Alcohol-water Mixtures Research Articles

基于光栅结构太赫兹谐振器的醇水混合液检测

基于光栅结构太赫兹谐振器的醇水混合液检测

Study of internal mechanisms for establishment of the equilibrium state of water-alcohol mixtures in vodka technology

Study of internal mechanisms for establishment of the equilibrium state of water-alcohol mixtures in vodka technology

Rapid, accurate, and precise concentration measurements of a methanol–water mixture using Raman spectroscopy

Here we design, construct, and characterize a compact Raman-spectroscopy-based sensor that measures the concentration of a methanol–water mixture with 0.5% accuracy. The sensor measures the concentration with a precision of 0.2% with a 1 second measuring time, and with longer measurement times, the precision reaches as low as 0.006%. We characterize the long-term stability of the instrument over an 11-day period of constant measurement, and confirm that systematic drifts are on the level of 0.02%. We describe methods to improve the sensor performance, providing a path towards accurate, precise, and reliable concentration measurements in harsh environments. This sensor should be adaptable to other water–alcohol mixtures, or other small-molecule liquid mixtures.

Development and creation a model of a digital twin of the cubepart rectification installation for the separation of a binary water-alcohol mixture

In article the way of creation of development of the digital twin of a cube part of a rectification column for the separation of a binary water-alcohol mixture, using the software Matlab/Simulink is considered. The technology solution on creation and verification of the digital twin of the available laboratory installation and structure of digital model, which is the basis for the digital twin, are developed.

Transport properties of fluids using new rough hard-sphere and molecular dynamics simulation

We have studied transport properties, as well as the self-diffusion, viscosity and thermal conductivity of fluids by using new semi-theoretical model based on the rough hard-sphere (RHS) theory. In the present study, the proposed RHS is employed to model the transport properties of CH4, CCl4, C6H6, CHCl3, H2O, R134a, 2-EHB, PE and PS for temperatures ranging from 110 to 530 K and at pressures up to 1000 MPa. Parameters appeared in the new RHS model are taken from previously developed perturbed hard-trimer chain (PHTC) equation of state. From 174 experimental data points examined, the average absolute relative deviation AARD of predicted viscosities for CH4, H2O and R134a was found to be 6.59%. In the case of self-diffusion, the new RHS-based model correlated and predicted 139 experimental data points with AARD equal to 4.06%. The proposed RHS-based model has also been extended to predicted 228 experimental data points of thermal conductivity for CH4, H2O and R134a with AARD equal to 4.54%. In addition, molecular dynamics (MD) calculations were performed with the GROMACS simulation package and to investigate the thermophysical properties of fluids. The MD approach enabled us to calculate the density, viscosity, self-diffusion and thermal conductivity of CH4 and C6H6. The computed value of these properties agreement with experimental values. Finally, MD is applied to calculate density of binary water–alcohol mixtures including water–methanol and water–ethanol.

Experimental investigation on spray cooling with low-alcohol additives

In the present study, the spray-wall impingement characteristics and heat transfer performance during spray cooling were experimentally investigated to ascertain the effect of different low-alcohol additives in water. The surface tension and contact angle on the heating surface were measured and the images of spray wall interaction were taken. The spray cooling performance of alcohol-water mixtures were compared with pure water. The results indicated that adding a small amount of alcohol to water can significantly decrease the surface tension and contact angle. It is also an effective way to enhance the heat dissipation and to control the surface temperature simultaneously. As the alcohol content increases, the intensity of heat transfer capacity enhancement increases first and then weakens slightly. The optimal concentrations of ethanol, n-propanol and iso-propanol corresponding to the best heat transfer performance are respectively 4 vol%, 4 vol% and 2 vol%, and the maximum heat transfer coefficient is achieved with 4 vol% ethanol-water mixture. The correlation of Nusselt number, which is associated with the physical properties, the Weber, Prandtl, Jacob as well as Reynolds numbers, is also presented with an error of 15%.

Composite Membranes with a Polyvinyltrimethylsilane Skin Layer for Separation of Water–Alcohol Mixtures

The paper presents the characteristics of a laboratory-made water-selective composite membrane with a selective layer of hydrophobic polyvinyltrimethylsilane (PVTMS) for use in the processes of vapor-phase membrane recovery of alcohols from dilute aqueous alcohol mixtures of biogenic origin. The support is a polyacrylonitrile ultrafiltration membrane, and the PVTMS skin layer of the resulting composite membrane has a thickness of 3 to 4 microns. The vapor transport and separation characteristics of the membrane for water–ethanol and water–butanol mixtures in the temperature range of 60–80°C have been studied. It has been shown that the membrane selectivity varies in the range of 23–39 for the water/ethanol pair or 100–140 for the water/butanol pair. A specific feature of the hydrophobic water-selective membrane as applied to the vapor-phase process is the stability of its characteristics due to the absence of swelling, in contrast to hydrophilic water-selective membranes whose characteristics substantially depend on the activity of water vapor. The process of vapor-phase membrane recovery of ethanol and butanol from dilute aqueous alcohol mixtures of biogenic origin with their initial concentrations of 10 and 1 wt %, respectively, has been mathematically modeled on the basis of the experimental data. The calculation results show that the composite membrane obtained makes it possible to concentrate ethanol and butanol to 95 and 98 wt % with degrees of recovery of more than 0.8 and more than 0.9, respectively.

Metamaterial inspired miniaturized SIW resonator for sensor applications

A planar substrate integrated waveguide (SIW) resonator is proposed in this letter. By loading a metamaterial inspired structure in a short section of an SIW, a miniaturized cavity (0.263 × 0.184 × 0.0063 λ03 at 2.39 GHz) with high quality factor (272.5) is obtained. The resonant modes of the cavity and their corresponding field distributions are analyzed. A resonator prototype has been fabricated and tested. The measured results agree well with the simulated ones. This cavity resonator has huge potential in sensor applications. A binary solvent water alcohol mixture is used to verify the sensor concept.

Study of Short-Chain Alcohol and Alcohol-Water Adsorption in MEL and MFI Zeolites.

In this paper, we present a comparative study of the adsorption behavior of short chain alcohols (pure and in aqueous solution) into silicalite-1 (MFI-type zeolite) and silicalite-2 (MEL-type zeolite). For quite some time, silicalite-1 has been the reference material to address the problem of adsorptive-based separation, mostly for hydrocarbon mixtures. Interestingly, being structurally close to silicalite-1, adsorption studies using silicalite-2 are scarce and to the best of our knowledge, a comparative study of their behavior for alcohol-water mixtures has not been published to date. We have here resorted to molecular simulation techniques to analyze the adsorption and diffusion phenomena in both zeolites at 25 and 50 °C for pure methanol, ethanol, 1-butanol, and water, and for some relevant compositions of alcohol/water mixtures. In addition to the dilute regime in the mixture, our study ranges from intermediate alcohol concentrations to alcohol-rich phases, relevant to alcohol purification processes. Besides, we have performed volumetric and calorimetric measurements of single-component adsorption of alcohols in pure silica MEL zeolite, which were used to validate the model potentials used in the simulations. We observe that the zigzag channels of MFI zeolite are most likely responsible for its somewhat higher affinity for alcohols. This leads to higher adsorption selectivities when compared to those of MEL zeolite. We have also found that the choice of water model strongly conditions water coadsorption into the zeolites and subsequently the predictions of the adsorbent's selectivity in alcohol/water systems. Despite considerable differences for adsorbed pure components, diffusivities of alcohol and water adsorbed from mixtures are relatively similar, as a consequence of the strong hydrogen bonds between hydroxyl groups and water.

Polymeric Nanocomposites for Dehydration of Isopropyl Alcohol–Water Mixtures by Pervaporation

Polymeric Nanocomposites for Dehydration of Isopropyl Alcohol–Water Mixtures by Pervaporation

On the Use of a Twin Screw Extruder for Continuous Solid Feeding and Dissolution for Continuous Flow Processes

The progress from batch to continuous manufacture of pharmaceuticals has highlighted the challenging area of dosing solid material directly, efficiently, and accurately into continuous flow systems for workup in flow chemistry processes. Twin screw extruders (TSEs) have the advantage of decoupling the dry (loss in weight feeder end) from the wet (liquid input) to prevent solids from sticking around the feeder, thereby enabling continuous solid feeding into a flow process. In this study, the feasibility of a 16 mm TSE as a solid feeder is investigated, and efficient dissolution of an example active pharmaceutical ingredient (API) is demonstrated. Paracetamol and an 80:20 mixture of water and isopropyl alcohol are the solute and solvent, respectively. The concentrations of paracetamol during dissolution experiments are monitored using an in-line UV attenuated total reflectance probe connected to a spectrometer, and the dissolution kinetics is extracted. Full dissolution of powder particles is obtained withi...

Integrated digital holographic microscopy based on surface plasmon resonance.

We propose a novel digital holographic microscopy (DHM) by integrating surface plasmon holographic microscopy (SPHM) with reflection DHM based on the angular and polarization multiplexing techniques. Taking advantages of the high sensitivity of surface plasmon resonance (SPR) and the high reflectivity of gold film, the tiny variations of specimen's refractive index (RI) can be measured by using SPHM, and meanwhile, the thickness changes of the specimen can be determined by means of reflection DHM. We experimentally monitor the volatilization process of an alcohol-water mixture droplet to verify the validity of the integrated DHM. The proposed microscopy is very promising in the objective-coupling SPR microscopy for multi-information measurements of diverse specimens with low-contrast RI distributions (biomolecules, nanofluids, etc.) in a dynamic and nondestructive way.

Characteristic of aroma compounds recovery from binary and ternary (alcohol-ester-water) aqueous solutions with use of pervaporation

The aim of this study was to examine and quantitatively describe how the coupling phenomenon affects the pervaporation. In the first stage binary water-alcohol (ethanol; isopentanol) and water-ester (methyl butyrate; butyl acetate) mixtures were examined. In the second stage three different ternary water-ester-alcohol solutions have been separated with the use of commercially available PDMS (polydimethyl siloxane) membrane and the effect of separation was expressed with the semi-empirical Arrhenius-like equation and strictly empirical Response Surface Methodology (RSM). Modelling results show that the coupling phenomenon is very case-specific, and the addition of another species to the separated solution could have both a negative and positive impact on the productivity and separation efficiency, depending on the characteristic of penetrant-penetrant and membrane-penetrant interactions. The relationship between process parameters and coupling effects strongly affects pervaporation performance, and yields dissimilar results for various concentrations of feed components in multicomponent systems.

Studying the radioprotective properties of some phytoextracts from Azerbaijan pharmaceutical flora

Aim. The aim of this work is to evaluate the radioprotective properties of the extract from the flowers of calendula officinalis (Calendula officinalis L.) alone and phytoextracts (CDY) consisting of calendula officinalis (Calendula officinalis), dandelion officinalis (Taráxacum officinále) and yarrow (Achillea millefolium) obtained from medicinal flora of Azerbaijan. Methods. The medicinal plants included in the collection were dried and the extract obtained in a water-alcohol mixture. The extracts were injected intraperitoneally in mice at a concentration of 300 mg / kg 30 min before irradiation at a dose of 9 Gy. Results. It was found out that the extract of calendula possesses radioprotective activity (55%), somewhat inferior to the activity of the protector-standard of cystamine (80%), and phytoextracts (CDY) decreasing the lethal effect of ionizing radiation, has radioprotective activity (62%) and increases survival and life expectancy lethally irradiated mice more than the extract of calendula (55%) and less cystamine (80%). Conclusions. The data obtained by us testify to the prospects of using the extract of calendula separately and in a complex of extracts of dandelion and yarrow in the development of medicinal compositions intended for preventive purposes and in order to prevent local radiation injuries.
 Keywords: mice, survival, irradiation, extract, cystamine.

Performance comparison of Ni/TiO2 and Au/TiO2 photocatalysts for H2 production in different alcohol-water mixtures

This study systematically compares the performance of 0.5 wt% Ni/P25 TiO2 and 2 wt% Au/P25 TiO2 photocatalysts for H2 production in alcohol-water mixtures under UV excitation. HRTEM, XANES and EXAFS confirmed the presence of 5–8 nm Ni0 and Au0 nanoparticles on the surface of the photocatalysts. H2 production tests were conducted in various alcohol-water systems (0–100 vol%), using methanol, ethanol, ethylene glycol and glycerol. The Ni/P25 TiO2 and Au/P25 TiO2 photocatalysts demonstrated remarkably similar performance for hydrogen production in all the alcohol-water systems tested. At low alcohol concentrations (15 vol% or less), H2 production rates followed the order glycerol > ethylene glycol > methanol > ethanol, whilst at higher alcohol concentrations methanol (optimum 40 vol%) and ethanol (optimum 80–90 vol%) afforded the highest rates. Rates depended on the polarity and oxidation potential of the alcohol. Further, anatase-rutile heterojunctions in P25 TiO2 were found to greatly enhance H2 production.

A model for predicting flash point of alkane-alkane and water-alcohol mixtures by the Cubic-Plus-Association Equation of State

A vapor-pressure-based model has been constructed to predict the closed-cup flash points of binary miscible mixtures. The model utilizes a cubic-plus-association (CPA) equation of state (EoS) to thermodynamically describe the behavior of both liquid and vapor phases. The alkane-alkane and water-alcohol mixtures were selected to examine the predictive potential of the model. Compared to known models, which use the activity coefficient models, the proposed flash point calculation procedure has fewer binary interaction parameters (BIPs) and does not need the Antoine equation to calculate the vapor pressure of pure components. Moreover, another advantage is that by utilizing the published experimental flash point data, no binary vapor-liquid equilibrium (VLE) data are required to obtain the BIPs.

Highly reactive anatase nanorod photocatalysts synthesized by calcination of hydrogen titanate nanotubes: Effect of calcination conditions on photocatalytic performance for aqueous dye degradation and H2 production in alcohol-water mixtures

A series of anatase TiO2 nanorod photocatalysts, denoted herein as xTiO2(t) where x = calcination temperature and t = calcination time, were successfully synthesized by calcination of H2Ti3O7 nanotubes at 500–700 °C for 10–240 min. SEM, TEM, XRD and BET analyses demonstrated that nanorods with different aspect ratios, crystallite sizes and surface areas (15–93 m2 g−1) could be obtained by varying the calcination conditions. The 600TiO2(t) and 700TiO2(t) nanorods demonstrated superior photocatalytic activity to Degussa P25 TiO2 for methylene blue photo-oxidation at pH 6, and also superior activity for H2 production in alcohol-water systems following decoration with Pd, Au or Pd-Au co-catalysts. Under UV excitation (365 nm, 6.5 mW cm−2), Pd-Au/600TiO2(20) afforded H2 production rates of 37.2, 44.0 and 45.6 mmol g−1 h−1 in 10 vol.% ethanol-water, ethylene glycol-water and glycerol-water mixtures, respectively. Co-catalyst activity for the 600TiO2(t) and P25 TiO2 photocatalysts followed the order Pd-Au > Pd > Au.

A numerical study of buoyancy-Marangoni convection of volatile binary fluids in confined geometries

A horizontal temperature gradient can cause a flow in a layer of liquid with a free surface via several different mechanisms. The most universal one is due to thermocapillary stresses that arise due to the temperature dependence of surface tension. For binary liquids, the flow can also be driven by solutocapillary stresses that arise due to the dependence of surface tension on the composition of the liquid. For some binary liquids, such as water-alcohol mixtures, solutocapillary stresses are primarily due to phase change (e.g., differential evaporation or condensation of the two components), and these two mechanisms can counteract each other. A recent experimental study (Li and Yoda, 2016) has demonstrated that the flow direction can be reversed by changing the amount of air present inside the experimental apparatus. To understand how the presence of air affects the interfacial stresses, we have developed and implemented numerically a comprehensive two-sided transport model, which accounts for transport of heat, mass, and momentum in both phases and phase change across the interface and is able to reproduce the experimental results. The detailed analysis of these results shows that air tends to suppress phase change and hence solutocapillary stresses. Removing the air enhances phase change, instead suppressing the variation in the interfacial temperature and hence thermocapillary stresses.

CAVITATIONAL SYNTHESIS OF CARBON NANOFORMS BY WATER HAMMER

We consider features of the carbon composite nano-particles formation at cavitation by means of the hydro impact. The comparison of given method with existing methods of synthesis in nanotechnology was carried out. The crystal structure of the various carbon nanoforms synthesized by hydrodynamic cavitation in a mixture of water and isopropyl alcohol was investigated using the methods of electron diffraction. Such polymorphs of carbon as the nano-diamond, nanographite and composites were revealed. The lattices characteristics of the synthesized carbon nano forms were analyzed. Applications of results for microelectronics were considered.

Influence of molecular structure of alcohol-water mixtures on bubble behaviour and bubble surface mobility

The behaviour of spherical bubbles rising in water-ethanol and water-propanol mixtures was investigated experimentally for the whole range of concentrations, from pure water to pure alcohol. These two alcohols were chosen for their importance in industrial applications and for their peculiar properties resulting from the formation of organised microstructures in the non-ideal mixture at a molecular level. The effect of the composition of the alcohol-water mixtures on the physicochemical properties of the liquid was evaluated for all the solutions investigated, compared with literature values to critically access the effect of the concentration of alcohol on the bulk and interfacial properties of the mixtures. The hydrodynamic behaviour of bubbles rising in the mixtures was evaluated, by using high speed video to measure the bubble size and terminal velocity. From the corresponding drag coefficients, the mobility of the bubble’s surface was determined revealing that in alcohol-water mixtures there are three regions: (1) with very low alcohol concentrations (xE ≤ 0.01, xP ≤ 0.005), the solutions behave as surfactant solutions with increase of bubble’s drag coefficient with increase of the alcohol concentration till total immobilization of the bubble surface; (2) at intermedium concentration, the drag coefficient decreases as the concentration of alcohol increases with consequent increase of competition for location of alcohol molecules at the interface or on the bulk with formation of molecular network; (3) at high concentration (xE ≥ 0.20 and xP ≥ 0.07), the bubbles have again fully mobile surface as in a pure liquid.