Novel experimental liquid−liquid equilibrium measurements were performed for three ternary systems containing γ-valerolactone + n-tetradecane + (butanoic acid or hexanoic acid or methyl myristate) at T = 298.15 K. The quantification of the coexisting phases was performed using an indirect method which relies on the variation of physical properties (density) along the binodal curve. The experimental data were successfully correlated by the nonrandom two-liquid and the universal quasichemical models.
Although petroleum is widely used to make solvents and
energy, solvents derived from it, such as acetonitrile, may not be
the safest and most sustainable options currently available. Additionally,
processes such as the Fischer–Tropsch synthesis emerge as an
intelligent alternative to produce energy from coal, biomass, or natural
gas to supply the increasing demand for petroleum-derived products.
Thus, with a green solvent, γ-valerolactone, applied to the
removal of oxygenated compounds from a Fischer–Tropsch process
stream, this work suggests the application of a less toxic solvent
to an alternative energy production process through model systems.
In this sense, liquid–liquid equilibrium experimental data
were measured for systems composed of an oxygenated solute (1-heptanol,
propanone, 2-butanone, or 2-heptanone) + γ-valerolactone + n-tetradecane at 298.15 K. The liquid–liquid equilibrium
data were successfully correlated by the nonrandom two-liquid model
with a medium average deviation lower than 1%. Therefore, the measured
experimental data may contribute to the design of a liquid–liquid
extraction process applied to the refinement of synthetic crude oil
from a Fischer–Tropsch synthesis.
A compilation of available experimental data for acetone-water mixtures with the reciprocal salt system Na+, K+ || Cl−, SO42− is presented. Significant inconsistencies among experimental data are pointed out. New freezing point measurements are reported for the binary acetone-water system at 12 different compositions. UNIQUAC parameters are determined on the basis of the available data from literature. Modeling results are presented. Vapor-liquid, liquid-liquid, and solid-liquid equilibria together with thermal properties are reproduced well by the model using only 14 parameters. The major drawback of the model is that the calculated liquid-liquid equilibrium regions of systems with KCl and NaCl are larger than the experimentally determined regions. The model is valid in the temperature range from −16 to 100 °C.
No presente trabalho, a variável pH foi analisada para verificar a capacidade de adsorver íons de Pb(II) quando a casca de coco (Cocos nucifera L.) é totalmente seca e peneirada. Os resultados foram obtidos por meio de análises no equipamento de Espectroscopia de Absorção Atômica por chama (FAAS). O pó de casca de coco seco exibiu um resultado mais satisfatório (98,89%) em uma dose de 1000 mg L -1.
Solid−liquid equilibrium (SLE) data were obtained at 0.1 MPa for binary, ternary, and quaternary aqueous solutions containing ammonia (NH 3 ), ammonium bicarbonate (NH 4 HCO 3 ), methyl diethanolamine (MDEA), and potassium carbonate (K 2 CO 3 ) using a modified Beckmann apparatus. The reproducibility of the experimental method was verified by measuring the SLE of aqueous solutions containing NH 3 , K 2 CO 3 , or MDEA in a temperature range between 237 and 273 K. A total of 120 new data points were measured for MDEA−NH 3 and NH 4 HCO 3 −H 2 O mixtures (250 to 305 K), and 23 new data points were obtained for MDEA−K 2 CO 3 −H 2 O solutions (250 to 270 K). These measurements allow for an accurate estimation of water activity in such mixtures and provide insights on the limits of solid formation. The results indicate that the addition of MDEA increases the solubility of NH 4 HCO 3 , whereas a liquid−liquid split was observed when K 2 CO 3 was added to aqueous MDEA. This opens the possibility of using it as a phase demixing solvent for carbon capture. Despite the extensive literature regarding mixed salt−amine solutions, liquid demixing in such systems has not been reported before. For this reason, the binodal curve for the MDEA−K 2 CO 3 −H 2 O solution was measured at 293.15 K using the method of cloud point titration. These results assist the selection of operation parameters that avoid a liquid−liquid split in the process.
The evolution of dementia is strongly related to cognitive, motor, and functional changes and to the presence of cardiovascular diseases. Disturbances vary according to phase of dementia and can limit instrumental and basic activities of daily living. The aim of this study was to analyze the immediate physiological effects of listening to music before physical exercise in institutionalized older people with moderate to advanced dementia. A randomized trial was conducted with 18 institutionalized older people with dementia (mean age was 79 years old, 52.6% were female), who were divided into a Training with Music Group (TWMG) and a Training without Music Group (TWtMG). The evaluation included heart rate (HR), blood pressure (BP) and HR variability (HRV). The assessment was conducted in a closed environment or in places with minimal visual and auditory stimulation. The TWMG was submitted to stimuli with music for 15 minutes and physical exercises for 30 minutes to improve/maintain their global mobility. The TWtMG performed the same physical exercises, however without music before physical exercise. The interventions lasted 12 weeks, and were performed individually once a week. In the TWMG, we observe a decrease in diastolic BP in the third session. In the sixth week, the HR increased after the session in both groups. TWMG improved HRV in the third session, with a difference between groups only after the session. After the sixth session, HRV values improved in both groups. In conclusion, listening to music before physical exercise is associated with positive effects in people with dementia, as it tends to maintain and improve physiological factors.
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