Critical Analysis of Kinetic Modeling Procedures

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
José Carlos Pinto ◽  
Marcos W. Lobao ◽  
Andre L. Alberton ◽  
Marcio Schwaab ◽  
Marcelo Embiruçu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Reaction Mechanisms ◽  
Critical Analysis ◽  
Kinetic Data ◽  
Statistical Analyses ◽  
Statistical Tools ◽  
Combinatorial Explosion ◽  
Kinetic Rate ◽  
Rate Determining Steps

In this work, issues related to the mathematical modeling and statistical analyses of kinetic data are discussed. Firstly, problems related to the combinatorial explosion of the number of plausible kinetic models are analyzed, when complex reaction mechanisms are taken into consideration and distinct rate determining steps are assumed. Although modeling procedures based on rate-determining steps can lead to oversimplification of kinetic models, these procedures are still very popular because the existence of multiple rate-determining steps usually renders the analytical derivation of kinetic rate expressions impossible. However, if the derived kinetic models are too simple, one can face serious difficulties to fit the proposed models to available experimental data. Secondly, problems related to the statistical analyses of experimental data are discussed. Particularly, very often statistical tools are used even when some of the fundamental assumptions required for their validity are violated. For this reason, the fundamental grounds that support some of the most popular statistical tools are discussed in the framework of the kinetic analysis.

Development of Predictive Structure-Biodegradation Relationship Models with the Use of Respirometrically Generated Biokinetic Data

1992 ◽  
Vol 26 (3-4) ◽  
pp. 763-772 ◽  
Author(s):  
H. H. Tabak ◽  
C. Gao ◽  
S. Desai ◽  
R. Govind
Keyword(s):  
Experimental Data ◽  
Aquatic Environment ◽  
Kinetic Data ◽  
Additional Data ◽  
Group Contribution ◽  
Monod Kinetics ◽  
Kinetic Rate ◽  
First Order ◽  
Kinetic Rate Constants ◽  
Monod Kinetic

Biodegradation is an important mechanism determining the fate of chemicals in the aquatic environment. In this paper, experimental data, determined from electrolytic respirometry, for 27 compounds were analyzed using first order and Monod kinetics. Additional data from the literature were also used in our analysis. A method based on group contribution to predict first-order and Monod kinetic rate constants was developed and validated. The group contribution approach gave reasonable results for a variety of compounds. More kinetic data are required to extend the group contribution approach.

A New Adsorption Rate Equation in Batch Systems

2018 ◽  
Author(s):  
yongson hong ◽  
Kye-Ryong Sin ◽  
Jong-Su Pak ◽  
Chol-Min Pak
Keyword(s):  
Experimental Data ◽  
Kinetic Analysis ◽  
Adsorption Kinetics ◽  
Rate Equation ◽  
Kinetic Models ◽  
Adsorption Kinetic ◽  
Adsorption Rate ◽  
Batch Systems ◽  
New View

<p><b>In this paper, the deficiencies and cause of previous adsorption kinetic models were revealed, new adsorption rate equation has been proposed and its validities were verified by kinetic analysis of various experimental data.</b> <b>This work is a new view on the adsorption kinetics rather than a comment on the previous adsorption papers.</b></p>

scholarly journals Kinetics study on non-isothermal thermochemical liquefaction of corncobs in ethanol-water solution: Effect of ethanol concentration

2018 ◽  
Vol 197 ◽  
pp. 09005
Author(s):  
Bregas Siswahjono Tatag Sembodo ◽  
Hary Sulistyo ◽  
Wahyudi Budi Sediawan ◽  
Mohammad Fahrurrozi
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Ethanol Concentration ◽  
Water Solution ◽  
Reaction Products ◽  
Gaseous Products ◽  
Bio Oil ◽  
Volatile Products ◽  
Calculation Results ◽  
Oil Gas

Corncobs are potentially processed into bio-oil through thermochemical liquefaction processes. It is difficult to construct kinetics models based on the compounds involved in the reaction. It would be made four kinetic models based on four reaction products, i.e., solids, bio-oil, gas and volatile products. The purposes of the study were to seek kinetics model of thermochemical liquefaction of corncobs in ethanol-water solution and to study the effect of ethanol concentration. The experiment of liquefaction processes of corncobs in ethanol-water solution using sodium carbonate catalyst was performed in the 150 ml autoclave equipped with a magnetic stirrer in the temperature up to 280°C. Four kinetic models were applied to predict the yield of four reaction product lumps. The calculation results were compared to the experimental data. Compared to the others, model 4 was the most realistic and closely matching to the experimental data. In model 4 the reaction mechanism was assumed that biomass (corncobs) first decomposed into bio-oil, followed by decomposition of bio-oil into volatile products reversibly and, finally, volatile products decomposed into gaseous products. The yield of bio-oil increased from 42.05% to 54.93% by increasing to ethanol concentration of 0% to 40%.

Kinetics of Hydrogen Absorption, Desorption And Permeation of Metals

CORROSION ◽  
1958 ◽  
Vol 14 (12) ◽  
pp. 34-38 ◽  
Author(s):  
T. G. OWE BERG
Keyword(s):  
Experimental Data ◽  
Reaction Mechanisms ◽  
Hydrogen Absorption ◽  
Hydrogen Gas ◽  
Acid Solutions ◽  
Dilute Acid ◽  
Energy Diffusion ◽  
Dissolved Hydrogen ◽  
Kinetics Of ◽  
Absorption Of Hydrogen

Abstract The reaction mechanisms for the absorption of hydrogen by metals from moist hydrogen gas and dilute acid solutions, for the desorption from metals of dissolved hydrogen in the presence of water and for hydrogen solubility and permeation under those conditions are discussed. Their kinetics are also given. Formulae are derived for rates and equilibria. These are compared with experimental data. The migration of H atoms in the metal is concluded to be associated with zero or nearly zero activation energy. Diffusion is rapid enough to maintain almost uniform distribution of H atoms in the metal during absorption and desorption under ordinary conditions. 3.8.4

scholarly journals Complications of Uterine Fibroids and Their Management, Surgical Management of Fibroids, Laparoscopy and Hysteroscopy versus Hysterectomy, Haemorrhage, Adhesions, and Complications

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Liselotte Mettler ◽  
Thoralf Schollmeyer ◽  
Andrea Tinelli ◽  
Antonio Malvasi ◽  
Ibrahim Alkatout
Keyword(s):  
Surgical Treatment ◽  
Surgical Management ◽  
Critical Analysis ◽  
Severe Pain ◽  
Uterine Fibroids ◽  
Statistical Analyses ◽  
Hysteroscopic Myomectomy

A critical analysis of the surgical treatment of fibroids compares all available techniques of myomectomy. Different statistical analyses reveal the advantages of the laparoscopic and hysteroscopic approach. Complications can arise from the location of the fibroids. They range from intermittent bleedings to continuous bleedings over several weeks, from single pain episodes to severe pain, from dysuria and constipation to chronic bladder and bowel spasms. Very seldom does peritonitis occur. Infertility may result from continuous metro and menorrhagia. The difficulty of the laparoscopic and hysteroscopic myomectomy lies in achieving satisfactory haemostasis using the appropriate sutures. The hysteroscopic myomectomy requires an operative hysteroscope and a well-experienced gynaecologic surgeon.

Catalytic upgrading of ethanol to n-butanol using an aliphatic Mn–PNP complex: theoretical insights into reaction mechanisms and product selectivity

2019 ◽  
Vol 9 (11) ◽  
pp. 2794-2805 ◽  
Author(s):  
Kuber Singh Rawat ◽  
Shyama Charan Mandal ◽  
Preeti Bhauriyal ◽  
Priyanka Garg ◽  
Biswarup Pathak
Keyword(s):  
Reaction Mechanisms ◽  
Product Selectivity ◽  
Catalytic Upgrading ◽  
Rate Determining Steps

Understanding the product selectivity, conversion, and rate-determining steps in the catalytic upgrading of ethanol to butanol.

scholarly journals Study of the inhibitory ability of inorganic di- and polyphosphate compositions

2020 ◽  
Vol 315 ◽  
pp. 04002
Author(s):  
Aktoty Niyazbekova ◽  
Timur Shakirov ◽  
Mayra Almagambetova
Keyword(s):  
Experimental Data ◽  
Kinetic Data ◽  
Research Work ◽  
Corrosion Process ◽  
Degree Of Protection ◽  
Inhibitory Ability ◽  
Depth Index ◽  
Corrosion Deposits ◽  
The Stability ◽  
Quantitative Indicators

The article considers the anticorrosive properties of inorganic di-and polyphosphate compositions in relation to St-3 steel, depending on the pH of the medium, the nature and concentration of phosphate, and the nature of the modifier ion. The research was conducted using GOST-based methods: gravimetry, potentiometry, photocolorimetry, infrared spectroscopy and scanning electron microscopy. On the basis of experimental data, quantitative indicators of corrosion process were determined: the rate of corrosion process, the degree of protection, the depth index, the coefficient of inhibition and the assessment of the stability of the formed film on the ball scale of corrosion resistance against steel. The analysis of experimental data allows to establish the influence of the above factors on the corrosion processes in the systems under study. The experimental data are supplemented by thermodynamic calculations of the corrosion process parameters, the results of which correlate well with the kinetic data of the process under study. In the course of the research work, the analysis of corrosion deposits was also carried out. The regularities established during the work contribute to the creation of effective di-and polyphosphate inhibitors with the highest degrees of protection.

scholarly journals Optimization of Xylanase Production from Aspergillus foetidus in Soybean Residue

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Luana Cunha ◽  
Raquel Martarello ◽  
Paula Monteiro de Souza ◽  
Marcela Medeiros de Freitas ◽  
Kleber Vanio Gomes Barros ◽  
...  
Keyword(s):  
Experimental Data ◽  
Enzymatic Hydrolysis ◽  
Xylanase Activity ◽  
Statistical Analyses ◽  
Polynomial Model ◽  
Production Level ◽  
Factorial Designs ◽  
Biotechnological Application ◽  
Xylanase Production ◽  
Aspergillus Foetidus

Enzymatic hydrolysis is an important but expensive step in the process to obtain enzyme derived products. Thus, the production of efficient enzymes is of great interest for this biotechnological application. The production of xylanase by Aspergillus foetidus in soybean residues was optimized using 2×23 factorial designs. The experimental data was fitted into a polynomial model for xylanase activity. Statistical analyses of the results showed that variables pH and the interaction of pH and temperature had influenced the production of xylanase, with the best xylanase production level (13.98 U/mL) occurring at fermentation for 168 hours, pH 7.0, 28°C, and 120 rpm.

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