This work aims to investigate the combustion mechanism for a pyrotechnic delay composition (PDC), consisting of zinc powder as a fuel and KMnO as an oxidising agent. For this purpose, the compositions were thermally conditioned at several set temperatures, chosen based on our previous work. Tests were also performed for post-combustion residues obtained via combustion of the PDCs in a manometric bomb. The samples were examined by scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffractometry (XRD). Furthermore, the obtained results were correlated with previous studies by the authors and compared with data available in the literature. On the basis of tests carried out for thermally conditioned samples, a combustion mechanism was determined for Zn/KMnO as a function of temperature. The results show that the combustion process dynamics are independent of equilibrium ratio and limited mainly by diffusion of liquid fuel into the solid oxidising agent. Moreover, it has been revealed that Raman spectroscopy can be effectively used to determine combustion mechanisms for pyrotechnic compositions.
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http://dx.doi.org/10.3390/molecules28155741 | DOI Listing |
Int J Biol Macromol
January 2025
College of Chemistry and Materials Engineering, Zhejiang A&F University, Hangzhou 311300, China. Electronic address:
The development of cellulose fabrics with good flame retardancy and durability has been a primary concern for in firefighting clothing. A recyclable ternary deep eutectic solvent (TDES) was used to prepare surface ammonium phosphate-modified cellulose fabrics (SACF). The incorporation of ammonium phosphate groups notably enhanced the durable flame retardancy of cellulose fabrics.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
Chemical kinetics for second oxygen addition reactions (·QOOH + O) of long-chain alkanes are of great importance in low-temperature combustion technologies. However, kinetic data for key reactions of ·QOOH + O systems are often difficult to obtain experimentally and are primarily estimated or calculated by using theoretical methods. In this work, barrier heights (BHs), reaction energies (Δs), and relative energies (REs) of stationary points for key reactions of two representative ·QOOH + O systems in the low-temperature oxidation of -butyl as well as pressure-dependent rate constants for the involved reactions are calculated with the high-level quantum chemical method CCSD(T)-F12b/CBS.
View Article and Find Full Text PDFPNAS Nexus
January 2025
Southern Research Station, US Forest Service, 320 Green Street, Athens, GA 30602, USA.
Wildfires are growing in destructive power, and accurately predicting the spread and intensity of wildland fire is essential for managing ecological and societal impacts. No current operational models used for fire behavior prediction resolve critical fire-atmospheric coupling or nonlocal influences of the fire environment, rendering them inadequate in accounting for the range of wildland fire behavior scenarios under increasingly novel fuel and climate conditions. Here, we present a new perspective on a dominant fire-atmospheric feedback mechanism, which we term wildland fire entrainment (WFE).
View Article and Find Full Text PDFACS Omega
January 2025
Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India.
The current investigation focuses on the copyrolysis of L. (a nonedible oilseed, also known as Nahar) and polyethyelene terephthalate (PET) plastic waste to gain insights into the composition of pyrolysates and the thermal decomposition of complex and mixed feedstocks. The physicochemical properties of the feedstocks were studied through thermogravimetric analysis at a heating rate of 15 °C min, bomb calorimetry, and proximate/ultimate analysis.
View Article and Find Full Text PDFACS Omega
January 2025
College of Resource and Environment Engineering, Jilin Institute of Chemical Technology, Jilin, Jilin 132022, China.
The inhibition of methane-air explosions by air jet-driven NaHCO powders and porous barriers was investigated in this study. Flame images and overpressure data were recorded using high-speed cameras and pressure sensors. The inhibition mechanism of NaHCO powder was further investigated using the reaction mechanism of sodium-containing substances and methane combustion.
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