Temperature dependence of the shape of the cellodextrins in aqueous solution

1967 ◽  
Vol 45 (20) ◽  
pp. 2363-2367 ◽  
Author(s):  
M. Ihnat ◽  
D. A. I. Goring
Keyword(s):  
Aqueous Solution ◽  
Temperature Dependence ◽  
Computational Methods ◽  
Negative Temperature ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Increasing Temperature

Intrinsic viscosities of the cellodextrins, cellobiose to cellohexaose, were measured in aqueous solution at temperatures from 25 to 70 °C. Axial ratios were determined using the Einstein–Simha viscosity relation and the computational methods developed previously. The results showed that the oligomers are fully extended over this temperature range and that the negative temperature coefficients of the intrinsic viscosities are caused by the dehydration of the molecules with increasing temperature.

Temperature dependence of chlorine-35 N.Q.R. in 2,6-Dichlorophenol

1978 ◽  
Vol 31 (4) ◽  
pp. 791 ◽  
Author(s):  
R Chandramani ◽  
SP Basavaraju ◽  
N Devaraj
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Brown's Method

Chlorine n.q.r, in 2,6-dichlorophenol has been investigated at temperatures from 77 K to room temperature. Two resonance lines due to chemically inequivalent sites have been observed throughout this temperature range. Torsional frequencies of the molecule have been calculated at temperatures from 77 to 300 K according to Bayer's theory and Brown's method. Also the temperature coefficients of the torsional frequencies have been calculated.

NQR and Crystal Structure of 4,5-Dichloroimidazole, C3H2N2Cl2

1992 ◽  
Vol 47 (1-2) ◽  
pp. 177-181 ◽  
Author(s):  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Unit Cell ◽  
Space Group ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Group D

AbstractThe two line 35Cl NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77≦ T/K ≦ 389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v ( 35Cl)= f(T). Also the temperature coefficients of the 35Cl NQR frequencies are "normal". At 77 K the 35Cl NQR frequencies are 37.409 MHz and 36.172 MHz and at 389 K 35.758 MHz and 34.565 MHz. The compound crystallizes at room temperature with the tetragonal space group D44-P41212, Z = 8 molecules per unit cell; at 295 K : a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.

Thermal Anomaly in the Temperature Dependence of the Energy–Volume Coefficient of Aqueous KCl Solutions

1973 ◽  
Vol 51 (12) ◽  
pp. 1885-1888 ◽  
Author(s):  
Ikchoon Lee ◽  
J. B. Hyne
Keyword(s):  
Aqueous Solution ◽  
Temperature Dependence ◽  
Potassium Chloride ◽  
Direct Measurement ◽  
Pure Water ◽  
Pressure Coefficient ◽  
Thermal Anomaly ◽  
Thermal Pressure ◽  
Temperature Range ◽  
Volume Coefficient

The temperature dependence of the energy–volume coefficient of pure water and of aqueous potassium chloride solutions as a function of concentration over the temperature range 10–50 °C has been determined by direct measurement of constant volume thermal–pressure coefficient. The results show that a thermal anomaly exists in the energy–volume coefficient of aqueous solution in the temperature range 30–40 °C and becomes more pronounced as the concentration of solute is increased.

The flow of liquids with a temperature anomaly of viscosity

2003 ◽  
Vol 3 ◽  
pp. 232-245
Author(s):  
V.N. Kireev ◽  
S.F. Urmancheev
Keyword(s):  
Fluid Flow ◽  
Temperature Dependence ◽  
Temperature Anomaly ◽  
Numerical Study ◽  
Liquid Sulfur ◽  
Temperature Range ◽  
External Conditions ◽  
Increasing Temperature ◽  
Viscosity Dependence

For the vast majority of liquids, viscosity is a function that decreases monotonically with increasing temperature. However, a number of substances in which processes of polymerization and depolymerization can occur in a certain temperature range have a viscosity with a nonmonotonic temperature dependence. This dependence, for example, is characteristic of liquid sulfur. In this paper we present the results of a numerical study of the features of the flow of a liquid with a certain model nonmonotonic viscosity dependence on the temperature. The formation of a ”viscous barrier“ that determines the nature of the fluid flow in the channel is established. The main regularities of the flow are determined depending on the parameters of the viscous anomaly and external conditions.

The Temperature Dependence of the Electrical Conductivity Activation Energy of the of Aqueous Electrolyte Solutions

2021 ◽  
Vol 1031 ◽  
pp. 228-233
Author(s):  
Yuliya M. Artemkina ◽  
Vladimir V. Shcherbakov ◽  
Irina A. Akimova
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Temperature Dependence ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Temperature Step ◽  
Conductivity Activation Energy ◽  
Intermolecular Hydrogen Bonds ◽  
Optimal Value ◽  
Increasing Temperature

The procedure for determining the activation energy of conductivity Еκ is analyzed depending on the temperature step ΔT. It is shown that with increasing ΔT, the error in the calculation of Eκ decreases, but the calculated value of Eκ decreases. In order not to lose the temperature dependence of the activation energy, it is necessary to choose the optimal value of Δt. In our opinion, this value should not exceed 5 – 10 °C. Taking into account the decrease in concentration with increasing temperature due to a decrease in density has virtually no effect on the accuracy of determining Eκ, provided that ΔT is 5 – 10 °C. It has been shown that in the temperature range 20 – 80 °C, the activation energy of conductivity decreases with increasing temperature. This decrease is due to the rupture of intermolecular hydrogen bonds of the solvent with increasing temperature. It was suggested that the movement of ions in an aqueous solution may be accompanied by the breaking of hydrogen bond of the solvent.

Solubility of CO2 in an Aqueous Ammonium Based Ionic Liquid

2014 ◽  
Vol 625 ◽  
pp. 549-552 ◽  
Author(s):  
Rizwan Safdar ◽  
Abdul Aziz Omar ◽  
Lukman Ismail ◽  
Bhajan Lal
Keyword(s):  
Aqueous Solution ◽  
High Pressure ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ammonium Hydroxide ◽  
Loading Capacity ◽  
Temperature Range ◽  
Increasing Temperature

The aim of this research is to find out the potential usage of water miscible ammonium based ionic liquids (ILs) towards CO2capture. To measure the solubility of CO2in 55 wt. % aqueous solution of Tetra butyl ammonium hydroxide (TBAOH), the experiments were carried out using high pressure solubility cell. Solubilities were determined in the temperature range of (303.15 to 333.15) K by varying the pressure from (2 to 10) bar and are reported as loading capacity (mol CO2/mol TBAOH). The solubility of CO2in this aqueous IL decreased with increasing temperature and increased with increasing pressure.

g-Values for γ-irradiated water as a function of temperature

1990 ◽  
Vol 68 (5) ◽  
pp. 712-719 ◽  
Author(s):  
A. John Elliot ◽  
Monique P. Chenier ◽  
Denis C. Ouellette
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrated Electron ◽  
Temperature Range ◽  
Increasing Temperature

The g-values of primary species formed in the γ-radiolysis of water have been estimated for the temperature range 25–300 °C. The g-values for the hydrated electron, the hydroxyl radical, and molecular hydrogen all increase approximately 50% over this temperature range. The g-values for the minor products, hydrogen peroxide and atomic hydrogen, probably also increase with temperature; however, there is evidence from some of the experimental data which suggests that these g-values may slightly decrease with increasing temperature. Keywords: radiolysis, g-values, temperature dependence.

scholarly journals Simulation of Hydrogenated Amorphous Silicon: Temperature Dependence of Nonequilibrium Distribution Functions for Trap States

2021 ◽  
Author(s):  
Azuma Suzuki
Keyword(s):  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Negative Temperature ◽  
Distribution Functions ◽  
Trap States ◽  
Nonequilibrium Distribution ◽  
Increasing Temperature ◽  
P Type ◽  
Hydrogenated Amorphous

Abstract The nonequilibrium distribution functions (NDF) for the trap states in the mobility-gap under photo illumination and zero bias voltage are derived by the constructed self-consistent drift-diffusion simulator consisted of the Poisson equation and current continuity equations for hydrogenated amorphous silicon (a-Si:H). As for the temperature dependence of the NDF, we find that the values of the NDF decrease with increasing temperature (the negative temperature dependence) in the energy region near the conduction band for p-type a-Si:H. That is the reverse of the temperature dependence of the equilibrium distribution functions (EDF) for the trap states in the mobility-gap. Furthermore, we show that the new physical characteristic is applicable to the explanation of the temperature characteristic of the photoconductivity caused by the electron hopping in the conduction band tail for a-Si:H. The photoconductivity of a-Si:H decreases with increasing temperature, which is called the thermal quenching (TQ). We show that the TQ observed in a low temperature around 200K for p-type a-Si:H can be explained by the electron hopping model with the p-type NDF having the negative temperature dependence.

scholarly journals An estimate of the enthalpic contribution to the interaction between dextran and albumin

1978 ◽  
Vol 175 (2) ◽  
pp. 703-708 ◽  
Author(s):  
W D Comper ◽  
T C Laurent
Keyword(s):  
Aqueous Solution ◽  
Light Scattering ◽  
Temperature Dependence ◽  
Qualitative Agreement ◽  
Interaction Coefficient ◽  
Enthalpy Of Dilution ◽  
Scattering Data ◽  
Temperature Range ◽  
Considerable Error

It is demonstrated that exclusion phenomena appear to dominate the interaction of dextran with albumin in aqueous solution. The enthalpic contribution to the interaction coefficient describing dextran/albumin mixtures is small, although its determination was subject to considerable error. These results support the earlier assumptions of the type of interaction between the two polymers. The conclusions are primarily based on the interpretation of the temperature-dependence of the interaction coefficient, as measured by light-scattering in the temperature range 6–33 degrees C. Enthalpy of dilution measurements of dextran/albumin mixtures by microcalorimetry were in qualitative agreement with the light-scattering data.

scholarly journals WETTING ANGLE POLYTERMES FOR LEAD-SODIUM MELTS ON REFRACTORY METALS

2020 ◽  
pp. 113-119
Author(s):  
Барасби Сулейманович Карамурзов ◽  
Руслан Азаевич Кутуев ◽  
Мурат Хажисмелович Понежев ◽  
Виктор Адыгеевич Созаев ◽  
Астемир Хусенович Шерметов ◽  
...  
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Temperature Dependence ◽  
Refractory Metals ◽  
Wetting Angle ◽  
Temperature Range ◽  
Drop Method ◽  
Pure Helium ◽  
Increasing Temperature

Методом лежащей капли изучена температурная зависимость краевого угла смачивания сплавов Pb - Na разной концентрации на подложках из Co - Cr, Ni - Cr, нержавеющей стали 251892. Измерения проводились методом лежащей капли в широком интервале температур от 359°С до 800 °С в атмосфере чистого марки А. Показано, что значение угла смачивания уменьшается с увеличением температуры, наблюдаются пороги смачивания. The temperature dependence of the contact angle for Pb - Na melts of different concentrations on Co - Cr , Ni - Cr and stainless steel 25X18H9C2 substrate was studied by the method of a lying drop. Measurements were carried out by a lying drop method in the temperature range from 359 to 800 °C in an atmosphere of pure helium grade A. It is shown that the value of the wetting angle decreases with increasing temperature, wetting thresholds are observed.

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