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Ammonium phosphate fire extinguishing agents, due to their excellent cost-effectiveness and suitability for forest fires, have become one of the most commonly used fire suppressants for forest fire control. Among them, NH 4 H 2 PO 4 fire extinguishing agent is the most widely applied. In this study, NH 4 H 2 PO 4 (>90%) as the main component of dry powder fire extinguishers was selected as the suppressant to investigate the reaction mechanism of NH 4 H 2 PO 4 interacting with red pine wood pyrolysis gas flames. Initially, we constructed a Bunsen burner experimental system suitable for NH 4 H 2 PO 4 /red pine wood pyrolysis gas/air. Although experimental methods yield the most intuitive empirical conclusions, measuring only the laminar flame speed of red pine wood pyrolysis gas/NH 4 H 2 PO 4 /air mixture does not adequately analyze the inhibitory mechanism of NH 4 H 2 PO 4 on red pine wood pyrolysis gas flames. Additionally, due to limitations in experimental equipment and methods, it is not feasible to extend equivalence ratios and NNH 4 H 2 PO 4 doses to large or small working conditions. Therefore, in this study, we utilized Chemkin software to construct theoretical models of flames under different conditions and performed calculations. We comprehensively analyzed the kinetic regulatory mechanisms of NH 4 H 2 PO 4 interacting with red pine wood pyrolysis gas flames from aspects such as chemical inhibition, sensitivity of elementary reactions, elementary reaction yields, and chemical reaction pathways. • The laminar flame velocity of NH 4 H 2 PO 4 interacting with the pyrolysis gas flame of red pine was measured. • A comprehensive analysis of the dynamic regulation mechanism of NH4H2PO4 interaction with pyrolysis gas flame of red pine. • The inhibition mechanism of phosphorus-containing active substances on pyrolysis gas flame of red pine wood was elucidated. • Provide theoretical and experimental reference for development of more efficient fire extinguishing agents for forest fires. [ABSTRACT FROM AUTHOR]

Four kinds of gas generant compositions comprised of 5-aminotetrazole nitrate(5-ATN) as the oxidizing component are provided. The combustion gases are determined through qualitative and quantitative analysis by gas chromatograph, ultraviolet spectrophotometer and a comprehensive system of flue gas analyses. The main components of the combustion gas are N 2 , CO 2 and H 2 as well as a small amount of CO, NO x and NH 3 . Hopcalite is selected as purifying agent, and the results of experiments show that the agent can remove all of the CO and reduce the content of NO x to 100 mg·m -3 , NH 3 to 10 mg·m -3 . [ABSTRACT FROM AUTHOR]

Using Elastic properties of solid materials tester to test the elastic properties of the shell of display shells, obtain that Young's modulus is 2.16 GPa, Shear modulus is 0.87 GPa and Poisson's ratio is 0.241 GPa. Using Instron 5985 Material testing machine to test the tensile mechanical characteristics of the shell, obtain that the tensile yield strength is 14.72 MPa and breaking strength of the shell is 11.20 MPa. For the first time taking pressure expansion leading to shell burst as foundation, the model of display shells is established. The numerical simulation results show that when the unpacking gunpowder is black gunpowder, the unpacking initial velocity is 104.6m/s–114.8m/s. Comparing with the experiment result 112m/s, maximum error is only 7.4m/s, meeting the requirement of precision. When the unpacking gunpowder is black gunpowder the unpacking initial velocity is 303.7m/s–331.2m/s. The unpacking initial velocity can be changed by changing the ratio of charge. [ABSTRACT FROM AUTHOR]

Combustion heat is a very important combustion characteristic of pyrotechnics, and there are lots of methods use combustion heat to evaluate the accidental severity of pyrotechnic safety. In the meantime, combustion heat has profound guiding significance for compound design and safe handling of pyrotechnics. This article utilizes oxygen bomb calorimeter to determine the combustion heat of certain kinds of pyrotechnics, using Hess Law to derive combustion reaction of pyrotechnics that may occur, and analyzing the reasons of differences between the theoretical value with the experimental value. [ABSTRACT FROM AUTHOR]

The thermal decomposition behavior of HBT was studied by TG-DSC thermal analysis method. The decomposition products of HBT were analyzed. TGA curves and differential thermal curves of HBT were measured in different heating rates. The activation energy and pre-exponential factor of HBT was separately calculated by Ozawa equation and Kissinger equation. Thermal decomposition Mechanism of HBT were derived by Ozawa equation and its possible mechanism function was got. The differential thermal curves of HBT prepared by different dispersants were measured and the kinetic parameters were obtained. These kinetic parameters are in good agreement. The test values of the HBT dispersed with acetone have a higher accuracy, so the activation energy calculated is more meaningful. [ABSTRACT FROM AUTHOR]

A new type of multipurpose dry powders (MP dry powders) with melamine phosphate as extinguishing component was prepared by using the ball-milling method. The main physical properties of MP dry powders were tested, and the extinguishing experiments including wood crib fire tests and pool fire tests were conducted to study the extinguishing properties of MP dry powders comparing with commercial ordinary ammonium phosphate dry powders. The thermal decomposition properties of melamine phosphate were studied through thermogravimetric (TG) and differential scanning calorimetry (DSC). The results show that the bulk density of MP dry powders is lower than the required value, and the other main physical properties accord with the demands of Chinese Standards. MP dry powders have higher extinguishing effectiveness on wood crib fire tests and pool fire tests than that of commercial ordinary ammonium phosphate dry powders. Finally, the extinguishing mechanisms were discussed on the base of thermal decomposition properties of melamine phosphate. [ABSTRACT FROM AUTHOR]