuracy, generalizability, and simplicity compared to existing methods currently in use. In light of our results, this method, starting from a single adsorption curve and based on physically interpretable parameters, can predict adsorption properties across a wide range of operating conditions. [Display omitted] • The adsorption potential theory can be used for predicting adsorption isotherms. • A combination of adsorbed density and vapor pressure is key to the predictive theory. • The predictive capabilities of the proposed framework are successfully tested. • Equations of state are alternative options to obtain vapor saturation pressure. [ABSTRACT FROM AUTHOR]

• An artificial intelligence-based (AI) analysis of a multi-vane expander was done. • Isentropic internal efficiency was observed and predicted in this investigation. • AI prediction used pressure ratio, density ratio, vapor quality, and other parameters. • The validation used experimental data from a retrofitted organic Rankine cycle (ORC). • Vapor quality in an ORC system was measured using capacitive sensors. This study delves into experimental research on a retrofitted organic Rankine cycle (ORC), focusing on the performance of the expansion process near saturated vapor states (from two-phase to superheated conditions). A multi-vane expander was selected for its relevance in small-scale partially evaporated ORC. Several sensors were installed to monitor key parameters, including pressure, temperature, vapor quality, and rotational speed of the expander. The results show that the isentropic efficiency spans a range of 0.37 to 0.49. This variability was observed within an inlet vapor quality of 0.93–0.98, pressure ratios ranging from 5.67 to 10.67, and density ratios ranging from 7.4 to 13.3. In response to the challenge of time-consuming experiments and identification, this research employed deep learning techniques to predict the isentropic efficiency. Two different prediction scenarios were explored: one based on pressure ratio and the other based on density ratio. The results show that predictions based on density ratio offer better accuracy for isentropic efficiency compared to those based on pressure ratio. Three different scenarios for prediction were explored: initially utilizing two input parameters (density ratio and vapor quality), which show root mean squared error (RMSE) and coefficient of determination (R 2) values in the ranges of 0.0136–0.0148 and 0.5832–0.6474, respectively. Subsequent enhancements were achieved by introducing inlet temperature as a third input parameter, improving performance with RMSE of 0.0033–0.0034 and R 2 of 0.9780–0.9793. Moreover, incorporating rotational speed as a fourth input parameter, the prediction was performed with nearly similar RMSE and R 2 values compared to using only three input parameters; it significantly reduces computing times in some cases, achieving speeds relatively 2.25–49.70% faster. This approach demonstrated a well-fitted line and an accurate performance map, establishing its effectiveness in predicting isentropic efficiency. [ABSTRACT FROM AUTHOR]

Ice habit diagrams published prior to 2009—and many since—do not accurately describe in situ observations of ice shapes as a function of temperature and moisture. Laboratory studies and analysis of field observations by Bailey and Hallett in a series of papers in 2002, 2004, and 2009 corrected several errors from earlier studies, but their work has not been widely disseminated. We present a new, simplified diagram based on Bailey and Hallett's work that focuses on several ice growth forms arising from the underlying surface processes by which mass is added to a crystal: tabular, columnar, branched, side branched, two types of polycrystalline forms, and a multiple growth regime at low ice supersaturations. To aid interpretation for a variety of applications, versions of the ice growth diagram are presented in terms of relative humidity with respect to water as well as the traditional formats of relative humidity with respect to ice and vapor density excess. These diagrams are intended to be understandable and useful in classroom settings at the sophomore undergraduate level and above. The myriad shapes of pristine snow crystals can be described as the result of either a single growth form or a sequence of growth forms. Overlays of data from upper-air soundings on the ice growth diagrams aid interpretation of expected physical properties and processes in conditions of ice growth. [ABSTRACT FROM AUTHOR]

Cloud droplet nucleation is classically defined as a droplet growing to a size such that its ambient supersaturation exceeds its surface equilibrium water vapor pressure. Unactivated particles are always in equilibrium with the ambient vapor pressure. Further studies showed that such an equilibrium assumption leads to many more cloud droplets being nucleated due to neglecting kinetic growth limitations, including the inertial mechanism, evaporation mechanism, and deactivation mechanism. Moreover, the inertial mechanism results in great discrepancy between the actual size and the critical size of nucleation for large aerosol particles. These issues complicate cloud droplet nucleation parameterization for applications in cloud modeling. To establish a physically based nucleation scheme, we established a highly size-resolved Lagrangian parcel model. Vapor diffusion and heat conduction were calculated according to Maxwell theory, and the surface vapor density and temperature were explicitly simulated. The surface temperature variation of a droplet with its size was considered. The surface supersaturation of a droplet, taking into account the surface temperature variation, is different from its equilibrium supersaturation at its large sizes. The nucleation simulation showed that the inertial and deactivation mechanisms can impact droplet nucleation. Moreover, very large nuclei can trigger rain embryo formation in a short time period. Even though there are kinetic limitations, the classical equilibrium assumption can be applied to determine the primary nucleation number of cloud droplets. Meanwhile, a regression formula for the size of a nucleated droplet and its dry aerosol size was established. [ABSTRACT FROM AUTHOR]

Three SAFT equations of state: sPC-SAFT, Soft-SAFT and SAFT-BACK were fitted to five Hydrofluoroethers (HFEs): four perfluoroalkyl methyl ethers and one C6-fluoroketone. The fits were verified with experimental data consisting of vapor pressure, liquid and vapor density and the speed of sound. Two sets of PC-SAFT parameters for HFE fluids from the literature were also tested and compared with our results. The selected fluids are good candidates to replace perfluorocarbon heat transfer fluids, and the obtained fits are intended to support the challenging transition of cooling systems to more environment-friendly fluids. The SAFT equations of state coupled with group contribution methods enable mixtures of a multitude of compounds to be modeled and their equilibrium, solubility, absorption and other effects to be predicted. This can be helpful not only when studying the properties of useful mixtures but also when evaluating material compatibility and the effects of fluid contamination, which cause a lot of concern for cooling systems that require very high reliability. [ABSTRACT FROM AUTHOR]