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This paper presents an improved theoretical view of ab initio thermodynamics for polar GaN surfaces under gallium-rich conditions. The study uses density functional theory (DFT) calculations to systematically investigate the adsorption of gallium atoms on GaN polar surfaces, starting from the clean surface and progressing to the metallic multilayer. First principles phonon calculations are performed to determine vibrational free energies. Changes in the chemical potential of gallium adatoms are determined as a function of temperature and surface coverage. Three distinct ranges of Ga coverage with very low, medium, and high chemical potential are observed on the GaN(000-1) surface, while only two ranges with medium and high chemical potential are observed on the GaN(000-1) surface. The analysis confirms that a monolayer of Ga adatoms on the GaN(000-1) surface is highly stable over a wide range of temperatures. For a second adlayer at higher temperatures, it is energetically more favorable to form liquid droplets than a uniform crystalline adlayer. The second Ga layer on the GaN(0001) surface shows pseudo-crystalline properties even at a relatively high temperature. These results provide a better thermodynamic description of the surface state under conditions typical for molecular beam epitaxy and offer an interpretation of the observed growth window. [ABSTRACT FROM AUTHOR]

The study concerns the evaluation of the physicochemical and thermo-adsorptive surface properties of six commercially available mouthrinses, particularly surface tension, surface activity, partitioning coefficient, critical micellar concentration, Gibbs excesses at interfaces, surface entropy, and enthalpy. The aim was to quantify their effect on the adhesion and wettability of a model poly(methyl methacrylate) (PMMA) polymer. The adsorptive and thermal surface characteristics were derived from surface tension (γLV) vs. concentration and temperature dependences. Polymer surface wettability was characterized by the contact angle hysteresis (CAH) formalism, using the measurable advancing ΘA and receding ΘR dynamic contact angles and γLV as the input data. Further, wettability parameters: Young static angle (Θ), film pressure (Π), surface free energy (γSV) with its dispersive and polar components, work of adhesion (WA), and adhesional tension (γLV cosΘA) were considered as interfacial interaction indicators. The mouthrinse effect demonstrated the parameter's evolution in reference to the PMMA/pure water case: Θ, ΘA and ΘR↓, CAH↑, Π↓, WA↓, γSV↓, and γLVcosΘA↑. Furthermore, the variations of the surface excess ratio pointed to the formation of multilayered structures of surfactants composing the mouthrinse mixtures considered. The contact angle data allowed for the penetration coefficient and the Marangoni temperature gradient-driven liquid flow speed to be estimated. [ABSTRACT FROM AUTHOR]

Analytic profiles for periodic grain boundary grooves (PGBGs) were determined from variational theory. Variational profiles represent stationary solid-liquid profiles with abrupt, zero-thickness, transitions between adjoining phases. Variational PGBGs consequently lack tangential interfacial fluxes, the existence of which requires more realistic (non-zero) interfacial thicknesses that allow energy and solute transport. Variational profiles, however, permit field-theoretic calculations of their scaled formation free energy and thermodynamic stability, capillary-mediated chemical potentials, and their associated vector gradient distributions, all of which depend on a profile's geometry, not its thickness. Despite the fact that variational profiles are denied interface fluxes, one may, nevertheless, impute shape-dependent interface transport in the form of a profile's surface Laplacian of its presumptive chemical potential distribution due to capillarity. We compare variational surface Laplacians with residuals of the thermochemical potential measured along counterpart diffuse-interface PGBGs, simulated via phase-field with metrically-proportional profiles. Fundamentally, it is the thickness of a microstructure's interfaces and its shape that co-determine whether, and to what extent, gradients of the chemical potential excite fluxes that transport energy and/or solute. PGBGs, both variational and simulated, greatly expand the limited universe of solid-liquid microstructures suitable for steady-state thermodynamic analysis. Understanding the origin and action of these capillary-mediated interfacial fields opens a pathway for estimating and, eventually, measuring how solid-liquid interface thickness modifies the transport of energy and solute during solidification and crystal growth, and influences microstructure. [ABSTRACT FROM AUTHOR]

Traditional batch crystallization processes encounter challenges like batch-to-batch variability, and difficulty in scale-up and achieving desired crystal size and morphology. These challenges stem from various growth mechanisms within crystallizers, influenced by operating conditions that dictate the dynamic surface structure of crystals. To overcome this, we developed a novel microscopic kinetic Monte Carlo model, which uses a specialized adsorption rate that adapts to different growth regimes by considering surface thermodynamic effects for different growth mechanisms. Specifically, the adaptive adsorption rate redefines the driving force of crystallization by considering the attachment energies of different adsorption sites (e.g., kink, adatom, and edge) and supersaturation. This approach enables seamless transitions across growth regimes. We use the lysozyme crystal system as a case study, demonstrating the model's superior predictive power in regime-to-regime transitions. Overall, the developed work provides a valuable new approach to understanding crystal morphology and predicting crystal growth rates in different growth regimes. • A new kMC model for protein crystal growth is developed. • Different adsorption sites facilitate transitions between growth regimes. • Attachment energies correlate growth mechanisms to supersaturation. • Experimental data for Lysozyme crystals validates the kMC model. [ABSTRACT FROM AUTHOR]

Dry methane reforming (DRM) presents a promising strategy to convert greenhouse gases (CH 4 and CO 2) into syngas, a valuable precursor for the production of long-chain alkanes. However, catalyst deactivation remains a major issue, primarily caused by the deep cracking of CH 4 and CO 2 as well as the metal-catalyzed growth of carbon whiskers. To address this challenge, we introduce a multiscale model that analyzes DRM reactions on the N i surface and predicts whisker formation. The multiscale modeling approach integrates microscopic kinetic Monte Carlo (kMC) simulations for surface reactions, mesoscopic pellet-scale modeling for predicting whisker growth length and macroscopic modeling to consider packed bed porosity and pressure drop across the reactor. Further, by systematically introducing time-steppers using the gap-tooth scheme, we significantly improved the computational efficiency, reducing the computational time from 17 days to 6 h at the expense of minimal accuracy loss in predicting whisker length. Based on this, we assert that such a multiscale model enables the analysis of various operating conditions affecting catalyst deactivation and kinetics of surface reaction, aiding in the design and optimization of DRM process. • The multiscale model predicts catalyst deactivation in dry methane reforming (DRM). • The whisker growth predictions are validated under various experimental conditions. • kMC simulations were integrated with larger-scale models for DRM analysis. • The simulation time was reduced from 17 days to 6 h using a gap-tooth scheme. [ABSTRACT FROM AUTHOR]

It is argued that the criticism by Faraji et al. is unfounded and clarified further why surface stress on a strain-free solid, as postulated by Shuttleworth, does not exist. [ABSTRACT FROM AUTHOR]

[Display omitted] Pressure dependence of contact angle is expected to be influenced by temperature. Nevertheless, the correlation of water contact angle with pressure is rarely investigated at high temperatures (over 100 ℃). In this work, measurements of the contact angle and interfacial tension of water in N 2 atmosphere were conducted at various pressures and temperatures (up to 17 MPa and 300 ℃). The experimental observations were elucidated based on the theory of surface thermodynamics. It was shown that the water-N 2 interfacial tension linearly decreases with increasing the pressure, and that the pressure coefficient declines as temperature rises. The pressure dependence of the water contact angle was found to be different for the low- and high-temperature regimes: the water contact angle increases below 100 ℃, whereas an inverse variation occurs over 100 ℃. According to the theoretical analysis, the pressure dependence of both the water interfacial tension and contact angle is attributed to N 2 adsorption on the surfaces of water and silicon. The variations in the water contact angle with pressure, including both the sign and magnitude, are actually the consequence of the changes of water-N 2 and Si-N 2 interfacial tensions manipulated by pressure and temperature. [ABSTRACT FROM AUTHOR]

As a fluid approaches three phase coexistence, adsorption may take place by the successive formation of two intervening wetting films. The equilibrium thickness of these wetting layers is the result of a delicate balance of intermolecular forces, as dictated by an underlying interface potential. The van der Waals forces for the two variable adsorption layers may be formulated exactly from Dzyaloshinskii-Lifshitz-Pitaevskii theory, and analytical approximations may be derived that extent well beyond the validity of conventional Hamaker theory. We consider the adsorption equilibrium of water vapor on Silver Iodide where both ice and a water layers can form simultaneously and compete for the vapor as the triple point is approached. We perform numerical calculations of Lifshitz theory for this complex system and work out analytical approximations which provide quantitative agreement with the numerical results. At the three phase contact line between AgI/water/air, surface forces promote growth of ice both on the AgI/air and the water/vapor interfaces, lending support to a contact nucleation mode of AgI in the atmosphere. Our approach provides a framework for the description of adsorption at three phase coexistence, and allows for the study of ice nucleation efficiency on atmospheric aerosols. [ABSTRACT FROM AUTHOR]

[Display omitted] • Negative effects of filamentous bulking on granular anammox process was explored; • Evolution of anammox granular characteristics were systematically examined; • Determination of boundary layer thickness of granular sludge was developed; • Granular surface thermodynamic properties were analyzed based on XDLVO theory; • Shear stress-based operational strategy under filamentous bulking was proposed; In this study, the filamentous bulking (FB) with moderate and excessive levels were demonstrated to induce anammox failure by inhibiting nitrogen (N) removal and biomass retention. The low external mass transfer resulted from high liquid-surface friction and low turbulence of filamentous surface was considered the "trigger" of anammox failure, which decreased flux of nitrogen flow toward granular surface and directly limited N-removal loading, which meanwhile exposed granules with N-scarcity environment and indirectly inhibited N-removal bio-activity. Low bio-activity performed poor extracellular polymeric substances secretion further destroyed bio-aggregation with low suface hydrophobicity, which acted as "accelerator" for granule disintegration and biomass washout, ultimatly leading to anammox failure. Fortunately, incresing hydraulic shear stress could eradicate FB's negative effects without inhibiting FB itself, which promoted re-granulation and N-remval restore by enhancing external mass transfer more than hydraulic detachment. Enhancing mechanical stirring with FB level was necessary to maintain stable operation of granular anammox system. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Adhesion of A. manzaensis to chalcopyrite was investigated experimentally and theoretically. • Temperature and pH affect the adsorption behavior of A. manzaensis on chalcopyrite. • The extended DLVO theory was introduced to explain the archaeon adsorption process. • The adsorption behaviors of different energy sources adapted A. manzaensis were analyzed. Abstract The adsorption of Acidianus manzaensis YN25 on chalcopyrite was investigated experimentally and theoretically. A. manzaensis showed high adhesion affinity to the chalcopyrite under acidic condition, but low adhesion affinity under neutral and alkaline conditions. The microbe-mineral adhesion was assessed by the surface thermodynamics and the extended DLVO theory. The experimental results were in agreement with the theory. Moreover, A. manzaensis grown on chalcopyrite, sulfur, and ferrous ion showed similar adsorption phenomena. The adsorptive capacity of A. manzaensis increased with increasing temperature and decreasing pH respectively, and within the range of investigation, the best adsorption was achieved at pH 2.0 and 65 °C. This study provided new insights for bio-catalytic oxidation of sulfide minerals by the thermophilic acidophilic archaea. [ABSTRACT FROM AUTHOR]

Ductility-dip cracking (DDC) fracture surfaces containing thermal faceting (TF) are documented in this study. Research began with the discovery of TF on the DDC fracture surface in the weld metal of high-chromium nickel (Ni)-based filler metal 52M, a valuable alloy to the nuclear industry. Fracture surfaces were generated using strain-to-fracture (STF) and simulated strain ratcheting (SSR) testing on a Gleeble® thermomechanical simulator. Initial fractography performed by scanning electron microscopy (SEM) revealed faceting with preferred grain orientations and faceting interacting with void nucleation near grain boundary (GB) triple points. Internal voids were exposed via metallography, where TF was also observed on the free surface. A thin orientation- and site-specific foil was extracted from the faceted fracture surface using focused ion beam (FIB) nanofabrication. Subsequent scanning transmission electron microscopy (STEM) characterization down to atomic-resolution revealed the facets have perfect crystallographic orientations parallel to close-packed directions. Sharp edges and transitions between individual facets on the scale of individual atomic columns and atomic planes were observed. An analysis of the deformation microstructure and the chemical composition underneath the faceted surface showed a low dislocation density and no evidence of localized segregation or diffusion, respectively. These findings have led to the development of a hypothesis related to the interdependence of TF and DDC and support initial claims regarding TF formation in DDC voids at elevated temperatures. [ABSTRACT FROM AUTHOR]

The surface tensions (γ) of 2-diethylaminoethanol (DEAE)–tetramethylammonium glycinate ([N 1111 ][Gly]), DEAE–1-butyl-3-methylimidazolium glycinate ([Bmim][Gly]) and DEAE–1-butyl-3-methylimidazolium l -lysinate ([Bmim][Lys]) aqueous solutions were measured by using the BZY-1 surface tension meter. The temperature ranged from 303.2 K to 323.2 K. The mass fractions of DEAE and amino acid ionic liquids (AAILs) respectively ranged from 0.30 to 0.50 and 0.025 to 0.075. A thermodynamic equation was proposed to model the surface tension and the calculated results agreed well with the experiments. The effects of temperature and mass fractions of DEAE and AAILs on the surface tension were demonstrated on the basis of experiments and calculations. The surface enthalpy and surface entropy were determined and their concentration dependences were illustrated. [ABSTRACT FROM AUTHOR]

We report and provide justification for the consistently observed four experimental facts of mass spectrometric data of carbon cluster emission from the Cs+-irradiated single-walled carbon nanotubes (SWCNTs). Firstly, the diatomic carbon C2is the most abundant sputtered species. Secondly, monatomic carbon C1yield is Cs+energy dependent. Thirdly, at low caesium energies, only C2, C3and C4are emitted. Lastly, the normalised yield of C1monotonically increases while C2, C3and C4show gradual decrease leading to saturation. The experimental data for the normalised density of clusters and atoms follow the pattern >  >  > . A statistical thermal model is developed to explain the experimentally observed sputtering of clusters. The probability of a cluster Cxto be emitted is proportional to that for the creation of anx-member vacancy with formation energyExvat temperatureTsas {exp(Exv/kTS) + 1}−1. The energies of formation of vacancies from DFT calculations and the ratio of normalised experimental yields have been used to estimateTS. OnceTsis evaluated, the formation energies of tri- and quarto-vacancies are obtained using the ratios of normalised densitiesand. We show that by invoking thermal spikes, cluster emission from, and the multiple vacancy generation in, the Cs+-irradiated SWCNTs can be explained. [ABSTRACT FROM AUTHOR]

The diffusion behaviors of single Au, Ag and Cu atoms on Si(111)-(7 × 7) half unit cells have been investigated via combining scanning tunneling microscopy and first-principles calculations. Despite the similar adsorption sites between both half unit cells among these elements, the diffusion dynamics show obvious differences between Ag and the other two. Although obvious asymmetry has been found in the diffusion behaviors of Au and Cu atoms in two half unit cells of Si(111)-(7 × 7), the asymmetry behaves in a way different from that of Ag atoms and no dual-time character has been observed for the diffusions of Au and Cu in both half unit cells. Theoretical calculations suggest a different potential energy profile caused by the stronger hybridization between d states of Au (Cu) and Si states make the concept of basin useless for the diffusion of Au and Cu atoms inside the half unit cells of Si(111)-(7 × 7). [ABSTRACT FROM AUTHOR]

We have investigated the bulk and surface properties of the group II metal fluorides CaF2, SrF2 and BaF2 using periodic density functional theory (DFT) calculations and surface thermodynamics. Our bulk results show that the best agreement with experiment is achieved with the B3LYP and PBE functionals. We determined the relative importance of the low index surfaces in vacuum and found that an fluoride microcrystal exposes only the (111) surface in which the undercoordinated cations are sevenfold coordinated. With methods of ab initio surface thermodynamics, we analyzed the stability of different surfaces under hydrogen fluoride (HF) pressure and determined the presumable shape of the crystals with respect to different HF concentrations and temperatures. In the case of CaF2 and SrF2, the calculated shapes of the crystals agree well with TEM images of fluorolytic sol-gel synthesized nanocrystals at room temperature and high HF concentration. [ABSTRACT FROM AUTHOR]

The surface tension (γ) of 1-dimethylamino-2-propanol (DMA2P), DMA2P-monoethanolamine (MEA), and DMA2P-piperazine (PZ) aqueous solutions was measured by using the BZY-1 surface tension meter. The temperature ranged from 303.2 K to 323.2 K. The mass fractions of DMA2P, MEA and PZ respectively ranged from 0.30 to 0.50, 0.05 to 0.15 and 0.025 to 0.075. An equation was proposed to model the surface tension and the calculated results agreed well with the experiments. The surface thermodynamics including surface enthalpy and surface entropy were determined and their concentration dependence was analysed. [ABSTRACT FROM AUTHOR]

The effect of temperature on the surface tension is examined in liquid alloys that combine a positive or negative temperature coefficient with gravity limitation of the surface concentration in the surface-active metal constituent. This is a restriction that is likely to occur in alloys where the metal with lower surface tension is much denser than the other component. Since there is a surface tension increase due to diminished segregation, the resultant temperature coefficient will depend on the superposition of two independent effects. Working in the framework of Butler's thermodynamics for ideal surface phases, equations and methods of analysis are obtained to describe both effects. These developments are illustrated with alloys where the surface density is likely to attain the bulk density at certain compositions, namely the Al–Zn alloys that exhibits a negative temperature coefficient and the Sn–Bi, Ga–Bi, Ga-Pb and Cu–Pb alloys that present composition ranges with positive temperature coefficients. The specific concave down d γ /d T curves of liquid alloys are theoretically predicted. Furthermore, good estimates are obtained for systems with positive and negative temperature coefficients, except within a 50 K interval of phase transitions, or for systems showing large deviations from ideal behaviour. [Display omitted] • Surface density effect on surface tension temperature coefficients of liquid alloys. • Thermodynamic calculation of ideal temperature coefficients for liquid metal alloys. • Experimental vs. theoretically estimated surface tension temperature coefficients. [ABSTRACT FROM AUTHOR]

In the previous paper (Gutman, JOSSEC 18:3217-3237, 2014), we have shown that the main problem in capillarity and electrocapillarity of solid surfaces is the lack of clarity in determining the surface stress and basic equations. Now, we continue the survey of efforts to solve this problem and show origins of erroneous results, accenting some important items: comparative analysis of Gibbs and Guggenheim approaches in surface thermodynamics (a geometrical dividing surface and finite-thickness surface layer, respectively), transformation of fundamental equations on per-unit-area basis to obtain Gibbs adsorption equation for finite-thickness surface layer, different attempts to derive the thermodynamic definition of 'surface stress' in frames of Gibbs' theory (including Shuttleworth's approach), atomistic calculations of surface stress, surface stress in rational continuum mechanics, 'modifications' of Gibbs-Duhem relations made for solid interface, and Maxwell relations in capillarity and electrocapillarity of solid interface. It is shown that the erroneous Shuttleworth's approach is present in an explicit or implicit form in all efforts to introduce the surface stress in frames of Gibbsian theory (although Gibbs did not introduce surface stress). Therefore, 'modernizations' or 'generalizations' of the Gibbs-Duhem relation, the Gibbs adsorption equation, and the Lippmann equation to adopt them for a solid surface are unnatural and not necessary. Therefore, we recommend withdrawing the Shuttleworth equation and its consequences from circulation, including the IUPAC Recommendations. [ABSTRACT FROM AUTHOR]

A lattice gas model is used with Wang-Landau Monte Carlo sampling to predict the capillary force between a model of an atomic force microscopy (AFM) probe and a smooth surface as a function of separation, relative humidity (RH), and tip hydrophilicity. Completely wetting AFM tips exhibit a maximum in the capillary force as the RH increases, while the magnitude of the capillary force in the presence of partially wetting and partially drying tips is relatively independent of the RH. Capillary forces can also be significant in low RH environments and should not be discounted in AFM studies involving hydrophilic surfaces. [ABSTRACT FROM AUTHOR]

Hard spheres are a central and important model reference system for both homogeneous and inhomogeneous fluid systems. In this paper we present new high-precision molecular-dynamics computer simulations for a hard sphere fluid at a planar hard wall. For this system we present benchmark data for the density profile p(z) at various bulk densities, the wall surface free energy j, the excess adsorption Г, and the excess volume ve x, which is closely related to Г. We compare all benchmark quantities with predictions from state-of-the-art classical density functional theory calculations within the framework of fundamental measure theory. While we find overall good agreement between computer simulations and theory, significant deviations appear at sufficiently high bulk densities. [ABSTRACT FROM AUTHOR]

Some details of the research in thermodynamics of capillary systems, conducted at the Department of Physical Chemistry at Sofi a University “St. Kliment Ohridski “in the years 1970 - 1990, are presented in this article. The second part of the article analyzes some changes in research caused by major political changes in Europe and worldwide since 1990. [ABSTRACT FROM AUTHOR]

A thermodynamic method based on surface thermodynamics and atomic bond energy was developed to accurately investigate the lattice distortion rates of metallic nanomaterials. The results indicated that the lattice distortion rates of nanomaterials follow an inverse proportional relationship with the size, in good agreement with the experimental results. In this method, the anisotropy of the lattice distortion was a considerable issue. We found that the surface tension and Young's modulus of the nanocrystals, compared with those of the bulk materials, change because of the lattice distortion and exhibit a linear relationship at the nanoscale. By defining a shape factor (ξ), the lattice distortion rates of nanoparticles, nanowires, and nanofilms were calculated. This method provides a new approach for the evaluation of the lattice distortion rates in nanomaterials. [ABSTRACT FROM AUTHOR]

The inhomogeneous structure of a fluid at a wall can be characterised in several ways. Within a thermodynamic description, the surface free energy γ and the excess adsorption Γ are of central importance. For theoretical studies, closed expression of γ and Γ can be very valuable; however, even for a well-studied model system such as a hard-sphere fluid at a planar hard wall, the accuracy of existing expressions for γ and Γ, compared to precise computer simulation data, can still be improved. Here, we compare several known expressions for γ and Γ to the most precise computer simulation data. While good agreement is generally found at low to intermediate fluid densities, the existing parameterisations show significant deviation at high density. In this work, we propose new parameterisations for γ and Γ that agree with the simulation data within statistical error over the entire fluid density range. [ABSTRACT FROM PUBLISHER]

The main problem in electrocapillarity of solid electrodes is the lack of clarity in determining the surface stress and basic equations. Within the framework of the Gibbs concept of geometrical dividing surface, the 'surface stress' cannot be defined because methods of continuum mechanics can be applied to a physical surface layer (of finite thickness), but not to a mathematical surface. Gibbs never used the concept of surface stress, introducing only 'surface tension' for a liquid electrode and 'closely related quantity' for a solid electrode. Revisiting the derivation of the Gibbs adsorption equation, we prove its applicability to solid surfaces without the limiting requirement of constant state of strain, which was undeservedly interpreted by Eriksson as a shortcoming of the Gibbs theory caused to look for other approaches to surface stress problem. A critical analysis shows that the attempts (Shuttleworth, Eriksson, Couchman, Gokhstein, Weissmüller, etc.) to create a thermodynamic definition of the surface stress (as well as the formulation of fundamental thermodynamic equations and Maxwell relations operating with surface stresses) contain mathematical defects. It is shown that confusing interpretations of some Gibbs' concepts encountered in the literature have led to 'modifications' of the Lippmann equation based on the critical error in the Gibbs-Duhem relation due to the occurrence of an extensive variable, which is inadmissible. The famous Lippmann equation should not be modified, and it remains a unique electrocapillary relation applicable to liquid and solid electrodes. [ABSTRACT FROM AUTHOR]

It is shown that the so-called 'equation of solid-state electrocapillarity' derived by Gokhshtein from the simplest thermodynamic model, earlier used by Lippmann, is an incorrect modification that is returned to the classic Lippmann equation if to take into account the usual definition of differential capacity of the electrical double layer. Consequently, Gokhshtein's experiments can actually confirm only the validity of the Lippmann equation (with deviations caused by physicochemical processes in the double layer, which could not be taken into account in the thermodynamic equations). The thermodynamic model is insufficient for the interpretation s of these experimental results, whose understanding requires physical models of the different phenomena occurring at the electrode surface. [ABSTRACT FROM AUTHOR]

Abstract: Helfrich model of membrane bending elasticity has been most influential in establishment and development of Soft-Matter Physics of lipid bilayers and biological membranes. Recently, Helfrich theory has been extensively used in Cell Biology to understand the phenomena of shaping, fusion and fission of cellular membranes. The general background of Helfrich theory on the one hand, and the ways of specifying the model parameters on the other, are important for quantitative treatment of particular biologically relevant membrane phenomena. Here we present the origin of Helfrich model within the context of the general Gibbs theory of capillary interfaces, and review the strategies of computing the membrane elastic moduli based on considering a lipid monolayer as a three-dimensional thick layer characterized by trans-monolayer profiles of elastic parameters. We present the results of original computations of these profiles by a state-of-the-art numerical approach. [Copyright &y& Elsevier]

Highlights: [•] We evaluate thermodynamic stability of oxidized phospholipids in model membranes. [•] We evaluate the kinetic rate of phospholipid desorption from model membranes. [•] We probe the effect of oxidized phospholipids on endothelial permeability. [•] We propose a model for acute lung injury progression incorporating our results. [Copyright &y& Elsevier]

Highlights: [•] Surface tension of binary mixtures of alcohol/DMSO determined. [•] Surface mole fraction and surface thermodynamic parameters were calculated. [•] The surface tension data of binary mixtures were correlated with FLW, LWW and MS models. [ABSTRACT FROM AUTHOR]

Abstract: The size selection in quantum dot growth can be controlled by using the ion beam assisted deposition (IBAD) technique, as is previously demonstrated in experiments. Especially, in Ge/Si growth IBAD enhances the 2D to 3D transition and results a narrow size distribution compared to conventional deposition. We study size selection under IBAD using a continuous growth model with size dependent kinetics and thermodynamics. We show that ion beam assisted deposition exhibits stationary state of growth with uniform quantum dot size distributions. Finally we compare the results with nucleation theoretical predictions. [Copyright &y& Elsevier]

Abstract: Although a crack is a typical detail of a real solid, the theory of cracks in surface science was reduced to studying flat-parallel slits for a long time. The last decade has brought a number of new results related to the thermodynamic and surface science fundamentals of wedge-shaped cracks including the crack line tension. These results, essentially correcting and developing the theory of cracks, could not yet be included in the previous reviews of the author [A.I. Rusanov, Surf. Sci. Rep. 23 (1996) 173–247 and A.I. Rusanov, Surf. Sci. Rep. 58 (2005) 111–239] and make a subject for reviewing in this paper. Surface characteristics of a crack are described including the crack line tension as a new property that can be important for nanocracks. General thermodynamic relationships are derived, and the calculation of the thermodynamic surface and line tensions for solids with dispersion forces is given as an example. The dependence of the crack line tension on the crack size is analyzed for the conformal change (when a crack changes its size with maintaining its geometrical similarity) and the depth growth (when the distance between the crack lips is fixed). The latter has been found to be more favorable energetically. Since the presence of a crack is more probable for a loaded body, a general and rigorous approach to the thermodynamic description of loaded solids is presented including correcting earlier mistakes and terminology. The thermodynamic consideration presented outputs a useful contribution to the theory of solid strength. A generalized brittle fracture criterion is deduced and the ultimate strength is calculated for both the above mechanisms of the crack growth. The influence of the line tension on the ultimate strength is estimated both for the 2d and 3d cases. [Copyright &y& Elsevier]

Abstract: We report on a mechanism that under an off-normal incident ion beam, ordered nanodroplets may emerge spontaneously from a flat solid surface and line-up into chains perpendicular to the beam direction, forming a highly ordered hexagonal pattern. This behavior is in contrast to the general belief that an off-normal bombardment produces surface ripples, while the formation of dots requires either normal bombardment or off-normal bombardment with simultaneous sample rotation. The self-assembled nanodroplets reveal a mechanism different from the usual sputtering process. We propose a continuum theory which shows that the balance of mass flux plays an important role for the hexagonal pattern formation while the shadow effect causes the droplets to align into chains. The simulations suggest that the fundamental mechanism may be applicable to other systems, which may lead to an effective approach for nanofabrication. [Copyright &y& Elsevier]

Grain boundary (GB) grooving, induced by surface drift-diffusion and driven by the combined actions of capillary forces and applied uniaxial tensile stresses, is investigated in bi-crystal thin films using self-consistent dynamical computer simulations. A physico-mathematical model, based on the irreversible thermodynamics treatment of surfaces and interfaces with singularities allowed auto-control of the otherwise free-motion of the triple junction at the intersection of the grooving surface and the GB, without having any a priori assumption on the equilibrium dihedral angles. In the present theory, the generalised driving forces for stress-induced surface drift-diffusion arise not only from the usual elastic strain energy density (ESED), but also much stronger elastic dipole tensor interactions (EDTI) between the applied stress field and the mobile atomic species situated at the surface layer and in the GB regions. Accelerated groove-deepening kinetics shows that the surface drift-diffusion enhanced by the applied uniaxial tensile stresses through EDTI is dominant over the GB flux leakage at the triple junction. At high uniaxial stress levels (≥500 MPa for a 100-nm thick copper film), a sequential time-frame for micro-crack nucleation and growth is recorded just before specimen failure took place. These non-equilibrium thermokinetics discoveries (kinetics and energetics) contradict or at least do not support the hypothesis of the steady-state diffusive GB micro-crack formation and propagation due to ‘constant’ flux drainage through GB enhanced by tensile stresses acting normal to it. [ABSTRACT FROM PUBLISHER]

Abstract: In the present work, a generalized lattice-gas model to study multilayer adsorption of interacting polyatomic species on heterogeneous surfaces is introduced. Using an approximation in the spirit of the well-known Brunauer–Emmet–Teller (BET) model, a new theoretical isotherm is obtained in one- and two-dimensional lattices and compared with Monte Carlo simulation. In addition, the BET approach is used to analyze these isotherms and to estimate the monolayer volume. In all cases, the application of the BET equation leads to an underestimate of the true monolayer capacity. However, significant compensation effects were observed for heterogeneous surfaces and attractive lateral interactions. [Copyright &y& Elsevier]

Abstract: The monolayer adsorption of interacting binary mixtures on 2D square lattices has been studied through grand canonical Monte Carlo simulation in the framework of the lattice-gas model. The process has been monitored through total and partial isotherms and differential heats of adsorption corresponding to both species of the mixture. Repulsive lateral interactions between the adsorbed particles have been considered, resulting in a rich variety of structural orderings in the adlayer. At the end of this work, the phase diagram characterizing the transitions occurring in the system has been determined. A nontrivial interdependence between the partial surface coverage of both species was observed and discussed. [Copyright &y& Elsevier]

Abstract: The adsorption of lead (Pb) atoms on the clean Si(001)c(4×2) reconstructed surface as a function of the adatom coverage is investigated using density functional theory. It is shown that the growth of Pb adatom chains from the most stable monomer configuration, the end-dimer-bridge configuration, proceeds via the formation of inter- and intra-row ad-dimers, and ad-trimers. The calculated energetics of long Pb chains show that the most thermodynamically stable chains are composed exclusively of inter-row dimers, and that monomer termination of these chains is favoured over termination by a dimer. [Copyright &y& Elsevier]

Context: Oral administration of insulin is severely limited by very low bioavailability. Biocompatible polymeric nanocarriers have been investigated to overcome this problem. Flow focusing (FF) has revolutionized current engineering of poly(D,L-lactide-co-glycolide) (PLGA) based micromedicines. This technique has never been used to formulate insulin-loaded PLGA microparticles. Objective: Investigation of the benefits rising from the synthesis of insulin-loaded PLGA microplatforms by FF, compared to double emulsion/solvent evaporation method. Materials and methods: Both synthesis methodologies were compared in terms of geometry, surface physicochemical properties and insulin vehiculization capabilities. The stability of the peptide during the formulation procedure was further analysed. Results: FF permitted the preparation of insulin-loaded microcarriers with better geometry and physicochemical properties for the oral route, along with greater insulin loading capabilities and sustained insulin release kinetics. Discussion and conclusion: Results have lead to the identification of the best formulation conditions for the engineering of insulin-loaded PLGA microparticles against diabetes. [ABSTRACT FROM AUTHOR]

Abstract: The mixing behaviour of liquid Sb–Sn alloys has been described in terms of energetics and structure through the study of their thermodynamic, surface, transport and structural properties by using the Complex Formation Model (CFM) in the weak interaction approximation and by postulating SbSn chemical complexes as energetically favoured. The new Sb–Sn surface tension experimental data, obtained by the pinned drop method at temperatures ranging from 513 to 1023K, have been analysed in the framework of the CFM and compared with the calculated values as well as with the corresponding literature data. The structural characteristics of Sb–Sn melts are described by the two microscopic functions, i.e. the concentration fluctuations in the long-wavelength limit and the Warren–Cowley short-range order parameter. [ABSTRACT FROM AUTHOR]

Abstract: Upon initial microbial adhesion to a surface, multiple events occur that include interfacial re-arrangements in the region between an adhering organism and a surface. Application of physico-chemical mechanisms to explain microbial adhesion to surfaces requires better knowledge of the interfacial re-arrangement occurring immediately after adhesion than hitherto available. [ABSTRACT FROM AUTHOR]

Abstract: We have determined the step edge free energy, the step edge stiffness and dimensionless inverse step edge stiffness of the highly kinked <010> oriented step on a (001) surface of a simple square lattice within the framework of a solid-on-solid model. We have found an exact expression for the step edge free energy in the case that only nearest neighbour interactions are taken into account. At low temperatures the dimensionless inverse step edge stiffness reduces to the universal value . However, with increasing temperature the dimensionless inverse step edge stiffness increases. Incorporation of an attractive next-nearest neighbour interaction leads to a suppression of the dimensionless inverse step edge stiffness. For a non-zero next-nearest neighbour interaction the dimensionless inverse step edge stiffness even vanishes at zero temperature. [Copyright &y& Elsevier]

Abstract: This work is focused on the analysis of the effect of basic physicochemical aspects (surface thermodynamic and electrokinetic characteristics) on the stability and redispersibility properties of mebendazole aqueous suspensions. To our knowledge, previous investigations on the formulation of mebendazole suspensions have been not devoted to the elucidation of the colloidal behavior of this benzimidazole carbamate. A deep thermodynamic and electrokinetic characterization, considering the effect of both pH and ionic strength, was carried out with that purpose. It was found that the hydrophobicity and, the surface charge and electrical double layer thickness of the drug play a significant role in the stability of the colloid. Mebendazole aqueous suspensions display a controllable “delayed” or “hindered” sedimentation and a very easy redispersion which may contribute to the formulation of veterinary liquid dosage forms. [Copyright &y& Elsevier]

Abstract: We discuss the size selection of metallic 2D clusters in cases where the growth proceeds on flat or wedged surfaces. The growth of nanoclusters is modelled using reaction kinetic model rate equations, where the kinetics are described by size dependent attachment and detachment rates, and the energetics are described through the free energy difference of the clusters. The model describes how the optimum stationary size and small size dispersion are reached, and what are the properties of the stationary size distribution. In addition to the geometrical factors, it is shown that the deposition flux can also be used to tune the size distribution towards the desired property. [Copyright &y& Elsevier]

Abstract: According to the aim to compose combinatorial material by adsorption of carbon nanotubes onto the structured CeO2 surface the interaction of the armchair (5,5) and zigzag (8,0) nanotubes with the (001) and (111) surfaces of CeO2 islands have been investigated by theoretical methods. The thermodynamics of the adsorption were studied at the low surface coverage region. The interaction energy between the nanotube and the different CeO2 surfaces shows significant increase when the size of the interface reaches 7–8 unit cells of CeO2 and it remains unchanged in the larger interface region. However, the entropy term of the adsorption is significantly high when the distances of CeO2 islands are equal to 27nm (adsorption of armchair (5,5) nanotube) or 32nm (adsorption of zigzag (8,0) nanotube). This property supports adsorption of nanotubes onto CeO2 surfaces which possesses a very specific surface morphology. A long-wave vibration of nanotubes was identified as background of this unexpected phenomenon. This observation could be applicable in the development of such procedures where the nanotube adsorption parallel to the surface is aimed to perform. [Copyright &y& Elsevier]

Abstract: The initial stages of cluster nucleation for Pd or Ir adatoms on a W (110) surface and in the vicinity of surface steps are directly imaged by a field ion microscope (FIM). Three types of structures are observed. One is a one-dimensional linear chain, which is parallel to the nearest neighbor-stacking directions of the substrate. Another is a two-dimensional compact island, which is a pseudomorphic structure like the substrate. The other is a three-dimensional cluster, which shows a structural transition from bcc (110) to fcc (111). Factors affecting the structural transformation include coverage of atoms or atom chains, temperature of heat treatments and boundary of the substrate terrace. [Copyright &y& Elsevier]

Abstract: The study of the thermodynamic and the surface properties of liquid Cu–B alloys can help better understanding of a complex interfacial chemistry related to liquid Cu–brazes in contact with boride substrates. Despite a simplicity of the Cu–B phase diagram, only a few thermodynamic data are available in the literature, while in the case of the surface properties a complete lack of data is evident. The quasi-chemical approximation (QCA) for the regular solution has been applied to describe the mixing behaviour of liquid Cu–B alloys in terms of their thermodynamic and surface properties as well as the microscopic functions. In view of joining processes related to liquid Cu–brazes/solid boride systems a particular attention is paid to the surface properties of the Cu-rich part of the system and the calculated values are substantiated by the new surface tension experimental data of liquid Cu and Cu–10at.% B alloy. The tests have been performed by the sessile-drop method under the same experimental conditions. Considering the experimental uncertainties, the effect of oxygen on the surface tension of liquid Cu and Cu–10at.% B alloy has been analysed by simple model that combines the physical property data included in Butler’s equation with the oxygen solubility data and it gives the same results as Belton’s adsorption equation. [Copyright &y& Elsevier]

• Filamentous bacteria evolved the hdtS gene to trigger quorum sensing by C 6 HSL. • Changes in EPS induced by quorum sensing inhibited microbial aggregation. • Protein within EPS became tighter, preventing exposure of inner hydrophobic groups. • Bacteria overcome a stronger electrostatic and surface energy barrier to adhere. • Filamentous bulking were significantly inhibited by the quorum sensing inhibitor. The microcosmic mechanisms underlying filamentous bulking remain unclear. The role of extracellular polymeric substances (EPS) governed by quorum sensing (QS) in deteriorating sludge floc stability and structure during filamentous bulking and the feasibility of using quorum quenching (QQ) to maintain sludge floc stability and structure and sludge settling were investigated in this study. The results indicated that the concentration of C 6 HSL increased from 22.08±3.22 ng/g VSS to 81.42±5.98 ng/g VSS during filamentous bulking. The filamentous bacteria gradually evolved the hdtS gene related to the synthesis of C 6 HSL with increases in the population density. Triggered QS by filamentous bacteria proliferation induced variation in the composition and structure of EPS within the sludge flocs. The proteins (PN) content of the EPS increased evidently from 40.06 ± 2.41 mg/g VSS to 110.32 ± 4.32 mg/g VSS, and the polysaccharides (PS) content slightly increased during filamentous bulking. The upregulated proteins in the EPS led to a decrease in the relative hydrophobicity of the sludge and an increase in negative surface charge. The α-helix/(β-sheet+random coil) ratio evidently increased from 0.76 to 0.99 during filamentous bulking, revealing that the proteins were tightly structured, which prevented the exposure of inner hydrophobic groups. The total energy of the interaction (W T) between bacteria increased during sludge bulking, which resulted in the weakening of sludge aggregation. Variation in the physicochemical properties of EPS induced by QS in the filamentous bacteria markedly restrained adhesion between the filamentous bacteria and floc-forming bacteria. The production of PN in the EPS and the expression of the hdtS gene were inhibited by vanillin, which served as a QS inhibitor. The W T between bacteria with 50 mg/L of vanillin basically did not change. Filamentous bulking was significantly inhibited by the addition of vanillin. Therefore, QQ is a potential strategy for the prevention and control of filamentous bulking. This study provides new information regarding the microcosmic mechanisms of filamentous bulking. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Currently, great efforts are devoted to the design of drug delivery systems and many new polymers are investigated to make drug release fit the desired profiles. In this work, we investigate the formulation of colloidal aqueous suspensions based on the polymer Kollidon® SR for the oral administration of drugs. Such an investigation has never been carried out to our knowledge, as this polymer has only been used as soluble binder and film-forming agent for solid dosage forms. In this work, both the stability and redispersibility characteristics of Kollidon® SR aqueous suspensions are extensively investigated through thermodynamic and electrokinetic studies. The hydrophilic character of the polymer, and the surface charge and electrical double layer thickness play a key role in the stability of the suspensions, hence the need for a full characterization of the polymer. Kollidon® SR suspensions display a “free-layered” sedimentation determined by their hydrophilic character and their zeta potential values (indicating the electrokinetic charge on the particles). The electrostatic repulsion between the particles is responsible for the low sedimentation volume and easy redispersibility of the polymer. [Copyright &y& Elsevier]

Abstract: A simple statistical mechanical approach for studying multilayer adsorption of interacting rigid molecular chains of length k (k-mers) has been presented. The new theoretical framework has been developed on a generalization in the spirit of the lattice-gas model and the classical Bragg–Williams (BWA) and quasi-chemical (QCA) approximations. The derivation of the equilibrium equations allows the extension of the well-known Brunauer–Emmet–Teller (BET) isotherm to more complex systems. The formalism reproduces the classical theory for monomers, leads to the exact statistical thermodynamics of interacting k-mers adsorbed in one dimension, and provides a close approximation for two-dimensional systems accounting multisite occupancy and lateral interactions in the first layer. Comparisons between analytical data and Monte Carlo simulations were performed in order to test the validity of the theoretical model. The study showed that: (i) the resulting thermodynamic description obtained from QCA is significantly better than that obtained from BWA and still mathematically handable; (ii) for non-interacting k-mers, the BET equation leads to an underestimate of the true monolayer volume; (iii) attractive lateral interactions compensate the effect of the multisite occupancy and the monolayer volume predicted by BET equation agrees very well with the corresponding true value; and (iv) repulsive couplings between the ad-molecules hamper the formation of the monolayer and the BET results are not good (even worse than those obtained in the non-interacting case). [Copyright &y& Elsevier]

Abstract: We show that three independent derivations of the Shuttleworth equation, arguably the second most important equation in surface physics, are inconsistent with Hermann’s mathematical structure of thermodynamics [R. Hermann, Geometry, Physics and Systems, Marcel Dekker Inc., New York, USA, 1973 (Chapter 6)]. The possible implications of this result are discussed. [Copyright &y& Elsevier]

Abstract: The effects of surface confinement on the kinetics of ordering in fcc alloy films are studied by the Monte Carlo method. Under weak surface confinement, there are two kinds of kinetic path for alloy films with even layer. One is the films directly relaxing to the equilibrium state, the other is the films relaxing to a metastable state first. Even for the same initial atomic configuration, the kinetic path of ordering is randomized, and the possibility that the films relax to a metastable state is independent with the initial atomic configurations. We attribute this randomicity to the competition between surface confinement and chemical ordering. The evolution of the metastable state to the equilibrium state is also simulated. The results indicate that an alloy film with weak surface segregation can easily be trapped into metastable state. [Copyright &y& Elsevier]