“Best values” of Michaelis-Menten kinetic constants from experimental data

1968 ◽  
Vol 22 (3) ◽  
pp. 549-552 ◽  
Author(s):  
Stephen R. Cohen
Keyword(s):  
Experimental Data ◽  
Kinetic Constants ◽  
Menten Kinetic

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

Realization of Detailed Kinetic Models for the Growth of II-VI Compounds: Adopting DFT Calculations and Experimental Evidences

1999 ◽  
Vol 584 ◽  
Author(s):  
Carlo Cavallotti ◽  
Valeria Bertani ◽  
Maurizio Masi ◽  
Sergio Carrà
Keyword(s):  
Experimental Data ◽  
Kinetic Theory ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Kinetic Scheme ◽  
Kinetic Constants ◽  
Surface Processes ◽  
Gas Phase Reactions ◽  
Elementary Reactions ◽  
Kinetics Of

AbstractThe kinetics of deposition of CdTe, ZnS and ZnSe films was studied. An overall microkinetically reversible kinetic scheme consisting of elementary reactions, comprehensive of gas phase and surface processes was developed. Kinetic constants of gas phase reactions were either found in the literature or determined through quantum chemistry methods. Kinetic constants of surface reactions were first guessed combining kinetic theory with quantum chemical calculations and then their values were refined to reproduce experimental data. The kinetics schemes so developed were tested through the simulation of deposition reactors. Measured growth rates and gas phase compositions were thus compared with those calculated. The major finding of this studies is that the growth of CdTe, ZnS and ZnSe can be represented adopting a surface kinetic scheme constituted essentially by the same fundamental steps.

Combustion in Ni–Al system with Cu additive (powder or rod) Experiment and mathematical model

2020 ◽  
pp. 33-43
Author(s):  
O. V. Lapshin ◽  
A. M. Shul’pekov ◽  
R. M. Gabbasov ◽  
V. D. Kitler
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Relative Density ◽  
Aluminum Matrix ◽  
Kinetic Constants ◽  
Model Parameters ◽  
Nickel Aluminum ◽  
Copper Melt ◽  
Analytical Formulas ◽  
The Mathematical Model

Experimental studies were carried out with theoretical calculations of wave synthesis in the Ni–Al–Cu system were performed using the mathematical model developed. Approximate analytical formulas were obtained for synthesis performance evaluation. The inverse problem method was used to get kinetic constants that determine process dynamics based on the experimental data and analytical relationships. It is shown that the combustion front propagation velocity increases monotonically with an increase in the reaction sample relative density in the range of relative density values of 0.4 to 0.6. The depth of copper melt penetration from the center of the sample into the nickel-aluminum matrix depends on the relative density of the sample and copper wire diameter: higher densities and larger diameters lead to an increase in the liquid-phase impregnation area. The rate of nickel and aluminum powder frame wetting with copper melt is limited by the synthesis wave speed. Based on the experimental data and analytical ratios, we estimated the effective kinetic constants describing the high-temperature synthesis of the Ni + Al reaction mixture in the presence of copper additives. The thermal effect of the NiAl intermetallic formation reaction and the preexponential factor in the chemical transformation equation are calculated, the exponent value in the ratio for the mixture thermal conductivity is established; a constant determining the process of nickel-aluminum matrix impregnation with copper melt is found. The macroscopic approach used to analyze the NiAl intermetallic synthesis makes it possible to determine all the desired physicochemical characteristics and model parameters. The mathematical model is suitable for predictive estimates and experimental data analysis in the macroscopic approximation. Approximate analytical formulas are obtained for calculating the NiAl intermetallic synthesis characteristics. They allow for calculating the through channel characteristics and can be used in the design of NiAl products.

scholarly journals A Heterothermic Kinetic Model of Hydrogen Absorption in Metals with Subsurface Transport

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1131 ◽  
Author(s):  
Ono ◽  
Uchikoshi ◽  
Hayashi ◽  
Kitagawa ◽  
Yeh ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Parameters ◽  
Hydrogen Absorption ◽  
Hydrogen Adsorption ◽  
Bulk Diffusion ◽  
Operating Conditions ◽  
Calculation Scheme ◽  
Kinetic Constants ◽  
Absorption Process ◽  
Subsurface Transport

A versatile numerical model for hydrogen absorption into metals was developed. Our model addresses the kinetics of surface adsorption, subsurface transport (which plays an important role for metals with active surfaces), and bulk diffusion processes. This model can allow researchers to perform simulations for various conditions, such as different material species, dimensions, structures, and operating conditions. Furthermore, our calculation scheme reflects the relationship between the temperature changes in metals caused by the heat of adsorption and absorption and the temperature-dependent kinetic parameters for simulation precision purposes. We demonstrated the numerical fitting of the experimental data for various Pd temperatures and sizes, with a single set of kinetic parameters, to determine the unknown kinetic constants. Using the developed model and determined kinetic constants, the transitions of the rate-determining steps on the conditions of metal-hydrogen systems are systematically analyzed. Conventionally, the temperature change of metals during hydrogen adsorption and absorption has not been a favorable phenomenon because it can cause errors when numerically estimating the hydrogen absorption rates. However, by our calculation scheme, the experimental data obtained under temperature changing conditions can be positively used for parameter fitting to efficiently and accurately determine the kinetic constants of the absorption process, even from a small number of experimental runs. In addition, we defined an effectiveness factor as the ratio between the actual absorption rate and the virtually calculated non-bulk-diffusion-controlled rate, to evaluate the quantitative influence of each individual transport process on the overall absorption process. Our model and calculation scheme may be a useful tool for designing high-performance hydrogen storage systems.

A Kinetic Model for Translocators in the Chloroplast Envelope as an Element of Computersimulation of the Dark Reaction of Photosynthesis

1977 ◽  
Vol 32 (3-4) ◽  
pp. 263-270 ◽  
Author(s):  
Christoph Giersch
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Kinetic Model ◽  
Arbitrary Number ◽  
External Medium ◽  
Kinetic Constants ◽  
Chloroplast Envelope ◽  
Dark Reaction ◽  
Phosphate Translocator ◽  
Minimum Number

Abstract A kinetic model for the chloroplast translocators (mediating equal and opposite exchange fluxes between the external medium and the stroma) is derived. This model is a modification of the classical Widdas model corresponding to the exchange of an arbitrary number of compounds with no contribution to net transport. It describes the rate of transport of each compound in simple terms and with a minimum number of kinetic constants. Predictions from the model agree with experimental data as recorded in the literature. From the experimental apparent kinetic constants VMAX and Km those in terms of the model are calculated. These constants complete the model and make it applicable to the study of metabo­lism of photosynthesis by means of computer simulation. The set of differential equations describing the operation of the phosphate translocator is solved numerically for some illustrative examples.

Kinetic model for S-TBBS-DPG NR vulcanization: Extrapolation from S-TBBS and S-DPG experimental data

2016 ◽  
Vol 15 (08) ◽  
pp. 1650068 ◽  
Author(s):  
Gabriele Milani ◽  
Federico Milani
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Kinetic Constants ◽  
Experimental Investigations ◽  
Trial And Error ◽  
Crosslinked Polymer ◽  
Extrapolation Model ◽  
Two Temperatures ◽  
Error Optimization ◽  
Good Agreement

A robust extrapolation model requiring few input parameters to predict the kinetic constants characterizing the curing behavior of NR vulcanized in presence of sulfur and two accelerants (TBSS and DPG) at different concentrations is discussed. The numerical model based on the reproduction of rheometer curves by means of the well-known Han’s kinetic model, which describes with kinetic base the most important NR vulcanization phases, namely curing initiation, formation of matured crosslinked polymer and reversion. The derived mathematical model is a closed form exponential function depending on only three kinetic constants. The procedure proposed is a two-step one. In the first step, kinetic constants of NR in the presence of single activators (i.e. either only with S and TBBS or S and DPG) are estimated by means of an interactive trial and error optimization software (GURU) that proceeds in approximating more and more strictly normalized experimental rheometer curves with Han’s function. Four different concentrations of S and TBSS (or S and DPG) are assumed as calibration points. In the second step, from the results obtained previously, kinetic constants for NR with any S-TBBS-DPG concentration of technical relevance are deduced by means of standard mathematical extrapolation. The procedure is benchmarked on 16 different S-TBBS-DPG concentrations at two temperatures (150[Formula: see text]C and 180[Formula: see text]C), for which both experimental data are available and kinetic constants are previously derived with GURU. Quite good agreement is found, meaning that the approach may be useful for practical purposes, because expensive and cumbersome experimental investigations can be avoided.

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