scholarly journals Связь явлений переноса с характеристиками кластерной структуры воды

2019 ◽  
Vol 89 (6) ◽  
pp. 958
Author(s):  
А.В. Полянская ◽  
А.М. Полянский ◽  
В.А. Полянский
Keyword(s):  
Experimental Data ◽  
Binding Energy ◽  
Quantitative Data ◽  
Statistical Approach ◽  
Water Clusters ◽  
Free Water ◽  
Water Molecules ◽  
Superplastic State ◽  
Free Molecules ◽  
Density Of Water

AbstractUsing a statistical approach, we have estimated the size of water clusters and the number of free molecules participating in transport phenomena. The sizes of clusters and the number of molecules in them, as well as the number of free water molecules and their mean free paths, have been determined using experimental data on the temperature dependence of viscosity and density of water. It has been concluded that a temperature of 36.6°C is a special point in the range of 0–100°C. At temperatures higher than this value, the binding energy of a molecule with a cluster decreases abruptly, while the concentration of free molecules sharply increases. Quantitative data have been compared with the parameters of the superplastic state of titanium. As an example, we consider metabolism in functioning of erythrocytes of blood in an adult human.

Molecular Dynamics Study of Proton and Water Transport in Nafion Membrane

2013 ◽  
Author(s):  
Takuya Mabuchi ◽  
Takashi Tokumasu
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Water Clusters ◽  
Nafion Membrane ◽  
Water Molecules ◽  
Static Structure ◽  
Hydration Level ◽  
Hydronium Ions ◽  
Structure Factors

Polymer electrolyte fuel cells (PEFCs) are highly expected as a next-generation power supply system due to the purity of its exhaust gas, its high power density and high efficiency. The polymer electrolyte membrane is a critical component for the performance of the PEFCs and it is important to understand the nanostructure in the membrane to enhance proton transport. We have performed an atomistic analysis of the vehicular transport of hydronium ions and water molecules in the nanostructure of hydrated Nafion membrane by systematically changing the hydration level which provides insights into a connection between the nanoscopic and mesoscopic structure of ion clusters and the dynamics of hydronium ions and water molecules in the hydrated Nafion membrane. In this study, classical molecular dynamics simulations are implemented using a model of Nafion membrane which is based on DREIDING force field and newly modified and validated by comparing the density, water diffusivity, and Nafion morphology with experimental data. The simulated final density after the annealing procedure agrees with experiment within 1.3 % for various water contents and the trends that density decreases with increasing hydration level are reproduced. In addition to determination of diffusion coefficients of solvent molecules as a function of hydration level (from λ = 1 up to λ = 18), we have also calculated radial distribution functions and static structure factors not only to clarify the structure of water molecules and hydronium ions around the first solvation shell of sulfonate groups but also to validate the mesoscopic periodic structure among water clusters. The diffusion coefficient of water molecules increases with increasing hydration level and is found to be in good agreement with experimental data. The diffusion coefficient of hydronium ions has showed that general trends in the experimental data are reproduced by the simulations although the classical models have the limitation of probing hydronium dynamics. The static structure factors of liquid molecules at low wave length provide insights into the periodic structure of the inter-water clusters. These results are consistent with the Gebel’s model based on small-angle X-ray scattering that considers the dry membrane to be made of isolated spherical ionic clusters of radius ∼7.5 Å that swell with increasing hydration.

Temperature and concentration dependence of equivalent conductivity in Ca(NO3)2-CaI2-H2O system

1980 ◽  
Vol 45 (6) ◽  
pp. 1639-1645 ◽  
Author(s):  
Jindřich Novák ◽  
Ivo Sláma
Keyword(s):  
Linear Function ◽  
Concentration Dependence ◽  
Mole Fraction ◽  
Constant Temperature ◽  
Salt Concentration ◽  
Free Water ◽  
Water Molecules ◽  
Equivalent Conductivity ◽  
Calcium Salts ◽  
Fraction I

The dependence of the equivalent conductivity on the temperature and composition of the Ca(NO3)2-CaI2-H2O system was studied. The ionic fraction [I-]/([I-] + [NO-3]) was changed from 0.1 to 0.5, the mole fraction of calcium salts (assumed in anhydrous form in the presence of free water molecules) was 0.075-0.200. The equivalent conductivity was found to be a linear function of the ionic fraction at constant temperature and salt concentration.

Experimental Methodologies: Two Case Studies Investigating the Syntax- Discourse Interface

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Timothy Gupton ◽  
Tania Leal Méndez
Keyword(s):  
Experimental Data ◽  
Quantitative Data ◽  
Native Speaker ◽  
Experimental Methods ◽  
Experimental Investigations ◽  
Experimenter Bias ◽  
Current Article ◽  
Theoretical Syntax ◽  
Discourse Interface ◽  
L1 And L2

AbstractThe current article examines two experimental investigations of the syntaxdiscourse interface, which address theoretical questions in different ways: the first is an L1 investigation of Galician speakers in Gupton (2010) and the second is a dual investigation of L1 and L2 Spanish reported on in Leal Méndez & Slabakova (2011). These investigations gathered quantitative data via psycholinguistic tasks with accompanying audio utilizing the WebSurveyor platform. They involved counterbalanced designs and were followed by statistical analysis. While acknowledging that experimental data does not have primacy over intuitive data, the authors endorse the use of experimental methods of data elicitation (such as the ones already used in generative SLA research) in theoretical syntax in order to avoid experimenter bias and to get a more complete picture of native speaker intuition and competencies.

scholarly journals Self-Organization of Water Molecules Over 11-Year Solar Cycle

2021 ◽  
Author(s):  
Igor Shevchenko
Keyword(s):  
Solar Activity ◽  
Water Clusters ◽  
The Self ◽  
Self Organization ◽  
Water Molecules ◽  
Annual Variations ◽  
The Earth ◽  
Rate Of Hydrolysis ◽  
Rotation Of The Earth ◽  
Northern And Southern Hemispheres

Abstract The variations of solar activity and distribution of solar energy due to the rotation of the Earth around its axis and around the Sun exert a strong influence on the self-organization of water molecules. As a result, the rate of hydrolytic processes with the participation of water clusters displays diurnal, very large annual variations, and is also modulated by the 11-year cycles of solar activity. It also depends on the geographic latitude and can be different at the same time in the Northern and Southern Hemispheres. This phenomenon is well accounted for by the influence of muons on the self-organization of water molecules. Muons are constantly generated in the upper atmosphere by the solar wind. They reach the surface of the Earth and can penetrate to some depth underground. Buildings also absorb muons. For this reason, the rate of hydrolysis outside and inside buildings, as well as underground, can differ significantly from each other.

scholarly journals Synthesis, Single Crystal Structural Investigation, Hirshfeld Surface Analysis, Thermoanalysis and Spectroscopic Study of Two New Cu(II) and Co(II) Transition-Metal Complexes

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 986
Author(s):  
Rim Boubakri ◽  
Mirosław Szybowicz ◽  
Mariola Sadej ◽  
Sarra Soudani ◽  
Frédéric Lefebvre ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Organic Ligand ◽  
Free Water ◽  
Pyrimidine Ring ◽  
Water Molecules ◽  
Absorption Bands ◽  
Infrared And Raman Spectroscopy ◽  
Homo And Lumo ◽  
Coordinated Water

Two new complexes, [Cu(dimpyr)2(H2O)2](NO3)2.2H2O (1) and (Hamdimpy)2[CoCl4].H2O (2), with the monodentate ligand 2-amino-6-methylpyrimidin-4-(1H)-one (dimpyr) and the countercation 4-amino-2,6-dimetylpyrimidium (Hamdimpy), respectively, were prepared and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. In (1), the Cu(II) cation is tetracoordinated, in a square plan fashion, by two nitrogen atoms from the pyrimidine ring of the organic ligand and two oxygen atoms of two coordinated water molecules. In the atomic arrangement, the CuO2N2 square planes are interconnected via the formation of O-H…O hydrogen bonds involving both coordinated and free water molecules and NO3− nitrate anions to form inorganic layers parallel to the (a, b) plane at z = (2n + 1)/4. In (2), the central atom Co(II) is four-coordinated in a distorted tetrahedral fashion by four Cl− ions. The [CoCl4]2− tetrahedra are arranged parallel to the plane (110) at x = (2n + 1)/2 and the organic cations are grafted between them by establishing with them hydrogen bonds of CH…Cl and NH…Cl types. The vibrational absorption bands were identified by infrared and Raman spectroscopy. Intermolecular interactions were investigated via Hirshfeld surfaces and electronic properties such as HOMO and LUMO energies were derived. The two compounds were characterized by thermal analysis to determine their thermal behavior with respect to temperature.

scholarly journals Single and multiple excitations in double-core-hole states of free water molecules

2020 ◽  
Vol 53 (22) ◽  
pp. 224002
Author(s):  
T Marchenko ◽  
S Carniato ◽  
G Goldsztejn ◽  
O Travnikova ◽  
L Journel ◽  
...  
Keyword(s):  
Free Water ◽  
Water Molecules ◽  
Core Hole

scholarly journals DSC reveals variation in enthalpy associated with free water molecules in water-ethanol solution exposed to x-rays and magnetic field

2021 ◽  
Vol 17 (1) ◽  
pp. 07-07
Author(s):  
Nirmal Chandra Sukul ◽  
Tandra Sarkar ◽  
Atheni Konar ◽  
Md. Amir Sohel ◽  
Asmita Sengupta ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Ethanol ◽  
Free Water ◽  
Ethanol Solution ◽  
Water Molecules ◽  
X Rays ◽  
Standard Medium ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Homeopathic Drugs

Aqueous ethanol is the standard medium for all drugs used in homeopathy. X-ray and Magnetispoli ambo are 2 homeopathic drugs prepared by exposure of aqueous ethanol to x-rays and static magnetic field, respectively.Mother tinctures (MT)weresuccessively diluted with solvent 1:100 and succussed in several steps to prepare centesimal potencies 8 cH, 14 cH and 32 cH. The solvent was processed in the same way. Although identical in chemical composition (0.03 molar ethanol) and water content (96%) these preparations like the Mother tinctures and three potencies of X-ray and Magnetispoli amboexhibit different therapeutic pathological effects. Potency 8cH of each preparation was diluted with water to reach concentrations 4%, 20%, 40% and 80% ethanol. The aim of the study was to establish whether these potencies exhibited variation in free water molecules. Differential Scanning Calorimetry (DSC) of MT and potencies exhibited almost similar freezing and melting points, but they remarkably differed in freezing and melting enthalpy and free water molecules. The various dilutions of potency 8cH exhibited variation in enthalpies and free water molecules, being this variation independent of the amount of water added. We conclude that exposure of aqueous ethanol to x-rays and magnetic field, with subsequent dilution and agitation induces changes in the solvent involving free water molecules. All X-ray and Magnetispoli ambo potencies were analyzed by means of Raman spectroscopy for free water molecules. The results were compared to the ones of DSC, being more or less similar.

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