CH4 Direct Reduction of In-Flight Fe3O4 Concentrate Particles

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Bahador Abolpour ◽  
M. Mehdi Afsahi ◽  
Ataallah Soltani Goharrizi
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Fine Particles ◽  
Direct Reduction ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Dynamic Motion ◽  
Magnetite Ore ◽  
Model Predictions ◽  
Kinetics Of

Abstract In this study, reduction of in-flight fine particles of magnetite ore concentrate by methane at a constant heat flux has been investigated both experimentally and numerically. A 3D turbulent mathematical model was developed to simulate the dynamic motion of these particles in a methane content reactor and experiments were conducted to evaluate the model. The kinetics of the reaction were obtained using an optimizing method as: [-Ln(1-X)]1/2.91 = 1.02 × 10−2dP−2.07CCH40.16exp(−1.78 × 105/RT)t. The model predictions were compared with the experimental data and the data had an excellent agreement.

scholarly journals Modelling Macrophage Infiltration into Avascular Tumours

2002 ◽  
Vol 4 (1) ◽  
pp. 21-38 ◽  
Author(s):  
C. E. Kelly ◽  
R. D. Leek ◽  
H. M. Byrne ◽  
S. M. Cox ◽  
A. L. Harris ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Spatial Structure ◽  
Random Motion ◽  
Numerical Results ◽  
Macrophage Infiltration ◽  
Numerical Techniques ◽  
Model Predictions ◽  
Independent Experimental Data

In this paper a mathematical model that describes macrophage infiltration into avascular tumours is presented. The qualitative accuracy of the model is assessed by comparing numerical results with independent experimental data that describe the infiltration of macrophages into two types of spheroids: chemoattractant-producing (hepa-1) and chemoattractant-deficient (or C4) spheroids. A combination of analytical and numerical techniques are used to show how the infiltration pattern depends on the motility mechanisms involved (i.e. random motion and chemotaxis) and to explain the observed differences in macrophage infiltration into the hepa-1 and C4 spheroids. Model predictions are generated to show how the spheroid's size and spatial structure and the ability of its constituent cells influence macrophage infiltration. For example, chemoattractant-producing spheroids are shown to recruit larger numbers of macrophages than chemoattractant-deficient spheroids of the same size and spatial structure. The biological implications of these results are also discussed briefly.

Pretreatment of Textile Industry Wastewaters with Ozone

1994 ◽  
Vol 29 (9) ◽  
pp. 151-160 ◽  
Author(s):  
M. Tzitzi ◽  
D. V. Vayenas ◽  
G. Lyberatos
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Textile Industry ◽  
Batch Studies ◽  
Cod Reduction ◽  
Industrial Wastewaters ◽  
Model Predictions ◽  
Textile Wastewaters

Ozonation of textile industrial wastewaters was examined in CSTR and batch studies. Experiments were done for various types of textile wastewaters and for different reaction and retention times. Much better results were obtained using ozonation after the coagulation-precipitation stage. Also a mathematical model was developed, able to describe wastewater decolonization and COD reduction. In all cases the comparison between the model predictions and the experimental data was satisfactory.

The Dynamics of Liquid Cooling in Half-Coil Jackets

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Jayakumar Natesan Subramanian ◽  
Farouq S. Mjalli
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Liquid Temperature ◽  
Liquid Cooling ◽  
Shell Side ◽  
Stirred Vessel ◽  
Model Predictions ◽  
Temperature Dynamics ◽  
The Heat Transfer Coefficient

The heat transfer cooling of a hot liquid in a stirred vessel has been studied experimentally with coolant flowing through a half-coil around the vessel. Correlations have been developed for the heat transfer coefficient of the half coil jacket. A mathematical model for the half coil jacket liquid temperature dynamics and its analytical solution is used to find the shell side temperature profile as a function of time. It is found that the model predictions are in satisfactory agreement with the experimental data and that the developed correlation is superior to previously published correlations for similar systems.

scholarly journals Drying kinetics of Chinese garlic (Allium tuberosum) and its effect on color

2020 ◽  
Vol 42 ◽  
pp. e8
Author(s):  
Paula De Almeida Rios ◽  
Ednilton Tavares De Andrade ◽  
Kátia Soares Moreira ◽  
Filipe Da Silva De Oliveira ◽  
Bárbara Lemes Outeiro Araújo
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Air Temperature ◽  
Linear Regression Analysis ◽  
Drying Kinetics ◽  
Allium Tuberosum ◽  
Thin Slices ◽  
The Mathematical Model ◽  
Quasi Newton ◽  
Kinetics Of

Dehydrated garlic is an important component both for culinary and medicinal purposes. However, there is a scarcity of studies that characterizes its drying kinetics. Thus, the objective of this work was to study the drying kinetics of Chinese garlic (Allium tuberosum), as well as to analyze the color effect resulting from each treatment. The garlic bulbs were cut into thin slices with a width of 2 and 3 mm, subjected to the drying air temperature of 35, 45, 55 and 70 °C in a mechanical dryer of a fixed layer with forced convection. Was performed a non-linear regression analysis by the Quasi-Newton method, for adjustment to 11 mathematical models to the experimental data of drying. The Midilli equation was the mathematical model that best characterized all the drying temperatures, for the experimental data. The diffusion coefficient presented values between 1.46 x 10-11 and 7.32 x 10-11 m2.s-1. The increase of the drying air temperature caused the dimming of the samples with a reduction of the L* coordinate and reduction of the yellow of the samples according to the coordinate results h*. The temperature of 70 °C was detrimental to the maintenance of the Chinese garlic coloration. 

scholarly journals Mathematical Model of Kinetics of Antigens Accumulation in the Process of Periodical Submerged Cultivation of Vibrio cholerae 569В Inaba with Limitation as Regards Carbonic Substrate

2014 ◽  
pp. 96-99
Author(s):  
A. V. Komissarov ◽  
A. K. Nikiforov ◽  
S. N. Zadokhin ◽  
S. A. Eremin ◽  
O. A. Volokh ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Model Comparison ◽  
Initial Conditions ◽  
Accumulation Rate ◽  
Submerged Cultivation ◽  
Maximum Output ◽  
Proposed Model ◽  
Cultivation Process ◽  
Kinetics Of

Presented is mathematical model of kinetics of the process of O-antigen and cholera toxin synthesis during periodical submerged cultivation of V. cholerae 569В Inaba with limitation as regards carbonic substrate. The proposed model is based upon analysis of experimental data on V. cholerae 569В Inaba biomass and antigens accumulation, rate of growth and antigens release, and glucose utilization. Using Mathcad 15.0 software calculated are coefficients of differential equations entering into the mathematical model. Comparison of predicted and experimental data demonstrates that relative error of determination of concentrations of the synthesized substances, glucose and cholera vibrio is between 5 and 20 %. The proposed model permits to determine maximum output of final products and specify the parameters of cultivation process performance at different initial conditions.

scholarly journals Research of kinetics of change in fractional composition of wood raw materials being shredded

2020 ◽  
Author(s):  
Ю.Н. Власов ◽  
Е.В. Нестерова ◽  
Е.Г. Хитров
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Differential Equations ◽  
Fractional Composition ◽  
Raw Materials ◽  
Calculated Data ◽  
General Transformation ◽  
Differential Model ◽  
Integral Differential Equations ◽  
Kinetics Of

В технике при изучении кинетики измельчения материалов пользуются математическими моделями в виде интегро-дифференциальных уравнений, решение которых трудоемко и не всегда приводит к получению наглядных результатов. Цель настоящей статьи разработать математическую модель, раскрывающую кинетику изменения фракционного состава измельчаемых древесных материалов, позволяющую на практике проводить оценку фракционного состава обрабатываемого сырья во времени. Методы исследования математический анализ, численные методы решения дифференциальных уравнений и обработки расчетных данных. Измельчение рассмотрено как многостадийный процесс, при котором фракции материала (узкие классы) под воздействием рабочего органа машины-измельчителя претерпевают превращения, происходящие как последовательно, так и параллельно, причем скорости превращений и доли вновь образованных узких классов материала определяются исходными размерами измельчаемых фракций и параметрами рабочего органа измельчителя. Предложена система дифференциальных уравнений, описывающая в общем превращения узких классов при измельчении, причем коэффициенты уравнений позволяют учесть произвольный вид функций скоростей измельчения фракций и выхода продуктов измельчения. Предложенная система является альтернативой интегро-дифференциальному уравнению балансовой модели измельчения. Выполнена оценка значений параметров математической модели на примере измельчения коры. По результатам сопоставления результатов моделирования с экспериментальными данными, полученными предыдущими исследователями, установлено, что предложенная дифференциальная модель изменения фракционного состава материала при принятых предпосылках к расчету ее параметров качественно и количественно описывает экспериментальных данные с высокой точностью. In techniques at study of kinetics of shredding of materials use mathematical models in the form of the integral-differential equations, which solution is laborious and not always leads to reception of evident results. The purpose of this article is to develop a mathematical model, which reveals the kinetics of change in fractional composition of wood materials being shredded, allowing in practice to evaluate the fractional composition of the processed raw materials in time. Methods of research include mathematical analysis, numerical methods for solving differential equations and processing of calculated data. Shredding is considered as multistage process at which fractions of a material (narrow classes) under the influence of a working body of the shredder machine undergo transformations occurring both consistently and in parallel, and rates of transformations and a share of again formed narrow classes of the material are defined by initial sizes of shredded fractions and parameters of the working body. The system of the differential equations describing in the general transformation of narrow classes at grinding is offered, and factors of the equations allow to consider any kind of functions of speeds of grinding of fractions and the output of shredding products. The proposed system is an alternative to the integral-differential equation of the balance shredding model. The estimation of values of parameters of the mathematical model on an example of bark shredding is carried out. By results of comparison of results of modeling with the experimental data received by previous researchers it is established that the offered differential model of change of fractional composition of the material at the accepted preconditions to calculation of its parameters qualitatively and quantitatively describes the experimental data with high accuracy.

A comparison of turbulent thermal convection between conditions of constant temperature and constant heat flux

2008 ◽  
Vol 595 ◽  
pp. 203-219 ◽  
Author(s):  
R. VERZICCO ◽  
K. R. SREENIVASAN
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Heat Transport ◽  
Constant Temperature ◽  
Thermal Convection ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Experimental Conditions ◽  
Thermal Plumes ◽  
Dimensional Argument

We numerically investigate turbulent thermal convection driven by a horizontal surface of constant heat flux and compare the results with those of constant temperature. Below Ra ≈ 109, where Ra is the Rayleigh number, when the flow is smooth and regular, the heat transport in the two cases is essentially the same. For Ra > 109 the heat transport for imposed heat flux is smaller than that for constant temperature, and is close to experimental data. We provide a simple dimensional argument to indicate that the unsteady emission of thermal plumes renders typical experimental conditions closer to the constant heat flux case.

scholarly journals Mathematical Model of VOCs Emission in Three-layer Building Materials

2021 ◽  
Vol 257 ◽  
pp. 03047
Author(s):  
Zhehua Du ◽  
Xin Lin
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Mathematical Model ◽  
Building Materials ◽  
Present Model ◽  
Transfer Resistance ◽  
Model Predictions ◽  
Layer Resistance ◽  
Boundary Layer Resistance ◽  
Good Agreement

A simple mathematical model is proposed to account for emissions of Volatile Organic Compounds (VOCs) from three-layer building materials. The model considers both the diffusion within three layer building materials and the mass transfer resistance through the air boundary layer. A general solution method based on Laplace transform is presented. Compared to other models capable of accounting for emissions of VOCs from multi layer building materials, the present model is fully analytical instead of being numerical. The present model was validated by the experimental data from the specially designed test. The results indicated that there was a good agreement between the model predictions and the experimental data. It can also be seen from calculation that model ignoring the boundary layer resistance cannot fully reflect the real situation.

Determination of the intensity of polychromatic radiation in the reaction compartment as a function of wavenumber

1991 ◽  
Vol 56 (6) ◽  
pp. 1173-1179 ◽  
Author(s):  
Radim Hrdina ◽  
Igor Čepčiansky ◽  
Hana Bittová
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
High Pressure ◽  
Emission Spectrum ◽  
Photochemical Reactions ◽  
Tabular Form ◽  
Mercury Lamp ◽  
Kinetics Of ◽  
Polychromatic Radiation

A procedure is suggested for studying the kinetics of photochemical reactions using excitation with polychromatic radiation, where the wavenumber dependence of the intensity of the polychromatic radiation entering the reaction compartment must be known. The observed relative intensities of the polychromatic source are calibrated by ferrioxalate actinometry, selected parts of the emission spectrum being eliminated by insertion of filters. The relative intensities of an HBO 200 high-pressure mercury lamp were measured. For the sake of brevity, the experimental data were fitted by a mathematical model (a polynominal), and only the parameters of the polynomial are presented in a tabular form.

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