Coupled diffusion of butanol solubilized in aqueous sodium dodecylsulfate micelles

1990 ◽  
Vol 68 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Derek G. Leaist
Keyword(s):  
Pure Water ◽  
Sodium Dodecylsulfate ◽  
Restricted Diffusion ◽  
Solution Viscosity ◽  
Diffusion Method ◽  
Coupled Flow ◽  
Aqueous Sodium ◽  
Coupled Diffusion ◽  
Interdiffusion Coefficients

Ternary interdiffusion coefficients have been measured for ten compositions of the system sodium dodecylsulfate (NaDS) + 1-butanol (BuOH) + water at 25 °C. The diffusivity of BuOH in this system is lower than in pure water because about one half of the alcohol is solubilized in the slowly-diffusing NaDS micelles. Yet, surprisingly, diffusion of the NaDS component transports only minor amounts of BuOH. Diffusion of the BuOH component, however, produces a substantial coupled flow of NaDS. Although added BuOH increases the solution viscosity and the size of the micelles, the diffusivity of the NaDS component does not change significantly. The Harned restricted diffusion method for the determination of electrolyte diffusivities is extended to electrolyte + nonelectrolyte solutes. Keywords: micelles, ionic; solubilization; diffusion, coupled.

Moments analysis of restricted ternary diffusion: sodium sulfite + sodium hydroxide + water

1985 ◽  
Vol 63 (11) ◽  
pp. 2933-2939 ◽  
Author(s):  
Derek G. Leaist
Keyword(s):  
Sulfur Dioxide ◽  
Sodium Hydroxide ◽  
Diffusion Coefficients ◽  
Sodium Sulfite ◽  
Pure Water ◽  
Alkaline Solutions ◽  
Coupled Flow ◽  
Ternary Diffusion ◽  
Aqueous Sodium ◽  
Ternary Diffusion Coefficients

Ternary diffusion coefficients can be determined from restricted-diffusion experiments by evaluating zeroth and first time moments of the difference in a concentration-dependent property measured at two levels along the diffusion column. The method is used to determine ternary diffusion coefficients for aqueous sodium sulfite + sodium hydroxide solutions from conductance measurements. It is shown that these data can be analyzed to obtain the ternary diffusivity of sulfur dioxide in strongly alkaline solutions where sulfite is the major transporting species for the sulfur dioxide component. At high pH values, coupled flow of hydroxide ions leads to a significant increase in the diffusivity of the sulfur dioxide component relative to its diffusivity in pure water. Binary diffusion coefficients for aqueous sodium sulfite solutions are also reported.

scholarly journals ANTIMICROBIAL AND ANTIOXIDANT EFFECT OF NATURAL EXTRACTS FROM LEAVES, ROOT, STEM AND FLOWERS OF BACCHARIS LATIFOLIA FROM ECUADOR

2020 ◽  
pp. 78-84
Author(s):  
FAVIAN BAYAS-MOREJON ◽  
ANGELICA TIGRE ◽  
RIVELINO RAMON ◽  
DANILO YANEZ
Keyword(s):  
Antimicrobial Activity ◽  
Antioxidant Activity ◽  
Potassium Phosphate ◽  
Natural Antioxidants ◽  
Butylated Hydroxytoluene ◽  
Penicillin G ◽  
Diffusion Method ◽  
E Coli ◽  
Antibacterial And Antioxidant Activity

Objective: The increase in chronic and degenerative diseases and the use of synthetic antioxidants such as (butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT)) are being restricted because they can be considered carcinogenic. Therefore, there is a growing interest in the search for natural antioxidants, especially from plants, due to their content in different bioactive compounds, such as antioxidants and antimicrobials. To evaluate the antibacterial and antioxidant activity of Baccharislatifolia extracts. Methods: For the determination of the antimicrobial activity of extracts of leaves, root, stem and flowers of Baccharislatifolia (Bl), the disk plate diffusion method was used, the strains of Listeria, Salmonella and E. coli were studied; antibiotics Penicillin G and Ciprofloxacin were the controls. For the antioxidant activity, a solution of H2O2 (Abs at 230 nm) was prepared in Potassium Phosphate Monobasic-Sodium Hydroxide buffer. Results: The antimicrobial activity against Listeria and Salmonella, showed that the extracts of leaves and flowers were more effective with inhibition zones>15 mm and>20 mm respectively. In front of E. coli, the extracts of flowers and stem were the best with zones>7.0 mm. Antibiotics studied inhibited the development of Listeria and Salmonella. However, E. coli isolates were resistant. In the antioxidant activity, the flower extract of Bl in 60 mg/ml presents a higher effect with 47.25%. Conclusion: Bl extracts from leaves and flowers were more efficient both in their antimicrobial and antioxidant capacity.

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

1960 ◽  
Vol 38 (9) ◽  
pp. 1488-1494 ◽  
Author(s):  
E. J. Bounsall ◽  
W. A. E. McBryde
Keyword(s):  
Aqueous Solution ◽  
Nitric Acid ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Silver Content ◽  
Aqueous Sodium Chloride Solution ◽  
Aqueous Sodium

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

scholarly journals Phytochemical screening and in vitro antibacterial, antifungal, antioxidant and antitumor activities of the red propolis Alagoas

2019 ◽  
Vol 79 (3) ◽  
pp. 452-459 ◽  
Author(s):  
F. R. G. Silva ◽  
T. M. S. Matias ◽  
L. I. O. Souza ◽  
T. J. Matos-Rocha ◽  
S. A. Fonseca ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Gallic Acid ◽  
Bioactive Metabolites ◽  
Diffusion Method ◽  
Total Phenolic ◽  
Phytochemical Screening ◽  
Dpph Method

Abstract The study aimed to evaluate the antimicrobial activity, antioxidant, toxicity and phytochemical screening of the Red Propolis Alagoas. Antimicrobial activity was evaluated by disk diffusion method. Determination of antioxidant activity was performed using the DPPH assay (1.1-diphenyl-2-picrylhydrazyl), FTC (ferric thiocyanate) and determination of phenolic compounds by Follin method. Toxicity was performed by the method of Artemia salina and cytotoxicity by MTT method. The phytochemical screening for the detection of allelochemicals was performed. The ethanol extract of propolis of Alagoas showed significant results for antimicrobial activity, and inhibitory activity for Staphylococcus aureus and Candida krusei. The antioxidant activity of the FTC method was 80% to 108.3% hydrogen peroxide kidnapping, the DPPH method showed an EC50 3.97 mg/mL, the content of total phenolic compounds was determined by calibration curve gallic acid, resulting from 0.0005 mg/100 g of gallic acid equivalent. The extract was non-toxic by A. salina method. The propolis extract showed high activity with a higher percentage than 75% inhibition of tumor cells OVCAR-8, SF-295 and HCT116. Chemical constituents were observed as flavonones, xanthones, flavonols, and Chalcones Auronas, Catechins and leucoanthocyanidins. It is concluded that the extract can be tested is considered a potential source of bioactive metabolites.

Effect of viscoelasticity on the soft-wall transition and turbulence in a microchannel

2017 ◽  
Vol 812 ◽  
pp. 1076-1118 ◽  
Author(s):  
S. S. Srinivas ◽  
V. Kumaran
Keyword(s):  
Molecular Weight ◽  
Reynolds Number ◽  
Reynolds Stress ◽  
Mass Fraction ◽  
Rectangular Cross Section ◽  
Pure Water ◽  
Polymer Concentration ◽  
Wall Turbulence ◽  
Solution Viscosity ◽  
Soft Wall

The modification of soft-wall turbulence in a microchannel due to small amounts of polymer dissolved in water is experimentally studied. The microchannels are of rectangular cross-section with height ${\sim}$160 $\unicode[STIX]{x03BC}\text{m}$, width ${\sim}$1.5 mm and length ${\sim}$3 cm, with three walls made of hard polydimethylsiloxane (PDMS) gel, and one wall made of soft PDMS gel with an elasticity modulus of ${\sim}$18 kPa. Solutions of polyacrylamide of molecular weight $5\times 10^{6}$ and mass fraction up to 50 ppm, and of molecular weight $4\times 10^{4}$ and mass fraction up to 1500 ppm, are used in the experiments. In all cases, the solutions are in the dilute limit below the critical overlap concentration, and the solution viscosity does not exceed that of water by more than 10 %. Two distinct types of flow modifications are observed below and above a threshold mass fraction for the polymer, $w_{t}$, which is ${\sim}$1 ppm and 500 ppm for the solutions of polyacrylamide with molecular weights $5\times 10^{6}$ and $4\times 10^{4}$, respectively. At or below $w_{t}$, there is no change in the transition Reynolds number, but there is significant turbulence attenuation, by up to a factor of 2 in the root-mean-square velocities and a factor of 4 in the Reynolds stress. When the polymer concentration increases beyond $w_{t}$, there is a decrease in the transition Reynolds number and in the intensity of the turbulent fluctuations. The lowest transition Reynolds number is ${\sim}$35 for the solution of polyacrylamide with molecular weight $5\times 10^{6}$ and mass fraction 50 ppm (in contrast to 260–290 for pure water). The fluctuating velocities in the streamwise and cross-stream directions are lower by a factor of 5, and the Reynolds stress is lower by a factor of 10, in comparison to pure water.

scholarly journals Essential Oil from Ocimum basilicum (Omani Basil): A Desert Crop

2011 ◽  
Vol 6 (10) ◽  
pp. 1934578X1100601 ◽  
Author(s):  
Ahmed Yahya Al-Maskri ◽  
Muhammad Asif Hanif ◽  
Masoud Yahya Al-Maskari ◽  
Alfie Susan Abraham ◽  
Jamal Nasser Al-sabahi ◽  
...  
Keyword(s):  
Essential Oil ◽  
Pathogenic Fungi ◽  
Essential Oil Composition ◽  
Ocimum Basilicum ◽  
Diffusion Method ◽  
Oil Composition ◽  
Different Seasons ◽  
Dpph Scavenging ◽  
Basil Oil

The focus of the present study was on the influence of season on yield, chemical composition, antioxidant and antifungal activities of Omani basil ( Ocimum basilicum) oil. The present study involved only one of the eight Omani basil varieties. The hydro-distilled essential oil yields were computed to be 0.1%, 0.3% and 0.1% in the winter, spring and summer seasons, respectively. The major components identified were L- linalool (26.5 - 56.3%), geraniol (12.1 - 16.5%), 1,8-cineole (2.5 - 15.1%), ρ-allylanisole (0.2 - 13.8%) and DL-limonene (0.2 -10.4%). A noteworthy extra component was β- farnesene, which was exclusively detected in the oil extracted during winter and spring at 6.3% and 5.8%, respectively. The essential oil composition over the different seasons was quite idiosyncratic, in which the principal components of one season were either trivial or totally absent in another. The essential oil extracted in spring exhibited the highest antioxidant activity (except DPPH scavenging ability) in comparison with the oils from other seasons. The basil oil was tested against pathogenic fungi viz. Aspergillus niger, A. fumigatus, Penicillium italicum and Rhizopus stolonifer using a disc diffusion method, and by determination of minimum inhibitory concentration. Surprisingly high antifungal values were found highlighting the potential of Omani basil as a preservative in the food and medical industries.

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