scholarly journals Viscosity Measurements of Dilute Poly(2-ethyl-2-oxazoline) Aqueous Solutions Near Theta Temperature Analyzed within the Joint Rouse-Zimm Model

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jana Tóthová ◽  
Katarína Paulovičová ◽  
Vladimír Lisý
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Aqueous Solutions ◽  
Intrinsic Viscosity ◽  
Shear Viscosity ◽  
Hydrodynamic Interaction ◽  
Arrhenius Equation ◽  
Polymer Dynamics ◽  
Usual Assumption ◽  
Theta Temperature

The steady-state shear viscosity of low-concentrated Poly(2-ethyl-2-oxazoline) (PEOX) aqueous solutions is measured near the presumed theta temperature using the falling ball viscometry technique. The experimental data are analyzed within the model that joins the Rouse and Zimm bead-spring theories of the polymer dynamics at the theta condition, which means that the polymer coils are considered to be partially permeable to the solvent. The polymer characteristics thus depend on the draining parameterhthat is related to the strength of the hydrodynamic interaction between the polymer segments. The Huggins coefficient was found to be 0.418 at the temperature 20°C, as predicted by the theory. This value corresponds toh= 2.92, contrary to the usual assumption of the infiniteh. This result indicates that the theta temperature for the PEOX water solutions is 20°C rather than 25°C in the previous studies. The experimental intrinsic viscosity is well described coming from the Arrhenius equation for the shear viscosity.

scholarly journals Study of the effect of temperature on the electrical conductivity of aqueous solutions of amino acids

2019 ◽  
Vol 57 (1) ◽  
pp. 91-94
Author(s):  
Vera A. Petrukhina ◽  
◽  
Pavel I. Fedorov ◽  
Tatiana A. Kirillova ◽  
Ludmila Yu. Tcareva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Amino Acids ◽  
Electrical Conductivity ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Arrhenius Equation ◽  
Effect Of Temperature ◽  
Acid Solutions ◽  
Hydrogen Ions ◽  
Amino Acid Solutions

It is well-known fact that water is a universal solvent due to its physicochemical properties and dielectric constant. Therefore, the majority of substances with a crystalline structure and the structure close to it are well soluble in water due to the dissociation of molecules into ions. Amino acids are organic ampholytes – substances capable of being in ionic forms in water. The quantitative and qualitative composition of ampholytes depends on the structure and composition of amino acids and pH of solution. The interaction of amino acid ions in solution with hydrogen ions and hydroxyl leads to the formation of complex cations and anions. The presence of amino and carboxyl groups in amino acid molecules contributes to the formation of inter-ion positively and negatively charged complexes which leads to the decrease in their mobility and electrical conductivity of solutions. It is observed with increasing concentration of amino acid solutions. The conductivity of amino acid solutions is also influenced by temperature which has a non-linear relationship. We have proposed the approach based on studying the effect of temperature on the equivalent electrical conductivity at infinite dilution λ∞ and describing the experimental data λ∞(Т) by the exponential Arrhenius equation. This article studies the possibility of describing the experimental data λ∞(Т) for aqueous solutions of a number of amino acids by this equation. It is shown that the Arrhenius equation with the found activation energy values adequately describes the dependences of limiting equivalent conductivity on temperature for aqueous solutions of valine, leucine, isoleucine, threonine, lysine, methionine, phenylalanine, L-aspartic and D-aspartic acids, histidine, arginine.

Kinetic analysis of mechanism of intestinal Na+-dependent sugar transport

1985 ◽  
Vol 248 (5) ◽  
pp. C498-C509 ◽  
Author(s):  
D. Restrepo ◽  
G. A. Kimmich
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Sugar Transport ◽  
Enzyme Kinetic ◽  
Steady State Distribution ◽  
State Distribution ◽  
Least Squares Fit ◽  
Coupling Stoichiometry ◽  
Rate Limiting ◽  
Kinetics Of

Zero-trans kinetics of Na+-sugar cotransport were investigated. Sugar influx was measured at various sodium and sugar concentrations in K+-loaded cells treated with rotenone and valinomycin. Sugar influx follows Michaelis-Menten kinetics as a function of sugar concentration but not as a function of Na+ concentration. Nine models with 1:1 or 2:1 sodium:sugar stoichiometry were considered. The flux equations for these models were solved assuming steady-state distribution of carrier forms and that translocation across the membrane is rate limiting. Classical enzyme kinetic methods and a least-squares fit of flux equations to the experimental data were used to assess the fit of the different models. Four models can be discarded on this basis. Of the remaining models, we discard two on the basis of the trans sodium dependence and the coupling stoichiometry [G. A. Kimmich and J. Randles, Am. J. Physiol. 247 (Cell Physiol. 16): C74-C82, 1984]. The remaining models are terter ordered mechanisms with sodium debinding first at the trans side. If transfer across the membrane is rate limiting, the binding order can be determined to be sodium:sugar:sodium.

scholarly journals Experimental data on the removal of acid orange 10 dye from aqueous solutions using TiO2/Na-Y zeolite and BiVO4/Na-Y zeolite nanostructures: A comparison study

Data in Brief ◽  
2021 ◽  
Vol 35 ◽  
pp. 106869
Author(s):  
Behzad Rahimi ◽  
Nayereh Rezaie-Rahimi ◽  
Negar Jafari ◽  
Ali Abdolahnejad ◽  
Afshin Ebrahimi
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Comparison Study ◽  
Y Zeolite ◽  
Acid Orange ◽  
Acid Orange 10

Diffusion Coefficients of Interest for the Simulation of Heat Treatment in Rare-Earth Transition Metal Magnets

2012 ◽  
Vol 727-728 ◽  
pp. 163-168 ◽  
Author(s):  
Marcos Flavio de Campos
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Activation Energy ◽  
Rare Earth ◽  
Transition Metal ◽  
Impurity Atom ◽  
Diffusion Coefficients ◽  
Arrhenius Equation ◽  
Atom Diffusion ◽  
Essential Input

In the case of the modeling of sintering and heat treatments, the diffusion coefficients are an essential input. However, experimental data in the literature about diffusion coefficients for rare-earth transition metal intermetallics is scarce. In this study, the available data concerning diffusion coefficients relevant for rare-earth transition metal magnets are reviewed and commented. Some empirical rules are discussed, for example the activation energy is affected by the size of the diffusing impurity atom. Diffusion coefficients for Dy, Nd and Fe into Nd2Fe14B are given according an Arrhenius equation D=D0exp (-Q/RT). For Dy diffusion into Nd2Fe14B, Q 315 kJ/mol and D08 . 10-4m2/s.

Electron drift caused by rf field gradient creates many plasma phenomena: An attempt to distinguish the cause and the effect

2011 ◽  
Vol 78 (2) ◽  
pp. 165-174 ◽  
Author(s):  
C. L. XAPLANTERIS ◽  
E. D. FILIPPAKI ◽  
I. S. MISTAKIDIS ◽  
L. C. XAPLANTERIS
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Low Temperature ◽  
Mathematical Models ◽  
Field Gradient ◽  
Collision Frequency ◽  
The Other ◽  
Frequency Effect ◽  
Electron Drift ◽  
Plasma Parameters

AbstractMany experimental data along with their theoretical interpretations on the rf low-temperature cylindrical plasma have been issued until today. Our Laboratory has contributed to that research by publishing results and interpretative mathematical models. With the present paper, two issues are being examined; firstly, the estimation of electron drift caused by the rf field gradient, which is the initial reason for the plasma behaviour, and secondly, many new experimental results, especially the electron-neutral collision frequency effect on the other plasma parameters and quantities. Up till now, only the plasma steady state was taken into consideration when a theoretical elaboration was carried out, regardless of the cause and the effect. This indicates the plasma's complicated and chaotic configuration and the need to simplify the problem. In the present work, a classification about the causality of the phenomena is attempted; the rf field gradient electron drift is proved to be the initial cause.

Detection Limit of Large Area Id Thin Film Position Sensitive Detectors Based in a-Si:H P.I.N. Diodes

1995 ◽  
Vol 377 ◽  
Author(s):  
R. Martins ◽  
G. Lavareda ◽  
F. Soares ◽  
E. Fortunato
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Steady State ◽  
Detection Limit ◽  
Large Area ◽  
Position Sensitive ◽  
Position Sensitive Detectors

ABSTRACTThe aim of this work is to provide the basis for the interpretation of the steady state lateral photoeffect observed in p-i-n a-Si:H ID Thin Film Position Sensitive Detectors (ID TFPSD). The experimental data recorded in ID TFPSD devices with different performances are compared with the predicted curves and the obtained correlation's discussed.

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