scholarly journals Calculation of parameters of elementary nanocrystals of liquid metals at melting temperature

2021 ◽  
pp. 16-18
Author(s):  
E. I. Marukovich ◽  
V. Yu. Stetsenko ◽  
A. V. Stetsenko
Keyword(s):  
Diffusion Coefficient ◽  
Melting Temperature ◽  
Liquid Metals ◽  
Solidification Rate ◽  
High Solidification Rate ◽  
Calculation Of Parameters ◽  
High Diffusion ◽  
High Diffusion Coefficient

Method of calculation and calculated values of parameters of elementary nanocrystals of liquid metals at melting temperature are given. It has been shown that radii of elementary nanocrystals are from 2 nm to 12 nm, and the number of atoms in each elementary nanocrystal varies from 2000 to 100000. This provides liquid metals with a high solidification rate and explains the abnormally high diffusion coefficient in liquid metals compared to solid metals.

scholarly journals A high diffusion coefficient for coenzyme Q10 might be related to a folded structure

FEBS Letters ◽  
1998 ◽  
Vol 426 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Rita Casadio ◽  
Piero Fariselli ◽  
Giorgio Lenaz
Keyword(s):  
Diffusion Coefficient ◽  
Coenzyme Q10 ◽  
High Diffusion ◽  
Folded Structure ◽  
High Diffusion Coefficient

Another View of Carbon Dioxide and Retrolental Fibroplasia

PEDIATRICS ◽  
1983 ◽  
Vol 71 (4) ◽  
pp. 665-666
Author(s):  
G. A. GOLE ◽  
B. J. GANNON
Keyword(s):  
Carbon Dioxide ◽  
Diffusion Coefficient ◽  
Short Distance ◽  
High Flow ◽  
Choroidal Circulation ◽  
Retrolental Fibroplasia ◽  
High Diffusion ◽  
High Diffusion Coefficient

To the Editor.— Wolbarsht et al1 advanced several hypotheses in their letter regarding the role of CO2 in retrolental fibroplasia. We take issue with their letter on the following grounds: 1. No evidence is presented that levels of retinal Pco2 rise during O2 induced retinal vasoconstriction. CO2 has a high diffusion coefficient, 20 times that of oxygen2 and we suggest that such CO2 produced in the retina would rapidly diffuse the short distance to the high-flow choroidal circulation. 2.

CALCULATION OF PARAMETERS OF A DIFFUSION PROCESS WITH A CONCENTRATION-DEPENDENT DIFFUSION COEFFICIENT

2020 ◽  
Author(s):  
Е.Г. СТЕПАНОВА ◽  
Б.Ю. ОРЛОВ ◽  
М.А. ПЕЧЕРИЦА
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Process ◽  
Transfer Problem ◽  
Extraction Process ◽  
Electrochemical Activation ◽  
Calculation Of Parameters ◽  
Sucrose Solutions ◽  
Diffusion Transfer ◽  
Preliminary Preparation ◽  
Series Of Experiments

Приведено решение нелинейной задачи диффузионного переноса с учетом предварительной подготовки экстрагента методом электрохимической активации. Для расчета параметров процесса использована капиллярная модель. Показаны результаты расчета симплекса концентраций от числа Фурье Е = f(Fo). Представлены экстракционные кривые в чистых сахарных растворах с различными видами экстрагентов и температурами процесса 20 и 70°С. Аналитическая обработка кинетических кривых позволила определить основные параметры диффузионного процесса экстрагирования сахарозы. Проведен полный двухфакторный эксперимент lnЕ= f(С; τ), получено уравнение регрессии и построена поверхность отклика, которая исследована методом неопределенных множителей Лагранжа с получением оптимальных значений для проведенной серии опытов С = 15,4% и τ = 750 с. Выполненные расчеты позволяют моделировать внутренний массоперенос экстрагирования концентрационно-зависимого коэффициента диффузии сахарозы при наложении электрического поля при обработке экстрагента. We present a solution to the nonlinear diffusion transfer problem, taking into account the preliminary preparation of the extractant by electrochemical activation (ECHA). A capillary model is used to calculate the process parameters. The results of calculating the concentration simplex from the Fourier number E= f(Fo) are shown. The description of the laboratory installation, the method of the process, and the modes of ECHA preparation of extractants are given. Extraction curves in pure sucrose solutions with different types of extractants and process temperatures are presented. Analytical processing of the kinetic curves of the sucrose extraction process for the regular stage of the process allowed us to determine the main parameters of the diffusion process. A complete two-factor experiment lnE= f(C; τ) was performed. A regression equation was obtained and the response surface was constructed, which was studied by the method of indeterminate Lagrange multipliers to obtain optimal values for the series of experiments С = 15,4% and τ = 750 s. The calculations performed allow us to model the internal mass transfer of extraction of the concentration-dependent sucrose diffusion coefficient when an electric field is applied during processing of the extractant.

Vacancy Formation Energy and Kinetic Properties of Liquid Metals

2021 ◽  
Vol 880 ◽  
pp. 43-48
Author(s):  
Yuri N. Starodubtsev ◽  
V.S. Tsepelev
Keyword(s):  
Diffusion Coefficient ◽  
Kinematic Viscosity ◽  
Formation Energy ◽  
Liquid Metals ◽  
Linear Regression Analysis ◽  
Vacancy Formation Energy ◽  
Vacancy Formation ◽  
Kinetic Properties ◽  
Self Diffusion ◽  
Self Diffusion Coefficient

We investigated the relationship of the vacancy formation energy with kinematic viscosity and self-diffusion coefficient in liquid metals at the melting temperature. Formulas are obtained that relate experimental values of the vacancy formation energy, kinematic viscosity, and self-diffusion coefficient to the atomic size and mass, the melting and Debye temperatures. The viscosity and self-diffusion parameters are introduced. The ratio of these parameters to vacancy formation energy is equal to dimensionless constants. It is shown that the formulas for viscosity and self-diffusion differ only in dimensionless constants; the values of these constants are calculated. Linear regression analysis was carried out and formulas with the highest adjusted coefficient of determination were identified. The calculated values of the self-diffusion coefficient for a large number of liquid metals are presented.

Formation of Bulk Nanostructured Al3Ni from Elemental Micropowders Using High-Pressure Torsion

2013 ◽  
Vol 765 ◽  
pp. 378-382 ◽  
Author(s):  
Ali Alhamidi ◽  
Kaveh Edalati ◽  
Zen Ji Horita
Keyword(s):  
High Pressure ◽  
Diffusion Coefficient ◽  
Shear Strain ◽  
Melting Temperature ◽  
High Pressure Torsion ◽  
Processing Temperature ◽  
Powder Mixtures

The formation of bulk nanograined Al3Ni intermetallics from elemental micro-powder mixtures of Al-25 mol.% Ni are studied after processing by high-pressure torsion (HPT) for various turns at 473 K and at 573 K. It is found that nanograined Al3Ni intermetallics with high angles of misorientation are produced at temperatures well below the melting temperature. The fraction of Al3Ni intermetallics increases by increasing the shear strain and increasing the HPT processing temperature. During HPT, both Ni and Al atoms diffuse significantly in each other with a diffusion coefficient well comparable to the atomic interdiffusion in the Al3Ni intermetallic at its melting temperature.

Tracer Impurity Diffusion in Liquid Metals: Au in Ga

1974 ◽  
Vol 29 (6) ◽  
pp. 959-960 ◽  
Author(s):  
P.-E. Eriksson ◽  
S. J. Larsson
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Low Temperatures ◽  
Arrhenius Plot ◽  
Liquid Metals ◽  
Impurity Diffusion ◽  
Straight Line ◽  
Linear Plot

The diffusion coefficient of 198Au in liquid Ga has been measured between 35 and 460 °C. The results can be represented by a linear plot of D vs T or by an Arrhenius plot. The latter yields the parameters D0 = 4.9·10-4 cm2/s and Q = 2.65 kcal/mol. However, some distinct departures from the straight line characteristics, showing a considerably higher “activation energy” at the low temperatures, suggest the possibility that clusters composed of two or several atoms may partake in diffusion.

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