scholarly journals Ultrasonic Investigation on Hydroxy Ethyl Propyl Cellulose (HEPC) Solution at Different Concentration and pH

2020 ◽  
Vol 32 (9) ◽  
pp. 2255-2261
Author(s):  
S. ARUNA ◽  
R. THIYAGARAJAN ◽  
A. PANNEERSELVAM
Keyword(s):  
Absorption Coefficient ◽  
Aqueous Solutions ◽  
Conformational Changes ◽  
Chemical Nature ◽  
Propagation Characteristics ◽  
Physico Chemical ◽  
Different Temperatures ◽  
Ultrasonic Techniques ◽  
Ultrasonic Parameters ◽  
Ultrasonic Investigation

The ultrasonic investigation is one of the most effective and economical technique to analyze the nature of the matter. Ultrasonic techniques provide valuable information about the physico-chemical nature of the aqueous solutions. Thus, the propagation characteristics of an acoustical wave in solutions are used to study the nature of intermolecular interaction. In this work, the ultrasonic velocity, viscosity and density studies were determined to study the effect of concentration and pH in the aqueous hydroxyethyl propyl cellulose (HEPC) solutions at different temperatures (303, 313 and 323 K). From the observed values, the necessary related ultrasonic parameters are calculated and their variations are discussed. The findings from the result say the variations in the velocity and absorption coefficient values are only due to the conformational changes that occur in the HEPC solution.

scholarly journals III. On the relations between the viscosity (internal friction) of liquids and their chemical nature.—Part II

1897 ◽  
Vol 189 ◽  
pp. 71-107 ◽  
Keyword(s):  
Chemical Composition ◽  
Chemical Nature ◽  
Carbonyl Oxygen ◽  
Organic Substances ◽  
A Value ◽  
Physico Chemical ◽  
Chemical Constitution ◽  
Ether Oxygen ◽  
Different Temperatures ◽  
Additional Reason

In the Bakerian Lecture for 1894 (‘Phil. Trans.,’ vol. 185 A, p. 397), we gave an account of our work on the viscosity of some seventy liquids at different temperatures between 0° and the ordinary boiling-point, and we discussed the interdependence of viscosity and chemical composition. Among the liquids dealt with on that occasion, there was no member of the important series of esters or ethereal salts, and, further, only one ether—ordinary ether or ethyl oxide—was included in the list. We therefore thought it desirable, in order to make the investigation more complete, to obtain data for members of these two classes of organic substances. The physico-chemical relationships previously established made such determinations of particular interest. Among the various connections traced between chemical constitution and viscosity, one of the most striking was the different effect which oxygen exerted upon viscosity according to the different modes in which it was assumed to be associated with other atoms in the molecule. The influence which could be ascribed to hydroxyl-oxygen differs to a most marked extent from that of carbonyl-oxygen, and, although only three cases were studied, it appeared that ether oxygen, or oxygen linked to two carbon atoms, had also a value which differed considerably from those of oxygen in other conditions. There was thus an additional reason for making observations on esters and ethers, since both contain ether-oxygen.

Study of polymer chain dynamics in solution by time-resolved spectrofluorometry

1989 ◽  
Vol 54 (11) ◽  
pp. 3011-3024 ◽  
Author(s):  
Vlastimil Fidler ◽  
Stefan Vajda ◽  
Zuzana Limpouchová ◽  
Jiří Dvořák ◽  
Karel Procházka ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Conformational Changes ◽  
Methacrylic Acid ◽  
Correlation Time ◽  
General Level ◽  
Polymeric Chain ◽  
Relative Molecular Mass ◽  
Chain Dynamics ◽  
Time Resolved ◽  
Covalently Bonded

The methodology of polarization time-resolved fluorometry and interpretation of its results are outlined at a general level, and the measurement on and use of facilities of the Edinburgh Instruments Model 299T apparatus are discussed in detail. The dynamics of conformational changes in chains of poly(methacrylic acid) containing covalently bonded dansyl labels are studied in aqueous solutions at various pH. It is shown that at pH > 6, the shorter effective rational correlation time τr < 2 ns corresponds to the rotation of the free dansyl label about bonds by which it is attached to the polymeric chain; at pH < 4 the longer effective rational correlation time τr = 20-26 ns corresponds to the rotation of the compact spherical formation constituted by a part of the collapsed polymeric chain in which the label is fixed and whose relative molecular mass is approx. 15 000-20 000.

scholarly journals Impact of Deuteration and Temperature on Furan Ring Dynamics

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2889
Author(s):  
Przemyslaw Dopieralski ◽  
Iryna V. Omelchenko ◽  
Zdzislaw Latajka
Keyword(s):  
Conformational Changes ◽  
Furan Ring ◽  
Computational Studies ◽  
Significant Progress ◽  
Dynamic Simulations ◽  
Cyclic Molecules ◽  
Ring Dynamics ◽  
Different Temperatures ◽  
Long Time ◽  
Shape And Size

Despite significant progress in conformational analysis of cyclic molecules, the number of computational studies is still limited while most of that available in the literature data have been obtained long time ago with outdated methods. In present research, we have studied temperature driven conformational changes of the furan ring at three different temperatures. Additionally, the effect of deuteration on the ring dynamics is discussed; in addition, the aromaticity indices following the Bird and HOMA schemes are computed along all trajectories. Our ab initio molecular dynamic simulations revealed that deuteration has changed the furan ring dynamics and the obvious consequences; in addition, the shape and size of molecule are expected to be different.

Kinetics and thermodynamics of the sorption of furaltadone from aqueous solutions on magnetic multi-walled carbon nanotubes

2014 ◽  
Vol 70 (6) ◽  
pp. 964-971
Author(s):  
Xu Chen ◽  
Zhen-hu Xiong
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Sorption Data ◽  
Multi Wall Carbon Nanotubes ◽  
Adsorption Behaviors ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Pseudo Second Order ◽  
Experimental Data Analysis ◽  
Walled Carbon Nanotubes

Magnetic multi-wall carbon nanotubes (M-MWCNTs) were used as an adsorbent for removal of furaltadone from aqueous solutions, and the adsorption behaviors were investigated by varying pH, sorbent amount, sorption time and temperature. The results showed that the adsorption efficiency of furaltadone reached 97% when the dosage of M-MWCNT was 0.45 g · L−1, the pH was 7 and the adsorption time was 150 min. The kinetic data showed that the pseudo-second-order model can fit the adsorption kinetics. The sorption data could be well explained by the Langmuir model under different temperatures. The adsorption process was influenced by both intraparticle diffusion and external mass transfer. The experimental data analysis indicated that the electrostatic attraction and π–π stacking interactions between M-MWCNT and furaltadone might be the adsorption mechanism. Thermodynamic analysis reflected that adsorption of furaltadone on the M-MWCNT was spontaneous and exothermic. Our study showed that M-MWCNTs can be used as a potential adsorbent for removal of furaltadone from water and wastewater.

Physico-chemical study of aqueous solutions of electrolytes in mixed solvents

2006 ◽  
Vol 38 (11) ◽  
pp. 1474-1478 ◽  
Author(s):  
Monimul Huque ◽  
Iqbal Ahmed Siddiquey ◽  
Md. Nizam Uddin
Keyword(s):  
Aqueous Solutions ◽  
Mixed Solvents ◽  
Chemical Study ◽  
Physico Chemical ◽  
Solutions Of Electrolytes

Physico-Chemical Nature of Bacteriolysis

Nature ◽  
1944 ◽  
Vol 153 (3875) ◽  
pp. 169-170 ◽  
Author(s):  
W. A. DORFMAN
Keyword(s):  
Chemical Nature ◽  
Physico Chemical

Study the Effect of Heat Treatment and Pressure on some the Optical Properties of the Pure PVA Nano Polymer

2021 ◽  
Vol 900 ◽  
pp. 16-25
Author(s):  
Tabarak Mohammed Awad ◽  
May A.S. Mohammed
Keyword(s):  
Heat Treatment ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Polyvinyl Alcohol ◽  
Complex Dielectric Constant ◽  
Different Temperatures ◽  
German Origin ◽  
Increasing Temperature

In this study, some optical properties were studied of the pure vinyl polyvinyl alcohol (PVA) nanopolymer (German origin). Under the influence of different temperatures and pressures of PVA. Where 25 samples were prepared for the purpose of conducting the research. Which studied the study of these samples was done by recording the absorbance and transmittance spectra of the wavelengths (200-900) nm. From them, absorbance, transmittance, reflectivity, absorption coefficient, refractive index, extinction coefficient, complex dielectric constant were calculated. At different temperatures (25,40, 80, 120, 160)°C. And with different pressures within the range (7.5,8,8.5,9,9.5) MPa. The results are that the permeability of the polymer (PVA) at different temperatures for each pressure decreases with increasing temperature, and that all other calculated optical properties increase with increasing temperature.

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