scholarly journals A new method for determining stoichiometric coefficients using minors of a matrix

2021 ◽  
Author(s):  
Rainier Lombaard
Keyword(s):  
Chemical Reactions ◽  
Matrix Algebra ◽  
Inverse Method ◽  
Reduction Reaction ◽  
New Method ◽  
Complex Structures ◽  
Metallothermic Reduction ◽  
Mathematical Basis ◽  
Matrix Inverse ◽  
Spinel Materials

The motivation of this study was the investigation into the metallothermic reduction of chromite ores. Spinel materials have complex structures and as a result, balancing of the reduction reactions by traditional methods become very time consuming. A method to calculate the stoichiometric coefficients for chemical reactions using first a modified matrix-inverse method and then a new optimised method is proposed. The mathematical basis of both methods is explored using matrix algebra and then demonstrated using a typical chromite reduction reaction.

scholarly journals A new method for determining stoichiometric coefficients using minors of a matrix

2022 ◽  
Author(s):  
Rainier Lombaard
Keyword(s):  
Linear Algebra ◽  
Chemical Reactions ◽  
Inverse Method ◽  
Reduction Reaction ◽  
New Method ◽  
Complex Structures ◽  
Traditional Methods ◽  
Matrix Inverse ◽  
Spinel Materials

Spinel materials often have complex structures and as a result, balancing of reactions with these compounds by traditional methods become very time consuming. A method to calculate the stoichiometric coefficients for chemical reactions using first a modified matrix-inverse method and then an optimised method is proposed. Both methods are explored using linear algebra and the result demonstrated using a typical chromite reduction reaction.

scholarly journals A method for determining stoichiometric coefficients using minors of a matrix

2022 ◽  
Author(s):  
Rainier Lombaard
Keyword(s):  
Linear Algebra ◽  
Chemical Reactions ◽  
Inverse Method ◽  
Reduction Reaction ◽  
Complex Structures ◽  
Traditional Methods ◽  
Matrix Inverse ◽  
Spinel Materials

Spinel materials often have complex structures and as a result, balancing of reactions with these compounds by traditional methods become very time consuming. A method to calculate the stoichiometric coefficients for chemical reactions using first a modified matrix-inverse method and then an optimised method is proposed. Both methods are explored using linear algebra and the result demonstrated using a typical chromite reduction reaction.

scholarly journals A METHOD FOR DETERMINING STOICHIOMETRIC COEFFICIENTS USING MINORS OF A MATRIX

2022 ◽  
Author(s):  
Rainier Lombaard
Keyword(s):  
Linear Algebra ◽  
Chemical Reactions ◽  
Inverse Method ◽  
Reduction Reaction ◽  
Complex Structures ◽  
Traditional Methods ◽  
Matrix Inverse ◽  
Spinel Materials

Spinel materials often have complex structures and as a result, balancing of reactions with these compounds by traditional methods become very time consuming. A method to calculate the stoichiometric coefficients for chemical reactions using first a modified matrix-inverse method and then an optimised method is proposed. Both methods are explored using linear algebra and the result demonstrated using a typical chromite reduction reaction.

Micron-Scale Diagnostics for Through-Plane Transport Phenomena in Porous Electrodes

2010 ◽  
Author(s):  
Katherine C. Hess ◽  
William K. Epting ◽  
Shawn Litster
Keyword(s):  
Hydrogen Oxidation ◽  
Polymer Electrolyte Membrane ◽  
Transport Phenomena ◽  
Reduction Reaction ◽  
Porous Electrodes ◽  
New Method ◽  
Hydrogen Oxidation Reaction ◽  
Electrolyte Membrane ◽  
Microstructured Electrode ◽  
Accuracy And Repeatability

This paper presents the development of a new method for characterizing the electrochemistry and transport phenomena in the porous electrodes of polymer electrolyte membrane fuel cells (PEMFCs). The new method uses a unique microstructured electrode scaffold (MES) that provide an architecture for obtaining measurements at discrete points through the thickness of an electrode. This paper reports on the design, fabrication and initial testing of an MES for measuring ionic potential across the thickness of a PEMFC’s cathode. The new fuel cell hardware and reference electrodes (REs), which gather electrolyte potential measurements through the thickness of the electrode via the MES, have been tested for accuracy and repeatability. The use of hydrogen oxidation reaction (HOR) REs versus oxygen reduction reaction (ORR) REs is analyzed and discussed. Polarization data was also gathered and the REs are used to separate the half-cell potentials. Finally, the preliminary fabrication of an MES and a micro-structural analysis are discussed.

scholarly journals H2-reduction Behavior of FeS-CaO Mixture during Microwave Heating

2019 ◽  
Author(s):  
Ahmadreza Amini ◽  
Ko-ichiro Ohno ◽  
Takayuki Maeda ◽  
Kazuya Kunitomo ◽  
Keiichiro Kashimura
Keyword(s):  
Activation Energy ◽  
Microwave Irradiation ◽  
Microwave Heating ◽  
Chemical Reactions ◽  
Hydrogen Reduction ◽  
Rapid Heating ◽  
Weight Ratio ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Iron Production

Microwave irradiation is an energy-efficient and a rapid-heating method to decrease the activation energy of chemical reactions via both thermal and non-thermal effects of microwave photons 1). Recently, hydrogen-reduction during microwave heating has been proposed for magnetite reduction to combine the advantages of microwave irradiation and using H2 as a reducing agent during iron production 2). In the present study, as a novel idea, the traditional microwave heating system was equipped with thermobalance to investigate the kinetics of H2-reduction of FeS-CaO mixture (FeS(s) + CaO(s) + H2(g) = Fe(s) + CaS(s) + H2O(g)) under microwave heating at 2.45 GHz to further mitigate CO2 emission and prevent SO2 release during iron production from a sulfide mineral. Microscope observations revealed that the un-reacted core model can be employed for such a kinetic study. Linearity (R2) of different rate-controlling mechanisms after a 10-minute reduction reaction demonstrated that the gas diffusion in micropores of reduced metallic Fe is a dominant rate-controlling mechanism while the interfacial chemical reaction is progressed rapidly. This is attributed to extraordinary effects of microwave irradiation on speeding up the chemical reactions 3), while the formation of Fe shell on the surface of FeS/FeO particles decreases the accessibility of gas to un-reacted parts, resulting in a lower rate of gas diffusion in micropores. Moreover, the diffusion coefficients (De) at 460, 570, and 750 °C were calculated from the plot of the gas diffusion, as illustrated in Fig. 1, wherein the X is reduction degree: where Wi (g) is the initial weight of the sample, Wt (g) is the weight of the sample after treatment for t seconds, Wht (g) is the weight change of the sample owing to the dehydration reaction, and WO (-) is the stoichiometric weight ratio of oxygen in the sample, which is 0.111. Consequently, the activation energy of 22.3 kJ.mol-1 was attained from the Arrhenius equation for the hydrogen-reduction reaction of FeS-CaO mixture under microwave heating.

scholarly journals Uranium Decontamination from Waste Soils by Chlorination with ZrCl4 in LiCl-KCl Eutectic Salt

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Junhyuk Jang ◽  
Tack-Jin Kim ◽  
Sungbin Park
Keyword(s):  
Cyclic Voltammetry ◽  
Chemical Reactions ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
New Method ◽  
Dissolution Behavior ◽  
Salt Mixture ◽  
Natural Soils ◽  
Eutectic Salt ◽  
Obvious Change

The dissolution behavior of U, contained in the soils, was examined through chlorination with ZrCl4 to reduce the U concentration to clearance levels. Natural soils, composed of Si, Al, and approximately 2 ppm U, acted as surrogates for the contaminated soils. A salt mixture of LiCl-KCl-ZrCl4 was prepared in an Al2O3 crucible at 500°C, and SiO2 or natural soils were loaded for the chemical reactions. The reaction of SiO2 and Al2O3 with ZrCl4 was monitored by cyclic voltammetry, and no obvious change was observed. The results showed that SiO2 and Al2O3 were stable against ZrCl4. The reaction of natural soils with ZrCl4 indicated that the U content decreased from 2 to 1.2 ppm, while ∼0.4 ppm U appeared in the salt. Thus, the U, in the soils, dissolved into the salt by chlorination with ZrCl4. Therefore, based on these results, a new method to remediate U-contaminated soil wastes by chlorination with ZrCl4, followed by electrorefining of U, is suggested.

scholarly journals An Attitude Determination Method for Comprehensive Inspection Vehicle Based on Track Profile Registration

2017 ◽  
Vol 45 (4) ◽  
pp. 181
Author(s):  
Yumei Zhang ◽  
Dalin Zhang
Keyword(s):  
Relative Position ◽  
Attitude Determination ◽  
New Method ◽  
Determination Method ◽  
Matrix Inverse ◽  
Contact Measurement ◽  
The Road ◽  
The Matrix ◽  
Determination Methods

The attitude of the comprehensive inspection vehicle is one of the important factors that affect the accuracy of the inspection of metro line infrastructure, meanwhile the metro environment restricts the employment of common attitude determination methods. A new method of attitude determination is presented in this paper, which takes the track as reference and employs non-contact measurement to acquire the track profile simulta-neously. By registration of measurement track profile and the standard track profile, the relative position between the vehicle and the track reference can be calculated; and the instantaneous attitude of the vehicle can be determined by the matrix inverse calculation. The performance of the method is verified by an experiment using the road-rail comprehensive inspection vehicle.

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