Ultrasonic Speed and Thermodynamic Parameters of Novel Epoxy Resin Solutions Based on Cardo Symmetric Double Schiff Bases at 308.15 K

2012 ◽  
Vol 41 (5) ◽  
pp. 755-765 ◽  
Author(s):  
U. G. Pathak ◽  
J. V. Patel ◽  
P. H. Parsania
Author(s):  
B.J. Gangani ◽  
Parsotam H. Parsania

The density, viscosity and ultrasonic speed (2MHz) of chloroform and symmetric double Schiff bases have been investigated at 308.15K. Various acoustical parameters such as specific acoustical impedance (Z), adiabatic compressibility (Кa), Rao’s molarsound function (Rm), Vander Waals constant (b), internal pressure (π), free volume (Vf), intermolecular free path length (Lf), classical absorption coefficient (α/f2)Cl) and viscous relaxation time (τ) were determined using ultrasonic speed (U), viscosity (η) and density (ρ) data of Schiff bases solutions and correlated with concentration. Increasing linear or nonlinear trends of (Z, Rm, b, τ and (α/f2)Cl) and decreasing trend of Кa, Lf,, π and Vf with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions and solvophilic nature of the Schiff bases, which is further supported by the positive values of solvation number. The nature and position of substituent also affected the strength of molecular interactions.


Author(s):  
Bhavesh J. Gangani ◽  
Parsotam H. Parsania

The density (ρ), viscosity (η) and ultrasonic speed (U) (2MHz) of THF solutions of symmetric double Schiff bases (SDSB-1,SDSB-2 and SDSB-3) were determined at 303.15, 308.15 and 313.15 K. Various acoustical parameters such as specific acoustical impedance (Z), isentropic compressibility (ks), Rao’s molar sound function (Rm), Van der Waals constant (b), internal pressure (π), free volume (Vf), intermolecular free path length (Lf), viscous relaxation time (τ) and classical absorption coefficient (α/f2)Cl), were determined using ρ, η and U data. The results are interpreted in terms of molecular interactions occurring in the solutions at different temperatures and concentrations. Linear increase of ρ, η U, Z, Rm, b, (α/f2)Cl and τ with increasing C, linear decrease of КS, Lf and π with increasing T, Vf increased linearly with C and T except SDSB-3 supported existence of strong molecular interactions in the solutions and confirming solvophilic nature of the Schiff bases. The structure, nature and size of the solutes and solvent, concentration and temperature affected molecular interactions.


1979 ◽  
Vol 44 ◽  
pp. 349-355
Author(s):  
R.W. Milkey

The focus of discussion in Working Group 3 was on the Thermodynamic Properties as determined spectroscopically, including the observational techniques and the theoretical modeling of physical processes responsible for the emission spectrum. Recent advances in observational techniques and theoretical concepts make this discussion particularly timely. It is wise to remember that the determination of thermodynamic parameters is not an end in itself and that these are interesting chiefly for what they can tell us about the energetics and mass transport in prominences.


Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.


Author(s):  
J. Temple Black ◽  
William G. Boldosser

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.


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