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.

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.

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.

A CHAOS-BASED ROBUST WATERMARKING ALGORITHM FOR RIGHTFUL OWNERSHIP PROTECTION

2011 ◽  
Vol 11 (04) ◽  
pp. 471-493 ◽  
Author(s):  
SANJAY RAWAT ◽  
BALASUBRAMANIAN RAMAN
Keyword(s):  
Chaotic Map ◽  
Singular Values ◽  
Extraction Process ◽  
Reference Image ◽  
Secret Key ◽  
Watermark Embedding ◽  
Series Of Experiments ◽  
Hybrid Watermarking ◽  
The Fourier Transform ◽  
Value Decomposition

Traditional singular value decomposition (SVD)-based watermarking schemes, already exist for watermark embedding on the image as a whole. In this paper, a chaos-based hybrid watermarking scheme that combines the Fourier transform and the SVD is proposed. Instead of modifying the original cover image to embed the watermark, a reference image is formed in the proposed scheme to embed the watermark. The watermark is embedded by modifying the singular values of the reference image. The watermark extraction process is semi-blind, i.e. it does not require the original image. Chaotic map is used to shuffle the pixel positions of the image, which can be used as a secret key to improve the security of the algorithm. The security of the scheme is further strengthened by applying Zig-Zag scan on the watermark before embedding. A series of experiments is conducted to prove the fidelity and robustness property of the proposed scheme. Experimental results show that our scheme is strong enough to resist common image-processing attacks, geometric distortions, and some composite attacks. The results also show that our scheme outperforms related works in most cases.

Simulation and Computation of Diffusion in Solids

2012 ◽  
Vol 182-183 ◽  
pp. 933-936
Author(s):  
Zhi Hong Hou ◽  
Shi Yong Luo
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Process ◽  
Diffusion Coefficients ◽  
Database Management ◽  
Concentration Distribution ◽  
Database Management System ◽  
Critical Conditions ◽  
Second Law ◽  
Diffusion In Solids ◽  
Diffusion Computation

A computation software on diffusion computation in solids was developed. The software includes two sub-modules of “database management system (DBMS)” and "Evaluation & prediction". The “DBMS” deals with the diffusion coefficients gathered from reported documents and the data evaluated according to some rules, besides, it can provide users with retrieval of diffusion coefficients. Based on the solutions to the Fick’s first law and the Fick’s second law in the four typical critical conditions, the "Evaluation & prediction" sub-module gives the predication of concentration distribution after diffusion process in solids or computation for diffusion coefficient.

scholarly journals Problems of seasonality of sugar production from beets

2020 ◽  
Vol 82 (1) ◽  
pp. 64-69 ◽  
Author(s):  
V. A. Golybin ◽  
V. A. Fedoruk ◽  
N. A. Matvienko
Keyword(s):  
Diffusion Process ◽  
Raw Materials ◽  
Sugar Content ◽  
Extraction Process ◽  
Feed Water ◽  
Negative Consequences ◽  
Root Crops ◽  
Initial Stage ◽  
Beet Pulp ◽  
Physical And Chemical

In recent years, the annual processing of sugar beet in Russia is 45 million tons or more, which allows to produce white sugar in the amount of 6.0 million tons or more. during the production season, the quality of beets does not remain constant – not only its sugar content changes, but also the content of harmful soluble non-sugars, as well as physical and chemical parameters - the mass of root crops decreases due to wilting, reducing turgor, respiration and germination, rotten mass appears as a result of microbiological and enzymatic processes and the formation of foci of mucous bacteriosis. One of the main tasks of improving the diffusion process is to increase the elasticity of beet tissue and reduce the intensity of the transition of pectin substances into the diffusion juice. This goal is achieved by using effective chemical reagents in the composition of the feed water introduced into the diffusion apparatus, as well as processing of beet chips immediately before the sucrose extraction process; reducing the temperature of desugarisation of beet pulp in the diffusion apparatus in the allowable interval. The method of intensification of sucrose extraction using the method of treatment of feed water in an electric field is proposed. Improvement of the dispersed composition of the resulting sediment particles is facilitated by the return to the preliming of the carbonate suspension of juice II saturation, carried out using an activated suspension of filter perlite. The homogeneity of calcium carbonate particles and correspondingly high filtration rates of saturation juice are formed due to the active circuit of the internal circulation of the juice. The use of the proposed recommendations during the implementation of technological processes in their implementation in modern equipment of the diffusion process and purification of the obtained juice allow to minimize the negative consequences of beet processing both at the initial stage of the production season when technically not ripe root crops are received, and during the end of the season when processing raw materials of reduced quality.

scholarly journals Dispersion of watermelon rinds as secondary raw materials in technologies of pectin-containing extracts and film structures

2021 ◽  
Vol 17 (5) ◽  
pp. 31-42
Author(s):  
G. S. Meshcheryakova ◽  
A. H.-H. Nugmanov ◽  
I. Yu. Aleksanian ◽  
Yu. A. Maksimenko ◽  
E. V. Sokolova
Keyword(s):  
Original Film ◽  
Raw Materials ◽  
Protective Coatings ◽  
Extraction Process ◽  
Complex Problem ◽  
Film Material ◽  
Resource Base ◽  
Preliminary Preparation ◽  
Sulfuric And Hydrochloric Acids ◽  
Natural Losses

The development of protective coatings based on pectin substances that serve as natural structure-forming agents developed from a secondary resource base is focused on removing a complex problem in the production of finished products by deep processing of basic raw materials and developing an original film material. At the same time, the technical result of obtaining pectin-containing film structures is their ability to protect food products from microbiological spoilage, natural losses during storage and the preservation of quality and safety indicators. An important preparatory procedure that determines the efficiency and intensity of extraction processes can be attributed to the operation of dispersing the feedstock, since it directly affects the size of the contact surface area of the phases involved in mass transfer. However, it is clear that the greater the degree of grinding, the higher the efficiency of the process, but an excessive increase can lead to additional unjustified energy costs and, as a result, to an increase in the cost of the finished products sold. In this regard, the purpose of the research is to analyze existing technologies for producing pectin-containing extracts, in which watermelon rinds can be used as secondary resources and to intensify the extraction process by conducting a rational preparatory procedure for grinding the raw materials. The object of the research are watermelon rinds as non-recyclable waste from processing watermelon raw materials. According to the obtained graphs, and taking into account the high rates of gelatinization of the obtained pectin extracts, it is possible to recommend a complex treatment of watermelon rinds, including, in addition to the operations of preliminary preparation of raw materials, ultrasonic exposure and acid hydrolysis, and it is desirable to use food acids, for example, acetic or citric, instead of aggressive sulfuric and hydrochloric acids. As a result of the study of the dispersed composition, it has been concluded that the average equivalent particle size of the dispersed raw materials does not exceed the recommended limits, that is, the result obtained can be considered acceptable.

Sign in / Sign up

Export Citation Format

Share Document