Preference for Isolated Water Molecules in a Concentrated Glycerol–Water Mixture

2011 ◽  
Vol 115 (24) ◽  
pp. 7799-7807 ◽  
Author(s):  
J. J. Towey ◽  
A. K. Soper ◽  
L. Dougan
Keyword(s):  
Water Molecules ◽  
Water Mixture ◽  
Glycerol Water

The Thermal and Rheological Properties of Starch Plasticized in Glycerol-Water Mixture

2011 ◽  
Vol 343-344 ◽  
pp. 38-42 ◽  
Author(s):  
Peng Liu ◽  
Cai Qin Gu ◽  
Qing Zhu Zeng
Keyword(s):  
Phase Transition ◽  
Rheological Properties ◽  
Water Molecules ◽  
Water Mixture ◽  
Time Curve ◽  
Lipid Complex ◽  
Glycerol Water ◽  
Rich Mixture ◽  
Plasticization Effect ◽  
Dsc Curves

The interaction between glycerol and water molecules is very complex, which displays different plasticization properties. In this paper, it studied the influence of glycerol-water mixture with different glycerol ratio on the thermal and rheological properties of starch. In water-rich mixture (glycerol ratio is less than 50%), its plasticization effect is similar as water, but will be impaired with the increase of glycerol. In glycerol-rich mixture (glycerol ratio is more than 90%), its lubrication and plasticization effect is similar as glycerol, and since glycerol can abstract lipid and destroy amylose-lipid complex, the peak M2 disappeared in DSC curves. In transition mixture, the mutual interactions reach maximal and less active hydroxy left, so the plasticization effect is the weakest, which is reflected by the highest loading peak and phase transition peak in torque-time curve by rheometer.

HYDROTHERMAL SYNTHESIS OF CALCIUM HYDROSILICATES

1934 ◽  
Vol 11 (4) ◽  
pp. 520-529 ◽  
Author(s):  
V. A. Vigfusson ◽  
G. N. Bates ◽  
T. Thorvaldson
Keyword(s):  
Hydrothermal Synthesis ◽  
Silica Gel ◽  
Fused Silica ◽  
Steam Treatment ◽  
Crystalline Substance ◽  
Water Mixture ◽  
Glycerol Water ◽  
X Ray ◽  
Lime Water ◽  
Calcium Hydrosilicate

A crystalline substance which appears in steam-cured Portland cement mortar has been shown to be a calcium hydrosilicate and has been prepared by hydrothermal synthesis from mixtures of silica sand with lime, dicalcium silicate and tricalcium silicate, silica gel and lime (after preliminary steam treatment and ignition) and by the action of saturated lime water on quartz crystals or fused silica plates. The crystals appear not to be acted on by solutions of sodium sulphate, calcium sulphate or alkali hydroxides, but they are slowly decomposed by solutions of magnesium sulphate and alkali carbonates and rapidly by dilute acids and ammonium salts. The crystals were obtained free from amorphous matter by growing them on quartz or silica plates in saturated lime water. When the compound was prepared in this way, the lime-silica-water ratio was found to be 2:1:1, the formula being therefore 2CaO∙SiO2∙H2O or H2Ca2SiO5. This product usually appears as thin lath-like prisms showing parallel extinction, positive elongation and moderate birefringence. The crystals are optically positive with a fairly large optic angle. 2V = 68°. The indices of refraction are αNa = 1.614 ±.002, βNa = 1.620 ±.002, γNa = 1.633 ±.002. The optical plane is parallel to the macropinacoid (100) and the acute bisectrix Z is parallel to the direction of elongation which is taken as the crystallographic axis C. The optical properties and X-ray pattern are distinctive and entirely different from those of hillebrandite or foshagite, which have the same composition.Another crystalline calcium hydrosilicate was obtained by hydrothermal synthesis from excess lime and silica gel. This appeared as very small needle-like prisms, observable only when magnified about 200 times. The crystals show parallel extinction, positive elongation and very low birefringence with an index of refraction of 1.597 ±.003. Analysis of this product, extracted with a glycerol-water mixture to remove excess lime, gave a lime-silica ratio of 2 to 1 with an uncertain amount of water of at least one mole. The X-ray pattern is distinctive and shows only slight similarity to the hillebrandite pattern.

Experimental and CFD Investigations of Heat Transfer in Helical Coils for the Development of Correlations for Newtonian and Non-Newtonian Fluids in Transient State-Space Conditions

2013 ◽  
Author(s):  
Sandipan S. Pawar ◽  
Vivek K. Sunnapwar ◽  
Vivek K. Yakkundi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Flow Regimes ◽  
Newtonian Fluids ◽  
Water Mixture ◽  
Glycerol Water ◽  
Laminar And Turbulent Flow ◽  
Helical Coils

Experimental studies and CFD investigations were carried out under laminar and turbulent flow regimes in isothermal steady state and non-isothermal unsteady state conditions in helical coils for Newtonian and non-Newtonian fluids. Water and glycerol-water mixture (10 and 20 % glycerol) as Newtonian fluids and dilute aqueous polymer solutions of sodium carboxymethyl cellulose (SCMC), sodium alginate (SA) as non-Newtonian fluids were used in this study. The experiments were performed for three helical coils of coil curvature ratios as 0.0757, 0.064 and 0.055 in laminar and turbulent flow regimes. For the first time, two innovative correlations to calculate Nusselt number (Nu) in terms of new dimensionless ‘M’ number, Prandtl number and coil curvature ratio under different conditions for Newtonian fluids are proposed in this paper. Third correlation of Nu vs. Graetz number (Gz) including the effects of coil curvature on heat transfer coefficient which was not considered by earlier investigators is developed based on tests conducted in laminar flow for Newtonian fluids. All these three innovative correlations developed based on experimental data which were not found in the literature. These correlations were compared with the work of earlier investigators and were found to be in good agreement. The CFD analysis for laminar and turbulent flow was carried out using the CFD package FLUENT 12.0.16. The CFD calculation results (Nui, U) for laminar and turbulent flows were compared with the experimental results, and also the work of earlier investigators was found to be in excellent agreement. Further, the effect of helix diameter on heat transfer for Newtonian and Non-Newtonian fluids are also presented in this paper and it was observed that as helix diameter increases, overall heat transfer coefficient decreases.

MOLECULAR DYNAMICS SIMULATION ON THE STRUCTURE AND DYNAMICS OF WATER IN THE 1-BUTYL-3-METHYLIMIDAZOLIUM TETRAFLUOROBORATE/WATER MIXTURE

2010 ◽  
Vol 09 (03) ◽  
pp. 573-584 ◽  
Author(s):  
GUOCAI TIAN ◽  
JIAN LI
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Pure Water ◽  
Molar Fraction ◽  
Blue Shift ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Water Mixture ◽  
Structure And Dynamics ◽  
Hydrogen Bond Interactions

The micro-structure, and IR spectrum of water molecules in 1-butyl-3-methylimi- dazolium tetrafluoroborate( [Bmim]BF4 )/water mixture with different concentrations (x1 = 25.0%, 50.0%, 75.0%, and 90.0%) were studied with molecular dynamics simulation at room temperature. It was shown that water molecules tend to be isolated from each other in mixtures with more ions than water molecules in pure water. With the increase of the molar fraction of water in the mixture, the rotation bands and the bending bands of water display red shift from 566.2 to 651.4 cm-1 and from 1638.4 to 1683.2 cm-1 respectively, whereas the O–H stretch bands show blue shift from 3519.8 to 3452 cm-1, which agree well with the experimental results. This suggests that the molecules are hindered and their motions are difficult and slow, due to the hydrogen-bond interactions and the inharmonic interactions between the inter- or intra-molecular modes of water molecules.

scholarly journals The FMO Complex in a Glycerol–Water Mixture

2013 ◽  
Vol 117 (24) ◽  
pp. 7157-7163 ◽  
Author(s):  
Mortaza Aghtar ◽  
Johan Strümpfer ◽  
Carsten Olbrich ◽  
Klaus Schulten ◽  
Ulrich Kleinekathöfer
Keyword(s):  
Water Mixture ◽  
Glycerol Water

scholarly journals Influence of bubble content on laser-induced cavitation bubble oscillation in glycerol-water mixture

2009 ◽  
Vol 58 (12) ◽  
pp. 8400
Author(s):  
Zhao Rui ◽  
Xu Rong-Qing ◽  
Liang Zhong-Cheng ◽  
Lu Jian ◽  
Ni Xiao-Wu
Keyword(s):  
Cavitation Bubble ◽  
Water Mixture ◽  
Glycerol Water ◽  
Bubble Oscillation

Interactions of Glycerol, Diglycerol, and Water Studied Using Attenuated Total Reflection Infrared Spectroscopy

2020 ◽  
Vol 74 (7) ◽  
pp. 767-779 ◽  
Author(s):  
Akari Habuka ◽  
Takeshi Yamada ◽  
Satoru Nakashima
Keyword(s):  
Infrared Spectroscopy ◽  
Pure Water ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Outer Side ◽  
Water Molecules ◽  
Glycerol Water ◽  
Oh Groups ◽  
Water Solutions ◽  
Band Area

In order to examine the mixing properties of glycerol–water and diglycerol–water solutions, these solutions were measured using attenuated total reflection infrared spectroscopy. The absorbance spectra corrected for 1 µm thickness were subtracted by pure polyols for obtaining water spectra, and by pure water for polyol spectra. Both asymmetric and symmetric CH2 stretching vibration bands (around 2940, 2885 cm−1) shifted about 10 cm−1 to lower wavenumber side (redshifts) with increasing polyol concentrations, especially at higher concentrations. Redshifts of C–O–H rocking bands (around 1335 cm−1) with increasing polyol concentrations are slightly larger for diglycerol–water (10 > 6 cm−1) than glycerol–water solutions. C–O stretching bands of CHOH groups (1125 and 1112 cm−1) shift slightly but in opposite sides for glycerol and diglycerol at highest polyol concentrations (90–100 wt%). These shifts of CH2 stretching, COH rocking, and CO stretching of CHOH at higher polyol concentrations suggest interactions of outer CH2 with inner CHOH groups of surrounding polyols. The normalized band area changes with polyol concentrations could be fitted by quadratic polynomials possibly due to mixtures of different interactions between water–water, polyol–water, and polyol–polyol molecules. The OH stretching band for diglycerol 90 wt% shows three humps indicating at least three OH components: long, medium, and short H bond water molecules. Short H bond water molecules are the major component possibly between inner CHOH and outer side CH2OH groups, while the long H component might loosely bind to outer CH2OH groups.

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