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Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux 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.)

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux 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.)

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux 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.)

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux 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.)

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux 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.)

This work deals with the experimental analysis and the mathematical modelling of the CO 2 absorption in an initially quiescent aqueous solution of NaHCO 3 and Na 2 CO 3 inside a Hele-Shaw cell. This absorption, initially driven by the coupling between diffusion and chemical reactions, eventually leads to the apparition of a peculiar gravitational instability with non-monotonic dynamics, and liquid plumes generated at some distance from the gas-liquid interface (Wylock et al., 2014). Considering that this instability is triggered by a Rayleigh–Taylor like mechanism, a two-dimensional model, coupling diffusion, chemical reaction and convection, is proposed to simulate the onset and the dynamics of such an instability. It is observed that the simulated instability dynamics agree qualitatively with the experimental observations and that the order of magnitude of the onset time is well estimated. Thanks to the simulation, the interaction between the various phenomena after the instability onset is further investigated and a mechanism is proposed to explain the unusual dynamics of the studied system. It is notably shown that this dynamics is due to the particular non-monotonic liquid density variations with the depth, induced by the absorption. A criterion to obtain such type of density profile is presented. In addition, the simulation enables to assess the influence of the instability on the CO 2 absorption rate and it is observed that the generated flow pattern does not lead to a significant enhancement of the gas–liquid absorption rate. This result is of significant importance for optimizing chemisorption (e.g. for CO 2 capture or sequestration) processes. [ABSTRACT FROM AUTHOR]

The article discusses archaeological finds at a 1st century BCE trading center in Palmyra, Syria.

Graphical abstract Abstract Hypothesis The architecture of complex-shaped fibres affects the motion of the contact line and the evolution of its associated menisci when a fibre is immersed into a liquid. Understanding and predicting the motion of the contact line is critical in the design of complex-shaped fibres for many engineering applications as well as for surface science. While wetting on classic circular cylinders has been well studied, singularities during the wetting process of complex-shaped fibres are not yet well understood. Experiments The dynamic wetting behaviour of axisymmetric sinus-shaped fibres immersed vertically in a liquid volume was investigated. Fibres were 3D-printed down to micrometre dimensions, and the Wilhelmy method was used in parallel with meniscus shape analysis. Moreover, a quasi-static theoretical model predicting the contact line movement and free energy of the system evolution on these fibres is also proposed. Findings The observation of liquid advancing and receding fronts highlighted a stick-slip motion of the meniscus depending on both the fibre surface curvature and its intrinsic wettability. The model predicts that the behaviour of the seemingly pinned and then jumping contact line, with associated changes in apparent contact angles, can be explained by the interplay between a constant local contact angle and the movement of the bulk liquid, leading to the storage of energy which is suddenly released when the contact line passes a given point of fibre curvature. Besides, acceleration/deceleration events that take place before and after the jumps are experimentally observed in good agreement with the model. [ABSTRACT FROM AUTHOR]

This work is centered upon the thermal transients taking place during the evaporation of a spherical drop of a pure liquid suspended in a gaseous environment. Based on mass and energy conservation equations, a so-called complete model is developed considering quasi-steady diffusive and Stefan convective transports in the non-isothermal gas phase, and unsteady conduction in the liquid drop. A simplified version of the complete model, the so-called quasi-homogeneous model, is developed using an asymptotic analysis in the limit of small thermal homogenization time in the drop compared to the total drop evaporation time. The models enable highlighting the role of two dimensionless numbers, R and H , characterizing the two thermal transients of the problem: the thermal relaxation transient of the drop interfacial temperature and the thermal homogenization transient of the drop. The values of these two dimensionless numbers are provided for several liquids and their dependence on the evaporation conditions is discussed. It is shown that, when an accurate evaluation of the drop evaporation time is required by the considered application, the use of a fully quasi-steady model should be restricted to systems presenting small values of R compared to one (at least an order of magnitude smaller) and H < 1 . For other systems, it appears necessary to use the complete model or the quasi-homogeneous model. A simple formula is proposed to evaluate the relative difference between the drop evaporation times predicted by the complete model and by the fully quasi-steady model. When an accurate evaluation of the time evolution of the drop temperature field is required by the considered application, it appears to be necessary to use the complete model, whatever the system considered in this work. Indeed, the thermal transients can generally take an important part of the drop evaporation time and large temperature gradients can develop in the drop. The use of the complete model reveals that three different types of dynamics can be observed when a drop evaporates, depending on the relative values of three temperatures: the initial drop temperature, the dew point temperature of the gas far from the drop and the established interfacial temperature ( i.e. the drop interfacial temperature calculated using a fully quasi-steady model). [ABSTRACT FROM AUTHOR]

In this paper, a new comprehensive analysis of a suspended drop of a pure liquid evaporating into air is presented. Based on mass and energy conservation equations, a quasi-steady model is developed including diffusive and convective transports, and considering the non-isothermia of the gas phase. The main original feature of this simple analytical model lies in the consideration of the local dependence of the physico-chemical properties of the gas on the gas temperature, which has a significant influence on the evaporation process at high temperatures. The influence of the atmospheric conditions on the interfacial evaporation flux, molar fraction and temperature is investigated. Simplified versions of the model are developed to highlight the key mechanisms governing the evaporation process. For the conditions considered in this work, the convective transport appears to be opposed to the evaporation process leading to a decrease of the evaporation flux. However, this effect is relatively limited, the Péclet numbers happening to be small. In addition, the gas isothermia assumption never appears to be valid here, even at room temperature, due to the large temperature gradient that develops in the gas phase. These two conclusions are explained by the fact that heat transfer from the gas to the liquid appears to be the step limiting the evaporation process. Regardless of the complexity of the developed model, yet excluding extremely small droplets, the square of the drop radius decreases linearly over time ( R 2 law). The assumptions of the model are rigorously discussed and general criteria are established, independently of the liquid–gas couple considered. [ABSTRACT FROM AUTHOR]

Abstract: This work deals with the experimental characterization of carbon dioxide ( ) absorption in an aqueous solution of N-(2-hydroxyethyl)piperazine, by using of digital holographic interferometry. This method enables visualizing the phenomena taking place in the vicinity of the gas–liquid interface. Thanks to a calibration, the obtained results yield the time evolution of the loading field in the aqueous solution and the gas–liquid absorption rate for various operating conditions. The processing method and the obtained results are detailed. A phenomenological model, highlighting the limiting steps of the gas–liquid absorption, is proposed. A set of experiments is realized and the parameters of this model are estimated for various initial amine concentrations and initial loadings. The results are discussed and correlations are proposed for the model parameters. [Copyright &y& Elsevier]

The interplay between evaporation and liquid–liquid phase separation (demixing) in binary sessile drops of partially miscible liquids is investigated. To determine the onset of the demixing phenomenon, a simple model is developed, which predicts a considerable temperature reduction (∼20 °C) in the mixture due to evaporative cooling. Temperature reduction alongside with the change of composition lead to demixing in the mixtures. The model explains why a mixture at room temperature is able to demix, whilst the demixing upper critical temperature is at 6.3 °C. Five stages of the process are identified and explained. For the cases studied here, once the demixing begins through nucleation, a growing fingering pattern is formed at the contact line. The length of the fingers and the final area of deposition increase with the initial concentration. Experimental tests were performed using a double telecentric setup. [ABSTRACT FROM AUTHOR]

This paper reports the improvement in the efficiency of embedded-cluster model (ECM) calculations in ORCA thanks to the implementation of the fast multipole method. Our implementation is based on state-of-the-art algorithms and revisits certain aspects, such as efficiently and accurately handling the extent of atomic orbital shell pairs. This enables us to decompose near-field and far-field terms in what we believe is a simple and effective manner. The main result of this work is an acceleration of the evaluation of electrostatic potential integrals by at least one order of magnitude, and up to two orders of magnitude, while maintaining excellent accuracy (always better than the chemical accuracy of 1 kcal/mol). Moreover, the implementation is versatile enough to be used with molecular systems through QM/MM approaches. The code has been fully parallelized and is available in ORCA 6.0., (© 2024 The Author(s). Journal of Computational Chemistry published by Wiley Periodicals LLC.)

In this work, we investigate the spectroscopic properties of photochromic alexandrite and cordierite by TD-DFT. The objective is to assess the TD-DFT for the simulation of pleochroism (change of color depending on the crystallographic direction of the observation) and the change of color as a function of the light source. For these simulations, we compared an embedding where dangling bonds are saturated by hydrogen atoms and an electrostatic embedding. The electrostatic embedding provided numerically more stable results and allowed a good reproduction of the pleochroism of cordierite, based on a Fe 2+ -Fe 3+ intervalence charge transfer transition. However, the pleochroism of alexandrite is not as well reproduced, suggesting that TD-DFT has some difficulties to reproduce the anisotropy of the transition dipole moment, an aspect that is not deeply documented in the literature., (© 2023 The Authors. Journal of Computational Chemistry published by Wiley Periodicals LLC.)

SignificanceNatural photochromic minerals have been reported by geologists for decades. However, the understanding of the photochromism mechanism has a key question still unanswered: What in their structure gives rise to the photochromism's reversibility? By combining experimental and computational methods specifically developed to investigate this photochromism, this work provides the answer to this fundamental question. The specific crystal structure of these minerals allows an unusual motion of the sodium atoms stabilizing the electronic states associated to the colored forms. With a complete understanding of the photochromism mechanism in hand, it is now possible to design new families of stable and tunable photochromic inorganic materials-based devices.

The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of the specification, v1.0, which is already supported by many leading databases and several software packages. We illustrate the advantages of the OPTIMADE API through worked examples on each of the public materials databases that support the full API specification., (© 2021. The Author(s).)

Hypothesis: Volatile binary liquid samples on wetting substrates are known to undergo either spreading or contraction tendencies, as a result of solutal Marangoni stresses due to differential volatility. Enhanced spreading is commonly thought to occur when the lower surface tension component is more 'volatile', while contraction is expected otherwise. We seek to test the limits of this scenario for various configurations such as sessile drops with free or pinned contact lines, without or with microparticles, and tears-of-wine menisci., Experiments: We consider isopropanol- and ethanol-water mixtures, important in numerous applications. We conduct interferometric experiments with sessile droplets for multiple combinations of the initial concentration and controlled ambient humidity (water vapour only), essentially covering the entire range of these parameters. Experiments are also carried out for other configurations mentioned above., Findings: Contraction regimes are found in certain situations where spreading is expected, despite the alcohols being more volatile than water. Furthermore, regime reversals occur between cases with different initial liquid concentrations even at zero humidity, and are not necessarily associated with the existence of an azeotropic composition. Such surprising observations are rationalized by a simple model highlighting the often overlooked role of the diffusion coefficient ratio of the two vapours in conjunction with the non-ideality of the mixture. Our picture of the phenomenon is demonstrated to be universal for all configurations studied., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

We uncover the existence of several competitive mechanisms of water oxidation on the β-CoOOH (10-14) surface by going beyond the classical 4-step mechanism frequently used to study this reaction at the DFT level. Our results demonstrate the importance of two-site reactivity and of purely chemical steps with the associated activation energies. Taking the electrochemical potential explicitly into account leads to modifications of the reaction energy profiles finally leading to the proposition of a new family of mechanisms involving tetraoxidane intermediates. The two-site mechanisms revealed in this work are of key importance to rationalize and predict the impact of dopants in the design of future catalysts.

When a liquid droplet is placed on a very hot solid, it levitates on its own vapor layer, a phenomenon called the Leidenfrost effect. Although the mechanisms governing the droplet's levitation have been explored, not much is known about the fate of the Leidenfrost droplet. Here we report on the final stages of evaporation of Leidenfrost droplets. While initially small droplets tend to take off, unexpectedly, the initially large ones explode with a crack sound. We interpret these in the context of unavoidable droplet contaminants, which accumulate at the droplet-air interface, resulting in reduced evaporation rate, and contact with the substrate. We validate this hypothesis by introducing controlled amounts of microparticles and reveal a universal 1/3-scaling law for the dimensionless explosion radius versus contaminant fraction. Our findings open up new opportunities for controlling the duration and rate of Leidenfrost heat transfer and propulsion by tuning the droplet's size and contamination.

The drying of colloidal suspensions is a very complex process leading to a sol-gel transition induced by solvent evaporation. The resulting film can even crack and delaminate. In this study, we investigate the drying process of a colloidal suspension with a highly volatile solvent and we show for initially millimeter-thick layers that the resulting pattern of delaminated plates considerably differs from what is usually observed for aqueous colloidal suspensions. Visualization using an IR camera reveals that hexagonal convection cells can develop during the drying of suspensions with a highly volatile solvent and may persist until the film consolidation. This leads to the formation of non-homogeneous films presenting surface corrugations. Thus, we highlight the importance of the hydrodynamics during the first phase of strong solvent evaporation and its consequences for the following drying steps. A criterion predicting whether or not Bénard-Marangoni instability effectively occurs will be discussed. Finally, we report a non-classical delamination mode generating fragments with convex surfaces, whereas buckle-driven delamination usually results in concave shapes.

Mach-Zehnder interferometry was applied to explore the effects of inhomogeneous magnetic fields on the mobility of rare-earth ions in aqueous solutions. No migration of ions was observed in a thermodynamically closed system when a homogeneous solution was subjected to a magnetic field gradient alone. However, magnetomigration could be triggered by a concentration gradient of the rare-earth ions in the solution. When a concentration gradient was introduced in the sample by solvent evaporation, consistent migration of paramagnetic Dy 3+ ions from the bulk solution to regions with stronger magnetic fields was observed. By contrast, no movement was detected for diamagnetic Y 3+ ions in the presence of a concentration gradient.

It is known that the addition of an insoluble surfactant to a Bénard-Marangoni (BM) layer heated from below or cooled from above can give rise to a supplementary, oscillatory mode of instability. Here the objective is to see how exactly this plays out in the framework of a recently studied and experimentally tested case of a non-long-wavelength BM instability driven by diffusion-limited evaporation into air in isothermal surroundings. Linear stability analysis is accomplished within a now standard reduction to a one-sided model. In the absence of surfactant, we just recover the classical Pearson problem, albeit with an evaporation-specific wavenumber-dependent Biot number potentially attaining large values for strongly volatile liquids. Adding a surfactant not only sharply stabilizes the monotonic Pearson-like mode, but also leads to a more dangerous oscillatory mode, a parametric study of which is here undertaken. Although slanted towards the evaporative case, the present study is also of interest from the general viewpoint of the Pearson problem + an insoluble surfactant, the results for which are scarce in the literature without being obscured by further effects. In particular, an asymptotic analysis based on small interfacial Lewis numbers (diffusion coefficients) is undertaken near the codimension-2 point.

During the spreading of a liquid over a solid substrate, the contact line can stay pinned at sharp edges until the contact angle exceeds a critical value. At (or sufficiently near) equilibrium, this is known as Gibbs' criterion. Here, we show both experimentally and theoretically that, for completely wetting volatile liquids, there also exists a dynamically-produced contribution to the critical angle for depinning, which increases with the evaporation rate. This suggests that one may introduce a simple modification of the Gibbs' criterion for (de)pinning that accounts for the nonequilibrium effect of evaporation.

We investigated the organization of micrometric hydrophilic beads (glass or basalt) immersed in Leidenfrost drops. Starting from a large volume of water compared to the volume of the beads, while the liquid evaporates, we observed that the grains are eventually trapped at the interface of the droplet and accumulate. At a moment, the grains entirely cover the droplet. We measured the surface area at this moment as a function of the total mass of particles inserted in the droplet. We concluded that the grains form a monolayer around the droplet assuming (i) that the packing of the beads at the surface is a random close packing and (ii) that the initial surface of the drop is larger than the maximum surface that the beads can cover. Regarding the evaporation dynamics, the beads are found to reduce the evaporation rate of the drop. The slowdown of the evaporation is interpreted as being the consequence of the dewetting of the particles located at the droplet interface which makes the effective surface of evaporation smaller. As a matter of fact, contact angles of the beads with the water deduced from the evaporation rates are consistent with contact angles of beads directly measured at a flat air-water interface of water in a container.

The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory.

For a liquid advancing or receding on a flat bare solid in a vapor atmosphere, we show that no singularities in fact arise at the contact (triple) line. Contrary to common expectations, this does not require any "regularizing" microscopic effect (such as slip at the substrate, disjoining pressure or precursor films). The key here is the Kelvin effect, i.e., a curvature-induced variation of saturation conditions. Importantly, no evaporation-related singularities appear either. We proceed within the lubrication approximation and a classical one-sided model for zero or finite contact angle.

The microstructure of a contact line formed by a liquid and its pure vapor on a perfectly wetted superheated smooth substrate, with the disjoining pressure most often in the form of a positive inverse cubic law (nonpolar case), is routinely considered to end up in a microfilm extended over adjacent "dry" parts of the solid surface. Invoking the spreading coefficient as an additional independent parameter within this framework, we argue however that a regime with a truncated microfilm is chosen instead if the spreading coefficient is decreased below a positive (still perfect wetting) critical value dependent upon the superheat, in which case the extended-microfilm thickness is surpassed by that of the "pancake" introduced by de Gennes and co-workers. Conversely, for a given positive spreading coefficient, there is a critical superheat above which the microfilm gets truncated, whereas for a negative one (partial wetting) the truncated regime should be preferred at any superheat. A parametric study of the apparent contact angle (a nonlinear eigenvalue of the steady microstructure problem) versus the spreading coefficient is carried out. When the latter is negative, Young's law is asymptotically recovered. Microfilm fronts on a bare surface are shown to be advancing or receding in accordance with the selected regime. A slightly more general class of disjoining pressures is also touched upon. The analysis is based in part upon thermodynamic considerations and in part upon a standard one-sided model of an evaporating liquid layer in the lubrication approximation.

We study three-dimensional wave patterns on the surface of a film flowing down a uniformly heated wall. Our starting point is a model of four evolution equations for the film thickness h , the interfacial temperature theta , and the streamwise and spanwise flow rates, q and p , respectively, obtained by combining a gradient expansion with a weighted residual projection. This model is shown to be robust and accurate in describing the competition between hydrodynamic waves and thermocapillary Marangoni effects for a wide range of parameters. For small Reynolds numbers, i.e., in the "drag-gravity regime," we observe regularly spaced rivulets aligned with the flow and preventing the development of hydrodynamic waves. The wavelength of the developed rivulet structures is found to closely match the one of the most amplified mode predicted by linear theory. For larger Reynolds numbers, i.e., in the "drag-inertia regime," the situation is similar to the isothermal case and no rivulets are observed. Between these two regimes we observe a complex behavior for the hydrodynamic and thermocapillary modes with the presence of rivulets channeling quasi-two-dimensional waves of larger amplitude and phase speed than those observed in isothermal conditions, leading possibly to solitarylike waves. Two subregions are identified depending on the topology of the rivulet structures that can be either "ridgelike" or "groovelike." A regime map is further proposed that highlights the influence of the Reynolds and the Marangoni numbers on the rivulet structures. Interestingly, this map is found to be related to the variations of amplitude and speed of the two-dimensional solitary-wave solutions of the model. Finally, the heat transfer enhancement due to the increase of interfacial area in the presence of rivulet structures is shown to be significant.

The influence of the horizontal component of the temperature gradient on nonlinear regimes of oscillatory Marangoni convection in a real symmetric three-layer system is investigated. The transitions between different flow regimes have been studied. The general diagram of regimes is constructed.

A theoretical model of the evaporation of a pure liquid layer is developed. We focus on the influence of an inert gaseous component, in addition to vapor, on surface-tension-driven Bénard instabilities. It is assumed that the gas phase is perfectly mixed at some distance from the liquid-gas interface (given composition, pressure, and temperature). If this distance is not much larger than the liquid layer thickness, it is shown that a reduction of the full two-layer problem to a one-layer problem is possible, provided the evaporation rate is not too large. An analytical expression is given for the corresponding dimensionless heat transfer coefficient (a generalized, wavenumber-dependent Biot number) at the evaporating interface. The approach is validated through a comparison with a direct numerical resolution of the full two-layer problem.