Kinetics of anaerobic cometabolism of 2,4-dinitrotoluene with ethanol as the primary substrate

1997 ◽  
Vol 36 (6-7) ◽  
pp. 271-278 ◽  
Author(s):  
Jiayang Cheng ◽  
Makram T. Suidan ◽  
Albert D. Venosa
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Competitive Inhibition ◽  
Methanogenic Bacteria ◽  
Experimental Results ◽  
Marquardt Algorithm ◽  
Levenberg Marquardt ◽  
Kinetics Of ◽  
Primary Substrate

A kinetic model that describes the anaerobic cometabolism of 2,4-dinitrtoluene (DNT) with ethanol as the primary substrate has been developed based on experimental results. The kinetic parameters were estimated using the Levenberg-Marquardt algorithm. 2,4-DNT is anaerobically biotransformed to 2,4-diaminotoluene (DAT) via 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) by the bacteria whose growth is supported by utilizing ethanol. 2,4-DNT shows inhibition to its own biotransformation. It also exhibits a very strong competitive inhibition to further biotransformation of 4-A-2-NT and 2-A-4-NT. All the aromatics in the system, 2,4-DNT, 4-A-2-NT, 2-A-4-NT, and 2,4-DAT, inhibit the conversion of ethanol. Hydrogen produced from the acetogenesis of ethanol is utilized for the transformation of the nitroaromatics. The utilization of hydrogen and acetate by methanogenic bacteria is very strongly inhibited by the presence of the nitroaromatics. Acetate exhibits strong competitive inhibition to the biodegradation of propionate.

Kinetics and Modelling of Bulk and Solution Diallyl Terephthalate Polymerization

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Iztok Hace
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Rate Constants ◽  
Chain Transfer ◽  
Average Molecular Weight ◽  
Propagation Rate ◽  
Reaction Conditions ◽  
Diffusion Limitations ◽  
Kinetics Of ◽  
Dicyclohexyl Peroxydicarbonate

Free radical polymerization kinetics of diallyl terephthalate (DAT) in solution was investigated with two different peroxide initiators: dicyclohexyl peroxydicarbonate (CHPC) and benzoyl peroxide (BPO) in temperature range from 50°C to 110°C, where ortho-xylene was used as a solvent. Conversion points were measured using Fourier Transform Infrared (FTIR) measurements. Previously developed kinetic model for bulk DAT polymerization, was extended to solution DAT polymerization. The ratio of solvent chain - transfer rate constants to propagation rate constants of the polymerization system were found between 1.25 10-4 to 1.68 10-4 for various reaction conditions. They were obtained using the calculated initial polymerization rates and the number average molecular weight measurements made by GPC. The effect of different solvent fractions and initiator concentrations on the diffusion limitations were investigated. Only two kinetic parameters, kpd0 and ktd0 were obtained by fitting the kinetic model onto measured conversions for various reaction conditions at 0.2, 0.5 and 0.8 solvent fractions. Thus obtained kpd0 and ktd0 kinetic parameters were extrapolated to zero solvent fractions and from obtained values of kinetic parameters the conversion points for bulk DAT polymerization were calculated and compared to measured conversion points.

DEVELOPING OF MATLAB APPLICATION FOR DETERMINING THE REACTION KINETICS OF RUBBER VULCANIZATION PROCESS

2021 ◽  
Author(s):  
Dario Balaban ◽  
◽  
Jelena Lubura ◽  
Predrag Kojić ◽  
Jelena Pavličević ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Reaction Kinetics ◽  
Kinetic Parameters ◽  
Degradation Process ◽  
Complex Process ◽  
Quality Of Fit ◽  
Kinetics Of ◽  
Vulcanization Process

Rubber vulcanization is kinetically a complex process, since it consists of two simultaneous reactions: curing and degradation. To determine reaction kinetics, it is necessary to determine a kinetic model which describes the process adequately. Proposed kinetic model has six adjustable parameters. In order to determine kinetic parameters of the proposed kinetic model, commercially available rubber gum was used. Oscillating disc rheometer was used to investigate experimental dependence of torque on time, at six temperatures in the range from 130 to 180 °C, with a step of 10 °C. Matlab application, built via App Designer feature, was developed in order to fit the experimental data to the proposed kinetic model. Developed Matlab application, consisting of two tabs, enables user to upload raw rheometer data, perform manual fitting or automatic fitting (manual or automatic estimation of initial values of adjustable parameters), test the effect of constant values of some kinetic parameters on the overall quality of fit, visualize the dependence of kinetic parameters on temperature and to determine the values of Arrhenius expression for curing and degradation process. Both fitting methods were proven to be efficient; overall determination coefficient and MAPE value for automatic and manual fitting methods were >0.99 and <1%, and >0.999 and <1%, respectively. Arrhenius parameters were also determined with high accuracy (R2>0.98). Developed application enables simple and efficient determination of kinetic parameters by means of different fitting methods, simultaneous fitting of data on all temperatures, and testing the effect of constant kinetic parameters values on fitting results

Development of an Activity Based Kinetic Model for an Esterification Process with Indion 180 Catalyst

2019 ◽  
Vol 17 (9) ◽  
Author(s):  
Mekala Mallaiah ◽  
Chimmiri Venkateswarlu
Keyword(s):  
Kinetic Model ◽  
Reaction Rate ◽  
Experimental Results ◽  
Catalyst Loading ◽  
Esterification Reaction ◽  
Order Kinetic ◽  
Kinetic Rate ◽  
Model Predictions ◽  
Effects Of Temperature ◽  
Kinetics Of

Abstract The kinetics of esterification reaction between acetic acid and methanol was studied with the Indion 180 catalyst in the temperature range between 323.15 and 353.15K, and the catalyst loading between 0.01 g/cc to0.05 g/cc. The effects of temperature, catalyst loading, size of the catalyst and agitation speed on the reaction rate were investigated. The experimental results have shown the negligible effect of mass transfer resistances on the reaction rate. A second order kinetic rate expression was used to correlate the experimental data. An activity based kinetic model was also developed for the esterification process, which was validated against experimental results. The activity based model is found advantageous as it involves only two reaction rate parameters which were determined based on the kinetic rate parameters of the concentration based model. The comparison of the model predictions with the experimental results for different temperature and catalyst loading conditions has shown the better suitability of the activity based kinetic model for the esterification process with Indion 180 catalyst.

Kinetics of Thermal Degradation of Ionic Liquid Regenerated Cellulose

2012 ◽  
Vol 488-489 ◽  
pp. 923-927
Author(s):  
Nawshad Muhammad ◽  
Zakaria B. Man ◽  
M. Azmi Bustam Khalil ◽  
Sikander Rafiq
Keyword(s):  
Activation Energy ◽  
Ionic Liquid ◽  
Kinetic Model ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Dynamic Condition ◽  
Degradation Process ◽  
Waste Paper ◽  
Regenerated Cellulose ◽  
Kinetics Of

In the present work ionic liquid has been used for the regeneration of cellulose from waste writing paper. The regenerated cellulose was characterized by TGA, FTIR and XRD analyses. Kinetics of thermal degradation of this cellulose was carried out under dynamic condition using thermogravimetry. Coats-Redfern kinetic model was used to determine the kinetic parameters for the degradation process. The activation energy for the thermal degradation of the regenerated cellulose has been found to be less than the precursor waste paper.

Research on the Prediction of Drug Sales Based on Levenberg-Marquardt Algorithm

2012 ◽  
Vol 198-199 ◽  
pp. 1452-1456 ◽  
Author(s):  
Xue Feng Jiang
Keyword(s):  
Neural Network ◽  
Prediction Model ◽  
Production Planning ◽  
Bp Neural Network ◽  
Bp Algorithm ◽  
Experimental Results ◽  
Drug Production ◽  
Drug Sales ◽  
Marquardt Algorithm ◽  
Levenberg Marquardt

Prediction of drug sales trend is very important for the drug production planning and inventory. The paper studies the BP neural network and presents a kind of method based on reformative neural network to solve the issue of prediction of drug sales. Compare with traditional BP algorithm, the result reveals that this algorithm has structure rationalization and rapid constringency velocity. The experimental results demonstrate that the prediction model based on Levenberg_Marquardt algorithm is good at predicting drug sales.

Robust and Efficient Solution to Absolute Orientation in Low-Altitude Photogrammetry

2014 ◽  
Vol 631-632 ◽  
pp. 456-461
Author(s):  
Hai Qing He ◽  
Peng Gen Cheng
Keyword(s):  
Coordinate System ◽  
Efficient Solution ◽  
Experimental Results ◽  
Coordinate Systems ◽  
Absolute Orientation ◽  
Aerial Triangulation ◽  
Marquardt Algorithm ◽  
Levenberg Marquardt ◽  
Low Altitude

Absolute orientation is a classic photogrammetric task for recovering the transformation relationship between two coordinate systems. In low-altitude photogrammetric field, arbitrary coordinate system in the network of aerial triangulation is spatial auxiliary coordinate system, which is quite different from ground photogrammetric coordinate. So the commonly used solution to absolute orientation with simplified parameters is unsuitable for low-altitude photogrammetry. In this paper, a novel solution of absolute orientation is proposed, the initial parameters of absolute orientation can be solved by the formula using centroids of coordinates instead of simplified parameters, then the parameters of absolute orientation are iteratively refined by Levenberg-Marquardt algorithm. Experimental results show that the solution is effective and practical. It may be suitable to implement absolute orientation in low-altitude photogrammetry.

scholarly journals Dual-Cycle Mechanism Based Kinetic Model for DME-to-Olefin Synthesis on HZSM-5-Type Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1459
Author(s):  
Maria Magomedova ◽  
Anastasiya Starozhitskaya ◽  
Ilya Davidov ◽  
Anton Maximov ◽  
Maksim Kravtsov
Keyword(s):  
Kinetic Model ◽  
Kinetic Parameters ◽  
Reaction Pathways ◽  
Software Environment ◽  
Olefin Synthesis ◽  
Leading Role ◽  
Marquardt Algorithm ◽  
Dual Cycle ◽  
Synthesis Routes

A kinetic model for the olefins synthesis from dimethyl ether on zeolite HZSM‑5 based catalysts is developed. The model includes the reaction pathways for the synthesis of olefins from oxygenates in the olefinic and aromatic cycles according to modern concepts of the dual-cycle reaction mechanism. The kinetic parameters were determined for the time-stable hydrothermally treated catalysts of various activities Mg-HZSM-5/Al2O3, HZSM-5/Al2O3, and Zr-HZSM-5/Al2O3. The kinetic parameters determination and the solution of the ordinary differential equations system were carried out in the Python software environment. The preliminary estimation of the kinetic parameters was carried out using the Levenberg-Marquardt algorithm, and the parameters were refined using the genetic algorithm. It is shown that reactions activation energies for different catalysts are close, which indicates that the priority of the reaction paths on the studied catalysts is the same. Thus, the topology of the zeolite plays a leading role in the determination of the synthesis routes, rather than the nature of the modifying metal. The developed model fits the experimental data obtained in an isothermal reactor in the range of temperature 320–360 °C, specified contact time 0.1–3.6 h*gcat/gC with a relative error of less than 15%.

Kinetics of thermal degradation of wood biomass

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Ivan Hrablay ◽  
Ľudovít Jelemenský
Keyword(s):  
Kinetic Parameters ◽  
13C Nmr ◽  
Model Fitting ◽  
Isoconversional Method ◽  
Experimental Results ◽  
Pyrolysis Kinetics ◽  
Exponential Factor ◽  
Model Free ◽  
Fitting Method ◽  
Kinetics Of

AbstractPyrolysis kinetics of a hardwood representative, beech (Fagus sylvatica), was investigated by two different kinetic approaches: model-free isoconversional method and model-fitting method. The model-free isoconversional method was used for the determination of apparent kinetic parameters, i.e. the activation energy and pre-exponential factor. The model fitting method was used for the optimization of kinetic parameters of the reaction pathways of three selected reaction mechanisms: one-step, two-step, and three-step one. In both approaches, thermo-gravimetric data were used at five heating rates: 2°C min−1, 5°C min−1, 10°C min−1, 15°C min−1 and 20°C min−1. As the most suitable mechanism, the three-step mechanism containing the intermediate degradation step was chosen. This selection was supported by experimental results from the 13C NMR analysis of solid residues prepared at the key temperatures within the range of 230–500°C. The progress of mass fraction values of each component in this mechanism was simulated. Conclusions from the simulation were confronted with experimental results from the 13C NMR.

Kinetic Aspects of the Interaction of Blood Clotting Enzymes

1968 ◽  
Vol 19 (03/04) ◽  
pp. 364-367 ◽  
Author(s):  
H. C Hemker ◽  
P. W Hemker
Keyword(s):  
Enzyme Kinetics ◽  
Blood Clotting ◽  
Competitive Inhibition ◽  
Competitive Inhibitor ◽  
Kinetics Of

SummaryThe enzyme kinetics of competitive inhibition under conditions prevailing in clotting tests are developed and a method is given to measure relative amounts of a competitive inhibitor by means of the t — D plot.

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