scholarly journals Investigations on the Effects of Salts and Carbohydrates on L-Lysine in Aqueous System at T=293.15K

2021 ◽  
Vol 37 (3) ◽  
pp. 704-709
Author(s):  
Rajesh Kumar Sharma ◽  
Priyanka Sharma
Keyword(s):  
Experimental Data ◽  
Amino Acids ◽  
Surface Tension ◽  
Sodium Chloride ◽  
Physicochemical Parameters ◽  
Aqueous System ◽  
Specific Conductance ◽  
Stabilization Mechanism ◽  
Solvent Interactions ◽  
Physicochemical Studies

Physicochemical studies of amino acids in an aqueous medium can provide significant knowledge about the stabilization mechanism of proteins.In this study, the viscosity (ƞ), surface tension (γ), density (ρ) and the specific conductance (κ) measurements have been carried out for amino acid L-lysine (0.02 to 1.6M) in aqueous solutions at 293.15K. The experimental data shows that there is an increase in the viscosity, surface tension, conductance, and density of the L-lysine with and without glucose, sucrose, sodium chloride, and potassium chloride with concentration.The solute-solute and solute-solvent interactions have been discussed on the basis of all physicochemical parameters.

Effects of Copper Extraction-Stripping Loops on Entrainment in Aqueous Raffinate

2014 ◽  
Vol 908 ◽  
pp. 18-21
Author(s):  
Yan Jun Liu ◽  
Xiao Rong Liu ◽  
Hui Li ◽  
Yong Sheng Li ◽  
Qing Li ◽  
...  
Keyword(s):  
Surface Tension ◽  
Solvent Extraction ◽  
Early Stage ◽  
Organic Chemical ◽  
Copper Extraction ◽  
Organic Chemicals ◽  
Stabilization Mechanism ◽  
Absolute Value ◽  
Copper Solvent Extraction ◽  
Average Size

Effects of extraction-stripping loops of organic phase on organic chemical entrainment in the aqueous raffinate in copper solvent extraction were studied in this paper. Results demonstrated that the total amount of organic chemicals lost in the aqueous raffinate decreased with the increase of times of extraction-stripping loops but reached largest at third loop. Entrainment was the dominate way of organic chemicals losing in the aqueous raffinate at early stage of the loops. The formation of entrainment and its stabilization mechanism was also studied. The average size of entrained droplet trended to increase with extraction-stripping loops increasing. Meanwhile, the absolute value of zeta potential trended to decrease. The surface tension of the aqueous raffinate increased after reaching the minimum value 41.3 mN/m at the 3rd loop. It showed that the formation of entrained droplets and its stability were mainly affected by the surface tension of aqueous raffinate.

scholarly journals Revisiting Kelvin equation and Peng–Robinson equation of state for accurate modeling of hydrocarbon phase behavior in nano capillaries

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ilyas Al-Kindi ◽  
Tayfun Babadagli
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Equation Of State ◽  
Phase Behavior ◽  
Pore Radius ◽  
Microfluidic Chips ◽  
Tight Sandstone ◽  
Kelvin Equation ◽  
Rock Samples ◽  
Robinson Equation

AbstractThe thermodynamics of fluids in confined (capillary) media is different from the bulk conditions due to the effects of the surface tension, wettability, and pore radius as described by the classical Kelvin equation. This study provides experimental data showing the deviation of propane vapour pressures in capillary media from the bulk conditions. Comparisons were also made with the vapour pressures calculated by the Peng–Robinson equation-of-state (PR-EOS). While the propane vapour pressures measured using synthetic capillary medium models (Hele–Shaw cells and microfluidic chips) were comparable with those measured at bulk conditions, the measured vapour pressures in the rock samples (sandstone, limestone, tight sandstone, and shale) were 15% (on average) less than those modelled by PR-EOS.

scholarly journals Multi-scale modeling of electronic spectra of three aromatic amino acids: importance of conformational averaging and explicit solute–solvent interactions

2014 ◽  
Vol 16 (38) ◽  
pp. 20639-20649 ◽  
Author(s):  
Petr Štěpánek ◽  
Petr Bouř
Keyword(s):  
Amino Acids ◽  
Quantum Mechanics ◽  
Molecular Mechanics ◽  
Electronic Spectra ◽  
Aromatic Amino Acids ◽  
Molecular Structures ◽  
Solvent Interactions ◽  
Multi Scale ◽  
Scale Modeling ◽  
Multi Scale Modeling

Electronic spectra provide a wealth of information on molecular structures. We demonstrate a very satisfactory agreement between experimental and modeled spectra, as obtained by combined molecular mechanics/quantum mechanics computations for three aromatic amino acids.

Technology of production and quality assessment of direct-squeezed juice and concentrated elderberry growing in the Republic of Belarus

2021 ◽  
pp. 83-87
Author(s):  
Леонид Чеславович Бурак ◽  
Андрей Петрович Завалей
Keyword(s):  
Amino Acids ◽  
Physicochemical Parameters ◽  
Mass Fraction ◽  
Essential Amino Acids ◽  
Quantitative Composition ◽  
Protein Mass ◽  
Juice Extraction ◽  
The Republic ◽  
First Time ◽  
Technology Of Production

Авторами статьи впервые разработана технология производства соков прямого отжима и высокой концентрации из плодов бузины садовой и дикорастущей, собранных на территории Беларуси. Сок прямого отжима получали при помощи ферментации с последующей фильтрацией. Концентрированный сок был получен из сока прямого отжима и экстрагирования выжимок. Для максимального извлечения сока после дробления при ферментативной обработке была использована температура 50 °С в течение 240 мин, количество ферментного препарата составляло 400 см/т. Были исследованы органолептические и физико-химические показатели сока прямого отжима и сока концентрированного: массовая доля сухих веществ, aктивная кислотность (рН), массовая доля пектиновых веществ, cодержание антоцианов, белка, массовая доля органических кислот. Исследованы показатели безопасности продукции, впервые определен состав аминокислот (качество и количество) в концентрированном соке бузины. Установлено, что совокупность физико-химических показателей позволяет отнести сок прямого отжима из бузины к профилактическим напиткам. В состав сока бузины высокой концентрации входят 18 аминокислот в количестве 4,84 г/100 мл. Незаменимых аминокислот выявлено 7 в количестве 1,51 г/100 мл. Также сок суммарно содержит фенолы в соотношении 42,95 мг-экв галловой кислоты/г сухого вещества и большое количество гидролизованных танинов. При этом большинство полифенольных соединений избежали разрушения в процессе концентрации. The authors of the article developed for the first time a technological process for the production of direct-squeezed juice and concentrated juice from the fruits of garden and wild elderberry growing in the Republic of Belarus. Direct-squeezed juice was obtained by fermentation followed by filtration. Concentrated juice was obtained by processing direct-squeezed juice and extracting the marc. For maximum juice extraction after crushing during enzymatic treatment, a temperature of 50 °C was used for 240 min, the dose of the enzyme preparation was 400 cm/t. Direct-squeezed juice and concentrated juice were studied by organoleptic and physicochemical parameters: mass fraction of solids, active acidity (pH), mass fraction of pectin substances, content of anthocyanins, protein, mass fraction of organic acids. The product safety indicators were studied, the qualitative and quantitative composition of amino acids in concentrated elderberry juice was first determined. It has been established that by the combination of physicochemical parameters, direct squeezed juice from elderberry can be considered a preventive drink. The composition of concentrated elderberry juice includes 18 amino acids, in the amount of 4.84 g/100 ml. 7 essential amino acids were detected in the amount of 1.51 g/100 ml. The concentrated juice contained phenols in the quantity of 42.95 mEq gallic acid / gram dry matter and a large number of hydrolyzed tannins. Most polyphenolic compounds were preserved after the juice concentration.

Concentration Dependence of the Surface Tension of Three and Four-Component Systems with Peculiarities in the Surface Tension Isotherms of Lateral Binary Melts

2021 ◽  
Vol 1022 ◽  
pp. 194-202
Author(s):  
R.Kh. Dadashev ◽  
R.A. Kutuev
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Concentration Dependence ◽  
Experimental Error ◽  
Binary Systems ◽  
Experimental Studies ◽  
Study Results ◽  
Component Systems ◽  
Minimum Depth ◽  
Surface Tension Isotherms

The experimental study results of the melts concentration dependence of the surface tension of the four-component indium-tin-lead-bismuth system and its constituent binary systems of indium-tin, indium-lead, indium-bismuth, tin-lead, tin-bismuth, lead-bismuth are presented in the paper. It is shown that the concentration dependence of the melts surface tension of the In-Sn-Pb-Bi four-component system can be predicted from the data on ST (surface tension) values of lateral binary systems. Features in the ST isotherms in the form of a minimum are observed only in the indium-tin lateral system from all lateral binaries. A distinctive feature of the detected minimum is that the minimum depth slightly exceeds the experimental error. Therefore, in addition to the fact that the area of average compositions was studied more thoroughly, we carried out the surface tension measurements by two independent methods. The experimental data obtained by both methods coincide within the experimental error and indicate the extremum availability on ST isotherms. Thus, ST experimental studies by two independent methods confirmed the presence of a flat minimum on ST isotherms of the indium-tin binary system increasing the reliability of the obtained data. The obtained outcomes and their comparison with experimental data have shown that the considered models for predicting surface properties based on data due to similar properties of lateral binary systems adequately reflect the experimental dependences. However, the prediction model based on Kohler's method of excess values describes the experimental curves more accurately.

scholarly journals Self-assembly of sodium dodecylsulfate and dodecyltrimethylammonium bromide mixed surfactants with dyes in aqueous mixtures

2019 ◽  
Vol 6 (3) ◽  
pp. 181979 ◽  
Author(s):  
K. M. Sachin ◽  
Sameer A. Karpe ◽  
Man Singh ◽  
Ajaya Bhattarai
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Sodium Dodecylsulfate ◽  
Critical Micellar Concentration ◽  
Aqueous System ◽  
Mixed Surfactants ◽  
Dodecyltrimethylammonium Bromide ◽  
Aqueous Mixtures ◽  
Krafft Temperature ◽  
Vis Spectroscopy

The micellar property of mixed surfactant systems, cationic (dodecyltrimethylammonium bromide, DTAB) and anionic (sodium dodecylsulfate, SDS) surfactants with variable molar ratios in aqueous system has been reported by using surface tension and conductivity measurements at T = 293.15, 298.15 and 303.15 K. DTAB concentrations are varied from 1.0 × 10 −4 to 3 × 10 −4 mol l −1 in 1.0 × 10 −2 mol l −1 SDS solution while the SDS concentration is varied from 1.0 × 10 −3 to 1.5 × 10 −2 mol l −1 in approximately 5.0 × 10 −3 mol l −1 DTAB, so that such concentrations of DTAB-SDS (DTAB-rich) and SDS-DTAB (SDS-rich) solutions were chosen 3 : 1 ratio. The critical micellar concentration, as well as surface and thermodynamic properties for DTAB-rich and SDS-rich solutions, were evaluated by the surface tension ( γ ) and conductivity ( κ ) methods. The pseudo phase separation model was coupled with the dissociated Margules model for synergism. The Krafft temperature behaviour and optical analysis of mixed surfactants are studied using conductivity and UV–Vis spectroscopy, respectively. The dispersibility and stability of DTAB-rich and SDS-rich solutions with and without dyes (2.5 × 10 −5 mol l −1 of methyl orange and methylene blue) are carried out by using UV–Vis spectroscopy and dynamic light scattering.

Numerical Simulation of Oil-Droplet Cleavage by Surfactant

1996 ◽  
Vol 118 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Xiaoyi He ◽  
Micah Dembo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Surface Tension ◽  
Large Deformation ◽  
Concentration Gradient ◽  
Surface Tension Gradient ◽  
Oil Droplets ◽  
Numerical Computations ◽  
Oil Droplet ◽  
Pure Surface

We present numerical computations of the deformation of an oil-droplet under the influence of a surface tension gradient generated by the surfactant released at the poles (the Greenspan experiment). We find this deformation to be very small under the pure surface tension gradient. To explain the large deformation of oil droplets observed in Greenspan’s experiments, we propose the existence of a phoretic force generated by the concentration gradient of the surfactant. We show that this hypothesis successfully explains the available experimental data and we propose some further tests.

scholarly journals INTERACTION STUDIES OF AMINO ACIDS IN AQUEOUS SODIUM BROMIDE SOLUTIONS AT DIFFERENT TEMPERATURE

2017 ◽  
Vol 5 (10) ◽  
pp. 160-167
Author(s):  
Yasmin Akhtar
Keyword(s):  
Amino Acids ◽  
Infinite Dilution ◽  
Adiabatic Compressibility ◽  
Sodium Bromide ◽  
Apparent Molal Volume ◽  
Partial Molal Volume ◽  
Molal Volume ◽  
Solvent Interactions ◽  
Aqueous Sodium ◽  
Bonding Effect

Densities, ultrasonic velocities and viscosities of L- Valine and L- Phenylalanine in aqueous sodium bromide (0.00, 0.025 and 0.05) m solutions have been determined experimentally at 308 and 313 K. The results obtained from density ultrasonic velocity and viscosity measurement have been used to calculate the apparent molal volume, фv, apparent molal, adiabatic compressibility ф Ks, partial molal volume ф0v at infinite dilution, partial molal adiabatic compressibility ф0Ks at infinite dilution, transfer volume ∆ф(tr), experimental slopes Sv and SKs,Falkenhagen coefficient A and  Jones-Dole B coefficient. The results are discussed in terms of the dehydration effect of the sodium bromide upon the amino acids and weak solute- solute and strong solute- solvent interactions. The properties of these amino acids in water and water + sodium bromide solution systems are discussed in terms of the charge, size and hydrogen bonding effect.

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