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To demonstrate the difference in moisture adsorption properties of fibers and the influence on the moisture adsorption properties of the five plant fibers ( conifer, broadleaf, flax, grass and bamboo) and one regenerated fiber ( Tencel), as well as the adaptability between moisture adsorption properties of fibers and coating performance of reconstituted tobacco for heated tobacco products, were studied. The results showed that the moisture adsorption properties of the six fibers were different. Tencel fiber performed the best, followed by bamboo fiber, and flax fiber performed the worst. The maximum adsorption rate and desorption rate of the fibers increased significantly with the increase of relative humidity during moisture migration. The parallel exponential dynamic model (PEK) was used to fit the moisture migration, it indicated that the progress consisted of a fast and a slow sorption procedure which occurred simultaneously. The fast procedure dominated the water migration behaviour in the sheet. As the relative humidity increased, the equilibrium moisture absorption content of the fast procedure increased and its characteristic time decreased. Meanwhile, the characteristic parameters of the slow procedure had no obvious rule with relative humidity. The micro-structure morphology, environmental conditions and other factors strongly influenced the moisture adsorption properties of fibers, the hygroscopic properties of fibers were positively correlated with the relative humidity ( RH), negatively correlated with the crystallization of cellulose, while the temperature showed a weak effect on it. It was found that the reconstituted tobacco sheet showed outstanding coating performance including water and coating liquid with the application of excellent hygroscopic fibers under the condition of adding the same amount ratio during application. [ABSTRACT FROM AUTHOR]

A comprehensive two-dimensional (2D) mathematical model has been proposed to simulate the burning process of a king-size cigarette. The characteristics of this model are including: 1) the use of kinetic models for the evaporation of water, the pyrolysis of tobacco and the oxidation of char, 2) the application of mathematical relationships between the release amounts of certain products (i.e., "tar" and CO) and different reaction variables (i.e., temperatures and oxygen concentrations), 3) the introduction of mass, heat and momentum transports, 4) the consideration of filtration effects of the cigarette filter on "tar". These characteristics were expressed in a set of coupled equations that can be solved numerically by FLUENT. The information about the char density field, temperature field, flow velocity field, "tar" and CO density fields and the filtration efficiency could be obtained from the model. This model was validated by comparing the predictions with experimental data on puff number, the temperatures at specific locations, the filtration efficiency and the yields of "tar" and CO under different puff intensities. The calculated results show a good agreement with the experimental data. The predicted puff number was 7.3, and the experimental puff number was 6.8. The standard root mean square error (NRMSE) between the experimental and the predicted temperatures at specific locations is < 18%. The predicted filtration efficiency for "tar" was 46.1%, and the experimentally determined filtration efficiency for nicotine was 44.5%. The maximum relative deviations of the yields of "tar" and CO under different puff intensities were 8.9% and 10.6%, respectively. [ABSTRACT FROM AUTHOR]

The regulation of hollow morphology, band structure modulation of solid solution, and introduction of cocatalysts greatly promote the separation of electron-hole pairs in photocatalytic processes, which is of great significance for the process of photocatalytic hydrogen evolution (PHE). In this study, we constructed Zn 1- x Cd x S hollow solid solution photocatalysts using template and ion exchange methods, and successfully loaded PdS quantum dots (PdS QDs) onto the solid solution through in situ sulfidation. Significantly, the 0.5 wt% PdS QDs/Zn 0.6 Cd 0.4 S composite material achieved a H 2 production rate of 27.63 mmol g -1 h -1 in the PHE process. The hollow structure of the composite material enhances processes such as light reflection and scattering, the band structure modulation of the solid solution enables the electron-hole pairs to reach an optimal exciton recombination balance, and the modification of PdS QDs provides abundant sites for oxidation, thereby promoting the proton reduction and hydrogen evolution rate. This work provides valuable guidance for the rational design of efficient composite PHE catalysts with strong internal electric field.