Search results for "liquid"
showing 10 items of 4351 documents
On the measurement of local gas hold-up, interfacial area and bubble size distribution in gas–liquid contactors via light sheet and image analysis: I…
2013
Abstract In this work a novel experimental technique for measuring local gas hold-up, interfacial area and bubble size distribution, in gas–liquid systems is proposed. The technique is based on advanced Image Processing coupled with experimental set-ups typically available for Particle Image Velocimetry. A fluorescent dye dissolved in the liquid phase allows to identify in-plane bubbles among all visible bubbles in the images. To this end, a suitable algorithm is proposed. The raw data so obtained are processed by previously developed statistical methods that result in a reliable reconstruction of actual dispersion properties. The technique is applied to the case of a gas-dispersed mechanic…
Combined effect of solvent content, temperature and pH on the chromatographic behaviour of ionisable compounds.
2008
The organic solvent content and the pH in the mobile phase are the usual main factors in reversed-phase liquid chromatographic separations, owing to their strong effects on retention and/or selectivity. Temperature is often neglected. However, even in cases where the impact of this factor on selectivity is minor, the reduction in analysis time is still an interesting reason to consider it. In addition, ionisable compounds may exhibit selectivity changes, owing to the interaction of organic solvent and/or temperature with pH. The separation of ionisable compounds (nine diuretics: bendroflumethiazide, benzthiazide, bumetanide, chlorthalidone, furosemide, piretanide, probenecid, trichloromethi…
Solid–Liquid Suspensions in Top-Covered Unbaffled Vessels: Influence of Particle Size, Liquid Viscosity, Impeller Size, and Clearance
2014
Particle suspension in liquids is a unit operation commonly encountered in the process industry. Although it is usually carried out in baffled stirred tanks, there are some specific applications where the presence of baffles may be undesirable. In the present work solid-liquid suspensions are investigated in a radially stirred unbaffled tank provided with a top cover. The minimum impeller speed at which all solid particles get suspended (Njs) and the relevant power requirements (Pjs) are assessed. The dependence of these two parameters on physical properties (liquid viscosity, particle concentration, and size) and system geometrical configurations (impeller diameter and clearance) is invest…
Testing experimental designs in liquid chromatography (I): Development and validation of a method for the comprehensive inspection of experimental de…
2020
The basis of interpretive optimisation in liquid chromatography is the prediction of resolution, from appropriate solute retention models. The reliability of the process depends critically on the quality of the experimental design. This work develops, validates and applies a general methodology aimed to evaluate the quality of any training experimental design, which will be applied in Part II to design optimisation. The methodology is based on the systematic evaluation of the uncertainties associated to the prediction of retention times in comprehensive scans of both isocratic and gradient experimental conditions. It is able to evaluate comprehensively experimental designs of arbitrary comp…
Comparison of two serially coupled column systems and optimization software in isocratic liquid chromatography for resolving complex mixtures.
2012
Although there is a great deal of stationary phases having different selectivities (even practically orthogonal selectivities), these very rarely are taken as a factor to be optimized during method development. The chromatographer selects the stationary phase usually in a trial-and-error fashion (or based on the solute nature and expected interactions), and then optimizes continuous factors as the mobile phase composition, pH, temperature and flow-rate. However, the optimization of the stationary phase nature and column length (which are discrete factors) may be interesting. In this regard, the optimization of the coupling of individual columns may yield separations that are not possible wi…
Experimental Determination and Correlation of Liquid–Liquid Equilibria Data for a System of Water + Ethanol + 1-Butyl-3-methylimidazolium Hexafluorop…
2017
Over the past few years, interest has increased regarding the application of ionic liquids (ILs) as extraction solvents for separating azeotropic mixtures. Following this trend, this work presents the experimental data of liquid–liquid equilibria (LLE) of the system envolving water, ethanol, and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) at different temperatures. The LLE data of the system was measured between 283.2 and 323.2 K to determine the temperature influence on the system. In the literature, reports of systems involving ILs that present type II behavior are scarce compared with those that present type I behavior; the system presented here also displays two immisc…
Liquid–liquid equlibria of the system dimethyl carbonate+methanol+water at different temperatures
2006
Abstract In this work, experimental liquid–liquid equilibria (LLE) data of the dimethyl carbonate + methanol + water system are presented. The LLE of this system has been measured from 283 to 333 K. On the other hand, LLE and LVE of the binary system dimethyl carbonate + water have been measured. The equilibrium data presented are correlated using NRTL and UNIQUAC equations. The reliability of these models is tested by comparison with experimental results. Finally, the VLE for the system DMC + water at 101.3 kPa was predicted using the UNIQUAC model, with the adjusted parameters obtained from the LLE data. This prediction was successful when is compared with the experimental VLE data.
Liquid–liquid equlibria of the mixture linalool+ethanol+water at different temperatures
2005
Abstract In this work, experimental liquid–liquid equilibria (LLE) data of the linalool + ethanol + water system are presented. The LLE of this system has been measured at 293.15, 303.15, 313.15 and 323.15 K. The equilibrium data presented are correlated using NRTL and UNIQUAC equations. Finally, the reliability of these models is tested by comparison with experimental results.
Measurements and correlation at different temperatures of liquid–liquid equilibria of 2-butanol or 2-methyl-2-butanol+1,2,3-propanetriol+water ternar…
2014
Abstract In this work, the experimental liquid–liquid equilibria (LLE) data of 2-methyl-2-butanol + 1,2,3-propanetriol (glycerol) + water and 2-butanol + 1,2,3-propanetriol (glycerol) + water systems at different temperatures are presented. The LLE of the systems has been measured between 283 and 323 K. The NRTL and UNIQUAC models were applied to the ternary systems. The interaction parameters obtained from both models successfully correlated the equilibrium compositions. The experimental tie lines were compared to the values predicted by the UNIFAC method. Finally, the solvent capability of both alcohols was checked in order to separate the mixture formed by glycerol and water.
Narrow Band Solid-Liquid Composite Arrangements: Alternative Solutions for Phononic Crystal-Based Liquid Sensors
2019
Periodic elastic composite structures attract great attention. They offer the ability to design artificial properties to advance the control over the propagation of elastic/acoustic waves. In previous work, we drew attention to composite periodic structures comprising liquids. It was shown that the transmission spectrum of the structure, specifically a well-isolated peak, follows the material properties of liquid constituent in a distinct manner. This idea was realized in several liquid sensor concepts that launched the field of phononic crystal liquid sensors. In this work we introduce a novel concept&mdash