Evaluation of partial and total structure factors, diffusion coefficient and compressibility of liquid phase of glassy calcium-aluminium alloy

1992 ◽  
Vol 146 ◽  
pp. 294-300 ◽  
Author(s):  
R.V. Gopala Rao ◽  
R. Venkatesh
Keyword(s):  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Aluminium Alloy ◽  
Structure Factors ◽  
Total Structure

scholarly journals Insights into the interactions and dynamics of a DES formed by phenyl propionic acid and choline chloride

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parisa Jahanbakhsh Bonab ◽  
Alireza Rastkar Ebrahimzadeh ◽  
Jaber Jahanbin Sardroodi
Keyword(s):  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Propionic Acid ◽  
Structural Parameters ◽  
Choline Chloride ◽  
Self Diffusion ◽  
Phenyl Propionic Acid ◽  
Donor And Acceptor ◽  
Experimental Values ◽  
Self Diffusion Coefficient

AbstractDeep eutectic solvents (DESs) have received much attention in modern green chemistry as inexpensive and easy to handle analogous ionic liquids. This work employed molecular dynamics techniques to investigate the structure and dynamics of a DES system composed of choline chloride and phenyl propionic acid as a hydrogen bond donor and acceptor, respectively. Dynamical parameters such as mean square displacement, liquid phase self-diffusion coefficient and viscosity are calculated at the pressure of 0.1 MPa and temperatures 293, 321 and 400 K. The system size effect on the self-diffusion coefficient of DES species was also examined. Structural parameters such as liquid phase densities, hydrogen bonds, molecular dipole moment of species, and radial and spatial distribution functions (RDF and SDF) were investigated. The viscosity of the studied system was compared with the experimental values recently reported in the literature. A good agreement was observed between simulated and experimental values. The electrostatic and van der Waals nonbonding interaction energies between species were also evaluated and interpreted in terms of temperature. These investigations could play a vital role in the future development of these designer solvents.

An Engineering Calculation Method for Multi-Component Stagnant Droplet Evaporation With Finite Diffusivity

1994 ◽  
Author(s):  
J. S. Chin
Keyword(s):  
Heat Transfer ◽  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Vapor Pressure ◽  
Molecular Mass ◽  
Calculation Method ◽  
Engineering Calculation ◽  
Droplet Evaporation ◽  
Diffusion Resistance ◽  
Distillation Curve

A practical engineering calculation method has been formulated for commercial multicomponent fuel stagnant droplet evaporation with variable finite mass and thermal diffusivity. Instead of solving the transient liquid phase mass and heat transfer partial differential equation set, a totally different approach is used. With zero or infinite mass diffusion resistance in liquid phase, it is possible to obtain vapor pressure and vapor molecular mass based on the distillation curve of these turbine fuels. It is determined that Peclet number (Pef) is a suitable parameter to represent the mass diffusion resistance in liquid phase. The vapor pressure and vapor molecular mass at constant finite Pef is expressed as a function of finite Pef, vapor pressure, and molecular mass at zero Pef and infinite Pef. At any time step, with variable finite Pef, the above equation is still valid, and PFsPef=∞, PFsPef=0, MfvPef=∞, MfvPef=0 are calculated from PFsPef≡∞, PFsPef≡0, MfvPef≡∞, MfvPef≡0, thus PFs and Mfv can be determined in a global way which eventually is based on the distillation curve of fuel. The explicit solution of transient heat transfer equation is used to have droplet surface temperature and droplet average temperature as a function of surface Nusselt number and non-dimensional time. The effect of varying com position of multi-component fuel evaporation is taken into account by expressing the properties as a function of molecular mass, acentric factor, critical temperature, and critical pressure. A specific calculation method is developed for liquid fuel diffusion coefficient, also special care is taken to calculate the binary diffusion coefficient of fuel vapor-air in gaseous phase. The effect of Stefan flow and natural convection has been included. The predictions from the present evaporation model for different turbine fuels under very wide temperature ranges have been compared with experimental data with good agreement.

X-ray Investigations of Liquid Bismuth-Copper Alloys

2000 ◽  
Vol 55 (3-4) ◽  
pp. 381-389 ◽  
Author(s):  
J. Nomssi Nzali ◽  
W. Hoyer
Keyword(s):  
Copper Alloys ◽  
X Ray Diffraction ◽  
Model Calculations ◽  
Experimental Procedure ◽  
X Ray ◽  
X Ray Scattering ◽  
Structure Factors ◽  
Reverse Monte Carlo Simulation ◽  
Square Well ◽  
Total Structure

Liquid copper, bismuth, and eleven bismuth-copper alloys were investigated at temperatures above the liquidus with X-ray diffraction. The experimental procedure was adjusted to reduce the effects of evaporation. The Faber-Ziman total structure factors S(Q) feature a splitting of the first maximum and negative values for Q around 1 Å -1 in a large concentration range. The results are compared to previous neutron diffraction results by Zaiss and Steeb, to square-well potential model calculations by Gopala Rao and Satpathy and to a simple segregation model. The segregation model reproduces the features qualitatively. Partial structure factors are assessed by fitting both neutron and X-ray scattering results with reverse Monte-Carlo simulation

Schallgeschwindigkeitsmessung in Bi-Cu Schmelzen zur Bestimmung der Kompressibilität und der partiellen Strukturfaktoren / Sound Velocity, Compressibility, und Partial Structure Factors (q = 0) in Bi-Cu Melts

1974 ◽  
Vol 29 (12) ◽  
pp. 1890-1897 ◽  
Author(s):  
Helmut Ebert ◽  
Jochen Höhler ◽  
Siegfried Steeb
Keyword(s):  
Sound Velocity ◽  
Linear Combination ◽  
Transition Region ◽  
Density Fluctuations ◽  
Partial Structure ◽  
Cu Alloys ◽  
Structure Factors ◽  
Velocity Of Ultrasound ◽  
Total Structure ◽  
Versus Concentration

The adiabatic velocity of ultrasound in molten Bi-Cu alloys was measured at various concentrations and temperatures. For the alloys with concentrations between 40 and 80 a/0 Cu the μ(T)- curves consist of two linear regions with a transition region. Within the concentration range mentioned ⊿u/⊿T and the compressibility show respectively positive and negative deviations from linearity. The deviations can be detected at temperatures up to 1200 C. The total structure factors I(O) for Bi and Cu as well as the partial structure factors aij(O) were obtained. aCuCu(O) shows rather high values, indicating the existence of inhomogeneities containing mainly Cu-atoms. The slope of ⊿Nj' [which is a linear combination of the aij (O)] versus concentration is negative. From this fact follows that segregation must exist in these melts. This also follows from the rather large density fluctuations given by the partial factors SCC(O) obtained in this work.

Structural Investigation of the Metallic Glasses Mg85.5Cu14.5 and Mg70Zn30

1983 ◽  
Vol 38 (2) ◽  
pp. 142-148 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
W. Sperl ◽  
S. Steeb
Keyword(s):  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
Order Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Factors ◽  
Similar Chemical ◽  
Total Structure

Abstract The total structure factors as well as the total pair correlation functions for amorphous Mg85.5Cu14.5 (by neutron and X-ray diffraction) and for amorphous Mg70Zn30 (by X-ray diffraction) were determined. Both alloys show similar chemical short range order effects. From the total pair correlation function of the Mg85.5Cu14.5 glass, partial coordination numbers and atomic distances could be extracted. Comparison with the structure of crystalline Mg2Cu suggests that the short range order around the copper atoms is similar in the amorphous and the crystalline phase. The densities of both amorphous alloys were measured yielding negative excess volumina.

X-Ray Diffraction with Molten AuxMn100-x-Alloys

1995 ◽  
Vol 50 (9) ◽  
pp. 831-836
Author(s):  
R. M. Hagenmayer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Correlation Functions ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Pair Correlation Functions ◽  
X Ray ◽  
Structure Factors ◽  
Total Structure

Abstract The molten alloys Au28.5Mn71.5 and Au68Mn32 are investigated with the energy dispersive X-ray diffraction method which works rather fast so that the evaporation loss of Mn from the molten alloys is kept low. From the observed prepeak follows that both melts are compound-forming but the gold rich melt Au68Mn32 shows only 50% of the short range order existent within the Au28.5Mn71.5 melt. Total structure factors and total pair correlation functions are discussed.

Isotopic quantum effects in the structure of liquid ethanol

2002 ◽  
Vol 80 (9) ◽  
pp. 1059-1068 ◽  
Author(s):  
B Tomberli ◽  
C J Benmore ◽  
J Neuefeind ◽  
P A Egelstaff
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Ambient Pressure ◽  
High Energy ◽  
Radiation Scattering ◽  
Structure Factors ◽  
Structural Differences ◽  
Order Of Magnitude ◽  
Total Structure Factor ◽  
Total Structure

High-energy electromagnetic-radiation-scattering techniques have been used to measure the structural differences between five isotopic samples of ethanol (CH3CH2OH, CD3CD2OD, CD3CH2OH, CH3CH2OD, and CH3CD2OH) at room temperature and ambient pressure. The differences in the X-ray structure factors between several pairs of isotopes, ΔSX(Q), are shown to have maximum amplitudes that are on the order of a few percent compared to the total structure factor for CH3CH2OH. Our uncertainties are an order of magnitude smaller than those of early gamma-ray measurements on methanol (C.J. Benmore and P.A. Egelstaff. J. Phys. Condens. Matter, 8, 9429 (1996)). These studies have shown that isotopic structural differences in room-temperature ethanol vary as a function of substitution site and are in qualitative agreement with similar differences found in liquid methanol. PACS Nos.: 61.20-p, 61.25E, 61.10-E

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