The kinetics and mechanism of B2O3 formation from the chemically-synthesized HBO2 under non-isothermal conditions

Abstract

In this investigation, a crystalline metaboric acid (HBO 2 ) powder was subjected to a dehydration process to transform it into boron oxide (B 2 O 3 ) using thermogravimetry (TG) technique in an argon atmosphere under non-isothermal conditions at different heating rates (3, 5, 10, and 15 °C min −1 ). The results of kinetic analysis revealed that the dehydration process was a complex one comprising a consecutive region (region I) followed by a parallel one (region II). Using the relevant kinetic models, the mechanisms involved in each region were analyzed by a proposed method for the complex reactions separately and find that the dehydration mechanism in the region I consisted of the kinetic models R 4 : g(α) = [1 − (1 − α) 2/3 ] (the chemical reaction at the HBO 2 /H 2 B 4 O 7 interface) and D 3 : g(α) = [1 − (1 − α) 1/3 ] 2 (the diffusion of H 2 O (g) in the H 2 B 4 O 7 layer), while that in the region II was parallel and consisted of the models D 3 (the diffusion of H 2 O (g) in the H 2 B 4 O 7 layer) and R 4 (the chemical reaction at the of H 2 B 4 O 7 /B 2 O 3 interface). Therefore, based on the kinetic results, the mechanisms of complex processes could be determined by the method.

[Retracted] Analysis of the Natural Conditions and Geographical Factors of the Formation of Hui‐Style Prints

“…At the same time, the favorable factors during the formation of Hui-style prints can be increased to have the disks containing single/bilateral cracks connected by means of docking when the artists are drawing their different works to ensure that the radial concentration force P inside can be applied to each area, to complete the detection of infinite steel stress, and to control the strength factors in the formation stage of Hui-style printmaking to promote the operation of artists to be more standardized and analyze the deficiencies in the formation stage of Hui-style printmaking so that the double cracks and single cracks can be more intuitively shown (as shown in Figure 8 ) [ 19 , 20 ].…”

The Influence of Noise Exposure at Different Loudness Levels on EEG Index and Types of Attention

“…In such cases, applying sound quality or psychoacoustic criteria in such cases seems more logical. [ 5 6 7 ] Psychoacoustics determines the functional relationships between the physical properties of noise and auditory sensory phenomena. [ 8 ]…”