Kinetics modelling

Bài giảng Xúc tác - Chương 4: Động học phản ứng xúc tác (Kinetics of catalytic reactions). Chương này cung cấp cho học viên những nội dung gồm: giới thiệu; nồng độ trên bề mặt của chất bị hấp phụ; các mô hình (model) phản ứng trên xúc tác rắn; cách xây dựng phương trình tốc độ;... Mời các bạn cùng tham khảo!

11p mothuahoa 04-05-2024 6 2   Download

This thesis derives closed form equations to describe electromagnetic device characteristics for a toroid, solenoid and a case study induction machine. By considering stored magnetic field energy, this approach allows the relationship between electrical, magnetic and kinetic energy to be quantified and analyzed in ways that allows improved accuracy compared with conventional magnetic circuit modeling methods. This thesis also provides insights into how geometric parameters impact energy transfer and operational characteristics of electromagnetic devices.

112p runthenight04 02-02-2023 18 2   Download

Building a model, setting up a system of dynamic equations of the circular saw cutting bamboo, solving the dynamic equations, from which to calculate and determine some reasonable kinetic and dynamic parameters of the circular saw to improve productivity and cutting surface quality

26p closefriend09 16-11-2021 15 5   Download

These studies are performed in the general framework of transient coupled calculations with accurate neutron kinetics models. This kind of application requires a modeling of the influence on the neutronics of the macroscopic cross-section evolution.

8p christabelhuynh 30-05-2020 5 1   Download

The studies presented in this paper are performed in the general framework of transient coupled calculations with accurate neutron kinetics models able to characterize spatial decoupling in the core. An innovative fission matrix interpolation model has been developed with a correlated sampling technique associated to the Transient Fission Matrix (TFM) approach.

14p christabelhuynh 30-05-2020 8 0   Download

Kinetic study of oxidation of toluidine blue (TB+) by periodate was carried out in aqueous medium and also in the cetyl trimethyl ammonium bromide (CTAB) reverse micellar medium. In both the media reaction obeys first order kinetics with respect to each of the reactants.

8p tocectocec 25-05-2020 10 2   Download

Hepcidin (H25) is a hormone peptide synthesized by the liver that binds to ferroportin and blocks iron export. In this study, H25 was inhibited by administration of single and multiple doses of an anti-H25 monoclonal antibody Ab 12B9m in cynomolgus monkeys. The objective of this analysis was to develop a pharmacodynamic model describing the role of H25 in regulating iron homeostasis and the impact of hepcidin inhibition by Ab 12B9m. Total serum H25 and Ab 12B9m were determined in each animal. Corresponding measurements of serum iron and hemoglobin (Hb) were obtained.

15p caothientrangnguyen 09-05-2020 13 1   Download

The objective of the thesis is to propose some new control methods to compensate for the negative effects of pattern uncertainty, external noise and wheel slip. Analyze and build dynamic and kinetic models of mobile robots when model uncertainties exist. Demonstrating the correctness and effectiveness of new control methods by the Lyapunov stability standard and Barbalat lemma. Advanced domestic and foreign control methods for mobile robots in the presence of uncertainty models, external noise, and wheel slip. Then propose new control methods.

26p xacxuoc4321 09-07-2019 42 3   Download

Objectives of thesis: Study on phenol treatment in water by ozonation process combined with catalysts. An empirical kinetic model and one quadratic regression equations were built based on experimental data for destroying phenol by heterogeneous catalytic ozonation process with response variables (initial pH, ozone concentration, catalyst concentration and reaction time). Application of phenol treatment in coking wastewater.

29p xacxuoc4321 08-07-2019 20 4   Download

The design of b-glycosidases with planed substrate specificity for biotechnological application has received little attention. This is mostly a consequence of the lack of data on the molecular basis of the b-glycosidase specificity, namely data on the energy of the noncovalent interactions in the enzymetransition state complex. In an attempt to fill this gap, sitedirected mutagenesis and enzyme steady-state kinetic experiments with different substrates were conducted, using as model a digestive b-glycosidase (glycoside hydrolase family 1) from Spodoptera frugiperda (Lepidoptera) (Sfbgly50).

10p system191 01-06-2013 47 4   Download

Many biological C-H activation reactions exhibit nonclassical kinetic isotope effects (KIEs). These nonclassical KIEs are too large (kH/kD 7) and/or exhibit unusual temperature dependence such that the Arrhenius prefactor KIEs (AH/AD) fall outside of the semiclassical range near unity. The focus of this minireview is to discuss such KIEs within the context of the environmentally coupled hydrogen tunneling model.

9p system191 01-06-2013 38 4   Download

A comparative study of thermodynamic and kinetic aspects of Cu(II) and Ni(II) binding at the N-terminal binding site of human and bovine serum albumins (HSA and BSA, respectively) and short peptide analogues was performed using potentiometry and spectroscopic techniques. It was found that while qualitative aspects of interaction (spectra and structures of complexes, order of reactions) could be reproduced, the quantitative parameters (stability and rate constants) could not.

9p research12 01-06-2013 43 4   Download

This paper describes violaxanthin de-epoxidation in model lipid bilayers. Unilamellar egg yolk phosphatidylcholine (PtdCho) vesicles supplemented with monogalactosyldi-acylglycerol were found to be a suitable system for studying this reaction. Such a system resembles more the native thylakoid membrane and offers better possibilities for studying kinetics and factors controlling de-epoxidation of violaxanthin than a systemcomposed only of monogalacto-syldiacylglycerol and is commonly used in xanthophyll cycle studies. ...

10p research12 23-04-2013 31 3   Download

Mature, active mammalian histidine decarboxylase is a di-meric enzyme of carboxy-truncatedmonomers (
53 kDa). By using a biocomputational approach, we have generateda three-dimensional model of a recombinant 1/512 fragment of the rat enzyme, which shows kinetic constants similar to those of the mature enzyme purified from rodent tissues. This model, together with previous spectroscopic data, al-lowed us to postulate that the occupation of the catalytic center by the natural substrate, or by substrate-analogs, would induce remarkable changes in the conformation of the intact holoenzyme....

12p tumor12 20-04-2013 37 2   Download

Although alkaline phosphatase (APase) fromEscherichia colicrystallizes as a symmetric dimer, it displays deviations from Michaelis–Menten kinetics, supported by a model describing a dimeric enzyme with unequal subunits [Orha-novic´ S., Pavela-Vrancˇicˇ M. and Flogel-Mrsˇic´ M. (1994) Acta. Pharm.44, 87–95]. The possibility, that the observed asymmetry could be attributed to negative cooperativity in Mg2+ binding, has been examined. The influence of the metal ion content on the catalytic properties of APase from E. colihas been examined by kinetic analyses. ...

9p tumor12 20-04-2013 46 3   Download

In this article, we report the results of an analysis of the glycolytic enzyme enolase (2-phospho-D-glycerate hydro-lase) of Trypanosoma brucei. Enolase activity was detected in both bloodstream-form and procyclic insect-stage try-panosomes, although a 4.5-fold lower specific activity was found in the cultured procyclic homogenate. Subcellular localization analysis showed that the enzyme is only pre-sent in the cytosol.

9p tumor12 20-04-2013 30 3   Download

We report experiments to investigate the role of the physio-logically relevant protein tyrosine kinase Lck in the ordered phosphorylation of the T-cell receptorfchain. Six synthetic peptides were designed based on the sequences of the immunoreceptor tyrosine-based activation motifs (ITAMs) of thefchain. Preliminary 1 H-NMRstudies of recombinant f chain suggested that it is essentially unstructured and therefore that peptide mimics would serve as useful models for investigating individual ITAM tyrosines....

8p fptmusic 16-04-2013 28 1   Download

This work proposes a model of the metabolic branch-point between the methionine and threonine biosynthesis path-ways inArabidopsis thalianawhich involves kinetic compe-tition for phosphohomoserine between the allosteric enzyme threonine synthase and the two-substrate enzyme cysta-thionine c-synthase. Threonine synthase is activated by S-adenosylmethionine and inhibited by AMP. Cystathio-ninec-synthase condenses phosphohomoserine to cysteine via a ping-pong mechanism.

13p fptmusic 12-04-2013 43 3   Download

Fructose 2,6-bisphosphate is a potent allosteric activator of trypanosomatid pyruvate kinase and thus represents an important regulator of energy meta-bolism in these protozoan parasites. A 6-phosphofructo-2-kinase, respon-sible for the synthesis of this regulator, was highly purified from the bloodstream form ofTrypanosoma bruceiand kinetically characterized. By searching trypanosomatid genome databases, four genes encoding proteins homologous to the mammalian bifunctional enzyme 6-phosphofructo-2-kinase⁄fructose-2,6-bisphosphatase (PFK-2⁄FBPase-2) were found for both T. ...

19p fptmusic 11-04-2013 34 3   Download

The glyoxalase pathway ofLeishmania infantumwas kinetically character-ized as a trypanothione-dependent system. Using time course analysis based on parameter fitting with a genetic algorithm, kinetic parameters were estimated for both enzymes, with trypanothione derived substrates. A Kmof 0.253 mmand aVof 0.21lmolÆmin )1 Æmg )1 for glyoxalase I, and a Kmof 0.098 mmand aVof 0.18lmolÆmin )1 Æmg )1 for glyoxalase II, were obtained.

11p awards 06-04-2013 46 2   Download