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A diffuse interface model for solid-liquid-air dissolution problems based on a porous medium theory

A diffuse interface model for solid-liquid-air dissolution problems based on a porous medium theory

Conclusions A diffuse interface model (DIM) is proposed to simulate the solid-liquid-gas three phase dissolution problems. The solid-liquid interface is diffused by the local non- equilibrium porous medium model, while the liquid-gas interface is diffused by the artificial capillary effects. The simulation results show that this method is able to follow the moving of both the solid-liquid and liquid-gas interfaces. The solid-air interface will not move due to the absence of dissolution. Adaptive mesh refinement method can be also applied to this kind of problems with sharp fronts to improve the computational efficiency.
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Thermodynamic study of solid-liquid-vapor equilibrium : application to cryogenics and air separation unit

Thermodynamic study of solid-liquid-vapor equilibrium : application to cryogenics and air separation unit

The pressure-explicit functional form of the Yokozeki EoS introduces a discontinuity in the solid-liquid transition, and allows evaluating the non ideality in all the phases (solid, liquid, and vapor) in terms of fugacity coefficient. Furthermore, different attractive terms can be considered. A rigorous procedure for calculating the pure compound parameters has been established; the capability of the Yokozeki EoS with different attractive terms in qualitatively representing equilibrium properties of argon has then been challenged. Limitations have mainly been found with respect to solid-liquid equilibrium densities and latent heats of transition. Based on this comparison, the attractive term of the van der Waals EoS has been considered in the functional form of the Yokozeki EoS as the best compromise for quantitatively representing the phase equilibrium data (pressure and temperature) and qualitatively representing densities and latent heats of transition. As a result, the model used in this work (renamed Solid-Liquid-Vapor EoS) has the same functional form used by A. Yokozeki, but differently from his works the EoS parameters for the pure compounds are regressed considering also solid-liquid, vapor-liquid, and solid-vapor equilibrium values obtained from auxiliary equations.
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Adsorption of Hyperbranched Arabinogalactan-Proteins from Plant Exudate at the Solid–Liquid Interface

Adsorption of Hyperbranched Arabinogalactan-Proteins from Plant Exudate at the Solid–Liquid Interface

michael.nigen@supagro.inra.fr (M.N.); christian.sanchez@supagro.inra.fr (C.S.) 3 BIBS, INRA, F-44300 Nantes, France; angelina.d’orlando@inra.fr * Correspondence: denis.renard@inra.fr; Tel.: +33-2-40-67-50-52 Received: 24 April 2019; Accepted: 15 May 2019; Published: 17 May 2019    Abstract: Adsorption of hyperbranched arabinogalactan-proteins (AGPs) from two plant exudates, A. senegal and A. seyal, was thoroughly studied at the solidliquid interface using quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR), and atomic force microscopy (AFM). Isotherms of the adsorption reveal that 3.3 fold more AGPs from A. seyal (500 ppm) are needed to cover the gold surface compared to A. senegal (150 ppm). The pH and salt concentration of the environment greatly affected the adsorption behavior of both gums, with the surface density ranging from 0.92 to 3.83 mg m −2 using SPR (i.e., “dry” mass) and from 1.16 to 19.07 mg m −2 using QCM-D (wet mass). Surprisingly, the mass adsorbed was the highest in conditions of strong electrostatic repulsions between the gold substrate and AGPs, i.e., pH 7.0, highlighting the contribution of other interactions involved in the adsorption process. Structural changes of AGPs induced by pH would result in swelling of the polysaccharide blocks and conformational changes of the polypeptide backbone, therefore increasing the protein accessibility and hydrophobic interactions and/or hydrogen bonds with the gold substrate.
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Exploring catalytic solid/liquid interfaces by in situ attenuated total reflection infrared spectroscopy

Exploring catalytic solid/liquid interfaces by in situ attenuated total reflection infrared spectroscopy

In situ attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy has gained considerable attention as a powerful tool for exploring processes occurring at solid/liquid and solid/liquid/gas interfaces as encountered in heterogeneous catalysis and electrochemistry. Understanding of the molecular interactions occurring at the surface of a catalyst is not only of fundamental interest but constitutes the basis for a rational design of heterogeneous catalytic systems. Infrared spectroscopy has the exceptional advantage to provide information about structure and environment of molecules. In the last decade, in situ ATR-FT-IR has been developed rapidly and successfully applied for unraveling processes occurring at solid/liquid interfaces. Additionally, the kinetics of complex reactions can be followed by quantifying the concentration of products and reactants simultaneously in a non-destructive way. In this tutorial review we discuss some key aspects which have to be taken into account for successful application of in situ ATR-FT-IR to examine solid/liquid catalytic interfaces, including different experimental aspects concerned with the internal reflection element, catalyst deposition, cell design, and advanced experimental methods and spectrum analysis. Some of these aspects are illustrated using recent examples from our research. Finally, the potential and some limitations of ATR will be elucidated.
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Solid -liquid extraction of andrographolide from plants  experimental study, kinetic reaction and model

Solid -liquid extraction of andrographolide from plants experimental study, kinetic reaction and model

Abstract Solidliquid extraction is performed from leaves and stems of Andrographis paniculata in ethanol–water solvent, in order to obtain andrographolide. The first part of this work concerns the acquisition of the raw plant geometric and physicochemical characteristics. Then batch experiments are done in order to study the influences of the operating parameters (temperature, nature of the solvent and particles size). Furthermore, the destruction of the solute with high temperature is also studied. In the last part, an two-shape extraction model is proposed and compared with experimental data. This model includes the shape factor of the particles population composed of stems and leaves (cylinders and plates).
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STUDY OF IN-PLANE SILICON NANOWIRES OBTAINED VIA A SOLID-LIQUID-SOLID GROWTH PROCESS AND THEIR SELF- ORGANIZATION FOR ELECTRONIC APPLICATIONS

STUDY OF IN-PLANE SILICON NANOWIRES OBTAINED VIA A SOLID-LIQUID-SOLID GROWTH PROCESS AND THEIR SELF- ORGANIZATION FOR ELECTRONIC APPLICATIONS

 F ABRICATION AND INTEGRATION OF ONE - DIMENSIONAL SEMICONDUCTORS In general, the methods for producing 1-D semiconductor nanostructures can be classified into two families: i) Top-down methods, based on a physical and/or chemical etching process of tailoring the bulk substrates into NWs laterally lying or vertically standing on the substrates; (ii) Bottom-up methods, which rely on growing processes catalysed or self-catalysed by collecting and organizing atomic sources (precursors) from a vapour, liquid or even solid phase, assisted by thin film deposition techniques such as chemical vapour deposition (CVD), plasma-enhanced chemical vapour deposition (PECVD), metalorganic chemical vapour deposition (MOCVD), molecular beam epitaxy (MBE), or via solution-based synthesis methods. The most popular bottom-up method is vapour-solid-liquid (VLS) growth process, based on the interaction of liquid metal droplets and atomic precursors from vapour phase and transforming them to solid crystalline phase. A variant of the VLS method is vapour-solid-solid (VSS) mode, where the metal catalysts are in solid phase. In this thesis, we will introduce another variant growth mode, called in- plane solid-liquid-solid mode [38], where liquid metal droplets (indium) move on substrates with a pre-coated layer of a-Si:H on top, absorb Si atoms from the a-Si:H layer at their advancing edge, and precipitate c-SiNW at their receding edge [39]. Numerous review articles on the growth methods and properties of semiconductor nanostructures have been published before [40]-[46], and a brief review of bottom-up growth techniques related with our growth method is presented in Chapter 2.
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Frictional stress formulation for solid-liquid two-phase flows

Frictional stress formulation for solid-liquid two-phase flows

Frictional Stress Formulation for Solid-Liquid Two-Phase Flows 1. INTRODUCTION Several two-phase flows of solids-liquids systems involve slow deformation or formation of stagnant regions of bulk granular materials. Such flows concern, for example, settling of tailings, deposition of solids in pipes, solids discharge through bins, and the formation of solids heaps. This behaviour poses a major difficulty to two-phase models. The main challenge remains to be modeling of the stresses within the granular phase for slow or stagnant regions.

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Study of nano-engineered solid-liquid interfaces based on polymer brushes and biomimetic multifunctional glue

Study of nano-engineered solid-liquid interfaces based on polymer brushes and biomimetic multifunctional glue

34 1.1.6. Conclusions We have shown here that solid / liquid interfaces (SLIs) play a crucial role in many different processes in biology, chemistry and physics. Along the same lines, we also put in the evidence that SLIs become extremely important for small objects, such as particles and/or nano- and micro-channels. This can be explained through scaling laws as the volume forces decay much faster than the surface ones, with decreasing size of an object. It has been well known for many years that SLIs play a crucial role in microfluidic devices and that their role will grow even more as we move to nano-fluidics. Consequently, several approaches to the modification of SLIs have been developed over the years and they are based on formation of more or less organized organic layers on a solid surface. We have described the major modification schemes of the SLIs, such as the formation of self- assembled monolayers on silicon and/or metal surfaces, formation of end-tethered polymers brushes and adsorption of neutral or charged polyelectrolytes on various surfaces. All these approaches have their advantages and disadvantages but they all can be characterized by the requirement of a surface specificity, i.e., the surface chemistry dictates the material of choice that will be modified. The situation becomes even more difficult or even impossible to realize when surfaces of microfluidic devices built from several different materials have to be functionalized.
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Biodegradation of endocrine disruptors in solid-liquid two-phase partitioning systems by enrichment cultures

Biodegradation of endocrine disruptors in solid-liquid two-phase partitioning systems by enrichment cultures

Partitioning Systems by Enrichment Cultures Richard Villemur, Silvia Cristina Cunha dos Santos, Julianne Ouellette, Pierre Juteau,* François Lépine, Eric Déziel INRS—Institut Armand-Frappier, Laval, Quebec, Canada Naturally occurring and synthetic estrogens and other molecules from industrial sources strongly contribute to the endocrine disruption of urban wastewater. Because of the presence of these molecules in low but effective concentrations in wastewaters, these endocrine disruptors (EDs) are only partially removed after most wastewater treatments, reflecting the presence of these molecules in rivers in urban areas. The development of a two-phase partitioning bioreactor (TPPB) might be an effective strategy for the removal of EDs from wastewater plant effluents. Here, we describe the establishment of three ED-degrading microbial enrichment cultures adapted to a solid-liquid two-phase partitioning system using Hytrel as the immiscible water phase and loaded with estrone, estradiol, estriol, ethynylestradiol, nonylphenol, and bisphenol A. All molecules except ethynylestradiol were degraded in the enrichment cultures. The bacterial composition of the three enrichment cultures was determined using 16S rRNA gene sequencing and showed sequences affiliated with bacteria associated with the degradation of these compounds, such as Sphingomonadales. One Rhodococcus isolate capable of degrading estrone, estradiol, and estriol was isolated from one enrich- ment culture. These results highlight the great potential for the development of TPPB for the degradation of highly diluted EDs in water effluents.
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Solid-Liquid Equilibria Modelling for triacylglycerols exhibiting multiple solid phases

Solid-Liquid Equilibria Modelling for triacylglycerols exhibiting multiple solid phases

to the equilibrium between a solid crystalline network and a liquid phase. This work presents the available literature development of solid-liquid equilibrium in triacylglycerol systems and highlights how it can be coupled with a Computer-Aided Mixture and Blend Design framework, for design new mixtures/blends with improved properties allowing a better use of renewable resources as vegetable oils. Stability tests were implemented as they are an essential step for powerful solid liquid equilibrium resolution and some results were presented for a four component triacylglycerol mixture in different temperatures and compositions.
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Distance Geometry: A Viewing Help for the Solid-Liquid Phase Transition in Small Systems

Distance Geometry: A Viewing Help for the Solid-Liquid Phase Transition in Small Systems

convolution products. This reduction is even exact at low energy. In any case, it is much easier to compute than an s-dimensional integral. The N = D = 3 case is especially interesting because it is possible to draw a represen- tation of the constant energy surface in the distance space. The accidents of the density of states as a function of energy (or rather of its logarithm, the entropy S(E)) can be vi- sualized and given a simple interpretation on this drawing. It is well known that accidents of S(E) are related to so-called phase transitions in clusters [6, 7, 8, 9]. The solidliquid transition (actually a phenomenon akin to this transition) has been observed both in simu- lations [6, 10, 11] and in experiments [12, 13, 14, 15, 16, 17]. We anticipate that the simple view given in this letter could be used in understanding the solidliquid transition in larger clusters as well.
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Axial acoustic field along a solid-liquid fluidized bed under power ultrasound

Axial acoustic field along a solid-liquid fluidized bed under power ultrasound

5. Conclusions A methodology has been developed for the acoustical character- ization of sonoreactors, based on FFT signal processing, allowing to distinguish the di fferent spectral components: driving frequency, (sub-/ ultra-)harmonics corresponding to the stable cavitation and broad-band noise associated to the inertial one. The effect of increasing emitting power on the ultrasound propagation has been studied and the results indicate a higher energy transfer from the fundamental wave toward the broad-band noise, as well as a shielding effect by the cavitation bubbles leading to a fast decrease of the total signal power with the distance from the emitter. Hence it shows that the emission power in any sonochemistry process has to be carefully chosen as higher power does not necessarily imply higher efficiency. A probable explanation of the liquid flow effect is the sweeping of the cavitation bubbles away from the zone in front of the horn. Technical restrictions indeed implied to design this reactor with ultrasound emitted against the flow, but it could be interesting to work in other con figurations to check if this trend would be then modified. The solid suspension brings additional attenuation, but it is much more difficult to conclude about the causes of the observed e ffects. In the light of the obtained results, this study could bene fit from the use of an emitting device able to generate ul- trasound at an intensity low enough to keep the medium below cavi- tation level (so as to uncouple for instance the respective e ffects of the
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From colloidal dispersions to colloidal pastes through solid/liquid separation processes

From colloidal dispersions to colloidal pastes through solid/liquid separation processes

The correspondence with a structure made of dense lumps dispersed in a uniform matrix can be examined quantitatively by using the structure factor from an equilibrium hard sphere liquid, which could approximate the matrix, and adding a contribution that represents the scattering from the lumps. Indeed, at volume fractions that match those of the cakes, hard sphere liquids have theoretical structure factor that is depressed low Q, due to the suppression of long wave length fluctuations by interparticle repulsions (see Fig 5). On the other hand, the scattering from the frozen concentration fluctuations (dense lumps) can be represented by a power-law decay at low Q. In this way, the experimental S(Q) of cakes compressed at 2 atm (φ = 0.1) can be reproduced by the linear combination of a Q –2 decay and the S(Q) for hard spheres at the same volume fraction. Similarly, the S(Q) of cakes compressed at 4 atm (φ = 0.23) is matched by the linear combination of a Q -4 decay and the theoretical structure factor for the hard sphere liquid at
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Axial acoustic field along a solid-liquid fluidized bed under power ultrasound

Axial acoustic field along a solid-liquid fluidized bed under power ultrasound

p bed bed (8) with m p the mass of the solid particles kg ( ), their density ρ kg m p ( . − 3 ) and S bed the cross-sectional area of the column m ( 2 ) . The results obtained for the fluidization of 2 mm glass beads in si- lent conditions are gathered in Fig. 7 . As a hysteresis behavior could be expected [35,36] , measurements have been performed with both an increasing and a decreasing fluid velocity. All the curves exhibit two distinct zones separated by a slope break; they correspond to the two states of the bed: fixed and fluidized. Under silent conditions, the ex- pansion and contraction curves are almost superimposed: the solid hold-up of the fixed bed is only very slightly higher with a gradually decreased flowrate, due to some rearrangement of the particles. The experimental data are also consistent with the Ergun equation for pressure drop in the fixed bed zone [37] , and that of Wen and Yu for solid hold-up in the fluidized bed zone [38] . The low increase of pressure drop in the latter region, observed in Fig. 7 B, is actually due to the fact that the lowest insert is not at the very base of the column. Thus the mass of solid present between the two pressure measurement points increases with the bed expansion, so does the measured pressure drop. It has been accounted for in the line curve shown in Fig. 7 B (using Wen and Yu ’s expression for solid hold-up).
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From colloidal dispersions to colloidal pastesthrough solid–liquid separation processes

From colloidal dispersions to colloidal pastesthrough solid–liquid separation processes

INTRODUCTION Dispersions of fine solid particles in a liquid are commonly used to manufacture coatings, composite materials, and ceramics. They are also encountered in foods, pharmaceuticals, and biotechnological processes. Lastly, they constitute the bulk of industrial and city effluents. In many cases, it is at some point necessary to separate the particles from the liquid. This is achieved through a variety of industrial processes, including drying, slip casting, pressure filtration, and centrifugation (Table 1). In all of these processes, it is generally recognized that the success of the operation depends on the control of inter- actions between particles. In many cases, however, there is no quantitative model for the relations be- tween colloidal interactions and the properties of the final product.
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Shear banding and the solid/liquid transition in yield stress fluids

Shear banding and the solid/liquid transition in yield stress fluids

Fontainebleau, sieved to have a radius between 90 and 110 µm), spherical glass beads of 25 and 100 µm radius, polystyrene beads of 100 µm radius (Dynoseeds, from Microbeads), and PMMA spheres of a 3 µm radius (Calibre, from Microbeads). All beads are thoroughly rinsed and dried before use. The fluids used are ultra pure water and silicone oil (Rhodorsil from CRC Industries France). The surface tensions of the fluids in presence of beads are determined using the Du Nuoy ring method. For water it is found to be 72 mN/m and 20 mN/m for silicone oil. After preparing a mixture of beads and fluid, a small quantity of this mixture is put in a vane-in-cup geometry in the rheometer. For the almost completely dry and almost completely wet mixtures the yield stress is quite low and the grains reach something resembling a close packing when just poured into the the rheometer geometry, but for the intermediate liquid volume fractions the yield stress is quite high and the material does not compact under its own weight, resulting in much lower grain packing fractions. In order to compare the elastic moduli at different liquid volume fractions and to get results not depending strongly on how the material is loaded into the cup, the material is after loading compacted by dropping a small thumper (12.5 mm in radius, 40 mm in height and with a 30 g mass) from a small height (about 10 mm) at least 100 times. I found that this ensures a reproducible compaction (a filling fraction of about 0.63 ± 0.01) for all liquid volume fractions and for each loading of the sample. This observation and the fact that the yield stresses of completely dry and wet materials were too low for their elastic moduli to be measured, demonstrates that the compaction of the materials does not squeeze the beads together in the cup. Since the capillary rise (h = 2γ cos θ/ρgr [182]) in the samples is at least 15 cm and thus much higher than the filling height, surface tension along with mechanical mixing prior to the experiment should prevent drainage and other inhomogeneities in the distribution of liquid among the grains.
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Coiling Instability in Liquid and Solid Ropes

Coiling Instability in Liquid and Solid Ropes

Spiral Bubble Pattern in Liquid Rope Coiling 4.1 Introduction The study of spirals in nature goes back a few centuries, when for instance Swammer- dam was one of the first to try and describe the beautiful forms of certain seashells [38]. The standard work on spontaneous pattern formation in Nature, Darcy Thomp- son’s ”On Growth and Form” [38] describes a multitude of spiral patterns; besides shells he discusses for instance spiral patterns of seeds in sunflowers, but also the helical structure of branches or leaves on a growing plant stem. All these spirals are self-organized, but still obey rather strict mathematical rules; shells are generally log- arithmic spirals in which the distance between successive loops grows in a precisely determined fashion with increasing distance from the center [39]. For phyllotaxis (the sunflower spirals), Douady and Couder [40] have shown with a clever laboratory experiment that the spirals form due to a self-organized growth processes: new seeds are generated at a fixed frequency in the center and through a steric repulsion repel each other; the maximization of the distance between the seeds then leads to a special subtype of logarithmic spiral pattern: the golden or Fibonacci spiral.
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Probing the local structure of pure ionic liquid salts with solid- and liquid-state NMR

Probing the local structure of pure ionic liquid salts with solid- and liquid-state NMR

and many others. Due to the enormous number of potential cation–anion combinations, it is impossible to investigate directly even a small fraction of the set of feasible ILs. Thus, to develop a mo- lecular understanding of their properties requires generaliza- tions from representative systems. Of primary concern and controversy is the nature of the liquid state, in particular the type and extent of molecular order present. Theories, and ex- perimental support, range from simple ion pairs to liquid-crys- tal-type order depending on the characterization technique employed, the IL under study, and the interpretation of the data. It appears that only two clear trends can be distinguished that result in increased order in the liquid state: increased alkyl substituent length on the cation, and smaller anions. Further- more, even where there is agreement with regards to the pres- ence of some kind of nanostructure, its nature is not yet fully agreed upon. For example, early studies led the investigators to report extended hydrogen-bonding networks, but subse- quent research has suggested that the type of bonding ob- served is not entirely consistent with the hydrogen-bonding model. [8]
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An automated flow platform for accurate determination of gas–liquid–solid reaction kinetics

An automated flow platform for accurate determination of gas–liquid–solid reaction kinetics

Introduction Gas –liquidsolid reactions, such as hydrogenation, oxidation and carbonylation, are widely used in the petroleum, 1,2 fine chemical, 3–9 agrochemical, 7,10 and pharmaceutical industries. 3,5,9,11 Accurate determination of gas –liquidsolid reaction kinetics is required for reactor design and process optimization, 12 and has the benefit of significantly increasing the selectivity to the product and improving process safety. Traditional methods for the determination of gas –liquidsolid reaction kinetics can be categorized as either sampling under steady-state conditions in flow or generating time-series data in batch. 13 Continuous flow experiments, especially in microreactors, have advantages of faster mixing time, lower catalyst cost, and intensification of heat and mass transfer. 12,14–18 However, the sampling is performed only when the flow system reaches a steady state (at least three
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An annotated bibliography on residential chimneys serving solid- or liquid-fuel fired heating appliances

An annotated bibliography on residential chimneys serving solid- or liquid-fuel fired heating appliances

Condensation from flue gas on inside surfaoes in relatively cold chFmneys is discussed and methods of lining chimneys to alleviate condensation trouble are given. For gas fuel, asbest[r]

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