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Ziegler Barry posted an update 1 day, 7 hours ago
The reaction kinetics of solid fuel is a critical aspect of energy production because its energy component is determined during the process. read more The overall fuel quality is also evaluated to account for a defined energy need. In this study, a two-step first-order reaction mechanism was used to model the rapid mass loss of pine sawdust (PSD) during torrefaction using a thermogravimetric analyzer (Q600 SDT). The kinetic analysis was carried in a MATLAB environment using MATLAB R2020b software. Five temperature regimes including 220, 240, 260, 280, and 300 °C and a retention time of 2 h were used to study the mechanism of the solid fuel reaction. Similarly, a combined demarcation time (i.e., estimating the time that demarcates the first stage and the second stage) and iteration technique was used to determine the actual kinetic parameters describing the fuel’s mass loss during the torrefaction process. The fuel’s kinetic parameters were estimated, while the developed kinetic model for the process was validated using the experimental data. The solid and gas distributions of the components in the reaction mechanism were also reported. The first stage of the degradation process was characterized by the rapid mass loss evident at the start of the torrefaction process. In contrast, the second stage was characterized by the slower mass loss phase, which follows the first stage. The activation energies for the first and second stages were 10.29 and 141.28 kJ/mol, respectively, to form the solids. The developed model was reliable in predicting the mass loss of the PSD. The biochar produced from the torrefaction process contained high amounts of the intermediate product that may benefit energy production. However, the final biochar formed at the end of the process increased with the increase in torrefaction severity (i.e., increase in temperature and time).In this work, nanocomposites of poly(methyl methacrylate) (PMMA) with cellulose nanofiber (CNF) were prepared by a solution casting technique. CNF was modified by propionic anhydride (PA) to form surface-propionylated CNF (CNFp) to improve its compatibility with the PMMA matrix. CNF, CNFp, and acetylated CNF were compared with respect to their influence as fillers in PMMA composite films by ultraviolet-visible transmittance, haze values, tensile strength testing, and water contact angle measurement. It was demonstrated that 1 wt % of CNFp has good compatibility and uniform dispersion in the PMMA matrix, as demonstrated by the formation of a smooth surface composite film with good transparency, enhanced tensile properties, improved toughness, and lower wettability. Therefore, PMMA/CNFp composite films have great potential for use in several applications such as lightweight transparent materials, window substitutes, and see-through packaging.To utilize the chemical application of lignin (LN), a decomposition reaction was carried out to cleave chemical bonds. Indeed, a liquefaction process is essential for the chemical use of lignin to achieve a uniform reaction and maximize the chemical utility of lignin. To this end, hydroxyl radicals were adopted as a powerful oxidation agent, and FT-IR results confirmed the cleavage of the ether linkages. Additionally, the water solubility of LN significantly increased after decomposition, and dissolution levels up to 0.5 g·mL-1 were obtained. Using these high solubility properties in water, NMR and DLS analyses were performed. In particular, an average particle diameter of 300 ± 240 nm was found, corresponding to the size of polydisperse l-LN. By controlling size uniformity and using high water-solubility levels, polyurethane foams were manufactured using l-LN.Quantum dots (QDs) and carbon quantum dots (CDs) are classes of zero-dimensional materials whose sizes can be ≤10 nm. They exhibit excellent optical properties and are widely used to prepare fluorescent probes for qualitative and quantitative detection of test objects. In this article, we used cerium chloride as the cerium source and used the in situ doped cerium (rare-earth element) to develop cadmium telluride (CdTe) quantum dots following the aqueous phase method. CdTe Ce quantum dots were successfully synthesized. The solution of CdTeCe QDs was mixed with the CD solution prepared following the green microwave method to form a ratio fluorescence sensor that can be potentially used for the selective detection of mercury ions (Hg2+). We used transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and other microscopy and spectral characterization techniques to validate that Ce had been successfully doped. The test results on the fluorescence performance revealed that Ce doping enhances the predoped fluorescence performance of the CdTe QDs. We have quantitatively detected Hg2+ using a ratiometric fluorescence sensor to show that in the range of 10-60 nM, the fluorescence quenching efficiency increases linearly with the increase in Hg2+ concentration. The linear correlation coefficient R 2 = 0.9978, and its detection limit was found to be 2.63 nM L-1. It was observed that other interfering ions do not significantly affect the fluorescence intensity of the probe. According to the results of the blank addition experiment, the developed proportional fluorescence probe can be used for the detection of Hg2+ in actual samples.High-efficiency nanotheranostic agents with multimodal imaging guidance have attracted considerable interest in the field of cancer therapy. Herein, novel silver-decorated bismuth-based heterostructured polyvinyl pyrrolidone nanoparticles (NPs) with good biocompatibility (Bi-Ag@PVP NPs) were synthesized for accurate theranostic treatment, which can integrate computed tomography (CT)/photoacoustic (PA) imaging and photodynamic therapy/photothermal therapy (PDT/PTT) into one platform. The Bi-Ag@PVP NPs can enhance light absorption and achieve a better photothermal effect than bismuth NPs. Moreover, after irradiation under an 808 nm laser, the Bi-Ag@PVP NPs can efficiently induce the generation of reactive oxygen species (ROS), thereby synergizing PDT/PTT to exert an efficient tumor ablation effect both in vitro and in vivo. Furthermore, Bi-Ag@PVP NPs can also be employed to perform enhanced CT/PA imaging because of their high X-ray absorption attenuation and enhanced photothermal conversion. Thus, they can be utilized as a highly effective CT/PA imaging-guided nanotheranostic agent.