Gas-Solid Exchange Reactions: Zinc Vapor and Monocrystalline Zinc Telluride

1971 ◽  
Vol 49 (11) ◽  
pp. 1953-1956 ◽  
Author(s):  
E. A. Secco ◽  
Richard Swee-Chye Yeo
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Process ◽  
Single Crystals ◽  
Zinc Telluride ◽  
Static System ◽  
Rate Data ◽  
Vacancy Mechanism ◽  
Zinc Vapor ◽  
Exchange Reactions ◽  
Radioactive Zinc

The exchange reaction between radioactive zinc vapor and single crystals of zinc telluride was studied in a static system in the temperature range 760–860 °C and PZn = 0.10 atm.The experimental rate data are consistent with a diffusion process which is interpreted in terms of a simple vacancy mechanism. The diffusion coefficient is given by[Formula: see text]

GAS–SOLID EXCHANGE REACTIONS: ZINC VAPOR AND POLYCRYSTALLINE ZINC SULPHIDE

1964 ◽  
Vol 42 (6) ◽  
pp. 1396-1400 ◽  
Author(s):  
E. A. Secco
Keyword(s):  
Zinc Sulphide ◽  
Static System ◽  
Zinc Vapor ◽  
Exchange Reactions ◽  
Polycrystalline Zinc ◽  
Diffusion Controlled ◽  
Fraction Versus ◽  
Exchange Kinetics ◽  
Kinetics Of ◽  
Initial Process

The exchange kinetics of zinc vapor with polycrystalline zinc sulphide, wurtzite structure, have been studied in a static system in the temperature range 720–960 °C.Plots of log10(1−α*), i.e. exchange fraction, versus time reveal two processes. The initial process is a rapid simple exchange, for which the data fit a first-order rate law and which persists to a depth of 15–18 molecular thicknesses. At this depth the second, slower process, which appears to be diffusion-controlled, sets in. Kinetic and structural interpretations of these results along with the existing data on Zn–ZnO exchange are discussed.

Gas–solid exchange reactions: Zinc vapor and polycrystalline zinc selenide

1968 ◽  
Vol 46 (10) ◽  
pp. 1621-1624 ◽  
Author(s):  
E. A. Secco ◽  
Chien-Huo Su
Keyword(s):  
Zinc Selenide ◽  
Static System ◽  
Zinc Vapor ◽  
Exchange Reactions ◽  
Polycrystalline Zinc ◽  
Diffusion Controlled ◽  
Initial Stage ◽  
Exchange Kinetics ◽  
Kinetics Of ◽  
Exchange Data

The exchange kinetics of zinc vapor with polycrystalline zinc selenide have been studied in a static system in the temperature range 720–800 °C.The kinetic data are consistent with a diffusion-controlled process from the initial stage, in contrast with existing exchange data on ZnO and ZnS powders. The diffusion equation is given as:[Formula: see text]

Stochastic Modelling of Particle Segregation in a Horizontal Drum Mixer

1992 ◽  
Vol 57 (10) ◽  
pp. 2100-2112 ◽  
Author(s):  
Vladimír Kudrna ◽  
Pavel Hasal ◽  
Andrzej Rochowiecki
Keyword(s):  
Differential Equation ◽  
Diffusion Coefficient ◽  
Stochastic Model ◽  
Diffusion Process ◽  
Stochastic Modelling ◽  
Solid Particles ◽  
Kolmogorov Equation ◽  
Particle Segregation ◽  
Drum Mixer ◽  
Horizontal Drum

A process of segregation of two distinct fractions of solid particles in a rotating horizontal drum mixer was described by stochastic model assuming the segregation to be a diffusion process with varying diffusion coefficient. The model is based on description of motion of particles inside the mixer by means of a stochastic differential equation. Results of stochastic modelling were compared to the solution of the corresponding Kolmogorov equation and to results of earlier carried out experiments.

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.

Formation and Characterization of CuPt-A type Ordered Structure in Cadmium Zinc Telluride Single Crystals

CrystEngComm ◽  
2022 ◽  
Author(s):  
Wanzhong Li ◽  
Jian Sun ◽  
Chong Deng
Keyword(s):  
Solar Cells ◽  
Single Crystals ◽  
Cadmium Zinc Telluride ◽  
Zinc Telluride ◽  
Radiation Detectors ◽  
Ordered Structure ◽  
Ordered Phases ◽  
Different Types ◽  
Cadmium Zinc

Cadmium Zinc Telluride (CdZnTe) single crystals have been widely ultilized in various photoelectron devices such as radiation detectors and solar cells. Different types of ordered phases have also been investigated...

Gas Diffusion and Re-Diffusion in Polyethylene Foams

2009 ◽  
Vol 283-286 ◽  
pp. 583-588
Author(s):  
J. Escudero ◽  
J. Lázaro ◽  
E. Solórzano ◽  
Miguel A. Rodríguez-Pérez ◽  
Jose A. de Saja
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Process ◽  
Static Loading ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Gas Diffusion ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Compressive Creep ◽  
Closed Cell

In this work, the effective diffusion coefficient of the gas contained in closed cell polyethylene foams under static loading is measured. To do this, compressive creep experiments were performed on low density polyethylene foams produced under a gas diffusion process. Density dependence of this coefficient has been analysed as well as the variation of pressure with time inside the cells. Finally, immediately after compressive creep, the recovery behaviour of the foams was also characterised. Different abilities for recovering were observed depending on the density of the foam and the absolute recovery resulted independent of the initial stress applied.

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