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As a fuel commonly used by air heaters for ground tests of high-speed aircraft, the combustion mechanism of ethanol in air heaters is still unclear, especially the atomic-level chemical mechanism of important intermediate products represented by hydrogen in maintaining stable flame combustion needs to be further studied. In this paper, the combustion process of ethanol/oxygen mixtures under different hydrogen additions was simulated using the reactive force field (ReaxFF) molecular dynamics (MD) method. The results show that increasing the proportion of hydrogen in the mixed gas can not only reduce the ignition delay time of ethanol combustion but also promote the consumption of ethanol and accelerate the progress of the combustion reaction. It was also found that hydrogen and ethanol produced a competitive relationship for oxygen, which changed the ideal stoichiometric ratio (1:3) of complete combustion of ethanol and oxygen and significantly affected the intermediate products and reaction paths of ethanol and oxygen. In addition, increasing the combustion reaction temperature will affect the reaction path of ethanol/oxygen, and the number of intermediate products produced will reach the peak faster and then decompose. Theoretical support for a deeper understanding of the intermediate product hydrogen in the combustion of the three-component air heater of ethanol/liquid oxygen/air and also for improving the combustion efficiency of liquid rocket engine fuel are provided in this study.

Manganese-doped calcium aluminate powder was prepared at furnace temperatures as low as 500°C using the combustion route without further calcining treatment. Powder X-ray diffraction, thermogravimetric analysis and scanning electron microscopy measurements were used to characterize the as-prepared combustion products, while the optical properties were studied using photoluminescence. Photoluminescence studies of Mn doped CaAl₂O₄ showed green emission from Mn²⁺ ions. EPR investigations also indicated the presence of Mn²⁺ ions in the prepared material.

For the first of its kind, Cr${}^{3+}$-substituted calcium hexaferrite (CaCr_xFe${}_{12-x}$O${}_{19}$ ($x=1$, 3, 5 and 7)) nanoparticles (NPs) were synthesized via a facile, economical, eco-friendly lemon juice extract mediated green solution combustion method. The samples were calcined followed by characterization. The Bragg reflections confirm the formation of a single phase M-type hexaferrite crystal structure. No other impurity or mixed phases are observed even after the substitution of Cr${}^{3+}$ to the host matrix. Meanwhile, the crystallite size decreases from 29.44 to 19.92nm with an increase in the substitution of Cr${}^{3+}$ ions. The surface morphological analysis shows the presence of agglomerated irregularly shaped NPs. The direct energy band gap estimated using Wood and Tauc’s relation depicts the decrease in energy band gap from 2.98 to 2.74eV with an increase in the substitution of Cr${}^{3+}$ ions. These Cr${}^{3+}$-substituted calcium hexaferrite NPs were predicted to be useful in high-frequency applications based on structural, dielectric, and magnetic studies.

This work investigated combustion performance of the premixed and diffusion burners by measuring flame temperature and gas emissions with used lubricating oil (ULO) and used cooking oil (UCO). Air–fuel ratio (AFR) is an important parameter to investigate combustion performance. Flame temperatures and gas emissions of the burners were examined to know the combustion behavior. The results found were that the flame temperatures in the premixed burner were higher than the diffusion burner at all the AFRs. The maximum flame temperature was obtained at AFR = 16 at all types of burners and fuel blending ratios. The highest flame temperature was $1340^{\circ }\mathrm{\text{C}}$, which occurred when using 100% ULO with premixed burner at AFR = 16. By adding UCO into ULO, the flame temperatures can be decreased. The premixed burner produced 86.67% and 71.23% less CO and HC emissions, respectively, than the diffusion burner, in contrast, the premixed burner formed 26.31% and 54.7% higher ${\mathrm{\text{CO}}}_2$ and ${\mathrm{\text{NO}}}_x$ emissions, respectively, than the diffusion burner.

We have successfully synthesized ZnO nanoparticles (NPs) from solution combustion method using combustible fuel (Green gram). XRD pattern confirms that the prepared compound is composed of wurtzite hexagonal zinc-oxide. FTIR spectrum of ZnO NPs shows the band at ~ 417 cm^-1 associated with the characteristic vibration of Zn-O. The UV-Vis spectrum shows a strong absorption band at ~ 365 nm which is blue shifted due to quantum confinement effect. TEM images show the average sizes of the nanoparticles are found to be almost ~ 15–30 nm. The as-synthesized product shows good electrochemical sensing of dopamine. Furthermore the antibacterial properties of ZnO NPs were investigated by their bactericidal activity against four bacterial strains using the agar well diffusion method.

In the present work, Zinc Oxide nanoparticles (ZnO Nps) have been prepared by a simple and low temperature solution combustion method using Zinc nitrate as a precursor and solid water melon juice as a novel fuel for the first time. The structure and morphology of the synthesized ZnO NPs have been analyzed using various analytical techniques such as Powder X-ray diffraction, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, photoluminescence spectroscopy, scanning electron microscope and transmission electron microscope. ZnO NPs show good photo catalytic activity for the degradation of methylene blue (MB) dye. It also shows significant antibacterial activities against three bacterial strains.

In this paper, we have successfully synthesized ZnO nanoparticles (Nps) via solution combustion method using sugarcane juice as the novel fuel. The structure and morphology of the synthesized ZnO Nps have been analyzed using various analytical tools. The synthesized ZnO Nps exhibit excellent photocatalytic activity for the degradation of methylene blue dye, indicating that the ZnO Nps are potential photocatalytic semiconductor materials. The synthesized ZnO Nps also show good electrochemical sensing of dopamine. ZnO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Eschesichia coli and Staphylococcus aureus using agar well diffusion method. Furthermore, the ZnO Nps show good antioxidant activity by potentially scavenging 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The above studies clearly demonstrate versatile applications of ZnO synthesized by simple eco-friendly route.

Y₂O₃:Eu nanopowders were synthesized by urea combustion method containing different concentration of Eu. The synthesized Y₂O₃:Eu nanopowders were characterized by X-ray diffractometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive X-ray analysis (EDX) and photoluminescence spectroscopy (PL). The particle size was calculated to be in the range of 15–30 nm using Scherrer's formula. The Ia-3 structure of synthesized Y₂O₃:Eu nanopowders were confirmed with X-ray diffractometry. The crystallinity of Y₂O₃:Eu nanopowders were confirmed by SAED and TEM images. The ⁵D₀–∑⁷F_J (J = 0, 1, 2, 3) and ⁵D₁–⁷F₁ transitions bands were observed at 575–650 and 530–550 ranges in the photoluminescence spectrum. The concentration quenching was estimated to be about 5 mol% of Eu. The best chromaticity to the standard red color was observed with the sample containing 3 mol% of Eu.

This paper presents a numerical method to calculate combustion coupled ejection flow in nozzle processes in Liquid Rocket Motor (LRM). A two-dimensional axi-symmetric numerical simulation for the injector element-combustor-and-nozzle model is carried out using the Finite Different (FD) method. In the simulation, the available Computational Fluid Dynamics (CFD) software FLUENT is employed with three key enhancements for material modelling. Firstly, the influence of the two-phase reacting flow is considered, in which the coupled implicit two-step finite difference method to solve the Re-averaged conjugated N-S equation with component conservative equation is used. Secondly, the 17-component, 12-step finite-rate chemical reaction model is employed. Thirdly, the Baldwin-Lomax model is used as turbulence model. These three enhancements are incorporated into the FLUENT code through its user subroutine capability. For both ignition and exhausted stages, the unsteady flow method is used while the steady flow method is adopted for the normally working stage. The distributions of the flow parameter in the combustor-nozzle system are achieved. In addition, the variations of flow parameter along with the time in different stages are also obtained. The results obtained from the numerical simulation are compared with independently available field tests data. Good agreement is observed.

Through the investigation on flame-retardant properties of three kinds of inner-spring mattresses, it is found that without flame retardant, the heat release rate (HRR) of spring mattress is up to 600 kW, the concentration of carbon monoxide (CO) and carbon dioxide (CO₂) is 0.08% and 1.5% respectively. Thus, mattress has a very high fire risk. It could cause injuries and deaths through spreading of fire and emitted gases. The mattress with only fabric treated with flame retardant could be ignited, but did not cause the flame spread across a large area, the flame retardant performance satisfied grade B1 in GB 8624-2012. For the mattress which has both fabric and filler being flame retardant, the flame extinguished soon after the ignition sources were removed. Therefore, flame retardant performance for the last mattress was very well.

Since more than a decade, synchrotron-based methods play a major role in combustion chemistry research. This chapter focuses on the use of synchrotron-generated vacuum-ultraviolet (VUV) radiation as an ionization source in mass spectrometric applications. The use of tunable VUV radiation allows for the detection, identification, and quantification of different isomeric structures, thus adding a new dimension to mass spectrometric experiments which has not been previously accessible. In particular, this chapter highlights flame-sampling and kinetic experiments that provided new detailed insights into combustion chemistry processes. Examples are provided that are concerned with soot precursor formation and the combustion of prototypical biofuels.