scholarly journals Measurement of the diffusion coefficient in liquids using Fresnel diffraction from a phase step

2021 ◽  
Author(s):  
Ahad Saber ◽  
Mohammad Taghi Tavassoly ◽  
Rasoul Aalipour
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Process ◽  
Water Solution ◽  
Glass Plate ◽  
Fresnel Diffraction ◽  
Parallel Beam ◽  
Plate Edge ◽  
Phase Step ◽  
A Cell ◽  
Diffraction Patterns

Abstract Fresnel diffraction from a phase step for measuring diffusion coefficient in transparent liquids is investigated. When a transparent glass plate immersed vertically in a cell containing two diffusing liquids is illuminated by a parallel beam of light, the diffraction pattern of the plate edge forms on a screen perpendicular to the beam direction and varies by diffusion. The gradient of the refractive index in the liquids is then obtained by analyzing the diffraction patterns at different times after the beginning of the diffusion process, from which the diffusion coefficient is determined. Using this method, we study the diffusion process of the sucrose-water solution and report the diffusion coefficient with a reliable accuracy.

scholarly journals Measurement of the diffusion coefficient in liquids using Fresnel diffraction from a phase step

2021 ◽  
Vol 127 (8) ◽  
Author(s):  
Ahad Saber ◽  
Mohammad Taghi Tavassoly ◽  
Rasoul Aalipour
Keyword(s):  
Diffusion Coefficient ◽  
Fresnel Diffraction ◽  
Phase Step

Identification by Electron Microdiffraction of Intermetallic Phases in a Duplex Stainless Steel

1990 ◽  
Vol 48 (2) ◽  
pp. 494-495
Author(s):  
A. Redjaïmia ◽  
J.P. Morniroli ◽  
G. Metauer ◽  
M. Gantois
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Convergent Beam Electron Diffraction ◽  
Intermetallic Phases ◽  
Small Particles ◽  
Parallel Beam ◽  
Diffraction Patterns ◽  
Average Size ◽  
Convergent Beam ◽  
Electron Microdiffraction

2D and especially 3D symmetry information required to determine the crystal structure of four intermetallic phases present as small particles (average size in the range 100-500nm) in a Fe.22Cr.5Ni.3Mo.0.03C duplex stainless steel is not present in most Convergent Beam Electron Diffraction (CBED) patterns. Nevertheless it is possible to deduce many crystal features and to identify unambiguously these four phases by means of microdiffraction patterns obtained with a nearly parallel beam focused on a very small area (50-100nm).From examinations of the whole pattern reduced (RS) and full (FS) symmetries the 7 crystal systems and the 11 Laue classes are distinguished without ambiguity (1). By considering the shifts and the periodicity differences between the ZOLZ and FOLZ reflection nets on specific Zone Axis Patterns (ZAP) which depend on the crystal system, the centering type of the cell and the glide planes are simultaneously identified (2). This identification is easily done by comparisons with the corresponding simulated diffraction patterns.

Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination

1990 ◽  
Vol 48 (2) ◽  
pp. 490-491
Author(s):  
Ryuichiro Oshima ◽  
Shoichiro Honda ◽  
Tetsuo Tanabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Single Crystal ◽  
Mixed Solution ◽  
Parallel Beam ◽  
Defect Clusters ◽  
Float Zone ◽  
Transmission Electron ◽  
Extra Electron ◽  
Diffraction Patterns

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.

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.

scholarly journals Fresnel diffraction patterns as accelerating beams

2013 ◽  
Vol 104 (3) ◽  
pp. 34007 ◽  
Author(s):  
Yiqi Zhang ◽  
Milivoj R. Belić ◽  
Huaibin Zheng ◽  
Zhenkun Wu ◽  
Yuanyuan Li ◽  
...  
Keyword(s):  
Fresnel Diffraction ◽  
Diffraction Patterns

Powder X-ray structural studies and reference diffraction patterns for three forms of porous aluminum terephthalate, MIL-53(A1)

2019 ◽  
Vol 34 (3) ◽  
pp. 216-226 ◽  
Author(s):  
W. Wong-Ng ◽  
H. G. Nguyen ◽  
L. Espinal ◽  
D. W. Siderius ◽  
J. A. Kaduk
Keyword(s):  
High Temperature ◽  
Metal Organic Framework ◽  
Space Group ◽  
X Ray ◽  
Porous Aluminum ◽  
Refinement Method ◽  
Three Samples ◽  
Metal Organic ◽  
A Cell ◽  
Diffraction Patterns

Powder X-ray diffraction patterns for three forms of MIL-53(Al), a metal organic framework (MOF) compound with breathing characteristics, were investigated using the Rietveld refinement method. These three samples are referred to as the MIL-53(Al)as-syn (the as synthesized sample), orthorhombic, Pnma, a = 17.064(2) Å, b = 6.6069(9) Å, c = 12.1636(13) Å, V = 1371.3(2) Å3, Z = 4), MIL-53(Al)LT-H (low-temperature hydrated phase, monoclinic P21/c, a = 19.4993(8) Å, b = 15.2347(6) Å, c = 6.5687(3) Å, β = 104.219(4) °, V = 1891.55(10) Å3, Z = 8), and MIL-53(Al)HT-D (high-temperature dehydrated phase, Imma, a = 6.6324(5) Å, b = 16.736(2) Å, c = 12.840(2), V = 1425.2(2) Å3, Z = 4). The crystal structures of the “as-syn” sample and the HT-D sample are confirmed to be the commonly adopted ones. However, the structure of the MIL-53(Al)LT-H phase is confirmed to be monoclinic with a space group of P21/c instead of the commonly accepted space group Cc, resulting in a cell volume double in size. The structure has two slightly different types of channel. The pore volumes and pore surface area were estimated to be 0.11766 (8) cm3/g and 1461.3(10) m2/g for MIL-53(Al)HT-D (high-temperature dehydrated phase), and 0.08628 (5) cm3/g and 1401.6 (10) m2/g for MIL-53(Al)as-syn phases, respectively. The powder patterns for the MIL-53(Al)as-syn and MIL-53(Al)HT-D phases are reported in this paper.

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