Cross diffusion governs an oscillatory instability in a ternary mixture with the Soret effect.

In a ternary mixture with the Soret effect, the interplay between cross-diffusion, thermodiffusion, and convection can lead to rich and complex dynamics including spatial patterns and oscillations. We present an experimental and three-dimensional numerical study of dynamic regimes in the toluene-methanol-cyclohexane ternary mixture with the Soret effect in the geometry of a thermogravitational column. An important feature of the system is that for the first component, toluene, the Soret and thermodiffusion coefficients have opposite signs, which triggers the oscillatory instability.

Design and 3D printing of an electrochemical sensor for detection based on loop mediated isothermal amplification.

The aim of this work is the design and 3D printing of a new electrochemical sensor for the detection of based on loop mediated isothermal amplification (LAMP). The food related diseases involve a serious health issue all over the world. is one of the major problems of contaminated food, this pathogen causes a disease called listeriosis with a high rate of hospitalization and mortality.

Soret vector for description of multicomponent mixtures.

The Soret effect describes the transport of constituent species in multicomponent mixtures that occurs due to a temperature gradient. This cross-coupling effect of heat and mass transfer has been successfully examined in binary liquid mixtures, while experiments with ternary mixtures are rare as they impose significant difficulties. We introduce a new and innovative concept, the Soret vector, for the characterization of Soret driven separation in ternary mixtures.

High magnetization FeCo nanoparticles for magnetorheological fluids with enhanced response.

We present results concerning the fabrication of a new magnetorheological fluid with FeCo magnetic nanoparticles (NPs) as magnetic fillers. These NPs have been fabricated by using the chemical reduction technique and show a pure crystalline phase with size ranging among 30-50 nm and high magnetization, 212 ± 2 A m kg. They agglomerate due to the strong magnetic dipolar interaction among them.

On the thermodiffusion effect in vertical plate heat exchangers.

The subject of the transport phenomena has a pivotal role in the performance of aqueous lithium bromide falling film absorbers. Although the thermodiffusion phenomenon appears inside the solution, very little is known about its influence on the mass transport. This study numerically analyses the influence of the thermal mass transfer mechanism on a vertical plate-type heat exchanger for different Reynolds numbers ([Formula: see text]).

Separation under thermogravitational effects in binary mixtures.

In the present work, by using a parallelepipedic thermogravitational microcolumn, the temperature gradient influence on the stability of the flow has been examined, emphasizing mixtures with positive Soret coefficients. Experiments were conducted for DCMIX2 Toluene/Methanol and DCMIX3 Water/Ethanol binary subsystems because of their broad range of positive Soret values for high concentrations of methanol and ethanol, respectively. Two different mixtures have been studied here in order to confirm the thermogravitational stability of the mixtures.

Thermodiffusion in multicomponent -alkane mixtures.

Compositional grading within a mixture has a strong impact on the evaluation of the pre-exploitation distribution of hydrocarbons in underground layers and sediments. Thermodiffusion, which leads to a partial diffusive separation of species in a mixture due to the geothermal gradient, is thought to play an important role in determining the distribution of species in a reservoir. However, despite recent progress, thermodiffusion is still difficult to measure and model in multicomponent mixtures.

Soret coefficient of the n-dodecane-n-hexane binary mixture under high pressure.

In the present work, the Soret coefficient has been determined at high pressure for a binary hydrocarbon mixture by combining the thermogravitational column and the dynamic near-field imaging techniques. The analyzed mixture is an iso-massic n -dodecane-n -hexane mixture at 298.15K.

Thermodiffusion, molecular diffusion and Soret coefficients of aromatic+n-alkane binary mixtures.

In the present work, we have measured the thermodiffusion coefficient of 51 binary liquid mixtures at 25 C. These mixtures correspond to the series of the aromatics toluene and 1-methylnaphthalene with n-alkanes nCi (i = 6, 8, 10, 12, and 14) at different mass fractions in the whole range. For that, we have used the thermogravitational technique.

Soret coefficients of the ternary mixture 1,2,3,4-tetrahydronaphthalene + isobutylbenzene + n-dodecane.

In this work, the transport coefficients of the ternary mixtures of the diffusion coefficient measurements in ternary mixtures 1 project were determined. The analyzed ternary mixtures are formed by 1,2,3,4-tetrahydronaphthalene, isobutylbenzene, and dodecane (nC12) at different compositions. In all cases, the analysis was carried out at 25 °C.

Contribution to the benchmark for ternary mixtures: Determination of Soret coefficients by the thermogravitational and the sliding symmetric tubes techniques.

This work is part of an international project for the research on the transport properties in ternary mixtures. Six different teams have analysed the same mixture by independent techniques in order to compare the results and validate the techniques. This work is the contribution of the team of Mondragon Unibertsitatea for ground conditions measurements.

Thermodiffusion, molecular diffusion and Soret coefficient of binary and ternary mixtures of n-hexane, n-dodecane and toluene.

In this study, the thermodiffusion, molecular diffusion, and Soret coefficients of 12 binary mixtures composed of toluene, n-hexane and n-dodecane in the whole range of concentrations at atmospheric pressure and temperatures of 298.15 K and 308.15 K have been determined.

Mass effect on the Soret coefficient in n-alkane mixtures.

We have determined the Soret coefficient of different equimolar and non equimolar n-alkane mixtures from measurements of the molecular diffusion and thermal diffusion coefficients. It is shown that equimolar mixtures behave as isotopic-like mixtures in which only the mass effect contributes to the Soret effect. In non equimolar mixtures, a small linear dependence with the molar fraction is observed.

Determination of the molecular diffusion coefficients in ternary mixtures by the sliding symmetric tubes technique.

A new analytical methodology has been developed to determine the diagonal and cross-diagonal molecular diffusion coefficients in ternary mixtures by the Sliding Symmetric Tubes technique. The analytical solution is tested in binary mixtures obtaining good agreement with the results of the literature. Results are presented for the ternary mixture formed by tetralin, isobutylbenzene, and dodecane with an equal mass fraction for all the components (1-1-1) which is held at 25 °C.

Development of a thermogravitational microcolumn with an interferometric contactless detection system.

We present a new type of thermogravitational (TG) column, a so-called TG microcolumn with transparent windows and a very small sample volume of less than 50 μL. The TG microcolumn has a planar geometry with a thickness of 0.523 ± 0.

Determination of molecular diffusion coefficient in n-alkane binary mixtures: empirical correlations.

In this work we have measured the molecular diffusion coefficient of the n-alkane binary series nC(i)-nC(6), nC(i)-nC(10), and nC(i)-nC(12) at 298 K and 1 atm and a mass fraction of 0.5 by using the so-called sliding symmetric tubes technique. The results show that the diffusion coefficient at this concentration is proportional to the inverse viscosity of the mixture.

Measurement of thermodiffusion coefficient in n-alkane binary mixtures: composition dependence.

In this work, we have measured the thermodiffusion coefficient of different n-alkane binary mixtures at several concentrations using the thermogravitational technique. In particular, we have studied the n-dodecane/n-heptane system as a function of composition and other systems covering a large range of mass differences and concentration at 25 degrees C and 1 atm. The results show that for any concentration the thermodiffusion coefficient of n-alkane mixtures is proportional to the mass difference between the components and to the ratio of the thermal expansion coefficient and viscosity of the mixture.

Thermodiffusion coefficients of binary and ternary hydrocarbon mixtures.

In this study, we have measured the thermodiffusion coefficients of six hydrocarbon liquid ternary mixtures at 25 degrees C using the thermogravitational technique. Mixtures of 1,2,3,4-tetrahydronaphthalene-isobutylbenzene-n-dodecane at four different concentrations and 1,2,3,4-tetrahydronaphthalene-isobutylbenzene-n-decane at two concentrations have been considered. We have used a plane-thermogravitational column with a small gap dimension to improve the accuracy of the recently reported data.

Determination of thermal diffusion coefficient in equimolar n-alkane mixtures: Empirical correlations.

In this article we determined the thermal diffusion coefficient (D(T)) in equimolar mixtures of n-alkanes nC(i)-nC(12) (i=5,6,7,8,9,17,18), nC(i)-nC(10) (i=5,6,7,15,16,17,18), and nC(i)-nC(6) (i=10,12,14,16,18) at 25 degrees C and at atmospheric pressure using the thermogravitational technique. The results obtained from this study together with the previously published ones in the series of nC(i)-nC(18) (i=5,6,7,8,9,10,11,12,13) show that the main parameter that determines D(T) in each series is in association with the molecular weights of the mixture's components. However, an empirical quantitative correlation has been obtained between D(T), the molecular weights of the components, the viscosity, and the thermal expansion coefficient of the mixtures.

An improved theoretical model for thermal diffusion coefficient in liquid hydrocarbon mixtures: Comparison between experimental and numerical results.

Thermal diffusion or Soret effect is a phenomenon of mass transport in fluid mixtures driven by temperature gradients. In this paper, we have studied thermal diffusion coefficients for different binary n-alkane mixtures (equal mass fraction) through both theoretical and experimental methods. The theoretical model is based on the irreversible thermodynamics.

Thermal diffusion and molecular diffusion values for some alkane mixtures: a comparison between thermogravitational column and thermal diffusion forced rayleigh scattering.

In the present work we studied the thermal diffusion behavior of n-decane in various alkanes by thermogravitational column (TC) technique and the thermal diffusion forced Rayleigh scattering (TDFRS) method. The investigated lighter alkanes compared to n-decane are n-pentane, n-hexane, n-heptane, n-octane, and the heavier ones are n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and n-eicosane. The binary mixture n-decane/ n-pentane we investigated at several different concentrations; all other mixtures were only investigated at a mass fraction of 50%.

Measurements of molecular and thermal diffusion coefficients in ternary mixtures.

Thermal diffusion coefficients in three ternary mixtures are measured in a thermogravitational column. One of the mixtures consists of one normal alkane and two aromatics (dodecane-isobutylbenzene-tetrahydronaphthalene), and the other two consist of two normal alkanes and one aromatic (octane-decane-1-methylnaphthalene). This is the first report of measured thermal diffusion coefficients (for all species) of a ternary nonelectrolyte mixture in literature.