scholarly journals Determination of critical micelle concentration of cetyltrimethylammonium bromide: Different procedures for analysis of experimental data

2016 ◽  
Vol 70 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Jelena Goronja ◽  
Aleksandra Janosevic-Lezaic ◽  
Biljana Dimitrijevic ◽  
Andjelija Malenovic ◽  
Dragomir Stanisavljev ◽  
...  
Keyword(s):  
Critical Micelle Concentration ◽  
Cetyltrimethylammonium Bromide ◽  
Integration Method ◽  
Water Mixture ◽  
Micellar System ◽  
Sharp Transition ◽  
Water Conductivity ◽  
Micellar Systems ◽  
Significant Difference

Conductivity of two micellar systems was measured in order to determine critical micelle concentration (CMC) of cetyltrimethylammonium bromide (CTAB). Those systems were: CTin water and CTin binary mixture acetonitrile (ACN)-water. Conductivity (?)-concentration (c) data were treated by four different methods: conventional method, differential methods (first and second derivative) and method of integration (methods A-D, respectively). As CTin water micellar system shows a sharp transition between premicellar and postmicellar part of the ?/c curve, any of the applied methods gives reliable CMC values and there is no statistically significant difference between them. However, for CTin ACN-water mixture micellar system the integration method for CMC determination is recommended due to a weak curvature of ?/c plot.

Interaction of sulphone based reactive dyes with cationic surfactant: a spectroscopic and conductometric study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Misbah Iram ◽  
Hamadia Sultana ◽  
Muhammad Usman ◽  
Bazgha Ahmad ◽  
Nadia Akram ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Cetyltrimethylammonium Bromide ◽  
Hydrophobic Interactions ◽  
Reactive Dyes ◽  
Micellar System ◽  
Palisade Layer ◽  
Micellar Systems ◽  
Gibbs Energies ◽  
Electrostatic And Hydrophobic Interactions ◽  
Conductometric Study

Abstract Interaction of sulphone based reactive dyes, designated as dye-1 and dye-2, with cationic micellar system of cetyltrimethylammonium bromide (CTAB), has been investigated by spectroscopic and conductometeric measurements. Efficiency of the selected micellar systems is assessed by the values of binding constant (K b ), partition coefficient (K x ) and respective Gibbs energies. Critical micelle concentration (CMC) of surfactant, electrostatic and hydrophobic interactions as well as polarity of the medium plays significant role in this phenomenon. The negative values of Gibbs energies of binding (∆G b ) and partition (∆G p ) predicts the feasibility and spontaneity of respective processes. Similarly negative values of ∆G m and ∆H m and positive values of ∆S m , calculated from conductometeric data, further, revealed the exothermicity, spontaneity and, thus, stability of system. The results, herein, have disclosed the strong interaction between dye and surfactant molecules. The dye-2 has been observed to be solubilized to greater extent, as compared to dye 1, due to strong interaction ith hydrophiles of CTAB and accommodation of its molecules in palisade layer of micelle closer to the micelle/water interface.

Determination of frost hardiness of Eucalyptus using the electrical conductivity of diffusate in conjunction with a freezing chamber

1988 ◽  
Vol 18 (5) ◽  
pp. 595-600 ◽  
Author(s):  
P. M. Hallam ◽  
W. N. Tibbits
Keyword(s):  
Electrical Conductivity ◽  
Frost Hardiness ◽  
Lethal Temperature ◽  
Conductivity Method ◽  
Water Conductivity ◽  
Leaf Discs ◽  
Significant Difference ◽  
Maximum Conductivity ◽  
Electrical Conductivity Method

An electrical conductivity method for determining frost hardiness of tissue discs punched from Eucalyptus leaves is described. Samples were exposed to convective heat loss in an air-filled chamber. Rates of cooling and desired frost temperatures were electronically controlled and maintained. Supercooling of tissue was effectively eliminated by addition of small amounts of AgI and water. Conductivity of diffusate was measured as a means of quantifying tissue damage following frost. Relative conductivity was determined with reference to subsequent measurements following heating the discs to 70 °C which resulted in maximum conductivity. Exposure of leaf discs to temperatures below the lethal temperature for these species (<−10 °C) resulted in similar maximum conductivity readings. The technique is evaluated to assess its potential to distinguish small differences in frost hardiness caused by genotype and environment. For both E. delegatensis and E. nitens there was no significant difference in frost hardiness expressed in terms of mean lethal temperature when comparing leaf discs with frosting whole seedlings.

scholarly journals Determination of critical micelle concentration of cetyltrimethylammonium bromide in presence and absence of KCl and NaCl in aqueous media at room temperature by viscosity measurement

BIBECHANA ◽  
2014 ◽  
Vol 11 ◽  
pp. 131-135 ◽  
Author(s):  
Kabita Jha ◽  
Ajaya Bhattarai ◽  
Sujeet Kumar Chatterjee
Keyword(s):  
Ionic Strength ◽  
Critical Micelle Concentration ◽  
Sharp Increase ◽  
Cetyltrimethylammonium Bromide ◽  
Room Temperature ◽  
Aqueous Media ◽  
Viscosity Measurement ◽  
Reference List ◽  
Versus Concentration

NOTE: The correct reference list was added to this article on 08/07/2014.Viscosity measurement of cetyltrimethylammonium bromide in presence and in absence of KCl and NaCl in aqueous media is done. The results showed a sharp increase in viscosity with increase in concentration of cetyltrimethylammonium bromide. Also, the viscosity increases with addition of salts. The viscosity of cetyltrimethylammonium bromide is found more in presence of KCl than NaCl in aqueous media. In presence of monovalent salts, the critical micelle concentration (cmc) value decreases which is explained on the basis of nature and ionic strength of the added ion. The graphs of viscosity versus concentration are used in determining the critical micelle concentration (cmc). DOI: http://dx.doi.org/10.3126/bibechana.v11i0.10392BIBECHANA 11(1) (2014) 131-135

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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