Modelling Complex Chemical Processes in Homogeneous Solutions: Automatic Numerical Simulation

2006 ◽  
Vol 11 (3) ◽  
pp. 247-261
Author(s):  
O. V. Klymenko ◽  
I. B. Svir
Keyword(s):  
Chemical Processes ◽  
Local Error ◽  
Homogeneous Solutions ◽  
Biochemical Processes ◽  
Chemical Systems ◽  
Homogeneous Chemical ◽  
Belousov Zhabotinsky Reaction ◽  
New Algorithms ◽  
Ode Systems

Two algorithms for the determination of the necessary limit of local error for the numerical solution of ordinary differential equation (ODE) systems describing homogeneous chemical and biochemical processes, and for the evaluation of their stiffness are developed. The approach for finding the necessary limit of local error of a numerical ODE solver is justified by the proof of the corresponding theorems. The application of the new algorithms implemented in version 2.1 of KinFitSim software to the simulation of real chemical systems is considered on the example of Belousov-Zhabotinsky reaction.

scholarly journals Flow injection analysis of water. Part 1: Automatic preconcentration determination of sulphate, ammonia and iron(II)/iron(III)

1993 ◽  
Vol 15 (4) ◽  
pp. 141-146 ◽  
Author(s):  
J. S. Cosano ◽  
M. D. Luque de Castro ◽  
M. Valcárcel
Keyword(s):  
Flow Injection ◽  
Good Reproducibility ◽  
Chemical Systems ◽  
Sequential Determination ◽  
On Line ◽  
Exchange Material ◽  
Iron Complexation ◽  
Simple Flow ◽  
Ammonia Formation

This paper describes a simple flow-injection (FI) manifold for the determination of a variety of species in industrial water. The chemical systems involved in the determination of ammonia (formation of Indophenol Blue), sulfate (precipitation with Ba(II)), and iron (complexation with 1,10-phenanthroline with the help of a prior redox reaction for speciation) were selected so that a common manifold could be used for the sequential determination of batches of each analyte. A microcolumn of a suitable ion exchange material was used for on-line preconcentration of each analyte prior to injection; linear ranges for the determination of the analytes at the ng/ml levels were obtained with good reproducibility. The manifold and methods are ready for full automation.

Use of Wood Biomass in Slovakia

2014 ◽  
Vol 1001 ◽  
pp. 126-130
Author(s):  
Tomáš Bakalár ◽  
Henrieta Pavolová ◽  
Milan Búgel ◽  
Ľubica Kozáková
Keyword(s):  
Energy Source ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
Organic Material ◽  
Chemical Processes ◽  
Wood Chips ◽  
Wood Biomass ◽  
Biochemical Processes ◽  
Physical Chemical ◽  
Thermochemical Processes

Biomass is organic material, the second most important source of energy. Biomass is a renewable energy source. Wood biomass is used as source of energy for heating in many regions in Slovakia. It is because of its availability. Wood biomass is an easily accessible and affordable source of energy. At present, thermochemical processes, biochemical processes and physical-chemical processes are used for biomass utilization. In the article a suitable technology for combustion of wood chips is proposed. It consists of five main technological parts: transport of wood chips, silo, combustion boiler, and stack.

scholarly journals Belousov-Zhabotinsky type reactions: the non-linear behavior of chemical systems

2021 ◽  
Author(s):  
Andrea Cassani ◽  
Alessandro Monteverde ◽  
Marco Piumetti
Keyword(s):  
Open Systems ◽  
Deterministic Chaos ◽  
General Information ◽  
Operating Conditions ◽  
Chemical Oscillators ◽  
Chemical Systems ◽  
Linear Behavior ◽  
Oscillatory Reactions ◽  
Non Linear ◽  
Belousov Zhabotinsky Reaction

AbstractChemical oscillators are open systems characterized by periodic variations of some reaction species concentration due to complex physico-chemical phenomena that may cause bistability, rise of limit cycle attractors, birth of spiral waves and Turing patterns and finally deterministic chaos. Specifically, the Belousov-Zhabotinsky reaction is a noteworthy example of non-linear behavior of chemical systems occurring in homogenous media. This reaction can take place in several variants and may offer an overview on chemical oscillators, owing to its simplicity of mathematical handling and several more complex deriving phenomena. This work provides an overview of Belousov-Zhabotinsky-type reactions, focusing on modeling under different operating conditions, from the most simple to the most widely applicable models presented during the years. In particular, the stability of simplified models as a function of bifurcation parameters is studied as causes of several complex behaviors. Rise of waves and fronts is mathematically explained as well as birth and evolution issues of the chaotic ODEs system describing the Györgyi-Field model of the Belousov-Zhabotinsky reaction. This review provides not only the general information about oscillatory reactions, but also provides the mathematical solutions in order to be used in future biochemical reactions and reactor designs.

Verified Determination of Singularities in Chemical Processes

2001 ◽  
pp. 305-316 ◽  
Author(s):  
Christian H. Bischof ◽  
Bruno Lang ◽  
Wolfgang Marquardt ◽  
Martin Mönnigmann
Keyword(s):  
Chemical Processes

Application of the Inquiry-based Approach for the Development of Scientific Literacy in the Study of Chemical Processes in Chemistry and Environmental Protection in the 10th Grade

2021 ◽  
Vol 29 (4) ◽  
pp. 370-389
Author(s):  
Yordanka Stefanova ◽  
Keyword(s):  
Environmental Protection ◽  
Scientific Literacy ◽  
Chemical Processes ◽  
Educational Systems ◽  
Research Activity ◽  
Scientific Approach ◽  
Important Means ◽  
Literacy Testing ◽  
Experimental Training

For the future life of young people their scientific education will allow them to live and act adequately in a society influenced by the ideas and values of science. Therefore, in the center of many educational systems an emphasis is placed on forming and developing scientific literacy in students. Inquiry-based approach in education is one of the important means for its formation and development as it puts the students in a situation where they carry out research activity, describe and analyze its results. In this article is presented an attempt to use inquiry-based approach in the study of chemical processes in Chemistry and environmental protection in the 10th. class. For its implementation a methodical model for application of scientific approach based on constructivist theories in education is developed. The results of a conducted experimental training for the determination of the expediency of the model are presented. A test is developed for establishing the training of students with an emphasis on scientific literacy. Testing results show that the developed methodical model creates good conditions for the development of scientific literacy.

Computations by Means of Macroscopic Chemical Kinetics

2006 ◽  
Author(s):  
John Ross ◽  
Igor Schreiber ◽  
Marcel O. Vlad
Keyword(s):  
Chemical Kinetics ◽  
Reaction Mechanisms ◽  
Parallel Machines ◽  
Electronic Device ◽  
Chemical Mechanism ◽  
Chemical Systems ◽  
Universal Turing Machine ◽  
Sequential Machines ◽  
Logic Functions

The topic of this chapter may seem like a digression from methods and approaches to reaction mechanisms, but it is not; it is an introduction to it. We worked on both topics for some time and there is a basic connection. Think of an electronic device and ask: how are the logic functions of this device determined? Electronic inputs (voltages and currents) are applied and outputs are measured. A truth table is constructed and from this table the logic functions of the device, and at times some of its components, may be inferred. The device is not subjected to the approach toward a chemical mechanism described in the previous chapter, of taking the device apart and testing its simplest components. (That may have to be done sometimes but is to be avoided if possible.) Can such an approach be applicable to chemical systems? We show this to be the case by discussing the implementation of logic and computational devices, both sequential machines such as a universal Turing machine (hand computers, laptops) and parallel machines, by means of macroscopic kinetics; by giving a brief comparison with neural networks; by showing the presence of such devices in chemical and biochemical reaction systems; and by presenting some confirming experiments. The next step is clear: if macroscopic chemical kinetics can carry out these electronic functions, then there are likely to be new approaches possible for the determination of complex reaction mechanisms, analogs of such determinations for electronic components. The discussion in the remainder of this chapter is devoted to illustrations of these topics; it can be skipped, except the last paragraph, without loss of continuity with chapter 5 and beyond. A neuron is either on or off depending on the signals it has received. A chemical neuron is a similar device.

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