Liquid Water Research Articles

Predicting the Structure of Enzymes with Metal Cofactors: The Example of [FeFe] Hydrogenases.

The advent of deep learning algorithms for protein folding opened a new era in the ability of predicting and optimizing the function of proteins once the sequence is known. The task is more intricate when cofactors like metal ions or small ligands are essential to functioning. In this case, the combined use of traditional simulation methods based on interatomic force fields and deep learning predictions is mandatory. We use the example of [FeFe] hydrogenases, enzymes of unicellular algae promising for biotechnology applications to illustrate this situation. [FeFe] hydrogenase is an iron-sulfur protein that catalyzes the chemical reduction of protons dissolved in liquid water into molecular hydrogen as a gas. Hydrogen production efficiency and cell sensitivity to dioxygen are important parameters to optimize the industrial applications of biological hydrogen production. Both parameters are related to the organization of iron-sulfur clusters within protein domains. In this work, we propose possible three-dimensional structures of Chlorella vulgaris 211/11P [FeFe] hydrogenase, the sequence of which was extracted from the recently published genome of the given strain. Initial structural models are built using: (i) the deep learning algorithm AlphaFold; (ii) the homology modeling server SwissModel; (iii) a manual construction based on the best known bacterial crystal structure. Missing iron-sulfur clusters are included and microsecond-long molecular dynamics of initial structures embedded into the water solution environment were performed. Multiple-walkers metadynamics was also used to enhance the sampling of structures encompassing both functional and non-functional organizations of iron-sulfur clusters. The resulting structural model provided by deep learning is consistent with functional [FeFe] hydrogenase characterized by peculiar interactions between cofactors and the protein matrix.

Numerical simulation of gradient catalyst layer design in proton exchange membrane water electrolyzer with enhanced performance

The catalyst loading, ionomer content and agglomerate radius in the catalyst layer (CL) of proton exchange membrane water electrolyzer (PEMWE) plays critical role on its electrochemical performance. Conventionally, the CL in PEMWE is modeled with uniform composition and homogeneous domain. In this study, a two-dimensional PEMWE model considering linear gradient distribution of catalyst, ionomer and agglomerate radius in CL was developed and their effect on the electrolyzer performance were systematically investigated. The results show that, when the total catalyst, ionomer loading and the average agglomerate radius in CL are kept constant, the optimum PEMWE performance was achieved with low catalyst loading, high ionomer content, and small agglomerates radius distribution at the CL-PEM interface. Compared with the uniform CL, this optimized gradient CL design results into a 7.01% improvement in the PEMWE current density. Meanwhile, under the gradient CL design, increased maximum temperature and oxygen concentration with lower liquid water saturation is found inside PEMWE, which might affect the temperature distribution uniformity within the PEMWE. The results of this work provide insightful guidance for the CL optimization design of PEMWE.

On Local Structure Equilibration of Ca2+ in Solution by Ab Initio Molecular Dynamics.

Analyzing the stable isotopic ratio of Ca offers valuable insights into a wide range of applications from climate reconstruction to bone cancer diagnosis and agricultural nutrient improvement. While the first hydration shell of Ca in solution is expected to play a major role in its fractionation properties, the coordination of Ca in water remains a subject of debate. In this work, Ca2+ in water has been modeled by means of ab initio molecular dynamics simulations using various exchange and correlation functionals and at different temperatures. Results show a significant effect of the functional on the average Ca2+ coordination, depending on its tendency to over- or understructure liquid water. The BLYP functional with Grimme-D2 correction was judged as the most accurate among those tested based on its accuracy to reproduce water structural and diffusion properties. Using this functional, the effect of temperature has been systematically investigated, focusing on means to limit the uncertainty in our assessments of the average coordination of Ca2+ ions by (1) estimating the number of water exchanges in the simulations and (2) implementing a statistical approach based on Markov chains. The findings indicate, especially, that our simulations at 300, 350, and 400 K do not yield converged results due to potential equilibration problems. These observations impose substantial constraints on the trustworthiness of numerous estimates in the existing literature that depend on trajectories with insufficient exchanges. We estimate Ca2+ coordination values of 6.8 ± 0.1, 6.8 ± 0.1, 6.7 ± 0.2, and 6.7 ± 0.2 at 600, 550, 500, and 450 K respectively. At lower temperatures (300, 350, and 400 K), while obtaining definitive values for Ca2+ coordination remains challenging, our research does indicate a potential temperature-related influence on coordination with an average Ca2+ coordination at 300 K as low as 6.2.

Modelling atmospheric behaviour over southern West Africa using RegCM 4.7.1: Case assessment of relative humidity and zonal wind profiles based on the 2016 DACCIWA summertime field campaign

In this paper, we present an analysis of summertime atmospheric simulation (June–July 2016) for southern West Africa (sWA) using the RegCM 4.7.1 regional climate model to describe the atmospheric behaviour over the region, and also engage comparisons between the modelled data and observed upper air data acquired during the DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) field campaign period. First, assessments of relative humidity and zonal wind profiles were made for selected coastal and inland stations, to infer the relative vertical and temporal atmospheric differences for both locations. Thereafter, the model’s performance was evaluated, capturing an excessive wet bias in RH profiles of the model with accompanying reduced zonal winds at the Tropical Easterly Jet (TEJ) region and thus produces excessive upper tropospheric cloud liquid water content. Also, in the lower troposphere (particularly, the monsoon layer), RegCM 4.7.1 model captures adequate spatial differences in both RH and zonal wind profiles along the coast and inland. We judge this outcome to be a valuable contribution on the path to rendering RegCM4 a good tool for simulating atmospheric and climate dynamics in sWA.

Sodium acetate-based thermochemical energy storage with low charging temperature and enhanced power density

The electrification of heat necessitates the development of innovative domestic heat batteries to effectively balance energy demand with renewable power supply. Thermochemical heat storage systems show great promise in supporting the electrification of heating, thanks to their high thermal energy storage density and minimal thermal losses. Among these systems, salt hydrate-based thermochemical systems are particularly appealing. However, they do suffer from slow hydration kinetics in the presence of steam, which limits the achievable power density. Additionally, their relatively high dehydration temperature hinders their application in supporting heating systems. Furthermore, there are still challenges regarding the appropriate thermodynamic, physical, kinetic, chemical, and economic requirements for implementing these systems in heating applications. This study analyzes a proposal for thermochemical energy storage based on the direct hydration of sodium acetate with liquid water. The proposed scheme satisfies numerous requirements for heating applications. By directly adding liquid water to the salt, an unprecedented power density of 5.96 W/g is achieved, nearly two orders of magnitude higher than previously reported for other salt-based systems that utilize steam. Albeit the reactivity drops as a consequence of deliquescence and particle aggregation, it has been shown that this deactivation can be effectively mitigated by incorporating 10 % silica, achieving lower but stable energy and power density values. Furthermore, unlike other salts studied previously, sodium acetate can be fully dehydrated at temperatures within the ideal range for electrified heating systems such as heat pumps (40 °C – 60 °C). The performance of the proposed scheme in terms of dehydration, hydration, and multicyclic behavior is determined through experimental analysis.

Constraints on Southern Ocean Shortwave Cloud Feedback From the Hydrological Cycle

AbstractShifts in Southern Ocean (SO, 40–85°S) shortwave cloud feedback (SWFB) toward more positive values are the dominant contributor to higher effective climate sensitivity (ECS) in Coupled Model Intercomparison Project Phase 6 (CMIP6) models. To provide an observational constraint on the SO SWFB, we use a simplified physical model to connect SO SWFB with the response of column‐integrated liquid water mass (LWP) to warming and the susceptibility of albedo to LWP in 50 CMIP5 and CMIP6 GCMs. In turn, we predict the responses of SO LWP using a cloud‐controlling factor (CCF) model. The combination of the CCF model and radiative susceptibility explains about 50% of the variance in the GCM‐simulated SWFB in the SO. Observations of SW radiation fluxes, LWP, and CCFs from reanalysis are used to constrain the SO SWFB. Observations suggest a SO LWP increase in response to warming and albedo susceptibility to LWP that is on the lower end relative to GCMs. The overall constraint on the contribution of SO to global mean SWFB is −0.168 to +0.051 W m−2 K−1, relative to −0.277 to +0.270 Wm−2 K−1. In summary, observations suggest SO SWFB is less likely to be as extremely positive as predicted by some CMIP6 GCMs, but more likely to range from moderately negative to weakly positive.

Studying the air ventilation effect on the hydromechanical behaviour of cracked rock media around large-scale gallery using a double-scale FE2 model

The interaction between rock and the atmosphere occurs through air circulation within underground galleries, thereby affecting the hydromechanical long-term behaviour of the rock in the vicinity of galleries and its drainage. To study this air-rock interaction, a coupled hydromechanical model within a double-scale finite element framework is improved to simulate partial saturated cases at small scale in the crack network. The capillary water distribution at the microscale is not modelled. The introduction of the capillary pressure is therefore realised from a macroscopic phenomenon consideration, but it depends on the evolution of the mesoscopic structure and geometry (as the normal opening of mineral contacts) inside 2D Representative Elementary Areas. The gas flow is also neglected by assuming a constant gas pressure. Then, the developed model is applied to model an underground gallery ventilation process, which is reproduced with constant air relative humidity inside the gallery and classical imposition at the gallery wall. The numerical simulation results show that long-term gallery air ventilation induces a drainage of the liquid water present in the rock towards the gallery that leads to an obvious desaturation process close to the gallery wall. Furthermore, the gallery air ventilation inhibits the development of shear strain localisation around the gallery.

Experimental and Numerical Simulation Study of Oxygen Transport in Proton Exchange Membrane Fuel Cells at Intermediate Temperatures (80 °C-120 °C).

Investigating the oxygen transport law within the Membrane Electrode Assembly at intermediate temperatures (80-120 °C) is crucial for enhancing fuel cell efficiency. This study analyzed the resistance to oxygen transport within the Membrane Electrode Assembly at intermediate temperatures using limiting current density and electrochemical impedance spectroscopy. The study findings reveal that, as temperature progressively increases, the Ostwald ripening effect leads to a 34% rise in the local oxygen transport resistance (Rlocal) in relation to the pressure-independent resistance (Rnp) within the cathode catalytic layer. Concurrently, the total transport resistance (Rtotal) decreases from 27.8% to 37.5% due to an increase in the gas diffusion coefficient and molecular reactivity; additionally, there is a decrease in the amount of liquid water inside the membrane electrode. A three-dimensional multiphysics field steady-state model was also established. The model demonstrates that the decrease in oxygen partial pressure can be mitigated effectively by increasing the back pressure at intermediate temperatures to ensure the cell's performance.

3D simulations of TRAPPIST-1e with varying CO2, CH4, and haze profiles

ABSTRACT Using a 3D General Circulation Model, the Unified Model, we present results from simulations of a tidally locked TRAPPIST-1e with varying carbon dioxide CO2 and methane CH4 gas concentrations, and their corresponding prescribed spherical haze profiles. Our results show that the presence of CO2 leads to a warmer atmosphere globally due to its greenhouse effect, with the increase of surface temperature on the dayside surface reaching up to ∼14.1 K, and on the nightside up to ∼21.2 K. Increasing presence of CH4 first elevates the surface temperature on the dayside, followed by a decrease due to the balance of tropospheric warming and stratospheric cooling. A thin layer of haze, formed when the partial pressures of CH4 to CO2 (pCH4/pCO2) = 0.1, leads to a dayside warming of ∼4.9 K due to a change in the water vapour H2O distribution. The presence of a haze layer that formed beyond the ratio of 0.1 leads to dayside cooling. The haze reaches an optical threshold thickness when pCH4/pCO2 ∼ 0.4 beyond which the dayside mean surface temperature does not vary much. The planet is more favourable to maintaining liquid water on the surface (mean surface temperature above 273.15 K) when pCO2 is high, pCH4 is low, and the haze layer is thin. The effect of CO2, CH4, and haze on the dayside is similar to that for a rapidly rotating planet. On the contrary, their effect on the nightside depends on the wind structure and the wind speed in the simulation.

Impact of air entrapment on capillary absorption in porous building materials

When the water content of a porous material is high, air entrapped in the pore space is expected to affect water transfer through the pores. To understand the effects of air entrapment on water transfer in porous building materials in the high-water-saturation region, we examined the water transfer characteristics corresponding to significantly small air entrapment effects. First, we conducted two sets of water uptake experiments. In the first experiment, using three building materials, the time evolution of the amount of water absorption was measured at a low air pressure near vacuum (several kPa). In the second experiment, the water content profile during water uptake was measured using the gamma-ray attenuation method. The experimental results showed that low air pressure accelerated the water uptake by the brick and aerated concrete specimens, whereas water uptake by the calcium silicate board specimens was not significantly affected. These differences among materials were analyzed from a pore structure viewpoint. Moreover, gamma-ray attenuation measurements confirmed that the obtained water content profile was qualitatively similar at atmospheric and low air pressures, although the low air pressure increased both the water content of the material after capillary absorption and the wetting front propagation rate. Finally, simultaneous water and air transfer calculations based on the air and liquid water balance in a material reproduced the measured water absorption rates well, confirming that air entrapment and pressure development in the pores can significantly reduce the rate of water uptake and water content after capillary absorption. The calculation results also indicated that the air pressure in a material did not significantly increase at early water uptake stages where local water content was not high, which supported the general assumption that treating the liquid-water transfer in porous building materials as a one-component flow is valid in most cases.

Measurement report: Hygroscopicity of size-selected aerosol particles in the heavily polluted urban atmosphere of Delhi: impacts of chloride aerosol

Abstract. Recent research has revealed the crucial role of wintertime, episodic high chloride (H-Cl) emissions in the Delhi region, which significantly impact aerosol hygroscopicity and aerosol-bound liquid water, thus contributing to the initiation of Delhi fog episodes. However, these findings have primarily relied on modeled aerosol hygroscopicity, necessitating validation through direct hygroscopicity measurements. This study presents the measurements of non-refractory bulk aerosol composition of PM1 from an Aerodyne aerosol chemical speciation monitor and for first-time size-resolved hygroscopic growth factors (nucleation, Aitken, and accumulated mode particles) along with their associated hygroscopicity parameters at 90 % relative humidity using a hygroscopic tandem differential mobility analyzer at the Delhi Aerosol Supersite. Our observations demonstrate that the hygroscopicity parameter for aerosol particles varies from 0.00 to 0.11 (with an average of 0.03 ± 0.02) for 20 nm particles, 0.05 to 0.22 (0.11 ± 0.03) for 50 nm particles, 0.05 to 0.30 (0.14 ± 0.04) for 100 nm particles, 0.05 to 0.41 (0.18 ± 0.06) for 150 nm particles, and 0.05 to 0.56 (0.22 ± 0.07) for 200 nm particles. Surprisingly, our findings demonstrate that the period with H-Cl emissions displays notably greater hygroscopicity (0.35 ± 0.06) in comparison to spans marked by high biomass burning (0.18 ± 0.04) and high hydrocarbon-like organic aerosol (0.17 ± 0.05) and relatively cleaner periods (0.27 ± 0.07). This research presents initial observational proof that ammonium chloride is the main factor behind aerosol hygroscopic growth and aerosol-bound liquid water content in Delhi. The finding emphasizes ammonium chloride's role in aerosol–water interaction and related haze/fog development. Moreover, the high chloride levels in aerosols seem to prevent the adverse impact of high organic aerosol concentrations on cloud condensation nuclei activity.

Correlated libration in liquid water.

The libration spectrum of liquid H2O is resolved into an octupolar twisting libration band at 485 cm-1 and dipolar rocking-wagging libration bands at 707 and 743 cm-1 using polarization analysis of the hyper-Raman scattering (HRS) spectrum. Dipole interactions and orientation correlation over distances less than 2nm account for the 36 cm-1 splitting of the longitudinal and transverse polarized bands of the dipolar rocking-wagging libration mode, while the intensity difference observed for the bands is the result of libration correlation over distances larger than 200nm. The coupled rock and wag libration in water is similar to libration modes in ice. The libration relaxation time determined from the width of the spectrum is 36-54fs. Polarization analysis of the HRS spectrum also shows long range correlation for molecular orientation and hindered translation, bending and stretching vibrations in water.

Study on gas accumulation in polymer electrolyte membrane water electrolyzer considering two-phase flow

In this study, we analyze gas accumulation in a polymer electrolyte membrane water electrolyzer by considering two-phase flows in the porous transport layer on the anode and cathode sides. First, effect of mass flow rate on gas accumulation is analyzed. The transport of liquid water occurred differently on the anode and cathode sides. While the transport of liquid water on the anode side decreased in the high current density region, that on the cathode side increased with current density. The limiting current density increased by 1.2 A/cm2 when the mass flow rate was increased. Next, we study the effect of contact angle of the porous transport layer. When the contact angle was decreased from 75° to 30°, gas saturation decreased by 0.04. The use of a hydrophilic porous layer on the cathode side, however, hindered the transport of liquid water into the channel because the porous transport layer tended to retain liquid water. Finally, we study the effect of porosity of the porous transport layer. When the porosity was 80%, the mass flow rate of liquid water into the porous layer was 0.1 g/s, and gas saturation was approximately 0.25 at 0.8 A/cm2.

Insights into the thermal insulation capability of a new polyurethane polymer subgrade material: An in-situ field test on the Qinghai–Tibet highway

The frost heave and thaw settlement of subgrades in permafrost regions severely threaten highway safety during repeated freeze–thaw cycles. However, these freeze–thaw cycles are difficult to overcome because of the lack of thermal insulation materials (or structures). To fill this gap, we developed a polyurethane (PU) polymer material with low thermal conductivity and designed a double–layer PU–grouted structure. The water–vapor–thermal coupling governing equations of the grouted subgrade were established. A numerical simulation was conducted using the finite element software COMSOL Multiphysics. Ten-month in-situ tests were conducted on the Qinghai–Tibet Highway from November 2021 to August 2022 to investigate the thermal insulation properties of the grouted subgrade. The results indicated that the PU exhibited excellent thermal insulation performance and considerably reduced the disturbance depth of the air temperature. Freeze and thaw depths were reduced by 0.65 and 1.65 m, respectively. During the freeze period, the surface and deep layers of the subgrade showed a temperature difference of 6 °C due to the upper PU layer, preventing 32.4 % of the liquid water from being frozen. The upper PU layer caused a temperature difference of up to 7 °C between the surface and the deep layers of the subgrade during the thawing period. Water evaporation was prevented by the upper PU layer, and water gathered between the grouted layers, which was defined as the “pot-cover effect.” The pot cover effect significantly reduced the soil temperature and maintained a stable temperature in the deeper subgrade during thawing.

Turbulence as a Key Driver of Ice Aggregation and Riming in Arctic Low‐Level Mixed‐Phase Clouds, Revealed by Long‐Term Cloud Radar Observations

AbstractTurbulence in clouds is known to enhance particle collision rates, as widely demonstrated for warm rain formation. A similar impact on ice growth processes is expected but a solid observational basis is missing. A statistical analysis of a 15‐month data set of cloud radar observations allows for the first time to quantify the impact of turbulence on ice aggregation and riming in Arctic low‐level mixed‐phase clouds. Increasing eddy dissipation rate (EDR), from below 10−4 to above 10−3 m2 s−3, yields larger ice aggregates, and higher particle concentration, likely caused by increasing fragmentation. In conditions more favorable to riming, higher EDR is associated with dramatically higher particle fall velocities (by up to 125%), under similar liquid water paths, indicative of markedly higher degrees of riming. Our findings thus reveal the key role of turbulence for cold precipitation formation, and highlight the need for an improved understanding of turbulence‐hydrometeor interactions in cold clouds.

Production Process of Premium Processed Fish in the Form of Tofu (Fish Tofu) at PT. Indo Lautan Makmur Sidoarjo Regency, East Java

This Field Work Practice (PKL) aims to find out the production process, especially processed fish tofu at PT. Indo Lautan Makmur. PKL was carried out on September 1, 2023 to September 30, 2023 at PT. Indo Lautan Makmur Sidoarjo Regency, East Java. The methods used in this field work practice are observation, interviews, field practice, dan literature study. PT. Indo Lautan Makmur is a food company that produces processed products from sea fish. The production process of processed fish tofu uses the main raw material surimi mixed with other supporting ingredients such as liquid ISP, tapioca folur, palm oil, ice water, flavouring, sugar, pepper, salt, white butter, and STTP. The sequence of production of processed fish tofu starts with the preparation of surimi, followed by the process of kneading, molding, boiling I, boiling II, cooling I, cutting, frying, cooling II, freezing, packaging, and then storing. The practical results show that process of processed fish tofu is in accordance with Good Manufacturing Practice (GMP) standards

Above-cloud concentrations of cloud condensation nuclei help to sustain some Arctic low-level clouds

Abstract. Previous studies have found that low-level Arctic clouds often persist for long periods even in the face of very low surface cloud condensation nuclei (CCN) concentrations. Here, we investigate whether these conditions could occur due to continuous entrainment of aerosol particles from the free troposphere (FT). We use an idealized large eddy simulation (LES) modeling framework, where aerosol concentrations are low in the boundary layer (BL) but increased up to 50× in the free troposphere. We find that the tests with higher tropospheric aerosol concentrations simulated clouds, which persisted for longer and maintained higher liquid water paths (LWPs). This is due to direct entrainment of the tropospheric aerosol into the cloud layer, which results in a precipitation suppression from the increase in cloud droplet number and in stronger cloud-top radiative cooling, which causes stronger circulations maintaining the cloud in the absence of surface forcing. Together, these two responses result in a more well-mixed boundary layer with a top that remains in contact with the tropospheric aerosol reservoir and can maintain entrainment of those aerosol particles. The surface aerosol concentrations, however, remained low in all simulations. The free-tropospheric aerosol concentration necessary to maintain the clouds is consistent with concentrations that are frequently seen in observations.

Thermophysical insights and COSMO-RS study of triethylenetetramine-based protic ionic liquids with alkyl carboxylic acids

Protic ionic liquids (PILs) have increasing interest due to their potential application compared to conventional organic solvents. In the present study, new class of protic ionic liquids were developed by combining triethylenetetramine as cation and distinct carboxylic acids, specifically formic acid, butanoic acid, hexanoic acid, and octanoic acid employed as the anions. The products structures and purity were verified using 1H and 13C NMR as well as ESI-MS analysis. The structural variations effects on the thermophysical characteristics such as refractive index (nD), viscosity (η), density (ρ), and speed of sound (u) were evaluated throughout a broad temperature range. Temperatures between 293.15 and 333.15 K were used to calculate the viscosity and density values. It was also determined the thermal decomposition temperature (Td) and quantified the amount of water in the synthetic protic ionic liquids. Additional parameters such the expansion coefficient (α), standard entropy (S0), volume (V), lattice potential energy (UPOT), isentropic compressibility (βs), Intermolecular free length (Lf) of PILs were calculated using experimental values for sound speed and density. Furthermore, computation of activation energy employed the experimental viscosity values. In order to calculate the electronic polarizability and free volume present inside the ionic liquids, refractive indices of PILs were measured between the temperatures of 293.15 and 323.15 K. The study also explored the Conductor-like Screening Model for Real Solvents (COSMO-RS) computational approach to gain insights into the structural variation of TETA-based ionic liquids. The prepared PILs derived properties and linked with their structural moieties.

Differential Analysis of Various Moisture Phases on N2 Displacement of CH4 in Coal.

The aim of the study was to elucidate the impact of different moisture phases during gas injection on coalbed methane displacement. The coal samples were treated with two methods: water vapor adsorption and liquid water stirring. The differences in the coal samples treated with various moisture phases during gas injection for coalbed methane displacement were investigated by using the isothermal adsorption curves of CH4, N2, and H2O in coal and N2 displacement of CH4 in coal. The results indicate that variations in the gas adsorption capacity of coal are treated with different moisture phases. The gas adsorption capacities and displacement capacities of the coal samples treated with the water vapor adsorption methods are better than those treated with the stirring methods. In the isothermal adsorption experiment, for the coal samples treated with different moisture phases, at a moisture content of 2.75%, the saturated adsorption capacities of CH4/N2 are 0.204/0.189 (cm3/g), and at a moisture content of 5.63%, the saturated adsorption capacities of CH4/N2 are 0.151/0.139 (cm3/g). In addition, in the displacement experiment, for the coal samples treated with different moisture phases, at a moisture content of 2.75%, the difference in the total gas adsorption capacities is 0.62 cm3/g and the difference in the CH4 adsorption capacities is 0.473 cm3/g, and at a moisture content of 5.63%, the difference in the total gas adsorption capacities is 0.3 cm3/g and the difference in CH4 adsorption capacities is 0.22 cm3/g. For the coal samples treated with various moisture phases, the differences in the CH4/N2 adsorption and displacement capacities are greater at a moisture content of 2.75% than at 5.63%. Notably, the moisture phase has only a marginal influence on the CH4 desorption capacity and desorption rate. The study is important to understand the interactions between coal and moisture.

Can Recurrence Quantification Analysis Be Useful in the Interpretation of Airborne Turbulence Measurements?

AbstractIn airborne data or model outputs, clouds are often defined using information about Liquid Water Content (LWC). Unfortunately LWC is not enough to retrieve information about the dynamical boundary of the cloud, that is, volume of turbulent air around the cloud. In this work, we propose an algorithmic approach to this problem based on a method used in time series analysis of dynamical systems, namely Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA). We construct RPs using time series of turbulence kinetic energy, vertical velocity and temperature fluctuations as variables important for cloud dynamics. Then, by studying time series of laminarity (LAM), a variable which is calculated using RPs, we distinguish between turbulent and non‐turbulent segments along a horizontal flight leg. By selecting a single threshold of this quantity, we are able to reduce the number of subjective variables and their thresholds used in the definition of the dynamical cloud boundary.